Search Results (11,175)

This study presents a computational fluid dynamics (CFD) simulation to investigate fluid flow and heat transfer within the growth zone of gallium nitride crystals synthesized via the alkaline ammonothermal method, with particular emphasis on the influence of seed crystal arrangement and installation geometry. The model analyzes temperature and velocity distributions, highlighting how seed configuration affects turbulent and transitional flow behavior. Key findings demonstrate the effectiveness of CFD in evaluating and optimizing growth zone design. Both simulation and experimental results show that achieving more uniform flow and temperature fields leads to more consistent growth rates and improved structural crystal quality. Furthermore, the study underscores the critical role of installation geometry in shaping flow characteristics such as velocity distribution, temperature gradients, and their transient fluctuations, factors essential for optimizing the ammonothermal crystallization process. Full article

The production of alumina produces red mud (RM), a highly alkaline solid waste. The majority of it is disposed of in landfills, which seriously pollutes the environment. It needs to be recycled and handled with care to protect the environment. RM is a promising raw material for wastewater and waste gas treatment owing to its high alkalinity and abundant metal compounds. It can efficiently remove diverse pollutants while facilitating large-scale utilization of RM resources. Reviews of the use of RM resources to create catalysts for environmental governance are, nevertheless, scarce. Therefore, this paper analyzes and summarizes the pertinent research on RM-based catalysts to remove pollutants from the environment based on journal literature related to RM resource utilization from 2015 to 2025. This study reviews the application of RM-based catalysts for degrading pollutants in wastewater and exhaust gases via advanced oxidation processes (AOPs)—including photocatalysis, Fenton-like catalysis, ozonation catalysis, and persulfate catalysis—as well as catalytic oxidation, chemical looping combustion (CLC), and selective catalytic reduction (SCR). The paper emphasizes the analysis of modification strategies and catalytic mechanisms of RM-based catalysts in environmental remediation and examines the environmental risks and corresponding mitigation measures related to their preparation from RM resources. Finally, it outlines that future research should prioritize green, low-energy modification processes; catalytic systems for the synergistic removal of multiple pollutants; and efficient, recyclable separation and recovery technologies. These directions aim to promote the sustainable application of RM in large-scale environmental remediation and to achieve the integrated advancement of resource utilization and ecological protection. Full article

The vulnerability of copper to corrosion in humid and saline environments remains a critical challenge for its long-term use. In this work, we present a streamlined and scalable approach for fabricating superhydrophobic, corrosion-resistant copper surfaces by integrating a simple wet chemical oxidation process with atmospheric pressure chemical vapor deposition (APCVD) of a perfluorinated silane. The hierarchical CuO nanostructures formed via alkaline oxidation serve as a robust layer, while subsequent silane functionalization imparts low surface energy, resulting in surfaces with water contact angles exceeding 170° and minimal contact angle hysteresis. Comprehensive surface characterization by SEM and roughness analysis confirmed the preservation of hierarchical morphology after coating. Wettability studies reveal a transition from hydrophilic to superhydrophobic behavior, with the Cassie–Baxter regime achieved on nanostructured and silane-functionalized samples, leading to enhanced droplet mobility and self-cleaning effect. Salt spray tests demonstrate that the superhydrophobic surfaces exhibit a corrosion rate reduction of 85.7% (from 2.51 mm/year for bare copper to 0.36 mm/year for the treated surface), indicating a seven-fold improvement in corrosion resistance compared to bare copper. This methodology offers a practical, reproducible route to multifunctional copper surfaces, advancing their potential for use in anti-fouling, self-cleaning, and long-term protective applications. Full article

Steel reinforced grout (SRG) composites are widely used for strengthening existing structures. Galvanized (zinc-coated) ultra-high tensile strength steel cords are more durable than brass-coated and cheaper than stainless-steel ones, making them the most common in practice. While compliant with certification standards, corrosion may occur, potentially affecting tensile strength and bond capacity. The latter has, however, remained largely unexplored, highlighting a need to assess durability under different environmental exposures. This study investigated the durability of galvanized SRGs with four cord types and four mortar matrices (cement- and lime-based). Direct tensile, shear bond, and lap-tensile tests were conducted after immersion in saltwater or alkaline solutions, exposure to freeze–thaw or salt crystallization cycles, and high temperatures. Results highlighted salt exposure as the most critical condition, particularly with lime-based matrices. Zinc coating thickness proved essential for corrosion resistance, while freeze–thaw and salt crystallization led to bond degradation due to concentrated steel corrosion and mortar microcracking. The findings highlight the importance of considering appropriate protective measures and exposure-specific conditions when designing SRG reinforcements. Full article

This study examined the ultrasound pretreatment (UP) and simultaneous ultrasound (US) effects on the structural–functional features of collagen peptides in Chinemys reevesii skin collagen hydrolysates (CCHs) using a composite protease system (Trypsin: Alkaline protease, 1:1). Structural characterization revealed that UP induced the unfolding of collagen molecules, evidenced by reduced disulfide bond content and the concomitant increase in surface hydrophobicity. Consequently, ultrasound pretreatment-assisted enzymatic hydrolysis (UPH) significantly enhanced the yield of low-molecular-weight components (<0.18 kDa) and hydrophobic amino acids, which rose by 3.03% and 4.89% compared to the results of conventional enzymatic treatment (CE). UPH showed higher antioxidant activity than CE and WUH over CE and whole-process ultrasound-assisted hydrolysates (WUH). At 5 mg/mL, it displayed an ABTS radical scavenging rate of 87.59%, a DPPH scavenging rate of 53.37%, and the highest reducing power. However, WUH induced peptide reaggregation due to prolonged ultrasonication, thus exhibiting moderately lower antioxidant activity than UPH. These findings suggest that UP is an effective strategy to optimize the structure and composition of CCHs, outperforming both CE and WUH in facilitating the release of antioxidant peptides and improving antioxidant capacity. Full article

This article presents a technology for the production of magnesium hydroxide from serpentinite via sulfuric acid leaching of magnesium and purification of the resulting sulfate solution from impurity metals using thermally activated serpentinite (TA-SP) at 750 °C for one hour. Purifying the leach solution is one of the key challenges in obtaining high-purity magnesium compounds from serpentinite. It has been established that the use of thermally activated serpentinite to neutralize the acidic suspension of serpentinite to pH 8.3, prior to treatment with an alkaline agent (sodium hydroxide), has a positive effect on the purity of the precipitated magnesium hydroxide. The influence of the thermal treatment on the acid–base properties of serpentinite, its phase composition, and adsorbent structure parameters, such as specific surface area and micropore distribution, was studied, revealing improvements in the adsorption properties. Flowcharts for the acid leaching and magnesium hydroxide precipitation processes are provided. The flow-sheet that we propose is shown to reduce the number of steps in the process and amount of equipment required for the purification of sulfate solution while ensuring that the magnesium hydroxide product has a purity of at least 99.5%. Full article

A series of metal–organic framework-based materials of the MIL-101 family was prepared for potential application as anodic electrocatalysts in the direct borohydride fuel cell. The MIL-101-based materials were tested for borohydride oxidation reaction using cyclic voltammetry and chronoamperometry in alkaline media, with Au@MIL-101-NH₂ showing high responsiveness. The obtained data allow for the determination of kinetic parameters that characterize the borohydride oxidation on the prepared electrocatalysts. The activation energy for borohydride oxidation using an Au@MIL-101-NH₂ electrocatalyst was as low as 13.6 kJ mol⁻¹ with a reaction order of 0.4. The anodic charge transfer coefficient was 0.85, and the number of transferred electrons was 7.97, matching the theoretical maximum value of 8 electrons transferred during the borohydride oxidation reaction. The promising performance of Au@MIL-101-NH₂ suggests its potential application as an anode for direct borohydride fuel cells. Full article

This research investigates the glycerol oxidation reaction on carbon-functionalized composites using Tafel behavior, exchange current density (ECD), rate constant, and dynamic electrochemical impedance spectroscopy (DEIS) data fitting. The aim is to gather essential data for fabricating glycerol electrooxidation electrodes in an alkaline medium. Corrected net current analysis reveals that the nitrogen-doped activated carbon black composite electrode (ACB-N2) exhibits the highest instantaneous catalytic activity, with a net current density of 1.3 mA cm⁻² at 1.0 V vs. SCE. However, the dual-doped nitrogen and fluorine composite (ACB-N2F2) demonstrates the lowest Tafel slope (177.97 mV dec⁻¹), indicating faster kinetics, and it maintains superior electrochemical stability during chronoamperometric testing. ACB-N2F2 exhibits the highest ECD (1.0129 mA cm⁻²) and the lowest Ts and rate constant (2.62 × 10⁹ cm s⁻¹), indicating the fastest electron transfer. These findings suggest that while ACB-N2 offers the highest net GOR activity, ACB-N2F2 combines kinetic efficiency and long-term durability, making it a promising candidate for practical GOR applications. The rate-determining step is water adsorption at low overpotentials (0.55 V, 0.5 V, and 0.4 V vs. SCE for ACB-F2, ACB-N2, and ACB-N2F2, respectively). Full article

Efficient and selective separation of gallium (Ga(III)) from alkaline industrial waste streams remains a significant challenge due to the coexistence of chemically similar ions such as Al(III) and V(V). In this study, a novel ion-imprinted chitosan-based adsorbent (CS/(H-CGCS)-Ga-IIP) was synthesized via a hybrid cross-linking strategy using glutaraldehyde and siloxane-modified chitosan. The optimized material exhibited a high adsorption capacity of 106.31 mg·g⁻¹ for Ga(III) at pH 9, with fast adsorption kinetics reaching equilibrium within 60 min. Adsorption behavior followed the pseudo-second-order kinetic and Langmuir isotherm models, and thermodynamic analysis indicated a spontaneous and endothermic process. In simulated Bayer mother liquor systems, the material demonstrated outstanding selectivity and a distribution coefficient ratio k_d-Ga/k_d-Al = 146.9, highlighting its strong discrimination ability toward Ga(III). Mechanistic insights from SEM-EDS, FTIR, and XPS analyses revealed that Ga(III) adsorption occurs via electrostatic interaction, ligand coordination, and structural stabilization by the siloxane network. The material maintained good adsorption performance over three regeneration cycles, indicating potential for reuse. These findings suggest that CS/(H-CGCS)-Ga-IIP is a promising candidate for the sustainable recovery of gallium from complex alkaline waste streams such as Bayer process residues. Full article

Syngenetic fluid inclusions in natural diamonds are indicators of the composition of fluids responsible for growth and crystallization conditions. The chloride concentration in saline fluid inclusions of natural diamonds reaches 50 wt%. We study the dissolution of diamonds in the H₂O-KCl-NaCl system at temperatures of 1200 °C and 1400 °C and a pressure of 5.5 GPa using a BARS high-pressure multi-anvil apparatus. Two scenarios of diamond dissolution were experimentally investigated: (i) metasomatism by saline brines at high oxygen fugacity of the magnetite–hematite buffer; (ii) interaction with reduced carbon-unsaturated water–chloride fluid at low fO₂ imposed by the iron–wüstite buffer. It is found that the presence of alkaline chlorides in the aqueous fluid significantly accelerates diamond dissolution at high oxygen fugacity but inhibits the process under reduced conditions. The morphology of diamond dissolution features is controlled by the presence of water in the fluid over the entire range of the studied P-T-fO₂ conditions. Experimental results indicate that the interaction with oxidizing highly saline fluids during metasomatic events could negatively affect diamond preservation in mantle rocks and eventually lead to the formation of uneconomic kimberlites. Under reducing conditions, water–chloride fluids favor diamond preservation. Full article

Polyamines (PAs), including putrescine, spermidine, spermine, and thermospermine, play essential roles in plant growth, development, and responses to stress. However, the structure and function of PA biosynthetic genes in pepper remain poorly characterized. This study aimed to identify PA biosynthesis genes in the pepper genome using bioinformatics approaches and to assess their expression under various stress conditions. A total of 16 PA biosynthesis-related genes were identified, representing members of the arginine decarboxylase (ADC), ornithine decarboxylase (ODC), agmatine iminohydrolase (AIH), N-carbamoylputrescine amidohydrolase (CPA), S-adenosylmethionine decarboxylase (SAMDC), spermidine synthase (SPDS), spermine synthase (SPMS), and ACAULIS5 (ACL5) gene families. These genes encode proteins with an average molecular weight of approximately 40 kDa, primarily localized in the mitochondria and cytoplasm. Promoter analysis revealed multiple cis-acting elements associated with stress and phytohormone responsiveness. Gene expression was induced by various abiotic stresses, including saline-alkaline, drought, heat, cold, and hydrogen peroxide, as well as by phytohormones such as abscisic acid, ethylene, salicylic acid, auxin, and gibberellin. Overall, this study provides a comprehensive analysis of PA biosynthesis genes in pepper and highlights their potential roles in stress adaptation and hormone signalling, offering a foundation for further exploration of PA-mediated stress tolerance mechanisms. Full article

Objectives: We investigated the relationship between bone metabolic markers or bone mineral density (BMD) and sarcopenia in patients with type 2 diabetes mellitus (T2DM). Methods: In this cross-sectional study involving 119 subjects (76 women and 43 men), bone metabolic markers were evaluated by bone alkaline phosphatase and bone tartrate-resistant acid phosphatase (TRACP-5b). BMD was measured using the dual-energy X-ray absorptiometry method, and sarcopenia was diagnosed using skeletal muscle mass index (SMI), evaluated by body composition measurement and handgrip strength. Results: Significant correlation was observed between handgrip strength or SMI and TRACP-5b in both sexes (correlation coefficients were −0.50 in handgrip strength and −0.41 in SMI in men; −0.25 in handgrip strength and −0.21 in SMI in women). Furthermore, significant correlation was observed between handgrip strength or SMI and BMD of the femoral neck in both sexes (correlation coefficients were 0.33 in handgrip strength and 0.44 in SMI in men; 0.34 in handgrip strength and 0.47 in SMI in women). The concentrations of TRACP-5b with sarcopenia were significantly higher than those without (643.8 ± 261.9 vs. 455.7 ± 165.6 mU/dL), and BMD of femoral neck with sarcopenia was significantly lower than those without (0.54 ± 0.12 vs. 0.66 ± 0.16 g/cm²). TRACP-5b (odds ratio 1.05, 95% confidence interval 1.01–1.10) and femoral neck BMD (odds ratio 0.30, 95% confidence interval 0.14–0.68) were associated with the presence of sarcopenia after adjustment for confounders. Conclusions: TRACP-5b and BMD of the femoral neck were associated with sarcopenia in patients with T2DM. Full article

A package of upper Messinian volcaniclastic layers (UMVLs), exposed in the deep-water foreland basin system of the central Apennines (Italy), is the volcanic product of a rhyolitic eruption dated to 5.5 Ma. These UMVLs are an important marker for stratigraphic correlations along the central Apennines foreland basin system, but their source is still debated and poorly understood. Italian Plio-Quaternary volcanism exhibits significant petrological and geochemical variability, causing debate over magma genesis and differentiation. Investigating the magmatic evolution of central Italy is crucial for understanding one of the most complex geodynamic settings on Earth. The first evidence of efficient magma differentiation, producing eruptible calc-alkaline rhyolitic magmas, is the San Vincenzo eruption at 4.41 Ma. Our sedimentological and petrological analyses of UMVL exposures indicate a possible volcanic source in the northeastern Tuscany Magmatic Province. This discovery implies a developed transcrustal magma reservoir system and suggests that efficient magma differentiation capable of producing eruptible calc-alkaline rhyolitic magma occurred about one million years earlier than the San Vincenzo eruption, marking these UMVLs as the first rhyolitic eruption associated with Italian Plio-Quaternary volcanism. Full article

Saline–alkaline water resources are globally widespread, and their rational development offers significant potential to alleviate freshwater scarcity. Saline–alkaline water aquaculture farming not only affects fish growth and survival but also impairs reproductive and developmental functions. Largemouth bass (Micropterus salmoides), an economically important fish, has demonstrated excellent high tolerance to such environments, in order to investigate the effects of alkaline water aquaculture environments on its growth performance, sex hormone levels, gonadal development, and molecular adaptation mechanisms. In this study, largemouth bass were chronically exposed to freshwater (0.55 mmol/L), low alkalinity (10 mmol/L), or high alkalinity (25 mmol/L) and cultured for 80 days. Alkalinity exposure more severely impacted the growth rate of females. High alkalinity significantly increased the hepatosomatic index and decreased the gonadosomatic index in both sexes; moreover, it induced oxidative stress in both sexes, evidenced by reduced superoxide dismutase (SOD), catalase (CAT), and total antioxidant capacity (TAOC) levels and elevated malondialdehyde (MDA) content. Furthermore, the levels of sex hormones Serum estradiol (E2), 11-ketotestosterone (11-KT), and testosterone were significantly reduced, accompanied by either an elevated ratio of primary oocytes and follicular atresia, or by reduced spermatogenesis. Apoptotic signals appeared in gonadal interstitial cells, with upregulated expression of genes P53, Bax, Casp3, and Casp8. Ultrastructural damage included fewer mitochondria and cristae blurring, further indicating tissue damage causing dysfunction. Transcriptome results showed that oxidative stress damage and energy metabolism imbalance caused by carbonate alkalinity were key to the delayed gonadal development, which was mainly manifested in enrichment of the ECM–receptor interaction and PI3K-Akt signaling pathways in females exposed to low alkalinity, and the GnRH secretion and chemokine signaling pathways in males. Glycosphingolipid biosynthesis and Ferroptosis pathway were enriched in females exposed to high alkalinity, and the Cortisol synthesis and secretion pathway were enriched in males. Overall, high-alkalinity exposure significantly delayed gonadal development in both sexes of largemouth bass, leading to reproductive impairment. Full article

Grape pomace (GP), a polyphenol-rich byproduct of winemaking, holds considerable health benefits and potential as an antibiotic alternative for livestock animals. However, its utilization is compromised by the contamination of mycotoxins produced by pathogenic molds (with ochratoxin A (OTA) being the most frequently detected), which pose hidden health risks to both livestock animals and human beings. This study evaluated the efficacy of thermal–pressure treatment (pressure cooking) with and without the addition of acidic and alkaline agents, and the combined thermal-pressure and fermentation with four lactic acid bacteria (LAB) strains, including Lactobacillus bulgaricus (LB6), Lacticaseibacillus paracasei (previously Lactobacillus paracasei) (BAA-52), Lactobacillus acidophilus, and Lactiplantibacillus plantarum (previously Lactobacillus plantarum), on reducing OTA and preserving polyphenols in GP. The study found that pressure cooking alone reduced OTA by approximately 33–35% in 30–45 min. The addition of citric acid (CA) or acetic acid (AA) enhanced OTA reduction to 46.9–55.2% and 51.7–54%, respectively, while preserving more polyphenols, notably anthocyanins. Conversely, pressure cooking with the addition of NaHCO₃ facilitated greater OTA reductions (40.4–63%), but concomitantly resulted in substantial polyphenol loss, especially anthocyanins. Fermentation for 24 h with LAB following thermal–pressure treatment resulted in up to 97% OTA reduction for Lc. paracasei, L. acidophilus, and Lp. plantarum strains, which displayed similar high effectiveness in OTA reduction in GP. L. bulgaricus (LB6) was least effective (45%), even after 72 h of fermentation. These findings indicate that home-scale pressure cooking combined with lactic acid fermentation effectively detoxifies OTA-contaminated GP, thus enhancing its safety profile for consumption by livestock animals and humans, despite partial polyphenolic losses. Full article