Microtextural Changes Research Articles

A Comparative Study on the Texture of Exposed Aggregate Concrete (EAC) Pavements Using Different Measurement Techniques.

This paper presents issues related to the assessment of the texture of aggregate concrete (EAC) surfaces using various methods for its verification. Microtexture was assessed using the British Pendulum Tester (BPT) and Dynamic Friction Tester (DFT). Two laser profilometers were used to assess macrotexture, circular texture meter (CTM) and stationary laser profilograph (SPL), as well as the commonly known volumetric method. Measurements were carried out on left and right tracks and in between them on five test sections of expressways. Based on the analyses performed, it was found that the results obtained by the DFT were less sensitive to changes in microtexture between individual tracks compared to the results obtained by the BPT. The BPN values in the left track were lower than those in the right track. However, the difference between the DFT20 results in these spots was insignificant. Both MPD and MTD values did not show significant differences between the right and left tracks. However, some differences were observed between the MPD parameters obtained using the CTM and SPL. This resulted from the different frequency and length of the scanned surface profile. However, the differences were at an acceptable level. A very high linear correlation was obtained in the case of BPN and DFT20 values (r - 0.719), and in the case of MPD and MTD values, the correlation was almost certain (r above 0.900). Based on a comparative analysis of the models estimating mean texture depth (MTD/ETD), a significant difference was observed between models based on EAC pavement results and those based on asphalt surfaces.

Changes in detrital garnet grain morphology and microtextures during fluvial transport in the Western Carpathians revealed by scanning electron microscopy and 3D model analysis: Implication for paleoenvironmental reconstruction

Siliciclastic grain surfaces preserve an information about mechanical transport effects and/or various chemical processes that the detritus has undergone. Weathering, transport, and diagenesis leave the clear traces that may be used to interpret the paleo-environmental conditions. We aimed to detail surface analysis of detrital garnet by the proven scanning electron microscopy (SEM), X-ray micro-tomography (XRT) and subsequent morphometric analysis of derived 3D surface model. We tracked garnet morphological and surface microtextural changes during fluvial transport in an active Beňatinská voda and Sobranecký potok streams in the Western Carpathians from the place of garnet removal from the host igneous rocks to the last appearance of its fragments in the fluvial sediments. Analysed garnet grains show a range of almost complete solid solution between almandine and grossular (Alm70-73Grs15-19Prp5-6Sps2-3Adr0-3). Precise SEM analysis showed that conchoidal fractures, straight and arcuate steps, crescentic percussion marks and V-shaped cracks are main mechanical fluvial microtextures, whilst 3D surface models derived from XRT provided the information that no relationship between mechanical surface-microtextural development and mineral inclusion distribution exists. Thus, the presence of inclusions and their proximity to the grain surface have no influence on garnet destruction during its fluvial transport. Morphometric variables such as surface roughness and curvatures derived from 3D garnet model can be used to distinguish between mechanical impacts and corrosion-induced depressions. The results related to detritus behaviour in the modern streams are applicable to the ancient fluvial sediment research and can help to correctly reconstruct the paleoenvironmental and paleogeographic conditions in various areas.

Clay diagenesis and overpressure development in Upper Cretaceous and Tertiary shales of South Texas

We studied the origins of overpressure, primarily using cuttings and wireline logs, in a nearly 4 km-thick succession of Tertiary and Upper Cretaceous shales and sandstones in the northwestern Onshore Gulf of Mexico. Our goals were: a) to specifically look for the microtextural changes in shale that are often inferred, by pore-pressure specialists, to develop in overpressured shale, and b) to test the utility of cuttings for that purpose. Overpressures begin approximately 2.5 km below the present ground surface and are moderate at the base of our study interval. Much of that section has velocity and density properties that are diagnostic of unloading, excess pore pressures generated after compaction has occurred. Our cuttings-based analyses included XRD and Rock-Eval measurements. Those datasets allowed us to define the changes in mineralogy and organic content (maturity and amount) with depth. We rule out organic maturation as a significant source of overpressure and instead identify clay diagenesis (smectite-to-illite transition) as the major source of excess pore pressure. Finally, we use SEM imaging of ion-milled samples to examine and document the nano-to micron-scale textural and mineralogic changes that occurred during diagenesis. Diagenetic quartz, present as overgrowths on quartz silt grains and microquartz intergrown with illite, is associated with the changes in clay mineralogy. Some nano-to micro-porosity can be preserved locally when detrital silt or rigid diagenetic minerals (mainly quartz and pyrite in our samples) prevent physical compaction. The stratigraphic offset between the onset of overpressure and the onset of clay diagenesis is probably due to the combined effects of the broad-scale stratigraphy (the section becomes sandier at shallower depths), and the temporal changes associated with overpressure generation and dissipation. Our experiment with cuttings demonstrated the utility and limitations of their use. Finally, our results challenge some of the assumptions about shale diagenesis that can be used during pore-pressure studies.

Enhanced alumina extraction from kaolin by thermochemical activation using charcoal

The present work aims to increase the alumina percentage recovery (APR) extracted from kaolinviathe addition of 0.5–4.0 wt.% charcoal as a thermochemical fluxing agent in the lime-sintering process at 1260–1360°C. The transformation, microstructural and microtextural changes and self-disintegration performance were characterized using thermogravimetric analysis and differential scanning calorimetry, X-ray diffraction/X-ray fluorescence, scanning electron microscopy coupled with energy-dispersive spectroscopy and laser diffraction particle-size distribution analysis. The optimum enhancement of APR, from 77.7% to 87.40%, was obtained by sintering at 1360°C with the addition of 1.5% charcoal. With further increase of the charcoal content to 4%, the APR reduced to 75.6%. Combustion of ≤1.5% charcoal provided additional heat that amorphized the crystalline calcium aluminate into highly leachable amorphous phases with improved self-disintegration efficiency. Sintering at temperatures of >1360°C or with charcoal contents >4% led to mullite crystallization and decreased alumina leachability, thereby reducing the APR. Charcoal is a cost-effective and energy-efficient activator to increase the APR extracted from kaolin.

Comparison and Harmonization of the Locked-Wheel Skid Tester and the Sideway-Force Coefficient Routine Investigation Machine

Abstract Skid resistance is a characteristic of a pavement surface that is critical to pavement safety. Skid resistance can be measured with different types of equipment, but because of the differences in the system configurations and the testing methods (fixed slip, locked-wheel, sideway-force, and variable-slip), the measured friction characteristics are not the same. To compare the measurements, analysts have attempted to harmonize measurements to a common scale by integrating the effects of macrotexture and slip-speed on skid resistance. Examples of these efforts include the Penn State model, the Rado Model, the Permanent International Association of Road Congresses International Friction Index (IFI), and the Rolling Resistance, Skid Resistance, and Noise Emission (ROSANNE) Skid Resistance Index (SRI). In the United States, skid resistance is traditionally measured with a locked-wheel skid trailer (LWST), but there has been increasing interest in the use of continuous friction measurement equipment. This paper compares friction measured using a LWST ribbed tire and smooth tire with measurements collected with a Sideway-Force Routine Investigation Machine (SCRIM). The first objective is to evaluate the influence of macrotexture on the friction measured with both devices. The second objective is to compare the friction measurements using orthogonal regression (OR) and derive equations for interconversion between both devices. The findings in this paper establish that the LWST ribbed tire and the SCRIM shared similar sensitivity to changes in microtexture, whereas smooth tire was more sensitive to changes in microtexture. The direction of the OR of both devices produced a greater correlation for the SCRIM and ribbed tire than did the smooth tire. The correlation was increased when the measurements with the SCRIM and smooth tire were converted to 60 km/h using the IFI FR60 conversion. The higher correlation using FR60 conversion provides further support for the dependence of smooth tire friction on macrotexture measurements.

Q-S laser micro-drilling and multipass full-beam Q-S laser for tattoo removal \u2014 a case series

The purpose of this study was to evaluate the safety and efficacy of a new combined method of Q-S laser-assisted tattoo removal. Ten patients with 13 professional, mostly mono-chromatic black tattoos were recruited. All tattoos received the same Q-S laser treatment sequence. An objective evaluation of tattoo clearing was assessed by careful analysis of a standardized collection of digital images taken from each tattoo, 2 months after each laser session, with the help of a custom-made pigment-fading percentage photographic ruler. The percentages of pigment clearance and side effects were evaluated by 4 independent dermatologists. Patient satisfaction and perceived discomfort during and post-procedure were evaluated according to specific scales. Clinical evaluators confirmed an average photographic pigment clearance of 97% after a median 4.85 treatment sessions. The Frac-Tat® method required 40% fewer sessions compared to those calculated by Kirby-Desai estimates. Photographic assessment of laser-exposed skin quality performed 2 months after tattoo clearing was considered almost comparable with untreated peripheral skin, confirming a very low side effect score. The Frac-Tat QS laser-assisted tattoo removal sequence used in our study showed a high degree of safety and efficiency, clearing exogenous pigments in a relatively few number of sessions. Preliminary ablative photo-acoustic fractional 1064-nm Q-S laser micro-drilling was considered an essential step in optimizing tattoo removal, increasing wavelength-independent micro-columnar clearing of deeper dermal exogenous pigments. Our preliminary observations also confirmed a significant improvement of tattoo procedure-induced micro-textural changes thanks to a tissue remodeling effect induced by the 1064-nm Q-S fractional laser photo-acoustic ablation.

Effect of conditioner disc wear on frictional, thermal, kinetic and pad micro-textural attributes of interlayer dielectric and tungsten chemical mechanical planarization

A brand-new conventional diamond disc was subjected to 32 h of wear during which SEM images of active diamonds were taken, and pad cut rates (PCRs) were measured. Interlayer dielectric (ILD) wafers were polished before, midway through, and after the wear test (on a brand-new pad) at several values of polishing pressure and pad-wafer sliding velocities. Tungsten wafers were also polished midway through and after the 32 h wear. Polishing was accompanied by pad surface topography analysis via confocal microscopy. The disc experienced significant diamond tip micro-wear along with dried slurry accumulation on its substrate, causing the PCR to drop by a factor of 2. Despite this drastic change, over the duration of the wear test, there were no substantial changes in pad micro-texture, nor ILD or tungsten removal rates indicating the lack of any correlation between PCR and film removal rate during the first 32 h of wear.

Effect of a SO2 Rich Atmosphere on Tempera Paint Mock-Ups. Part 1: Accelerated Aging of Smalt and Lapis Lazuli-Based Paints

The behavior of historic tempera paints exposed to pollutant gases is an important issue when developing conservation strategies. In this work, binary tempera paint mock-ups that were made with either smalt or lapis lazuli pigments mixed with either rabbit glue or egg yolk binders were exposed to an SO2 accelerated aging test in order to find out more about the forms and mechanisms of alteration resulting from pigment-binder interaction. To this end, spectrophotometry, hyperspectral image analysis, and profilometry were used to study macro-scale, physical changes taking place on the surface of the paints, affecting color, gloss, reflectance, and roughness. Likewise, chemical and mineralogical changes were evaluated by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (ATR-FTIR), polarized light microscopy (PLM), and scanning electron microscopy with micro-analysis (SEM-EDS), which was also used to visualize micro-texture changes in the paints. The smalt-based tempera showed a higher degree of deterioration than the lapis lazuli-based tempera, in particular a notable whitening related to the precipitation of sulfate-rich salts and to binder and pigment chemical alterations. Moreover, whereas aged egg yolk-based paints showed visible color change due to damage to the oily binder and the pigments, the most evident change in rabbit glue-based paints was binder loss. The alteration suffered by the pigments varied in line with their composition; thus, smalt (blue cobalt-containing glass) grains were more sensitive to SO2 exposure than lapis lazuli-(Na,Ca)8[(S,Cl,SO4,OH)2|(Al6Si6O24)]-crystals. In the smalt grains, the SO2 test caused K+ leaching from the glass matrix, which was detected by means of K/Co ratios, but the lazurite crystals (main component of lapis lazuli) were unaffected (regardless of the binder used in the tempera). The most likely source of the crystallized sulfate rich salts were the impurities that were detected in association with the natural lapis lazuli pigment, i.e., calcite and diopside. Indeed, the precipitation of efflorescences is the main cause of the optical changes found in the smalt- and lapis lazuli-based tempera, in addition to the physical-chemical damage to the binders. The information reported here would be useful for preventive conservation, as well as for art restorers, who are planning work on paintings in which paints of this kind were used.

The influence of microtexture on the formation mechanism of nodules in Zircaloy-4 alloy tube

Corrosion resistance of Zircaloy-4 alloy tube in superheated steam at 673 K/10.3 MPa is anisotropic. A part of the surface undergoes uniform corrosion while the other suffers nodular corrosion. Narrow and wide nodules are observed after an exposure period of 3 and 30 days, respectively. A new matrix transformation method is established in order to study the formation mechanism of nodules in the cross-section (CS) of Zircaloy-4 alloy tube using the EBSD technique, while the CS perpendicular to axial direction (AD). The results reveal that the microtexture is a key factor behind the two types of corrosion. Furthermore, the oxide layers grow anisotropically over the corroded surface. A thick oxide layer forms over the nodular corrosion region on the grains with c-axis oriented in the range of 40° around tangential direction (TD), whereas a thin oxide layer over the uniform corrosion region is detected on the grains with c-axis oriented in the range of 68° around TD. In short, the anisotropic growth of oxide layer was caused by the change of microtexture of the Zr-4 alloy tube, and this anisotropic growth of oxide layer contributed to the nodules formation.

Deformation Mechanisms of 316L Austenitic Stainless Steel Tubes under Equal Channel Angular Pressing

This study investigates the deformation mechanisms of 316L austenitic stainless steel tubes processed by equal channel angular pressing (ECAP) at room temperature. Nanoindentation tests were used to study the influence of the 1-pass ECAP process on mechanical properties. The microstructure evolution of specimens subjected to 1-pass ECAP process was systematically analyzed using a variety of characterization methods. The results from microstructures observed through cross sections and longitudinal sections of deformed samples at different areas showed that the grains were refined significantly by the 1-pass ECAP process, and numerous deformation twins were generated. The microstructures also showed that the 1-pass ECAP process can cause uneven refinement of grains due to inhomogeneous strain distribution. Significant changes in grain orientation and micro-texture were found during the 1-pass ECAP process. The deformation mechanisms of samples subjected to the 1-pass ECAP process consisted of two stages: dislocation slip and twinning. The observed plastic deformation by dislocation slip occurred prior to activate twinning, and severe plastic deformation mainly occurred near grain boundaries or twin boundaries.

Influence of the Skid Resistance of Ultrathin Wearing Course with Various Types of Asphalt Binders

Ultrathin wearing course (UTWC) has been widely applied in both asphalt pavements preventive maintenance and functional overlay. This study’s objective is to evaluate the influence of different modified asphalt binders with warm mix additives on the skid resistance of UTWC and to reveal the attenuation law of skid resistance of UTWC. Three types of modified asphalt binders (Styrene‐Butadiene‐Styrene‐ (SBS‐) modified asphalt, Acrylester Rubber‐ (AR‐) modified asphalt, and SinoTPS‐modified asphalt) and sasobit warm mix asphalt additive were selected to prepare asphalt mixtures. The Model Mobile Load Simulator 3 (MMLS3) was used to simulate repeated vehicle loading and abrasion. The British Pendulum Number (BPN) and Mean Texture Depth (MTD) were chosen to evaluate the skid resistance of the UTWC. The Analysis of Range (ANOR) and Analysis of Variance (ANOVA) were used to verify the significance of asphalt binder on the antiskid performance of the UTWC. ANOR and ANOVA show that the influence of different modified asphalt binders on the skid resistance of the UTWC is significant. The SinoTPS modified asphalt mixture can maintain high texture roughness before and after abrasion, providing excellent and durable skid resistance. The influence of the addition of a warm mixing additive on the skid resistance of UTWC is not significant, and changes in microtexture mainly reflect its impact on antiskid performance. The decay curve of three modified asphalt binders of the skid resistance of the UTWC can be well fitted into an exponential function. The conclusion will play an essential role in selecting the asphalt binder in a UTWC to improve the antiskid performance.

Multifractal analysis of human canine teeth at nano scale: atomic force microscopy studies

The aim of the present study is to explore the 3-D micromorphology of human canine teeth materials using multifractal analysis through atomic force microscopy (AFM). The 3-D surfaces of ten extracted canine teeth of a group of 40 year old men were studied (enamel, inter enamel, inter dentin, and cementum) by AFM images in tapping mode and on square areas of 1 μm × 1 μm (512 × 512 points). The AFM images and surface multifractal analysis confirm the dependency of surface micromorphology to their structure–property of these materials across the length scales of the teeth structural architecture. Surface statistical parameters and hence, multifractal approach have been considered as reliable and sensitive tools for quantifying the 3-D surface microtexture changes of human canine teeth materials. The surface of inter dentin had the most irregular topography (the width spectrum Δα = 2.8361, value bigger than all the other Δα sample values), while the most regular topography (the width spectrum Δα = 2.6804, value lower than all the other sample values) was found in cementum. It has been concluded that multifractal analyses can be used as mathematical tools to explore the 3-D micromorphology of human canine teeth materials.

Growth of metastable phases during brick firing: Mineralogical and microtextural changes induced by the composition of the raw material and the presence of additives

This paper studies the mineralogical and textural changes that take place during the firing in an electric kiln at 800, 950 and 1100 °C of brick samples made with or without additives. Samples were made with a clayey raw material which was mixed with either halite or calcined diatomite sludge and then fired. These samples were then compared with control samples made without additives. Different analytical techniques (X-ray fluorescence, thermogravimetric and differential scanning calorimetric analyses, X-ray diffraction, polarized optical microscopy and scanning electron microscopy) were used to reconstruct the changes that took place inside the bricks from a mineralogical and textural point of view, changes that are similar to those that take place in nature during pyrometamorphism. The carbonates decomposed and reacted with silicates to form gehlenite, diopside and wollastonite; the plagioclase was enriched in calcium and the quartz concentration fell; the clay minerals favoured the melting of the matrix and the appearance of mullite, and K-feldspar changed from microcline to sanidine. The extent of vitrification increased in line with the increase in the firing temperature. When halite was added, new silicates appeared earlier at lower firing temperatures and molysite was formed, while the most important mineralogical difference in the bricks made with added calcined diatomite sludge was the presence of cristobalite, a component of the sludge. It is interesting to observe that the newly-formed phases contain certain chemical elements that are not normally found in their standard chemical composition.

Multifractal analysis of sputtered indium tin oxide thin film surfaces

The aim of this study was to provide important insights into the micromorphology of sputtered indium tin oxide (ITO) prepared on glass substrates by direct current (DC) magnetron sputtering at room temperature using atomic force microscopy (AFM) and multifractal analysis. The samples were annealed at 450 °C in air and were divided into five groups to discuss the results, in correlation with the ambient combinations applied, as follows: I group, using argon (Ar); II group, using argon with oxygen (Ar + O2); III group, using argon with oxygen and nitrogen (Ar + O2 + N2); IV group, using argon with oxygen and hydrogen (Ar + O2 + H2); and V group, using argon with oxygen, nitrogen and hydrogen (Ar + O2 + N2 + H2). The VI group was the reference group. AFM was used to image the surface micromorphology in tapping mode, on square areas of 2 μm × 2 μm. The ITO thin film surfaces are characterized by 3-D (three-dimensional) nanometer-scale patterns highlighted by multifractal features which reflect the process used during the fabrication of thin films. In addition, the AFM images were stereometrically analyzed, in accordance with ISO 25178-2: 2012 and ASME B46.1-2009. The results have shown that the multifractal approach in correlation with the stereometric surface analyses are efficient tools for quantifying the 3-D surface microtexture changes at different fabrication combinations.

Tensile anisotropy associated microstructural and microtextural evolution in a metastable beta titanium alloy

Tensile anisotropy behaviour of metastable beta titanium alloy β-21s (Ti–15Mo–2.7Nb–3Al–0.2Si) sheet in solution treated condition is evaluated at room temperature along three different orientation (rolling direction, 45° to rolling direction and transverse direction). In addition to fractographic studies, the microstructural and microtextural evolution is investigated in the post-tensile deformed condition through optical metallography, scanning electron microscopy (SEM) and Electron Backscattered Diffraction (EBSD). Quantification of mechanical anisotropy by evaluating the % In-Plane Anisotropy (%IPA), Anisotropic Index (δ), yield loci and plastic strain ratio indicated considerable anisotropy in strengths and ductility. Irrespective of testing orientation, the deformed microstructure is characterized by fine to coarse planar slip bands, however the slip bands observed along 45° is relatively widely spaced. The evolution of dislocation density obtained from kernel average misorientation (KAM) maps is unaffected by the tensile testing direction. Although EBSD derived Taylor factor maps revealed slip mediated deformation behaviour dominated by {110} <111> slip systems along all testing directions, the Taylor factor distribution divulged complex dependence on test orientation. Despite weak to moderate microtextural changes are noticed in α-fiber and β-fiber texture components, the textural evolution is strongly influenced by the testing orientation.

Non-destructive Measurement of the Change of Micro Texture of Alloys Using Reflectance Spectrum Analysis of Visible lights

Non-destructive Measurement of the Change of Micro Texture of Alloys Using Reflectance Spectrum Analysis of Visible lights

Effect of animal glue on mineralogy, strength and weathering resistance of calcium sulfate-based composite materials

Calcium sulfate (gypsum, bassanite, and anhydrite) has been widely used since ancient times as decorative plaster and painting grounds, often mixed with organic additives (e.g., animal glue). In order to evaluate the effect of organic additives on gypsum setting and on the product's final properties, calcium sulfate-based plaster samples, with and without the addition of animal glue, were subjected to accelerated weathering and mechanical testing. Test results were related to the samples' mineralogical composition. Animal glue improved mechanical properties and weathering resistance, but retarded gypsum setting and resulted in long-term stabilization of metastable bassanite and anhydrite. Accelerated weathering (wetting/drying cycles) resulted in changes in mineral phases and micro-texture, affecting mechanical properties and facilitating deterioration due to phase transition-related volume changes. Findings are discussed with respect to applications of calcium sulfate-based materials in conservation and rehabilitation interventions.

Intracrystalline Reaction-Induced Cracking in Olivine Evidenced by Hydration and Carbonation Experiments

In order to better understand the microtextural changes associated with serpentinization reactions, natural millimeter-sized olivine grains were experimentally reacted with alkaline NaOH and NaHCO3 solutions at a temperature of 200 °C and for durations of 3 to 12 months. During hydration experiments, dissolution and precipitation were intimately correlated in time and space, with reaction products growing in situ, either as layered veins or as nearly continuous surface cover. In contrast, carbonation experiments showed a strong decoupling between both processes leading to essentially delocalized precipitation of the reaction products away from dissolution sites. Textural analyses of the samples using scanning electron microscopy, Raman spectroscopy, and X-ray synchrotron microtomography provided experimental evidence for a cause-and-effect relationship between in situ precipitation and intracrystalline reaction-induced cracking in olivine. Juvenile cracks typically nucleated at the tip of dissolution notches or on diamond-shaped pores filled with reaction products, and propagated through the olivine crystal lattice during the course of the reaction. The occurrence of new cracks at the tip of diamond-shaped pores, but also of tiny subspherical pores lining up along microcracks, indicated that fracturation and porosity networks were mutually driven, making serpentinization an extremely efficient alteration process over time. Alternatively, our data suggested that some form of porosity also developed in absence of fracturation, thus further highlighting the remarkable efficiency and versatility of serpentinization processes.

Microstructural investigation after vacuum electrical breakdown of the W-30wt.%Cu contact material

In the present work, characteristics regarding the sub-micron scale microstructure of the W-30 wt%Cu contact material after vacuum electrical breakdown have been investigated by SEM and EDS. EBSD was also utilized to reveal the change of grain size, misorientation and micro-texture for both Cu and W phases after arc erosion. The results revealed that the arc erosion led to distinct grain refinement and intensified local misorientation strain. Besides, with the help of orientation distribution function analysis, strong peak type {112}<4–61> component was identified to be an important arc erosion texture for the first breakdown phase of Cu, which would complicate the following breakdown process during service due to the work function anisotropies.

162 Strength Degradation Mechanism of the Modified 9Cr-1Mo Steel due to Stress-induced Change of Micro Texture under High Stress at Elevated Temperatures

162 Strength Degradation Mechanism of the Modified 9Cr-1Mo Steel due to Stress-induced Change of Micro Texture under High Stress at Elevated Temperatures