X-ray Diffraction Research Articles

Preparation and Tribological Performance of the Ag/BN Nanocomposite as Additives for Lithium-Based Grease

This study synthesized a nanocomposite composed of silver nanoparticles and boron nitride (Ag/BN nanocomposite) by depositing Ag nanoparticles on BN surfaces. The chemical composition, structure, micromorphology, and tribological properties of the Ag/BN nanocomposite were investigated using transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), Raman spectroscopy, and a high-speed reciprocating tribometer. Under a 10 N load, 30 min test duration, 50 mm/s sliding speed, and 2 wt% additive concentration, lithium-based grease (LBG) containing Ag/BN nanocomposite exhibited the lowest average friction coefficient of 0.33 and a wear rate of 1.08 × 10−14 m3/(N × m), representing reductions of 35.2% and 41.6%, respectively, compared to pure LBG. A further analysis of the friction mechanism was conducted using 3D laser scanning microscopy, scanning electron microscopy (SEM), and XPS. The results indicate that the Ag/BN nanocomposite effectively reduced friction and wear on the friction pair surfaces through repair mechanisms, the formation of lubricating films, and micro-bearing effects.

Highly Luminescent Nitrogen Doped Carbon Quantum Dots for Mercury Ion Sensing with Antibacterial Activity.

Nitrogen doped Carbon Quantum Dots (NCQDs) have been synthesized using most economical and easiest hydrothermal process. Here, N-phenyl orthophenylenediamine and citric acid were utilised as a source of nitrogen and carbon for the preparation of NCQDs. The synthesized NCQDs were characterized using experimental techniques like UV - Vis absorption, FT-IR, transmission electron microscopy (TEM), X-ray Diffraction (XRD), EDX, dynamic light scattering (DLS), fluorimeter and time resolved fluorescence spectroscopy. Measured quantum yield of the NCQDs was ~ 50.5%. TEM image represented that the NCQDs were quasi-spherical shaped with average size of 3.5nm. This nitrogen doped carbon quantum dots have been used to study their bactericidal activity against representative Gram-negative (E. coli and P. aeruginosa) and Gram-positive (B. subtilis and S. aureus) bacterial strains using the agar well diffusion method. Results demonstrated that synthesized Nitrogen doped carbon quantum dots have been found to exhibit maximum antibacterial activity against S. aureus with good inhibitory effect with inhibition range from 2mg mL- 1 to 3mg mL- 1. These Nitrogen doped carbon quantum dots have also been used as fluorescence probe for sensitive and selective detection of mercury. The emission intensity of carbon quantum dots has drastically quenched by Hg2+ ion. Observed limit of detection (LOD) was found to be 4.98 nM, much below than the approved limit prescribed by Environmental Protection Agency. Hence the synthesized NCQDs play an important role in monitoring the antibacterial effect as well as water quality.

Effectively eliminating lead and cadmium from industrial wastewater using a biowaste-based sorbent

Toxic heavy metals, such as Pb(II) and Cd(II), pose serious environmental and health risks, stressing the urgent demand for innovative and sustainable techniques to reduce their adverse effects. This study investigates the use of sugar beet biowaste as an eco-friendly biosorbent for the removal of Pb(II) and Cd(II) from aqueous solutions, in both laboratory and industrial effluents. Characterization through scanning electron microscopy, X-ray diffraction, thermogravimetric analysis, Fourier-transform infrared spectroscopy, and energy-dispersive X-ray spectroscopy revealed the formation of stable hydrocerussite and otavite, confirming chemisorption. Approximately 95% of the employed biowaste is composed of calcium (Ca), carbon (C), and oxygen (O). The zeta potential was measured at − 17.5 mV with a point of zero charge at pH 8.0, and the total surface area of the biosorbent was approximately 7.72 m2 g−1, with a Langmuir surface area of 11.563 m2 g−1 and a pore volume of 0.028 cm3 g−1. Various parameters, such as the metal concentration, biosorbent dosage, pH, temperature, and contact time, were optimized, achieving maximum removal of Pb(II) and Cd(II) within 60 min at pH 12 and 328 K. Sorption followed a pseudo-second-order kinetic model (R2 = 0.99) and the Freundlich isotherm (R2 = 0.98), with high sorption capacities of 466.5 mg g−1 for Pb(II) and 505.6 mg g−1 for Cd(II). Thermodynamic analysis indicated that the sorption process is spontaneous, thermodynamically favorable, and endothermic. The biowaste effectively removed heavy metals and demonstrated removal efficiencies exceeding 85% for most heavy metals in industrial effluent samples from Alexandria and Ain Sokhna. Sorption capacity ratio values close to 1 indicate effective Pb(II) and Cd(II) uptake with minimal interference, even in the presence of methylene blue dye. Comparative analysis revealed that the untreated biosorbent was more efficient than typical biosorbents, and an economic cost evaluation revealed that processing the biosorbent costs 1.05 USD/kg, highlighting its potential as a sustainable and economically viable option for industrial effluent treatment and supporting broader environmental goals.

Structure and Corrosion Resistance of Fe40Al5Cr0.2TiB Alloy After Casting and After Homogenization Annealing

This article shows the results of research conducted on the corrosion resistance of the FeAl (Fe40Al5Cr0.2TiB) alloy in two variants: the alloy after casting and after homogenization annealing (1000 °C, 93 h). Analysis of the microstructure of these alloys was conducted on the light microscope, and the phase composition was determined by X-ray diffraction. Resistance to electrochemical corrosion was tested in a 5% NaCl solution using the potentiodynamic polarization technique and electrochemical impedance spectroscopy. The surface of alloys after corrosion tests was examined by scanning electron microscopy. Chemical composition tests were conducted using an energy-dispersive X-ray spectrometer. The structure analysis was made with an electron backscatter diffraction detector. Based on the studies, it was found that the corrosion resistance of the FeAl alloy after homogenization annealing was higher than that of the FeAl alloy after casting. This alloy showed a more non-homogeneous and coarse-grained microstructure compared to the alloy after homogenization annealing. The investigation of the surface condition of FeAl alloys after corrosion tests showed the presence of pits, particularly in the case of the alloy after casting.

Electro-Oxidation of Glycerol on Core–Shell M@Pt/C (M = Co, Ni, Sn) Catalysts in Alkaline Medium

This study explores the development of core–shell electrocatalysts for efficient glycerol oxidation in alkaline media. Carbon-supported M@Pt/C (M = Co, Ni, Sn) catalysts with a 1:1 atomic ratio of metal (M) to platinum (Pt) were synthesized using a facile sodium borohydride reduction method. The analysis confirmed the formation of the desired core–shell structure, with Pt dominating the surface as evidenced by energy-dispersive X-ray spectroscopy (EDS). X-ray diffraction (XRD) revealed the presence of a face-centered cubic (fcc) Pt structure for Co@Pt/C and Ni@Pt/C. Interestingly, Sn@Pt/C displayed a PtSn alloy formation indicated by shifted Pt peaks and the presence of minor Sn oxide peaks. Notably, no diffraction peaks were observed for the core metals, suggesting their amorphous nature. Electrocatalytic evaluation through cyclic voltammetry (CV) revealed superior glycerol oxidation activity for Co@Pt/C compared to all other catalysts. The maximum current density followed the order Co@Pt/C > Ni@Pt/C > Sn@Pt/C > Pt/C. This highlights the effectiveness of the core–shell design in enhancing activity. Furthermore, Sn@Pt/C displayed remarkable poisoning tolerance attributed to a combined effect: a bifunctional mechanism driven by Sn oxides and an electronic effect within the PtSn alloy. These findings demonstrate the significant potential of core–shell M@Pt/C structures for designing highly active and poisoning-resistant electrocatalysts for glycerol oxidation. The presented approach paves the way for further development of optimized catalysts with enhanced performance and stability aiming at future applications in direct glycerol fuel cells.

Extraction, Characterization and Antibacterial Activity of Chitosan from Mud Crab Scylla serrata

The shellfish waste accumulated on a huge scale at seashores and in the seafood industry and very low quantities were used to extract chitosan. In this study, chitosan was extracted from the mud crab Scylla serrata shell using conventional chemical methods. The extracted chitosan and commercial chitosan were verified through Field Emission Scanning Electron Microscopy (FE-SEM), Attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR), X-ray diffraction (XRD), and an elemental analyzer. ATR-FTIR spectrum confirmed the presence of characteristics compounds of chitosan and XRD patterns exhibited crystallinity of chitosan having centered peaks at 10º and 20º in 2θ. Moreover, 46.24% of the degree of deacetylation was obtained for the extracted chitosan altogether enhancing the quality of extracted chitosan. In addition to this, the extracted chitosan was tested for its antibacterial activity against two Gram-negative (E. coli and Pseudomonas) and two Gram-positive bacteria (Staphylococcus and Bacillus) in vitro. The antimicrobial activity of extracted chitosan was evident with the greater zone of inhibition against E. coli (26±0.32mm) and the least against Staphylococcus (18mm). Hence the present study gives insight into the biological properties of extracted chitosan from Scylla serrata thereby paving the way for its further use in biomedical science and microbiology.

Effective removal of heavy metal ions (Pb, Cu, and Cd) from contaminated water by limestone mine wastes

Limestone mining waste and its derived CaO were checked as an adsorbents of pb2+, Cu2+, and Cd2+ ions from water solution. The characterization of Limestone and calcined limestone was studied by using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), Scanning Electron Microscope (SEM), and Surface area measurements (BET). The optimum conditions of sorbent dosage, pH, initial concentration, and contact time factors were investigated for pristine limestone and calcined limestone absorbents. The results indicate that the optimum initial concentrations of (Ci) were 1200, 500, and 300 ppm for Pb, Cu, and Cd, respectively, using calcined limestone adsorbent, while using the pristine limestone adsorbent, the corresponding optimum initial concentrations were 700, 110, and 50 ppm. In the ternary system sorption, the results indicated that the selectivity sequence of the studied metals by limestone can be expressed as Pb2+ > Cd2+ > Cu2+, while calcined limestone exhibits a higher selectivity for Pb2+ compared to Cu2+ and Cd2+. Hence, various adsorption isotherm and kinetic models were examined to explore different patterns and behaviors of adsorption. So, the results indicate that calcined limestone has great potential for eliminating cationic heavy metal species from industrial water solutions.

Microwave-assisted extraction of dandelion root polysaccharides: Extraction process optimization, purification, structural characterization, and analysis of antioxidant activity.

This study aimed to establish a microwave-assisted method (MAE) for the efficient extraction of polysaccharides from dandelion roots. This study investigated the molecular structure and bioactivity of the polysaccharides from dandelion roots. Extraction conditions were optimized using response surface methodology (RSM). The microwave extraction conditions were set to an extraction time of 42 min, an extraction temperature of 80 °C, and a solid-liquid ratio (g/mL) of 1:33. Under the optimized conditions, the highest dandelion root polysaccharides (DRP) yield was achieved (24.85 ± 0.457 %). Water-pure DRP (DRPw) and NaCl-pure DRP (DRPs) were purified by activated carbon decolorization and DEAE fiber column chromatography. The molecular weights of DRPw and DRPs were 8653 Da and 5930 Da, respectively. The Fourier transform infrared spectroscopy (FTIR) and nuclear magnetic resonance (NMR) analyses confirmed the existence of α- and β-pyranose in DRPw and DRPs. The results of X-ray diffraction (XRD) and scanning electron microscopy (SEM) showed that DRPw and DRPs were semi-crystalline substances with irregular shapes and rough surfaces. Bioactivity assays revealed the good antioxidant activities of DRPw and DRPs. The present study provides useful information about DRP as natural antioxidants for the benefit of food.

Neuroprotective Indole Alkaloids from the Soil-Derived Fungus Trichocladium sp. XZ8.

A chemical investigation of the soil-derived fungus Trichocladium sp. XZ8 led to the isolation of five new indole alkaloids, trichindoles A-E (1-5), with diverse architectures, along with seven known analogues (6-12). Their structures were elucidated by extensive spectroscopic data analysis, and their absolute configurations were determined by single-crystal X-ray diffraction and modified Mosher's method. Compound 1 is a polyketide-alkaloid hybrid incorporating a rare succinimide motif, and compound 2 represents the first example of a dimeric isopentenyl indole-containing alkaloid bridged by a propane-1,2-diol moiety. Compounds 1, 4, 8, 11, and 12 showed significant neuroprotective effects against RSL3-induced ferroptosis in PC12 cells at 10 μM. Moreover, 1 and 4 might ameliorate RSL3-induced ferroptosis through the regulation of the SLC7A11 pathway and ferritinophagy, suggesting their potential as promising lead compounds for the treatment of neurodegenerative diseases.

Synthesis and structural insights of bis(2-methoxy-6-{[(2-methylpropyl)imino]methyl}phenolato) nickel (II) complex through DFT and docking investigations

Nickel complexes are a potential candidate for antibacterial and antifungal activity. A new Ni (II) complex, bis(2-methoxy-6-{[(2-methylpropyl)imino]methyl}phenolato)nickel (II) (2), was synthesised by reacting, bis(3-methoxy-salicylaldehyde)nickel (II) (1) with isobutylamine. It was characterised by single crystal X-ray diffraction (ScXRD), UV-Vis, NMR, IR, mass spectrometry, and thermogravimetry (TG) to study its structure and physico-chemical properties. The ScXRD showed a square planar geometry, and monoclinic crystal system with a space group P21/n. The TG analysis revealed its thermal durability pre and post-melting up to 225 oC with a weight loss of only 2%. The optimized molecular structure, energy gap between HOMO and LUMO, and intermolecular interactions were studied by computational methods. The microbial activity evaluation showed significant anti-bacterial activity against E. coli and S. aureus when the concentration exceeded 40 µg/mL, and a prominent anti-fungal activity over C. albicans and C. tropicalis above 30 µg/mL. The values of minimum inhibitory concentration (MIC) for bacteria (MIB) and fungi (MIF) implied its potential to inhibit the growth of microbes. Docking studies revealed that the molecule binds well with proteins such as PDB: 2W9H for Dihydrofolate Reductase of S.aureus as shown by its binding energy of -8.62 kcal.mol− 1.

Impact of a Segmented-Scan Strategy on Residual Stress and Fit Accuracy of Dental Prostheses Fabricated via Laser-Beam Powder-Bed Fusion

The laser-beam powder-bed fusion (PBF-LB) method enables the semi-automatic fabrication of complex three-dimensional structures, making it useful for dental prostheses. However, residual stress during fabrication can cause deformation. Herein, we applied the segmented-scan strategy to three-unit fixed dental prostheses (FDPs) and evaluated its effects on residual stress and fit accuracy compared to conventional methods. Three-unit FDPs consisting of two abutments and a pontic were fabricated using a PBF-LB machine with Co-Cr-Mo powder. In the segmented-scan group, pontics and abutments were scanned separately to shorten the scan vector. Fit accuracy was assessed by measuring the gap between the abutment and the FDPs. Residual stress was measured in the X and Y directions at three points using X-ray diffraction, while CT scans were used to count internal microstructures. The residual stress was lower in the X-direction in the segmented-scan group (24.61–217.17 MPa, respectively) than in the control group (187.70–293.71 MPa, respectively). However, no significant differences in fit accuracy were observed (p < 0.05). The segmented-scan strategy reduced residual stress in the X-direction but did not improve the fit accuracy. Applying this strategy to dental prosthetic devices can shorten the scan vector and reduce residual stress.

Investigation of biological activities of silver nanoparticles synthesis from the root extract of endemic Onosma mutabilis (O. mutabilis) Plant

Plant-mediated silver nanoparticles (AgNPs) synthesis appears to be reliable and environmentally friendly, requiring less energy, and cost. Various components present in its natural products can function as strong reducing and capping substrates, ensuring the stability of the resulting NPs. This study synthesized AgNPs with root extracts of O. mutabilis. The effect of many different synthesis parameters (such as silver ion concentration, temperature and reaction pH) of the obtained root extract on the synthesis of AgNPs was also examined. Furthermore, AgNPs were characterized using UV-Vis spectroscopy, Fourier-transformed infrared spectroscopy (FT-IR), X-ray diffraction (XRD), scanning electron microscopy (SEM), particle size measurement (Malvern Mastersizer) and energy dispersive X-ray analysis (EDX). The surface plasmon resonance band features of AgNPs were determined in the ultraviolet-visible absorbance spectrum at 410 nm. Total phenolic compound (TPC) determination was analyzed using the Folin-Ciocalteu method, and TPC in AgNPs extracts was determined as 295 ± 0.02 mg GAEs/gr extract. The antioxidant activity of the AgNPs was examined using the 1,1‐diphenyl‐2‐picrylhydrazyl (DPPH) free radical scavenging activity method. The synthesized AgNPs exhibited strong antioxidant activity. The antidiabetic activity was determined by measuring alpha-amylase inhibition by spectrophotometric method. α-amylase inhibition values were determined to be highest at 31%. The study was further elaborated for determining AgNPs antibacterial using MIC. The biosynthesized AgNPs showed effective antibacterial activity against the Acinetobacter baumannii (A.baumannii) bacteria.Suggests that green biosynthesized AgNPs can constitute an effective antioxidant, antidiabetic and antibacterial agent.

Mechanochemical Synthesis of Phase-Pure CsCu2I3 and Cs3Cu2I5 Phosphors Regulated by Polar Solvents and Their Application in Tunable Chromaticity LEDs.

Lead halide perovskites have garnered interest in light-emitting diode (LED) applications due to their strong emission and tunable properties. However, conventional synthesis methods involve energy-intensive thermal processes and hazardous organic solvents, raising environmental concerns. In this study, we report a simple and eco-friendly mechanochemical approach that produces phase-pure blue-emitting Cs3Cu2I5 (emission at 440 nm) and yellow-emitting CsCu2I3 (emission at 570 nm) phosphors through polarity modulation and control of grinding duration. Our comprehensive analysis of the phase transitions during mechanochemical synthesis reveals that pure Cs3Cu2I5 was synthesized from a 3:2 precursor molar ratio in ethanol for 30 min, while pure CsCu2I3 was obtained from a 1:2 precursor molar ratio in an aqueous solution for 7.5 min. Moreover, Raman spectroscopy, X-ray diffraction, and energy-dispersive X-ray spectroscopy analyses confirmed that phase-pure phosphors were achieved through these methods. Finally, we fabricated a series of color-adjustable LEDs by mixing Cs3Cu2I5 and CsCu2I3 phosphors in different proportions. This demonstrates the potential of our mechanochemical synthesis for the efficient, large-scale production of next-generation lighting materials with tunable emission.

Characterization of Asaba Clay for Production of Porcelain Insulator

Abstract: The study highlights the potential of Asaba clay for producing high-quality ceramic wares by examining the physicochemical characteristics of clay mineral using advanced analytical techniques such as X-ray fluorescence (XRF), X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR), and atomic absorption spectrophotometry (AAS). Results obtained reveal that the sample was kaolinite with SiO2 (43.63%), Al2O3 (16.65%), and Fe2O3 (4.87%) as the most predominant elements. The identified minerals include Quartz (SiO2), Orthoclase (KAlSi2O3), Kaolinite (Al2O3•2SiO2•2H2O), and Albite (NaAlSi2O3). Wavenumbers ranges from 3697.51913 - 685.83016, while the high intensities of the hydroxyl-related peaks at 3421.70 cm⁻¹, 3622.97 cm⁻¹, and 3697.52 cm⁻¹ suggest that Asaba clay has properties similar to kaolinitic. Elemental composition indicates that the elements (Co, Cr, Cu, Fe, Mn, Ni, Pb, Cd, Zn and Ca) are in acceptable concentration levels. The study therefore revealed that the clay from Asaba has kaolinite characteristics, is environmentally safe and is therefore suitable for porcelain insulator production.

Mineralogical analysis of plutonic and volcanic rocks at selected slope sections of the Kuala Lumpur-Karak Highway

The Kuala Lumpur-Karak Highway (KL-KH) is a key route connecting Kuala Lumpur to the East Coast states of Peninsular Malaysia. It passes through three distinct geological formations: the Kuala Lumpur Granite, Genting Sempah Complex, and Bentong Raub Suture Zone. These formations feature unique rock mineral compositions and microstructures that influence the strength and behavior of rock masses. This study used X-ray Diffraction (XRD) and Scanning Electron Microscopy (SEM) to analyze the mineralogical properties of plutonic and volcanic rock samples from the highway. The plutonic sample from KM29 (GKM29) consists of quartz, muscovite, and albite, while the volcanic sample from KM93 (LKM93) is rhyolite, containing quartz, albite, muscovite, and biotite. While both samples share similar minerals, they differ in texture, mineral proportions, and carbon content. The GKM29 sample has a more granular texture, while the LKM93 sample is finer. These differences in mineral composition and texture affect the mechanical properties of the rocks, including strength and durability, which are crucial for slope stability. Understanding these variations is essential for assessing slope stability and potential geological hazards along the highway. This study emphasizes the importance of early geological assessments for effective slope management and road safety, enabling better planning and maintenance strategies.

Fabrication of polymethyl methacrylate composite films with silanized SiC nanoparticles

The properties of polymeric composites have often been altered with the incorporation of fillers. In this study, the poly(methyl methacrylate) (PMMA) was filled with silicon carbide nano-particles (SiC). The PMMA/SiC composite films were prepared through solution casting by using acetone as solvent. The different loading of SiC ranging from 0.25 wt% to 1.00 wt% were incorporated into the PMMA matrix. The effect of SiC loading and silane coupling agent on PMMA/SiC composite films in terms of mechanical, physical, and morphological properties was investigated. It was found that the increasing SiC loading and the silane treatment had increased the tensile strength and Young’s modulus but reduced the elongation at the break of PMMA/SiC composite films. At 0.75 wt% of silanized SiC, the tensile strength of the composite films was found to increase by 25 % from 30 to 37.5 MPa as compared to the virgin PMMA. Besides, the hardness of composite films was also increased with SiC loading and silane treatment. The presence of 1.00 wt% silanized SiC had increased 21.7% the hardness of the virgin PMMA, resulting in the increase of Shore A value from 69 to 84. By using silane treatment, better filler-matrix interaction was established as smoother fracture surfaces were observed through SEM micrographs and higher d-spacing was found in X-ray diffraction (XRD) patterns. The PMMA/SiC composite films prepared were suitable to be used in sporting goods, additive manufacturing, and environmental and protective coatings.

Development and Characterization of Lyophilized Chondroitin Sulfate-Loaded Solid Lipid Nanoparticles: Encapsulation Efficiency and Stability

This study explores the development and characterization of lyophilized chondroitin sulfate (CHON)-loaded solid lipid nanoparticles (SLN) as an innovative platform for advanced drug delivery. Background/Objectives: Solid lipid nanoparticles are increasingly recognized for their biocompatibility, their ability to encapsulate diverse compounds, their capacity to enhance drug stability, their bioavailability, and their therapeutic efficacy. Methods: CHON, a naturally occurring glycosaminoglycan with anti-inflammatory and regenerative properties, was integrated into SLN formulations using the hot microemulsion technique. Two formulations (SLN-1 and SLN-2) were produced and optimized by evaluating critical physicochemical properties such as particle size, zeta potential, encapsulation efficiency (EE%), and stability. The lyophilization process, with the addition of various cryoprotectants, revealed trehalose to be the most effective agent in maintaining nanoparticle integrity and functional properties. Results: Morphological analyses using transmission electron microscopy (TEM) and atomic force microscopy (AFM) confirmed the dimensions of the nanoscales and their structural uniformity. Differential scanning calorimetry (DSC) and X-ray diffraction (XRD) revealed minimal excipient interaction with CHON, ensuring formulation stability. Stability studies under different environmental conditions highlighted that SLN-2 is the most stable formulation, maintaining superior encapsulation efficiency (≥88%) and particle size consistency over time. Conclusions: These findings underscore the potential of CHON-loaded SLNs as promising candidates for targeted, sustained-release therapies in the treatment of inflammatory and degenerative diseases.

Flexible and lead-free polymer composites for X-ray shielding: comparison of polyvinyl chloride matrix filled with nanoparticles of tungsten oxides.

Polymer nanocomposites have been investigated as lightweight and suitable alternatives to lead-based clothing. The present study aims to fabricate flexible, lead-free, X-ray-shielding composites using a polyvinyl chloride (PVC) matrix and different nanostructures. Four different nanostructures containing impure tungsten oxide, tungsten oxide (WO3), barium tungstate (BaWO4), and bismuth tungstate (Bi2WO6) were synthesized through various methods. Subsequently, their morphological characteristics were determined by X-ray diffraction (XRD) and scanning electron microscopy (SEM). Also, energy-dispersive X-ray spectroscopy (EDS) analysis was performed to establish the presence of the filler in the PVC matrix. Two different weight ratios of these nanostructures (20% wt and 50% wt) were used to produce the PVC composites. To investigate attenuation parameters, the prepared composites were irradiated with X-rays at tube voltages of 40, 80, and 120kV. The results showed that the PVC composites containing 20% wt Bi2WO6 had the highest linear attenuation coefficient (µ) at all three voltages. Furthermore, they had the lowest half-value layer (HVL), tenth-value layer (TVL), and 0.5mm equivalent lead thickness values at each of the three voltages. The PVC composites containing 50% wt Bi2WO6 had attenuation coefficients greater than those reported for PbO at all three X-ray voltages. Among the studied tungsten nanostructures, bismuth tungstate had the best attenuation performance for X-ray protection. Additionally, this composite is light, flexible, and non-toxic, making it a promising alternative to lead aprons.

Geochemical partitioning and leaching behaviour of geogenic contaminants from the partially weathered rocks in chronic kidney disease of unknown etiology (CKDu) endemic regions in Sri Lanka.

Studies regarding geochemical partitioning and leaching behavior of Hofmeister ions, which is considered as a risk/causative factor for chronic kidney disease of unknown etiology (CKDu), are scarce. Therefore, Hofmeister ions' leaching behavior of partially weathered rocks from CKDu endemic (Girandurukotte) and non-endemic (Sewanagala) areas, Sri Lanka were compared. Rock mineralogy was analyzed using X-ray Diffraction, and total ion contents were determined using alkaline and acid digestions. Leaching experiments were conducted for powdered rocks using HCO3- rich water and deionized water (DI) to determine the kinetics of Hofmeister ion release into groundwater. Fluoride fractionation in rocks was determined through a sequential extraction. The most abundant ions in both rocks from CKDu endemic and non-endemic areas were Cl-; possibly due to carbonate and silicate minerals and Mg2+; possibly due to biotite minerals. Maximum leaching capacities of Hofmeister ions; F-, Cl-, SO42-, K+, Mg2+, Ca2+ were higher with HCO3- rich water compared to deionized water in both rocks from Girandurukotte (F-HCO3: 5.51mg/kg > F-DI: 2.62mg/kg) and Sewanagala (F-HCO3: 6.24mg/kg > F-DI: 3.78mg/kg). This F- variation might be due to the higher exchangeable fraction in the rock from Sewanagala (2.027mg/kg) compared to Girandurukotte (0.963mg/kg). Although, the organic matter bound F- fraction in the rock from Girandurukotte (47.62mg/kg) was higher than that of Sewanagala (31.66mg/kg). However, the cumulative effect of exchangeable, carbonate bound, Fe-Mn oxide bound, and organic matter bound F- fraction in the rock from Girandurukotte was higher (52.6%) compared to Sewanagala, making F- a possible risk factor for CKDu.

Study on the performance of laser cladding Ni-based WC60 composite coatings

Nickel-based Tungsten Carbide (WC) materials have excellent wear resistance and high temperature stability. They are prone to cracking during laser cladding due to the rapid cooling and heating characteristics. The sensitivity of cracking differs when cladding different substrates, which is a bottleneck for the industry. Quantitatively revealing the laser cladding mechanism of nickel-based WC is significant for optimizing the process. In this paper, a coupling model of the thermal field, flow field, and stress field was established for the laser cladding of nickel-based WC60 on a 42CrMo substrate. The model considered the influence of the powder absorption, surface tension and buoyancy on the flow for liquid metal and focused on analyzing the transient evolution during laser cladding. Cladding samples were prepared and subjected to the X-Ray Diffraction (XRD), Scanning Electron Microscope (SEM), Energy Dispersive Spectroscopy (EDS), and microhardness characterization experiments. The morphology and mechanical properties of WC60 based on nickel were observed, and its solidification characteristics were analyzed. The calculations show that the maximum temperature during laser cladding reaches 2529 K, forming an upward Marangoni flow with a maximum velocity of 0.25 m/s. The thermal stress of the cladding layer reaches 616 MPa, and the residual stress reaches 647 MPa. The experiments show that WC particles are spherical and exist in the cladding layer as hard phases, deposited in the middle and lower parts of the cladding layer, which effectively enhances the hardness of cladding layer. WC particles impede columnar crystal growth, and some WC particle boundaries undergo melting, leading to the diffusion of tungsten elements into the cladding layer. This study provides a theoretical basis for optimizing the laser cladding process of nickel-based WC and improving the coating performance.