Search Results (2,568)

22Cr12NiMoWV martensitic heat-resistant steel serves as a candidate material for underground coiler sector plates, whereas the coupling relationship between partial austenitization, precipitate/carbide evolution, martensitic interfaces and mechanical response under medium-temperature quenching–tempering conditions is still ambiguous. This work systematically explores four key heat treatment variables to clarify the microstructure–property correlation and strengthening rebalance mechanism. In the 790–830 °C partial austenitization interval, the austenite fraction increases from 36.49 wt.% to 72.32 wt.% with a concurrent decline of M₂₃C₆ carbides from 5.34 wt.% to 4.92 wt.%, demonstrating competitive evolution between austenite generation and carbide retention. Specimens quenched at 810 °C for 2 h deliver a yield strength of 1015.4 ± 13.8 MPa and tensile strength of 1192.9 ± 17.8 MPa, 24.9% and 19.9% higher than conventional QT samples, owing to synergistic reinforcement from α′ martensite matrix, orientation interfaces and Cr-Mo-W-V-rich precipitates. After 400 °C × 4 h tempering, the steel still maintains superior strength, and its average misorientation falls from 40.41° to 31.17°. Though its engineering ductility is inferior to the quenched state, the mixed dimple–quasi-cleavage fracture mode suggests a partial recovery of ductile fracture characteristics compared with over-treated samples. The uncovered strengthening mechanism provides microstructural theoretical support for process optimization. Compared with the conventional quenching and tempering process, the optimized medium-temperature process (810 °C × 2 h quenching + 400 °C × 4 h tempering) reduces energy consumption and the production cycle and provides solid theoretical and experimental data for a green and low-cost industrial heat treatment of coil plates. Full article

Electrocatalytic glycerol oxidation to formic acid (FA) offers a sustainable route for biomass valorization, yet non-noble metal catalysts generally suffer from sluggish C-C bond cleavage and poor product selectivity. Here we report an amorphous nickel–cobalt oxyhydroxide bearing both metal and oxygen vacancies (D-NiCoO_xH_y-V_Cr,O), grown on nickel foam via one-step electrodeposition followed by electrochemical activation with Cr doping. The coexistence of the dual vacancies is experimentally confirmed by X-ray photoelectron spectroscopy (XPS), which reveals elevated Ni³⁺/Co³⁺ ratios and reduced lattice oxygen, and by electron paramagnetic resonance (EPR), which shows a markedly enhanced signal at g = 2.003. Building on prior Cr-leaching approaches in single-metal nickel oxides, this work extends dual-vacancy engineering to an amorphous bimetallic NiCo oxyhydroxide and correlates the defect structure with glycerol-induced interfacial responses, charge-transfer behavior, and product selectivity. The catalyst delivers 200 mA cm⁻² at 1.31 V vs. RHE and achieves 100% Faradaic efficiency for formate at 1.32 V vs. RHE. In situ electrochemical impedance spectroscopy further reveals a significantly reduced charge-transfer resistance. These results establish Cr-assisted dual-vacancy engineering in amorphous bimetallic oxyhydroxides as a promising strategy for selective biomass electrooxidation. Full article

Trace element contamination represents a persistent environmental issue, particularly in industrialized areas where anthropogenic emissions overlap with natural geochemical backgrounds. This study investigates the atmospheric deposition of trace elements in the Milazzo district (Italy), which is characterized by intense industrial activity. Pinus pinea L. needles were used as biomonitors to assess the spatial distribution and sources of trace elements, combined with lead isotopic analysis for source apportionment. Forty needle samples were analyzed by ICP-OES and ICP-MS for Ca, K, Mg, Na, P, Al, As, Ba, Cd, Co, Cr, Cu, Fe, Mn, Mo, Ni, Pb, Sb, Ti, V, Zn, Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu, while 25 samples were selected for Pb isotope ratio determination (²⁰⁶Pb/²⁰⁷Pb and ²⁰⁸Pb/²⁰⁶Pb). Multivariate statistical analyses identified source groups related to industrial and petrochemical emissions, vehicular traffic, crustal resuspension, and mixed combustion processes. Elevated concentrations of As, Cr, Mo, Ni, Pb, Sb, V, and Zn ranged from 16.6 μg g⁻¹ (Zn) to 0.09 μg g⁻¹ (Sb), with the following order of abundance: Zn > Cr > Ni > Pb > Mo > V > As > Sb; these elements were found near industrial facilities and urban areas. Enrichment Factor calculations indicated strong anthropogenic contributions to Cd, Cu, Mo, Sb, V, and Zn, with EF > 10, ranging from 10 (Cd) to 60 (Zn), whereas Al, Fe, and Ti exhibited EF values between 0.5 and 2, reflecting geogenic origins. Pb isotopic ratios (²⁰⁶Pb/²⁰⁷Pb = 1.153–1.192 and ²⁰⁸Pb/²⁰⁶Pb = 2.063–2.108) revealed mixing between industrial emissions and the local geological background, with limited influence from historical gasoline-derived Pb. This integrated geochemical and isotopic approach can effectively identify contamination sources in complex industrial environments. Full article

Ag-Ti₃SiC₂ composites are promising electrical contact materials, yet the atomic-scale interfacial behaviour between Ti₃SiC₂ and Ag remains poorly understood. Here, first-principles calculations were performed to investigate the interfacial stability, electronic structure, and alloying effects at the Ti₃SiC₂(0001)/Ag(111) interface. Surface-energy calculations for six terminations of Ti₃SiC₂(0001) show that the TiC(TiC) termination is preferred at low carbon chemical potential, whereas the TiC(TiSi) termination becomes the most stable once ΔμC exceeds −1.50 eV. Eighteen interface models combining the six terminations with three stacking sequences (OT, MT, and HCP) were constructed, and their work of adhesion (Wad) and equilibrium spacing (d₀) were determined by the Universal Binding Energy Relation and full structural relaxation. The HCP stacking is preferred for all terminations, and the C(TiC)-terminated HCP interface exhibits the highest work of adhesion among all configurations, with Wad = 9.25 J/m² at d₀ = 1.2 Å; relaxation enhances Wad by 10%–75%. Charge density, charge density difference, and partial density of states analyses reveal that the interfacial bonding is dominated by C 2p-Ag 4d hybridization accompanied by electron transfer from Ag and Ti atoms to the interfacial C atoms, which accounts for the adhesion hierarchy. Substitutional alloying with Cu, Ni, Zn, and Cr preferentially segregates into the interfacial Ag layer, where the defect formation energies, although positive, are the lowest, and Wad increases in the order Cu < Zn < Ni < Cr, reaching 11.0 J/m² for interfacial Cr, an enhancement of 19% over the pristine interface. The strengthening correlates directly with the filling of the dopant 3d band. These results provide theoretical guidance for the interfacial design of high-performance Ag-Ti₃SiC₂ electrical contact composites. Full article

The surface of nodular cast iron is susceptible to wear failure under high-load conditions. In this study, Fe-Cr-Ni wear-resistant coatings were developed on the surface of nodular cast iron using laser cladding technology. The influence of laser power (P), powder feeding rate (F), scanning speed (V), and overlapping rate (φ) on the microhardness and dilution rate of the coatings was analyzed by response surface methodology, while the model’s accuracy was evaluated through analysis of variance. Subsequently, the multi-objective particle swarm optimization algorithm was utilized to identify the optimal process parameters (P = 1350 W, V = 12.5 mm/s, F = 9 g/min, and φ = 45%) based on non-destructive testing results. The predictive model values closely matched the experimental results. The average microhardness of the Fe-Cr-Ni cladding layer was 620.3 HV, which was 2.8 times that of the nodular cast iron substrate. Importantly, the laser cladding layer demonstrated a significant improvement in wear resistance compared to the substrate. The wear mechanisms for the coating predominantly involved mild abrasive wear and adhesive wear, while the substrate primarily experienced severe adhesive wear. This study offers valuable insights for optimizing laser cladding process parameters for nodular cast iron. Full article

The development of sustainable and low-cost electrocatalysts based on Earth-abundant elements is essential for the large-scale deployment of green hydrogen production via anion exchange membrane water electrolysis (AEMWE). Herein, we demonstrate the feasibility of cobalt-free high-entropy oxide (HEO) electrodes for AEMWE through a set of spinel oxides based on equimolar Cr, Mn, Fe, Ni, and Zn. The HEOs were synthesized by a scalable sol-gel route followed by calcination at different temperatures (400–800 °C). The pristine oxides were employed as oxygen evolution reaction catalysts, whereas their H₂/Ar-reduced counterparts were used as hydrogen evolution reaction catalysts in symmetric membrane electrode assemblies (MEAs). Comprehensive physicochemical characterization combined with electrochemical testing revealed that the phase purity of the anodic catalyst mainly correlates with both the maximum current density and the polarization resistance of the electrolyzer. In contrast, a correlation is observed between the physicochemical features of the reduced cathodic catalyst, the iR-free potential and the polarization resistance after prolonged operation. The best-performing Co-free MEA achieved a current density of 0.51 A cm⁻² at 2.2 V and exhibited stable operation for hundreds of hours under alkaline electrolysis conditions. Although the complete replacement of cobalt results in lower activity than previously reported Co-containing HEOs, the present work establishes a viable design strategy for fully Co-free electrocatalysts and highlights the critical balance between catalytic performance, long-term stability, and material sustainability in future AEMWE technologies. Full article

Pulsed Electric Fields (PEF) offer significant potential to enhance energy efficiency and reduce reliance on SO₂ and other chemical preservatives, aligning with current sustainability and health demands. This work evaluates PEF industrial viability for wine stabilisation through a multidisciplinary pilot-scale approach (108 L/h). A sulfur-free comparative trial evaluated four sequential bipolar PEF treatments (20–23 kV/cm; 19–34 kJ/kg) against stabilisation with a commercial chitosan–glucan complex. PEF caused significant effects on microbial kinetics: B. bruxellensis was successfully maintained below the detection limit and lactic acid bacteria (LAB) were undetected by the end of the trial. Standard oenological parameters showed no relevant changes, except for lactic acid dynamics, corroborating LAB knockdown. Regarding metal ion migration into the food matrix, Fe, Ni, and Cr were assessed. No significant variations were found for Fe and Ni compared to the control group; all elements presented residual concentrations compatible with international regulatory guidelines. Sensory analysis revealed that PEF-treated wines exhibited lower perceived bitterness and higher colour intensity, driven by B. bruxellensis proliferation in control wines. In total, 75% of panellists preferred PEF wines. OPEX analysis demonstrates industrial competitiveness for medium-to-large scale, reducing consumable costs over 10-fold (0.6064 vs. 6.50 €/hL), excluding initial CAPEX. These findings validate multi-stage, pilot-scale PEF as a competitive and electrochemically safe technology to transition toward sustainable reduced-SO₂ or SO₂-free winemaking. Full article

The high mortality associated with largemouth bass ranavirus (LMBRaV) disease requires rapid and sensitive diagnosis methods to prevent virus spread and subsequent outbreak. The recombinase polymerase amplification combined with the CRISPR/Cas12a system (RPA-CRISPR/Cas12a) assay and RPA-CRISPR/Cas12a, coupled with lateral flow dipstick (RPA-CRISPR/Cas12a-LFD) assay for LMBRaV, were established in this study for low viral load surveillance. The major capsid protein (mcp) gene is highly conserved and is widely used as the target sequence in LMBRaV detection. First, based on the mcp gene sequence of LMBRaV, three candidate crRNAs were designed. Among them, the crRNA-2, which exhibited the highest cleavage activity, was selected through dual evaluation of fluorescence signal intensity and LFD color development. Then, the key reaction conditions for both assays were optimized as follows: LbCas12a protein concentration of 150 nM, crRNA-2 concentration of 200 nM, and ssDNA reporters’ concentration of 200 nM. Moreover, specificity evaluation showed that both combined assays specifically recognized LMBRaV, with no cross-reactivity detected against other aquatic pathogens, such as CyHV-2, GSIV, ISKNV, WSSV, GCRV II or CrERV. The detection limit was 1 copy/μL of DNA sample for both RPA-CRISPR/Cas12a and RPA-CRISPR/Cas12a-LFD assays. Finally, validation using 24 clinical samples (16 positive, eight negative) showed that both LMBRaV RPA-CRISPR/Cas12a assays achieved 100% detection rate, whereas conventional PCR detected 13 positive samples (detection rate 81.26%). ddPCR served as the reference method for clinical validation. Therefore, the LMBRaV RPA-CRISPR/Cas12a assay and the RPA-CRISPR/Cas12a-LFD assay provide sensitive, specific, and easy-to-operate methods for the rapid detection of LMBRaV. Full article

Agricultural soils in arid regions require assessment approaches that separate local element enrichment from actual ecological and human health relevance. Here, a site-prioritization framework is applied to potentially toxic elements (PTEs) in agricultural soils from Onaizah, central Saudi Arabia. The approach combines contamination indices, ecological-risk screening, deterministic health-risk estimates, Monte Carlo resampling, and relative ranking of management priorities. A total of 33 surface-soil samples collected from cultivated farms were examined for As, Co, Cr, Cu, Mn, Ni, Pb, V, and Zn. The measured concentration ranges (mg/kg) were 1–5 (As), 1–12 (Co), 10–53 (Cr), 4–38 (Cu), 107–541 (Mn), 6–54 (Ni), 2–23 (Pb), 8–47 (V), and 11–168 (Zn). Based on their mean concentrations, the investigated elements decreased in the following sequence: Mn > Zn > Cr > Ni > V > Cu > Pb > Co > As. The P_N values ranged from 0.127 to 1.339, indicating 27 safe sites, 2 warning-line sites, and 4 slightly polluted sites, mainly controlled by localized Zn enrichment and, in one case, Pb. In contrast, mCd values of 0.099–0.676 indicated nil to very low contamination, while RI values of 2.743–15.701 confirmed low ecological risk across all samples. Non-carcinogenic risk was generally below the threshold of concern, with HI values of 0.204–1.018 for children and 0.024–0.119 for adults. Only one site showed a marginal child HI exceedance, emphasizing localized rather than widespread health concern. Children showed approximately 8.6-fold higher non-carcinogenic risk than adults, with Mn, Cr, As, and V as the main contributors. The total LCR values for As, Cr, and Pb ranged from 7.79 × 10⁻⁶ to 4.07 × 10⁻⁵ for children and from 3.48 × 10⁻⁶ to 1.82 × 10⁻⁵ for adults, within the commonly tolerable range of 1 × 10⁻⁶ to 1 × 10⁻⁴. Chromium was the dominant contributor to LCR. Monte Carlo resampling supported the deterministic risk classification, with only a 3.1% probability of child HI exceeding 1 and no simulated exceedance of the LCR threshold for either children or adults. From the standpoint of sustainable soil management, site 7 should undergo further health-risk assessment, while sites 30 and 33 require source verification and periodic monitoring before any remediation action is considered. Full article

The aim of this study is to determine the age and depositional environment of the Harami Formation through an integrated interpretation of XRF, ICP-MS, SEM-EDS, stable isotope, and radioactive isotope analysis results and findings of larger benthic foraminifera. Findings from the authors’ previous studies regarding the characteristics of larger benthic foraminifera were utilized; geochemical analysis results were obtained for the first time in this study. The mean ⁸⁷Sr/⁸⁶Sr values are generally consistent with the ages determined from the larger benthic foraminifera. The analysis results and Y/Ho values indicate that CaO is the dominant component, while negative Ce and positive Eu anomalies are indicative of a low-grade diagenetic effect. The absence of hydrothermal activity in the depositional environment and the proximity of the values to those of seawater are supported by the Y/Ho and Eu/Sm ratios. Similarly, to the larger benthic foraminifera content that indicates the Harami Formation was deposited in a shallow, oxic environment, the trace element ratios (V/Cr and V/V+Ni) and slightly negative Ce anomalies also support deposition in an oxic environment, while the Sr/Ba and Sr/Rb analysis results indicate a shallow marine environment. The analysis results further indicate that the depositional environment ranged from warm-temperate to arid conditions. A decrease in mean temperature is observed from the late Campanian to the early Maastrichtian, with an increase from the early Maastrichtian to the late Maastrichtian. Full article

Efficient and sustainable isolation of cellulose from sugarcane tops (ST), a major sub-fraction of sugarcane trash, is of great significance for the high-value valorization of cellulose and its subsequent conversion into substrates for biomaterials. This study introduces a novel two-step cascade process under mild conditions, which integrates two treatments: a green multi-functional depolymerizing agent (MDA) treatment and the alkaline hydrogen peroxide (AHP) treatment. This sequential strategy is designed to selectively solubilize hemicellulose and lignin, respectively, ultimately yielding cellulose from ST. To assess extraction efficacy, four MDA treatment durations (0–3 h) were systematically investigated. The quality of the extracted cellulose was evaluated through lignocellulosic composition analysis, surface morphology, X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), and thermogravimetric analysis (TGA). Results demonstrate that the MDA treatment effectively disrupted ST’s recalcitrant structure, facilitating selective hemicellulose enrichment in deionized water and lignin dissolution in 1% (w/v) AHP. Notably, cellulose pretreated for 2 h exhibited preferred properties, including high purity (85.82%), a retention rate of 85.33%, preservation of the cellulose I crystalline polymorph (crystallinity index, CrI = 69.11%), and excellent thermal stability (maximum decomposition temperature, Tmax = 344.48 °C). The preserved structural integrity suggests the potential suitability of the extracted cellulose as a promising feedstock for polymer composite applications. Full article

This study provides baseline information for environmental assessment in North Riyadh, Saudi Arabia. It assessed the concentrations of eight heavy metals, namely cobalt (Co), chromium (Cr), copper (Cu), iron (Fe), nickel (Ni), lead (Pb), vanadium (V), and zinc (Zn), in 28 surface soil samples collected across the area. Pollution status was evaluated using the contamination factor (CF), geoaccumulation index (Igeo), enrichment factor (EF), pollution load index (PLI), and degree of contamination (DC), while Pearson correlation, principal component analysis (PCA), and standardized hierarchical cluster analysis (HCA) were applied to identify the possible sources of these metals. Iron was the most abundant element (mean 8482.14 mg kg⁻¹), consistent with its role as a major crustal constituent. Co, Cr, Fe, Ni, and V showed low contamination (CF < 1) and a predominantly geogenic origin, reflected in strong inter-element correlations and a dominant rotated principal component explaining 54.8% of the total variance; Cu, Pb, and, in particular, Zn departed from this pattern, loading together on a distinct secondary component (32.1% of variance) and showing localized enrichment at a small number of sites. None of the 28 samples exceeded the pollution threshold for PLI (all < 1) or DC (all < 8), indicating that the soils of North Riyadh remain overall unpolluted with respect to these eight metals. These findings provide an early geochemical baseline for the district and identify Cu–Pb–Zn enrichment near construction and traffic corridors. Full article

The ultra-large steam turbine rotor and heavy gas turbine disk are key components of power stations. They are manufactured from very large ingots, and extremely low strain rates are used during forging. In this study, a high-strength CrNiMoV steel, 25Cr1Ni4MoV, was hot-compressed at 1000–1200 °C and strain rates of 0.01–0.0001 s⁻¹, and the resulting deformed microstructures were observed. The peak stress ranged from 17 to 72 MPa. The hot deformation equation was obtained, and the activation energy for deformation was determined to be 329 kJ/mol, which was lower than that reported in previous studies due to the extremely low strain rate. The deformation mechanism is dynamic recrystallization even at a strain rate of 0.0001 s⁻¹. The critical strains for complete dynamic recrystallization were determined. The dynamic recrystallization grain size increased slowly with decreasing ln(Z), where Z is the Zener–Hollomon parameter, within the ln(Z) range of 22–27. However, when ln(Z) was below 21, the dynamic recrystallization grain size increased rapidly. This critical ln(Z) value is a new finding. Strategies for controlling grain size in the production of ultra-large steam turbine rotors and heavy gas turbine disk forgings were provided. Finally, future research directions were discussed. Full article

Heavy metal wastewater, characterized by high toxicity, poor biodegradability, and strong bioaccumulation potential, poses a serious threat to the ecological environment and human health. Conventional chemical treatment methods are costly and prone to secondary pollution. In contrast, using solid waste to prepare environmental functional materials for “waste control by waste” has emerged as a research hotspot in the field of synergistic water pollution control and resource recovery. This review systematically consolidates the sources, physicochemical properties, and compositional characteristics of typical industrial solid wastes—including red mud, electroplating sludge, fly ash, copper slag, and blast furnace slag—and elucidates how compositional variations constrain the selection of functionalization pathways. On this basis, key preparation techniques, namely hydrothermal synthesis, surface modification/impregnation, thermal treatment, geopolymerization, and sol–gel/polymerization, are critically reviewed and compared in terms of product structural regulation, process complexity, and engineering scale-up potential. Subsequently, the adsorption performance of the resultant materials toward heavy metals such as Pb²⁺, Cu²⁺, Cr(VI), As(VI), Cd²⁺, Ni^2+, and Zn²⁺ is discussed, with particular emphasis on the pronounced effects of pH, temperature, initial concentration, coexisting ions, and adsorbent dosage on adsorption capacity. Notably, Pb²⁺ exhibits the highest adsorption capacity, whereas the removal of Cr(VI) and As(V) is strongly governed by the positive charge density and reduction efficiency of the material surface. In quinary heavy metal competitive systems, marked differences in the affinity of adsorption sites toward distinct metal ions have been observed. Mechanistic analysis identifies ion exchange, surface complexation, electrostatic attraction, and redox reactions as the predominant removal pathways. This review further incorporates engineering-oriented assessments, including multi-component competitive adsorption, fixed-bed column operation, and regeneration stability, and identifies the critical bottlenecks currently impeding the transition from laboratory-scale research to practical implementation—namely, performance instability arising from feedstock variability, attenuation of adsorption capacity during prolonged operation (with a 10–40% decline over 5–10 cycles), underdeveloped regeneration and recovery routes, and a systemic deficiency in techno-economic analysis and life-cycle assessment data. Finally, future research directions are proposed, emphasizing the development of low-carbon and energy-efficient preparation technologies, the promotion of synergistic valorization of multiple solid wastes alongside critical metal recovery, and the advancement of this field toward engineering applications through artificial intelligence-assisted design and life-cycle assessment, thereby furnishing theoretical references and technical support for the integrated management of industrial solid waste resource utilization and heavy metal wastewater treatment. Full article

Early, rapid, and accurate detection is essential for clinical management and epidemiological control of acute respiratory infections caused by pathogens. Traditional testing methods such as microbial culture, serological testing, and PCR are restrictive in terms of operation and logistics and are therefore not easily used in point-of-care settings. The CRISPR/Cas system is an adaptive prokaryotic immune system composed of clustered regularly interspaced short palindromic repeats and their associated proteins, which has been used as a nucleic acid diagnostic platform with programmable sequence-specific target recognition and signal-amplifying collateral cleavage activity. Existing reviews have mostly focused on the classification of Cas enzymes or amplification strategies; in this review, a pathogen-centric approach was taken, covering viral pathogens (SARS-CoV-2, influenza virus, RSV, HAdV and VZV), bacterial pathogens (Mycobacterium tuberculosis, Streptococcus pneumoniae, Mycoplasma pneumoniae and Staphylococcus aureus) and fungal pathogens (Aspergillus fumigatus and Pneumocystis jirovecii). Key technological advances, such as isothermal amplification coupling, single-vessel integrated reaction designs, amplification-free digital detection, and electrochemical biosensor integration, are evaluated for Cas9-, Cas12-, and Cas13-based systems, with their mechanistic bases outlined. The current challenges that hinder clinical translation, such as sample matrix interference, multiple signal cross-talk, crRNA off-target effects, and the lack of large-scale validation studies, are critically assessed. At the same time, future pathways for portable, integrated, and inexpensive diagnostic platforms are suggested. Full article