Effect of shot peening and treatment temperature on wear and corrosion resistance of sequentially plasma treated AISI 316L steel
M RABELO MENEZES, [...], Surface and Coatings Tech, [HommelMap]
Austenitic stainless steels exhibit excellent corrosion resistance but relatively poor wear resistance. Previous investigations have demonstrated that surface treatments consisting of plasma carburizing and plasma nitriding were able to successfully increase the wear resistance of austenitic stainless steels. In this work, the effect of a prior shot peening (SP) process on wear and corrosion resistance of sequentially plasma carburized and plasma nitrided AISI 316L austenitic stainless steel was investigated. Triode plasma carburizing (TPC) and triode plasma nitriding (TPN) were sequentially carried out at two temperatures: 400°C and 475°C. SP processing prior to sequential plasma treatments led to a significant increase in the near-surface hardness. The sequential plasma treatment at 475°C in combination with a SP pre-treatment promoted a further increase in thicknesses of carburized and nitrided layers, leading to a greater hardening depth. The best wear resistance exhibited by austenitic AISI 316L samples subjected to SP and sequential plasma processing at higher temperature could be attributed to their high surface hardness and greater treatment depth. However, this treatment at higher temperature yielded CrN precipitates that impaired the corrosion resistance in aerated 0.5 M H2SO4 aqueous solution. Electrochemical tests also revealed that the use of shoot peening prior to sequential plasma treatments at 475 °C could partially counteract the deleterious reduction in corrosion resistance promoted by chromium nitride precipitation at this higher processing temperature. Although the precipitation of chromium nitrides at higher plasma processing temperatures promoted a reduction in corrosion resistance in such acidic environment, results indicate that austenitic stainless steels modified by shot peening (SP) followed by sequential plasma treatments at high processing temperatures could be potentially used in applications where high wear resistance and moderate corrosion resistance in specific environments are required.
[PDF] Evaluation of surface quality of X210CR12 steel for forming tools machined by WEDM
M MOURALOVA, R ZAHRADNICEK, P HOUSKA, [Talymap]
The stressed parts of forming tools are usually made of tool alloy steel X210Cr12 with additional thermal treatment. When machining these parts, due to the high demands on shape and precision, wire electrical discharge machining (WEDM) is used, which a method is belonging to the group of non-convention machining technologies. WEDM uses physical principles to cut
material, which enables for machining parts which were already thermally treated. The long-term trend of improving precision and quality of the machined surface leads to the necessity of its thorough studying. This study concerns itself with evaluating the morphology of the worked surface using electron
microscopy (SEM) and chemical composition analysis (EDX). The focus was to evaluate the quantity of the adhered material from the brass wire electrode. Furthermore, surface and profile parameters of the machined surface were studied using Atomic force microscope (AFM). Samples for the experiment were
made of X210Cr12 steel, which was treated with 4 different thermal treatments.
Surface-Sensitive Microwear Texture Analysis of Attrition and Erosion
S RANJITKAR, [...], J Dental Research, [SensoMap]
Scale-sensitive fractal analysis of high-resolution 3-dimensional surface reconstructions of wear patterns has advanced our knowledge in evolutionary biology, and has opened up opportunities for translatory applications in clinical practice. To elucidate the microwear characteristics of attrition and erosion in worn natural teeth, we scanned 50 extracted human teeth using a confocal profiler at a high optical resolution (X–Y, 0.17 µm; Z < 3 nm). Our hypothesis was that microwear complexity would be greater in erosion and that anisotropy would be greater in attrition. The teeth were divided into 4 groups, including 2 wear types (attrition and erosion) and 2 locations (anterior and posterior teeth; n = 12 for each anterior group, n = 13 for each posterior group) for 2 tissue types (enamel and dentine). The raw 3-dimensional data cloud was subjected to a newly developed rigorous standardization technique to reduce interscanner variability as well as to filter anomalous scanning data. Linear mixed effects (regression) analyses conducted separately for the dependent variables, complexity and anisotropy, showed the following effects of the independent variables: significant interactions between wear type and tissue type (P = 0.0157 and P = 0.0003, respectively) and significant effects of location (P < 0.0001 and P = 0.0035, respectively). There were significant associations between complexity and anisotropy when the dependent variable was either complexity (P = 0.0003) or anisotropy (P = 0.0014). Our findings of greater complexity in erosion and greater anisotropy in attrition confirm our hypothesis. The greatest geometric means were noted in dentine erosion for complexity and dentine attrition for anisotropy. Dentine also exhibited microwear characteristics that were more consistent with wear types than enamel. Overall, our findings could complement macrowear assessment in dental clinical practice and research and could assist in the early detection and management of pathologic tooth wear.
[PDF] Effect of Scanning Speed and Gas Flow Rate on Surface Roughness of LMD Titanium-alloy
R M MAHAMOOD, E T SKINLABI, Proc W Congress Eng Computer Sci, [HommelMap]
This study investigated the effect of scanning speed and gas flow rate on surface finish produced during the laser metal deposition process of Ti6Al4V, an important aerospace alloy. In this work, Nd-YAG laser was employed with coaxial powder deposition nozzle attached to the end effector of a Kuka robot. The laser power was maintained at 3.0 kW and the powder flow rate at a value 2.88 g/min. The scanning speed was varied between 0.01 and 0.05 m/s and the gas flow rate was varied between 1 and 5 l/min. A total of ten
samples were produced and the surface roughness was measured using the average of five measurements from each sample. The microstructure was also studied with
optical microscope to relate it to the surface roughness. The results showed that, the average surface finish increased as the scanning speed was increased.
Conversely, as the gas flow rate was increased the average surface roughness was reduced. In optimizing the laser metal deposition process, the processing
parameters need to be optimized. The results from this study will assist in choosing the right powder flow rate and scanning speed especially in applications such as repair and surface modification.
How long does the volumizing effect of a Zingiber officinale-based lip plumper last?
V MAZZARELLO, [...], Int J Cosmetic Sci, [MountainsMap]
Effectiveness was assessed using non-invasive techniques. The effect on vascularisation was analyzed with the Mexameter MX 16®, and the volume enhancing effect was assessed by anthropometric measures and profilometry analysis from 3D scanning electron microscope (SEM) images using Alicona's MEX software. Sixty female volunteers were recruited for the study and the measurements were taken 15, 30, 60, 90 and 120 min after product application. Product application produced a statistically significant increase of lip vascularisation during the first 15 min, which stayed unchanged until the 30th min, then decreased in intensity. The volumizing effect was revealed by 3D profilometry analysis only, not by anthropological measurements. The use of 3D SEM images showed an increase of 0.50 mm in the protrusion of the lip vermilion (MHP parameter) during the first 15 min from product application. Results suggest that the lip plumper temporarily enhances vasodilation and increases lip volume.
~12% Efficiency improvement in a-Si thin-film solar cells using ALD grown 2-nm-thick ZnO nanoislands
F I CHOWDHURY, [...], Photovoltaic Specialists Conference, [MountainsMap]
2-nm-thick ZnO nanoislands have been grown using Atomic Layer Deposition (ALD) on the surface of n-i-p a-Si:H solar cells. With the nanoislands, an average improvement of 10.6% in short circuit current density (Jsc) and 12.05% in efficiency compared to the reference cell are achieved. Improved spectral response is obtained from ZnO nanoislands coated cell with an improvement of 4.2% and 5.25% in peak EQE and IQE respectively. The coated cell also minimizes reflection between 340-520 nm indicating light scattering ability of these nanoislands. Further analysis suggests that overall enhancement can be attributed to photon energy downshifting with a reduction in reflectivity.
Metal-Oxide Decorated Multilayered Three-Dimensional (3D) Porous Carbon Thin Films for Supercapacitor Electrodes
K MONDAL, R KUMAR, A SHARMA, Ind Eng Chem Res, [PicoImage]
We demonstrate an easy, scalable, and two-step synthesis of macroporous carbon, carbon/TiO2 (cTiO2), carbon/MnO2 (cMnO2), and carbon/TiO2/MnO2 (cTiO2/MnO2) composite thin films for energy storage applications. The direct synthesis of the hybrid films was achieved by spin coating, followed by carbonization. The unique multilayered three-dimensional (3D) pore structure of the film permits the synthesis of carbon/TiO2/MnO2 nanocomposites with enhanced metal-oxide nanoparticle loading up to 50 wt %. The as-synthesized porous carbon thin films were tested for their supercapacitor activity and a maximum specific capacitance ∼44 F g–1 was achieved with a film thickness of 350 nm. The as-prepared cTiO2, cMnO2, and cTiO2/MnO2 electrodes exhibit high specific capacitances of 178, 237, and 297 F g–1, respectively, at 5 mV s–1, because of their unique properties with impregnated nanoparticles, and direct fabrication on conductive substrates. This simple scalable coating technique is compatible with the high-speed roll-to-roll manufacturing processes and easily generalized for other carbon/metal oxide composites. We demonstrate an easy, scalable, two-step synthesis method similar to the roll-to-roll process for the synthesis of multilayered of macroporous carbon, carbon/TiO2 (cTiO2), carbon/MnO2 (cMnO2), and carbon/TiO2/MnO2 (cTiO2/MnO2) composite thin films for energy storage applications.
Middle Stone Age Ochre Processing and Behavioural Complexity in the Horn of Africa: Evidence from Porc-Epic Cave, Dire Dawa, Ethiopia
D E ROSSO, A PITARCH MARTI, F D'ERRICO, PLOS One [LeicaMap]
Ochre is a common feature at Middle Stone Age (MSA) sites and has often been interpreted as a proxy for the origin of modern behaviour. However, few ochre processing tools, ochre containers, and ochre-stained artefacts from MSA contexts have been studied in detail within a theoretical framework aimed at inferring the technical steps involved in the acquisition, production and use of these artefacts. Here we analyse 21 ochre processing tools, i.e. upper and lower grindstones, and two ochre-stained artefacts from the MSA layers of Porc-Epic Cave, Dire Dawa, Ethiopia, dated to ca. 40 cal kyr BP. These tools, and a large proportion of the 4213 ochre fragments found at the site, were concentrated in an area devoted to ochre processing. Lower grindstones are made of a variety of raw materials, some of which are not locally available. Traces of use indicate that different techniques were employed to process ochre. Optical microscopy, XRD, μ-Raman spectroscopy, and SEM-EDS analyses of residues preserved on worn areas of artefacts show that different types of ferruginous rocks were processed in order to produce ochre powder of different coarseness and shades. A round stone bearing no traces of having been used to process ochre is half covered with residues as if it had been dipped in a liquid ochered medium to paint the object or to use it as a stamp to apply pigment to a soft material. We argue that the ochre reduction sequences identified at Porc-Epic Cave reflect a high degree of behavioural complexity, and represent ochre use, which was probably devoted to a variety of functions.
Orientation symmetry breaking in self-assembled Ce1−xGdxO2−y nanowires derived from chemical solutions
A QUERALTO, [...], RSC Adv, [MountainsMap]
Understanding the growth mechanisms of nanostructures obtained from chemical solutions, a high-throughput production methodology, is essential to correlate precisely the growth conditions with the nanostructures' morphology, dimensions and orientation. It is shown that self-organized (011)-oriented Ce0.9Gd0.1O2−y (CGO) nanowires having a single in-plane orientation are achieved when an anisotropic (011)-LaAlO3 (LAO) substrate is chosen. STEM and AFM images of the epitaxial nanowires reveal the (001)CGO[0−11]||(011)LAO[100] growth orientation, with the enlargement occurring along the [0−11]CGO direction with (111) lateral facets. The chosen substrate allowed us to study a unique case where the resulting biaxial strain is isotropic, while the dissimilar lateral surface energies are the key factor to obtain an energetically imbalanced and non-degenerated nanowire configuration. Rapid Thermal Annealing (RTA) has allowed sorting of experimental nucleation from coarsening and analysis of the kinetic phenomena of the nanowires. A thermodynamic driving force is shown to exist for a continuous elongation of the nanowires while the coarsening rates are found to be strongly temperature dependent and so kinetic effects are the key factors to control the size and density of the self-organized nanowire system. A remarkably fast nanowire growth rate (14–40 nm min−1) is observed, which we associate with a high atomic mobility probably linked to a high concentration of oxygen vacancies, as detected by XPS. These nanowires are envisaged as model systems pushing forward the study of low energetic and highly oxygen deficient {111} lateral facets useful for catalysis, gas sensors and ionic conductivity applications.
Molecular Interactions between a Biodegradable Demulsifier and Asphaltenes in an Organic Solvent
A NATARAJAN, [...], Energy&Fuels, [PicoImage]
A surface forces apparatus (SFA) was used to measure the intermolecular forces between a biodegradable demulsifier (ethyl cellulose, EC) and asphaltenes immobilized individually on molecularly smooth mica surfaces in an organic solvent. A steric repulsion on approach between the immobilized EC layers and asphaltenes was measured despite strong adhesion (Fad/R ≈ −2 mN/m; Wad = 0.42 mJ/m2) during retraction. The measured adhesion was attributed to the interpenetration and tangling of aliphatic branches of swollen asphaltenes and solvated chains of EC macromolecules. Competitive adsorption of EC on/in immobilized asphaltene layers was confirmed by combining SFA force measurements and atomic force microscopy (AFM) imaging. Following the injection of EC-in-toluene solution, an immediate (<5 min) increase in the confined layer thickness of the immobilized asphaltene layers was measured. Irreversibly adsorbed asphaltenes were displaced by EC macromolecules through binding with unoccupied surface sites on mica, followed by the spreading of EC across the mica substrate due to increased surface activity governed by the higher number of hydroxyl groups per EC molecule. AFM imaging confirmed that the increase in confined layer thickness resulted from the formation of larger asphaltene aggregates/clusters protruding from the mica substrate. Molecular level topographical images showed that the asphaltenes were not resolvated in the organic phase but self-associated as the EC macromolecules spread across the hydrophilic mica substrate. The results from this study provide not only fundamental insights into the basic interaction mechanisms of asphaltenes with EC macromolecules as a demulsifier in organic media but also directions toward enhancing demulsification of water-in-oil emulsions.
High-temperature Na2SO4 deposit-assisted corrosion of silicon carbide–II: Effects of B, C, and Si
J M HAGAN, E J OPILA, J American Ceramic Soc, [MountainsMap]
The effects of boron, carbon, and silicon on the Na2SO4 induced hot corrosion of sintered-α (Hexoloy) and CVD-SiC coupons were studied to elucidate the hot corrosion of SiC-based ceramic matrix composites. The extent of corrosion was quantified after 24 hour exposures at 1000°C using mass change measurements, inductively coupled plasma optical emission spectrometry analysis of corrosion products, and optical profilometry of pitting on the substrate surface. In addition, scanning electron microscopy and X-ray diffraction were used to better understand the morphology, distribution, and phase composition of corrosion products. It was found that Si was more resistant to hot corrosion than SiC, indicating that residual Si in a ceramic matrix composites matrix should not negatively impact hot corrosion resistance of the composite in highly oxidizing conditions. Carbon did not have a large impact on hot corrosion of SiC, whereas the presence of boron made the hot corrosion attack more severe.
Multi-sensor measurements of titanium alloy surface texture formed at subsequent operations of precision machining process
M NIEMCZEWSKA-WOJCIK, Measurement, [MountainsMap]
The paper presents the issues concerning difficult-to-machine materials along with machining process and technologies used to measure surface topography. Thorough research comprising precision machining process and multi-sensor measurements enabled multi-scale analysis of surface texture. The subjects of the study were titanium alloys TiAlSiZr. The semi-finished products were subjected to precision abrasive machining process which consisted of preliminary grinding, precision grinding, lapping, and polishing. The surface texture obtained after each operation of machining process was measured using a white light interference microscopy, a scanning electron microscopy and an atomic force microscopy. The measurement results obtained from the multi-scale analysis show differences in the surface texture of titanium alloys, resulting mainly from machining conditions including the applied tools (grains and micrograins of diamond). Surface defects, e.g. grinding cracks (preliminary grinding), dales of different geometry (precision grinding), scratches and the distribution of dales/dents (lapping and polishing) influencing surface functional properties were discussed.
[PDF] Investigating the potential of combined growth factors delivery, from non-mulberry silk fibroin grafted poly(ε-caprolactone)/hydroxyapatite nanofibrous scaffold, in bone tissue engineering
P BHATTACHARJEE, [...], Applied Mat Today, [PicoImage]
Mineralized scaffoldshave the advantage of bettermimicking thenatural bone structure and thus show an improved potential for bone tissue engineering. This study uses cycles of alternative soaking to deposit hydroxyapatite (HAp) layers upon non-mulberry silk fibroin (from Antheraea mylitta) grafted poly(ε-caprolactone) nanofibrous matrices. Alternate soaking, of one through three cycles, is used due to its
simplicity and deposition efficiency. HAp deposition improved mechanical strength of the scaffolds up to two cycles of soaking (by nearly 75%). Analysis of mechanical properties, bioactivity and in vitro study results (with MG-63 cell line) showed scaffolds fabricated using two-cycle soaking to be the most suitable. These constructs were loaded with growth factors (transforming growth factor beta (TGF-β) 4 ng and bone morphogenic protein-2 (rhBMP-2) 100 ng) using carbodiimide-coupling reaction. The following three different combinations of growth factor loaded composites were analyzed: solely rhBMP-2,
solely TGF-β and rhBMP-2-TGF-β combinations. Scaffolds with both growth factors supported cellular activity and proliferation better (p < 0.01), generated greater calcium deposits (p < 0.01), facilitated early cell differentiation and yielded significantly better expression of genes linked to bone growth (p < 0.05). These dual growth factor loaded scaffolds are mechanically robust and enhance cell proliferation and early differentiation of osteoblast-like cells. They thus show potential of being further optimized for use in bone tissue engineering.
The High Speed Wire Drawing Process of Steel Wires under Fluid Frictions Conditions
M SULIGA, Key Eng Mat, [Talymap]
The essential purpose of the work was to determine the phenomena that occur in multipass wire drawing process of high carbon steel wires with high speed in hydrodynamic dies and to assess their influence on moulding the wire properties after the drawing process. The multiparameter analysis of the issues has involved the theoretical dissection of the phenomena arising in high speed wire drawing process in hydrodynamic dies with the usage of the finite element method supported by the experimental multipass drawing process in industrial conditions. On the basis of numerical analysis the influence of drawing speed on wire temperature was estimated. For final wires the investigation of mechanical properties, topogrhaphy of wire surface, the amount of lubricant on the wire surface, the pressure of lubricant in hydrodynamic dies were determined.
Adhesion force mapping on wood by atomic force microscopy: influence of surface roughness and tip geometry
X JIN, B KASAL, Royal Society Open Sci, [PicoImage]
This study attempts to address the interpretation of atomic force microscopy (AFM) adhesion force measurements conducted on the heterogeneous rough surface of wood and natural fibre materials. The influences of wood surface roughness, tip geometry and wear on the adhesion force distribution are examined by cyclic measurements conducted on wood surface under dry inert conditions. It was found that both the variation of tip and surface roughness of wood can widen the distribution of adhesion forces, which are essential for data interpretation. When a common Si AFM tip with nanometre size is used, the influence of tip wear can be significant. Therefore, control experiments should take the sequence of measurements into consideration, e.g. repeated experiments with used tip. In comparison, colloidal tips provide highly reproducible results. Similar average values but different distributions are shown for the adhesion measured on two major components of wood surface (cell wall and lumen). Evidence supports the hypothesis that the difference of the adhesion force distribution on these two locations was mainly induced by their surface roughness.
[PDF] Multilayer solar selective coatings for high temperature solar applications: From concept to design
I HERAS PEREZ, PhD Thesis, U Sevilla, [SensoMap]
Increasing the share of renewables in the energy mix has a key function for the security of energy supply and the reduction of greenhouse gas emissions from fossil fuels. The purpose of this thesis is to develop new solar selective coating (SSC) designs for high temperature applications in order to improve the performance of concentration solar power (CSP) plants. The main part of this thesis has been carried out in the company Abengoa, which is a world leader in the development of CSP plants, but also with the collaboration of other wellrecognized academic organizations (Instituto de Ciencia de Materiales de Sevilla-CSIC, Center Tecnologic Manresa and the Helmholtz-Zentrum Dresden - Rossendorf) and the SME Metal Estalki.
The improvement in efficiencies in solar thermal energy plants partially means the increase in the receivers’ temperature, reaching up to an average maximum temperature of 650ºC for superheated steam and molten salts receivers. There are several R&D approaches to substitute commercial absorber paints due to the degradation problems they show at high temperatures when exposed to air. The different routes include the development of new solar selective coatings
fabricated using physical vapour deposition techniques. In this thesis, two potential candidates as solar selective coatings were selected: i) carbon–
transition metal carbides nanocomposites (a-C:MeC) and ii) aluminium titanium oxynitride (AlTi(OxN1-x)) based coatings.
Effect of enzymatic degradation of chitosan in polyhydroxybutyrate/chitosan/calcium phosphate composites on in vitro osteoblast response
M GIRETOVA, [...], J Mat Sci, [SensoMap]
Polyhydroxybutyrate/chitosan/calcium phosphate composites are interesting biomaterials for utilization in regenerative medicine and they may by applied in reconstruction of deeper subchondral defects. Insufficient informations were found in recent papers about the influence of lysozyme degradation of chitosan in calcium phosphate/chitosan based composites on in vitro cytotoxicity and proliferation activity of osteoblasts. The effect of enzymatic chitosan degradation on osteoblasts proliferation was studied on composite films in which the porosity of origin 3D scaffolds was eliminated and the surface texture was modified. The significantly enhanced proliferation activity with faster population growth of osteoblasts were found on enzymatically degraded biopolymer composite films with α-tricalcium phosphate and nanohydroxyapatite. No cytotoxicity of composite films prepared from lysozyme degraded scaffolds containing a large fraction of low molecular weight chitosans (LMWC), was revealed after 10 days of cultivation. Contrary to above in the higher cytotoxicity origin untreated nanohydroxyapatite films and porous composite scaffolds. The results showed that the synergistic effect of surface distribution, morphology of nanohydroxyapatite particles, microtopography and the presence of LMWC due to chitosan degradation in composite films were responsible for compensation of the cytotoxicity of nanohydroxyapatite composite films or porous composite scaffolds.
A biophysical investigation on the binding of proflavine with human hemoglobin: Insights from spectroscopy, thermodynamics and AFM studies
A BASU, G SURESH KUMAR, J Photochemistry and Photobiology, [PicoImage]
Interaction of proflavine with hemoglobin (Hgb) was studied employing spectroscopy, calorimetry, and atomic force microscopy. The equilibrium constant was found to be of the order 104 M− 1. The quenching of Hgb fluorescence by proflavine was due to the complex formation. Calculation of the molecular distance (r) between the donor (β-Trp37 of Hgb) and acceptor (proflavine) suggested that energy can be efficiently transferred from the β-Trp37 residue at the α1β2 interface of the protein to the dye. Proflavine induced significant secondary structural changes in Hgb. Synchronous fluorescence studies showed that proflavine altered the microenvironment around the tryptophan residues to a greater extent than the tyrosine residues. Circular dichroism spectral studies showed that proflavine caused significant reduction in the α-helical content of Hgb. The esterase activity assay further complemented the circular dichroism data. The Soret band intensity of Hgb decreased upon complexation. Differential scanning calorimetry and circular dichroism melting results revealed that proflavine induced destabilization of Hgb. The binding was driven by both positive entropy and negative enthalpy. Atomic force microscopy studies revealed that the essential morphological features of hemoglobin were retained in the presence of proflavine. Overall, insights on the photophysical aspects and energetics of the binding of proflavine with Hgb are presented.
Heat Treatment Influence on the Wear Behaviour of TitaniumMolybdenum Biomedical Alloys
A GHIBAN, A E JIMENEZ BALLESTA, [...], [Talymap]
In present paper there are given the results concerning wear behaviour in Ringer’s solution of four titanium alloys with 5%Mo, 7%Mo, 11%Mo and 12%Mo. Structural investigations (made by both optic, electronic
microscopy and X-Rays diffraction) revealed a dual phase structure consisting from alpha martensite and beta”solid solution, with the constituents proportion depending on molybdenum content. Wear rates were determined using a Talysurf profilometer in Ringer’s solution for the experimental titanium-molybdenum
alloys. Finally, the beneficial influence of molybdenum on wear behavior was put in evidence: the higher molybdenum content is, the lower friction coefficient is.
Effect of orthodontic debonding and residual adhesive removal on 3D enamel microroughness
J JANISZEWSKA-OLSZOWSKA, R TOMKOWSKI, [...], [Talymap]
Termination of fixed orthodontic treatment is associated with bracket debonding and residual adhesive removal. These procedures increase enamel roughness to a degree that should depend on the tool used. Enamel roughening may be associated with bacterial retention and staining. However, a very limited data exists on the alteration of 3D enamel roughness resulting from the use of different tools for orthodontic clean-up. Aims: 1. To perform a precise assessment of 3D enamel surface roughness resulting from residual adhesive removal following orthodontic debonding molar tubes. 2. To compare enamel surfaces resulting from the use of tungsten carbide bur, a one-step polisher and finisher and Adhesive Residue Remover. Material and Methods: Buccal surfaces of forty-five extracted human third molars were analysed using a confocal laser microscope at the magnification of 1080× and 3D roughness parameters were calculated. After 20 s etching, molar tubes were bonded, the teeth were stored in 0.9% saline solution for 24 hours and debonded. Residual adhesive was removed using in fifteen specimen each: a twelve-fluted tungsten carbide bur, a one-step finisher and polisher and Adhesive Residue Remover. Then, surface roughness analysis was repeated. Data normality was assessed using Shapiro–Wilk test. Analysis of variance (ANOVA) was used to compare between variables of normal distribution and for the latter—Kruskal-Wallis test.
[PDF] Analysis of Machinable Structures and Their Wettability of Rotary Ultrasonic
Texturing Method
S XU, K SHIMADA, M MIZUTANI, T KURIYAGAWA, Chinese J Mechanical Eng, [Talymap]
Tailored surface textures at the micro- or nanoscale dimensions are widely used to get required functional performances. Rotary ultrasonic texturing (RUT) technique has been proved to be capable of fabricating periodic micro- and nanostructures. In the present study, diamond tools with geometrically defined cutting edges were designed for fabricating different types of tailored surface textures using the RUT method. Surface generation mechanisms and machinable structures of the RUT process are analyzed and simulated with a 3D-CAD program. Textured surfaces generated by using a triangular pyramid cutting tip are constructed. Different textural patterns from several micrometers to several tens of micrometers with few burrs were successfully fabricated, which proved that tools with a proper two-rake-face design are capable of removing cutting chips efficiently along a sinusoidal cutting locus in the RUT process. Technical applications of the textured surfaces are also discussed. Wetting properties of textured aluminum surfaces were evaluated by combining the test of surface roughness features. The results show that the real surface area of the textured aluminum surfaces almost doubled by comparing with that of a flat surface, and anisotropic wetting properties were obtained due to the obvious directional textural features.
pH-controlled drug release of radiation synthesized graphene oxide/(acrylic acid-co-sodium alginate) interpenetrating network
A I RAAFAT, Polymer Bulletin, [PicoImage]
Hydrogel biocomposites containing a combination of graphene oxide (GO) and natural polymer-based copolymer of sodium alginate (Alg) and acrylic acid (AAc) were prepared by radiation-induced copolymerization and crosslinking. FTIR, XRD, and AFM analyses revealed the successful preparation of single-layered graphene oxide sheets. FTIR and TGA data confirmed the incorporation of GO within the (AAc-co-Alg) copolymer hydrogel. The effect of GO content, as interpenetrating network, on the swelling behavior of (AAc-co-Alg) copolymer hydrogel was investigated. The results of the pH-dependent swelling showed the presence of GO within the prepared hydrogel improve the ability of the GO/(AAc-co-Alg) nanocomposite hydrogel to bypass the acidity of the simulated stomach medium (pH 1) without significant swelling and regulate it for longer period in simulated intestine medium (pH 7). Moreover, the swelling kinetics showed that all the samples under investigation possess Fickian at pH 1 and non-Fickian at pH 7. The evaluation of the prepared GO/(AAc-co-Alg) nanocomposite hydrogel as drug carrier was carried out in either simulated stomach and intestine media using cefadroxil as a model drug. The drug release profile came in a good agreement with swelling results which recommend the GO/(AAc-co-Alg) nanocomposite hydrogel as potential targeted drug delivery system.
Variation in taper surface roughness for a single design effects the wear rate in total hip arthroplasty
R WHITTAKER, H S HOTHI, [...], J Orthopeadics Research, [Talymap]
Material loss from the head-stem taper junction of total hip arthroplasty (THA) is implicated in adverse reactions to metal debris (ARMD); the mechanisms for this are multi-factorial. We investigated the relationship between the roughness of the “as manufactured” taper surface and the wear rate from this junction. Fifty retrieved Pinnacle metal-on-metal (MOM) bearings paired with a Corail stem were included in the study. Multivariable statistical analysis was performed to determine the influence of taper roughness on material loss rate after controlling for other confounding surgical, implant, and patient factors. The surface roughness of the “as manufactured” head taper surface was associated with the rate of material loss from this surface. Four of eighteen roughness variables taken from ISO 4,287 and ISO 13,565-2 were significant: The Reduced Peak Height (Rpk, the protruding peaks above the core) (p = 0.004), Material Ratio 1 (Mr1, the ratio of the protruding peaks above the core) (p = 0.002), Area of the Peak Region (A1, the area of the Abbott-Curve that contains the peaks from the profile) (p = 0.003) and the Skewness (Rsk, the asymmetry of the height distribution corresponding to the height or depth of surface features) (p = 0.03). We found a large variability in the measured values with a median (range) of 0.50 (0.05–2.98), 11.98 (0.46–39.98), 30.89 (0.15–581.00), and 0.04 (−0.73–0.84), respectively. A 1-unit increase in Rpk was associated with a 73% increase in the taper wear rate. The variability of “as manufactured” surface roughness has a significant effect on taper material loss.
Detailed Analysis of Random Pyramid Surfaces With Ray Tracing and Image Processing
H MÄCKEL, H HOLST, [...], IEEE J Photovoltaics, [MountainsMap]
For the optimization of alkaline texturing in industrial monocrystalline silicon solar cells, it is of paramount importance to understand the correlation between surface reflectance and surface morphology. In this study, the reflectance is related to the surface geometry using image processing and ray tracing. Surfaces with a variation of random pyramid texturing were scanned with laser scanning microscopy. The resulting height maps were either directly used as input for the ray tracing or used as a template for a synthetic height map. A procedure was developed to extract an effective pyramid base angle from the images. It takes on values from 47.9° to 54.3°, which are below the {111} pyramid base angle of 54.74°. The reflectance decreases linearly with the effective base angle and the pyramid height. Ray tracing of as-measured and reconstructed height maps with ideal pyramid base angle shows that both are a poor representation of the pyramid landscape. The best fit between measured and simulated reflectance is obtained when the effective base angle is used to reconstruct the surface. The surface with lowest reflectance is characterized by pyramids with high base angle and large size.
Surface modification of mild steel using a combination of laser and electrochemical processes
A SPEIDEL, A H A LUTEY, [...], Surface and Coatings Tech, [MountainsMap]
Traditional methods for achieving hierarchical surface structures include highly specified, deterministic approaches to create features to meet design intention. In this study microstructural alteration was undertaken using laser apparatus and secondary texturing was achieved via succeeding electrochemical processes. Electrochemical jet machining (EJM) was performed on mild steel subjected to laser pre-treatment using power densities of 4167 and 5556 W/cm2 with pulse durations from 0.3–1.5 s. Results show that in combination, laser pre-treatment and EJM can alter the exposed surface textures and chemistries. Here, machined surface roughness (Sa) was shown to increase from approximately 0.45 μm for untreated surfaces to approximately 18 μm for surfaces subjected to extreme laser pre-treatments. After pre-treatments materials were characterised to appraise microstructural changes, shown to be martensite formation, reinforced by complementary simulation data, and significant increases in observable hardness from approximately 261 HV for the as-received material to over 700 HV after pre-treatment. The greater hardness was retained after EJM. Exposed martensitic lath structures at machined surfaces are shown to be partially responsible for surface roughness increases. The surfaces were explored with energy dispersive X-ray spectroscopy (EDS) and Raman spectroscopy demonstrating changes in apparent surface chemistry. This analysis revealed increasing oxide formation at the surface of the pre-treated EJM surface, a further contributory factor to surface roughness increases. This new process chain will be of interest to manufacturers seeking to control surface morphology for applications including micro-injection mould/die manufacture. While demonstrated here for steel similar mechanisms are exploitable in other material systems. A new technique has been demonstrated, resulting from the models and processes presented to couple laser and electrolyte jet processing for complex surface preparation.
Shape descriptors and statistical classification on areal topography data for tile inspection in tessellated surfaces
N SENIN, M MORETTI, R K LEACH, Measurement, [MountainsMap]
Verification of conformance to design specifications in production, and identification of defects related to wear or other damage during maintenance, are key metrological aspects that must be addressed for micro-scale tessellated surfaces. A new algorithmic approach is presented that operates on topography datasets as obtained by areal topography instruments. The approach combines segmentation algorithms with a novel implementation of the angular radial transform, originally adopted by the MPEG-7 standard, to implement shape descriptors and associated similarity metrics. Applications to the inspection and verification of laser-manufactured micro-embossing topographies are illustrated. The topographies are first segmented to extract the individual tiles; the tiles are then encoded through shape descriptors. Principal component analysis and cluster analysis are used to investigate the behaviour of the angular radial transform coefficients. Finally, an algorithmic classifier based on supervised learning (k-nearest neighbours) is implemented and shown to be effective at identifying defects and at discriminating between defect types.
Sol-gel synthesis, characterization and properties of TiO2 and Ag-TiO2 coatings on titanium substrate
N COTOLAN, M RAK, [...], Surface and Coatings Tech, [Talymap]
The aim of this study is the sol-gel synthesis of TiO2 and Ag-TiO2 coatings which would provide corrosion resistance and reduce bacterial adhesion when deposited on titanium substrate. The molar ratios of AgNO3:H2O2:TiO2 were 0.0037:2:1. The composition of the sols was checked using UV/Vis spectroscopy. The properties of the obtained coatings were investigated using X-ray diffraction, scanning electron microscopy with chemical analysis, and 3D profilometry. Electrochemical studies were performed in a simulated physiological solution and demonstrated good protection of the TiO2 and Ag-TiO2 coatings for the titanium substrate. Dissolution of silver from the coating was qualitatively followed by electrochemical impedance spectroscopy. The adhesion of Pseudomonas aeruginosa as a biofilm forming bacteria commonly found in orthopaedic applications was reduced in the presence of silver and the bacteria shape destroyed. No cytotoxicity of the coatings on human osteoblastoma cells was noticed. Our results suggest that TiO2 and Ag-TiO2 coatings obtained by a green synthesis sol-gel route at low temperature can be tailored to offer properties suitable for biomedical applications.
Reconstructing method of nonlinear dynamic surfaces
V KHOMA, W P HUNEK, A KHOMA, [Talymap]
In this paper reconstructing method of spherical and variable in time surface based on estimation of the instantaneous values phase with imaginary part of complex white light interferogram logarithm is presented. An accuracy analysis of the above-mentioned method in terms of reconstruction of spherical surface is done here. The methodology of research concerns the synthesis of surface through the mathematical model of interferogram as well as an estimate the error of profile reconstruction. The effectiveness of the method is verified through the reconstruction of surface obtained from interferogram of white light under monitoring the pressure sensor membrane.
Tooth wear as a means to quantify intra-specific variations in diet and chewing movements
I CALANDRA, G LABONNE, E SCHULZ-KORNAS, T KAISER, S MONTUIRE, Nature, [MountainsMap]
In mammals, tooth function, and its efficiency, depends both on the mechanical properties of the food and on chewing dynamics. These aspects have rarely been studied in combination and/or at the intra-specific level. Here we applied 3D dental surface texture analysis to a sample of field voles (Microtus agrestis) trapped from Finnish Lapland at different seasons and localities to test for inter-population variations. We also explored intra-individual variation in chewing dynamics by analysing two facets on the second upper molars. Our results confirm that the two localities have similar environments and that the voles feed on the same items there. On the other hand, the texture data suggest that diets are seasonally variable, probably due to varying concentrations of abrasives. Lastly, the textures on the buccal facets are more isotropic and their direction deviates more from the mesial chewing direction than the lingual facets. We interpret these results as reflecting food, rather than chewing, movements, where food particles are more guided on the lingual side of the molars. This has implications for the application of dental microwear analysis to fossils: only homologous facets can be compared, even when the molar row seems to constitute a functional unit.
Mechano-electrochemical modelling of corroded steel structures
Y WANG, J A WHARTON, R A SHENOI, Eng Structures, [PicoImage]
A numerical methodology is established to study the mechano-electrochemical performance of corroded steel structures under external and internal stresses. Results show that mechanical stimuli (elastic/plastic deformation) increase the local anodic current density, and thus the corrosion behavior dynamically responds to the loading conditions. The current density increment for a multi-component stress system is largely dependent on both hydrostatic pressure and equivalent plastic strain. Moreover, the mechano-electrochemical corrosion is more affected by plastic deformation, resulting in localized areas being more anodic. Existing corrosion introduces extra stress/strain concentration, which further reduces the structural strength capacity and intensifies the corrosion damage.
Reactive Copolymers Based on N-Vinyl Lactams with Pyridyl Disulfide Side Groups via RAFT Polymerization and Postmodification via Thiol–Disulfide Exchange Reaction
H PENG, K RÜBSAM, [...], Macromolecules, [PicoImage]
Herein, we report the synthesis of a series of novel pyridyl disulfide (PDS)-functionalized statistical reactive copolymers that enable facile access to complex polymeric architectures through highly selective thiol–disulfide exchange reaction with thiol-containing ligands or proteins. The PDS contents in the synthesized copolymers were varied from 2 to 10 mol % (as confirmed by systematical characterization with FTIR/Raman and 1H NMR spectroscopy) using well-controlled continuous feeding method. The kinetics study suggested that copolymerizations were less favored with the enlargement of the lactam rings, indicated by lower conversions and larger dispersity indexes (Đ). The PDS-functionalized reactive polymers were amenable to functionalization with a variety of thiol-containing molecules, including 3-mercaptopropionic acid (3M), 2-phenylethanethiol (2P), methyl 3-mercaptopropionate (M3), 2-mercaptoethanol (2M), 2-aminoethanethiol (2A), poly(ethylene glycol) methyl ether thiol (PEG-SH), and enhanced green fluorescent protein (EGFP) via thiol–disulfide exchange reaction under mild conditions, confirmed by 1H NMR and SDS-PAGE. The conversions in all cases were higher than 95%, displaying that the thiol–disulfide exchange reaction to PDS groups with thiol-containing molecules is highly selective and tolerant to different ligands including amine, carboxyl, hydroxyl, phenyl, PEG and even polypeptides, providing a versatile scaffold for facile conjugation of various biological components. The contact angle measurement results and fluorescence microscopy study indicated that the reactive films based on the PDS-functionalized copolymers allowed facile, direct, and environmental-friendly surface engineering of surfaces from aqueous solution suggesting potential application in surface decoration of tissue-engineering scaffolds and medical implants. The initial cell culture experiments with HeLa cells displayed that the unmodified PVPD film was nontoxic and biocompatible while the film modified with PEG (a type of antifouling polymer) showed diminished cell attachment and growth, indicating that elegant engineering of the film surface can meet demands of particular applications.
The effects of DC power on the physical properties and surface topography of sputtered TiN nanostructured thin films
N GHOBADI, M GANJI, [...], Optical and Quantum Electronics, [MountainsMap]
Four high quality nanostructured thin films of titanium nitride, with thicknesses equal to 81, 325, 485 and 565 nm respectively, were deposited on glass substrates by the reactive magnetron sputtering method using different DC power values (from 200 to 410 W). The results revealed that the DC power plays a crucial role in the evolution of the thickness, topography, microstructure, optical and semiconducting properties of the resulting thin films. Specifically, an increase in the DC power enhances the crystalline order of the samples, consequently; the energy band gap values and the electrical resistivity decrease. Also, a competitive growth of crystalline planes of different orientations was found as a consequence of the increment of the grain size. In addition, the influence of DC power on the 3-D surface morphology of these thin films was investigated. The largest peak height and also the largest valley depth from the mean surface increased at higher amounts of DC power. The flexible variation of the physical properties of thin films with the simple and reproducible variation of the DC power in the sputtering process could be exploited in the use of these samples in specific technological applications.
Slide diamond burnishing influence on of surface stereometric structure of an AZ91 alloy
M KORZYNSKI, T ZARSKI, Surface and Coatings Tech, [Talymap]
The paper is a study of the surface stereometric structure of AZ91 specimens after slide diamond burnishing using PCD tools. The experimental models describing the influence of the burnishing conditions on Sa and some other non-standard surface parameters were obtained. The results of slide burnishing and those of precise turning were compared by assessing the values of a dozen or so parameters of the surface structure. The correlations between certain surface parameters were revealed. Also, it was established that the application of burnishing makes it possible to achieve a surface roughness of Sa < 0.4 μm as well as good values of many other surface stereometric structure parameters, so this machining process can be used for finishing AZ91 alloy objects.
Anti-biofouling anion exchange membrane using surface modified quaternized poly(ether imide) for microbial fuel cells
M ELANGOVAN, S DHARMALINGAM, J Applied Polymer Sci, [Talymap]
This article deals with a novel way of improving the anti-biofouling potential of an anion exchange membrane (AEM) by surface modification with ethanol amine (AEOH), a low cost material without affecting the chemical structure and morphology of Quaternized Poly(ether imide) (QPEI), the host membrane. The anti-biofouling potential of the AEM was evaluated using bacteria anti-adhesion test, hydrophilicity, surface roughness, water uptake, and the AEOH modification time. The data reveal that power density in all MFCs attain the highest in the sixth batch and thereafter declined albeit in a varying rate as expected measuring the least for QPEI-30. Periodical measurement of internal resistance and protein content on the membrane surfaces were found to be the least for QPEI-30 when compared with others. A reduced biofouling with improved anti-biofouling property is attributed to the enhanced hydrophilicity due to surface modification.
Inkjet printing on transparency films for reagent storage with polyester–toner microdevices
S T KRAUSS, T P REMCHO, [...], Analytical methods, [MountainsMap]
The use of overhead transparencies as substrates for the fabrication of microfluidic devices brings new capabilities in the creation of fully-integrated systems. Here, we describe a reagent storage method through inkjet printing that is complementary to the simple print, cut and laminate (PCL) fabrication technique, which already incorporates printing toner onto commercial off-the-shelf materials for fabrication of polyester–toner microdevices. With the surface of the polyester film dramatically different than paper, substrate optimization was required to increase printability without incorporating additional substrate-coating steps. Functionality for chemical sensing devices, operated centrifugally here, was demonstrated through standard human serum albumin analysis. Quantitative results were obtained through image analysis using a desktop scanner to determine color change in the presence of various total protein and albumin concentrations. Printed devices exhibited a shelf life of at least two months with no loss in activity, resulting in a relative standard deviation of 0.652% for total protein analysis.
Effects of Different Plasma Nitrided Layers on the Tribological Performance of DLC Coatings
P H TESHIMA SHIOGA, C BINDER, [...], Mat Research, [MountainsMap]
When multifunctional surface engineering processes that combine purpose-oriented phases are applied to soft substrates, a combination of high wear resistance, high load support and low coefficients of friction can be achieved. In this study, the effects of different nitrided layers on the tribological behaviour of a diamond-like carbon (DLC) film deposited on a SAE 1040 steel were investigated. The nitriding was carried out under different temperatures and gas mixtures to create three distinct nitrided layers: two compound layers with predominant ε and γ' phases and a diffusion layer. All of the surfaces were then coated with DLC deposited via plasma-enhanced chemical vapour deposition (PECVD). The tribological tests indicated that the best performance was achieved for a specific combination of hardness, surface roughness and nitride type. The best load-bearing capacity between the DLC coating and the soft substrate was achieved when the nitrided layer was primarily a diffusion layer.
Shallow-generated damage within non-planar strike-slip fault zones: role of sedimentary rocks in slip accommodation, SW Holy Cross Mountains, Poland
B RYBAK-OSTROWSKA, A KONON, [...], Int J Earth Sci, [HommelMap]
We investigated exhumed damage zones of dextral strike-slip faults dissecting the south-western part of the Mesozoic cover of the Late Palaeozoic Holy Cross Mountains Fold Belt. Structural observations allow to examine the top 1–2 km of the fault zones that deformed asymmetrically with the most intense damage controlled by the non-planar geometry of the faults. The deformational style of fault zones and the roughness of slip surfaces on subsidiary faults within deflections of fault traces in the restraining and releasing bends were facilitated by rock fabric and porosity. High porous sandstones enhanced genesis of cataclastic shear bands within the damage zone and the smooth slip surfaces. Low porous limestones enhanced the formation of dilatant structures infilled with calcite within damage zones and rough slip surfaces. The complex structural pattern of damage zones records multiple episodes of slip and shows evidence of continuous seismic–aseismic modes of fault slip behaviour.
The effect of polyethylene glycol-modified lipids on the interaction of HIV-1 derived peptide–dendrimer complexes with lipid membranes
S MELIKISHVILI, A POTURNAYOVA, [...], Biochimica et Biophysica Acta - Biomembranes, [PicoImage]
In this study, dendrimers have been purposed as an alternative approach for delivery of HIV peptides to dendritic cells. We have investigated the interaction of dendriplexes formed from polyanionic HIV peptide Nef and cationic carbosilane dendrimer (CBD) with model lipid membranes — large unilamellar vesicles (LUVs), Langmuir monolayers and supported lipid membranes (sBLMs) containing various molar ratio of zwitterionic 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC) and 1,2-distearoyl-sn-glycero-3-phosphoethanolamine-N-[methoxy (polyethylene glycol)-2000] (DSPE-PEG2000). In our experiments, the lipid membranes represented the model of the plasma membrane of the cell. PEGylated lipids were used in order to model glycocalyx which constitutes the outer leaflet of cellular membranes. The presence of PEGylated lipids resulted in an increase of the phase transition temperature of the lipid bilayer of LUVs, in a decrease of specific volume and adiabatic compressibility. Fluorescence anisotropy study suggests that PEGylated LUVs possessed higher lipid order and decreased fluidity when compared to zwitterionic DMPC vesicles. The interaction of dendriplexes with monolayers was accompanied by the formation of the aggregates as revealed by BAM experiments. This conclusion has been confirmed also by AFM imaging of sBLMs. We have demonstrated that dendriplexes interact with lipid membranes for all types of lipid composition. Moreover, the stronger interaction of cationic dendrimer/peptide complexes with lipid monolayers, vesicles and sBLMs was observed for membranes composed of zwitterionic lipids than for PEGylated lipid membranes. Increased concentration of PEGylated lipids made this interaction weaker.
[PDF] Rapid Prototyping of Polymer Waveguides by Contour Shaping
S SCHRÖDER, C MÜLLER, DGaO Proc, [MountainsMap]
We present a novel method for manufacturing polymer waveguides. The main part is the structuring of the grooves by ultra-precision shaping. Afterwards the grooves are poured with a UV-sensitive core polymer, covered and cured. We demonstrated that ultra-precision shaping enables mechanical micro structuring for rapid prototyping of optical components and in higher lot sizes the possibility of making a replication step obsolete.
Temperature-responsive properties of poly(4-vinylpyridine) coatings: influence of temperature on the wettability, morphology, and protein adsorption
J RACZKOWSKA, Y STETSYSHYN, [...], RSC Advances, [PicoImage]
Although the pH-response of poly(vinylpyridine)-based systems is well-known and indeed used in several biomedical applications, the impact of temperature on the properties of this polymer has not been investigated in detail so far. Herein, we demonstrate the temperature-responsiveness and switchable wettability of two poly(4-vinylpyridine) coatings, mimicking the behavior of materials with lower critical solution temperature. The thermal response of P4VP spin-coated films, solvent cast on a glass, is weaker than that observed for P4VP-grafted brushes, fabricated via polymerization from an oligoperoxide grafted on an amino-silanized glass. Both the P4VP coatings exhibit a temperature dependence of the water contact angle with a well-defined transition at 13–14 °C. This transition is absent at acid pH levels wherein almost all pyridyl groups are protonated. The P4VP-grafted brushes were used to examine the impact of temperature on the surface morphology and protein adsorption. The coating surface, recorded with atomic force microscopy, evolved noticeably at alkaline pH, from being relatively smooth at 10 °C to structured and rough at 20 °C. In turn, at acid pH levels, flat surfaces with rare elevations were observed at both temperatures. The adsorption of bovine serum albumin and human fibrinogen was observed with fluorescence microscopy to be significantly more efficient for temperatures above the transition, indicating that P4VP coatings can act as a noteworthy switching material.
Durability performance of eco-friendly ductile cementitious composite (EDCC) as a repair material
YANG D, Master's thesis, Univ British Columbia, [MountainsMap]
The objective of the experimental program in this thesis is to investigate the durability performance of Eco-friendly ductile cementitious composite (EDCC), a newly developed repair material for seismic retrofitting. Several aspects of the durability performance of EDCC were investigated in this work, in terms of restrained shrinkage resistance, freeze and thaw resistance and bond strength degradation before and after environmental exposure. All the tests focused on repair overlay and substrate
composite assembly. Six different EDCC fiber mixes were involved in the testing to discover the best mix in terms of performance and economical aspects. The substrate of the composite assembly includes concrete, masonry blocks and clay blocks. EDCC can be applied on different substrates by hand casting and spraying. EDCC application on concrete substrates employing the
hand casting process is used to explore the durability performance of EDCC. Clay and masonry substrates, along with the spray application process, are only used to compare the influence of different application methods on the bond strength based on the bond strength data obtained in Yuan Yan's thesis.
Surface morphology analysis of Duplex Stainless Steel (DSS) in Clean Production using the Power Spectral Density
KROLCZYK G M, MARUDA R W, NIESLONY P, WIECZOROWSKI M, Measurement, 94, [MountainsMap]
The paper analyses the influence of clean manufacturing (green manufacturing) methods on the surface morphology of duplex stainless steel. The surface quality was compared using Power Spectral Density for dry and MQCL turning process. Analysis of signal power on the surface demonstrated that the wavelength is higher for dry turning than for machining using MQCL method. The amplitude of the feed ingredient is visible in the higher range of the feed, at low feed rates dominate tool vibration with the wear of the cutting tool point. In the paper the authors proved that using PSD it is possible to characterize turning regarding applied cooling methods, by qualitative and quantitative comparison of this function for inspected surfaces. Additionally amplitudes of analyzed surfaces are approximately from 1.81 μm to 2.10 μm for different feed values.
Probing the binding of anticancer drug topotecan with human hemoglobin: Structural and thermodynamic studies
KHAN A Y, KUMAR G S, J Photochemistry and photobiology B, 163, [PicoImage]
Protein - ligand interactions play pivotal role in almost all the biological processes occurring in living organisms, and therefore such studies hold immense importance from the standpoint of rational drug design and development. In this study the binding of the topoisomerase I inhibitor drug, topotecan to hemoglobin was probed using various biophysical and microcalorimetry techniques. Spectrofluorimetric data confirmed the static nature of the quenching mechanism of the protein induced by the drug. Significant conformational changes in the protein were ascertained from circular dichroism and three dimensional fluorescence results. Synchronous fluorescence study revealed an increase in the polarity around the Trp residues of the protein while atomic force microscopy study enabled to obtain images of the bound molecules. Isothermal titration calorimetry studies indicated an exothermic binding with a negative Gibbs energy change; ionic strength variation suggested a greater contribution from non-polyelectrolytic forces in the binding process. Differential scanning calorimetry studies indicated an increased thermal stabilization of the protein upon topotecan binding which is also in close agreement with the results obtained from absorbance and circular dichroism melting studies. Overall this manuscript presents results on the molecular interaction from structural and energetic perspectives providing an in depth insight into drug-protein interaction.
Orientation and biorecognition of immunoglobulin adsorbed on spin-cast poly(3-alkylthiophenes): Impact of polymer film crystallinity
AWSIUK K, BUDKOWSKI A, [...], Colloids and Surfaces B, [PicoImage]
Many of bioelectronic and biosensor applications are based on poly(3-alkylthiophenes), conducting and solution-processable polymers. The most facile approach for the fabrication of such devices relies on biofunctionalization of P3AT surfaces with antibodies through adsorption. The success of this approach depends critically on antibody orientation that affects its biorecognition. As demonstrated here both these features are controlled by the surface structure of spin-cast P3ATs. In particular, a multi-technique and multivariate study that involved Atomic Force Microscopy, Grazing Incidence X-ray Diffraction, Angle-Resolved X-ray Photoelectron Spectroscopy, Enzyme-Linked ImmunoSorbent Assay, and Time-of-Flight Secondary Ion Mass Spectrometry combined with Principal Component Analysis is conducted in order to deduce the crystalline texture of three P3AT polymers as well as its effect on orientation of adsorbed rabbit immunoglobulin (IgG) molecules. An edge-on crystalline texture is concluded for regioregular poly(3-butylthiophene) (RP3BT) and poly(3-hexylthiophene) (RP3HT), while amorphous morphology is inferred for poly(3-butylthiophene) (P3BT). In addition, end-on and head-on orientations similar for all P3ATs were concluded, based on the amount of adsorbed rabbit IgG molecules. Examination of amino acids characteristic for F(ab’)2 and Fc fragments, and dominant in the external regions of adsorbed immunoglobulin molecules, points to end-on IgG alignment on RP3BT and RP3HT, but not on P3BT. Moreover, the binding of an anti-rabbit IgG antibody on the absorbed rabbit IgG is higher (up to 71%) when the biorecognition reactions are performed on regioregular rather than regiorandom P3AT surfaces. In particular, the highest biorecognition efficiency and IgG orientational order is observed for the RP3BT surfaces with the more developed crystallinity.
Metal–Polymer Hybrid Architectures as Novel Anode Platform for Microbial Electrochemical Technologies
BAUDLER A, LANGNER M, [...], Chem Sus, [LeicaMap]
In this publication, we propose metal–polymer hybrid materials as a novel platform for the development of 3 D anode materials for bioelectrochemical systems, such as microbial fuel cells. Extremely low gravimetric density, high porosity, high electric conductivity, and distinct elastic properties are characteristics that are superior for bioelectrochemical applications. As a proof of concept, we investigated copper-melamine foams (Cu-MF) based on a commercially available, open cell melamine foam. With a low amount of copper (16.3 mg cm−3 for Cu-MF206) used for metallization, such electrode material can be manufactured at low price. The Cu-MF sponges are readily colonized by electrochemically active bacteria and are electrochemically stable over an experimental period of more than 75 days. The Cu-MF-biofilm electrodes exhibit volumetric current densities of up to 15.5 mA cm−3. During long-term operation, overgrowth of the Cu-MF pore structures by the Geobacter-dominated biofilms occurs, from which demands for future electrode developments are derived.
Environmental Effects on Cartridge Case Primer Shear Marks
POLLUT S, DIACZUK P, [...], Forensic Sci J, [MountainsMap]
In order to address the scarcity of publications dealing with the comparison of cartridge cases subjected to environmental exposure, this pilot study investigated how the surface features of fired cartridge cases were affected when exposed to a moist environment over well defined periods of time. The primer shear marks of 25 (9mm) Remington 115 grain brass metal cartridge cases fired from a Glock 19 were examined. Five of these cases were not exposed (time = 0) to the environment so they could serve as control templates. All were viewed under a comparison microscope prior to exposure to confirm that the firearm was making reproducible marks on the primers. The cases were buried in a sun exposed forested plot in northeastern New Jersey (USA) during the summer months and analyzed at intervals of three, six, nine, and twelve weeks. The retrieved cases were examined once again with a comparison microscope. All buried cases were still capable of being matched with the unburied control cases despite some visible wear. Further examination with confocal microscopy was performed, in which 30 different surface parameters were measured. One-way Analysis of Variance (ANOVA) was applied to the mean surface parameters to determine if environmental exposure over time contributed significantly to observed variability (a rejection of the null hypothesis). All but one of the 30 parameter mean values met the 5% confidence level. The outlier value “Ssk” (p-value= 0.004), a height parameter which measures skewness of the height distribution, was further analyzed with the post hoc test Tukey HSD. It identified the comparison between the unburied case with the three week interval buried case as the source of the low probability (under 0.05).
Performance of a Magnesium-Rich Primer on Pretreated AA2024-T351 in Selected Laboratory and Field Environments: Conversion Coating Pretreatments
KANNAN B, SCULLY J R, Corrosion, 72(11), [MountainsMap]
The effect of conversion coatings on the corrosion protection of AA2024-T351 by magnesium-rich primer (MgRP) was evaluated in topcoated and non-topcoated, scribed conditions. Protection of remote scratches and global protection by the coating after exposure in selected laboratory and field environments was investigated. Exposure studies focused on chromate conversion coating, trivalent chromium pretreatment (TCP), and non-chromium pretreatment, and compared to non-film forming (NFF) surface pretreatment. Exposures were conducted in the field under two different environments: at a coastal marine site and at an inland rural site. ASTM B117 with 5 wt% NaCl, modified ASTM B117 with acidified ASTM substitute ocean water and UV light, as well as full immersion in ambiently aerated 5 wt% NaCl solution were compared to field environments. Mg pigment depletion rate, global galvanic protection potential, coating barrier properties, and scribe protection were investigated. In systems without a topcoat, full immersion studies resulted in significant depletion of Mg, and all other environments led to depletion of Mg at different rates. In contrast, a polyurethane topcoat limited the Mg metallic pigment depletion, resulting in only partial Mg depletion in all chosen environments. [...]
Ultrafast Epitaxial Growth Kinetics in Functional Oxide Thin Films Grown by Pulsed Laser Annealing of Chemical Solutions
QUERALTO A, PEREZ DEL PINO A, [...], Chem Mater, 28(17), [MountainsMap]
The crystallization process and physical properties of different functional oxide thin films (Ce0.9Zr0.1O2-y, LaNiO3, Ba0.8Sr0.2TiO3, and La0.7Sr0.3MnO3) on single crystal substrates (Y2O3:ZrO2, LaAlO3, and SrTiO3) are studied by pulsed laser annealing (PLA). A Nd:YAG laser source (λ = 266 nm, 10 Hz and τ 3 ns) is employed to crystallize chemical solution deposited (CSD) amorphous/nanocrystalline films under atmospheric conditions. We provide new insight on the influence of photochemical and photothermal interactions on the epitaxial crystallization kinetics of oxide thin films during the transformation from amorphous/polycrystalline material (i.e., atomic diffusion, epitaxial growth rates, and activation energies of nucleation and crystallization). The epitaxial growth is investigated by varying the laser fluence and the applied number of pulses. The morphology, structure, and epitaxial evolution of films are evaluated by means of atomic force and transmission electron microscopies and X-ray diffraction. Highly epitaxial oriented films of 20–40 nm in thickness are obtained by PLA. The crystallization kinetics of laser treatments is determined to be orders of magnitude faster than thermal treatments with similar activation energies (1.5–4.1 eV), mainly due to the large temperature gradients inducing modified atomic diffusion mechanisms derived mainly from photothermal interactions, as well as a minor contribution of photochemical effects. The fast heating rates achieved by PLA also contribute to the fast epitaxial growth due to reduced coarsening of polycrystalline material. The measurement of the physical properties (electrical resistivity and magnetism) of laser processed CSD films has revealed significantly good functionalities, close to those of thermally grown films, but with much shorter processing times.
Quantification of cylinder bores almost ‘zero-wear’
OBARA R B, SINATORA A, Wear 364-365, [Talymap]
Despite the importance of wear evaluation during initial stages of engine life, low wear rates require the use of very accurate measurement techniques. Topography analysis has been widely used to evaluate almost ‘zero-wear’; however, the lack of uniformity in the determination of a reference height for comparison between worn and unworn surfaces can completely change the results, making them unreliable. In this work, a heavy duty diesel engine was tested in dynamometer during 100 h and relocated topographies were obtained before and after the test. Volume losses were computed by comparing bearing area curves from worn and unworn surfaces using different reference heights. Although most works consider valleys or core as a reference, it is shown that both references can result in underestimation of wear. A new methodology for almost ‘zero-wear’ measurement based on the analysis of bearing area curves is proposed. Additionally, the variation of 3D functional parameters is investigated for evaluation of almost ‘zero-wear’.
Shaping the surface texture of the ring-type test samples used for evaluation of the surface roughness by ARS method based on imaging and analysis of the scattered light
KLAPONEK W, NADOLNY K, UNGUREANU N, Int J Prec Eng, 6(2),[HommelMap, Talymap]
Determining the metrological parameters of a newly developed measurement system often requires conducting proper test procedures, using typical commercial or specifically dedicated standards, alongside test samples. This paper presents the various stages in the preparation and measurement of ring-type test samples prepared for the testing of hybrid systems for non-contact simultaneous assessment of surface texture and dimension. Machining of the samples was carried out using a small bench-type SK-1 lathe, whereas the finishing process using a wide range of abrasive sheets (grain Nos. 200-2500) as well as micro-abrasive (diamond) and polishing (Al2O3-based) pastes. The effects of machining were verified by stylus profilometry and white-light interferometry. All measurement data obtained was analysed by TalyMap Platinum 4.0 software. The results of the analysis confirmed the appropriateness of machining in accordance with the key assumptions made at the design stage. The presented methodology could be helpful during production of non-conventional test surfaces.
Multilayers of poly(styrene/α-tert-butoxy-ω-vinylbenzyl-polyglycidol) microspheres with core-shell morphology: Characterization by AFM, SIMS and XPS
GOSECKA M, RACZKOWSKA J, [...], Colloids and Surfaces A, [PicoImage]
The methods of preparation and characterization of core-shell poly(styrene/α-tert-butoxy-ω-vinylbenzyl-polyglycidol) particles arranged in colloidal crystals are described. The particles were prepared via emulsifier free emulsion copolymerization of styrene and α-tert-butoxy-ω-vinylbenzyl-polyglycidol macromonomer in aqueous medium, initiated by potassium persulfate. The individual polymerizations differed in a way of addition of macromonomer to the polymerization mixture. The particles assemblies were characterized by atomic force microscopy, Secondary Ion Mass Spectrometry (SIMS) and X-ray Photoelectron Spectroscopy (XPS). In-depth distribution of chemical states was determined by XPS combined with argon gas cluster ion sputtering (Ar-GCIB). The morphology of microspheres assemblies reflected the composition of the entire particles. It was found that the method of macromonomer addition to the polymerization mixture affects the particles size, surface and overall morphology. The XPS profiles revealed the chemical composition of the particles arranged in multilayers. It was found that distribution of polyglycidol segments at the particles interfacial layer depends on the time and way of addition of macromonomer. The thickest outer layer composed from polystyrene-polyglycidol segments was obtained for particles when macromonomer was added at the beginning of polymerization.
Cereal cultivation and domestication as shown by microtexture analysis of sickle gloss through confocal microscopy
IBANEZ J J, ANDERSON P C, [...], J Archeological Science, 73, [SensoMap]
When and where cereal cultivation and domestication took place in the Near East are still matters of debate. This quantitative analysis, using confocal microscopy to study “sickle gloss” texture on flint tools used for cereal harvesting, shows that wild cereals were most probably cultivated during the 13th millennium BP in the Middle Euphrates. At that moment, a local and continuous process of cereal domestication began to unfold in this region of the Northern Levant, lasting for over 3 millennia and culminating at the end of the 10th millennium BP. Thus, our research provides a new method for investigating the origins of agriculture, while the data gathered allow us to support the hypothesis of early cereal cultivation during the Younger Dryas and the protracted model of plant domestication, pointing to the Middle Euphrates as one region where this process occurred.
The influence of confining stress on optimum spacing of TBM cutters for cutting granite
LIU J, CAO P, HAN D, Int J Rock mechanics and mining sciences, 88, [Talymap]
Two series of indentation tests on a triaxial testing machine with groove morphology measurement were conducted to investigate the effect of confining stresses on the optimal spacing among TBM cutter indentations. In the first series of indentation tests, over breaking, moderate breakages that resulted from effective fracture interactions and insufficient breaking between indentations were encountered with the increase in spacing. An analysis on the groove volumes and consumed energy indicates that longer spacing is favorable when the differential stress increases, whereas the opposite occurs when the differential stress decreases. To confirm these conclusions, another series of indentation tests was conducted for the spacing and indentation depth of 70 mm and 6 mm, respectively. The results show that the fiercer propagation of surface cracks and more effective connections of the internal cracks are responsible for the elongated optimal spacing when the differential stress increases; the optimal spacing is shortened because of the restrained surface propagation by decreasing the differential stress.
Single-cell analysis of the disruption of bacteria with a high-pressure jet device: An application of atomic force microscopy
XIE L, BAO Q, TERADA A, HOSOMI M, Chem Eng J, 306, [PicoImage]
The goal of this study was to reveal the mechanism of bacterial cell disruption by a high-pressure jet device (HPJD) for the reduction of excess sludge produced during wastewater treatment. Escherichia coli and Bacillus subtilis, representative Gram-negative and Gram-positive bacteria respectively, were subjected to HPJD treatment followed by observation of the damaged cells with epifluorescence microscopy and atomic force microscopy (AFM), as well as spectrophotometric quantification of the released intracellular polymeric compounds. The AFM observations demonstrated that the types of cell damage incurred by E. coli and B. subtilis were distinct. B. subtilis showed modest cell disruption comprising partial damage, i.e., the formation of pores and cracks on the cell envelope. In contrast, E. coli showed more extensive damage, i.e., cell cleavage and lysis, in addition to the partial damages observed for B. subtilis. The damaged cells of both bacterial species also exhibited leakage of intercellular compounds such as DNA, proteins and polysaccharides. This loss of intracellular macromolecules resulted in increased cell surface roughness and decreased cell diameter and elasticity, irrespective of the bacterial species tested. The results demonstrated that the degree of cell damage inflicted by HPJD treatment is dependent on the cell wall and membrane structure of the bacterial species. In summary, we propose multiple possible mechanisms of cell disruption resulting from HPJD treatment.
Comparative assessment of the mechanical and electromagnetic surfaces of explosively clad Ti–steel plates after drilling process
NIESLONY P, KROLCZYK G M, [...], Precision Engineering, 47, [MountainsMap]
The present work pertains to the analysis of surface topography of explosively clad material such as titanium plated steel in drilling process. The study was conducted for different types of indexable insert drills with different configuration of the tool coatings and for WC-Co drill tool. In this context, surface topography of the drilled holes especially in the region of contact area was analyzed. Metrological analysis was performed using stylus-based and optical profilometry. In this paper the differences between mechanically and electromagnetically measured surfaces are highlighted. It has been observed that the parameters of the surface topography are dependent upon the type of layers of the clad and the type of drill.
The effect of oxide scale roughness on the plasticity of iron aluminide alloy
KUPKA M, MARUT J, ANIOTLEK K, BARYLSKI A, Vacuum, 132, [Talymap]
Iron aluminides based on the stoichiometric compositions of Fe3Al and FeAl exhibit poor room temperature ductility due to environmental embrittlement. The embrittling agent is hydrogen liberated from water vapour in contact with an aluminium-rich surface. The formation of Al2O3 oxide scale can act as a barrier retarding the hydrogen penetration from the atmosphere inside the alloy. This barrier effectiveness depends on the scale surface roughness caused by the formation of Al2O3 whiskers. This paper presents a way to suppress the growth of these whiskers. The application of a two-stage isothermal oxidation enabled creating at a lower temperature an intermediate layer, consisting of metastable γ and θ oxides, which contributed to the limitation of α-Al2O3 oxide whiskers growth at a higher temperature and this way to reducing the scale roughness. It has been found that a decreased roughness of scale surface has a favourable influence on iron aluminide plasticity at room temperature.
Investigating the capability of microfocus X-ray computed tomography for areal surface analysis of additively manufactured parts
TOWNSEND A, BLUNT L, BILLS P, [MountainsMap]
The ability to perform non-destructive areal
surface analysis, for example of the internal surfaces of additively manufactured (AM) parts has potential advantages during product
development and for production process control. This paper reports on the extraction of areal surface information from microfocus x-ray computed tomography (XCT) data. Using this novel technique a range of areal parameter
values were generated from a surface section extracted from XCT scan data of an as-built (no post-processing) AlSi10Mg additively manufactured part. This was then compared with the parameter values generated from a focus variation scan of the same surface section. The data comparison method involving normalisation of data format to allow analysis using industry standard
software, such as MountainsMap (Digital Surf, Besançon, France) or SurfStand
(The Centre for Precision Technologies UoH) is demonstrated. Importing the extracted surfaces into these powerful software packages allows one-click data filtering per ISO 25178-3 [1] and the generation of a comprehensive suite of areal surface parameter values. These include feature and field parameters, amplitude, spatial, hybrid and functional parameters, as defined in ISO
25178-2 [2]. A method for characterising the capability of XCT for areal surface measurement is demonstrated by comparing results obtained
from samples taken from a Rubert comparator test panel, with sample surface Ra values between 0.8 μm and 50 μm.
Towards an additive surface atlas
THOMPSON A, SENIN N, [...], [MountainsMap]
There is little doubt that additive manufacturing
(AM) will have a profound effect in many industries, and there are countless examples of polymer products. But, if AM is to be used in earnest in high-value, advanced manufacturing, for example, in the aerospace or medical
industries, then it will be metals and ceramics that will be the game-changers. However, right now, the integrity of metal or ceramic parts
essentially made with powder bed fusion AM processes, is not equivalent to that expected from more conventional manufacturing techniques (casting, forming, machining). AM parts made from metal powders tend to have
high surface roughness values and can suffer from undesired material characteristics (e.g., high porosity or large numbers of defects). Also,
where one would not dream of manufacturing a part with subtractive techniques without a dimensional tolerance scheme, it is still not clear exactly how to apply tolerance principles to AM parts [1]. AM does not currently have the benefit of the over one hundred years of research into the production of components that is the hallmark of precision subtractive techniques
Chitosan-coated microvesicles: Effect of polysaccharide-phospholipid affinity on decafluorobutane dissolution
PICHETH G, PIRICH C, [...], Carbohydrate Polymers, [PicoImage]
The stability of perfluorinated microvesicles is mainly determined by the presence of interfacial materials and their ability to hinder the gas component diffusibility into the bloodstream. The goal of this study is to increase the persistence of the gaseous-core by introducing chitosan-coated 1,2-distearoyl-sn-glycero-3-phosphocholine (DSPC) microvesicles, reducing gas diffusion from microvesicles, and increasing for a long time ultrasonic signals. Our hypothesis was based on the irreversible adhesion of chitosan towards DSPC head groups observed in thin-films models. This affinity enhanced the stabilization of gaseous-core microvesicles, in which the polysaccharide effectively reduced the phospholipid phase transition enthalpy from 383 ± 5.5 J mg−1 for plain to 150 ± 9.7 J mg−1 for chitosan-coated microvesicles, providing a more stable structure that diminished the gaseous component lost and provided the persistence of intense 19F-NMR signals after 48 h, twice as long compared to plain samples. As a result, stronger and long-lasting ultrasonic signals were produced by the more stable chitosan-containing microvesicles, thus, presenting great potential to increase the diagnostic and therapeutic applications of perfluorocarbon carries.
Microfluidic and terahertz technologies for integrated spectroscopic systems
COLLIER C M, PhD thesis, Univ British Columbia, [MountainsMap]
The terahertz (THz) spectrum, being approximately 0.1-10 THz, is the region of the electromagnetic spectrum that lies beyond the reach of electronic and optical devices. Because of this unique spectral region, THz radiation has found its place in many contemporary applications. In particular, THz radiation has been used in biochemical analyses, via THz
spectroscopy. Terahertz spectroscopy is sensitive to vibrational and rotational modes of organic species, and this functionality can be enhanced by integrating THz spectroscopy within lab-on-a-chip platforms. Such platforms can enable high-sensitivity and rapid interrogation of biochemical species via THz spectroscopy. However, the integration of THz spectroscopy in lab-on-a-chip platforms has not yet been achieved. [...]
Application of a colorimetric technique in quality control for printed pediatric orodispersible drug delivery systems containing propranolol hydrochloride
VAKILI H, NYMAN J O, [...], Int J Pharmaceutics, 511(1), [MountainsMap]
The feasibility of a colorimetric technique was investigated in CIELAB color space as an analytical quality control method for content uniformity of printed orodispersible pediatric delivery systems. Inkjet printing was utilized to fabricate orodispersibe film formulations containing propranolol hydrochloride in a colored ink base using three different edible substrates. A thin sweetener coating layer of saccharin was successfully included in the final dosage forms for palatability purposes using a casting knife. Optical microscopy, scanning electron microscopy and scanning white light interferometry analyses were conducted to study the effect of printing on the surface morphology and topography of the substrates. Differential scanning calorimetry and attenuated total reflectance infrared spectroscopy were used to study the solid state properties and possible interactions between the drug and the excipients. The inkjet printing technique deposited precise and uniform escalating doses (0.08 3.16 mg) of the active pharmaceutical ingredient onto the substrates (R2 0.9934). A disintegration test with clear end-point detection confirmed that all the substrates meet the requirements of the Ph. Eur. to disintegrate within 180 s. The colorimetric technique proved to be a reliable method to distinguish the small color differences between formulations containing an escalating dose of propranolol hydrochloride.
Seeds, browse, and tooth wear: a sheep perspective
RAMDARSHAN A, BLONDEL C, [...], Ecology and Evolution, [LeicaMap]
While grazing as a selective factor towards hypsodont dentition on mammals has gained a lot of attention, the importance of fruits and seeds as fallback resources for many browsing ungulates has caught much less attention. Controlled-food experiments, by reducing the dietary range, allow for a direct quantification of the effect of each type of items separately on enamel abrasion. We present the results of a dental microwear texture analysis on 40 ewes clustered into four different controlled diets: clover alone, and then three diets composed of clover together with either barley, corn, or chestnuts. Among the seed-eating groups, only the barley one shows higher complexity than the seed-free group. Canonical discriminant analysis is successful at correctly classifying the majority of clover- and seed-fed ewes. Although this study focuses on diets which all fall within a single dietary category (browse), the groups show variations in dental microwear textures in relation with the presence and the type of seeds. More than a matter of seed size and hardness, a high amount of kernels ingested per day is found to be correlated with high complexity on enamel molar facets. This highlights the high variability of the physical properties of the foods falling under the browsing umbrella.
Disentangling Epitaxial Growth Mechanisms of Solution Derived Functional Oxide Thin Films
QUERALTO A, DE LA MATA M, [...], Adv Mat Interfaces, 3(18), [MountainsMap]
This study investigates the mechanisms of epitaxial development and functional properties of oxide thin films (Ce0.9Zr0.1O2−y, LaNiO3, and Ba0.8Sr0.2TiO3) grown on single crystal substrates (Y2O3:ZrO2, LaAlO3, and SrTiO3) by the chemical solution deposition approach. Rapid thermal annealing furnaces are very powerful tools in this study providing valuable information of the early stages of nucleation, the kinetics of epitaxial film growth, and the coarsening of nanocrystalline phases. Advanced transmission electron microscopies, X-ray diffraction, and atomic force microscopy are employed to investigate the film microstructure and morphology, microstrain relaxation, and epitaxial crystallization. This study demonstrates that the isothermal evolution toward epitaxial film growth follows a self-limited process driven by atomic diffusion, and surface and interface energy minimization. All investigated oxides experience a transformation from the polycrystalline to the epitaxial phase. This study unequivocally evidences that the film thickness highly influences the epitaxial crystallization rate due to the competition between heterogeneous and homogeneous nucleation barriers and the fast coarsening of polycrystalline grains as compared to epitaxial growth. The investigated films possess good functional properties, and this study successfully confirms an improvement at long annealing times that can be correlated with grain boundary healing processes. Thick epitaxial films can be crystallized by growing sequential individual epitaxial layers.
Stimuli-responsive poly(N-vinylcaprolactam-co-2-methoxyethyl acrylate) core–shell microgels: facile synthesis, modulation of surface properties and controlled internalisation into cells
MELLE A, BALACEANU A, [...], J Mater Chem , [PicoImage]
Herein we report the synthesis of biocompatible stimuli-responsive core–shell microgels consisting of a poly(N-vinylcaprolactam) (PVCL) core and a poly(2-methoxyethyl acrylate) (PMEA) corona via one-step surfactant-free precipitation copolymerization. The copolymerization process was investigated by reaction calorimetry, microgel growth was monitored by in situ dynamic light scattering and the chemical structure of core–shell microgels was characterized by Raman spectroscopy. It was possible to incorporate up to 32 mol% MEA into the PVCL/MEA microgels without loss of colloidal stability and broadening of the size distribution. The core–shell morphology of microgels was confirmed by transverse magnetization relaxation 1H-NMR, dynamic light scattering (DLS), atomic force microscopy (AFM) and viscosimetry. By means of the NMR data, calorimetry and viscosity measurements it could be shown that MEA is mainly located in the microgel shell. This leads to hindered temperature-induced swelling and collapsing of the PVCL-core, as demonstrated by DLS measurements, due to the fact that the PMEA-shell exhibits a very low LCST around 5 °C. These results could also be confirmed by AFM: an increasing MEA-content leads to the formation of dense and compact core–shell microgels and results in a loss of their softness and deformability. Due to the presence of the PMEA-shell these microgels can be endocytosed much faster by HeLa cells maintaining their viability and can be suitable candidates for the design of drug carriers or imaging/diagnostic systems.
Micromorphology and fractal analysis of nickel–carbon composite thin films
TALU S, LUNA C, [...], J Mat Sci Materials in Electronics, [MountainsMap]
In this study nickel–carbon (Ni–C) nanocomposite thin films composed of Ni nanoparticles with different average sizes embedded in amorphous hydrogenated carbon, were prepared through the combination of radio frequency sputtering and plasma enhanced chemical vapor deposition techniques. Such samples were used as experimental models to study the three dimensional surface morphology properties in thin films by atomic force microscopy imaging and fractal analysis over square areas of 1 μm × 1 μm. The deposition time was varied at 7, 10 and 13 min, respectively, to study changes in the properties of the obtained films. The studied samples exhibited fractal properties characterized by fractal dimensions dependent on the deposition time with values between 2.43 ± 0.01 and 2.71 ± 0.01.
[PDF] Effect of Sodium Fluoride on the Stability of Dental Alloys in Artificial Saliva
COVACIU ROMONTI D, MILOSEV I, DEMETRESCU I, [Talymap]
Dental alloys as CoCrMo, SS 316L stainless steel and NiTi were electrochemically investigated in artificial Fusayama saliva, unmodified and modified with two different concentrations of natrium fluoride. Electrochemical tests include measurements of open circuit, measurements of linear polarization, potentiodinamic polarization curves and electrochemical impedance spectra. The best electrochemical behavior with a good corrosion resistance was found for the CoCrMo alloy, followed by stainless steel alloy. NiTi alloy was the most affected by the addition of fluoride ad the corrosion rate decreased dramatically. Based on our experimental data we can conclude that the addition of sodium fluoride increases the corrosion rate
Process and composition dependence of optical properties of zirconium, hafnium and tantalum borides for solar receiver applications
SANI E, MERCATELLI L, [...], Solar energy materials and solar cells, 155, [Talymap]
Ultra-high temperature boride ceramics have proved to show promising properties for novel solar receivers. The present work shows a further step towards their actual application, investigating how sintering technique and starting powders composition affect the properties of final materials. Thus we report on the comparative characterization of ZrB2, HfB2 and TaB2 produced by high pressure and pressureless techniques and with different amounts of MoSi2 sintering aid. We investigate microstructural, mechanical and optical properties, in the perspective to assess the material potential for novel solar absorbers operating at higher temperatures than those currently available. Moreover, a systematic study has been carried out on ZrB2, producing with fixed high pressure sintering technique, a series of samples with MoSi2 compositions in the range 5–50 vol%. We show that the content of silicide and silicide-related secondary phases in the final pellets affects either the mechanical performance and the optical behavior. Thus, as far as the optical properties are concerned, the MoSi2 amount should be the lowest as possible to ensure a proper material consolidation whilst enhancing the absorbance/spectral selectivity.
Microstructural and abrasion wear characteristics of laser-clad tool steel coatings
TUOMINEN J, NÄKKI J, HYVÄRINEN L, VUORISTP P, Surface Engineering, 32, [MountainsMap]
Several different tool steel grades were deposited on mild steel by the laser-cladding process with coaxial powder feeding. With bidirectional scanning pattern, most of the grades were deposited crack-free with hardness up to 1000 HV without additional preheating. In a 3-body abrasion wear study, the laser clad Ralloy® WR6 with significant portion of retained austenite exhibited superior abrasive wear resistance compared with the predominantly martensitic tool steel coatings (M2, M4, H13, HS-23, HS-30) and the reference material, Raex® Ar500 wear resistant steel. The abrasion wear resistance of austenitic–martensitic WR6 tool steel was further enhanced by the external addition of 20% volume percentage of relatively large (45–106 µm) vanadium carbides. In single point scratch tests, predominantly martensitic tool steels outperformed austenitic–martensitic tool steels and wear resistant steel. The differences in wear performances were explained by different wear mechanisms and types of contact between the abrasive and the surface.
[PDF] Nanostructured Organic/Inorganic Semicondutor
Photovoltaics: Investigation on Morphology and Optoelectronics Performance
WANNINAYAKE A, PhD thesis, Univ Wisconsin-Milwaukee, [PicoImage]
Organic solar cell is a promising technology because of the versatility of organic materials in terms of tunability of their electrical and optical properties. In addition, their relative
insensitivity to film imperfections potentially allows for very low-cost high-throughput roll-toroll processing. However, the power conversion efficiency of organic solar cell is still limited
and needs to be improved in order to be competitive with grid parity. This work is focused on the design and characterization of a new organic/inorganic hybrid device to enhance the efficiency
factors of bilayer organic solar cells such as: light absorption, exciton diffusion, exciton dissociation, charge transportation and charge collection at the electrodes. In a hybrid solar cell
operation, external quantum efficiency is determined by these five factors. The external quantum efficiency has linear relationship to the power conversation efficiency via short circuit current density.
Experimental investigation into fabrication of microfeatures on titanium by electrochemical micromachining
S S ANASANE, B BHATTACHARYYA, Adv Manuf, [Talymap]
Titanium machining is one of the challenging tasks to modern machining processes. Especially fabricating microfeatures on titanium appear as a potential research interest. Electrochemical micromachining (EMM) is an effective process to generate microfeatures by anodic dissolution. Machining of titanium by anodic dissolution is different than other metals because of its tendency to form passive oxide layer. The phenomenon of progression of microfeature by conversion of passive oxide layer into transpassive has been investigated with the help of maskless EMM technique. Suitable range of machining voltage has been established to attain the controlled anodic dissolution of titanium by converting passive oxide film of titanium into transpassive with nonaqueous electrolyte. The experimental outcomes revealed that the micromachining of titanium with controlled anodic dissolution could be possible even at lower machining voltage in the range of 6–8 V. This work successfully explored the possibility of generation of microfeatures on commercially pure titanium by anodic dissolution process in microscopic domain by demonstrating successful fabrication of various microfeatures, such as microholes and microcantilevers.
[PDF] Processing, Mechanical and Optical Properties of Additive-Free ZrC Ceramics Prepared by Spark Plasma Sintering
C MUSA, R LICHERI, [...], Materials, [Talymap]
In the present study, nearly fully dense monolithic ZrC samples are produced and broadly characterized from microstructural, mechanical and optical points of view. Specifically, 98% dense products are obtained by Spark Plasma Sintering (SPS) after 20 min dwell time at 1850°C starting from
powders preliminarily prepared by Self-propagating High-temperature Synthesis (SHS) followed by 20 min ball milling. A prolonged mechanical treatment up to 2 h of SHS powders does not lead to appreciable benefits. Vickers hardness of the resulting samples (17.5 +/- 0.4 GPa) is reasonably good for monolithic ceramics, but the mechanical strength (about 250 MPa up to 1000°C) could be further
improved by suitable optimization of the starting powder characteristics. The very smoothly polished ZrC specimen subjected to optical measurements displays high absorption in the visible-near infrared region and low thermal emittance at longer wavelengths. Moreover, the sample exhibits goodspectral selectivity (2.1–2.4) in the 1000–1400 K temperature range. These preliminary results suggest that ZrC ceramics produced through the two-step SHS/SPS processing route can be considered as attractive reference materials for the development of innovative solar energy absorbers.
Side Effect of Good's Buffers on Optical Properties of Gold Nanoparticle Solutions
C ENGELBREKT, M WAGNER, [...], ChemElectroChem, [PicoImage]
In search of fluorescent nanoclusters (NCs) for bioimaging, several methods of synthesis have been attempted. Particularly, formation of gold NCs (AuNCs) during synthesis of gold nanoparticles (AuNPs) using Good's buffers has been reported based on the optical properties of the reaction mixtures. Here we chose Good's buffers 2-(N-morpholino)ethanesulfonic acid (MES), 3-(N-morpholino)propanesulfonic acid (MOPS) and 4-(N-morpholino)butanesulfonic acid (MOBS) as [AuCl4]−-reducing agents. Resulting AuNP solutions were subjected to electrochemical investigations along with UV/Vis and fluorescence spectroscopy. Distinct absorption features at approximately 290 and 360 nm and fluorescence emission in the 408–484 nm range in filtered AuNP-free solutions were observed. Electrochemical oxidation of these buffers generates similar optical properties, suggesting that the degradation products of the buffers contribute to the optical properties of AuNP solutions. This work indicates that a deeper evaluation of fluorescence signals based on metal NPs or NCs is needed.
Plasmonic Effect of Au Nanoparticles in Enhancing Power Conversion Efficiency of ZnO Buffer Layer Assembled Organic Solar Cells
A P WABBIBAYAKE, B C BENJAMIN, N ABU-ZAHRA, J Sustainable Energy Engineering, [PicoImage]
Gold (Au) nanoparticles are incorporated into the P3HT/PCBM active layer of organic solar cells in order to enhance their power conversion efficiency (PCE). In addition, a zinc oxide (ZnO) buffer layer was assembled on top of the P3HT/PCBM/Au-NPs active layer in order to increase the charge mobility across the cells. The incorporation of Au-NPs in the active layer and the addition of a ZnO buffer layer increased the power conversion efficiency by approximately 60%, compared to a reference cell without Au-NPs and a buffer layer. The short circuit current (J sc) of the cells containing 0.5 mg of Au-NPs and a ZnO buffer layer was measured at 7.381 mA/cm2 compared to 5.225 mA/cm2 in the reference cells; meanwhile, the external quantum efficiency (EQE) increased from 61.25% to 68.23%, showing an enhancement of 11.4%. Furthermore, Au-NPs improved the charge collection at the anode, which resulted in a higher short circuit current and fill factor. The strong near field around Au-NPs due to a localized surface plasmonic resonance (LSPR) effect enhanced the light absorption in the active layer, and hence the overall electrical performance of the cells.
New perspective on morphological features of the zinc oxide thin films as a gas sensor
R ALIPOUR, M T HOSSEINNEJAD, [...], J Alloys Compounds, [MountainsMap]
In this experimental research, the effects of the thermal oxidation time on the morphological characteristics of ZnO thin films and the impact of these features on the gas response of samples were investigated. For this purpose, the thin layers of zinc were deposited on glass substrates by DC magnetron sputtering method. To oxidation the samples and produce zinc oxide thin films the thermal oxidation method was used. The X-ray diffraction analysis is used to specify the deposited thin layers. The results of the Scherrer formula showed that the grain size of the grown ZnO thin films was increased with increasing oxidation time. The efficiency of gas sensor of deposited samples at different thermal oxidation times was investigated. The results show that the increase in the oxidation time (which leads to the increase in ZnO grain size) leads to the reduction of gas response α. Also, To study the effects of the morphological characteristics of synthesized ZnO thin films on the gas response, the atomic force microscopy (AFM) analysis, the Mountains Map Premium 7.3 (64-bit version) software and the Gwyddion software were used. By using the results of motifs analysis and the statistical parameters of samples, it could be concluded that the gas response of the ZnO thin films decreased with increasing the surface roughness, density and intensity of peaks on the surfaces of the samples. Also, the results show that the gas response α increased with increasing temperature and this increase of gas response is more intense at higher temperatures. The results of this paper provide new perspectives for the researcher in this field.
The effect of pressure on morphological features and quality of synthesized graphene
R ALIPOUR, M R RIAZIFAR, T AFSARI, Research Chemical Intermediates,
Graphene was grown on copper foils using a low pressure chemical vapor deposition technique. In this experiment the pressure varied from 0.1 to 4 Torr, the time was maintained at 150 s, the temperature was kept at 1000 °C, and the flow rate of hydrogen and methane was 10 and 30 sccm, respectively. To characterize the graphene layer formed on the copper foil, Raman spectra and SEM were analyzed. From the Raman spectra of samples, the ratio of I D/I G increases and the grain size of synthesized graphene samples decreases with rising pressure of the reaction chamber. The effect of low pressure on the density is clearly obvious since the ratio of I D/I G is less than 0.2. A lower value showed fewer defects. For the first time, MountainsMap Premium and Gwyddion software were used to investigate the morphological characteristics and quality of graphene samples. The results suggest that the density of graphene particles on the surface rises with rising pressure. It can be concluded that the density, uniformity, and the grain size of the synthesized graphene are controlled by changing the pressure of the reaction chamber.
Three dimensional topographic studies on worn surfaces of coated cemented carbide tools with different workpiece materials
R BEJJANI, M COLLIN, CIRP J Manuf Sci Tech, [MountainsMap]
Different worn surfaces were observed when machining different types of workpiece materials using similarly coated cemented carbide inserts. This study focuses on the flank wear within the coating. A clear difference in wear patterns were observed on worn surfaces depending on the workpiece material used. The worn surface was characterized by 3D surface topography using white light interferometry. Additionally, TEM studies were used to increase the understanding between the relations of the workpiece materials to the resulting worn surfaces. The added information from the worn surfaces and TEM investigations can help in better understanding the wear mechanism when machining different workpiece materials.
Conductive microfluidic interconnects to enable scalable 3D manufacturing of wearable electronics
J FLOWERS, C LIU, [...], IEEE Electronic Components Tech Conf, [MountainsMap]
This paper investigates the geometry and surface
finish of channels machined into polydimethylsiloxane using a continuous wave CO2 laser. In order to investigate the various mechanisms, that could affect the channel geometry, both the laser power and trace speed were varied in conjunction with the use of a fixed focal size to allow comparison between
configurations. It was discovered that as the power level increases, repeatability decreases while dimensional variability of the channel along its length and multiple iterations increases. It was found that the power output of the laser has a greater effect on the dimensions of the channels than the total
energy input into the material. Varying configurations were used when creating these channels resulting in a strong correlation between both power and speed with regard to depth. However, at higher energy levels this relationship
appears to break down and the depth of the cut reduces when compared to similar laser configurations at a lower power level.
Synthesis and investigation of silicon carbide nanowires by HFCVD method
S H MORTAZAVI, M GHORANNEVISS, [...], B Mat Sci, [MountainsMap]
Silicon carbide (SiC) nanowire was fabricated by hot filament chemical vapour deposition (HFCVD) mechanism in the temperature range of 600–800°C, under vacuum in the atmospheres of hexamethyldisiloxane/ alcohol (HMDSO/C2H5OH) vapour and argon gas mixture without using of a metal catalyst. In this work, temperature dependence of the SiC properties was discussed. Morphology and structural properties of SiC nanowire grown on the glass substrate were characterized by field emission scanning electron microscopy (FESEM), X-ray diffraction (XRD), energy diffraction spectrometer (EDS) and four-point probe (4PP). Also, to investigate on morphological features of samples, the Mountains Map Premium (64-bit version) software is used. In this context, analysis of the motifs, depth histograms, statistical parameters, texture direction, fractal and the peak count histograms of the nanostructure surface of samples were carried out. According to analysis, SiC films had a good crystal quality without defects and a low residual stress. We found that by rising substrate temperature, silicon and oxygen doping amount were raised. Results also show that electrical resistivity and the surface roughness raised by rising substrate temperature. High density SiC nanowire was grown on the free catalyst glass substrate and the alignment of SiC nanowires was decreased.
Design and Fabrication of Nanofluidic Systems for Biomolecule Characterizations
O A HIBBERT, Master's Thesis, [PicoImage]
Nanofluidic channel systems were designed and fabricated by combining MEMS microfabrication with AFM nanolithography. In the fabrication process flow, photolithography was first utilized to pattern microfluidic channels and reservoirs on a 4'' Pyrex substrate. Subsequently, atomic force microscopy (AFM) based nanolithography was used to mechanically
fabricate nanochannels to connect the microreservoirs which formed the inlet and outlet of the nanofluidic system. A Tap190 Diamond-Like Carbon (DLC) AFM tip with a force constant of 48 N/m and a radius of less than 15 nm was used as the nanolithography tool. The resultant nanochannel ranges from 20 to 80 µm in length and 10 to 100 nm in depth. After AFM, the Pyrex micro- and nanochannels were sealed off by a matching silicon capping piece using anodic bonding. Fluidic connectors are then attached to the inlet and outlet openings to complete the fabrication process. The relationship between the nanolithography parameters of the AFM and the resultant nanochannel dimensions was investigated in detail. A mostly linear trend was obtained between the AFM tip force and the nanochannel depth for a tip speed of 1 µm/s. This result was consistent with established nanotribological models and similar studies on silicon substrates. The
relationship between the number of repeated scratches and the nanochannel depth was also investigated. The results indicated that the nanochannel depth increased with the number of scratches. A depth of about 20 nm was typically achieved with 25 scratches at a tip force of 25 µN. The width of the nanochannel also increased with the number of scratches. A typical nanochannel width of 120 nm was achieved for 25 scratches at 10 µN.
[PDF] A Study on the Effect of Abrasive Filament Tool on Performance of Sliding Guideways for Machine Tools
N RAYMOND, M SOSHI, Procedia CIRP, [MountainsMap]
Sliding guideways for machine tools require smooth, consistent surface texture for optimal performance. An excessively smooth surface causes adhesion between the moving components, while a rough surface accelerates wear. Conventional guideway fabrication uses large, expensive grinding machines. To reduce manufacturing costs while maintaining functional performance, cubic boron nitride (CBN) milling followed by abrasive surface polishing has been proposed. This study investigates the use of an abrasive filament tool to correlate the effect of polishing with lubricated static/dynamic friction coefficients. The results are compared with the sliding performance of milled and ground hardened grey cast iron samples. It was found that polishing had the largest effect on surfaces that were previously milled at higher feed rates and, if realized by industry, could increase productivity.
Data acquisition variability using profilometry to produce accurate mean total volumetric wear and mean maximum wear depth measurements for the OHSU oral wear simulator
J P FLEMING, E REILLY, [...], Dental Materials, [Talymap]
To identify the minimum data acquisition variables in the x- and y-planes required when using three-dimensional (3D) profilometry to produce accurate mean total volumetric wear and mean maximum wear depth measurements for a range of wear facets produced by an oral wear simulator. The Oregon Health Science University (OHSU) oral wear simulator was employed to wear an experimental resin-based composite formulation from 25,000 to 400,000 wear cycles. Mean total volumetric wear and mean maximum wear depth were determined using a contact profilometry at a measurement speed of 1 mm/s. An area (8 mm length and 4 mm width) was profiled on each wear facet comprising 8001 horizontal traces (y-axis at 1 μm intervals) with 4001 measurement points (x-axis at 1 μm intervals) resulting in 32,012,001 measurement points with a z-axis resolution of 40 nm. The minimum x- and y-axis spacing data acquisition requirement were assessed using the TalyMap software by reducing the number of measurement points in the original scanned wear facets and normalized data were converted to percentage values. Minimum x- and y-axis spacing to achieve an accuracy of 99, 95 and 90% of the mean total volumetric wear value for the wear facets produced (25,000–400,000 wear cycles) were 20 μm × 20 μm, 100 μm × 100 μm and 200 μm × 200 μm, respectively but for maximum wear depth data normalized with respect to the ‘true value or gold standard’ the x- and y-axis spacing requirement varied with the size of the wear facet. The study emphasizes the difficulty in employing mean maximum wear depth measurements when assessing the in vitro wear facets produced by an OHSU oral wear simulator and accurate quantification of the mean total volumetric wear of a wear facet is a prerequisite to informing the profession about dental restorative wear performance.
A non-destructive internal nuclear forensic investigation at Argonne: discovery of a Pu planchet from 1948
J A SAVINA, J L STEEB, [...], J Radioanalytical Nuclear Chem, [PicoImage]
A plutonium alpha standard dating from 1948 was discovered at Argonne National Laboratory and characterized using a number of non-destructive analytical techniques. The principle radioactive isotope was found to be 239Pu and unique ring structures were found across the surface of the deposition area. Due to chronological constraints on possible sources and its high isotopic purity, the plutonium in the sample was likely produced by the Oak Ridge National Lab X-10 Reactor. It is proposed that the rings are resultant through a combination of polishing and electrodeposition, though the hypothesis fails to address a few key features of the ring structures.
Influence of structure isotropy of machined surface on the wear process
M MATUSZEWSKI, T MIKOLAJCZYK, [...], Int J Adv Manuf Tech, [Talymap]
In this paper, the influence of the configuration of the geometric structure of the machined surface on the course of the wear process of frictional pairs is discussed. Arrangement of traces of machining determined the level of surface structure isotropy. The characteristics of surface layers are discussed, with particular emphasis on the surface structure isotropy. The results of experimental investigations carried out on the specially designed and made setup are presented. As the measures of the wear process, the following quantities were determined: the mass decrement of samples and changes of the surface roughness parameters, root mean square (RMS) of profile R q and reduced peak height of profile R pk . The results of experimental investigations were registered for structures with different levels of isotropy and, thus, traces of machining. The investigations confirm the influence of the tested factors on the intensity of the wear process.
Nanoscale Surface Characterization of Ceramic/Ceramic Coated Metallic Biomaterials Using Chromatic Length Aberration Technique
J LEENA, V ARUMUGHAM, [...], MAPAN, [Talymap]
With the chromatic length aberration (CLA) technique, imaging of surfaces with complex three dimensional geometry is possible. Analysis of sample sizes in micro or nanometer scale is an added advantage available with CLA system. This article describes the methodology adopted for establishing the CLA technique for characterizing selected ceramic/ceramic coated substrates used in cardiovascular and orthopedic applications. The measurement of surface finish and coating thickness were validated against benchmarked technologies based on atomic force microscopy (AFM), stylus profilometry and standard ball cratering methods. Results of measurements were statistically analyzed by Student t test and reported the two tail p values to compare the results from different measurements techniques.
[PDF] Physics-based Surface Roughness Prediction in Wire-Electric Discharge Machining Processes
Y LI, A ANNAVAJHULA, Proc 15th Indus Syst Eng Research Conf, [MountainsMap]
Wire-Electric Discharge Machining (Wire- EDM) is a spark erosion process used to produce metal parts with fine
surface finish. Each electric discharge between the wire electrode and workpiece creates a crater on the workpiece material in a very short amount of time, and collectively on a macro scale the craters remove material as the wire is moving along a programmed tool path. This research intends to simulate the performance of Wire-EDM machining
process in the form of surface roughness and feed rate as they are key indicators to describe the surface finish on a machined workpiece and machining efficiency, respectively. In the developed simulation model, the work piece is discretized into an array of three-dimensional grid points, each of which is tested for a potential discharge with the
wire based on physics laws of Wire-EDM process. The simulation result was compared with the result of experiment conducted on a Sodick VZ 300L EDM machine with low carbon steel used as the work piece. The
comparison between simulated data and experimental data suggests that the method is able to serve to predict surface roughness and feed rate of Wire-EDM machines.
Surface Polishing of Hardened Grey Cast Iron with a Compliant Abrasive Filament Tool
N RAYMOND, M SOSHI, Procedia CIRP, [MountainsMap]
Sliding guideways play a critical role in the accuracy and dynamic performance of machine tools. Discontinuous jerking motion occurs due to wringing if the guides are too smooth, but excessive wear results is the surface is too rough. The current fabrication approach uses large and expensive grinding machines that place logistical restrictions on production. A higher productivity milling process, using cubic boron nitride (CBN) tooling has been attempted, but this process does not achieve the necessary surface quality. Secondary finishing using a spindle mounted abrasive filament tool could be implemented as a post process to improve surface quality. This study determined the relationship between number of passes and Spk, Sk, and Svk areal functional parameters for three types of filament tools.
[PDF] Investigations into bond strength between EDCC/Masonry
Y YAN, Master Thesis, U British Columbia, Vancouver, [MountainsMap]
In order to apply Sprayable Eco-Friendly Ductile Cementitious Composites (EDCC) as a thin overlay material for masonry building upgrade, this study aims at understanding one of the key issues of repair: bond strength between old structure and the new repair overlay. Several influencing factors on bond strength were investigated, including repair thickness, fiber addition, substrate properties, curing age and environment. Bond strength was measured by tensile pull-off and friction-transfer tests. At the conclusion of the research, EDCC was able to achieve satisfactory bond strength provided sufficient penetrability into the substrate, even under field conditions and without curing. Fibers added into EDCC impact bond strength negatively, if they are oriented parallel to the interface as a result of manual casting or if there is a low fractal dimension of the substrate surface. Further, 56 days can be used as the maturity age of bond strength with EDCC overlay. In future applications, penetrability of EDCC overlays can be ensured through sufficient amount of superplasticizer or energy of casting. For example, EDCC with 150mm slump was able to satisfy standard bond strength requirement of concrete in the field, at the age of 45 days. Penetrability of EDCC overlay is of vital importance, since EDCC with low workability (0 slump) can’t achieve requirement of structural repair even under standard curing. To mitigate the negative effect of fiber addition on bond strength, higher substrate roughness and 3D fiber orientation can be of help, through proper surface roughness preparation and the use of spray methods (e.g., shotcrete) instead of hand application. For further study, it is suggested that measures should be taken to obtain more pure bond strength values for simplification of analysis. Also surface roughness variation and long term properties of interface are worth investigation, once proper substrates are chosen for lab research.
[PDF] Effect of Mercapto and Methyl Groups on the Efficiency of Imidazole and Benzimidazole-based Inhibitors of Iron Corrosion
I MILOSEV, N KOVACEVIC, A KOKALJ, Acta Chim Slov, [Talymap]
We report on the combined experimental and computational study of imidazole- and benzimidazole-based corrosion inhibitors containing methyl and/or mercapto groups. Electrochemical measurements and long-term immersion tests were performed on iron in NaCl solution, whilst computational study explicitly addresses the molecular level details of the bonding on iron surface by means of density functional theory calculations (DFT). Experimental data were the basis for the determination of inhibition efficiency and mechanism. Methyl group combined with mercapto group has a beneficial
effect on corrosion inhibition at all inhibitor concentrations. The beneficial effect of mercapto group combined with benzene group is not so pronounced as when combined with methyl group. The latter is in stark contrast with the behaviour found previously on copper, where the effect of methyl group was detrimental and that of mercapto and benzene
beneficial. Explicit DFT calculations reveal that methyl-group has a small effect on the inhibitor–surface interaction. In contrast, the presence of mercapto group involves the strong S–surface bonding and consequently the adsorption of inhibitors with mercapto group is found to be more exothermic.
Modulation of Coordinate Bonds in Hydrogen-Bonded Trimesic Acid Molecular Networks on Highly Ordered Pyrolytic Graphite Surface
W LI, J JIN, [...], J Phys Chem C, [PicoImage]
The modulation effects of metal nitrites on the hydrogen-bonded supramolecular structure of trimesic acid on a graphite surface have been investigated at the liquid–solid interface by scanning tunneling microscopy (STM). The STM observations demonstrate that the self-assembled hydrogen-bonded molecular networks of trimesic acid (TMA) have been significantly transformed after the introduction of various metal nitrites. It is found that for the nitrite containing full orbital metals (AgNO3 and Zn(NO3)2), the pristine nitrite molecules are directly embedded into the pores within the TMA networks. In contrast, for the nitrite with vacant orbital metals (Cu(NO3)2, Mn(NO3)2 and Fe(NO3)3), the metal–organic coordination networks with various structures are formed due to the incorporations of the metal ions.
Canine and incisor microwear in pitheciids and Ateles reflects documented patterns of tooth use
L K DELEZENE, M F TEAFORD, P S UNGAR, Am J Phys Anthropol, [SensoMap]
Platyrrhine species differ in the extent to and the manner in which they use their incisors and canines during food ingestion. For example, Ateles uses its anterior teeth to process mechanically nondemanding soft fruits, while the sclerocarp-harvesting pitheciids rely extensively on these teeth to acquire and process more demanding foods. Pitheciids themselves vary in anterior tooth use, with the pitheciines (Cacajao, Chiropotes, and Pithecia) noted to use their robust canines in a variety of ways to predate seeds, while Callicebus, which rarely predates seeds, uses its incisors and exceptionally short canines to scrape tough mesocarp from fruits. To investigate the relationship between tooth use and dental wear, microwear textures were investigated for the anterior teeth of these five genera of platyrrhine primates. Using a white light confocal microscope, 12 microwear texture attributes that reflect feature size, anisotropy, density, and complexity were recorded from high-resolution epoxy casts of the incisors and canines of adult wild-collected Brazilian specimens of Ateles, Callicebus, Cacajao, Chiropotes, and Pithecia. Pitheciine canines tend to have deep microwear features and complex, anisotropic microwear textures, while Ateles anterior teeth tend to have very small features, low feature density, and less complex and anisotropic surfaces. Callicebus incisor and canine microwear is generally intermediate in size and complexity between those extremes. These findings align with expectations from reported field observations of tooth use and illustrate the potential for using microwear texture analysis to infer patterns of anterior tooth use in extinct primates.
An Early Instance of Upper Palaeolithic Personal Ornamentation from China: The Freshwater Shell Bead from Shuidonggou 2
Y WEI, F D'ERRICO, M VANHAEREN, F LI, X GAO, PLOS One, [LeicaMap]
We report the discovery and present a detailed analysis of a freshwater bivalve from Shuidonggou Locality 2, layer CL3. This layer is located c. 40 cm below layer CL2, which has yielded numerous ostrich eggshell beads. The shell is identified as the valve of a Corbicula fluminea. Data on the occurrence of this species in the Shuidonggou region during Marine Isotope Stage 3 and taphonomic analysis, conducted in the framework of this study, of a modern biocoenosis and thanatocoenosis suggest that the archeological specimen was collected at one of the numerous fossil or sub-fossil outcrops where valves of this species were available at the time of occupation of level CL3. Experimental grinding and microscopic analysis of modern shells of the same species indicate that the Shuidonggou shell was most probably ground on coarse sandstone to open a hole on its umbo, attach a thread, and use the valve as a personal ornament. Experimental engraving of freshwater shells and microscopic analysis identify an incision crossing the archaeological valve outer surface as possible deliberate engraving. Reappraisal of the site chronology in the light of available radiocarbon evidence suggests an age of at least 34–33 cal kyr BP for layer CL3. Such estimate makes the C. fluminea recovered from CL3 one of the earliest instances of personal ornamentation and the earliest example of a shell bead from China.
[PDF] Metrological changes in the surface morphology of cereal grains in the mixing process
J B KROLCZYK, Int Agrophysics, [MountainsMap]
The paper presents a new idea of approach to the analysis of surface morphology of cereal grains. In this paper, the surfaces of maize were analyzed using an optical 3D measurement system to determine the surface morphology and parameters of surface topography. It was established how changes in the moisture influence on the surface characteristics. Comprehensive parametric analysis was conducted for maize grains with different moisture contents. The objective of this study was to comprehensively characterize the surface morphology of maize in contact area using standardized 3D roughness parameters as well as other characteristics such as structure direction and isotropy. This is the first study that has presented, elucidated, and discussed the relationships between some morphological parameters of cereal grains. This research contributes to better understanding of the
mixing process. The main findings are: the values of roughness parameters kurtosis and skewness are characterized by higher values for maize grains with lower moisture, compared with maize grains with higher moisture content; there is a close relationship between the maize grain moisture content and the surface roughness parameters of kurtosis and skewness; maize grains have an anisotropic structure.
[PDF] Multi-scale curvature tensor analysis of surfaces created by micro-EDM and functional correlations with discharge energy
T BARTKOWIAK, J HYDE, C BROWN, 5th Int Conf on Surface Metrology, [MountainsMap]
The objective of this work is to demonstrate the use of multi-scale curvature tensor analysis to characterize surfaces of
stainless steel created by micro-electric discharge machining (μEDM) process and to study the relation between the energy of the discharge and the resulting surface curvature. In particular, the strength of the correlations between curvature characterizations (i.e., principal, Gaussian or mean curvature) and discharge energies is sought. The role of
scale in the measurement and characterization of the surfaces is also studied. The subject of the study were samples created by micro-EDM techniques using energies from 18nJ to 16 500nJ and measured by confocal microscope. The curvature tensor T is calculated using normal based method and the multi-scale effect is achieved by changing the size
of the sampling interval for normal estimation and tiling. Normals are estimated from regular meshes by applying covariance matrix method. Strong correlations (R2>0.9) are observed between calculated principal maximal and minimal as well as mean and Gaussian curvatures and discharge energies. The method incorporated in the paper
allows detailed analysis of the nature of surface topographies and to potentially detect that different formation processes governed the creation of surfaces created by higher energies.
Experimental investigation into the effect of chatter on surface micro-topography of gears in grinding
L YAO, W XIUFENG, L JING, Z WEI, J Mech Eng Sci, [MountainsMap]
Chatter affects the surface topography and functional performance of work pieces significantly. The surface topography of work pieces is multi-scale, and the characteristics of different levels of the surface topography are closely connected to the different functional performance of the work piece. The relationship between chatter vibration and surface micro-topography is complicated and not specified. By investigating and understanding this relationship clearly, the manufacturing process can be directed to be controlled more actively and accurately, which helps complete the product with expected surface topography and functional performance. This paper aims to reveal the effect of chatter on the surface micro-topography of gears in grinding. Grinding processes considering different machining states and surface topographies of gears under each process were analyzed comprehensively. The following findings were observed. First, chatter causes significant increase of the tooth flank surface roughness in low frequency and increase of the profile roughness, whereas in a different manner in the different gear flank directions. Second, the influence of chatter mainly concentrates on certain frequency bands of the surface topography, and the effect of chatter on the 3D surface topography is within a frequency range. Third, chatter vibration with its multi-frequency-band characteristics shows a multi-scale influence on the work piece surface topography. The possible mechanisms for the formation of these effects were also discussed.
Comparison of precision hard turning and grinding operations in terms of the topographic analysis of machined surfaces
W GRZESIK, K ZAK, Int J of Surface Sci and Eng, [MountainsMap]
This paper presents the comparison of precision hard cutting and abrasive processes in terms of the surface textures produced and their effects on enhancing functional properties. The main objective of such a comparison is to facilitate the decision whether to possibly replace grinding operations by hard turning with low feed rates. The experimental study performed includes hard turning operations with CBN cutting tools and grinding operations using CBN wheels. For this purpose, the stereometric features of turned and ground surfaces with the Sa roughness parameter of about 0.2 μm were compared. Apart from the set of 3D roughness parameters, the motif, fractal and frequency characteristics were analysed.
[PDF] The Use of Focus-Variation Microscopy for the Assessment of Active Surfaces of a New Generation of Coated Abrasive Tools
W KAPLONEK, K NADOLNY, G M KROLCZYK, Meas Sci Rev, [Talymap]
In this paper, the selected results of measurements and analysis of the active surfaces of a new generation of coated abrasive tools obtained by the use of focus-variation microscopy (FVM) are presented and discussed. The origin of this technique, as well as its general metrological characteristics is briefly described. Additionally, information regarding the focus variation microscope used in the
experiments – InfiniteFocus IF G4 produced by Alicona Imaging, is also given. The measurements were carried out on microfinishing
films (IMFF), abrasive portable belts with Cubitron II grains, and single-layer abrasive discs with Trizact grains. The obtained results
were processed and analyzed employing TalyMap 4.0 software in the form of maps and profiles, surface microtopographies, Abbott-Firestone curves, and calculated values of selected areal parameters. This allowed us to describe the active surfaces of the coated abrasive tools, as well as to assess the possibility of applying the FVM technique in such kinds of measurements.
Titanium carbide coating with enhanced tribological properties obtained by EDC using partially sintered titanium electrodes and graphite powder mixed dielectric
Z J XIE, Y J MAI, [...], Surfaces and coatings Tech, [Talymap]
The combination of partially sintered titanium tool electrode and graphite powder mixed dielectric is proposed to prepare titanium carbide coatings by electrical discharge coating technique with the major objective to improve their tribological properties. The phase composition and microstructure of the obtained coatings are characterized by x-ray diffraction, Raman spectrum, transmission electron microscopy and scanning electron microscopy. Their tribological performances are investigated by ball-on-disk tribometer and the corresponding mechanism of friction and wear are explored. Compared with the coatings obtained in dielectric without graphite powder, they show more uniform thickness and higher microhardness. They also show lower and steadier friction coefficient as well as better wear resistance especially in high load condition. These enhanced properties can be attributed to the suspended graphite powders in dielectric. They, as the additional carbon source, increase the transition of titanium tool electrode to titanium carbide and introduce amorphous carbon into the coatings. It is this amorphous carbon that continuously supplies the lubricant at the contact, helping to accommodate sliding motion and preventing the surfaces from mechanical wear and oxidation.
Preparation and atomic force microscopy of CTAB stabilized polythiophene nanoparticles thin film
P GRAAK, R DEVI, [...], AIP Conf Proc, [PicoImage]
Polythiophene nanoparticles were synthesized by iron catalyzed oxidative polymerization method. Polythiophene formation was detected by UV-Visible spectroscopy with λmax 375nm. Thin films of CTAB stabilized polythiophene nanoparticles was deposited on n-type silicon wafer by spin coating technique at 3000rpm in three cycles. Thickness of the thin films was computed as 300-350nm by ellipsometry. Atomic force micrscopyrevealws the particle size of polymeric nanoparticles in the range of 30nm to 100nm. Roughness of thinfilm was also analyzed from the atomic force microscopy data by Picoimage software. The observed RMS value lies in the range of 6 nm to 12 nm.
Effect of ultrasound combined with malic acid on the activity and conformation of mushroom (Agaricus bisporus) polyphenoloxidase
L ZHOU, W LIU, [...], Enzyme and Microbial Tech, [PicoImage]
Polyphenoloxidase (PPO) plays an important role in the browning of vegetables, fruits and edible fungi. The effects of ultrasound, malic acid, and their combination on the activity and conformation of mushroom (Agaricus bisporus) PPO were studied. The activity of PPO decreased gradually with the increasing of malic acid concentrations (5–60 mM). Neither medium concentrations (10, 20, 30 mM) malic acid nor individual ultrasound (25 kHz, 55.48 W/cm2) treatment could remarkably inactivate PPO. However, the inactivation during their combination was more significant than the sum of ultrasound inactivation and malic acid inactivation. The inactivation kinetics of PPO followed a first-order kinetics under the combination of ultrasound and malic acid. The conformation of combination treated PPO was changed, which was reflected in the decrease of α-helix, increase of β-sheet contents and disruption of the tertiary structure. Results of molecular microstructure showed that ultrasound broke large molecular groups of PPO into small ones. Moreover, combined treatment disrupted the microstructure of PPO and molecules were connected together.
Classical or inverted photovoltaic cells: On the importance of the morphology of the organic layers on their power conversion efficiency
F MARTINEZ, Z EL JOUAD, [...], Dyes and Pigments, [MountainsMap]
Novel organic thiophene derivatives, (E)-Bis-1,2-(5,5″-Dimethyl-(2,2′:3′,2″-terthiophene)vinylene (BSTV) and (E)-Bis-1,2-(5,5″-Dimethyl-(2,2′:3′,2″:3′,2‴-tetrathiophene)vinylene (BOTV), with different numbers of thiophene units, have been synthesized. They are introduced into organic photovoltaic cells as electron donor. The both organic photovoltaic cell configurations are probed: classical, i.e. with the ITO used as anode, and inverted, i.e. with ITO used as cathode. Whatever the cell configuration, the best results are obtained when a double cathode buffer layer Alq3/Ca is used. Actually, such double cathode buffer layer allows cumulating the advantages of its both constituents. The Alq3 blocks the excitons and protects the organic electron acceptor from cathode diffusion during its deposition, while the low work function of Ca induces a good band matching at the interface electron acceptor/cathode. On the other hand, it is shown that the organic layer surface morphology is decisive whatever the cell efficiency. While the BSTV layers are homogeneous those of BOTV are not. It follows that, in the case of classical organic photovoltaic cells, leakage currents limits the performances of the cells using BOTV, and better performances are obtained with BSTV. This difficulty is overcome in the case of inverted organic photovoltaic cells. This configuration allows limiting the effect of the inhomogeneities of the donor layer and better efficiencies are obtained with BOTV, which was expected due to its smaller band gap value.
Synthesis of Ag–Cu–Pd alloy by DC-magnetron sputtering: micromorphology analysis
N GHOBADI, S REZAEE, J of Mat Sci - Mat in Electronics, [MountainsMap]
The present paper aims at analyzing three dimensional (3-D) surface morphologies of Ag–Cu–Pd alloy thin films prepared by direct-current magnetron sputtering by using Argon gas and Ag–Cu–Pd target. These alloys, have been deposited on Si substrates, are investigated at three thicknesses (26, 34 and 40 nm). X-ray diffraction profile of the samples reveals that Cu, Ag and Pd NPs with FCC crystalline are formed in these films. The absorption spectra is applied to study surface Plasmon resonance peaks of Ag, Cu and Pd NPs (observed around 400 nm in visible spectral), which has been widened and shifted to higher wavelengths as the electrical resistivity increases. Applying the combination of atomic force microscopy, fractal analysis and statistical parameters over square area of 1 µm × 1 µm, the thin films were studied to determine the structure and the relationships among the (3-D) micro-textured surfaces. Fractal analysis can quantify basic parameters of (3-D) surface morphology like fractal dimension which is determined by the morphological envelopes method in the present study.
The technology of the earliest European cave paintings: El Castillo Cave, Spain
F D'ERRICO, L DAYET BOUILLOT, [...], J of Archaelogical Sci, [LeicaMap]
The red disks from El Castillo Cave are among the earliest known cave paintings. Here, we combine the morphometric and technological study of red disks from two areas located at the end of the cave with the microscopic, elemental, and mineralogical analysis of the pigment and compare the results obtained with observations derived from experimental replication. Ergonomic constraints imply that a number of disks were made by adults, and the differences in pigment texture and composition suggest that they correspond to an accumulation through time of panels made by different persons who shared neither the same technical know-how nor, very possibly, the same symbolic system.
Microsculpturing of Polymeric Surfaces by Compression Molding
G M TEDDE, D BELLISARIO, [...], Key Eng Mat, [Talymap]
Surface micropatterning of polymers is an important process in a large number of applications ranging from microelectronics, sensors design and material science, to tissue engineering and cell biology. In this study a simple and versatile method for manufacturing microscale polymer surface patterns has been developed. Micropatterned surfaces of acrylonitrile-butadiene-styrene (ABS) were engineered by compression molding. Two different micropatterned surfaces were fabricated using diverse molds. The first micropatterning was achieved on a brass mold by the intersection of instrumented microindentation traces. The second microsculptured surface was realized through a bronze sintered mold. The morphological aspects and the surface wettability after microsculpturing were investigated. The microsculptured ABS surface produced by the sintered mold shows a higher contact angle compared with those of flat ABS surfaces. From the experimental results, it was found that the intrinsic hydrophobicity of the material is enhanced simply through increasing surface roughness of the solid surface. The method presented is an economical process to fabricate hydrophobic microsculptured surfaces and it is suitable for many kinds of materials.
Tribological assessment of the interface injection mold/plastic part
N CRISAN, S DESCARTES, [...], Tribology Int, [MountainsMap]
One of the current challenges of the plastic injection process is linked to the importance given to product design that enables a strong differentiation. The key in developing optimal surface molds that can overcome the present disadvantages lies in the comprehension of the interactions that occur at the mold/injected piece interface. This paper focus on identification and evaluation of the contact conditions at that interface, taking into account the effect of the polishing, of the mold geometry and of the injected material. A critical characterization of the surface topography was performed to study the corrosion-mechanical attack and the mechanical-physico-chemical one on two molds.
Preparation and performance evaluation of poly (ether-imide) based anion exchange polymer membrane electrolyte for microbial fuel cell
M ELANGOVAN, S DHARMALINGAM, Int J of Hydrogen Energy, [Talymap]
The purpose of the present study is to synthesise quaternized poly (ether imide) (QPEI) membrane and its utilization as an anion exchange membrane (AEM) for microbial fuel cell (MFC) applications. The membrane's structural characterizations were confirmed by FT-IR and 1H NMR spectroscopy. The surface morphology was obtained by SEM and the surface roughness was determined using non-contact profilometer. The effect of surface roughness, water uptake on anti biofouling properties were studied. The influence of oxygen and specific substrate crossover on the anode and cathode potential were also discussed. The performance stability of a single chambered MFC (SCMFC) was compared with that of dual chambered MFC (DCMFC). The investigations on QPEI and the commercially available AEM (AMI-7001) revealed that the QPEI membrane showed good static and kinetic properties over the AEM-7001 membrane. An enhanced water uptake percentage and reduced membrane surface roughness were bound to improve the overall MFC performance.
Measuring shot peening media velocity by indent size comparison
E NORDIN, B ALFREDSSON, J of Mat Proc Tech, [SensoMap]
Shot peening is a manufacturing method that makes indentations on a components surface by impacting it with small steel balls (media). In a production environment the shot peening process is usually controlled by defining media size, coverage and Almen intensity. For simulating shot peening, the media velocity is needed and therefore it must be measured or correlated to the Almen intensity. This paper details a method to record indentations on a test plate and then compare them to single shot indentations with measured velocities. For small media sizes the results are in reasonable agreement with other published results but at larger sizes there is a larger spread in published results. It is therefore recommended that the media velocity is either measured directly or that the indents are analysed as presented in this paper.
Chitin whiskers reinforced carrageenan films as low adhesion cell substrates
S CORVAGLIA, S RODRIGUEZ, [...], Int J of Polymeric Mat and Polymeric Biomat, [PicoImage]
Carrageenan was used to prepare carrageenan films reinforced with chitin nanowhiskers. Atomic force microscopy was used to characterize the morphology and roughness of the films. Structural characterization was performed using X-ray diffraction and Fourier transform infrared spectroscopy. The mechanical properties were assessed by tensile tests. The prepared nanocomposites were used as cell substrate in order to explore their potential biological applications. HeLa cells were seeded on the samples in order to assess their biocompatibility. The preliminary results show good cell proliferation but low cell adhesion, demonstrating a potential application of this novel material as substrate for tumor cell culture.
On the topology of topography: a review
K C CLARCKE, B E ROMERO, Cartography and Geographic Inf Sci, [MountainsMap]
In the field of terrain analysis, a primary goal is to effectively identify topographic features for a better understanding of their associated processes. The relationships among features are, therefore, of particular importance. The concept of the surface network, involving and defined by such features as peaks, pits, various saddles, ridge lines, and the opposite course lines, can be a beneficial construct for describing and modeling any mathematical surface and, perhaps, topographic surfaces, as well. However, limitations of terrain data collection, storage, and computational processing have presented difficulties when attempting to make the jump from such logical constructs and their supporting mathematical theories to the development of tools and mapped products representing the measured topography of a landscape. Compared to feature extraction, less attention has been given to the topological relationships among topographic features. This article provides a chronological review of the development of surface network and critical point theory, the study of topography, and the progression of terrain analysis with particular consideration given to the application of surface network theory to represent the topology of topography. Any possible true computed surface network is concluded to be scale-dependent, fuzzy, and vague and its undisputed calculation elusive.
The influence of electron beam irradiation, plastic deformation, and re-irradiation on crystallinity degree, mechanical and sclerometric properties of GUR 1050 used for arthroplasty
A BARYLSKI, J MASZYBROCKA, [...], J of Applied Polumer Sci, [Talymap]
The article describes the influence of an electron beam irradiation (I), plastic deformation (D), and re-irradiation (R) on the properties of ultrahigh molecular weight polyethylene (GUR 1050). It was found that the modification through irradiation entailed a gradual increase in the degree of crystallinity (after irradiation–I). After plastic deformation and re-irradiation (IDR) the degree of crystallinity decreases which had a direct influence on the mechanical properties. The polymer irradiation only (technique I) resulted in an increase in the maximum stress as compared with the material in the initial state. The application of deformation and re-irradiation (technique IDR) allowed increasing the deformation resistance by more than 40%. Moreover, the irradiation with an electron beam resulted in the increase in hardness (H) and Young's modulus (E) proportionally to the applied irradiation dose and in the reduction of total indentation work (Wtot) and its components. After deformation and re-irradiation the polyethylene hardness went down. The application of technique (I) caused an improvement to the material abrasion resistance (reduction of parameter PD–working scratch depth) with the increasing irradiation dose. The introduction of deformation and re-irradiation did not have a material impact on parameter (PD) increasing at the same time elastic properties of UHMWPE (increase in parameter NPS–elastic recovery). Modification IDR has changed the wear mechanism (β) toward ploughing and has increased the abrasion-resistance index (Wβ) and also significantly reduced the coefficient of friction (μ) of GUR 1050.
Anaerobic Biodegradation of Alternative Fuels and Associated Biocorrosion of Carbon Steel in Marine Environments
R LIANG, D F AKTAS, [...], Environ Sci Technol, [MountainsMap]
Fuels that biodegrade too easily can exacerbate through-wall pitting corrosion of pipelines and tanks and result in unintentional environmental releases. We tested the biological stability of two emerging naval biofuels (camelina-JP5 and Fischer–Tropsch-F76) and their potential to exacerbate carbon steel corrosion in seawater incubations with and without a hydrocarbon-degrading sulfate-reducing bacterium. The inclusion of sediment or the positive control bacterium in the incubations stimulated a similar pattern of sulfate reduction with different inocula. However, the highest rates of sulfate reduction were found in incubations amended with camelina-JP5 [(57.2 ± 2.2)–(80.8 ± 8.1) μM/day] or its blend with petroleum-JP5 (76.7 ± 2.4 μM/day). The detection of a suite of metabolites only in the fuel-amended incubations confirmed that alkylated benzene hydrocarbons were metabolized via known anaerobic mechanisms. Most importantly, general (r2 = 0.73) and pitting (r2 = 0.69) corrosion were positively correlated with sulfate loss in the incubations. Thus, the anaerobic biodegradation of labile fuel components coupled with sulfate respiration greatly contributed to the biocorrosion of carbon steel. While all fuels were susceptible to anaerobic metabolism, special attention should be given to camelina-JP5 biofuel due to its relatively rapid biodegradation. We recommend that this biofuel be used with caution and that whenever possible extended storage periods should be avoided.
A state-of-the-art review of parameters influencing measurement and modeling of skid resistance of asphalt pavements
R B KOGBARA, E A MASAD, [...], Construction and Building materials, [MountainsMap]
A state-of-the-art review of key parameters that influence measurement and modeling of skid resistance of asphalt pavements is provided. Tire-pavement interaction/friction is discussed and the current harmonization method of friction measurements questioned. The latest developments on pavement surface texture measurement and characterization are highlighted. A critical review of aggregate properties affecting friction, the frictional properties of asphalt mixtures and the influence of environmental factors on skid resistance is presented. An overview of modeling efforts entailing different aspects of tire-pavement friction is also presented. The frictional performance of asphalt pavements largely depends on the type and quality of coarse aggregates used. The different hot mix asphalt (HMA) classifications generally have similar microtextures. Their frictional performance follows the same order as their macrotextures. There is need for experimentally-validated skid resistance prediction models, especially for warm surfaces. Such models should account for tire and pavement surface texture characteristics, and the influence of environmental factors. Some other research needs are also identified.
Minimizing inter-microscope variability in dental microwear texture analysis
S D ARMAN, P S UNGAR, [...], STMP, [MountainsMap]
A common approach to dental microwear texture analysis (DMTA) uses confocal profilometry in concert with scale-sensitive fractal analysis to help understand the diets of extinct mammals. One of the main benefits of DMTA over other methods is the repeatable, objective manner of data collection. This repeatability, however, is threatened by variation in results of DMTA of the same dental surfaces yielded by different microscopes. Here we compare DMTA data of five species of kangaroos measured on seven profilers of varying specifications. Comparison between microscopes confirms that inter-microscope differences are present, but we show that deployment of a number of automated treatments to remove measurement noise can help minimize inter-microscope differences. Applying these same treatments to a published hominin DMTA dataset shows that they alter some significant differences between dietary groups. Minimising microscope variability while maintaining interspecific dietary differences requires then that these factors are balanced in determining appropriate treatments. The process outlined here offers a solution for allowing comparison of data between microscopes, which is essential for ongoing DMTA research. In addition, the process undertaken, including considerations of other elements of DMTA protocols also promises to streamline methodology, remove measurement noise and in doing so, optimize recovery of a reliable dietary signature.
Influence of process parameters on kerf geometry and surface roughness in Nd:YAG laser cutting of Al 6061T6 alloy sheet
G LEONE, S GENNA, [...], Int J of Adv Manuf Tech, [Talymap]
In the present study, fine laser cutting of aluminium alloy 6061-T6 sheets, characterised by light reflection and heat conductivity, by means of a 150-W multimode lamp pumped Nd:YAG laser is investigated through an experimental testing campaign. Design of experiments (DoE) and analysis of variance (ANOVA) are adopted to study the influence of the process parameters on the kerf geometry and surface roughness. The results show that the laser allows cutting 1-mm-thick AA6061-T6 sheets with a cutting speed up to 700 mm/min, obtaining narrow kerfs (smaller than 200 μm), a fine taper angle (lower than 4°), a low dross height (about 40 μm) and a roughness average, Ra, around 4 μm.
Designing of Epoxy Matrix by Chemically Modified Multiwalled Carbon Nanotubes
S GANTAYAT, N SARKAR, [...], Adv in Polymer Tech, [PicoImage]
A chemical treatment was applied to functionalize multiwalled carbon nanotubes (MWCNTs) to introduce –COOH and –OH groups on the surface for better interfacial interaction with an epoxy matrix. The functionalized MWCNT (f-MWCNT) reinforced epoxy nanocomposites were prepared with varying compositions up to 1 wt% MWCNTs. The interaction between MWCNTs and epoxy matrix was evidenced by Fourier transform infrared spectroscopy. The structure and microstructure of f-MWCNTs reinforced epoxy composite were studied by X-ray diffraction, field emission scanning electron microscope, high-resolution transmission electron microscope, and Raman spectroscope. The orientation of f-MWCNT was investigated by an atomic force microscope. The incorporation of f-MWCNTs enhanced the thermal stability and the conductivity of the epoxy matrix significantly. The results of tensile strength, tensile strain, extension, and load at break clearly revealed a substantial improvement in tensile properties of the epoxy matrix due to homogeneous dispersion of f-MWCNTs in the epoxy matrix and strong interfacial adhesion between them as well. The improvement in thermal and mechanical properties in combination with an increase in electrical properties may make the material suitable for making electronic devices.
Three-dimensional surface measurement for the quantification of mechanical properties of laser-sintered parts
T GRIMM, G WITT, G WIORA, Materials Testing, [MountainsMap]
A good correlation (ρ = −0.912) is found between three dimensional surface features and mechanical properties of laser-sintered parts. This study identifies correlating surface parameters and features out of the wide range of existing evaluation methods resulting from the new possibilities of a three dimensional surface measurement in contrast to a conventional tactile profilometry. Therefore, surface analyses were performed using a confocal microscope and tensile tests according to ISO 527-1 were conducted. Especially the motifs dale and volume of islands analyses show a good correlation concerning the tensile strength, the Young´s modulus and the elongation at break. The differences with regard to each feature and their influence on the mechanical properties are discussed.
Read More: http://www.hanser-elibrary.com/doi/abs/10.3139/120.110851
Metrological changes in surface morphology of high-strength steels in manufacturing processes
G M KROLCZYK, J B KROLCZYK, [...], Measurement, [MountainsMap]
In this paper the surfaces of high-strength steels were analyzed using an optical 3D measurement system to investigate into the surface morphology and parameters of surface topography. Analyzed surfaces were generated by the most commonly used in the production facilities of manufacturing processes. The study was conducted for 400 HB plates. It was established that the behavioral changes in the manufacturing process influence the surface characteristics to a great extent. Comprehensive parametric analysis was conducted for dry production conditions. It has been observed that there exists a close correlation between mesh grit size and parameters of surface roughness Ssk and Sku in abrasive blasting processes. Furthermore the results show that the surface morphology in turning process depends to a large extent on the direction of feed motion. The study was performed within a production facility during the machining of components subject to wear.
Effect of carboxylic acid functionalized graphene on physical-chemical and biological performances of polysulfone porous films
M IONITA, L E CRICA, [...], Polymer, [SensoMap]
This study highlights the preparation and characterization of new polysulfone/carboxylic acid functionalized graphene (PSF/G-COOH) porous composite films. Materials structure, morphology, topography, hydrophilic–hydrophobic character, as well as thermal, mechanical and biological behavior were thoroughly evaluated. Raman spectrometry, X-ray diffraction and transmission electron microscopy evidenced the formation of homogenous configurations, with well-dispersed G-COOH layers within the PSF matrix. Both film sides were found to develop larger pores in the presence of G-COOH, whereas changes of selective layer thickness and macrovoids shape were also observed. Profilometry emphasized a smoothing effect imposed by G-COOH on both surfaces, ∼50% reduction of surface roughness was computed for 2 wt.% G-COOH. No significant vary was noticed for water contact angle, whereas biocomposites thermal and mechanical stability were found to be positively related to G-COOH concentrations. Biocompatibility and cell cytoskeleton assessments revealed good biocompatibility and emphasized cells affinity for G-COOH rich areas.
[PDF] Development of Low Friction Snake-Inspired Deterministic Textured Surfaces
P CUERVO, D A LOPEZ, [...], [MountainsMap]
The use of surface texturization to reduce friction in sliding interfaces has proved successful in some tribological applications. Still however, it is difficult to achieve robust surface texturing with controlled designer-functionalities. This is because the current existing gap between enabling texturization technologies and surface design paradigms. Surface engineering, however, is advanced in natural surface constructs especially within legless reptiles. Many intriguing features facilitate the tribology of such animals so that it is feasible to discover the essence of their surface construction. In this work, we report on the tribological behavior of a novel class of surfaces of
which the spatial dimensions of the textural patterns originate from micro-scale features present within the ventral scales of pre-selected snake species. Mask Lithography was used to produce implement elliptical texturizing patterns on the surface of titanium alloy (Ti6Al4V) pins. To study the tribological behavior of the texturized pins, pin-on-disc tests were carried out with the pins sliding against UHMWPE discs with no lubrication. For comparison, two non-texturized samples were also tested under the same conditions. The results show the feasibility of the texturization technique based on the COF of the textured surfaces being consistently lower than that of the nontexturized samples.
Multi-scale metrology of concrete surface morphology: Fundamentals and specificity
L SADOWSKI, T MATHIA, Construction and building materials, [MountainsMap]
Nowadays the interest in esthetical and functional aspects of concrete surfaces has considerably increased. To reach a desired functionality and level of durability of constructed and existing concrete structures, proper and improved descriptors of physical-chemical and morphological states are needed. The proper generation, treatment and characteristics of concrete surface are an important stages in building and renovation of architectural structures. Moreover, due to the complexity of heterogeneous concrete materials, the multi-scale and multi-physics approaches are discussed. The needs of specific algorithms and methods useful for the measurement and characterization of a heterogeneous concrete surface, and therefore its complexity, is demonstrated.
Manufacturing and characterization of polyether ether ketone/methyl phenyl polysiloxane composite coatings
M BARLETTA, A GISARIO, M PUOPOLO, S VESCO, J Applied Polymer Sci, [Talymap]
In this work, manufacturing and characterization of single- and multilayer polyether ether ketone (PEEK)-reinforced coatings were investigated. Hybrid composites of thermoplastic reinforcing agents in a thermoset resin was, therefore, achieved by dispersing large PEEK particles (∼85 μm diameter) in methyl phenyl polysiloxane (MPP). First, mechanism of formation of the polymeric networks during MPP curing at different temperatures (250–400 °C) was analyzed. The different arrangements of the PEEK powders inside the cross-linked network of the MPP resin were, thus, disclosed. Second, the effect of process parameters on visual appearance, morphological features, and mechanical response of the composite coatings was evaluated by contact gauge profilometry, scanning electron microscopy, IR spectrometry, and microscratch indentations. Moderate temperature curing (250 °C > T > 300 °C) of the composite coatings led to polysiloxane resins harder, well adhered on the metal and able to retain better the PEEK reinforce. Further increase in curing temperature (350 and 400 °C) might embrittle the polysiloxane resin, with the PEEK powders in it partially attenuating the loss of properties of the composite coating.
Effect of Mg doping in ZnO buffer layer on ZnO thin film devices for electronic applications
P GIRI, P CHAKRABARTI, Superlattices and Microstructures, [PicoImage]
Zinc Oxide (ZnO) thin films have been grown on p-silicon (Si) substrate using magnesium doped ZnO (Mg: ZnO) buffer layer by radio-frequency (RF) sputtering method. In this paper, we have optimized the concentration of Mg (0–5 atomic percent (at. %)) ZnO buffer layer to examine its effect on ZnO thin film based devices for electronic and optoelectronic applications. The crystalline nature, morphology and topography of the surface of the thin film have been characterized. The optical as well as electrical properties of the active ZnO film can be tailored by varying the concentration of Mg in the buffer layer. The crystallite size in the active ZnO thin film was found to increase with the Mg concentration in the buffer layer in the range of 0–3 at. % and subsequently decrease with increasing Mg atom concentration in the ZnO. The same was verified by the surface morphology and topography studies carried out with scanning electron microscope (SEM) and atomic electron microscopy (AFM) respectively. The reflectance in the visible region was measured to be less than 80% and found to decrease with increase in Mg concentration from 0 to 3 at. % in the buffer region. The optical bandgap was initially found to increase from 3.02 eV to 3.74 eV by increasing the Mg content from 0 to 3 at. % but subsequently decreases and drops down to 3.43 eV for a concentration of 5 at. %. The study of an Au:Pd/ZnO Schottky diode reveals that for optimum doping of the buffer layer the device exhibits superior rectifying behavior. The barrier height, ideality factor, rectification ratio, reverse saturation current and series resistance of the Schottky diode were extracted from the measured current voltage (I–V) characteristics.
Morphology is not Destiny: Discrepancy between Form, Function and Dietary Adaptation in Bovid Cheek Teeth
J P GAILER, I CALANDRA, E SCHULZ-KORNAS, T KAISER, J Mammalian Evol, [uSoft Analysis]
Mammal teeth have evolved morphologies that allow for the efficient mechanical processing of different foods, therefore increasing dietary energy uptake for maintenance of high metabolic demands. However, individuals masticate foods with biomechanical properties at odds with the optimal function of a given tooth morphology. Here, we investigate tooth form and function using two quantitative 3D methods at different scales on the same individuals of nine bovid species. Dental topometry quantifies the gross morphology, and therefore, reflects evolutionary adaptive patterns. Surface texture analysis infers mechanical occlusal events, which reflect the actual tooth function, and is free from the influence of morphology. We found that tough foods can be satisfactorily exploited by grazing species with enamel ridge morphologies not more complex than those found in intermediate feeders and browsers. Thus, the evolution of enamel complexity is likely determined by a balance between adaptation and constraints. Wider enamel ridges seem to be a common functional trait in bovids to compensate for severe wear from abrasive foods and/or chipping from hard foods. Our results demonstrate that supposedly essential functional adaptations in tooth morphology may not be required to process food efficiently. This emphasizes the large plasticity between “optimal” morphology and the potential function of the tooth, and underscores the need to appreciate (apparently) maladaptive structures in mammalian evolution as nevertheless effective functioning units.
A novel approach to obtain conductive tracks on PP/MWCNT nanocomposites by laser printing
G COLUCCI, C BELTRAME, [...], RSC Adv, [LeicaMap]
This article aims to develop metal free conductive tracks on polymer nanocomposites based on a polypropylene matrix in the presence of MWCNTs, by using laser printing. The main purpose is to obtain electrical wiring that can replace the metal wires commonly used for electrical transmission. A complete investigation is carried out in order to study the effect of the laser processing on the polymer matrix and the influence of the MWCNTs on the electrical and thermal properties of the polymer-based nanocomposites. The paper also describes the effect of the laser on the final microstructure of the CNTs-based nanocomposites. The results obtained clearly indicate that the laser printing is a simple, flexible, and relatively low cost approach to obtain conductive tracks on PP in the presence of MWCNTs, depending on the laser parameters set up. In fact, as found, it is strictly necessary to reach a good compromise between the electrical resistance values and the final integrity of the samples, because the laser printing treatment can induce damage on the final material because of the high energy absorbed on the polymer surface and the high temperatures generated. A circuit prototype has been also designed and developed.
High-speed thermal plasma deposition of copper coating on aluminum surface with strong substrate adhesion and low transient resistivity
A SIVKOV, Y SHANENKOVA, [...], Surface and coatings tech, [MountainsMap]
Copper and aluminum are widespread materials and have many applications, especially in the electrical engineering, and their coupling is an important issue. The direct connection of these materials without special preparation leads to increasing the transient resistance and energy loses in the contact place. This paper shows the possibility of copper deposition on aluminum substrates using high-speed thermal plasma jet, generated by a coaxial magnetoplasma accelerator. This method allows forming the uniform coating, having the thickness from 50 to 100 μm, with the strong adhesion to the substrate. It is found that in the considered system the adhesion strength depends on the speed of the material deposition and varies from 1540 MPa to 2520 MPa. Such a strong coupling is achieved due to the presence of the mixing material zone near the interface. The material mixing and the absence of clearly-seen boundary between coating and substrate provides not only the strong adhesion but also allows reducing the transient contact resistance. The value of the transient resistance can be decreased at 2.8 times in comparison with the direct connection of copper and aluminum. The surface roughness of synthesized samples and its influence on the transient contact resistance is also investigated using profilometry analysis. It is shown that increasing the compression force can positively decrease the surface roughness that leads to increasing the contact area and, respectively, to decreasing the transient resistance.
Non-mulberry silk fibroin grafted poly(ε-caprolactone) nanofibrous scaffolds mineralized by electrodeposition: an optimal delivery system for growth factors to enhance bone regeneration
P BHATTACHARJEE, D NASKAR, [...], RSC Adv, [PicoImage]
Mineralization of scaffolds enables them to mimic the chemistry of natural bone. Mineralizing nanofibrous scaffolds can successfully replicate both the architecture and chemical composition of bones and prove suitable for bone reconstruction. Non-mulberry silk fibroin (NSF) (from Antheraea mylitta) grafted poly(ε-caprolactone) (PCL) nanofibrous scaffolds (NSF-PCL) are fabricated using electrospinning, followed by aminolysis. Electrodeposition, due to its speed and simplicity is used to deposit calcium phosphate on these scaffolds at two deposition voltages: 3 V and 5 V. The deposition of nano-hydroxyapatite (nHAp) obtained is of high quality and its topology is dependent upon the voltage of electrodeposition. Along with scaffolds of nHAp deposited on a NSF-PCL matrix at 3 V and 5 V (NSF-PCL/3V and NSF-PCL/5V respectively), the unmodified NSF-PCL matrix is used as a control. The results of mechanical characterization and certain basic cell culture using the MG-63 cell line show the merits of NSF-PCL/5V over the other two compositions. The NSF-PCL/5V scaffold is then used for detailed cell culture studies after being loaded with growth factors like bone morphogenic protein-2 (rhBMP-2) and transforming growth factor beta (TGF-β) in a 1 : 1 (potency) proportion. Outcomes from these studies show a clear advantage of using a combination of the growth factors over using any one of them individually. Dual growth factor loaded matrices promote more significant expression of genes related to bone growth and better facilitate early differentiation of cells. The mineralized scaffolds thus created are mechanically suitable for bone tissue engineering and in combination with growth factors significantly enhance bioactivity, proliferation and differentiation of osteoblast-like cells. The engineered scaffolds hold the potential, with further development, to serve as an optimal alternative for bone tissue engineering.
Amorphous Alumina Barrier Coatings on Glass: MOCVD Process and Hydrothermal Aging
P L ETCHEPARE, L BAGGETTO, [...], Adv Mat Int, [PicoImage]
Amorphous alumina coatings are applied on the inner surface of glass containers aiming at improving their hydrothermal ageing barrier properties. A direct liquid injection technology is implemented in a metal-organic chemical vapor deposition (MOCVD) process to feed the reactor in a controlled and reproducible way with a solution of aluminum tri-isopropoxide (ATI) in anhydrous cyclohexane. Amorphous alumina coatings are characterized by X-ray diffraction, electron probe microanalysis, scanning electron microscopy, atomic force microscopy and scratch-test method. They are amorphous and hydroxylated at process temperatures between 360 and 420 °C and close to Al2O3 stoichiometry between 490 and 560 °C. Hydrothermal ageing simulated by a standard sterilization cycle results in the increase of the root mean square of the surface of the coatings from ≈17 to 61 nm and in the increase of the porosity without affecting the adhesion of the coatings on the glass substrates.
Compositional dependence of optical properties of zirconium, hafnium and tantalum carbides for solar absorber applications
E SANI, L MERCATELLI, [...], Solar Energy, [Talymap]
Besides ultra-refractoriness and favorable mechanical and chemical characteristics, carbides of early transition metals show intrinsic spectral selectivity, making them appealing for high-temperature solar absorber applications. However these kinds of ceramics can be produced using many processing methods resulting in different compositions, density and surface finishing. Thus the present work reports on the systematic study of microstructural, mechanical and optical properties of dense zirconium, hafnium and tantalum carbides as a function of the sintering method (high pressure or pressureless), implying use of 10 or 20 vol% of MoSi2 as sintering aid. The spectral hemispherical reflectance of Zr-, Hf- and Ta-carbides has been measured in the 0.25–16.5 μm wavelength range and correlated to the surface microstructure and roughness. Room and high temperature fracture strength has been measured as well.
Three-dimensional analysis of scale morphology in bluegill sunfish, Lepomis macrochirus
D K WAINWRIGHT, G V LAUDER, Zoology, [Talymap]
Fish scales are morphologically diverse among species, within species, and on individuals. Scales of bony fishes are often categorized into three main types: cycloid scales have smooth edges; spinoid scales have spines protruding from the body of the scale; ctenoid scales have interdigitating spines protruding from the posterior margin of the scale. For this study, we used two- and three-dimensional (2D and 3D) visualization techniques to investigate scale morphology of bluegill sunfish (Lepomis macrochirus) on different regions of the body. Micro-CT scanning was used to visualize individual scales taken from different regions, and a new technique called GelSight was used to rapidly measure the 3D surface structure and elevation profiles of in situ scale patches from different regions. We used these data to compare the surface morphology of scales from different regions, using morphological measurements and surface metrology metrics to develop a set of shape variables. We performed a discriminant function analysis to show that bluegill scales differ across the body − scales are cycloid on the opercle but ctenoid on the rest of the body, and the proportion of ctenii coverage increases ventrally on the fish. Scales on the opercle and just below the anterior spinous dorsal fin were smaller in height, length, and thickness than scales elsewhere on the body. Surface roughness did not appear to differ over the body of the fish, although scales at the start of the caudal peduncle had higher skew values than other scales, indicating they have a surface that contains more peaks than valleys. Scale shape also differs along the body, with scales near the base of the tail having a more elongated shape. This study adds to our knowledge of scale structure and diversity in fishes, and the 3D measurement of scale surface structure provides the basis for future testing of functional hypotheses relating scale morphology to locomotor performance.
Sensing performance optimization by tuning surface morphology of organic (D-π-A) dye based humidity sensor
A G AL-SEHEMI, M S AL-ASSIRI, [...], Sensors and Actuators, [PicoImage]
We present herein the effect of varied humidity levels on the electrical parameters of the (E)-2-{4-[2-(3,4,5-trimethoxybenzylidene) hydrazinyl]phenyl}ethylene-1,1,2-tricarbonitrile (TMBHPET) organic dye based humidity sensor. TMBHPET dye has been synthesized bearing an additional methoxy group substituent at the terminal benzene ring of previously reported (E)-2-(4-(2-(3,4-dimethoxybenzeylidene)hydrazinyl)phenyl)ethane-1,1,2-tricarbonitrile (DMBHPET) dye. The strategic dye design is believed to increase the π-electron polarizability in the dye structure. Capacitive type humidity sensor has been fabricated in planar geometry of Al/TMBHPET/Al and its capacitance has been monitored as a function of relative humidity (RH) level at varied frequencies of ∼1 v AC input bias. A maximum sensitivity ∼46 fF/%RH at 1 kHz has been observed which is almost seven times higher as that of DMBHPET based humidity sensor which may be attributed to the porous surface morphology of TMBHPET sensing film. The sensor has also shown reversible changes in its capacitance with variation in humidity level and hysteresis value has been observed to be 2.4%. The motive of the present study was to increase the sensing parameters of the previously reported humidity sensor utilizing DMBHPET dye, which has been successfully achieved.
Three-Component EC-SPR Biosensor Based on Graphene Oxide, SiO2 and Gold Nanoparticles in NADH Determination
J BRECZKO, E REGULSKA, [...], ECS J Solid State Sci Tech, [PicoImage]
The main goal of this paper was to develop a biosensor containing three types of structures: graphene oxide (GO), silica nanoparticles (SNs) and gold nanoparticles (GNPs) for effective electrochemical and optical determination of dihydronicotinamide adenine dinucleotide dehydrogenase (NADH). The subsequent steps in biosensor formation, the manner of structure organization and the layer thickness were verified by different methods. Electrochemical oxidation of NADH was performed with the usage of differential pulse voltammetry method (DPV). Results show that obtained biosensor catalyzes the process of NADH electrochemical oxidation. The shift of oxidation potential toward less positive values and the increment of oxidation current were clearly noted. Additionally, the oxidized NAD form was found to exhibit an electrostatic affinity to the top layer of sensor giving a possibility to SPR detection. DPV and SPR signals registered for different amount of NADH were correlated with its concentration into linear relationship: y = 8.6388x − 0.0109; R2 = 0.9997 and y = 1305.8x − 74.098; R2 = 0.9913, respectively. Enhancement of the electrochemical sensitivity toward NADH, as a result of electrode modification, was proved by lower values of LOD (0.0236 mM) and LOQ (0.0707 mM) in comparison with corresponding parameters calculated for non-modified gold electrode.
[PDF] Method for phase boundary structure control of laminated materials; destruction process investigations of nanostructured coatings with predetermined phase boundary
texture
T A KONSTANTINOVA, A I MAMMAEV, [...], IOP Conf Series, Mat Sci Eng, [MountainsMap]
New surface texturing method by means of microplasma coating deposition with the following etching of the coating was shown and described. The method of step by step microplasma texturing was proposed to control the phase boundary of laminated materials.
Micrographs of nanostructured inorganic non-metallic coating surface were obtained and analyzed before and after mechanical deformation. The nature of cracks formation and growth was investigated.
Low velocity impact response of basalt-aluminium fibre metal laminates
L FERRANTE, F SARASINI, [...], Materials & Design, [Talymap]
This work reports on a preliminary study to assess the response of fibre metal laminates (FMLs) made of stacked layers of basalt fabric epoxy prepreg and aluminium sheets to low velocity impact and, through comparison with published results for Glare materials, benchmark their impact performance. Comparison is also made with results from plates of monolithic aluminium with comparable thickness. The effect of impactor size is also investigated whilst the impact energies were selected with the aim of inducing first crack (FC) and through the thickness crack (TTT) on the FML samples. Optical microscopy and profilometry were used to elucidate fracture mechanisms and the dent depth. The response of basalt fibre metal laminates was found to be both significantly influenced by the impactor size and fairly positive, proving to be competitive with monolithic aluminium plates although some issues about the aluminium/basalt interface have been raised.
[PDF] Anodizing of Titanium coatings with different roughnesses
C SANTIVERI CARRERA, [LeicaMap]
Titanium is a metallic material that has been studied for decades because of its interesting chemical, physical and biological features. More specifically, there have been numerous efforts
in studying how the formation of ordered titanium oxide (TiO2) structures on its surface affects its properties (optical, catalytic, electrical, biocompatibility...). These structures can be obtained by several techniques, such as from anodization. This electrochemical technique allows obtaining a controlled oxide layer with the desired thickness and structure, and if certain parameters are well defined (electrolyte, potential applied, time...), ordered nanostructures. This range of structures can be obtained using a power supply controlled by a computer and a simple experimental system. The aim of this project is the electrochemical production of titanium oxide nanotubes and its characterization, as well as creating a hierarchical structure (macro->micro->nano) to see which impact has the roughness of the substrate in the bioactivity and biocompatibility of this
material.
Physicochemical and Biological Investigation of Different Structures of Carbon Coatings Deposited onto Polyurethane
W KACZOROWSKI, D BATORY, [...], Braz Arch Biol Technol, [MountainsMap]
The aim of this study was to examine the thrombogenic properties of polyurethane that was surface modified with carbon coatings. Physicochemical properties of manufactured coatings were investigated using transmission electron microscopy (TEM), atomic force microscopy (AFM), X-ray Photoelectron Spectroscopy (XPS), Raman spectroscopy and contact angle measurement methods. Samples were examined by the Impact-R method evaluating the level of platelets activation and adhesion of particular blood cell elements. The analysis of antimicrobial resistance against E. coli colonization and viability of endothelial cells showed that polyurethane modified with use of carbon layers constituted an interesting solution for biomedical application.
In vitro study on the response of RAW264.7 and MS-5 fibroblast cells on laser-induced periodic surface structures for stainless steel alloys
C McDANIEL, O GLADKOVSKAYA, [...], RSC Adv. [PicoImage]
The manner in which cells interact with a surface is mainly determined by the surface chemistry, surface charge, curvature and micro-topography of the surface. This study investigates the bio response of two metallic alloy coronary stents with Laser Induced Periodic Surface Structures (LIPSS) produced by femtosecond laser pulses at 515 nm and 1030 nm wavelengths. The study relates the bio response to changes in micro-topography and chemical composition. LIPSS were generated in this study by applying femtosecond pulses with a 500 fs pulse duration at a high repetition rate to smooth polished Platinum Stainless Steel (Pt:SS) and 316LSS stent surfaces, with an original roughness value of 2.9 ± 0.2 nm and 1.5 ± 0.2 nm respectively. LIPSS structures were formed by exposure to laser radiation slightly above the applied threshold fluence using a Gaussian laser beam in air. Experiments were performed at two different wavelengths, 1030 nm and 515 nm, to generate different periodic topographies. When the laser wavelength is increased the LIPSS period and depth also increases, thereby increasing the roughness. LIPSS features were characterized using techniques such as Atomic Force Microscopy (AFM) and X-ray Photoelectron Spectroscopy (XPS). This study identifies how LIPSS impact the attachment of monocyte cells (RAW 264.7) and fibroblast cells (MS-5) in vitro. The cellular reactions of un-textured to LIPSS surfaces were compared. It was found using Scanning Electron Microscopy (SEM) that different cells either attached or detached to LIPSS roughness (ranging from 29 nm to 50 nm). Fibroblast cells did not adhere to un-textured surfaces but formed a monolayer on LIPSS surfaces. This indicates that the LIPSS surface is non-toxic. Monocytes show a high affinity to bare un-textured surfaces and failed to firmly attach onto textured surfaces. In the case of stents, it is an advantage that the concentration of monocytes decreases when LIPSS are introduced as this can reduce thrombosis occurring. In the future, laser structured surfaces with various topographies can offer new bio-functionalities in the area of medical implants.
[PDF] Water sorption properties of sub-micron thin ionomer films
H K SHIM, Master's thesis, Queen's university, [PicoImage]
This thesis is focused on the water uptake and swelling properties of sub-micron thin ionconducting polymer (ionomer) films. One motivation for this work stems from the need to resolve the
discrepancy between high water uptake and low proton conductivity properties observed in Nafion thin films on SiO2 substrate. In addition, the effects of film thickness, substrate, ionomer equivalent weight
(EW), and annealing on the intrinsic properties of ionomer thin films were studied. Ionomer thin films were characterized using the quartz crystal microbalance (QCM) and ellipsometry for their density,
refractive index (RI), water uptake and swelling properties.
Water uptake studies showed that the effect of substrate on water uptake of Nafion thin films were not as strong as expected. Meanwhile, a thickness-dependent water uptake was observed for Nafion®
thin films. Similar trends were observed for the two low EW ionomers suggesting similar nano-structure in the thin film form. Interestingly, comparison of water uptake showed that low EW ionomers adsorb
comparable or less water than Nafion in the thin film form.
A combined QCM and ellipsometer setup was employed for the first time to simultaneously measure the water uptake and swelling, respectively as a function of humidity. All thin films appear to be affected by confinement effect as evident by the swelling dimension and volume of mixing. Thermally annealed (160 oC) Nafion thin films experienced a significant decrease in water uptake and swelling properties.
Mechanical Properties of the Thermal Barrier Coatings Made of Cobalt Alloy MAR-M509
OPIEKUN Z A, [Talymap]
This manuscript presents the microstructure, geometrical product specification, and
results of scratch tests performed on the interlayer of thermal barrier coating (TBC) with Rockwell’s intender. The TBC was provided by depositing two layers, metallic interlayer and external ceramic layer, onto a plate coating made of cobalt alloy MARM509 in plasma spraying process. Based on measurements of microhardness made with Berkovitz’s indenter using Nano Scratch-Tester (CSM Instruments), it was stated that elastic (Ee) to total energy (Ec) parameters (MIT = Ee/Ec), γ phase matrix of alloy MAR-M509 (MITγ), metallic interlayer (45% Ni–22% Co–17% Cr–16% Al–0.3% Y) (MITM), and ceramic layer (MITZrO2), are proportion, that is, 0.29:0.22:0.50. The surface of the casting was sandblasted with Al2O3 powder in an air stream before the TBC was introduced. Scratches were made along the cross section from a mould material (MAR-M509) through metallic interlayer and external ceramic layer in the TBC. Friction force, friction factor, and acoustic emission were recorded during the test. It has been proven that metallic interlayer in the TBC of ca. 200 μm thickness forms tough coating without pores with good cohesion values and very good adhesion values to the mould.
Methods of data analysis for the ball cratering test on TiN and DLC coated steel
SILVA W M, SOUZA P S, CARNEIRO J R, Mat Res, [Talymap]
Titanium nitride (TiN) coatings are widely used in machining because of its mechanical characteristics which modify the surface of the substrate increasing the capacity of load support and reduction of friction, while a coating as diamond-like carbon (DLC), which also has interesting mechanical properties, needs better attention. In this sense, the development of new coatings such as DLC is as important as wear analysis techniques. This work discusses the methods available to assess abrasive wear of coatings. For this, it has been used the data of the crater volume formed in ball cratering test and compared the difference between the specific wear coefficients of substrate and coating (ks and kc). These coefficients depend of the methods used for data analyses, thus, it has been used four equations to calculate ks and kc. Moreover, profilometry (pf) has been used to calculate the volumes, and thus ks and kc. Also, the roughness of the coatings, the thickness, the images corresponding to the crater formed, the coefficient of friction, the data obtained in wear tests due to the volume removed and, in the end, a comparison between ks and kc by different methods of data analyzes are presented.
Ceramic Heads Decrease Metal Release Caused by Head-taper Fretting and Corrosion
KOCAGOZ S B, UNDERWOOD R J, [...], Clinical orthopaedics and related research, [Talymap]
Metal release resulting from taper fretting and corrosion is a clinical concern, because wear and corrosion products may stimulate adverse local tissue reactions. Unimodular hip arthroplasties have a conical taper between the femoral head (head bore taper) and the femoral stem (stem cone taper). The use of ceramic heads has been suggested as a way of reducing the generation of wear and corrosion products from the head bore/stem cone taper junction. A previous semiquantitative study found that ceramic heads had less visual evidence of fretting-corrosion damage compared with CoCr heads; but, to our knowledge, no studies have quantified the volumetric material loss from the head bore and stem cone tapers of a matched cohort of ceramic and metal heads.
Optical properties of dense zirconium and tantalum diborides for solar thermal absorbers
SANI E, MERCATELLI L, [...], Renewable energy, [Talymap]
Ultra-high temperature ceramics (UHTCs) are interesting materials for a large variety of applications under extreme conditions. This paper reports on the production and extensive characterization of highly dense, pure zirconium and tantalum diborides, with particular interest to their potential utilization in the thermal solar energy field. Monolithic bulk samples are produced by Spark Plasma Sintering starting from elemental reactants or using metal diboride powders previously synthesized by Self-propagating High-temperature Synthesis (SHS). Microstructural and optical properties of products obtained by the two processing methods have been comparatively evaluated. We found that pure diborides show a good spectral selectivity, which is an appealing characteristic for solar absorber applications. No, or very small, differences in the optical properties have been evidenced when the two investigated processes adopted for the fabrication of dense TaB2 and ZrB2, respectively, are compared.
Abrasive Fluidized Bed (AFB) finishing of AlSi10Mg substrates manufactured by Direct Metal Laser Sintering (DMLS)
ATZENI E, BARLETTA M, {...], Additive manuf, [Talymap]
This work explores the feasibility of using the Abrasive Fluidized Bed (AFB) method to finish flat AlSi10Mg substrates manufactured by Direct Metal Laser Sintering (DMLS). Finishing was performed by rotating the substrates inside a fluidized bed of abrasives at high speeds. The interaction between the fluidized abrasives and AlSi10Mg substrates has been investigated to analyze the influence of the operational parameters, namely, abrasive type and rotational speed, on the finishing performance. The morphological features of the substrates and geometrical tolerances have been inspected by field emission gun–scanning electron microscopy (FEG–SEM) and contact gauge profilometry. After short finishing cycles, the substrates featured a smoother surface morphology, while the edges were only influenced slightly by the abrasive impacts. Abrasive Fluidized Bed (AFB) can therefore be considered a potential easy-to-automate, low cost, low time consuming and sustainable finishing technology for metal parts obtained through additive manufacturing.
Atomic layer deposited TiO2 protects porous ceramic foams from grain boundary corrosion
MÜLLER B, HAUGEN H, [...], Corrosion Sci, [SensoMap]
Intergranular corrosion causes a significant loss of compressive strength in highly porous TiO2 foams. In this study, the resistance of conformal atomic layer deposited (ALD) coatings against intergranular corrosion has been investigated. ALD coated TiO2 foams maintained 107% ± 20% and 94% ± 10% of their initial compressive strength for films deposited at 150 °C and 250 °C, respectively. After an immersion period of 28 days in 1 mM HCl, amorphous films showed greater potential in corrosion protection of polycrystalline TiO2 foams. However, anatase coatings with sufficient protection may be more beneficial for cell-material interactions.
Structural and surface properties of semitransparent and antibacterial (Cu,Ti,Nb)Ox coating
WOJCIESZAK D, MAZUR M, [...], Applied surface science, [Talymap]
In this work structural and surface properties of oxide thin-film coating based on Cu, Ti and Nb prepared by reactive magnetron sputtering have been described. During the deposition process metallic Cu, Ti and Nb targets were sputtered in oxygen plasma. Structural characterization of the film microstructure has revealed that as-prepared coating was amorphous. Due to such structure and the content of Ti and Nb the hardness of the oxide film was about 3.6 GPa, which is 40% higher as compared to metallic Cu film. Moreover, the surface roughness was below 1 nm, what resulted in receiving of hydrophobic properties. The multioxide film was transparent at the level of 40%, but due to high Cu-content its optical absorption edge was about 450 nm and had bright orange color. Optical investigation has revealed that the energy band-gap of this film was 1.41 eV, which indicates on the presence of CuO form. Moreover, the studies of antimicrobial activity showed that as-prepared film had a strong bactericidal effect for Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa, Bacillus subtilis and Enterococcus hirae, while fungicidal effect for Candida albicans was not observed. The biological activity was related to the amount of copper ions released from the surface of (Cu,Ti Nb)Ox coating, which was equal to 0.041 ppm per day.
Paleoenvironments inferred from phytoliths and Dental Microwear Texture Analyses of meso-herbivores
MERCERON G, NOVELLO A, SCOTT R S, Geobios, [LeicaMap]
The present study aims to assess the environmental conditions that prevailed during the late Miocene in the vicinity of Nikiti 2, Chalkidiki Peninsula (northern Greece). Here, a Dental Microwear Texture Analysis of three species of equids (20 specimens) and six species of bovids (76 specimens) is combined with analysis of the phytolith content of sediments from Nikiti 2. The latter analysis provided few remains of organic silica minerals; some were identified as short cells and are diagnostic of grasses. This is in accordance with previous studies of late Miocene sites in Anatolia which attested to the wide spread of grasslands in the Eastern Mediterranean at that time. Dental Microwear Texture Analysis completes the picture by exploring the diet of herbivores. This analysis concludes that Hipparion sithonis from Nikiti 2 had a diet composed of 80% of grass, making it the most committed to grazing component of the Nikiti 2 fauna. The two other equids from Nikiti 2, H. philippus and H. macedonicum, show affinities with variable grazers and mixed feeders. Among the Nikiti 2 bovids, Nisidorcas planicornis appears to have been a variable grazer and was the bovid most engaged in grazing. At the other end of the spectrum, ?Miotragocerus was least dependent on grasses. The two species of gazelles, Gazella pilgrimi and G. cf. capricornis, are best classified as mixed feeders. Tragoportax amalthea and Palaeoreas lindermayeri both plot between variable grazers and mixed feeders. The absence of browsers and the abundance of grass-eating species within the guild of meso-herbivores exclude the hypothesis of a forest during the late Miocene at Nikiti 2. Instead, it supports the existence of a savanna with grasses in a wealthy herbaceous layer together with accessible dicots (bushes, shrubs and forbs) exploited by medium-sized mammals. The absence of obligate grazers within the meso-herbivore guild suggests severe and repeated depletions of grassy vegetation (likely during seasonal droughts) forcing herbivores to widen their feeding habits to include browse. Such seasonality in food resources is consistent with paleoclimatic evidence especially with respect to seasonal changes in temperature.
Specialized Study on Morphological Features of Tungsten Carbide Thin Film Synthesis by HFCVD
JAFARI A, ALIPOUR R, [...], J of inorganic and organometallic polymers and materials, [MountainsMap]
Tungsten carbide (WC) thin film was fabricated by the hot filament chemical vapor deposition method for 10 min as time deposition at the substrate temperature of 400 and 600 °C, under vacuum in the atmospheres of 95 % argon and 5 % methane gas mixture. In this work, the substrate temperature dependence of the WC properties was discussed. X-ray diffraction was used to identify the growth of structural properties of WC thin film on the Si (100) substrate. In order to investigate the morphological features of samples; raman scattering, field emission scanning electron microscopy and cross-sectional scanning electron microscopy (cross-sectional SEM) were used. Atomic force microscopy, mountains map premium (64-bit version) and Gwyddion software analysis were also used for further investigation. In this study, the analysis of the Minkowski functionals, the motifs, the depth histograms, the statistical parameters, the texture direction and the peak count histograms of the nanostructure surface of samples were implemented. According to the analyses, the WC films had a good crystal quality without any deformity and a low residual stress. The results of this study can accurately be used for a better comprehension of the WC thin film structures and characteristics.
Influence of Environmental Humidity on the Wear and Friction of a Silica/Silicon Tribopair Lubricated with a Hydrophilic Ionic Liquid
ARCIFA A, ROSSI A, [...], Applied materials and interfaces, [SensoMap]
In this study, the tribological behavior of silica/silicon surfaces lubricated with the ionic liquid 1-ethyl-3-methylimidazolium ethylsulfate ([EMIM] EtSO4) was investigated. Tests were carried out in the presence of either humid air (45–55% relative humidity) or in a nitrogen atmosphere, and the results were compared with those obtained using pure water as a lubricant. The cross-sectional analysis of the contact area performed by focused-ion-beam scanning electron microscopy indicated the presence of cracks in the subsurface region, showing that brittle fracture contributed to wear. Sliding promoted the formation of a third body, the presence of which was indicated by optical and secondary electron microscopy. X-ray photoelectron spectroscopy showed that the third body was mostly composed of silicon oxides. The accumulation of the debris was controlled by the presence of water: in the presence of a nitrogen atmosphere, particles were trapped between the sliding surfaces, whereas in the case of humid air, the debris was progressively removed from the contact. Notably, the presence of trapped particles was associated with higher values of wear coefficients of both disks and pins. In addition, a lower roughness was observed along the direction of sliding in the case of water-containing ionic liquid. The observed trends in wear and the combined results of the various techniques, as well as the comparison with tests carried out in the presence of pure water, all point to the characteristic tribochemical reactions of water with silicon-based materials, namely, the formation of a sacrificial layer of hydrated oxide and the dissociative adsorption of water at crack tips of SiO2. In the absence of water, the lack of a tribochemical mechanism forming a sacrificial layer leads to a microfracture-dominated wear mechanism over the entire duration of the test, thus leading to more severe wear. The possible occurrence of stress-induced phase transformation of silicon during sliding is also discussed.
Quantifying Roughness of Unpaved Roads by Terrestrial Laser Scanning
ALHASAN A, WHITE D J, DE BRABANTER K, J of transportation research board, [MountainsMap]
Unpaved roads represent a major component of the roadway network in Iowa and require regular surface grading to control roughness (e.g., corrugation). This paper presents a study that shows how terrestrial laser scanning can characterize road roughness in relation to (a) a spatially analyzed international roughness index (IRI), (b) a fast Fourier transform (FFT) spectral analysis, and (c) surface texture characterization that uses statistical analysis. Algorithms are presented for each of the roughness calculations. The spatial nature of terrestrial laser scanning makes possible the determination of IRI values along any selected path within the scan area. In this study, median IRI values were used to characterize overall road roughness. To characterize the nature of road roughness, FFT was used to decompose the laser scan height spectrum. Examples are presented for unpaved road sections with a relatively smooth surface, a smooth surface with corrugations, an unsystematically rough surface, and an unsystematically rough surface with corrugations. On the basis of the observation that the surface aggregate materials were segregated, selected small regions were studied with a scan with spacing of 0.5-mm points. These scans were filtered and statistically analyzed for variations in height by using root mean square, skewness, and kurtosis parameters. These parameters were studied in relation to the values for particle size index for the surface materials of the three distinct gradations. The algorithms presented will be of value to terrestrial laser scanning users interested in characterizing unpaved roadway conditions.
Characterization of surface polishing with spindle mounted abrasive disk-type filament tool for manufacturing of machine tool sliding guideways
RAYOND N, HILL S, SOSHI M, Int J of Adv Manuf Tech, [MountainsMap]
In order to expand the regional production of machine tools which utilize precision machined sliding guideways, cubic boron nitride (CBN) hard milling may be implemented as an alternative finish process instead of conventional surface grinding. While higher material removal rates can be achieved with a milling strategy, the use of a defined cutting edge leads to surfaces with asperities. These sharp peaks quickly wear down during sliding contact, resulting in unacceptable changes in the load bearing surface of the guide. Therefore, a post process to milling must be implemented to mitigate these features. This paper investigates the use of a spindle mounted abrasive disk filament tool for producing a functional surface similar to the ground surfaces. The optimal process parameters were investigated using 2D profile measurements, followed by comparison using areal analysis of ground, milled, and polished surfaces. It was found that polishing reduces both the height and volume of asperities on the milled surface, leading to contact characteristics which were more similar to those of the conventional ground surfaces currently used for sliding guideways.
Multi-scale study of initial tool wear on textured alumina coating, and the effect of inclusions in low-alloyed steel
BEJJANI R, COLLIN M, THERSLEFF T, ODELROS S, Tribology Int, [MountainsMap]
When turning low-alloyed steel with hard inclusions, scores and grooves have been observed in the wear of the alumina coating in CVD coated cutting tools. This study focuses on detailed understanding of flank wear in the textured alumina coating and the relation to the workpiece׳s inclusions. For chip formation studies, a quick stop device has been used. A topography analysis for the worn coating was performed in the micro scale. Studies at lower scales were performed using TEM. This allowed the study of wear on the coating crystalline structure and the embedment of workpiece material on its surface. Based on the results, the mechanism behind the initial wear was analyzed and an abrasion wear model is proposed.
A note on the surface topography of profiled wood decking
CHENG K J, EVANS P D, Australian forestry, [Altimap]
Profiled wooden deck-boards with small peaks and grooves machined into their surface are preferred in many countries to flat deck-boards because profiling makes the surface less slippery and prone to checking. Numerous companies manufacture profiled decking, and in this paper we examine the variation in topography of profiled wood decking. The topography of commercial profiled decking used in seven different countries was quantified using confocal profilometry, and principal components analysis was used to explore variability in topography between profiled decking samples and relationships between them. Confocal profilometry was able to measure the topography of profiled decking. We observed large variation in the height and width of profile peaks and also their peak and groove radii. Profiled decking can be classified into three morphological groups using the ratio of radii of surface grooves to those of peaks. Two of these groups, ribbed and rippled decking have been mentioned previously, but we identify and name a third group (ribble profile) with surface topography that lies between those of ribbed and rippled profiles. Our method of classifying profiles makes it possible to identify different types of profiled decking and provides a way of systematically comparing how profile topography influences the ability of profiles to restrict the checking of wood.
Comparison of transparent objects metrology through diamond cutting edge radii measurements
AKBARI M, KNAPP W, WEGENER K, CIRP J of Manuf Sci and Tech, [LeicaMap]
The efficiency of cutting is largely influenced by cutting edge radii. When considering the correct cutting edge radius in the simulations, correct cutting characteristics can be predicted and thus the cutting process optimized. Sharpening the cutting edge of the tool to a specific optimized radius subsequently will improve the service life of the tool, workpiece quality, and performance of cutting. Measuring cutting edge radii of tools already is challenging, especially when measuring cutting edge radii of diamonds cutting tools because of their transparency and their dimension in the micrometer range. Defining a sound framework for selecting the appropriate metrology of transparent objects and clarifying the correct measurement parameters, settings, and proper sample preparation are the main achievement of current work. Tactile profilometer, confocal and focus variation light microscopy, imprinting, scanning electron microscopy (SEM) stereoscopy, and atomic force microscopy (AFM) are used to measure the cutting edge radius of diamonds. The identification of the cutting edge radii are done based on the methodology of the least square circle fit over cutting edge radius, and is determined iteratively. Estimations of uncertainties of the measurements are explained in detail and compared. The same measurement techniques and methodologies can also be applied to measure other transparent or difficult to measure materials. The results of different measurement technologies for the same diamond specimens are compared. In the end, one choice from the utilized measurement methods is suggested based on Analytic Hierarchy Process (AHP), which is one of the methods in Multiple Criteria Decision Analysis (MCDA). The selection process and the proposed set of evaluation criteria can also be applied to other measurements.
Studies on nanotribological and oxidation resistance properties of yttria stabilized zirconia (YSZ), alumina (Al2O3) based thin films developed by pulsed laser deposition
SUBHASISA N, INDRANIL M, [...], Ceramics int, [PicoImage]
The present study aims at a detailed evaluation of mechanical, tribological, and high temperature oxidation resistance (at 1000 °C under isothermal condition) properties of YSZ, and Al2O3 based thin films developed by pulsed laser deposition technique. The mechanical and tribological properties of YSZ and Al2O3 thin films showed significant improvement with increasing the deposition temperature during pulsed laser deposition process. The kinetics of oxidation was reduced due to pulsed laser deposition and Al2O3 coating offered a superior oxidation resistance property as compared to YSZ coating. However, the deposition temperature has no significant effect in reducing the TGO growth rate of the pulsed laser deposited thin films.
Multifunctional ceramic-metal biocomposites with Zinc containing antimicrobial glass coatings
ESTEBAN-TEJEDA L, SMIRNOV A, [...], Ceramics int, [Talymap]
This article presents the segment approximation method for surface topology reconstruction from white light interferogram. The method involves polynomial approximation of separate interferogram segments, and polynomial coefficients are computed at calibration stage. Metrological properties of proposed method are investigated by interferogram modeling tilted and spherical surfaces.
Metrological Array of Cyber-Physical Systems. Part 13. Segmental Approximation for Surface Topology Reconstruction
YATSYSHYN S, STADNYK B, [...], Sensors and transducers, [Talymap]
This article presents the segment approximation method for surface topology reconstruction from white light interferogram. The method involves polynomial approximation of separate interferogram segments, and polynomial coefficients are computed at calibration stage. Metrological properties of proposed method are investigated by interferogram modeling tilted and spherical surfaces.
Evaluation of surface roughness of the bracket slot floor—a 3D perspective study
AGARWAL C, VAKIL K K, [...], Progress of Orthodontics, [Talymap]
An important constituent of an orthodontic appliance is orthodontic brackets. It is either the bracket or the archwire that slides through the bracket slot, during sliding mechanics. Overcoming the friction between the two surfaces demands an important consideration in an appliance design. The present study investigated the surface roughness of four different commercially available stainless steel brackets. All tests were carried out to analyse quantitatively the morphological surface of the bracket slot floor with the help of scanning electron microscope (SEM) machine and to qualitatively analyse the average surface roughness (Sa) of the bracket slot floor with the help of a three-dimensional (3D) non-contact optical surface profilometer machine. The SEM microphotographs were evaluated with the help of visual analogue scale, the surface roughness for group A = 0—very rough surface, group C = 1—rough surface, group B = 2—smooth surface, and group D = 3—very smooth surface. Surface roughness evaluation with the 3D non-contact optical surface profilometer machine was highest for group A, followed by group C, group B and group D. Groups B and D provided smooth surface roughness; however, group D had the very smooth surface with values 0.74 and 0.75 for mesial and distal slots, respectively. Evaluation of surface roughness of the bracket slot floor with both SEM and profilometer machine led to the conclusion that the average surface roughness was highest for group A, followed by group C, group B and group D.
Effect of gear teeth finishing method on properties of teeth surface layer and its resistance to pitting wear creation
ZWOLAK J, PALCZAK A, J of central south univ, [Talymap]
This work presented the characteristics of two gear teeth finishing methods, due to the properties of gear teeth surface layer obtained at the tooth working depth. These methods are: 1) the teeth carburization, hardening to a hardness of HRC 60-62 and then grinding, 2) the soft gear shaving as the final mechanical treatment and then carburizing and hardening to the hardness of HRC60-62. This work included the test results of the contact fatigue strength carried out on the circulating power system. The Wohler curves were plotted due to the obtained results, as the basis for the practical evaluation of the considered gear finishing methods. The parameters like volume distribution of the voids, content of the retained austenite, compressive residual stress value, but also the results of contact fatigue strength tests, are more favorable for the teeth shaving method than for the teeth grinding method.
Numerical Analysis and Experimental Evaluation of Cylinder Liner Macro-Scale Surface Texturing
RENLIAN M, SALAHELDIN A M XIQUN L, WANYOU L, ASME Proc, Engine design and mech dev, [Talymap]
This work presented the characteristics of two gear teeth finishing methods, due to the properties of gear teeth surface layer obtained at the tooth working depth. These methods are: 1) the teeth carburization, hardening to a hardness of HRC 60-62 and then grinding, 2) the soft gear shaving as the final mechanical treatment and then carburizing and hardening to the hardness of HRC60-62. This work included the test results of the contact fatigue strength carried out on the circulating power system. The Wohler curves were plotted due to the obtained results, as the basis for the practical evaluation of the considered gear finishing methods. The parameters like volume distribution of the voids, content of the retained austenite, compressive residual stress value, but also the results of contact fatigue strength tests, are more favorable for the teeth shaving method than for the teeth grinding method.
Elaboration and characterization of fluorohydroxyapatite and fluoroapatite sol−gel coatings on CoCrMo alloy
COVACIU ROMONTI D, ISKA J, [...], J of alloys and compounds, [Talymap]
This work presented the characteristics of two gear teeth finishing methods, due to the properties of gear teeth surface layer obtained at the tooth working depth. These methods are: 1) the teeth carburization, hardening to a hardness of HRC 60-62 and then grinding, 2) the soft gear shaving as the final mechanical treatment and then carburizing and hardening to the hardness of HRC60-62. This work included the test results of the contact fatigue strength carried out on the circulating power system. The Wohler curves were plotted due to the obtained results, as the basis for the practical evaluation of the considered gear finishing methods. The parameters like volume distribution of the voids, content of the retained austenite, compressive residual stress value, but also the results of contact fatigue strength tests, are more favorable for the teeth shaving method than for the teeth grinding method.
Calculation of volumetric metrial loss from taper-trunnin junctions: Development and validation of a quantitative method
KOCAGOZ S, UNDERWOOD R J, [...], Orthopaedic Proc, [Talymap]
In total joint replacement devices, material loss from the taper junctions is a clinical concern. Previous studies of explanted orthopedic devices have relied on visual scoring methods to quantify the fretting-corrosion damage on the component interfaces. Previous research has shown that visual fretting-corrosion evaluation is correlated to the volume of material loss [1], but scoring is semi-qualitative and does not provide a quantitative measure of the amount of material removed from the surface. The purpose of this study was to develop and validate a quantitative method for measuring the volume of material lost from the surfaces of explanted devices at the taper-trunnion junction.
Investigation of diffractive optical element femtosecond laser machining
CHABROL G R, CICERON A, [...], Applied Surface Science, [MountainsMap]
This paper presents an explorative study on the machining of diffractive optical elements (DOEs) in transparent materials using a femtosecond laser source. A simple form of DOE, a binary phase grating with a period of 20.85 μm (σ = 0.5 μm), a groove depth and width of 0.7 μm (σ = 0.2 μm) and 8.8 μm (σ = 0.5 μm) respectively, was successfully machined in BK7. The topographic characteristics were measured by white light interferometry and scanning electron microscopy (SEM). The processing was carried out on high precision stages with an ultrafast fibre laser (350 fs) emitting a 343 nm pulse focused onto the sample with a stationary microscope objective. A diffracted efficiency of 27%, obtained with a spectro goniometer, was corroborated by the theoretical results obtained by the Fourier modal method (FMM), taking into account the measured topographic values. These encouraging results demonstrate that high-speed femtosecond laser manufacturing of DOE in bulk glasses can be achieved, opening the way to rapid prototyping of multi-layered-DOEs.
Dental microwear of sympatric rodent species sampled across habitats in southern Africa: Implications for environmental influence
BURGMAN J H E, LEICHLITER J, AVENANT N L, UNGAR P S, Integrative Zoology, [MountainsMap]
Dental microwear textures have proven to be a valuable tool for reconstructing the diets of a wide assortment of fossil vertebrates. Nevertheless, some studies have recently questioned the efficacy of this approach, suggesting that aspects of habitat unrelated to food preference, especially environmental grit load, might have a confounding effect on microwear patterning that obscures the diet signal. Here we evaluate this hypothesis by examining microwear textures of 3 extant sympatric rodent species that vary in diet breadth and are found in a variety of habitat types: Mastomys coucha, Micaelamys namaquensis and Rhabdomys pumilio. We sample each of these species from 3 distinct environmental settings in southern Africa that differ in rainfall and vegetative cover: Nama-Karoo shrublands (semi-desert) and Dry Highveld grasslands in the Free State Province of South Africa, and Afromontane (wet) grasslands in the highlands of Lesotho. While differences between habitat types are evident for some of the species, inconsistency in the pattern suggests that the microwear signal is driven by variation in foods eaten rather than grit-level per se. It is clear that, at least for species and habitats sampled in the current study, environmental grit load does not swamp diet-related microwear signatures.
Uncertainty Analysis for Emissivity Measurement at Elevated Temperatures with an Infrared Camera
HÖSER D, WALLIMANN R, VON ROHR P R, Int J of Thermophysics, [SensoMap]
The current work describes the measurement of emissivity of rock samples and black paint Pyromark 2500 within the temperature range between 230°C and 650°C together with its detailed uncertainty analysis. The infrared camera Optris PI450 was used to obtain the surface temperature of the samples. The described method is based on adjusting the emissivity of the rock sample until the temperature of the rock surface detected by the IR camera matches the temperature of a reference body. The reference body represented the tested rock sample partially coated with Pyromark 2500. The emissivity of the paint was previously determined with a technique described in this work: Pyromark 2500 was applied on a ceramic heater and heated up to a certain temperature that was calculated from measured electrical resistance of the ceramic heater (previously calibrated as a resistance thermometer). The emissivity measurement of rock samples is flexible concerning the type of sample, its size, position relative to the IR camera (distance, observation angle), and environmental conditions. Emissivities of Gotthard granite and Paradiso migmatite are reported, and they are in an agreement with emissivities of some granite samples from literature. The uncertainty of the rock sample emissivity reaches the value of 10% and the main contribution to it is related to the electrical resistance measurement of the ceramic heater.
Titanium Implant Impairment and Surrounding Muscle Cell Death Following High-Salt Diet: An In Vivo Study
LECOCQ M, FELIX M-S, [...], Plos One, [MountainsMap]
High-salt consumption has been widely described as a risk factor for cardiovascular, renal and bone functions. In the present study, the extent to which high-salt diet could influence Ti6Al4V implant surface characteristic, its adhesion to rat tibial crest, and could modify muscle cell viability of two surrounding muscles, was investigated in vivo. These parameters have also been assessed following a NMES (neuro-myoelectrostimulation) program similar to that currently used in human care following arthroplasty. After a three-week diet, a harmful effect on titanium implant surface and muscle cell viability was noted. This is probably due to salt corrosive effect on metal and then release of toxic substance around biologic tissue. Moreover, if the use of NMES with high-salt diet induced muscles damages, the latter were higher when implant was added. Unexpectedly, higher implant-to-bone adhesion was found for implanted animals receiving salt supplementation. Our in vivo study highlights the potential dangerous effect of high-salt diet in arthroplasty based on titanium prosthesis. This effect appears to be more important when high-salt diet is combined with NMES.
Pavement interface damage behavior in tension monotonic loading
KTARI R, MILLIEN A, [...], Construction and Building Materials, [MountainsMap]
The degradation of the bituminous pavement structures is due to the several external loads (climatic conditions and traffic) and the weak bond between layers. Thus, it is important to take into account the interface behavior in the pavement computational design which is never considered actually. In order to provide reliability and efficiency of the design methods, the interface characterization study is required. In this study, a monotonic tensile test was performed for better understanding of the global and local structure behavior by using the Digital Images Correlation (DIC) analysis. The obtained results allow us to characterize the constitutive law of interface and mechanical parameters such as: stiffness, damage evolution, and release rate energy.
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