Search Results (1,435)

Cu-Sn-Ti metallic-bonded CBN (Cubic Boron Nitride) abrasives are widely applied in the precision grinding of superhard materials. However, their high density and high toughness easily lead to poor grain protrusion and inadequate self-sharpening. In this work, ceramic glass powder was incorporated to modify the Cu-Sn-Ti binder, thereby fabricating composite-bonded CBN abrasive blocks with qualified mechanical properties and excellent self-sharpening performance. Flexural strength of abrasive blocks and microhardness of composite binders were measured; microstructure was characterized, phase composition was analyzed by XRD, and tribological tests were carried out between CBN blocks and silicon nitride abrasives. The results indicate that at glass powder contents of 2.94–10.22 wt%, the flexural strength of CBN blocks decreases by 32.5–89.4%, and binder microhardness reduces by 26.5–58.3%. At high brazing temperature, Ti and Cu from Cu-Sn-Ti alloy react with Si and Al in glass powder at the interface to form new phases including Ti₂O₃, Ti₅Si₃ and Ti(Cu,Al)₂, which facilitates favorable interfacial bonding among the alloy matrix, glass phase and CBN grains. With increasing glass powder content, the strength decline gradually slows down. The overall wear resistance of abrasive blocks declines. SEM observations on worn CBN blocks and their composite binders reveal the formation of micropores within glass-containing binders, accompanied by a shift in the fracture mode of CBN abrasives upon glass powder addition. Comprehensive experimental analysis indicates that the No.3 sample with 8.33 wt% glass powder possesses the optimal overall performance. Full article

Lithium-ion batteries are widely used in digital, power and energy storage fields due to their high capacity and high cycle life advantages. This paper systematically screens the formulation system and designs a high-efficiency production line that can effectively improve production efficiency, reduce production costs, and lower energy consumption per unit product. The produced nano-silicon-enhanced graphite anode material has excellent performance. The selection of silicon raw materials, types of solvents, types of dispersants, and grinding processes is studied to investigate the influence of these four factors on the wet grinding process for preparing nano-silicon. Finally, metal silicon obtained by air flow pulverization is selected as the raw material, isopropanol is used as the solvent, FA01 (carboxylic acid type) is used as the dispersant, and a two-stage wet grinding process is adopted to prepare the nano-silicon dispersion solution. Zirconia beads of 0.5 mm and 0.2 mm size are used as the grinding media for the first and second stages, respectively, with filling rates of 80% and 90%, respectively. The final prepared nano-silicon dispersion is stable in dispersion and has a narrow particle size distribution. The nano-silicon dispersion solution and the multi-walled carbon nanotube dispersion solution are mechanically ground and mixed using a sand mill. At the same time, the multi-walled carbon nanotubes are coated with the nano-silicon. Then, artificial graphite is added for compounding. Finally, through spray drying, the Si@MWCNTs@graphite (SMG) nano-silicon-enhanced graphite negative electrode material is prepared. The SMG nano-silicon-enhanced graphite negative electrode material with a silicon content of 2% has a first Coulomb efficiency of up to 84.32%. Full article

Silicone gel for high-voltage power module packaging is prone to interfacial failure due to poor intrinsic adhesion, which seriously threatens the reliability of devices. This study explores ways to improve the adhesion performance of silicone gel from the two aspects of crosslink network structure and interfacial connection. The crosslink structure is regulated by adjusting the ratio of side-hydrogen-containing silicone oil to terminal-hydrogen-containing silicone oil, and interface adhesion is improved by adding three different contents of silane coupling agents (KH560, KH570, A171). The adhesion strength is evaluated by lap shear experiments. The results show that when the ratio of side-hydrogen to terminal-hydrogen is 16:24, the adhesion strength reaches a peak value of 0.0921 MPa. Among the coupling agents, KH560 shows the most significant enhancement, with the adhesion strength reaching 0.1356 MPa at 4% addition and a 47% improvement over the baseline, KH570 is only effective at low addition levels, and A171 shows the weakest effect due to vinyl interference in the crosslink network. Breakdown tests confirm that all three modification schemes do not seriously damage insulation performance. This study provides a feasible strategy and basis for the adhesion reliability design of silicone gel for power module packaging. Full article

Integrated circuits (ICs), a major fraction of waste electrical and electronic equipment (WEEE), represent an important secondary source of gold (Au). However, recovering high-purity Au from ICs remains challenging due to the high silicon dioxide content that encapsulates Au within the IC core and the presence of complex base-metal mixtures that hinder selective purification. This study proposes a simplified end-to-end process that integrates mechanical liberation, magnetic separation, oxidative chlorination, ion-exchange purification and Au recovery from isolated ICs. Unlike conventional multi-stage comminution routes, the proposed pretreatment combines hydraulic pressing, milling/sieving and magnetic separation to maximize Au exposure while minimizing dust generation, metal losses and base-metal interference, which is subsequently subjected to oxidative leaching and purification. Optimal extraction conditions, determined through a Taguchi design (2.5 M HCl, 0.34 M NaClO, 40 °C, solid–liquid ratio 1 g/40 mL, 3 h), achieved a Au leaching efficiency of 89%. The resulting multi-metal leachate was treated with a strong anionic ion-exchange resin, increasing Au purity from 8% to 86% after thiourea elution in a sulfuric-acid medium. Final Au recovery was completed by reductive precipitation with sodium borohydride, yielding complete solidification (~100% efficiency). A comparative life-cycle assessment showed that this recycling route offers favourable environmental performance relative to primary mining. Beyond achieving efficient Au recovery, this work establishes an integrated recovery route for isolated ICs that combines process simplification with environmental positive impact, addressing an important gap in WEEE recycling. Full article

This study systematically investigates the effects of varying Ni doping levels (1.0–7.0 wt.%) on the microstructure, static magnetic properties, and high-frequency dynamic magnetic performance of Fe-5.5 wt.% Si soft magnetic composites (SMCs). Toroidal core samples were fabricated using powder metallurgy combined with silicone resin coating and high-temperature annealing. The influence of Ni doping on phase composition, morphology, saturation magnetization, coercivity, effective permeability, quality factor, total core loss and its components, and DC bias characteristics was comprehensively evaluated by XRD, SEM, EDS, hysteresis loop testing, and DC bias measurements. The results indicate that an appropriate Ni content (3.0–5.0 wt.%) promotes the formation of α-Fe(Si,Ni) solid solution and (Fe,Ni)₃Si ordered phases, optimizes grain size and structural ordering, enhances saturation magnetization, and reduces coercivity. In contrast, excessive Ni doping (7.0 wt.%) leads to Ni segregation at grain boundaries, forming strong pinning centers that significantly increase coercivity and hysteresis loss. Within the wide frequency range of 1–100 kHz, Ni doping improves the permeability retention under DC bias but reduces the initial effective permeability. Notably, the sample with 5.0 wt.% Ni exhibits the highest quality factor (Q value) across the entire frequency range, demonstrating the best overall performance. This study provides experimental evidence and theoretical guidance for developing high-saturation-resistance, low-loss soft magnetic composites for medium-to-high-frequency applications. Full article

Background: Ultrafine particles (UFPs) represent a significant occupational health concern in commercial cooking environments, yet comprehensive exposure assessment in pizzerias remains limited despite their global prevalence and unique cooking processes. Understanding UFP exposure patterns and associated health effects in this widespread food service sector is crucial for protecting worker health. Objective: To quantify occupational exposure to airborne UFPs among pizzeria workers across different oven technologies. Methods: A cross-sectional observational study was conducted in 10 pizzerias in the Cagliari metropolitan area (April 2022–March 2024), encompassing wood-fired ovens (WFO, n = 6), electric ovens (EO, n = 3), and mixed systems (BO, n = 1). Ventilation characteristics were documented at each site to evaluate their influence under real-world operating conditions. Personal UFP exposure was measured using DISCmini diffusion size classifiers (10–700 nm range), while qualitative particle characterization employed ELPI+ impaction with SEM-EDS analysis. Results: UFP concentrations varied dramatically by oven type, with median values of 3.18 × 10⁴ particles/cm³ (WFO), 1.29 × 10⁵ particles/cm³ (EO), and 2.55 × 10⁵ particles/cm³ (BO). Seven of ten pizzerias exceeded WHO precautionary limits (20,000 particles/cm³), with electric oven facilities showing concentrations comparable to high-emission industrial operations. Elemental analysis revealed predominantly carbon-based particles with significant iron, aluminum, and silicon content, indicating combined combustion and mechanical abrasion sources. Conclusions: Pizzeria workers experience substantial UFP exposure levels that frequently surpass those in other food service environments and approach levels typically observed in high-exposure industrial workplaces. Electric ovens generate significantly higher UFP levels than wood-fired systems, likely due to ventilation efficiency differences. Full article

The sustainable management of almond (Prunus dulcis) hulls and shells represents a major challenge for the global almond industry. Although almond hulls possess considerable nutritional value and can be used as livestock feed, concerns about pesticide residues limit their utilisation and pose environmental and economic disposal challenges. Therefore, alternative crop protection strategies that reduce reliance on chemical pesticides while maintaining productivity are required. Silicon has been widely reported to enhance plant resistance against biotic and abiotic stresses, improve nutrient utilisation, and increase crop productivity. This study evaluated the effects of an enhanced potassium silicate formulation applied through fertigation on pest and disease incidence, plant performance, and kernel yield in a commercial almond orchard over two consecutive growing seasons. The formulation contained potassium silicate (50% w/v), amino acids (42% w/v), Complex Polymeric Poly-Hydroxy Acid (CPPA) (1.5% w/v), and water. Treatments were applied twice per season at a rate of 30 L ha⁻¹ and compared with a grower-standard management program. Silicon-treated trees exhibited significantly lower levels of microbial disease damage in both leaves and mature nuts compared with untreated controls. Across the two growing seasons, pest- and disease-related damage to nuts was reduced by up to 59%. Silicon treatment also resulted in substantial increases in oven-dried kernel weight, ranging from 19% to 33% across the evaluated almond varieties. No adverse effects were observed on flower-to-nut conversion, chlorophyll content, kernel nutritional quality, or leaf nutrient status. The findings demonstrate that enhanced potassium silicate fertigation can improve pest and disease resistance while increasing kernel yield in commercial almond production systems. The technology offers a promising strategy for reducing reliance on chemical pesticides and supporting the sustainable utilisation of almond by-products, including their use in livestock feed and bioenergy production. Full article

Intumescent coatings are widely used to enhance the fire resistance of structural steel. In contrast to traditional fire protection methods, this novel flexible intumescent protection offers several key advantages: universal compatibility with other coatings (via non-contact wrapping), resistance to extreme temperatures (−60 °C to +90 °C), all-weather usability, and suitability for light-gauge cold-formed thin-walled steel structures. This paper describes the development and investigation of these fire-protective, flexible intumescent coatings based on eco-friendly binders (silicone polymers and acrylic resins) with varying intercalated graphite (IG) content from 0% to 40%. An IG content of 25–40% enables a steel I-section with a section factor of 294 mm⁻¹ to reach its limit state at 44 min (compared to 15 min for unprotected steel). Fire tests on steel beams with a section factor of 172 mm⁻¹ demonstrated that samples reached the deflection limit state at the 64th and 66th minutes, respectively. Thermogravimetric analysis (TGA) was used to determine the temperature ranges for the thermal decomposition and expansion of the IG. Mechanical property studies revealed the influence of IG on the elastic modulus and tensile strength. Accelerated climatic testing in moderately cold conditions and salt spray chamber tests confirmed that the intumescent roll coating has no negative impact on the steel substrates. Full article

Water deficit is a major abiotic constraint limiting maize growth and productivity worldwide. Although silicon (Si) is not classified as an essential element, its beneficial effects on numerous crop species are well documented. Silicon has been shown to promote plant growth and enhance tolerance to abiotic stresses, particularly drought stress. Seed priming, a pre-sowing technique known to stimulate early germination processes, has emerged as a promising approach to enhance seedling establishment and stress tolerance in crops. In the present study, silicon-based seed priming was investigated as a strategy to alleviate the adverse effects of water deficit in maize (Zea mays) using two sodium silicate priming-solution concentrations (10 and 20 mM). Maize plants were subjected to six experimental treatments based on seed priming: three under well-watered conditions (no silicon seed priming and seed priming with 10 and 20 mM sodium silicate solutions) and three corresponding treatments combined with irrigation withdrawal for 15 days to induce drought stress. Morphological traits, biomass accumulation, photosynthetic pigment content, plant water status, and PSI- and PSII-related photochemical parameters were evaluated. Drought stress markedly reduced plant growth, biomass production, relative water content, chlorophyll pigment levels, and photosystem photochemical performance, reflecting a strong negative impact of water deficit on most measured parameters. In particular, root and shoot fresh weights decreased by 75% and 71%, respectively, compared with those of well-watered unprimed control plants, indicating a substantial reduction in biomass accumulation under drought conditions. Furthermore, drought conditions impaired photochemical performance and increased non-regulated energy dissipation, indicative of impaired photosynthetic performance. Silicon seed priming mitigated several drought-induced effects in a trait-dependent manner. Under water-deficit conditions, 20 mM Si produced the strongest improvement in root and shoot fresh weights, whereas 10 mM Si showed stronger responses for selected shoot-growth and PSI-related parameters. Both Si treatments improved leaf water status and photosynthetic stability to varying extents. Collectively, these results indicate that sodium silicate seed priming partially improves drought-related responses in maize seedlings under the conditions of this study by sustaining growth performance, preserving plant water status, and maintaining photosynthetic stability under water-deficit conditions. Full article

Soil salinization critically restricts melon production, and the seed germination stage is particularly vulnerable to saline–alkali stress (SAS). Although silicon (Si) is known to enhance plant stress tolerance, its role in alleviating SAS-induced inhibition of melon seed germination—particularly under combined neutral and alkaline salt stress—remains insufficiently characterized. Here, using the melon cultivar ‘Xinyinhui’, we simulated SAS with a mixture of NaCl and NaHCO₃ and screened for the optimal Si concentration. We then systematically examined physiological, biochemical, and gene expression responses. SAS significantly inhibited germination (20.4% reduction in germination rate; 56.9% in vigor index) and induced oxidative damage (MDA increased by 9.7%; superoxide anion by 170.6%), suppressed antioxidant enzyme activities (SOD −28.8%, POD −69.4%), and disturbed starch metabolism. Exogenous Si at 1.25 mmol·L⁻¹ effectively alleviated these effects: The germination rate increased from 71.7% to 88.8%, and SOD and POD activities increased by 26.7% and 63.6%, while MDA and superoxide anion decreased by 7.1% and 16.4%. Si also promoted starch degradation, as indicated by a 13.9% reduction in starch content, 8.4% increase in total amylase activity, and 23.2% upregulation of CmBMY expression. In addition, Si significantly improved root morphology: Root surface area, volume, branch number, and tip number increased by 19.8–326.3%, while the average root diameter decreased by 24.4%. These results suggest that exogenous Si alleviates SAS inhibition of melon seed germination through coordinated regulation of antioxidant defense and starch metabolism rather than through a single pathway. Our findings provide a physiological basis for the potential application of Si fertilizer in melon cultivation under saline–alkali conditions. Full article

The Böhme abrasion test (EN 14157) is widely used to evaluate the wear resistance of natural stones; however, the abrasive powder specified by TS 699 requiring 70–80 wt.% crystalline Al₂O₃ is not commercially available in the Turkish market. Commercially supplied abrasives deviate substantially from both the prescribed chemical composition and the grain-size distribution of TS 699, introducing a recognized but unresolved source of variability in Böhme abrasion measurements. This study evaluates the influence of abrasive type and particle-size distribution on Böhme abrasion performance with the aim of identifying which available abrasive material yields the most reliable and reproducible test results. The emphasis is therefore metrological—on test repeatability and standardization—rather than on ranking the abrasion resistance of the stones. Six natural stones representing contrasting lithologies—four crystalline marbles, one limestone, and one granite—were tested using five abrasive powders: two locally produced natural emery abrasives (Emery-1 and Emery-2), silicon carbide (SiC), white corundum, and brown corundum. Each abrasive was evaluated under both standardized graded conditions prepared in accordance with TS 699 and heterogeneous ungraded conditions reflecting common industrial practice. Chemical analyses confirmed that both emery abrasives deviate markedly from TS 699 specifications, with Al₂O₃ contents (~57.7 wt.%) well below the required range and Fe₂O₃ (~24 wt.%) considerably exceeding the standard limit. Sieve analyses further revealed substantial particle-size deviations in several commercial abrasives. One-way ANOVA demonstrated that abrasive type exerts a statistically significant influence on abrasion performance (F = 8.99, p < 0.05, η² = 0.297). SiC consistently produced the highest abrasion values, followed by corundum-based abrasives, while emery abrasives showed comparatively lower but stable performance. Independent-samples t-tests showed that particle-size grading significantly affected abrasion performance only for brown corundum (p < 0.05), attributable to its markedly elevated coarse particle fraction. Petrographic analysis, XRD, and SEM–EDS characterization of the investigated rocks confirmed that abrasion response is additionally modulated by rock mineralogy and microstructure. Under standardized grading conditions, SiC provided the most consistent and reproducible results across all lithologies, supporting its suitability as the reference abrasive for inter-laboratory Böhme testing. Locally produced emery abrasives, despite their chemical non-compliance with TS 699, yielded stable and reproducible outcomes under controlled grading, supporting their potential as cost-effective alternatives for routine testing. Full article

To address the potential ecological risks and environmental persistence of organosilicon-fluorine viscosity reducers in conventional silicone-fluoride drilling fluid systems, this work designs and synthesizes a non-organosilicon-fluorine, high-temperature, comb-shaped zwitterionic polymer viscosity reducer, AD-XSJ. The viscosity reducer is prepared via aqueous free-radical polymerization of acrylic acid (AA), acrylamide (AM), 2-acrylamido-2-methylpropane sulfonic acid (AMPS), and dimethyl diallyl ammonium chloride (DADMAC), and it exhibits low molecular weight, uniform molecular weight distribution, and excellent thermal stability. Analyses by FT-IR, thermogravimetry, particle size, zeta potential measurements and Electrostatic potential (ESP) demonstrate that AD-XSJ dismantles the bentonite network structure through the synergistic combination of hydrogen-bonding adsorption and electrostatic repulsion, releasing trapped free water and thereby substantially reducing viscosity and gel strength. Compared with conventional organosilicon-fluorine viscosity reducers, AD-XSJ exhibits superior viscosity reduction capability under high-solid, high-temperature, and high-salinity calcium-contamination conditions, achieving viscosity reduction rates of 33.3% and 50.0% in fluids contaminated with 10.0% NaCl and 1.0% CaCl₂, respectively. In field applications under conditions of high bentonite content and calcium contamination, the viscosity reduction rates reach 57.7% and 62.5%, accompanied by markedly improved rheological properties and an average borehole enlargement rate of only 5.7%, indicating effective shale inhibition and anti-sloughing performance. Integrating efficient viscosity reduction, dispersion stabilization, and inhibition capabilities, this viscosity reducer can replace traditional organosilicon-fluorine products, reduce potential hazards to aquatic ecosystems at the source, and holds considerable promise for engineering and environmentally conscious deployment. Full article

The growing demand for efficient and sustainable materials for air purification has stimulated interest in activated carbons derived from renewable biomass resources. In this study, activated carbons were prepared from Rice Husk, Wheat Straw, Sawdust, and Walnut shells and systematically investigated as sorbents for toxic gases and volatile organic compounds. The materials were characterized using nitrogen and water vapor sorption isotherms, scanning electron microscopy, thermogravimetric analysis, Fourier-transform infrared spectroscopy, energy-dispersive X-ray and XPS analysis to evaluate their textural properties, morphology, thermal stability, and surface chemistry. The results showed that the precursor type strongly influences the pore structure and functional group composition of the activated carbons. Wheat straw and Rice Husk-derived activated carbons exhibited the highest total pore volume and a well-developed porous structure, together with a high content of oxygen- and silicon-containing elements. Gas breakthrough experiments with different probes showed that Wheat Straw-derived activated carbon excels in non-polar VOC—cyclohexane removal due to its highly microporous structure. In contrast, Rice Husk-derived activated carbon displays strong affinity toward inorganic gases such as NH₃ and, after urea modification, achieves enhanced performance for SO₂. These results underscore the versatility and practical applicability of carbon materials obtained from plant residues. Full article

The integration of advanced semiconductor architectures strictly mandates process thermal budgets below 200 °C, positioning low-temperature PECVD of silicon nitride (SiN_x) film as a critical layer. However, SiN_x film deposited at sub-200 °C inherently exhibits sluggish deposition kinetics and degraded spatial uniformity. To overcome these bottlenecks, this study systematically investigates the regulatory mechanisms of the NH₃ precursor within SiH₄/N₂-based plasmas under varying chamber pressures and substrate temperatures. The results show that the introduction of NH₃ at 2.1 Torr, leveraging its facile plasma dissociation, drastically enhances the deposition rate from 18.2 to 39.1 Å/s and improves thickness uniformity by 1.07%. Meanwhile, NH₃ supplies abundant highly reactive radicals that elevate the refractive index and reinforce compressive stress. Furthermore, film properties exhibit a higher sensitivity to pressure than to temperature, primarily due to the pronounced influence of pressure on plasma dynamics and collision frequencies, whereas the effect of temperature remains comparatively minor. This phenomenon is clearly demonstrated by the Si–H and N–H content. This study validates that operating at low chamber pressures maximizes the collision-free travel distance of SiN_x radicals, providing an optimized and quantified process window for high-volume manufacturing of low-temperature SiN_x film. Full article

Silicon nitride ceramics exhibit excellent structural strength and electromagnetic wave transmission performance, yet demonstrate significant thermal shock instability under extreme conditions. Boron nitride (BN), on the other hand, possesses outstanding thermal shock resistance and electromagnetic wave transmission properties but exhibits relatively lower structural strength. Compositing these two materials holds promise for developing an integrated material that combines high-temperature load-bearing capacity with wave transmission capability. This study employed spark plasma sintering (SPS) technology to systematically investigate how varying BN content affects the sintering densification process and microstructural evolution of Si₃N₄/BN composite ceramics. Furthermore, we elucidated the mechanisms by which material composition and processing parameters influence key mechanical properties, dielectric characteristics, and other multifunctional attributes of the composites, providing a theoretical foundation for synergistic optimization design. The results indicate that BN incorporation suppresses both the phase transition from α-Si₃N₄ to β-Si₃N₄ during sintering and the growth of elongated β-Si₃N₄ crystals: the former hinders densification while the latter promotes it, resulting in a dual competitive mechanism that initially increases followed by decreases in sintered density. The effects of BN content on elastic modulus and fracture toughness align with trends in sintering density, whereas hardness, flexural strength, dielectric constant, and dielectric loss all show a monotonically decreasing trend with increasing BN content. Full article