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The effect of finishing rolling reduction on microstructures and textures of grain oriented silicon steel was researched by optical microscopy, zeiss ultra 55 Scanning Electron Microscope (SEM) and Electron Backscatter Diffraction (EBSD) technique severally. The results show that the grain size of hot rolled sheets and decarburized strips decreases, while the center grain size of the normalized sheet increases with the increase of the finishing rolling reduction. The pearlite content increases with the increase of the finishing rolling reduction after normalization. Compare with the previous research, the effect of finishing rolling reduction on the grain size of primary recrystal-lization is greater than that of roughing rolling reduction, and large rolling reduction is beneficial to the formation of {110}<001> texture. [ABSTRACT FROM AUTHOR]

This paper studied the strength growth characteristics of Tianjin Binhai dredger fill, considering the impact load, drainage condition, and loading way of the impact. Based on UU and scanning electron microscope tests, the strength growth mechanism of the dredger fill was studied from both macroscopic and microscopic perspectives. The results showed that there an optimal impact load under the combined action of impact load and drainage, which can enhance the strength of the dredger fill to the maximum extent, its value is close to the structural yield stress. Furthermore, the methods of 'more impact rounds and fewer impact counts' and 'first light then heavy' can obtain the best effect of foundation reinforcement. Microstructural analysis showed that, with the increase in impact loads, the pore complexity and the number of pores increased, while the porosity, the number of soil particles, the pore circumference, and the total pore area decreased. This research also showed that the increase in the strength of dredger fill was mainly reflected by the increase in the internal friction angle under the combined actions of impact load and drainage, while the change of cohesion was rather small. The mathematical relationship between the internal friction angle and the pore characteristic can be expressed by a unary function, which increases with increasing pore complexity. [ABSTRACT FROM AUTHOR]

Cyclic loading always results in great damage to the pore structure and fractal characteristics of soft soil. Scanning electron microscope (SEM) can help collect data to describe the microstructure of soft soil. This paper conducted a series of SEM tests to interpret the effect of consolidation confining pressure, circulating dynamic stress ratios and overconsolidation ratio on soil's micro-pore structure and fractal characteristics. The results demonstrate that fractal dimension can well represent the complex characteristics of the microstructure of the soil; the larger the consolidation confining pressure, the greater the cyclic dynamic stress ratio, and the greater the overconsolidation ratio, the smaller the fractal dimension number of soil samples. Finally, an empirical fitting formula for cumulative strain considering microstructure parameters is established through data fitting. [ABSTRACT FROM AUTHOR]

An experimental study was performed to investigate the effects of an acid solution on the mechanical strength and the microstructure of biocemented sand. The tests were performed on small triaxial samples extracted from a large-scale model. An acid solution composed of hydrochloric acid and Tris buffer with an initial pH of 6.6 was injected in the triaxial apparatus in different amounts. The changes of the physical and mechanical properties of the sample were studied afterwards. Triaxial drained tests with constant confining pressures were performed on the chemically treated samples in order to determine the remaining strength of the samples. Moreover, several scanning electron microscope (SEM) and X-ray microtomography observations were performed on small subsamples in order to identify the changes in the microstructure due to the chemical dissolution. The experimental results point out that the strength of the treated specimens decreases dramatically compared with that of the initial untreated specimens. Typically, a 50% strength reduction has been found for 10% of total calcite dissolution. Furthermore, the microstructural observations have shown uniform calcite dissolution at the pore scale (no preferential locations). The calcite crystal structures were damaged randomly by the chemical solution. A reduction of the spatial densities and sizes of these crystals were found from SEM and X-ray microtomography observations. Overall, no hysteretic effects were observed on the mechanical (strength) and microstructural (contact surface area) properties between the biocementation and dissolution paths. [ABSTRACT FROM AUTHOR]

Permeable pavements are engineered to temporarily store water to reduce flooding during rainfall events. Permeable pavements are distinguished primarily based on their surface materials which can vary from concrete, asphalt, clay brick, concrete pavers or plastic grids. This paper examined the effect of lightweight carbon-negative aggregates (CNA) on the behaviour of concrete intended for use as solid concrete block pavers in permeable pavements. Performance indicators targeted compressive strength, splitting tensile strength, density and water absorption. CNA were produced and sourced from manufacturing firm Carbon8 Systems in Kent U.K which applies patented accelerated carbonation technology to solidify incinerated ash into useful eco-friendly aggregates. The methodology involved substituting natural aggregates (NA) by mass, with CNA at percentages varying from 0 to 100. A scanning electron microscope was used to examine the aggregate–mortar interface. Both the compressive and tensile strengths decreased exponentially with the addition of CNA. Average 28-day compressive and splitting tensile strengths ranged from 69 MPa (10,000 PSI) to 18 MPa (2600 PSI) and 3.84 MPa (560 PSI) to 1.23 MPa (178 PSI) respectively. Density values decreased linearly with the addtion of CNA with average values ranging from 2200–2600 kg/m3. ⁠Conversely, water absorption increased with increases in CNA with average values ranging from 1.66% to 9.17%. Depending on the loading requirements, CNA can replace NA in solid permeable pavement blocks by up to 100%. [ABSTRACT FROM AUTHOR]

In this work, the influence of solution heat treatment and hot extrusion on the microstructure and corrosion behavior of as‐cast Mg−2Y−1Zn−0.4Zr−0.3Sr alloys are systematically investigated via X‐ray diffractometer, scanning electron microscope coupled with energy‐dispersive X‐ray spectroscopy, electrochemical testing, and mass loss testing. The as‐cast alloy comprises α‐Mg matrix and Mn3Y2Zn3 (W‐phase). Solution heat treatment and hot extrusion exert a conspicuous influence on the corrosion behavior of Mg−2Y−1Zn−0.4Zr−0.3Sr alloys through microstructure transformation. Both methods can remarkably improve corrosion resistance, and the as‐extruded alloys exhibit an optimal corrosion resistance of 0.0432 mg ⋅ cm−2 ⋅ h−1 via mass loss testing. The three alloys exhibit a similar corrosion mechanism, which is based on galvanic corrosion. In the later stage of corrosion, a three‐tier corrosion layer structure is formed. In combination with an array of analytical methods, the corrosion mechanisms of the three alloys are described in detail. [ABSTRACT FROM AUTHOR]

The friction welding basic principle is connecting two materials with the help of friction generated between them using pressure and frictional time. The material used for this is Ti-6AL-4V & SS-304L with aluminum interlayers. The mechanical and metallurgical experimental strengths are investigated successfully. Titanium and stainless steel joined materials are commonly used for different aerospace, chemical, automotive and nuclear applications. The primary investigation of this present work is the connection between titanium and stainless steel with an aluminum interlayer. Initially, stainless steel and aluminum joints were made, and then the aluminum other surface was connected with titanium alloy. Joined welded samples are analyzed with scanning electron microscopes. Welded joint strength and characteristics were determined with the help of the tensile test, micro hardness and impact test. These investigation results were studied and compared with previous experimental studies. [ABSTRACT FROM AUTHOR]

In this work, a novel method is presented to track site-specific microstructure evolution in metallic materials deformed biaxially along proportional and complex strain paths. A miniaturized bulge test setup featuring a removable sample holder was designed to enable incremental measurements to be performed in a scanning electron microscope, by probing the same position on the sample at different deformation levels, with electron backscatter diffraction (EBSD), electron channeling contrast imaging (ECCI) and other imaging modes. Validation experiments were performed at room temperature on samples prepared from commercial sheet metal (dual-phase steel) and foils (stainless steel). Local strain measurements with the digital image correlation technique confirmed that proportional strain paths with a strain ratio up to 5 can be investigated using elliptical dies in the bulge test holder. It is also shown how complex strain paths can be obtained using a combination of overlapping elliptical dies. Incremental EBSD and ECCI were conducted in configurations relevant for the multi-scale investigation of localized plasticity and damage mechanisms in dual-phase steel. Quantitative information regarding microstructure evolution (phase fractions, orientation fields, dislocation structures, etc.) and regarding local strain distributions could be successfully obtained. This type of data sheds light on underlying deformation mechanisms and provides opportunities to calibrate crystal plasticity models. [ABSTRACT FROM AUTHOR]

In this paper, for Q235 carbon steels in NaNO2 solutions with different concentrations of NO 2 − , a passive film composed of mainly Fe2O3 was formed on the Q235 surface, and the effects of NO 2 − concentrations on the properties of passive film were studied by electrochemical methods and microstructural analyses. The applications of electrochemical impedance spectroscopy (EIS), Mott–Schottky (MS) plot, scanning electron microscope (SEM) and X-ray photoelectron spectroscope (XPS) were carried out to characterize the resistance, defect, morphology and composition of passive film, respectively. The passive film resistance and defect, respectively, increased and decreased with the increase of NO 2 − concentration until the NO 2 − concentration was up to 0.01 M, which was the critical NO 2 − concentration of stable passivation for the Q235 surface. The relation between the electrochemical behavior and the passive film was also discussed in detail. [ABSTRACT FROM AUTHOR]

• The optimal ratio of mixed-modified silt was 1% lignin and 40% construction waste fine aggregate. • Modified silt's CBR value can satisfy the standards for subgrade filling. • The silt particle gradation was improved by the construction waste fine aggregate. • The polymers generated by lignin enhanced the silt particle's cohesion. The silt in the alluvial plain of the Yellow River is characterized by uniform particle size, high porosity, and large material compressibility, which poses a challenge for filling roadbeds in this area. The study investigated the impact of lignin and construction waste fine aggregate on the physical and mechanical properties of the modified silt. The construction waste modified silt with a fine aggregate content of 30% construction waste has good compressive strength, shear strength, and degree of consolidation. The lignin modified silt with 0.5% lignin concentration has higher compressive strength, cohesiveness, internal friction angle, and compression modulus. The fuzzy comprehensive evaluation identified the optimum proportioning of 1% lignin and 40% construction waste fine aggregate for the composite modified silt and the engineering characteristics and modification mechanism of the optimum modified silt were analyzed. The California bearing ratio (CBR) test results indicated that the value of optimum composite modified silt silt increases by 118.48% compared to the plain silt, and it meets the requirements for subgrade fill as specified in the guidelines. The scanning electron microscope (SEM) test results showed that the addition of lignin and fine aggregate improved the grain composition and enhanced the silt compactness. The study demonstrates that incorporating lignin and fine aggregate in silt material can enhance its engineering properties, thereby meeting the minimal standards of filling highway subgrades. These findings can serve as a valuable reference for enhancing the quality of silt in the region. [ABSTRACT FROM AUTHOR]

• Effects of pre-dynamic loading on hydraulic properties of undisturbed loess. • Soil water characteristic curve fitting by using van Genuchten model. • Unsaturated soil mechanics analysis related to updated soil water characteristic curve influenced by pre-dynamic loading. • Effects of pre-dynamic loading on microstructure of undisturbed loess. • Combination of MIP test and SEM test to reveal microstructural alterations. The frequent earthquakes in the loess area and the geological disasters induced by them have caused huge threats to the safety and property of the local residents, and most disasters are highly dependent on moisture in the soils. In this study, the effects of pre-dynamic loading on the hydraulic properties of loess are investigated through the variation of soil water characteristic curves, which control the interaction between soil and moisture. The results are analyzed based on the combination of mercury intrusion porosimetry (MIP) and scanning electron microscope (SEM) tests, which reveal the influence of pre-dynamic loads on microstructure, for a more comprehensive understanding. It is found that both the initial water content of soil samples and the magnitude of applied pre-dynamic loads have impacts on soil water characteristic curve (SWCC). When initial moisture content is low, the dynamic load causes the loess structure to form a seismic damage zone, resulting in downward movement of SWCC and a reduction in the air entry value. When the moisture content is high, the soil structure gets denser after vibration, leading to reversed influence. For both cases, the effect increases as the PGA amplitude increases. The outcomes of different experiments have achieved good agreement. [ABSTRACT FROM AUTHOR]

Abstract Microstructures were analyzed by an improved texture-based method using gray level co-occurrence matrices (GLCM). This method is based on a new parameter calculated from the stepwise rotation of images and thereby, calculating the values independent of the original texture orientation. The proposed method was applied on a database of etched and scanning electron microscopy (SEM)-imaged low-carbon steel microstructures that are currently extensively used for automated microstructure classification. The results on the microstructures consisting of pearlitic, lath martensitic and lower bainitic constituents revealed that the method allows a significant separation of various types of microstructures in the ideal case of square-shaped cutouts. For complete grains of the corresponding second phases, the results imply that the application of a classifier is advantageous to distinguish them with a sufficient accuracy. The robustness and workability of the method was further demonstrated by discussing the effect of varying the image resolution and contrast/brightness settings during image acquisition. It was shown that such user-dependent setting parameters do not impair the separability of the steel constituents by using the proposed method. Highlights • Microstructures were characterized based on orientation-invariant image-texture features. • A new parameter called “amplitude”, was formulated and is based on image rotation and the Haralick parameters: texture contrast, correlation, homogeneity and energy. • The proposed method is insensitive to changing image resolution and image contrast/brightness settings. [ABSTRACT FROM AUTHOR]

In the present study, polycrystalline Li-Si ferrites with the general chemical formula Li 0.5 + 0.5x Si x Fe 2.5 − 1.5x O 4 , (where; x = 0.0, 0.1, 0.2, 0.3, 0.4, 0.5 and 0.6) were prepared by high energy ball milling (HEBM) technique. The effect of Si addition on the structure and electrical properties of lithium ferrite were explored. X-ray diffraction analysis indicated that all the samples are formed in cubic spinel structure. The lattice parameter was found to decrease smoothly with increasing silicon content. The average grain size ‘D’ was determined from the scanning electron microscope (SEM) micrographs and it was found to decrease with increasing silicon substitution. In the infrared spectra, two fundamental absorption bands were observed, which are attributed to the intrinsic vibrations of tetrahedral and octahedral complexes, respectively. The wave number of the two bands shifts slightly towards higher frequency side with Si addition. The dc electrical conductivity, studied from room temperature up to 960 K in static air, increases linearly with temperature indicating the semiconducting nature of the samples. The possible mechanism for the influence of silicon substitution on the electrical properties of lithium ferrites was discussed on the basis of the hopping and small polaron models. [ABSTRACT FROM AUTHOR]

This study presents a novel method for analyzing binder distribution in a lithium-ion battery (LIB) anode. The developed method is based on scanning electron microscope (SEM) image analysis and can be used to analyze an aqueous styrene-butadiene rubber/carboxymethylated cellulose (SBR/CMC) binder system. The main advantage of this method is that it can provide large-scale cross-sections of multiple samples in a single milling process while maintaining a high-quality cross-section enabling the clear distinction of electrode components. This minimizes the issue of SEM-based analysis in the selection of a representative analysis area. The sample preparation and image acquisition processes were optimized to obtain high-quality images, and image processing procedures were developed for quantitative analysis. Osmium tetroxide (OsO 4) staining and resin embedding enabled us to achieve a smooth two-dimensional (2D) cross-section with a clear distinction of the electrode components. The milling process enabled us to produce high-quality large-scale cross-sections similar to those prepared by ion beam milling methods. It was verified that our developed method is reliable in determining the SBR content and porosity. The developed method was used to analyze the SBR distribution and pore structure of anode layers prepared at various drying temperatures. [Display omitted] • Methodology to analyze the microstructure of LIB electrode was developed. • Developed method enabled to obtain large-scale and high-quality cross-section images. • Validated the method and used to analyze LIB anodes under varying drying conditions. • Explained microstructural changes using both qualitative and quantitative analyses. [ABSTRACT FROM AUTHOR]

The comprehensive investigation results of the microstructure, mechanical properties and corrosion resistance of the Al 2 O 3 thin films deposited on hot work tool steel substrate are presented in the paper. Aluminium oxide layers were prepared using atomic layer deposition (ALD) method in temperature 150, 225 and 300 °C. The uniform structure of the investigated coatings without any visible delamination was observed as a result of measurements performed with the use of scanning electron microscope. Combined SEM, AES and ToF-SIMS studies confirmed presumed chemical composition of the layers. Despite the very low thickness (∼200 nm) the layers demonstrated an excellent adhesion to the substrate, as well as a high hardness and corrosion resistance. The best mechanical properties and corrosion resistance exhibit the layers deposited at 300 °C. The excellent properties of the ALD thin films make them suitable for various engineering and industrial applications. [ABSTRACT FROM AUTHOR]

Date fruit is a good source of bioactive compounds and natural sugar. It has the potential to be utilized as a substitute for added sugar. Although several forms of dates—such as fresh dates, date paste, and date syrup—are available in the market and used for different applications, free-flow date powder would be highly beneficial in improving shelf-life, ease of handling, and blendability with various foods prepared domestically and in industry. The objective of this study was to produce date powder in a pilot-scale spray dryer and determine its physicochemical qualities. Date powder was produced at eight processing conditions (2 carrier agents (maltodextrin (MD) and gum arabic (GA) × 2 inlet air temperature (150°C and 170°C) × 2 feedstock flow rates (25 ml/min and 40 ml/min)). To the carrier agent was added at 0.4 kg per 1.0 kg of date fruits (dry weight basis), and the feedstock to the spray dryer was prepared at 20% concentration. Date powder was obtained in all eight treatments. Color (L*a*b* values), moisture content, bulk density, wettability, solubility index, hygroscopicity, microstructure analysis (using scanning electron microscope (SEM)), and total phenolic compounds were determined for the spray-dried date powder. The physicochemical characteristics of date powder varied significantly with respect to the processing conditions. Although physical properties of date powder were significantly affected by the carrier agent, there was no difference in total phenolic compounds between date powders produced with MD and GA. An SEM study revealed that date powder produced with MD had smooth, regular-shaped spherical particles but with severe agglomeration. Date powder with GA had relatively smaller particles of irregular sphere with dented surfaces. [ABSTRACT FROM AUTHOR]

Production of ceramic bricks from mixtures of ceramic industry wastes (up to 50 wt%) from the area of Vriddhachalam, Cuddalore district, Tamilnadu, India and kaolinitic clay from Thiruvananthapuram district, Kerala were investigated. The firing behavior of the ceramic mixtures was studied by determining their changes in mineralogy and basic ceramic properties such as water absorption, porosity, compressive strength and firing shrinkage at temperatures ranging from 900 to 1200 °C in short firing cycles. The effect of the rejects addition gradually up to 50 wt% was analyzed with the variation of temperature on the mechanical properties and microstructure of the bricks. The highest compressive strength and lowest water absorption is observed for the sample with 40% rejects at 1100 °C which is supported by the results of SEM analysis. The resulting ceramic bricks exhibit features that suggest possibilities of using the ceramic rejects in the conventional brick making methods. [ABSTRACT FROM AUTHOR]

Abstract: Understanding the microstructure of expansive soils is of vital importance in physical interpretation and mechanical modeling of expansive soil behavior at the macro scale. To approach this objective, two natural expansive soils were compacted and imaged to disclose their microstructure using both conventional scanning electron microscopy (SEM) and environmental scanning electron microscopy (ESEM). The micrographs of the samples at their initial compacted state showed comparable results when using SEM and ESEM techniques. The structural changes in response to two wetting-drying cycles were monitored through the ESEM experiments in order to simulate the volumetric evolution at the macro scale. Despite the significant macroscopic volume changes, it was difficult to detect structural changes at the micro scale. The ESEM test results only qualitatively described structural shrinkage upon the first drying cycle but showed little structural modification thereafter, due to the limited duration of vapor exchange between the chamber atmosphere and the sample under the microscope. In addition, the combined effects of plasticity and original microstructure determined how the microstructure evolved as a function of sample consolidation. Based on the analysis of results, limitations of both SEM and ESEM approaches in microstructural investigations of expansive soils are discussed and summarized. [Copyright &y& Elsevier]

The MgO thin films are deposited at various inclined angles. The morphology investigated by scanning electron microscope (SEM) shows the MgO thin films deposited at high inclined angles have columnar grain. The relationships between full width high maximum (FWHM) of ω-scan, residual stresses and the inclined angles are studied. The results show the smallest FWHM of MgO (002) is 4.968°, the residual stress of MgO thin films is compressive stress, and the residual stress of MgO thin films deposited at the inclined angle of 55° is the smallest. So the microstructures of MgO thin films fabricated by the oblique angle deposition (OAD) technique effectively control the residual stresses. [ABSTRACT FROM AUTHOR]

Within the scope of experiments, the effect of stitch yarn type (aramid, glass and nylon), and biaxial, warp and weft, and yarn type (aramid and glass) was investigated in the biaxial weft-knitted (BWK) composites. Five different types of composite panel, which include fiber contents, such as glass-glass-glass, glass-glass nylon, glass glass aramid, aramid glass aramid and aramid aramid aramid were fabricated by hand lay-up method. After production of composite panels, tensile, three-point bending and three-point, bending impact tests were conducted on specimens. Microstructural characterization of tested materials was performed using a scanning electron microscope. This study showed that composites with BWK preforms consisting of fiber combinations, such as aramid-aramid-aramid, had higher tensile strength (in course direction), of aramid-glass-aramid had higher bending strength (in course direction), and of glass glass aramid had higher three-point bending impact properties (in course and wale directions) than other types of tested composite structures. [ABSTRACT FROM AUTHOR]

Highlights: [•] This study has established the usefulness of optical microscopy as well as SEM study for better study of heat-altered coals. [•] Differentiation of microtextures and microstructures and contact metamorphic associations were studied. [•] Anisotropy proved supplementary tool to SEM and enabled study of minerals and baked coal in 3-D view. [•] Through this study, combined maceral–mineral analysis is helpful in coal geological studies. [ABSTRACT FROM AUTHOR]

The presented paper aims to describe the influence of accelerating admixtures on the properties and microstructure of cement pastes and mortars. Blended slag cement CEM II/B-S containing two different clinkers (differing amounts of siliceous and aluminous phases) and four types of accelerators (calcium nitrate, sodium hydroxide, cement kiln dust, and crystal seeds) were used in research. Compressive strength tests (after 12, 24, 48 h of curing), Scanning Electron Microscope (SEM) observations together with an Energy Dispersive Spectroscopy (EDS) analysis, Mercury Intrusion Porosimetry (MIP) tests, and X-ray diffraction (XRD) analysis were conducted. Results have shown that SEM and EDS examination of the microstructure of cement pastes modified with accelerating admixtures at the observed points did not reveal differences that would be sufficient to explain the changes in compressive strength. Still, the increase in amorphous phase content indicates a faster hydration reaction rate for all pastes modified with accelerating admixture. It is backed up also by lower non-hydrated compounds content. All admixtures accelerate the hydration reaction of calcium silicate phases of cement, but only NaOH and cement kiln dust (CKD) influence the aluminate phase reaction rate. The pore volume is independent of the clinker type, while the pore size distribution is not. [ABSTRACT FROM AUTHOR]

Abstract: Portland cement paste, a porous material with a multi-scale structure, consists of unhydrated clinker, hydration products and pores. At elevated temperatures, the structure of Portland cement paste changes, which might affect the strength and permeability of cement paste. This paper investigates the structure of heated Portland cement paste by means of scanning election microscope, mercury intrusion porosimetry and nitrogen adsorption, respectively. The structures of cement paste at different scales, i.e., nano-, micro- and meso-scale, determined by various methods are compared and discussed. At microscale (0.1–100μm), the capillary pore volume in heated cement paste increases slightly at temperatures from 105°C to 400°C, and increases dramatically at temperatures beyond 500°C. The cracking in heated cement paste is caused by the dehydration-induced volume change of hydration products. At nanoscale (2–100nm), the structure of C–S–H mainly remains constant at temperatures from 105°C to 400°C, and is partly transformed from gel structure to crystalline particles at temperatures beyond 500°C. The size of crystalline particles increases with the increase of temperature. At atomic scale (<2nm), the tobermorite-like C–S–H starts to be transformed into belite (β-C2S) at 500°C. [Copyright &y& Elsevier]

Achenes morphology in Potentilla L., i.e. P. subarenaria Borbás ex Zimmeter and P. intermedia L. non Wahlenb. was examined with stereoscope and scanning electron microscope (SEM). Achenes of these taxa varied in shape, size, colour, the surface sculpture and in the dimensions of dorsal ridge and ribs. SEM analyses allowed distinguishing two morphological types of seed coats pattern: ruminate-reticulate sculpture due to well preserved epidermal cells in P. subarenaria and tuberculate sculpture in P. intermedia. The main taxonomic features of these two taxa are: the microstructure, size, shape and colour of achenes. [ABSTRACT FROM AUTHOR]

Abstract: Hydrometallurgical facilities refining nickel sulfide ores produce waste residues in the form of sludges which contain concentrations of metals as well as iron and sulfur-bearing minerals and phases. The geochemical and mineralogical character of hydrometallurgical residues is important for the management of this type of industrial waste. Scanning Electron Microscope (SEM) and X-Ray Diffraction (XRD) analysis indicate that the minerals produced in the process are principally gypsum and the iron oxides, hematite and magnetite, iron hydroxides and residual sulfur and sulfides in the form of FeS, chalcopyrite, pyrrhotite and pentlandite. The iron oxide particles in the leach residue exhibit an atypical framboidal structure that is relevant to its metal leaching properties. The mineralogy and microstructure of mini plant residue is compared to that of the demonstration plant residue through the SEM and XRD. Sequential extractions are used to determine the association between different phases/minerals and select metals in each residue. [Copyright &y& Elsevier]

Aim To evaluate the effect of acid-etch procedures on the compressive strength and surface microhardness of tooth-coloured mineral trioxide aggregate (MTA). Methodology White ProRoot MTA (Dentsply Tulsa Dental) was mixed and packed into cylindrical tubes of 4 mm in diameter and 6 mm in height. Three groups, each of 15 specimens were subjected to an acid-etch procedure either 4, 24 or 96 h after mixing. The compressive strength was measured and compared with unetched control groups. Differences between groups were analysed using the Kruskall–Wallis test. A further batch of cylindrical specimens of 6 mm in diameter and 12 mm in height were prepared for testing surface microhardness. Three groups of 15 specimens were subjected to the acid-etch procedure at either 4, 24 or 96 h following mixing. Data were subjected to one-wayanova. Changes in the surface microstructure before and after the acid-etch procedures were analysed using a scanning electron microscope (SEM). Results There was a general trend for the compressive strength and surface microhardness of specimens to increase with time. In terms of compressive strength, the increase was significant between 4 h and the other time periods for both experimental and control groups ( P < 0.0001); however, there was no significant difference between 24 and 96 h. The increase in surface microhardness was significant between 4, 24 and 96 h ( P < 0.0001). In addition, there was a significant difference between experimental and control groups at all time periods ( P < 0.0001). SEM examination revealed morphological differences between the intact and the etched MTA surfaces. Conclusions Acid-etch procedures affected the compressive strength and surface microhardness of ProRoot MTA. This indicates that it may be better to postpone restorative procedures for at least 96 h after mixing MTA. Etching created surface changes that might have the potential to enhance bonding of resinous materials. [ABSTRACT FROM AUTHOR]

In this study, diaza-crown ether and phosphaze-crown ethers have been investigated in scanning electron microscope (SEM) and compared to their electron micrographs. In analysis of micrograph have been observed that compounds has different morphological structure [ABSTRACT FROM AUTHOR]

In this research, Nitzschia palea from Bacillariophyta division (in samples which received from surroundings Tokat-Turkey) have been cultured in culture medium and investigated in scanning electron microscope (SEM). In analysis of micrograph have been observed that polar nodule has different morphological structure. [ABSTRACT FROM AUTHOR]

A section of a fractured spindle from an axle housing was metallurgically examined. The axle fractured at the friction weld (FRW) interface and was from a truck with only about 8,000 miles of service. SEM and metallographic examinations of the weld fracture revealed that a ferritic band existed at the weld interface. A significant amount of oxides and some micro-porosity was observed in the ferrite. The existence of this type of microstructure compromised the strength of the weld and resulted in the overload fracture of the axle. FRW is supposed to be a solid-state process; however, melting-solidification was evident in this case, as suggested by the band of oxides caused by liquid phase oxidation of the molten layer at the interface and micro-shrinkage porosity formed during solidification of the liquid film. Process conditions that resulted in high heat input and liquidizing of the weld interface before the upsetting stage of the friction welding process should be mitigated. [ABSTRACT FROM AUTHOR]

The microscopic structure of rough rice kernel has been investigated using Scanning Electron Microscope (SEM) after solar drying in order to identify the mechanisms of the initiation and propagation of stress induced cracks. The structure of the endosperm tissue of rice kernel has been found damaged slightly due to drying. Stress induced cracks were evident. The cracks were also found between the seed capsule and the endosperm tissue. The cracks appeared to have initiated at the center of endosperm tissue and then propagated. When stress induced cracks are produced, both sides of the endosperm tissue are damaged. Most of these cracks are propagated along the edge of the starch granule through to the cell walls. These observations are a part of a series of the studies which provide useful information for practical control or minimization of the crack formation in keeping the grade of the dried rice high. [ABSTRACT FROM AUTHOR]

Abstract: The surface of the depleted uranium (DU)-0.75wt.% titanium alloy has been studied using scanning electron microscopy, energy dispersive spectroscopy and optical microscopy. The samples were examined after mechanical polishing and again after nitric acid cleaning. The acicular martensitic microstructure is revealed after chemical etching. Several of the impurities have been identified and their prevalence has been found to change depending on the surface treatments. The impurities have also been found to vary from sample to sample and within the same sample. The electrochemistry and corrosion characteristics of the alloy were studied using open circuit potential measurements and potentiodynamic polarization techniques. This study has been directed towards developing environmentally friendly protective coatings for this alloy. In this paper, we discuss our efforts in finding suitable chemical species to act as inhibitors and activators during coating formation. The effect of various oxyanions, MoO4 2−, PO4 3−, VO4 3−, MnO4−, SiO4 4− and WO4 2−, on the electrochemical behavior of the depleted uranium alloy in quiescent nitric acid has been explored including their ability to inhibit corrosion. Results indicate that chemical or electrochemical activation of the DU alloy in 0.1M HNO3 +0.025M MoO4 2− can lead to the formation of a rudimentary coating. The effect of several fluorine compounds was also examined and their electrochemical response indicates that several of them may have a potential use as a surface activator. [Copyright &y& Elsevier]

Abstract: Micro/nanostructures based on the metal–organic complex Cu–TCNQ were successfully synthesized by a novel method: vapor-induced reaction. Scanning electron microscopy was used to investigate the morphology on the three different parts of the substrate: the hot reaction area, a transitional reaction area and an induced reaction area. The results show that the morphology of the as-grown structures evolves from microstructures to nanostructures. The formation mechanism of these different structures may be understood from electrochemical principles and the decreasing concentration of TCNQ. [Copyright &y& Elsevier]

Representative and quantitative microstructural information of cement-based materials can be obtained in the backscattered electron and X-ray modes of the scanning electron microscope (SEM). One prerequisite, of several, is to use flat specimens. Microstructures that are minimally affected by the grinding and polishing necessary to produce the flat surface can be obtained. It is essential to fill the pores of the specimen with epoxy resin prior to grinding and polishing. After hardening, the epoxy stabilizes the microstructure and enables it to withstand the stresses of grinding and polishing without alteration. In the present paper, we describe a preparation technique that we consider to have produced excellent polished specimens. The importance of epoxy impregnation is demonstrated. [Copyright &y& Elsevier]

The scanning electron microscope (SEM) was successfully used to study the effects of toiletry treatment with shampoo on the microstructure of hair. This paper describes the use of SEM for comparing the conditioning effects of herbal shampoos. Commercially available herbal shampoos are not completely natural, but contain herbal extracts in a synthetic detergent base, along with other chemical additives. Completely natural shampoos were formulated in the laboratory and their conditioning effects were evaluated by comparing with a commercially available herbal shampoo. The micrographs were studied quantitatively using ‘Image Analyser Software’ and the extent to which the hair scales were uplifted was measured. The results obtained from the quantitative comparison were in agreement with those obtained from other tests, such as protein loss determination. The damage caused to the hair due to sodium lauryl sulphate was visible in the micrographs. The laboratory formulations were found to be better than the commercially available product. Thus, quantitative measurements from SEM micrographs are a valuable tool to compare the conditioning effects of hair care products. [ABSTRACT FROM AUTHOR]

A method for accurate dimensional and angular measurements of microstructures analysed in the scanning electron microscope is described. The method considers central and parallel projections and involves (a) digital image acquisition of stereopaired images from the scanning electron microscope's photodisplay, (b) generation of 3D-image representations, (c) setting of measuring points in the digitized stereopaired images, (d) computation of exact space coordinates (x/y/z) from the corresponding point coordinates (xL/yL; xR/yR), (e) determination of distances and angles between consecutive corresponding points using vector equations, and (f) transfer of computed data into spreadsheets of the data analysis software using dynamic data exchange with simultaneous graphical display of the frequency distribution of variables. Measurements performed on specimens with known dimensions (grid with 10 μm wide square meshes, polystyrene beads with 0.33 μm diameter) and angles (synthetic crystals of K(Al,Cr)[SO4], CuSO4.5H2O and NaCl) revealed a high accuracy in dimensional as well as angular measurements (total error 1 ± 0.5%). In Monte Carlo experiments the overall error was found to depend strongly on the size of the measured structure relative to the size of the measurement field (field width). [ABSTRACT FROM AUTHOR]

The inorganic structure formed at the stage of setting of the geopolymer binder ensures high durability of the material under high-temperature conditions. However, changes in the microstructure of the material are observed. The purpose of the study was to analyze changes in the structure of geopolymer mortar after exposure to high temperatures T = 200, 400, 600, 800, and 1000 °C. Mortars with a binder based solely on fly ash (FA) and mixed in the 1:1 ratio with a binder containing fly ash and ground granulated blast-furnace slag (GGBFS) were tested. The descriptions of their microstructures were prepared based on digital microscope observations, scanning electron microscope (SEM) observations, EDS (energy dispersive spectroscopy) analysis, and mercury intrusion porosimetry (MIP) porosity test results. Changes in the material due to high temperature were observed. The differences in the microstructure of the samples are also visible in the materials that were not exposed to temperature, which was influenced by the composition of the materials. Porosity increases with increasing annealing temperature. The distribution of individual pores also changes. In both materials, the proportion of pores larger than 1000 nm increases with the temperature increase. Moreover, the number of cracks and their width also increases, reaching 20 µm in the case of GGBFS. Furthermore, the color of geopolymers has changed. The obtained results extend the current state of knowledge in the field of changes in the microstructure of geopolymers subjected to high temperature. [ABSTRACT FROM AUTHOR]

Abstract: Dual phase steels are a class of steels characterized by a microstructure consisting of a soft ferrite matrix with hard martensite islands at the grain boundaries. The temperature in the dual phase (α+γ) region and the holding time are two important parameters in the intercritically annealing process. In this study, different grades of commercial low alloy steels have been heat treated to a constant annealing temperature by changing the holding time. It is observed that the effect of holding time is dependent on the steel composition. In this context, a microstructural examination has been carried out using optical, scanning electron microscope and electron probe micro-analysis and hardness values have been determined. [Copyright &y& Elsevier]

Image analysis may represent a powerful tool to accurately quantify and rapidly process digital pictures from high-resolution images by scanning electron microscope (SEM). Nine traditional Sicilian cheese varieties, five pressed and four pasta filata, were observed by SEM to quantitatively characterize the porosity of their microstructure. Freeze-fracture sampling procedure according to McManus et al. (1993) was used. Ten sequential images, from two random fields of each specimen, were recorded at 500X and 1000X in order to obtain a more complete observation of the microstructure of each cheese. The obtained images were then analyzed using a Java language tool written as a plug-in of the ImageJ software. Gray-scale images were binarized using the threshold function, after having applied specific filters to remove noise, and alterations produced by the acquisition system. Images were firstly processed using a despeckle and then a Gaussian smoothing filter to remove noise. A further band-pass filter was applied to flatten lighting effects by cutting off high and low frequencies. A radius one erode filter before and a dilate-filter after thresholding were finally applied to regularize the pore shape and enhance borders. The processed images were then automatically measured to calculate microstructure porosity. No significant differences were found among the different magnitude factors. Pressed cheeses showed higher overall porosity (P < 0.01) than pasta filata cheeses, 0.15 vs. 0.24. Among the pressed cheeses it was observed a significant (P < 0.01) porosity variation ranging from 20.7% for Maiorchino, 16 mo aged hard cheese, to 29.8% for Fiore Sicano, 1 mo aged soft cheese. Similar porosity variation was observed on pasta filata cheeses, ranging from 11% for Provola dei Nebrodi, 3 mo aged semi-hard cheese, to 22% for Ragusano cheese, 9 mo aged. Three-dimensional analysis through X-ray microtomography could be used to further study without altering the internal microstructure of cheeses. [ABSTRACT FROM AUTHOR]

Nine traditional Sicilian cheese varieties, five pressed and four pasta filata cheeses, at the best commercial representative ripening age, were analyzed by SEM. The cheeses had different peculiar shapes and hardness. They were cylindrical for the pressed cheeses (Sicilian Pecorino P.D.O., Maiorchino, and Tuma Persa hard cheeses, Piacentinu Ennese semi-hard cheese, Fiore Sicano soft cheese), parallelepiped for the pasta filata hard cheeses (Ragusano P.D.O. and Palermintano), pear like surmounted by a short neck with a ball head for the semi-hard pasta filata cheese (Provola dei Nebrodi), and disc like for the other fresh soft pasta filata (Vastedda del Belice). The sampling was done using a cheese trier by extracting a cheese core; three rectangular strips (approximately 1 x 3 x 8 mm) were cut from the medial region of each core and were prepared according to McManus et al. (1993) procedure. Samples were then dried in a critical point drying apparatus, mounted on aluminum stubs, sputter coated with gold-palladium for 15 s, and observed by SEM at 15 kV. A series of sequential images, from two fields, were recorded at 500X and 1000X magnification. As expected, significant differences on the cheeses microstructure between the pressed and pasta filata cheeses were detected. Differences were observed also within each of the above cheese categories. The pressed cheeses showed a protein matrix sponge-like structure permeated by a well distributed system of empty spaces that were originally occupied by fat globules and whey. Casein micelles join each other to form clusters and strands with no defined orientation. These amorphous texture of Sicilian pressed cheeses have been observed also in other pressed cheeses. Pasta filata cheeses showed a fibrous structure (long fiber) as a result of curd stretching. Stretching transforms the amorphous 3-dimensional protein matrix into a network of parallelaligned protein fibers. Casein molecules interact and bind each other to form a long sheaves uniformly oriented in one direction. [ABSTRACT FROM AUTHOR]

Characterization of microstructures containing small grains or low-angle grain boundaries by electron backscattered diffraction (EBSD) is limited by the spatial and angular resolution limits of the technique. It was found that the best effective spatial resolution (60 nm) for aluminium alloys in a tungsten-filament scanning electron microscope (SEM) was obtained for an intermediate probe current which provided a compromise between pattern quality and specimen interaction volume. The same specimens and EBSD equipment when used with a field-emission gun SEM showed an improvement in spatial resolution by a factor of 2–3. For characterizing low-angle boundary microstructures, the precision of determining relative orientations is a limiting factor. It was found that the orientation noise was directly related to the probe current and this was interpreted in terms of the effect of probe current on the quality of the diffraction patterns. [ABSTRACT FROM AUTHOR]