بحوث سكوبس — أمير نجاح سعود الحميري

A novel cellulose-silica hybrid aerogel was synthesised via a sol–gel technique and investigated as a sustainable adsorbent for oxidative-adsorptive desulfurization (OADS) of dibenzothiophene (DBT) from diesel fuel. The material demonstrated excellent physicochemical properties such as a high surface area of 357.9 m2/g, mesoporous structure of 7.45 nm average pore size, and strong hydrophobicity interpreted by its high contact angle of 129.4° combined with tailored amphiphilic surface chemistry. Collectively, they enabled the selective and efficient uptake of polar oxidised sulfur species (DBTO2). The synergistic effects of temperature (25–100 °C) and ultrasonic frequency (20–60 kHz) on the removal efficiency of sulfur were systematically evaluated. A maximum removal efficiency of 90.3 % was achieved at 100 °C and 60 kHz in addition to an apparent adsorption capacity of 529.9 mg/g which surpasses previously reported materials under diesel fuel conditions. Kinetic analysis revealed that the pseudo-second-order model best described the adsorption process and indicated a chemisorption-dominant mechanism whereas the intraparticle diffusion model suggested a multistep adsorption process. Thermodynamic parameters confirmed the spontaneous (ΔG° < 0) and endothermic (ΔH° > 0) nature of the process. The hybrid aerogel preserved over 93 % of its initial performance after five reuse cycles, which confirms its excellent structural resilience and regeneration ability. Additionally, a two-hidden-layer artificial neural network (ANN) trained by the Bayesian regularisation algorithm achieved excellent predictive accuracy (R2 = 0.9995 for training, R2 = 0.9769 for testing, MSE = 0.0905 for training, MSE = 2.4386 for testing), offering a valuable tool for process optimization. Overall, this study proposes a scalable, metal-free, and high-performance desulfurization platform, combining green material design with superior cavitation-enhanced oxidation and machine learning-based prediction. © 2025 Elsevier Ltd.

Engine mounts require materials that combine static load bearing capacity with effective vibration damping. This study examines styrene–butadiene rubber (SBR) composites modified with novolac resin and nano-sized SiO2 to optimize the balance between stiffness, compression resistance, damping, and resilience for automotive mounts. SBR compounds containing 0–50 pphr novolac and 0–50 pphr nano-SiO2 (various particle sizes) were prepared and characterized. Morphology was examined using SEM; crosslink density and swelling tests were used to assess network formation. Mechanical testing included compression deformation, elastic modulus, fatigue life, and rebound resilience. Viscoelastic behavior was evaluated by dynamic mechanical analysis (tan δ versus temperature). SEM and swelling results indicate increased heterogeneity, filler agglomeration at high loadings, and higher cross link density with novolac and silica. Novolac increased the elastic modulus from 2 MPa (neat SBR) to 9.7 MPa (50 pphr) and reduced compression deformation from 2.8 to 0.35 mm. The addition of 80 nm SiO2 (30–45 pphr) further improved compression resistance (minimum 1.3 mm) and modulus (5.5 MPa). These reinforcements caused a moderate reduction in rebound resilience (from 63 to 54% at optimal silica loading). DMA showed reduced but broadened tan δ peaks for filled composites (0.8–0.9 versus 1.0 for unfilled SBR), indicating preserved, temperature-broadened damping. The optimal formulation (10 pphr novolac + 30–45 pphr nano-SiO2) delivers significantly improved static stiffness and compression resistance while maintaining acceptable resilience and enhanced vibration attenuation due to increased hysteresis. The composition is tunable (e.g., filler content or surface treatment) to meet specific resilience or damping requirements for engine-mount applications. © ASM International 2026.

This study investigated the effects of rolling temperature and rate on the microstructure, wear resistance, and corrosion resistance of ZM21 magnesium sheets. Microstructural analysis revealed that higher rolling temperatures and rates refined the grain structure, producing a higher density of finer grains. Wear tests under dry and corrosive conditions showed that wear rates remained generally low, with the highest rates observed in samples rolled at 375 °C (40% reduction, dry) and 325 °C (80% reduction, corrosive). SEM analysis of worn surfaces revealed thin grooves in Zn-rich regions and linear lines in areas with high Zn content. Corrosion tests indicated a 68% increase in corrosion rate after homogenization compared to the as-cast state. However, rolling at 375 °C reduced the corrosion rate by 24% compared to the as-cast state and 26% to the homogenized state. The higher corrosion rates at elevated rolling temperatures and rates are attributed to increased grain boundary area due to grain refinement. In conclusion, the results demonstrate a complex relationship between rolling parameters, microstructure, and the resulting mechanical and corrosion properties of the ZM21 magnesium alloy. © 2025 Canadian Institute of Mining, Metallurgy and Petroleum.

This study evaluated the antibacterial properties, hemocompatibility, cytotoxicity, and genotoxicity of bioactive glass ceramic-based endodontic cement formulated with various radiopaque active ingredients with varying concentrations (0, 15, and 20 wt%). Antibacterial activity against E. faecalis was assessed using colony-forming unit (CFU) assays. The results showed significant antimicrobial activity of the bioactive glass-based cement, which was enhanced by adding radiopaque active ingredients. Lanthanum oxide exhibited the highest antibacterial activity at a concentration of 20 %, reducing the CFU count from 6,000,000 (control) to 1,190,000. Bismuth oxide and samarium oxide also showed dose-dependent improvements in antibacterial properties. Hemocompatibility analysis revealed that all cement samples, including those containing radiopaque agents, remained nonhemolytic after 1-h- and 24-h incubation, indicating excellent compatibility with human blood. Cell viability testing with the L929 cell line showed that the cement samples achieved the required cell viability threshold of 70 % according to ISO 10993–5:2009 over 1, 3, and 7 days of exposure. Genotoxicity assessment using comet assay revealed no detectable DNA damage in the cement samples compared to the negative control. These comprehensive results confirm the biocompatibility and strong antibacterial properties of the bioactive glass ceramic-based endodontic cement samples containing various radiopacity agents. © 2025 Elsevier Ltd and Techna Group S.r.l.

In this study, glass-ceramics with a weight composition of 40-X% SiO₂, 24.5 % CaO, 14.5 % Na₂O, 6.0 % P₂O₅, 15 % B₂O₃, and X% V₂O₅ (X = 1, 3, and 5) were produced using the melt quenching method. Vanadium pentoxide and boron oxide were suggested to lower production melting temperatures. Several techniques were used to confirm the composition and amorphous nature of the glass-ceramics, including X-ray diffraction (XRD), scanning electron microscopy (SEM), thermogravimetry (TG), energy dispersive spectroscopy (EDS), and differential thermal analysis (DTA). All samples were incubated in simulated body fluid (SBF) solution at 37 °C for 3, 7, 14, and 21 days to determine their bioactivity under in vitro conditions. The XRD pattern indicates insufficient crystalline phase formation, possibly due to V₂O₅ inhibiting apatite growth and promoting amorphous calcium phosphate. Precipitates in the glass-ceramic show increased lattice constants when apatite combines with boron. SEM images reveal surface precipitation and the development of hydroxyapatite (HA) after 21 days of immersion in SBF; EDS analysis confirms the presence of the expected ions. The Fourier Transform Infrared Spectrophotometer (FTIR) analysis shows the dominance of the silicate network in the glass-ceramics, with characteristic bands at specific frequencies. © 2024 Elsevier B.V.

Flue gas is considered a major contributor to greenhouse gas emissions. Among the available separation technologies, pressure swing adsorption (PSA) is widely applied, where the choice of adsorbent critically determines system performance. In this study, hybrid aerogels named MTGO, MTR10, and MTR20 were synthesized to provide heterogeneous surfaces in addition to providing hydroxyl groups as adsorption sites and promoting the adsorption efficiency of carbon dioxide. To determine the most effective adsorbents for capturing CO2, adsorption studies were conducted on the newly developed adsorbents under various conditions. The hybrid aerogels exhibited significant CO2 adsorption capacities, with MTR20 demonstrating the highest performance, attributed to its larger surface area and optimized pore structure. The Avrami model, which captured both the underlying adsorption processes and kinetic behavior, was shown to be the best appropriate for characterizing the adsorption process by kinetic investigations. Isotherm analysis demonstrated that the Freundlich model best described the adsorption behavior, suggesting a heterogeneous, multilayer adsorption process. Moreover, all materials showed exothermic adsorption; MTR20 showed the strongest contacts and the highest spontaneity, suggesting that it might be used for effective CO2 collection at higher temperatures. MTR20 also demonstrated the least amount of decrease in CO2 absorption under various humidity conditions likely due to its high hydrophobicity and low affinity for water. Regeneration experiments confirmed that all materials exhibited excellent stability and reusability across multiple adsorption-desorption cycles, with no significant degradation in performance. © 2025 Elsevier B.V.

This study investigates the effect of zinc alloying (0.2-2%) on the properties of biodegradable magnesium (Mg) alloys produced through powder metallurgy. Prolonged mechanical alloying, cold pressing, and sintering enhanced the hardness of Mg-Zn alloys by 9-12.5% and improved wear resistance, with Zn uniformly distributed in the Mg matrix without intermetallic compounds. Wear tests revealed that simulated body fluid initially reduced wear due to lubrication but later accelerated wear through abrasive–corrosive mechanisms. The results indicated that zinc was uniformly distributed throughout the magnesium matrix. The hardness of the material increased from 40 to 70 HV, and the wear resistance also demonstrated a corresponding improvement. Microstructural analysis revealed an increase in porosity alongside a higher density. Among the alloys tested, MgZn2 showed the best wear resistance, while pure magnesium exhibited the lowest. These findings emphasize the potential of Mg-Zn alloys as bioresorbable materials, with properties closely aligned to the mechanics of bone, paving the way for their application in biomedical fields. © ASM International 2025.

The original online version of this article was revised: One of the co-author’s names was incorrectly listed as Abdulrazzak Ahmed Salehb, and it has been corrected to Abdulrazzak Akroot. © American Coatings Association 2025.

This study presents the development of a multifunctional nanocomposite coating aimed at enhancing the efficiency of solar panels through self-cleaning and cooling properties. The novel coating integrates nanosized zinc oxide (ZnO), silicon dioxide (SiO2), and chlorophyll to address two significant challenges: dust accumulation and thermal management. The results showed that the ZnO coating exhibits the highest visible light transmittance (96.38%), while the combined coating containing ZnO, SiO2, and chlorophyll achieves a balanced transmittance of 93.48%. In terms of UV absorption, chlorophyll significantly enhances the coating's ability to protect underlying materials from UV damage, complemented by ZnO's protective qualities. Furthermore, the coating's thermal emissivity is optimized, with the combined formulation showing the highest emissivity, indicating superior heat management capabilities. Contact angle measurements reveal that the multifunctional coating exhibits hydrophobic properties, contributing to effective self-cleaning by minimizing dust accumulation—evident over a 7-day assessment period. Performance testing indicates that the coated panels demonstrate up to 22.12% improvement in power output and notable cooling enhancements, with surface temperatures decreasing by up to 9.62%. These findings suggest that the proposed nanocomposite coating not only improves energy efficiency by minimizing maintenance needs but also advances the sustainability of solar energy technologies, making it a promising solution for photovoltaic applications, particularly in dust-prone environments. Further research will focus on optimizing the coating's formulation and exploring its long-term performance in real-world conditions. © American Coatings Association 2025.

Due to its ease of processing and excellent thermal and chemical stability, silicone rubber (SR) has become the preferred material for prosthetic socket liners. However, its inherent mechanical weaknesses and low surface free energy challenge durability and adhesion strength. This study aims to improve the mechanical strength, hydrophilic characteristics, and antibacterial effectiveness of silicone rubber used for prosthetic socket liners by optimising the composite formulation that incorporates hydroxyapatite (HA), zinc oxide (ZnO) nanoparticles, and chlorophyll into a silicone rubber matrix. Significant improvements in silicone rubber’s hydrophilicity are attained by incorporating chlorophyll, thus enhancing water absorption capacity. Adding nano-ZnO and nano-HA influences mechanical properties, with aggregation affecting tensile and tear strength. Optimum chlorophyll content is established at 10%, balancing mechanical robustness and water absorption for high-performance denture linings. The composite’s crystalline structure is confirmed by XRD analysis, revealing the presence of ZnO and HA nanoparticles dispersed within the matrix. Antibacterial tests demonstrate significant inhibition against Staphylococcus aureus and Escherichia coli after 24 h of contact. The study successfully formulates a multifunctional nanocomposite with improved performance over conventional silicone, offering the potential for enhanced prosthetic socket viability and infection prevention. © The Author(s), under exclusive licence to Malaysian Rubber Board 2024.

Endodontic cements play a crucial role in root canal treatment by sealing the canal and preventing reinfection. However, existing materials have limitations, including suboptimal bioactivity, handling properties, setting times, and antimicrobial efficacy. This study aimed to develop endodontic cements incorporating bismuth oxide, lanthanum oxide, and samarium oxide, and evaluate their physicochemical and biological properties according to the ISO 6876:2012(12) standard, FTIR, and SEM analyses confirmed the formation of a calcium phosphate apatite layer, indicating the bioactive potential of the cements for tissue regeneration. Rheological testing showed that cements containing glycerin (S1, S2) had improved flowability due to the viscosity-reducing properties of glycerin. Varying the water-to-powder ratios revealed that lower ratios resulted in reduced porosity and enhanced mechanical properties, with bismuth oxide being the most effective additive. Cements containing carboxymethyl cellulose (S3-S5) exhibited optimal flow values due to the dispersion-stabilizing effect of CMC. Antimicrobial evaluation demonstrated that the S2 group, with bismuth oxide, had the highest antibacterial activity (26.51 mm), followed by samarium oxide (24.19 mm) and lanthanum oxide (20.10 mm). Similar trends were observed for the S3 and S4 groups, with bismuth oxide exhibiting the greatest efficacy. Radiopacity analysis showed that all additives significantly increased the values, with bismuth oxide reaching the highest at 7.70 mm Al. Lanthanum oxide and samarium oxide also increased radiopacity to 6.21 mm Al and 7.53 mm Al, respectively. Biocompatibility assessment using human dental pulp stem cells revealed cell viability ranging from 73 to 105% after 1 day, exceeding the 70% biomedical threshold. The developed cements meet the requirements of current legislation and are considered suitable for endodontic applications. © ASM International 2024.

Conventional calcium silicate cements (CSCs) are widely applied in endodontics but often suffer from drawbacks such as long setting times, poor handling, and variable biocompatibility. A novel premixed calcium borate silicate (CBS)–based cement incorporating different radiopacifiers was developed and evaluated to address these limitations. CBS powders were synthesized via melt-quench routes, combined with Bi2O3, La2O3, or Sm2O3 at various loadings, and blended with an optimized hydrogel liquid phase. The resulting cements' physicochemical, biological, and functional properties were systematically assessed. Key tests included setting time, flow, solubility, radiopacity, and ion release measurements; bioactivity analysis via immersion in simulated body fluid; and antibacterial activity against E. faecalis. Cytocompatibility, hemocompatibility, and genotoxicity were examined using L929 fibroblasts through MTT and comet assays. Incorporation of radiopacifiers significantly modified cement performance. Bi2O3 enhanced radiopacity (>7 mm Al) and accelerated setting, while La2O3 and Sm2O3 balanced faster hardening with favorable flow characteristics. All doped formulations showed apatite formation and improved Ca/P ratios, indicating robust bioactivity. Ion release profiles confirmed controlled liberation of Ca2+, P, and Si alongside trace radiopacifier ions. Radiopacified cements achieved >75 % reduction in E. faecalis colony counts, with La2O3 demonstrating the strongest antibacterial effect. Biocompatibility studies revealed that La2O3 maintained fibroblast viability >80 % and improved hemocompatibility, whereas Bi2O3 and Sm2O3 displayed mild concentration-dependent cytotoxicity. Importantly, no formulation induced DNA damage in the comet assay, confirming non-genotoxicity. The novel CBS-based cement system demonstrated excellent radiopacity, rapid setting, strong bioactivity, antibacterial activity, and good overall biocompatibility, with La2O3 emerging as the most balanced additive. These findings support CBS-radiopacifier formulations as promising next-generation endodontic materials, warranting further in vivo and clinical evaluation. © 2025 Elsevier Ltd and Techna Group S.r.l. All rights are reserved, including those for text and data mining, AI training, and similar technologies.

The current study investigates the potential of styrene-butadiene rubber (SBR) nanocomposite reinforced with nano-lead (N-Pb) as a protective shield against gamma radiation emitted from a Cobalt-60 (Co-60) source. The influence of varying N-Pb concentrations (50–300 parts per hundred parts of rubber, pphr) on the structural, morphological, and radiation-shielding characteristics was investigated. The nanocomposite was characterized using several analytical techniques, including X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and scanning electron microscopy (SEM). The results demonstrate that increasing the N-Pb concentration leads to enhanced crystallinity, improved homogeneity, and significantly enhanced gamma radiation shielding capabilities of the material. Notably, the nanocomposite exhibited a substantial decrease in gamma count rate (31.9% reduction with 300 pphr N-Pb), mean free path (81% decrease), half-value layer (77% decrease), and tenth-value layer (87% decrease) as the N-Pb content increased. These findings highlight the promising potential of SBR-N-Pb nanocomposites as a cost-effective and efficient shielding material for various gamma radiation applications. © 2025, S.C. Virtual Company of Physics S.R.L. All rights reserved.

This study produced a non-standard alloy of 85% Mg, 13.5% Al, and 1.5% Si by weight. In-depth microstructural, chemical, and morphological analyses of the secondary β phases formed in the MgAlSi alloy were conducted. The formation processes of the intermetallic phases were also examined. Image processing was applied to the obtained microstructures using the Image-J program. The average alloy had a matrix α phase to secondary β phase ratio of approximately 60/40. Furthermore, a dry and corrosive wear test were applied to the MgAlSi alloy by means of reciprocating motion. The wear rate was calculated to be at least 0.00137 mm3/Nm, indicating that the unique MgAlSi ternary alloy produced had very high wear resistance due to the presence of intermetallic phases. © 2023, American Foundry Society.

Bone tissue engineering seeks to regenerate damaged tissues using biocompatible scaffolds that mimic bone minerals. This study focuses on scaffolds based 45S5 bioactive glass (45% SiO2, 24.5% Na2O, 6% P2O5, 24.5% CaO) doped with boron and lanthanum oxides. These scaffolds, produced via conventional melting, form a hydroxyapatite layer, promoting strong bone integration. Result of DTA, XRD, FTIR, SEM, and EDS, showed doping led to crystalline phase identification, silicate network confirmation, and detection of calcium phosphorus deposits. Doping also increased pH, degradation kinetics, and antibacterial activity. These findings suggest that boron and lanthanum-doped 45S5 scaffolds have potential in bone regeneration applications. © 2024, S.C. Virtual Company of Physics S.R.L. All rights reserved.

Magnesium-zinc alloys offer promising lightweight properties but are prone to oxidation during high-temperature processing and usage. In this study, the oxidation behavior of Mg-Zn alloy was examined according to the inert gas type flow rate, heating rate and alloy amount. Initially, alloys were produced by adding zinc at weight percentages of 0.5%, 1.5%, and 2% using the casting method. The alloys were characterized using X-ray fluorescence (XRF), X-ray Diffraction (XRD), and scanning electron microscope (SEM) analyses, revealing the formation of dendritic Mg-Zn intermetallic within the alloy. The oxidation behavior of these alloys was examined via differential thermal analysis (DTA) and thermogravimetric analysis (TGA), considering factors such as heating rate, gas flow rate, type of protective atmosphere, and amount of alloying element. The results indicated that the onset temperature of oxidation decreased with increasing heating rate. The effect of gas flow rate varied depending on the heating rate and the type of gas. Under a nitrogen atmosphere, conditions with a heating rate of 20°C∙min‒1 and a gas flow rate of 5 cm3∙min‒1 resulted in the least oxidation. In an argon atmosphere, a gas flow rate of 5 cm3∙min‒1 was found to be sufficient to prevent oxidation. However, at a gas flow rate of 1 cm3∙min‒1, a heating rate of 20°C∙min‒1 was more effective in preventing oxidation. The alloying element (zinc) likely reduced oxidation, particularly at the 1.5% addition level, possibly due to the formation of intermetallic compounds. © (2024), (Journal of Metals). All rights reserved.

This study aimed to develop an innovative approach to produce an organic antibacterial composite material by combining acrylic paint and acetamide through a simple mixing method. Acetamide, known for its potent antibacterial properties, underwent a thorough evaluation to assess its effectiveness in the composite. The antibacterial properties were evaluated using established methods such as the minimum inhibitory concentration (MIC) and the agar well diffusion test. These tests provided quantitative and qualitative measures of inhibitory activity against two common bacterial strains, namely S. aureus and S. epidermidis. The results showed a clear correlation between the concentration of acetamide in the composite and its antibacterial activity. Higher concentrations of acetamide led to a significant increase in the effectiveness of the composite material against the targeted bacterial strains. In addition to the antibacterial properties, the mechanical and physical properties of the composite material were also analyzed comprehensively. Parameters such as wettability, swelling ratio and chemical structure were thoroughly investigated using Fourier Transform Infrared (FTIR) analysis. This comprehensive characterization enabled a detailed understanding of the behavior and performance of the composite material. The results of this study are auspicious in the context of operating rooms. The proposed composite antibacterial polymer coatings, utilizing organic or inorganic agents at low concentrations, represent an effective solution to eliminate bacteria and maintain a sterile environment. These coatings can be applied to operating room walls and offer improved infection control and reduced bacterial contamination risk. © 2024, The Author(s), under exclusive license to Springer Nature Switzerland AG.

The main focus of this work is the development and simulation of a prosthesis using a high entropy alloy known as Ti-15Mo-XTa. The selection of this alloy is based on its compatibility with the human body, which is a crucial factor when choosing materials for medical implants. Traditional metal implants can cause several problems for patients, including toxic reactions from the release of metal ions, wear and tear of joint replacements from movement, and structural failure from repetitive loading. To address these concerns, the present study creates a three-dimensional finite element model of the prosthesis using COMSOL software. The model includes both isotropic and anisotropic materials and is subjected to various mechanical loads based on experimental studies. The finite element method is used to analyze the distribution of stress and strain across adjacent elements of the prosthesis. By simulating the behavior of the prosthesis under different loading conditions, valuable insights into its performance and durability can be gained. To assess the static design, the prosthesis is tested using COMSOL simulation software and subjected to loading conditions of 70, 90 and 110 kg. The objective of this assessment is to determine the robustness and ability of the design to withstand real-world mechanical demands. By conducting these simulations and tests, the researchers hope to contribute to the development of improved prostheses that can offer better functionality, longevity and overall patient satisfaction. © 2024, The Author(s), under exclusive license to Springer Nature Switzerland AG.

Melt-derived route was used to prepare modified bioactive glass-ceramic based on the 45S5 composition with the same network connectivity. Their phase composition, sinterability, and bioactivity were studied. A modified composition was proposed using potassium tetraborate (K2B4O7) to reduce the melting temperature during manufacture. The phase composition and the bioactivity was determined by X-ray diffraction and Fourier transform infrared spectroscopy. Furthermore, the antibacterial properties were evaluated against Enterococcus faecalis. The result shows that glass-ceramics already had P–O and C–O bond functional groups on day 2. These bonds are responsible for the creation of the HCA layer. Scanning electron microscopy (SEM) pictures and Energy Dispersive X-ray Spectroscopy (EDX) investigations showed that, after being immersed in SBF solution, a layer of hydroxyapatite (HA) formed on both BG surfaces on day 2 and that by day 21, HCA cluster crystals had developed. Inductively coupled plasma-optical emission spectroscopy metrics of ionic release from the prepared glass-ceramic, mainly calcium and phosphorus ions in SBF solution, revealed that HCA formation occurred on both BG surfaces, which correlated to the increasing pH within 2 days of incubation; furthermore, it exhibited good antibacterial behavior against the Enterococcus faecalis. © 2022 Elsevier Ltd and Techna Group S.r.l.

Bioactive glasses are considered biocompatible materials that form a hydroxyapatite-like layer on the surface that allows strong adhesion to soft and hard tissues. This study aims to develop a method to fabricate a borate silicate ceramic biomaterial with a chemical composition of Ca11Si4B2O22 using sodium metaborate (NaBO2) as a flux. X-ray diffraction (XRD), scanning electron microscopy energy distribution spectrometer (SEM-EDS), and Fourier transform infrared spectrometer (FTIR) were used to analyze the structure, surface composition and chemical bonding of the bioactive borate silicate. In addition, the pH measurements and biodegradability behavior of the fabricated glass structures were investigated after immersion in simulated body fluid for 2, 7, 14, and 21 days, respectively. The results showed that the glass-ceramic structure, which was transferred from the crystalline phase Ca11Si4B2O22 to a hydroxyapatite phase after incubation, started on the second day. In addition, the formed hydroxyapatite crystals developed due to the prolonged immersion time, reflecting biodegradable behavior. The antimicrobial activity of the prepared ceramic showed high inhibitory activity against Enterococcus faecalis and Streptococcus mutans. © 2023 Elsevier Ltd and Techna Group S.r.l.

Magnesium alloys are being studied for their potential as biodegradable metals, and there is a growing need for multipurpose materials, such as those with more than one use. Binary Mg-Ag alloys were developed as implant materials, combining the beneficial qualities of magnesium with silver's well-known compatibility feature. The result shows that as the amount of the added Ag in the cast alloys increased, the secondary phases (Mg4Ag and Mg54Ag17) that appeared in the structure became more pronounced, and the grains became finer. The best percentage of Ag was found to be 3%, so Ca, Zn and Nd were added, and a study of the biocompatible Mg-3Ag alloy's cytotoxicity and genotoxicity showed that the alloy is safe for cells. In conclusion, 1/1 (total material concentration) cell viability for QE-30, QZ-30, QX-30, and QZEX3000 was 79.39 ± 1.85, 106.46 ± 1.99, 93.55 ± 2.4, and 141.76 ± 2.71%, respectively. Reducing material concentration by 50% (application at 1/2 concentration) raised viability to 96.83 ± 1.35, 108.40 ± 1.92, 124.71 ± 2.76, and 129.05 ± 3.5%, indicating the as-cast Mg + 3%Ag + 0.5% Nd-Ca-Zn alloy was extremely biocompatible. © 2022, ASM International.

The current study aimed to improve the microstructure and mechanical properties of ZM21 magnesium alloy by using the rolling thermomechanical process at various temperatures (275 and 375 °C) and rates (40 and 60%). The rolled samples' grain size was examined, and it was found that the grain size decreased by 40% during hot deformation, reaching a grain size of 15.91 μm. Surface roughness values were examined and found to be the lowest (parallel and perpendicular to the rolling direction) at a 60% rolling rate in 275 °C and the highest 40% at 375 °C. The highest tensile strength was obtained at a rolling rate of 60% at 375 °C, but it showed brittle fracture during testing. Accordingly, while the 275 °C rolled samples showed ductile fracture behavior, a slight reduction in mechanical properties was observed when the rolling ratio was set at 60%. © 2022, ASM International.

The design and deployment of an e-health monitoring network system are demonstrated in this paper. This system uses smart devices and wireless sensor networks in the real-time study of numerous patient data. Patients can be monitored via telemonitoring with this system, which intends to make diagnosis easier for clinicians. It also makes it easier for doctors and caregivers to keep continuous monitoring of their patients in any critical situations. To monitor the patient's health and surroundings, various medical and environmental sensors were employed, such as temperature, blood pressure, pH level and SPO2 sensors. The measured data have transmitted in real-time through a server/cloud. For privacy and security, the designed architecture of this project was used to keep a closed observation on a home patient case and many patients in health care units or public health hospitals. Furthermore, the readings can also be viewed on the webpage called "ThingSpeak"whereas the webpage is connected to the data cloud and displays the patient's readings via a visualizer in graph real-time form. In conclusion, this system shows a higher efficiency in data measurement and server transmission; thus, it can reduce the service time and expense required. © 2023 Author(s).

Due to its high strength, stiffness, and biocompatibility, titanium alloys are employed in biomedical applications, although their wear resistance is still inadequate. Porous TiNi structures have a lower elastic modulus and density than dense TiNi structures, but they have sufficient shape memory characteristics, making them suitable for power absorption, lightweight, and biomedical implants. This study investigates the porous Ti-Ni Shape memory alloys (SMAs) tribological behavior for sustainable biomaterial's purposes. The ball-on-disk wear approach with a stainless-steel counter ball was conducted at different speeds times and applied loads to reveal the surface degradation of the Ti-Ni SMAs. The experimental procedure was designed via the Taguchi approach as a design of experimental (DoE) model. The wear mechanisms were inspected according to the wear loss, friction temperature, and worn surface feature. The results revealed that the wear rate and ball depth increased as the speed, time, and applied loads increased. However, the friction temperatures fluctuated according to the wear testing parameters due to the same percentage of the surface samples' surface porosity presence. © 2023 Author(s).

In this study, Mg-xAl-3Zn alloys (x=0.5-1-2-3 wt.%) were produced by the permanent mold casting method. Microstructural characterization of alloys was done with the help of optical microscope (OM) and scanning electron microscope with energy-dispersive spectroscopy (SEM/EDS). Dry and bio-corrosive wear behaviors of alloys were investigated comparatively. Depending on the amount of Al in the alloys, the intermetallic phases were differentiated. Mg17Al12 phase was only observed in Mg-3Al-3Zn alloy distributed along the grain boundary as a continuous or semicontinuous network. The Mg-3Al-3Zn alloy hardness value was about 61.60±4.23 HV and approximately 30% higher than the other alloys. Dry wear and bio-corrosive (in simulated body fluid (SBF)) wear performances of the alloys were also compared. The abrasive wear mechanism was evident in dry ambient wear due to the intermetallic phases in the structure. Still, the liquid's lubrication effect is much more dominant in the bio-corrosive wear tests carried out in SBF. While Mg-3Al-3Zn wear rate was the lowest in dry wear, it was determined to be the highest in bio-corrosive wear for all applied load conditions. It had been understood that a large amount of Mg17Al12 phase in the structure caused such a result. © 2021, ASM International.

Titanium alloys have great applications as biomaterials due to their high mechanical strength and density ratio, good corrosion resistance, and biocompatibility. Type β alloys have aroused enormous interest in the development of biomaterials due to their low elastic modulus. This new class of alloys has been formed mainly by adding tantalum, molybdenum, proven not to have biocompatibility. Tantalum is an alloy hardening element, which can increase the mechanical strength of the material. At the same time, molybdenum is a strong β-stabilizer, stabilizing the β phase with 10% quickly. In this work, Ti-15Mo-xTa system alloys were produced by the powder metallurgy method. The result shows the prepared alloy presented the β-phase grain structure, showing more excellent mechanical properties than pure titanium due to hardening in solid solution. © 2022, The Author(s), under exclusive license to Springer Nature Switzerland AG.

The refractory materials used in the wall of the furnaces for glass melting can be prepared from mullite-zirconia composite material. The composite of mullite/zirconia was synthesized from Iraqi kaolin, γ-alumina, and zirconia using thermal decomposition with reaction sintering at 1600 °C. Several batches were prepared with various ratios of kaolin, γ-alumina, and zirconia, and the composite compositions were selected from the Al2O3-SiO2-ZrO2 phase diagram. The mullite-zirconia composite was prepared with different steps beginning with milling the starting materials, semi-dry uniaxial pressing, and then reactive sintering at various temperatures (1200, 1400, and 1600 °C). The predicted phases ZrO2 and Al6Si2O13 were identified by X-ray diffraction patterns according to the phase diagram for all the batches. The lower amount of the zirconia added to mullite reduced porosity and improved the bulk density of the mullite/zirconia composite. The thermal expansion coefficient slightly increased with the addition of zirconia. It also enhanced the thermal shock resistance of the composite. Finally, the mechanical properties were improved by increasing the amount of zirconia particles in a matrix of mullite due to the phase transformation of zirconia from tetragonal to monoclinic phase. © 2021 Associacao Brasileira de Ceramica. All rights reserved.

Resistance spot welding (RSW) of magnesium alloys is very attractive due to not require filler metal. AZ31 Mg alloy sheets were exposed to RSW by constant weld electrode pressure, constant weld times, and numerous weld currents. The potentiodynamic polarization technique was used for the investigation of the corrosion behavior of the alloys. Results showed that the dendritic structure was promoted at the weld zone. AZ31 base metal is more resistant to corrosion than welded alloys. However, when compared with each other, icorr values of the welded alloys decrease as a function of weld current increases. The corrosion rate was predominantly influenced by the distribution of intermetallic and alloying elements, and RSW weld varied, which was in response to altering the joint microstructure. © 2021, The Author(s), under exclusive licence to Springer Nature Switzerland AG part of Springer Nature.

The developing of Composites Metallic Matrix for Aluminum (AMMCs) is one of the leading engineering applications requirements because of the excellent mechanical characteristics low weight with high strength for this metal. This research investigated the impact of ZnO particles on the Compressive strength, Hardness, and Wear characteristics of Al metallic matrix composite manufactured by method stir casting. The strengthening added different weight percent (0, 2, 4, 6, 8 and 10) % ZnO. The microstructure of specimens is the analysis by an optical microscope and determines the compressive strength, hardness, and wear characteristics which increase with an increased weight percentage of ZnO. The increase in the percent of Brinell hardness is (15%), (25%), (35%), (40%), and (50%) for aluminium reinforced with 2, 4, 6, 8, 10 wt. % ZnO particles specimens respectively. Finally, it could be found that the volume loss was drastically reduced by raising the amount of zinc oxide, thus exceeding the composite minimum amount, which represents the total percentage of zinc oxide (10 percent). © 2020 Trans Tech Publications Ltd, Switzerland.

Meso-Macro porous alumina was fabricated using yeast cells as a pore-forming agent. Alumina powder synthesis was achieved by a low cost process (recrystallisation of alum).The effect of the pore forming agent on the true porosity, bulk density and thermal conductivity of porous alumina was characterized. The results show that the true porosity increased with the increasing addition of yeast cells. The bulk density and thermal conductivity at room temperature decreased with the increasing yeast addition. A genetic algorithm method was used to minimize the thermal conductivity of the macro-porous alumina based on the amount of yeast cells used, the sintering temperature, and the hold time. The genetic algorithm found that the best thermal conductivity achievable was equal to 0.152 Watt/m. °C at 20wt% concentration of yeast, a sintering temperature of 1230°C and 1.5 hours of soaking time. The experimental value was 0.14 Watt/m. °C and the slight variance between these values were postulated to be due to experimental error in the measurements. © 2019 The American Ceramic Society

A novel biocomposite material SR/HA/ZnO for maxillofacial prosthetics and jawbone. In this work, hydroxyapatite synthesized by sol-gel technique. Ca(NO3)2·4H2O and (NH4)2HPO4 used as precursors, and nano ZnO was prepared and modify the surface using Oleic acid to get uniform distribution Within the matrix and reduce nanoparticles agglomeration ZnO. Silicone rubber composites were prepared as a second part by using HA as to increase the biocompatibility, mechanical properties of SR, and to get antibacterial nanocomposites ZnO modified were used. The mechanical properties as a property of tensile strength, elastic modulus, elongation, hardness, compressibility, and antibacterial were examined after the addition of HA and ZnO to silicon rubber. The results show the ability to prepare n-ZnO and HA used to enhance the mechanical properties also acts as antimicrobial media for the biocomposite that can be used for prosthetics and jawbone. © Springer Nature Switzerland AG 2020.

A comparative analysis of the thermal conductivity for porous alumina using Taguchi method has been reported in the current research. Porous alumina is one of the most critical ceramics amongst those that are widely used in the thermal insulator industry; this is because of their physical properties. Thus, the investigation of these properties is highly desirable. Test variables were performed for the thermal conductivity studies-weight per cent of a pore-forming agent (yeast), sintering temperature, and soaking time. Through implementing the experimental design using the Taguchi method for thermal conductivity of porous alumina was statistically analyzed. The Signalto- noise ratio and variance analysis investigated the influence of different parameters on the porous media's thermal conductivity. The result of research determines that the addition of the pore-forming agent obtained a higher thermal insulator. Based on the optimum conditions obtained from the Taguchi method factor was 20wt.% weight of yeast cell, sintering temperature at 1200 C, and the holding time 1.5 h. that give higher value of the S/N ratio. © 2020 Trans Tech Publications Ltd, Switzerland.

The pore diameter, type (open or closed), physical properties of Porous alumina ceramic were controlled by varying concentration in the mixture of Polymethylmethacrylate (PMMA) with alumina powder and sintering temperature. The porous alumina ceramic was synthesis by a dry pressing method using a microspheres Polymethylmethacrylate (PMMA) as a pore-forming agent. The properties of the porous alumina were predicted using an experimental approach. Afterwards, the measured data were used to develop a Reduced-order model (Kriging) to enable a fast prediction of the properties for an extended range of parameters variation and further analysis. The experimental results showed that the High porous alumina ceramics is having an open porosity of 72.3%, and a bulk density 1.2 gm/cm3 and these could be fabricated using PMMA microspheres. Kriging model results showed an acceptable prediction of the experimental-derived data with a maximum discrepancy of 0.02% for the apparent porosity. © 2019 Elsevier Ltd. All rights reserved.

In the present study, a recrystallization method was implemented to recover alumina powder from ammonium alum crystal. The ammonium alum was completely dissolved in water and treated by ultra-sonication to prevent the agglomeration of the alum crystal. The white precipitate was dried at 150 °C for 6 h, and calcinations at different temperatures were performed for 2 h. The XRD results indicated the crystalline structure of alumina with two main phases: γ-Al2O3 and α-Al2O3 at 800 and 1200 °C, respectively. The N2 adsorption/desorption isotherm results indicated that the surface area for the powder in the γ phase, which can be applied in catalysts, was 142.5 m2/g, while, in the α-phase, it was 15.3 m2/g. The morphologies elucidated that the powder particles were widely distributed in the range of ≤160 nm at different calcination temperatures and this may be attributed to increments in the particle agglomeration as the calcination temperature increased. © 2019 Associacao Brasileira de Ceramica. All rights reserved.

Porous γ-alumina is widely used as a catalyst carrier due to its chemical properties. These properties are strongly correlated with the physical properties of the material, such as porosity, density, shrinkage, and surface area. This study presents a technique that is less time consuming than other techniques to predict the values of the above-mentioned physical properties of porous -alumina via an artificial neural network (ANN) numerical model. The experimental data that was implemented was determined based on 30 samples that varied in terms of sintering temperature, yeast concentration, and socking time. Of the 30 experimental samples, 25 samples were used for training purposes, while the other five samples were used for the execution of the experimental procedure. The results showed that the prediction and experimental data were in good agreement, and it was concluded that the proposed model is proficient at providing high accuracy estimation data derived from any complex analytical equation. © 2019 by the authors.

The porous gamma alumina Al2O3 has a wide range of many applications, for example, the catalyst carrier. The powder of alumina was prepared from recrystallization of alum and the effect of yeast cell addition as pore forming agent was studied to form porous γ-alumina. The weight percentage of yeast cell added to prepare of porous gamma alumina are (5, 10, 15 and 20%) and the gel casting method was used for preparation of porous gamma alumina. The result showed that the gel-casting method by using yeast cell as pore forming agent is one of the successful method to obtain porous ?-alumina that used as catalyst carrier because the improvement of the amount of porosity with high compressive strength and increase the pore volume and high surface area. The apparent porosity obtained was in the range 12.51-82.25% with compressive strength range from 44.22-7.89 MPa. The porosity increased and decreasing in compressive strength with increasing the percentage ratio of the yeast cell. This result was confirmed by using a regression analysis, R2 was (82.29%) and R-adj was (77.86%). The R2 (94.06%), R-adj (92.58%) according to the regression analysis. © Medwell Journals, 2018.

The modified alumina has been classified as one of the best thermal insulation materials that able to reduce the solar radiation and enhance the working environment and thus, reduce the energy consumption. This paper emphasis the effect of the multi-variables, such as yeast cell ratio, pressing load, sintering temperatures, and socking time on the lower thermal conductivity of the modified alumina. The ceramic thermal insulation was prepared by semi-dry pressing method using alumina with different amount of the bioactive yeast cell as a pore-forming agent and 3 wt.% sugar. The optimization process was carried out via a genetic algorithm for 61 samples according to the chromosome-based. The microstructure results revealed that there are two types of pores were observed; micro and meso size pores. Furthermore, it was also found by depending on the analyzed input data that the thermal conductivity of 2.5× 10-1 watt/m. °C was acquired at the optimal variables of 1200 °C, 19.4 %, 66 MPa, 1.5 hrs. as sintering temperature, yeast cell, pressing load, and socking time, respectively. © 2018 Lavoisier.