Scanning Electron Microscopy-energy Dispersive X-ray Spectroscopy Research Articles

The Metallic Sounds: A Microanalytical Study on the Production of Armenian Church Bells from Iran.

There are a considerable number of church bells in museums, examples include the museum of the Vank Cathedral and the Treasury of Armenian Music in New Julfa, both located in Isfahan, Iran. These objects were collected from different Armenian churches and cathedrals in Iran and were dated to ca. 400-100 years ago. Due to the long history of Armenians in Iran and their important role in its cultural and architectural development, study of the production technologies they utilized is a subject of interest for art historians and scientists. Three metallic bells from the Treasury of Armenian Music in New Julfa were selected for a multianalytical study to investigate their manufacturing methods, using micro-XRF, scanning electron microscopy-energy dispersive X-ray spectroscopy (SEM-EDS), and metallography techniques. The results showed that the bells were produced with a binary tin bronze alloy with 13 to 20 wt% of tin, classified as either low-tin or high-tin bronze, depending on the concentration. The analysis showed a two-phase cast microstructure consisting of the α solid solution with significant amounts of interdendritic α + δ eutectoid. The results also indicate that the bells are cast first, but some evidence of complementary thermomechanical operations is visible in their microstructure.

Chemical weathering intensity controls the accumulation of nickel in rice (Oryza sativa L.) cultivated in basalt-derived paddy fields

Globally, a high concentration of nickel (Ni) in agricultural soil is closely related to basalt weathering. Rice grains readily accumulate Ni, however, the evolution of Ni distribution and mobility in paddy fields with basalt weathering remain unclear. This study investigated the distribution, geochemical fraction, and mobilization of Ni in basalt bedrock-paddy soil-rice plant continuums under contrasting climates through a combination of field surveys, chemical extractions, X-ray diffraction, and scanning electron microscopy-energy dispersive X-ray spectroscopy (SEM-EDS) analyses. Results show that the soils developed in tropical climates were more enriched in Ni than those in temperate climates. The concentration of Ni in rice grains from the studied temperate regions (3.71 ± 2.01 mg/kg) was higher than that in the tropical regions (0.57 ± 0.37 mg/kg). The concentration of Ni bound to Fe (hydro)oxides in paddy soils from temperate regions was five times higher than that in tropical regions. In contrast, the concentration of Ni found in phyllosilicate clays (mainly smectite/illite) in paddy soils from the temperate regions was only ∼1/4 of that of clay (mainly kaolinite) in the tropical paddy soils, and the ratio of Ni concentration in phyllosilicate clays to highly reactive Fe (hydro)oxides in paddy topsoil in temperate regions was one order of magnitude less than that in tropical regions, which contributes to the low bioavailability of Ni in tropical paddy soils. Furthermore, the accumulation of Ni in rice grains was insensitive to soil pH in tropical regions but showed significant negative correlations with the degree of chemical weathering (chemical index of alteration and index of laterisation) in temperate and tropical regions. These observations support the hypothesis that chemical weathering and the dissolution–recrystallization of Fe (hydro)oxides induced by frequent redox fluctuations in paddy soils cause Ni repartition between Fe (hydro)oxides and phyllosilicate minerals, which influence Ni geochemical cycling and bioavailability, and fundamentally regulate Ni accumulation in rice. This study elucidates the mechanism and controlling factors underlying Ni partition in the basalt-paddy soil-rice plant continuum under distinct climates, providing new insights into the understanding of geochemical behavior and environmental fate of Ni.

Novel Hyperbranched Dialdehyde Carboxymethyl Cellulose-Grafted Gelatin Films as Potential Natural Antibacterial Materials

Carboxymethyl cellulose (CMC) has potential applications in food packaging given its good processibility and biological properties. In this research, dialdehyde carboxymethyl cellulose (DCMC) was first modified with polyamidoamine (PAMAM G0) to synthesize hyperbranched dialdehyde carboxymethyl cellulose (HPD). Then, a novel hyperbranched dialdehyde carboxymethyl cellulose-grafted gelatin (HPD/Gs) film was obtained by the “one-pot” method. The structural characteristics, degree of cross-linking, thickness, swelling behavior, water solubility, water vapor permeability, surface morphology, hydrophilicity, mechanical strength, antibacterial properties, and biocompatibility of HPD/Gs were characterized by using Fourier transform infrared (FTIR), scanning electron microscopy energy-dispersive X-ray spectroscopy (SEM-EDS), X-ray diffractometry (XRD), thermogravimetric analysis/derivative thermogravimetry (TGA/DTG), differential scanning calorimetry (DSC), and other analysis technologies. The results revealed that the prepared HPD/Gs film showed good thermal stability and mechanical properties. In particular, when the mass ratio of HPD to G was 1:1.5, the cross-linking degree, swelling behaviors, water vapor permeability (WVP), water contact angle, tensile strength, and elongation at break of the HPD/1.5G film reached 42.757%, 109.114%, 46.71 g·mm/m2·day·kPa (1 day), 115.4 ± 4.5°, 1.77 MPa, and 320.93%, respectively. Moreover, the HPD/Gs films had good cytocompatibility and antibacterial properties against Staphylococcus aureus and Escherichia coli. The research indicated that the designed HPD/Gs are a type of green antimicrobial material with potential value.

Biologically-induced synthetic manganese carbonate precipitate (BISMCP) for potential applications in heavy metal removal

Heavy metal pollution of water is a burning issue of today’s world. Among several strategies involved for heavy metal remediation purpose, biomineralization has shown great potential. Of late, research has been focused on developing effective mineral adsorbents with reduced time and cost consumption. In this present paper, the Biologically-Induced Synthetic Manganese Carbonate Precipitate (BISMCP) was produced based on the biologically-induced mineralization method, employing Sporosarcina pasteurii in aqueous solutions containing urea and MnCl2. The prepared adsorbent was characterized using Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), SEM-energy dispersive X-ray spectroscopy (SEM-EDX), X-ray diffraction (XRD) and BET surface area analyzer. EDX analysis showed the elements in the crystal BISMCP were Mn, C, and O. XRD result of BISMCP determined the crystal structure, which is close to rhodochrosite (MnCO3). Spectral peaks of FTIR at 1641.79 cm−1 confirmed the appearance of CO binding, with strong stretching of CO32− in Amide I. From the six kinds of BISMCP produced, sample MCP-6 has the higher specific surface area by BET analysis at 109.01 m2/g, with pore size at 8.76 nm and higher pore volume at 0.178 cm3/g. These specifications will be suitable as an adsorbent for heavy metal removal by adsorption process. This study presents a preliminary analysis of the possibility of BISMCP for heavy metals adsorption using ICP multi-element standard solution XIII (As, Cr, Cd, Cu, Ni, and Zn). BISMCP formed from 0.1 MnCl2 and 30 ml of bacteria volume (MCP-6) produced a better adsorbent material than others concentrations, with the adsorption efficiency of total As at 98.9%, Cr at 97.0%, Cu at 94.7%, Cd at 88.3%, Zn at 48.6%, and Ni at 29.5%. Future work could be examined its efficiency adsorbing individual heavy metals.

Role of α-Fe2O3 nano-particles in protecting wood from ultraviolet light degradation

Abstract The incorporation of nano-particles into coatings to protect wood against UV light has tremendous potential for improving coating performance. However, the understanding of the mechanisms by which these particles function on wood surfaces remains limited. The distribution and potential chemical interactions between alpha Fe2O3 and wood were studied. The ability of different sizes of Fe2O3 particles to intercept various wavelengths of light was assessed using ultraviolet/visible (UV–vis) spectroscopy using TiO2 and ZnO particles for comparison. All particles intercepted UV light, but α-Fe2O3 also intercepted a portion of the visible spectrum which might help explain its better performance. Scanning electron microscopy/energy dispersive X-ray spectroscopy (SEM-EDS) analysis of α-Fe2O3 nano-particle distribution on different wood orientations of radiata pine (Pinus radiata D. Don) and shining gum (Eucalyptus nitens) showed that iron particles were uniformly distributed on both pine and shining gum, but provided better UV protection to the more permeable radiata pine surfaces. Characterization of chemical interactions between α-Fe2O3 and isolated lignin and cellulose by Fourier Transform Infrared Spectroscopy (FTIR) suggested substantial interactions between these particles and lignin components, but little interaction with cellulose. The results suggest that the role of nano-particles in the UV protection of wood surface is to intercept and disperse the light energy while interacting with the wood.

Mechanical characteristics of fiber-reinforced microcapsule self-healing cementitious composites by orthogonal tests

This study combined the microcapsule self-healing system with fiber reinforced concrete (FRC), and investigated the effects of microcapsule content, mineral admixture type, mineral admixture content, and fiber type on tensile and compressive strength, ductility, and self-healing properties of the fiber-reinforced microcapsule self-healing cementitious composites by the orthogonal test method. For the uniaxial tensile and cubic compression tests, the optimum tensile strength group consists of a 2.2 mass ratio of GGBS, PE fiber, and no microcapsules. The optimum compressive strength group consists of a 2.2 mass ratio of GGBS, hybrid fiber, and no microcapsules. Microcapsule content and fiber type are the main factors affecting tensile properties, and an increase in the microcapsule content will reduce the tensile strength and compressive strength of the matrix. The optimum tensile strain group consists of 10% microcapsule content and a 2.2 mass ratio of GGBS and PE fiber. The results of the energy-based steady-state crack propagation test show that the fiber type is the most critical factor affecting the ductility, and the tensile ductility of the PE fiber group is higher than that of the PVA fiber group. The scanning electron microscopy/energy dispersive X-ray spectrometry (SEM/EDS) diagram proved the healing effect of the fiber-reinforced microcapsule self-healing cementitious composite.

Evaluation of decellularization process for developing osteogenic bovine cancellous bone scaffolds in-vitro.

Current immunological issues in bone grafting regarding the transfer of xenogeneic donor bone cells into the recipient are challenging the industry to produce safer acellular natural matrices for bone regeneration. The aim of this study was to investigate the efficacy of a novel decellularization technique for producing bovine cancellous bone scaffold and compare its physicochemical, mechanical, and biological characteristics with demineralized cancellous bone scaffold in an in-vitro study. Cancellous bone blocks were harvested from a bovine femoral head (18-24 months old) subjected to physical cleansing and chemical defatting, and further processed in two ways. Group I was subjected to demineralization, while Group II underwent decellularization through physical, chemical, and enzymatic treatments. Both were then freeze-dried, and gamma radiated, finally producing a demineralized bovine cancellous bone (DMB) scaffold and decellularized bovine cancellous bone (DCC) scaffold. Both DMB and DCC scaffolds were subjected to histological evaluation, scanning electron microscopy/energy-dispersive X-ray spectroscopy (SEM/EDS), fourier-transform infrared spectroscopy (FTIR), quantification of lipid, collagen, and residual nucleic acid content, and mechanical testing. The osteogenic potential was investigated through the recellularization of scaffolds with human osteoblast cell seeding and examined for cell attachment, proliferation, and mineralization by Alizarin staining and gene expression. DCC produced a complete acellular extracellular matrix (ECM) with the absence of nucleic acid content, wider pores with extensive interconnectivity and partially retaining collagen fibrils. DCC demonstrated a higher cell proliferation rate, upregulation of osteogenic differentiation markers, and substantial mineralized nodules production. Our findings suggest that the decellularization technique produced an acellular DCC scaffold with minimal damage to ECM and possesses osteogenic potential through the mechanisms of osteoconduction, osteoinduction, and osteogenesis in-vitro.

Chemical and morphological characterization by SEM–EDS of PM2.5 collected during winter in Ulaanbaatar, Mongolia

In this study, the morphological and elemental properties of airborne fine particles (PM2.5) collected during winter (15 December 2020–14 January 2021) in Ulaanbaatar, Mongolia, were investigated using scanning electron microscopy (SEM) combined with energy-dispersive X-ray spectrometry (EDS). SEM analysis of the PM2.5 samples revealed that the particle shape distribution on haze days (daily mean PM2.5 concentration of over 100 μg m−3) was irregular (62%), spherical (24.6%), cluster (10.7%), and chain-like (2.7%), while the particle shape on clean days (daily mean PM2.5 concentration of less than 30 μg m−3) was distributed as follows: irregular (56%), cluster (22%), spherical (17.3%), and chain-like (4.7%). The apparent mean particle size on haze days (2.07 μm) was twofold greater than that on clean days (1.13 μm). Based on the EDS spectra, carbonaceous particles were the most abundant (38%), followed by mineral dust (36%), Fe-rich particles (4.7%), N-rich particles (4.7%), calcium sulfate (4%), fly ash (4%) and others (2%) on clean days. On haze days, carbonaceous particles accounted for 86% of the total, and Fe-rich, mineral, transition metal, and calcium sulfate particles accounted for 6.7, 4.7, 1.3 and 0.7%, respectively, indicating that carbonaceous particles were the main contributor on haze days. In particular, the sample filters collected on haze days were predominantly covered with tar/soot-like sticky matter, in contrast to those collected on clean days. Spearman's rank correlation analysis of PM2.5 with inorganic gaseous components as well as meteorological conditions further revealed that high levels of PM2.5 in winter in Ulaanbaatar were significantly associated with SO2 (ρ = 0.95), and CO (ρ = 0.94). These associations indicated that ambient SO2 and CO gases are indicative of haze episodes during the study period, and suggested a strong contribution of solid fuel combustion producing those gases in Ulaanbaatar during winter.

Evaluating organic acids as alternative leaching reagents for rare earth elements recovery from NdFeB magnets

This study proposes an advanced leaching method using organic acids to recover rare earth elements (REEs) from NdFeB permanent magnets from end-of-life computers hard disk drives (HDDs). The end-of-life HDDs were first dismantled in order to recover NdFeB magnets, which were then thermally demagnetized at 350 °C during 30 min before crushing in a ball mill under inert atmosphere. Scanning electron microscopy/energy dispersive X-ray spectroscopy (SEM/EDS) analyses performed on the NdFeB magnets show the heterogeneous structure containing the major matric phase Nd2Fe14B and the rich-REEs phase containing Nd and Pr oxides. Additionally, X-ray diffraction (XRD) and Mössbauer spectroscopy (MS) analyses on the ground NdFeB magnet show that grinding NdFeB magnets under inert atmosphere helps to minimize its oxidation. Chemical analysis shows that the composition of the ground sample is Nd: 22.8 wt%, Pr: 3.3 wt%, Dy: 1.2 wt%, Fe: 62.6 wt%, Co: 1.5 wt%, B: 0.9 wt%, Ni: 0.6 wt%. Diagrams of speciation and equilibrium phases (Eh vs. pH) were calculated to determine the predominance of the formed species in the REEs–organic acids systems. The influence of the organic acid type (acetic acid, formic acid, citric acid and tartaric acid), the acid concentration (10 vol%, up to saturation), and the solid/liquid (S/L) ratio (0.5%–10%) on NdFeB magnets leaching was investigated employing an optimal experimental design conceived by the statistical software JMP. Acetic acid (CH₃COOH) shows the highest leaching performance of REEs, allowing leaching yields over 90% for Nd, Dy and Pr in the acid concentration (mol/L) range of 1.6 – 10 and the S/L ratio (%) range of 0.5 – 5 using a temperature of 60 °C. The results presented in this investigation suggest that REEs can be recovered from magnets of end-of-life HDDs using an eco-friendly method assisted by organic acids.

Decoration of 1,3 oxazole modified g- C3N4 by Bio-synthesized Ag nanoparticle for the photodegradation of pharmaceutical effluent: Clotrimazole

The current work demonstrates the fabrication of Ag nanoparticle (Ag nps) loaded oxazole modified g- C3N4(COA) photo catalysts. A novel green method was opted to synthesize silver nanoparticles using seed extract of Nigella sativa. The photo catalyst was comprehensively characterized by Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), Scanning electron microscopy/energy dispersive X-ray spectroscopy (SEM/EDS), High-resolution transmission electron microscopy (HR-TEM) and X-ray photoelectron spectroscopy (XPS). The optical activities were analysed by double beam UV–Vis and photoluminescence. The catalytic potential of synthesized COA have been tested for degradation of Clotrimazole (CTZ) pharmaceutical effluent as model pollutant. The photo degradation results have shown that about 94.5 % of CTZ get degraded over the duration of 120 min. To explore the real scale application, the effect of catalysts dosage and pH have been studied. The major active radical species responsible for the degradation have been identified by radical scavenging experiments.

Keratin coated titanium as an aid to osseointegration: Physicochemical and mechanical properties

Wool-extracted keratin has been shown to promote bone formation in vivo and may therefore be a potential novel bioactive coating material for osseous implants. This study examined the physicochemical and mechanical properties of keratin-coated titanium, to assess its potential for use in bone-implant applications. Keratin was covalently coupled to silane and glutaraldehyde treated titanium by either (a) molecular grafting or (b), solvent casting. The coated titanium surfaces physicochemical properties including contact angle, roughness, degradation, and swelling characteristics, were subsequently characterized using attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR), scanning electron microscopy-energy dispersive X-ray spectroscopy (SEM-EDS), X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD). Mechanical properties including the coating adhesion strength and tensile strength were also examined. ATR-FTIR, XPS, XRD, and SEM-EDS all confirmed the presence of keratin on both coated titanium surfaces. SEM imaging showed that solvent casting produced a thick coating which completely covered the titanium surface, while molecular grafting produced a discontinuous thinner coating. The surface roughness increased similarly using either coating methodology while molecular grafting only, increased surface wettability. Both keratin-modified titanium surfaces were stable in solution over 28 days demonstrating suitability for in vivo applications, while the solvent cast titanium also showed good adhesion and tensile bond strength of the coated keratin. These results show a stable keratin coating on the titanium surface was successfully obtained which has both the physiochemical and mechanical properties required for potential dental and or orthopaedic implant applications.

In Vitro Degradation of Mg-Doped ZrO2 Bioceramics at the Interface with Xerostom® Saliva Substitute Gel

Zirconia-based bioceramics, one of the most important materials used for dental applications, have been intensively studied in recent years due to their excellent mechanical resistance and chemical inertness in the mouth. In this work, the structural, morphological and dissolution properties of the Zr1-xMgxO2 (x = 0.05, 0.1, 0.15, 0.2, 0.25, and 0.3) system, prepared by the conventional ceramic method, were evaluated before and after immersion in saliva substitute gel (Xerostom®, Biocosmetics Laboratories, Madrid, Spain), one of the most common topical dry mouth products used in dentistry. The X-ray powder diffraction (XRPD), Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy/energy-dispersive X-ray spectroscopy (SEM/EDS) techniques were employed to investigate the phase transformations and morphology of the ceramics during the degradation process in Xerostom®. In vitro analyses showed overall good stability in the Xerostom® environment, except for the x = 0.05 composition, where significant t- to m-ZrO2 transformation occurred. In addition, the strong interconnection of the grains was maintained after immersion, which could allow a high mechanical strength of the ceramics to be obtained.

Electromagnetic Interference Shielding Effectiveness of Direct-Grown-Carbon Nanotubes/Carbon and Glass Fiber-Reinforced Epoxy Matrix Composites.

In this study, carbon nanotubes (CNTs) were grown under the same conditions as those of carbon fibers and glass fibers, and a comparative analysis was performed to confirm the potential of glass fibers with grown CNTs as electromagnetic interference (EMI) shielding materials. The CNTs were grown directly on the two fiber surfaces by a chemical vapor deposition process, with the aid of Ni particles loaded on them via a Ni-P plating process followed by heat treatment. The morphology and structural characteristics of the carbon and glass fibers with grown CNTs were analyzed using scanning electron microscopy-energy dispersive X-ray spectroscopy (SEM-EDS), X-ray diffraction (XRD), and X-ray photoelectron spectrometry (XPS), and the EMI shielding efficiency (EMI SE) of the directly grown CNT/carbon and glass fiber-reinforced epoxy matrix composites was determined using a vector-network analyzer. As the plating time increased, a plating layer serving as a catalyst formed on the fiber surface, confirming the growth of numerous nanowire-shaped CNTs. The average EMI SET values of the carbon fiber-reinforced plastic (CFRP) and glass fiber-reinforced plastic (GFRP) with grown CNTs maximized at approximately 81 and 40 dB, respectively. Carbon fibers with grown CNTs exhibited a significantly higher EMI SET value than the glass fiber-based sample, but the latter showed a higher EMI SET increase rate. This indicates that low-cost, high-quality EMI-shielding materials can be developed through the growth of CNTs on the surface of glass fibers.

Fabrication of aluminum titanate–glass composites with controlled thermal expansion and improved mechanical strength

Aluminum titanate–glass sintered composites with a controlled thermal expansion coefficient were successfully prepared by the solid-state reaction of Al2O3, TiO2, and soda-lime glass powders. The thermal expansion of the specimens monotonically increased from negative to positive when the glass addition was increased from 0 to 30 wt%, indicating that a zero-thermal-expansion material could be obtained at a glass addition of 5–7 wt%. Chemical reaction between glass and Al2TiO5 was not observed during sintering, and the glassy state of the raw soda-lime glass was maintained. The scanning electron microscopy–energy-dispersive X-ray spectroscopy results indicate that the glassy phase penetrates the grain boundaries of the sintered composites with a glass addition of 5 wt%, thereby increasing the thermal expansion coefficient and apparent density. For the composites with a glass content of >5 wt%, a glassy phase that possibly forms outside the grain boundary could increase the thermal expansion coefficient and decrease the density. The glassy phase at the grain boundary also effectively improved the mechanical bending strength.

Micro-Raman spectroscopy analysis of dentin remineralization using eggshell derived nanohydroxyapatite combined with phytosphingosine

The aim of this study was to assess the remineralization efficacy of chicken eggshell–derived nano-hydroxyapatite (CEnHAp) combined with phytosphingosine (PHS) on artificially induced dentinal lesions. PHS was commercially procured whereas CEnHAp was synthesized using microwave-irradiation method and characterized using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), high-resolution scanning electron microscopy–energy-dispersive X-ray spectroscopy (HRSEM-EDX), and transmission electron microscopy (TEM). A total of 75 pre-demineralized coronal dentin specimens were randomly treated with one of the following test agents (n = 15 each): artificial saliva (AS), casein phosphopeptide-amorphous calcium phosphate (CPP-ACP), CEnHAp, PHS, and CEnHAp-PHS under pH cycling for 7, 14, and 28 days. Vickers microhardness indenter, HRSEM-EDX, and micro-Raman spectroscopy methods were used to assess the mineral changes in the treated dentin samples. Data were submitted to Kruskal–Wallis and Friedman's two-way analyses of variance (p < 0.05). HRSEM and TEM analysis depicted irregular spherical structure of the prepared CEnHAp with a particle size of 20–50 nm. The EDX analysis confirmed the presence of Ca, P, Na and Mg ions. The XRD pattern showed the characteristic crystalline peaks for hydroxyapatite and calcium carbonate that are present in the prepared CEnHAp. Dentin treated with CEnHAp-PHS revealed highest microhardness values along with complete tubular occlusion compared to other groups at all test time intervals (p < 0.05). Specimens treated with CEnHAp showed increased remineralization than those treated with CPP-ACP followed by PHS and AS groups. The intensity of mineral peaks, as observed in the EDX and micro-Raman spectra, confirmed these findings. Further, the molecular conformation of the collagen's polypeptide chains, and amide-I and CH2 peaks attained peak intensities in dentin treated with CEnHAp–PHS and PHS whereas other groups revealed poor stability of collagen bands. Microhardness, surface topography, and micro-Raman spectroscopy analyses revealed that dentin treated with CEnHAp–PHS have an improved collagen structure and stability as well as highest mineralization and crystallinity.

Divergent gunshot residues and characterization of the memory effect in a .22 caliber revolver and pistol

BackgroundThe forms and compositions of primer gunshot residue (GSR) in shooting cases have been routinely analyzed in many crime labs by scanning electron microscope/energy-dispersive X-ray spectroscopy (SEM/EDS). Gunshot residue studies over the last 30 years have identified a contribution by residual GSR from surfaces within the firearm to GSR (the “memory effect”). In this study, we first focus on the GSR compositional differences between target, bore, and cylinder gap for a .22 caliber revolver which has received little attention in the literature. Secondly, we examine the behavior of elements involved in the residual contribution to GSR for a .22 caliber pistol.ResultsThe compositions of target, bore, and cylinder gap GSRs from a .22 caliber revolver were determined for 11 discharge series. Breech GSR compositions from a .22 caliber pistol changed in sequential discharges revealing behavior of individual primer and bullet elements. The target GSR forms from some .22 caliber ammunitions were not spherical.ConclusionsFor the revolver, GSR compositions from the target, bore, and cylinder gap are divergent. Analysis of the pistol’s breech GSRs indicated mixing with the previously deposited GSRs resulting in a sequential contribution or loss of elements and redeposition of the new composition. Aluminum did not contribute to the residual GSR. The GSR composition of a discharge and its contribution to residual GSR on the internal parts of the firearm represents a complex process which likely involves a number of variables including, but not restricted to firearm design, primer composition, pressure and temperature of the discharge gas, and bullet surface composition.

Brass metallurgy in Urartu: Recent evidence from eastern Anatolia

Traditionally, the beginning of substantial and deliberate brass production through the cementation process has been placed to the Early Roman period. Sporadic early finds have accordingly been considered to be the result of various experimentations by eastern Mediterranean metallurgists at least since the Late Bronze Age. Several Anatolian finds, dated to the early first millennium BC, that were made from zinc rich alloys have been interpreted within this framework. In ancient Urartu, however, the mastery and application of advanced metal technologies of both casting and working of copper-alloys as well as blacksmithing are well documented. This study aims to provide a further understanding of this phenomenon by shedding light on the development of zinc metallurgy in eastern Anatolia based on recent finds unearthed during the rescue excavations at Murat Tepe and Murat Höyük in the Murat River basin in modern eastern Türkiye. In both cases the metal assemblages from stratified contexts were analysed by the means of multiple archaeometallurgical methods. The results from portable XRF (pXRF), metallography, micro-hardness, scanning electron microscopy-energy dispersive X-ray spectrometry (SEM-EDS) and Raman spectroscopy analyses have showed that zinc was intentionally used as an alloy additive in order to fabricate brass. Moreover, in one case, the chemical composition consisting of zinc (Zn), tin (Sn) and copper (Cu) was detected, which indicates different alloying practices for the production of different types of objects. These new observations raise further questions about the deliberate production and manufacturing of brass prior to the wide spread of this metal technology in the Roman period.

The Effect of Adding Corn Cob Ash to The Physical and Mechanical Properties of Mortar

The research was carried out about the effect of adding corn cob ash on mortar's physical and mechanical properties. Mortar was molded with three compositions, i.e., portland cement, corn cob ash, and corn husk fiber. Corn cob ash was burned at a temperature of 700 for 2 hours. Corn husk fiber was mechanically sliced up to 0.8 mm in size. Then, mortar molding and maintenance were processed for 28 days. The mortars that had reached the age of 28 days were tested according to the Indonesian National Standard (SNI), including physical properties (density) and mechanical properties (compressive strength, flexural strength, splitting tensile strength). Characterization of microstructure, morphology, and composition of all elements on the mortar's surface was processed using Scanning Electron Microscopy-Energy Dispersive X-ray Spectroscopy (SEM-EDS). The research results show the influence of adding corn cob ash on mortar's physical and mechanical properties. The mortar with the most optimum physical and mechanical properties has a composition of 82:6:12. The characterization results using SEM-EDS show that the surface of this composition sample is better than other samples. The most dominant elements in the mortar are elements of Ca and Si, which function as mortar binders and hardeners.

Investigation of Cu Adsorption and Migration with Spectral Induced Polarization in Activated Carbon.

In this paper, the adsorption process of copper ions on activated carbon (AC) was simulated in a column test. It was deduced that it is consistent with the pseudo-second-order model. Cation exchange was observed to be the major mechanism of Cu-AC interactions through scanning electron microscopy-energy dispersive X-ray spectroscopy (SEM-EDS), X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FTIR) measurements. Adsorption isotherms were fitted well using the Freundlich model. Adsorption thermodynamics at 298, 308, 318 K demonstrated that the adsorption process is spontaneous and endothermic. Spectral induced polarization (SIP) technique was used to monitor the adsorption process, and the double Cole-Cole model was used to analyze the SIP results. The normalized chargeability was proportional to the adsorbed copper content. Two measured relaxation times from the SIP testing were converted into the average pore sizes of 2, 0.8, 0.6, 100-110, 80-90, and 53-60 µm by the Schwartz equation, which are consistent with the measured pore sizes from both mercury intrusion porosimetry and scanning electron microscopy (SEM). The reduction in the pore sizes by SIP during the flow-through tests suggested that the adsorbed Cu2+ gradually migrated into small pores as with continued permeation of the influent. These results showcased the feasibility of using SIP technique in engineering practice involving the monitoring of copper contamination in land near a mine waste dump or in adjacent permeable reactive barriers.

Self-repairing of shrinkage crack in mortar containing microencapsulated bacterial spores

The purpose of this research work was to evaluate the efficacy of microbially induced calcite precipitation (MICP) method in shrinkage crack repairing. Portland cement was combined with sand, bacterial spores, water, and nutrients to prepare self-healing composites. The microencapsulated bacterial spores were employed as an additive substance at ratios of 0%, 0.5%, and 1% by weight of cement. Specimens were kept in a climate-controlled room after casting to induce shrinkage crack. Crystalline phases formed in the specimen were identified using the X-ray diffraction (XRD) technique. The scanning electron microscopy/energy dispersive X-ray spectrometry (SEM/EDS) method was used to investigate the morphology of precipitated calcite (CaCO3) crystals. Additionally, the specimen's permeability and compressive strength were also determined. When the bacterial spores were added to produce MICP procedure, the results demonstrated that it was successful in healing the shrinkage cracking. Within three days, the specimen with 1% spores could completely seal the shrinkage crack. According to the XRD patterns, the CaCO3 crystals appeared to promote the production of the calcite phase. Based on SEM/EDS investigation, the MICP process leads to concentrations of calcite crystal in certain regions, especially at the top surface of the crack. The 28-day compressive strength, on the other hand, decreased, owing to the addition of nutrients.