Diffractometer Research Articles

Brownish Green Fired Clay Tiles Produced by Valorizing Green Glass Cullet and Sediment Soil

This paper aims to valorize waste materials for producing eco-friendly fired clay tiles. Green glass cullet and the water supply process waste; sediment soil have been utilized. In addition, local white clay is used to mix with waste materials for promoting the plasticity and easily forming of specimens. The Triaxial diagram has been employed to construct the formulas. Mixture’s formulation of this experiment consists of 23 formulas. Test samples are fired at temperature 950 °C. Physical properties of fired specimens are carried out and compared with Thailand Industrial Standards. The results show that formula A6 can pass TIS. 2508-2555 wall tiles of medium water absorption series. However, A6 only utilize 10% of sediment soil. Therefore, increasing sintering temperature to 1,050 °C for utilizing higher content of sediment soil has been examined. Twelve formulas of group A and C are selected to be further investigated. Results show that formula A6 and C6 can achieve TIS. 2508-2555. Formula C6 utilizing 30% and 60% of sediment soil and green glass cullet obtain the highest strength and lowest water absorption. Analyzing microstructure of this formula by Scanning Electron Microscope has found glassy phases. Furthermore, Wollastonite 2M, Nepheline and Albite are identified by X-Ray Diffractometer. It can be summarized that sediment soil mixed up with green glass cullet and local white clay can develop brownish green color fired clay tiles which can be further applied to the production of local ceramic factory.

Adsorption of Tricyclazole and 2,4-Dichlorophenoxyacetic Acid onto Biochar Produced from Anaerobically Digested Sludge

Anaerobically digested sludge-derived biochar was produced through pyrolysis at 700 °C, called BC700. BC700 was characterized using a scanning electron microscope (SEM), X-ray diffractometer (XRD), Fourier-transform infrared spectroscopy (FTIR), and the Brunauer–Emmett–Teller (BET) method. The factors influencing the adsorption process and the mechanism involved in adsorbing tricyclazole and 2,4-D in single and binary systems were revealed. The theoretical maximum adsorption capacities of BC700 for tricyclazole and 2,4-D in a single system were 11.86 mg/g and 7.89 mg/g, respectively. In the binary system, the theoretical saturated adsorptive capacities of tricyclazole and 2,4-D were 5.27 mg/g and 3.20 mg/g, respectively. The adsorption of tricyclazole and 2,4-D by BC700, whether in single or binary systems, matched closely with the Freundlich isotherm and the pseudo-second-order model. This study indicates that anaerobically digested sludge-derived biochar is potentially valuable for removing pesticide contamination in surface water.

Effect of SiC Contents on Wear Resistance Performance of Electro-Codeposited Ni-SiC Composite Coatings

This paper focuses on the wear resistance performance of Ni-SiC composite coatings with various contents of SiC particles. The coatings were characterized via a scanning electron microscope (SEM), X-ray diffractometer (XRD), and transmission electron microscopy (TEM), and the wear behaviors of different coatings were tested. The results show that SiC particle incorporation results in a nanocrystalline metal matrix and nanotwins in nickel nanograins. The microhardness and wear resistance Ni-SiC composite coatings increased with the increasing SiC content. Microhardness was improved due to the grain-refinement strengthening effect and the presence of a nanotwin structure. The dominant wear mechanism was described in two stages: the first stage involves the interaction of SiC particles/the counter ball, and the second stage involves the formation of the oxide film its breaking up into wear debris. A higher SiC content increased the duration of the first stage and slowed down the rate of breaking up into debris, thereby decreasing the wear rate.

Influence of Reinforcing nano-Al<sub>2</sub>O<sub>3</sub> Particles on Microstructure and Hardness Properties of HVOF Sprayed 80Ni20Cr Coatings

80Ni20Cr coatings produced by high-velocity oxygen fuel (HVOF) thermal spray technique are novel and widely used to improve the corrosion and wear resistance of metal and steel components in many applications, especially in coal-fired power plants. The present study investigated the effects of nano-Al2O3 at 0.5 wt.% on the microstructure of HVOF-sprayed 80Ni20Cr coating deposited on AISI 304L steels corresponding to its coating hardness. The coating was successfully sprayed with a thickness of 150 – 180 µm. The microstructure and phase formed by the coating were analyzed by a field emission electron microscope (FE-SEM) and an X-ray diffractometer (XRD). Synchrotron X-ray fluorescence spectroscopy (SRXRF) was used to confirm the Cr solid solution in the Ni-based coating. The presence of the nano-Al2O3 phase in the 80Ni20Cr coating was characterized by electron backscattered diffraction (EBSD). The nano-Al2O3 particles were homogenously distributed in the coating layers. The incorporation of nano-Al2O3 into 80Ni20Cr enhanced coating characteristics by decreasing surface roughness by 23% and increasing coating hardness by around 4%.

Marble-Looking Fired Clay Tiles Produced by Utilizing Local Clay and Glass Cullet

This research is aim at developing marble-looking fired clay tile by utilizing waste glass cullet (CGC) mixed up with local plastic clay, sediment soil, and laterite clay. Boric oxide is also used as sintering aid. The experimental formulation is divided into 3 groups (A, B, and C) with 27 formulas. Test samples are moulded at 100 bar by Uni-axial pressing in dimension 50 x 100 x 7 mm and fried at temperature 850 °C. The initial results show that all formulas can develop marble texture and achieve Thai Industrial Standard TIS 2508-2555. Reducing firing temperature to 800 °C is the further investigation. However, formulas consisting 90% glass cullet are not selected, due to difficulty of molding workpieces. The final results of firing 800o C show that formula A6 containing 15% Plastic clay, 85% glass cullet, 2% boric oxide has the highest bending strength and lowest water absorption (<1%). Its properties are similar to formula C6 containing 15% laterite soil 85% glass cullet, 2% boric oxide. They can pass Thai Industrial Standard TIS 2508-2555 Floor Tiles BIb. Analyzing microstructure the fired specimens of these formulas by Scanning Electron Microscope has found glassy phases and dense matrix structures. Furthermore, Nepheline, Quartz, Cristobalite, Wollastonite, Devitrite, and Albite are identified by X-Ray Diffractometer. It can be summarized that marble texture surface fired clay tile can be developed by utilizing waste glass and low cost local materials.

Characterization and acid leaching beneficiation studies of Anka (Zamfara State, Nigeria) copper ore deposit

The chemical and mineralogical characterization of the Anka copper was examined and its susceptibility to H2SO4 acid leaching was assessed. A crude sample of the ore, weighing 5 kg, was sourced from the mines, communiated, homogenized, and characterised the crude sample. A 100 g fraction of the crushed sample was subjected to fractional sieve analysis and each sieve retained was chemically analysed. The leaching process was carried out on 100 g of -125+90 µm sieve size fraction using H2SO4 acid and the resulting product was chemically analyzed. The characterization result reveals 42.271% CuO using the energy dispersive x-ray fluorescence spectrometer and the x-ray diffractometer shows that the ore is mainly composed of Cu-carbonate hydroxide in the form of malachite mineral. The scanning electron microscope micrograph suggests that the ore contains dispersed grains of sodium aluminium silicate and copper carbonate hydroxide in a silica-dominated matrix. The ore's liberation size was determined to be at the sieve size of -125+90 μm. Finally, the ore was discovered to be responsive to the H2SO4 acid leaching operation, leading to an enrichment of the feed from 42.27% Cu to a pregnant solution of 52.51% Cu and the residue from the leaching was analyzed to be 4.69% Cu.

Investigation into the cavitation erosion of rolled Ti6Al4V titanium alloy strengthened by the ultrasonic-assisted laser shock peening process

The novel process known as ultrasonic-assisted laser shock peening (ULSP) is conducted on hot rolled Ti6Al4V titanium alloy with polished surface to improve its cavitation erosion (CE) resistance. The microstructure and phase structure were investigated by transmission electron microscope and X-Ray diffractometer. The microhardness and residual stress were measured by microhardness tester and X-Ray residual stress analyzer. After that, the CE mass loss and morphology were analyzed through high-precision analytical balance and scanning electron microscope to reveal the CE resistance mechanism of ULSP. The results show that ULSP treatment causes plastic deformation at the surface layer, resulting in refined grains and complex dislocation structures. The aforementioned process produces a hardened layer and compressive residual stress (CRS) layer with notable amplitude and deep influence. The surface microhardness of the ULSP-9J specimen is 410 ± 4 HV, which is a 14.8 % increase compared to the LSP-9J specimen. The CRS of the ULSP-9J specimen is −329 ± 6 MPa. As a result, it is vital in preventing the formation and propagation of CE cracks, strengthening the material's resistance to CE damage, reducing mass loss, and enhancing the overall morphology of CE.

Investigating the Effects of Transition Metals and Activated Carbon on Hydrogenation Characteristics of Severely Deformed ZK60 Processed by High-Energy Ball Milling.

The synergic effects of activated carbon and transition metals on the hydrogenation characteristics of commercial ZK60 magnesium alloy were investigated. Severe plastic deformation was performed using equal-channel angular pressing with an internal die angle of 120° and preheating at 300 °C. The ZK60 alloy samples were processed for 12 passes using route BA. The deformed ZK60 alloy powder was blended with activated carbon and different concentrations of transition metals (Ag, Pd, Co, Ti, V, Ti) using high-energy ball milling for 20 h at a speed of 1725 rpm. The amount of hydrogen absorbed and its kinetics were calculated using Sievert's apparatus at the higher number of cycles at a 300 °C ab/desorption temperature. The microstructure of the powder was analyzed using an X-ray diffractometer and scanning electron microscope. The results indicated that 5 wt% activated carbon presented the maximum hydrogen absorption capacity of 6.2 wt%. The optimal hydrogen absorption capacities were 7.1 wt%, 6.8 wt%, 6.7 wt%, 6.64 wt%, 6.65 wt%, and 7.06 wt% for 0.5 Ag, 0.3 Co, 0.1 Al, 0.5 Pd, 2 Ti, and 0.5 V, respectively. The hydrogen absorption capacities were reduced by 35.21%, 26.47%, 41.79%, 21.68%, 26.31%, and 26.34% after 100 cycles for 5C0.5Ag, 5C0.3Co, 5C0.1Al, 5C0.5Pd, 2Ti, and 5C0.5V, respectively. Hydrogen absorption kinetics were significantly improved so that more than 90% of hydrogen was absorbed within five minutes.

Synthesis of Ag-Doped Lanthanum Nanoparticles using Simple Wet Chemical Process in Alkaline Medium; and Characterization of Optical, Morphological and Structural Properties

The manufacturing of doped semiconductor Ag2O.La2O3 (Ag-La) nanoparticles (NPs) in an alkaline medium at 60–70 °C is described in this paper, utilising a straightforward wet chemical procedure. Numerous tools are used to characterise Ag-La NPs, such as ultraviolet/visible spectroscopy (UV/Vis.), field emission scanning electron microscopy (FE-SEM), Fourier transform infrared spectroscopy (FTIR), and powder X-ray diffractometer (XRD). An X-ray diffraction analysis revealed that the Ag-doped Nps are polycrystalline in nature and crystallise in a hexagonal phase with crystallites oriented in various directions. The morphology of the particles shows layers of aggregation of different sized and shaped nanosheets. Studies on their optical properties, however, have revealed that absorption takes place in the 270–291 nm range and that the transmission value, which ranges from 30 to 64%, is influenced by the temperature during annealing. An increase in annealing temperature results in a corresponding drop in band gap energy, from 4.27 to 4.10 eV.

An amperometric stability study of titanium dioxide nanoparticle layer on interdigitated electrode contact based on morphology, structure, and surface-induced response

This paper investigates the amperometric stability of a Titanium Dioxide (TiO2) nanoparticle layer on an interdigitated electrode (IDE) to develop stable electronic devices. The devices were tested with varying numbers of spin-coat layers and annealing temperatures to achieve a TiO2 nanoparticle layer with high crystallinity. Device fabrication involved coating a TiO2 solution onto a silicon dioxide (SiO2) wafer with an IDE photomask. The devices were characterized using a Field-emission Scanning Electron Microscope (FESEM) and X-ray Diffractometer (XRD) to verify the crystallinity of the TiO2. Current-voltage (I-V) curves and real-time current measurements were also conducted to analyze the electrical properties of the device. FESEM results indicate that increasing the number of spin-coat layers and annealing temperature enhances the clarity of the spherical shape of TiO2 nanoparticles and produces highly crystalline nanoparticles, as confirmed by XRD analysis. In terms of electrical analysis, the device exhibited a sharp increase in current, maintaining a range of 2.5 nA to 10 nA. This concludes that the TiO2 device is highly sensitive, with excellent repeatability and response time, making it suitable for practical applications.

Insight into the Structural and Performance Correlation of Photocatalytic TiO2/Cu Composite Films Prepared by Magnetron Sputtering Method

Photocatalysis technology, as an efficient and safe environmentally friendly purification technique, has garnered significant attention and interest. Traditional TiO2 photocatalytic materials still face limitations in practical applications, hindering their widespread adoption. The research prepared TiO2/Cu films with different Cu contents using a magnetron sputtering multi-target co-deposition technique. The incorporation of Cu significantly enhances the antibacterial properties and visible light response of the films. The effects of different Cu contents on the microstructure, surface morphology, wettability, antibacterial properties, and visible light response of the films were investigated using an X-ray diffractometer, X-ray photoelectron spectrometer, field emission scanning electron microscope, confocal laser scanning microscope, Ultraviolet–visible spectrophotometer, and contact angle goniometer. The results showed that the prepared TiO2/Cu films were mainly composed of the rutile TiO2 phase and face-center cubic Cu phase. The introduction of Cu affected the crystal orientation of TiO2 and refined the grain size of the films. With the increase in Cu content, the surface roughness of the films first decreased and then increased. The water contact angle of the films first increased and then decreased, and the film exhibited optimal hydrophobicity when the Cu target power was 10 W. The TiO2/Cu films showed good antibacterial properties against Escherichia coli and Staphylococcus aureus. The introduction of Cu shifted the absorption edge of the films to the red region, significantly narrowed the band gap width to 2.5 eV, and broadened the light response range of the films to the visible light region.

Износостойкость и коррозионное поведение Cu-Ti-покрытий в растворе SBF

Introduction. Currently, titanium and its alloys have become the most popular metal implantable biomaterials. However, the main disadvantage of titanium alloys is low wear resistance due to high viscosity. It is known that copper-titanium coatings effectively improve the antibacterial properties of titanium alloy and at the same time increase its wear resistance. Purpose of the work is to study the effects of a solution simulating body fluid on corrosion properties, friction coefficient and the wear of copper-titanium coatings obtained by electrospark deposition method of the Ti-6Al-4V alloy. Method. A non-localized electrode consisting of copper and titanium granules in various ratios was used to form copper-titanium coatings on a titanium alloy by electrospark deposition. The structure of the coatings was examined using a DRON-7 X-ray diffractometer in Cu-Kα radiation and an X-max 80 energy dispersive spectrometer. The antibacterial activity of the deposited Cu-Ti coatings was studied on a non-pathogenic gram-negative culture of Escherichia coli. Polarization tests in SBF solution were carried out using a P-40X potentiostat with an impedance measurement module. The metal content in the SBF solution after immersion of the samples was measured using an ICP-MS 2000 mass spectrometer. The tribological characteristics of the coatings according to the ASTM G99-17 standard using the “ball-on-disk” scheme with sliding friction in the SBF solution at loads of 10 and 25 N were examined. Results and discussions. It is shown that the bactericidal activity of Cu-Ti coated samples to a non-pathogenic culture of Escherichia coli increased monotonously with an increase in copper content. With copper concentration increasing, the corrosion current density of the coatings increased from 3.455 to 17.570 μA/cm2. It is shown that the SBF solution accelerates the wear of a titanium alloy many times over due to its interaction with the electrolyte via the oxidative wear mechanism. The use of Cu-Ti coatings allows reducing the friction coefficient and greatly decreasing the wear of Ti-6Al-4V alloy in the presence of an electrolyte.

Study of the Characteristics of Ba0.6Sr0.4Ti1-xMnxO3-Film Resistance Random Access Memory Devices.

In this study, Ba0.6Sr0.4Ti1-xMnxO3 ceramics were fabricated by a novel ball milling technique followed by spin-coating to produce thin-film resistive memories. Measurements were made using field emission scanning electron microscopes, atomic force microscopes, X-ray diffractometers, and precision power meters to observe, analyze, and calculate surface microstructures, roughness, crystalline phases, half-height widths, and memory characteristics. Firstly, the effect of different sintering methods with different substitution ratios of Mn4+ for Ti4+ was studied. The surface microstructural changes of the films prepared by the one-time sintering method were compared with those of the solid-state reaction method, and the effects of substituting a small amount of Ti4+ with Mn4+ on the physical properties were analyzed. Finally, the optimal parameters obtained in the first part of the experiment were used for the fabrication of the thin-film resistive memory devices. The voltage and current characteristics, continuous operation times, conduction mechanisms, activation energies, and hopping distances of two types of thin-film resistive memory devices, BST and BSTM, were measured and studied under different compliance currents.

Protein expression, purification, crystallization and crystallographic studies of BPSL0741 from Burkholderia pseudomallei.

Burkholderia pseudomallei is the causative agent of the lethal disease melioidosis. This bacterium infects animals and humans and is increasingly resistant to multiple antibiotics. Recently, genes associated with survival of the bacterium in the infected host have been identified. One of these genes, bpsl0741, is annotated as a hypothetical protein of 185 amino acids. Here, recombinant BPSL0741 (rBPSL0741) protein was expressed, purified, verified by mass spectrometry, crystallized and analyzed by X-ray diffraction. rBPSL0741 was crystallized by vapor diffusion using a reservoir solution consisting of 0.2 M ammonium acetate, 0.1 M sodium acetate trihydrate pH 4.6, 30% PEG 4000. The crystals diffracted to 2.1 Å resolution using an in-house X-ray diffractometer and belonged to an orthorhombic space group, with unit-cell parameters a = 62.92, b = 64.57, c=89.16 Å. The Matthews coefficient (VM) was calculated to be 2.18 Å3 Da-1, suggesting the presence of two molecules per asymmetric unit and an estimated solvent content of 43.5%. The crystal was deemed to be suitable for further structural studies, which are currently ongoing.

Effect of the Atmosphere on the Properties of Aluminum Anodizing

This study aims to quantify the effect of process parameters on the anodizing of Al6061 aluminum. To achieve this, studies on layer thickness, the porosity of the anodized surface, electrochemical techniques, X-ray diffraction, grain size estimation, and statistical analysis were conducted for three different atmospheres (without air, air, and oxygen). Parameter levels were established as follows: temperature (30 °C, 45 °C, and 60 °C), time (20 min, 40 min, and 60 min), electrolyte concentration (0.5 M), voltage (9 V), and current intensity (0.600 A). A 33 experimental design (three factors, three levels) was proposed, and mathematical models were obtained using general factorial design. The experimental design was used to determine the three most important variables in the optimal condition. A total of 27 tests were conducted using sulfuric acid electrolytic solutions, of which 12 samples were selected by the factorial design method, which simultaneously evaluates the effects of factors and their interactions in a single experiment. Measurement of porosity and oxide layer thickness was performed using scanning electron microscopy. The purity of the anodic layer formed was characterized using X-ray diffraction techniques with a vertical goniometer X-ray diffractometer. The electrochemical behavior is presented through potentiodynamic polarization curves for the anodic layer. A general factorial design and an analysis of variance (ANOVA) were conducted to establish the significant factors for layer thickness, grain size, and reaction rate. Finally, the best results and their parameters for each response are presented.

Experimental and theoretical results of gamma shielding features for copper based shape memory alloys

In this study, the gamma ray attenuation characteristics for CuAlNi shape memory alloys with different proportions of Sn doping was investigated. We determined the mass attenuation coefficient (μ/ρ) of CuAlNiSn alloys both experimentally and theoretically within an energy range of 59.5–1332.5 keV. The experimental measurements were made using a high purity Germanium detector (HPGe) and theoretical calculations were made using WinXCOM program. To evaluate the gamma radiation shielding abilities of the alloy samples, the obtained (μ/ρ) values were used to determine the gamma protection parameters μ, HVL, TVL, MFP, and Zeff. In addition, the radiation protection efficiency (RPE) parameter was determined using gamma ray intensities in the absence and presence of the attenuator. Further analysis of the samples was conducted using a Rigaku Miniflex 600 model computer-controlled X-ray diffractometer (CuKα & λ = 1.5405 A0). The crystallographic structure of the alloys before and after irradiation was investigated. Other analysis which include EDX analysis (to investigate the chemical content) and SEM analysis (to investigate the microstructure) were conducted. According to result outcomes, gamma ray radiation did not affect the shape memory properties of structure. Another interesting observation is that, the radiation attenuation properties increase with increasing Sn concentration. Finally, we discovered that the CuAlNiSn4 alloy (which has the highest doping rate) provides good protection especially at low energy levels.

Mineral composition of lake Sabakty sediments as an indicator of paleoclimate, Southern Urals, Russia

Relevance. Reconstruction of climatic changes based on the lacustrine sediments of lakes makes it possible to identify climatic trends and events in the late Quaternary. The Urals is considered as one of the climatic divisions, therefore, studies of the conditions of lake sedimentation, including climatic ones, are relevant in this area. Aim. To study mineral composition as an indicator of paleoclimate of Lake Sabakty sediments. Object. Core of Lake Sabakty sediments (length is 298 cm). The age of the core is ~25 thousand years old. Materials and methods. Sampling was carried out taking into account seismoacoustic data, lithological description, as well as measurements of magnetic susceptibility and radiometric dating data. The granulometric analysis was carried out by laser granulometry using a Bluewave particle size analyzer (Microtrac, USA) combined with a sample loading and circulation system with an integrated ultrasonic dispersant. Mineral composition of the sediments was determined using the D2 PHASER X-ray diffractometer and the Merlin auto-emission scanning electron microscope. Results. The predominance of the siltstone fraction was established. The mineral composition is characterized by the predominance of allotigenic minerals in sediments (quartz, microcline, albite, mica, chlorite, mixed-layer clay minerals, hornblende, kaolinite) according to X-ray diffraction and electron microscopy. Autigenic minerals include biogenic silica (cristobalite, tridymite), pyrite, carbonates (calcite, dolomite), sulfates (gypsum, barite). Conclusions. The ratio of allogenic and autogenic components reflects the changes in the accommodation of the reservoir and the supply of clastic material associated with changes in climate humidity. Changes in climate humidity are reflected in changes in the contents of carbonate and sulfate minerals. At the beginning of sedimentation, Lake Sabakty was shallow and mineralized due to climate aridization, which probably included the global Bond 8 event (~26000–11700 BP). The study of the mineral composition of the sediments of Lake Sabakty allowed us to establish the events of climate aridization: ~10000 BP, ~7600 BP, ~6900 BP ~1900 BP and ~1400 BP. In Sabakty Lake, there is a bright episode of a decrease in climate humidity in the range of ~7300-5200 BP, which is marked by an increase in carbonate content up to 70% and the detection of gypsum at ~6900 BP.

Effects of Cr3C2 addition on microstructure and corrosion properties of Cr3C2/15–5PH composite coatings on 12Cr13 by laser cladding

The application of laser cladding technology to prepare iron-based composite coatings has significant advantages in improving the surface properties of 12Cr13 stainless steel. 15–5PH composite coatings reinforced with Cr3C2 particles of different contents (0–25 wt%) were prepared on the 12Cr13 surface by the coaxial powder feeding laser cladding system. The microstructure, phase composition, element distribution, corrosion resistance and corrosion mechanism of the composite coatings were analyzed and studied by optical microscope, scanning electron microscope, X-ray energy dispersive spectrometer, X-ray diffractometer and electrochemical workstation. The results indicated that the Cr3C2/15–5PH composite coatings exhibited good macroscopic morphology and dilution rate under appropriate laser cladding process parameters. The addition of Cr3C2 particles changed the main phase from α-Fe to γ-Fe and formed new carbide phases (M7C3 and Cr23C6). The Cr3C2/15–5PH composite coatings exhibited a typical microstructure with rapid solidification characteristics, and the addition of Cr3C2 significantly changed the grain size. The distribution of Fe, Ni, and Cr elements in the composite coatings was uniform, and the relative content of Cr elements increased and remained at high level. The 15-5PH composite coating with 15 wt% Cr3C2 exhibited a lower corrosion current density and higher impedance modulus values. The surface of this composite coating had no obvious corrosion pits, and the passive film effectively retarded the further corrosion by the Cl- ions on the surface during the electrochemical corrosion process. By preparing a 15–5PH composite coating with 15 wt% Cr3C2 on the surface of 12Cr13, the corrosion resistance of the surface can be effectively improved.

Production Sericin/Poly(Vinyl Alcohol) Blend Membranes Containing One‐Step Synthesized Silver Nanoparticles by UV Radiation for Obtaining Versatile Antibacterial Materials

AbstractIn this study, silver nanoparticles (AgNPs) were in‐situ synthesized in silk sericin/poly(vinyl alcohol) (SS/PVA) mixtures by an easy one‐step synthesis method with the presence of ultraviolet (UV) radiation. Then, the SS/PVA composite membranes containing AgNPs were obtained by solvent casting method. The chemical structures of the membranes were investigated by fourier‐transform infrared spectroscopy (FTIR) and results showed that the membranes were a mixture of silk sericin and PVA. The morphological features of the membranes were investigated by field emission scanning electron microscopy (FE‐SEM) and it was seen that AgNPs containing membranes have heterogeneous structures. Energy dispersive spectroscopy (EDS) analysis revealed that the membranes contain carbon, oxygen, nitrogen, sulfur and silver. X‐ray diffractometer (XRD) and thermogravimetric (TGA) analyses also proved the presence of AgNPs in the structure of membranes. The antibacterial activities of membranes containing AgNPs were investigated on Staphylococcus aureus and Escherichia coli bacteria with disk diffusion test and liquid culture medium incubation. It was found that SS/PVA membranes containing 5 and 10 mM AgNPs have quite high antibacterial activity on both types of bacteria. The functional SS/PVA membranes have capacity to be used in biomedical applications such as wound care materials.

Synthesis and evaluation of thermal and optical properites of Fe2AlB2 phase alloy for thermal control in space applications

Ternary laminated Fe2AlB2 alloy holds its significance in displaying high strength, damage tolerance, oxidation and radiation cracking resistance. It is synthesized through a pressureless sintering route from elemental powders. Synthesis of Fe2AlB2 is studied from two different molar ratios (2/1/2 and 2/1.5/2) and three different sintering temperatures (1100°C, 1150 °C and 1200 °C). Phase analysis is carried out through an x-ray diffractometer and scanning electron microscopy (SEM). In addition, thermal decomposition, thermal conductivity and absorbance spectra are examined. Fe2AlB2 begins to decompose at 1169 °C into borides and aluminides. Thermal conductivity and diffusivity of Fe2AlB2 decreases with increase in temperature. Lower solar reflectivity and high thermal emittance of Fe2AlB2 implies the thermal control and optical behavior that can be expected for extreme space environments.