Search Results (265)

Viticulture is increasingly seeking sustainable practices that enhance grape quality while reducing reliance on synthetic inputs. Among bio-based strategies, biochar has attracted growing interest for its potential to improve soil fertility and influence plant metabolism. However, its effects can vary depending on formulation and application methods. This study evaluated the effects of the use of solid (SB) and liquid biochar (LB) on the biochemical and nutritional composition in leaves, berry skins, and must of a grapevine (Vitis vinifera L., cv. Sangiovese) cultivated in a vineyard in Tuscany (Italy). SB was applied once to the soil at 2.5% (w/w), while LB was applied five times/season at 10% (v/v) via fertigation. Results revealed formulation-specific effects on grapevine physiology and fruit composition. SB maintained leaf chlorophyll concentrations, increased total soluble proteins (+65%), total polyphenols (+57%), and tannin content (+33%) in berry skins and must, and reduced Cu and Zn. Conversely, LB reduced leaf chlorophyll concentrations (−24%) and nutrient contents (P, Fe, Cu, and Zn), but increased total flavonoids (+13%), antioxidant capacity (+20%), and vitamin C (+18%) in berry skins, alongside higher fructose and reducing sugars in musts. The findings highlight biochar’s potential as a bio-based input in viticulture, emphasizing the importance of formulation and application strategy. SB appears suited to long-term soil improvement and enhanced phenolic richness, while LB may modulate sugar metabolism for targeted enological outcomes. Full article

In order to enhance the heat dissipation of a chip, this work investigates the enhancement of the thermal homogenization effect of a ceramic substrate with a high-thermal-conductivity graphene material to improve the interfacial heat transfer performance. AgCuTi-activated brazing material is used to connect the graphene film/AlN. The mechanism of the influence of brazing temperatures on the microstructure and thermal conductivity of joints is discussed. The thermal conductivity of the graphene/AlN double layer composite brazed at 890 °C for 10 min holding time was the highest at 482.3 W m⁻¹ K⁻¹. This study provides a new solution for the application of AlN ceramics in high-heat-flow scenarios. Full article

W-type hexaferrites with compositions Ba_0.5Sr_0.5Zn_2-xMe_xFe₁₆O₂₇ (Me = Fe, Ni, Co, Cu, Mn; x = 1) and Ba_0.5Sr_0.5Zn_2−xMn_xFe₁₆O₂₇ (x = 0–2.0) were synthesized via solid-state reaction and optimized using a two-step calcination process to obtain single-phase or nearly single-phase structures. Their electromagnetic (EM) wave absorption properties were investigated by fabricating composites with 10 wt% epoxy and measuring the complex permittivity and permeability across two frequency bands: 0.1–18 GHz and 26.5–40 GHz. Reflection loss (RL) was calculated and visualized as two-dimensional (2D) maps with respect to frequency and sample thickness. In the 0.1–18 GHz range, only the Co-substituted sample exhibited strong ferromagnetic resonance (FMR) and broadband absorption, achieving a minimum RL of −41.5 dB at 4.84 GHz and a −10 dB bandwidth of 11.8 GHz. In contrast, the other Ba_0.5Sr_0.5Zn_2-xMe_xFe₁₆O₂₇ samples (Me = Fe, Mn, Ni, Cu) showed no significant absorption in this range due to the absence of FMR. However, all these samples clearly exhibited FMR characteristics and distinct absorption peaks in the 26.5–40 GHz range, particularly the Mn-substituted series, which demonstrated RL values below −10 dB over the 32.0–40 GHz range with absorber thicknesses below 1 mm. The FMR frequency varied depending on the substitution type and amount. In the Mn-substituted series, the FMR frequency was lowest at x = 1.0 and increased as x deviated from this composition. This study confirms the potential of Co-free W-type hexaferrites as efficient, cost-effective, and broadband EM wave absorbers in the 26.5–40 GHz range. Full article

Skutterudite (CoSb₃)-based thermoelectric materials are regarded as one of the most promising candidates for mid-temperature commercial thermoelectric applications, thanks to their excellent electrical performance and alloy-based attributes. By utilizing techniques such as doping, microstructure design, and high-temperature solid-state reactions, synthesis of Brass_x/Co₄Sb_11.5Te_0.5 (x = 0.1, 0.3, 0.5, 0.7, representing wt%) in composite form can be rapidly achieved. XRD analysis indicates that the prepared Brass_x/Co₄Sb_11.5Te_0.5 samples primarily exhibit the CoSb₃ crystal structure, with the formation of minor impurity phases such as Cu₁₃Te₇ and ZnTe. SEM and EDS analyses reveal that the sample is composed of nanoscale equiaxed grains, some of which are micrometer in size, with a large number of microporous structures distributed uniformly, forming abundant grain boundaries. By co-doping with brass and tellurium (Te), the carrier concentration can be effectively regulated, thereby enhancing the power factor of CoSb₃-based thermoelectric materials. Meanwhile, the introduction of nanostructures, grain boundaries, and defects optimizes the microstructure of the samples, leading to a reduction in the lattice thermal conductivity of the CoSb₃-based thermoelectric materials. At a testing temperature of 781 K, Brass_0.1/Co₄Sb_11.5Te_0.5 achieved a maximum power factor of 1.86 mW·m⁻¹·K⁻², a minimum lattice thermal conductivity of 1.02 W/(mK), and a maximum thermoelectric figure of merit ZT of 0.81. Full article

Diamond–copper composites, due to their exceptional thermal conductivity, hold significant potential in the field of electronic device thermal management. Hot-press sintering is a promising fabrication technique with industrial application prospects; however, the thermal conductivity of composites prepared by this method has yet to reach optimal levels. In this study, tungsten was deposited on the surface of diamond particles by magnetron sputtering as an interfacial transition layer, and hot-press sintering was employed to fabricate the composites. The findings reveal that with prolonged annealing time, tungsten gradually transformed into W₂C and WC, significantly enhancing interfacial bonding strength. When the diamond volume content was 50% and the interfacial coating consisted of 2 wt.% W, 92 wt.% WC, and 6 wt.% W₂C, the composite exhibited a thermal conductivity of 640 W/(m·K), the highest value reported among hot-press sintered composites with diamond content below 50%. Additionally, the AMM (Acoustic Mismatch Model) and DMM (Diffusion Mismatch Model) models were utilized to calculate the interfacial thermal conductance between different phases, identifying the optimal interfacial structure as diamond/W₂C/WC/W₂C/Cu. This composite material shows potential for application in high-power electronic device cooling, thermal management systems, and thermoelectric conversion, providing a more efficient thermal dissipation solution for related devices. Full article

Supercapacitors have begun to successfully compete with Li-ion batteries in various portable energy storage applications, owing to their ability to enable fast charging, deliver high power and energy, and offer an exceptionally long cycle life. This paper presents the results of a study on the performance of a positive electrode composed of a Cu_xZn_1−xCoNiS_yO_4−y whisker layer and an underlying porous Ni₃S₂ layer, synthesized in a single step via the hydrothermal method. The coating with the nominal composition Cu_0.7Zn_0.3CoNiS₃O/Ni₃S₂ exhibited a high specific capacitance of 4.10 C cm⁻² at a current density of 2 mA cm⁻² or 9535 F g⁻¹ at a current density of 1 A g⁻¹, attributed to the synergistic contribution of both layers and the optimized ratio of the four transition metals in the sulfoxide matrix. The assembled asymmetric supercapacitor (ASC), employing the obtained composite as the positive electrode and activated carbon as the negative electrode, exhibited a specific capacitance of 115 F g⁻¹ (200 C g⁻¹). It achieved a high energy density of 48.3 Wh kg⁻¹ at a power density of 870 W kg⁻¹. After 20,000 charge–discharge cycles at a current density of 10 A g⁻¹, the ASC retained 74% of its initial capacitance, highlighting the potential of the Cu_xZn_1−xCoNiS_yO_4−y electrode for high-performance energy storage applications. Full article

Lithium/carbon fluoride (Li/CF_x) batteries are promising for specialized applications due to their high theoretical capacity (>865 mAh·g⁻¹) and energy density. However, their practical deployment is hindered by the intrinsically low conductivity of CF_x and sluggish reaction kinetics. While conventional conductive additives improve electron transport, their physical mixing with active materials yields weak interfacial contacts and fails to catalytically facilitate C–F bond cleavage. To address these dual limitations, this study proposes a dual-functional conductive-catalytic additive strategy. We engineered zinc-nickel/carbon nanotube (ZnNi/CNT) composites modified with transition metal dopants (Fe, W, Cu) to integrate conductive networks with nanoscale-dispersed catalytic sites. Fe-doped ZnNi/CNT (ZnFeNiC) emerged as the optimal system, delivering a discharge plateau of 2.45 V and a specific capacity of 810.3 mAh·g⁻¹ at 0.1 C. This performance is attributed to Fe-doping accelerates Li⁺ diffusion, and promotes reversible Ni redox transitions (Ni²⁺↔Ni⁰) that catalyze C–F bond dissociation. This work establishes a design paradigm for high-performance Li/CF_x batteries, bridging the gap between conductive enhancement and catalytic activation. Full article

This study explores the magmatic and hydrothermal evolution of porphyry–skarn–transitional Cu-Mo-W-Au systems within the Nilüfer Mineralization Complex (NMC), located in the westernmost segment of the Eocene Tavşanlı Metallogenic Belt, NW Türkiye. Through integration of field data, whole-rock geochemistry, Re–Os molybdenite dating, and amphibole–biotite mineral chemistry, the petrogenetic controls on mineralization across four spatially associated mineralized regions (Kirazgedik, Güneybudaklar, Kozbudaklar, and Delice) were examined. The earliest and thermally most distinct phase is represented by the Kirazgedik porphyry system, characterized by high temperature (~930 °C), oxidized quartz monzodioritic intrusions emplaced at ~2.7 kbar. Rising fO₂ and volatile enrichment during magma ascent facilitated structurally focused Cu-Mo mineralization. At Güneybudaklar, Re–Os geochronology yields an age of ~49.9 Ma, linking Mo- and W-rich mineralization to a transitional porphyry–skarn environment developed under moderately oxidized (ΔFMQ + 1.8 to +0.5) and hydrous (up to 7 wt.% H₂O) magmatic conditions. Kozbudaklar represents a more reduced, volatile-poor skarn system, leading to Mo-enriched scheelite mineralization typical of late-stage W-skarns. The Delice system, developed at the contact of felsic cupolas and carbonates, records the broadest range of redox and fluid compositions. Mixed oxidized–reduced fluid signatures and intense fluid–rock interaction reflect complex, multistage fluid evolution involving both magmatic and external inputs. Geochemical and mineralogical trends—from increasing silica and Rb to decreasing Sr and V—trace a systematic evolution from mantle-derived to felsic, volatile-rich magmas. Structurally, mineralization is controlled by oblique fault zones that localize magma emplacement and hydrothermal flow. These findings support a unified genetic model in which porphyry and skarn mineralization styles evolved continuously from multiphase magmatic systems during syn-to-post-subduction processes, offering implications for exploration models in the Western Tethyan domain. Full article

Over efficient photocatalysts, CO₂ photoreduction typically converts CO₂ into low-carbon chemicals, which serve as raw materials for downstream synthesis processes. Here, an efficient composite photocatalyst heterojunction (Cu₂O-u/g-C₃N₄) has been fabricated to reduce CO₂. Graphitic carbon nitride (g-C₃N₄) was synthesized via thermal polymerization of urea at 550 °C, while pre-dispersed Cu₂O derived from urea pyrolysis (Cu₂O-u) was prepared by thermal reduction of urea and CuCl₂·2H₂O at 180 °C. The heterojunction Cu₂O-u/g-C₃N₄ was subsequently constructed through hydrothermal treatment at 180 °C. This heterojunction exhibited a bandgap of 2.10 eV, with dual optical absorption edges at 485 nm and above 800 nm, enabling efficient harvesting of solar light. Under 175 W mercury lamp irradiation, the heterojunction catalyzed liquid-phase CO₂ photoreduction to formic acid, acetic acid, and methanol. Its formic acid production activity surpassed that of pristine g-C₃N₄ by 3.14-fold and TiO₂ by 8.72-fold. Reaction media, hole scavengers, and reaction duration modulated product selectivity. In acetonitrile/isopropanol systems, formic acid and acetic acid production reached 579.4 and 582.8 μmol·h⁻¹·g_cat⁻¹. Conversely, in water/triethanolamine systems, methanol production reached 3061.6 μmol·h⁻¹·g_cat⁻¹, with 94.79% of the initial conversion retained after three cycles. Finally, this work ends with the conclusions of the CO₂ photocatalytic reduction to formic acid, acetic acid, and methanol, and recommends prospects for future research. Full article

Plow loosening machines are essential agricultural machinery in the agricultural production process. Improving the surface strengthening process and extending the working life of the plow teeth of the plow loosening machine are of great significance. In this paper, the preparation of Stellite6/Cu composite coating on the surface of 316L steel substrate intended for strengthening the plow teeth of a plow loosening machine using laser cladding technology was studied. The influence of different laser process parameters on the microstructure and properties of Stellite6/Cu composite coating was investigated. The composite coating powder was composed of Stellite6 powder with a different weight percent of copper. Microstructural analysis, phase composition, elemental distribution, microhardness, wear resistance, and corrosion resistance of the composite coatings on the plow teeth were analyzed using scanning electron microscopy (SEM), X-ray diffraction (XRD), microhardness testing, energy dispersive spectroscopy (EDS), friction and wear testing, and electrochemical workstation measurements. The results showed that (1) When the laser power was 1000 W, the average hardness of the prepared Stellite6/Cu composite layer achieved the highest hardness, approximately 1.36 times higher than the average hardness of the substrate, and the composite coating prepared exhibited the best wear resistance; (2) When the scanning speed was 800 mm/min, the composite coating exhibited the lowest average friction coefficient and the optimal corrosion resistance in a 3.5% wt.% NaCl solution with a self-corrosion current density of −7.55 µA/cm²; (3) When the copper content was 1 wt.%, the composite coating achieved the highest average hardness with 515.2 HV, the lowest average friction coefficient with 0.424, and the best corrosion resistance with a current density of −8.878 µA/cm². Full article

Free-standing copper oxide (Cu₂O)-copper hydroxide (Cu(OH)₂) nanocomposites with enhanced catalytic and antibacterial functionalities were synthesized on copper mesh using a green method based on spinach leaf extract and glycerol. EDX, SEM, and TEM analyses confirmed the chemical composition and morphology. The resulting Cu2O-Cu(OH)₂@Cu mesh exhibited notable hydrophobicity, achieving a contact angle of 137.5° ± 0.6, and demonstrated the ability to separate thick oils, such as HD-40 engine oil, from water with a 90% separation efficiency. Concurrently, its photocatalytic performance was evaluated by the degradation of methylene blue (MB) under a weak light intensity of 5 mW/cm², achieving 85.5% degradation within 30 min. Although its application as a functional membrane in water treatment may raise safety concerns, the mesh showed significant antibacterial activity against both Gram-positive (Staphylococcus aureus) and Gram-negative (Escherichia coli) bacteria under both dark and light conditions. Using the disk diffusion method, strong bacterial inhibition was observed after 24 h of exposure in the dark. Upon visible light irradiation, bactericidal efficiency was further enhanced—by 17% for S. aureus and 2% for E. coli. These findings highlight the potential of the Cu₂O-Cu(OH)₂@Cu microfibers as a multifunctional membrane for industrial wastewater treatment, capable of simultaneously removing oil, degrading organic dyes, and inactivating pathogenic bacteria through photo-assisted processes. Full article

Microalgae-based bioremediation is increasingly recognized as a sustainable, efficient, and straightforward technology. Despite this growing interest, the potential of Parachlorella hussii for metal biosorption remains underexplored. This study is the first report evaluating the metal biosorption activity in Parachlorella hussii ACOI 1508 (N9), highlighting the impact of the culture age on the monosaccharide composition and its correlation to the metal binding capacity. The capsular strain (N9) was isolated from the hypersaline ecosystem—Lake Chott Aïn El-Beida—in southeastern Algeria. Cultivated in Bold’s Basal medium, the strain produced 0.807 ± 0.059 g L⁻¹ of RPSs and 1.975 ± 0.120 g L⁻¹ of CPSs. Biochemical analysis of the extracts revealed a high total sugar content (% w/w) that ranged from 62.98 ± 4.87% to 95.60 ± 87% and a low protein content (% w/w) that ranged from 0.49 ± 0.08% to 1.35 ± 0.69%, with RPS-D7 and RPS-D14 having high molecular weight (≥2 MDa). HPLC-based monosaccharide characterization demonstrated compositional differences between the exponential and stationary phases, with rhamnose dominating (~55%) in RPS-D14 and with the presence of uronic acids comprising 7–11.3%. Metal removal efficiency was evaluated using the whole biomass in two growth phases. Copper uptake exhibited the highest capacity, reaching 18.55 ± 0.61 mg Cu g⁻¹ DW at D14, followed by zinc removal with 6.52 ± 0.61 mg Zn g⁻¹ DW. Interestingly, removal efficiencies increased to about twofold during the stationary phase, reaching 51.15 ± 1.14% for Cu, 51.08 ± 3.35% for Zn, and 36.55 ± 3.09% for Ni. The positive results obtained for copper/zinc removal highlight the biosorption potential of P. hussii, and notably, we found that the metal removal capacity significantly improved with culture age—a parameter that has been poorly investigated in prior studies. Furthermore, we observed a growth phase-dependent modulation in monosaccharide composition, which correlated with enhanced functional properties of the excreted biomolecules involved in biosorption. This metabolic adjustment suggests an adaptive response that may contribute to the species’ effectiveness in heavy metal uptake, underscoring its novelty and biotechnological relevance. Full article

Cigarette smoking exposes individuals to numerous toxic substances, including heavy metals. Smokers are at risk due to the accumulation of these substances in various tissues. Objective: To compare the concentrations of 41 elements in 11 brain regions, the spinal cord, the bronchial, the lungs, and the liver in smokers (n = 11) and non-smokers (n = 17). Elemental composition was determined by ICP-MS after wet digestion in a microwave system. The following toxic elements were detected at levels of µg/g w.w.: Al, Cd, Pb, Ba, As, Ni, and Tl. Significantly higher concentrations of Al were detected in bronchial and lung, and more Pb, Tl, and rare earth elements were detected in the liver of smokers compared to non-smokers. In addition, smokers had significantly lower concentrations of essential elements involved in antioxidant defense, such as Cu, in liver tissue (p = 0.033). The brain and spinal cord in smokers and non-smokers were similar in terms of chemical composition, except the insula, where smokers had greater Al accumulation (p = 0.030), the precentral gyrus, where higher amounts of As, Cd, and Mn were detected, and the septal nucleus accumbens, which preferentially accumulated Cd in smokers; however, the p-values indicate that these differences were not statistically significant. Most brain areas of smokers were characterized by higher Na content (p < 0.05). These findings prove the long-term effects of smoking, demonstrating the bioaccumulation of toxic elements, the increased levels of rare earth elements in the liver, decreased levels of elements involved in the body’s antioxidant defense, and disruption of sodium homeostasis in the brain of smokers. Full article

The demand for high-performance supercapacitors has driven extensive research into novel electrode materials with superior electrochemical properties. This study explores the supercapacitive behavior of quaternary CuNiCoZnO (CNCZO) films engineered into a three-dimensional (3D) flower-like morphology and developed on versatile substrates, including carbon cloth, stainless steel mesh, and nickel foam. The unique structural design, comprising interconnected nanosheets, enhances the electroactive surface area, facilitates ion diffusion, and improves charge storage capability. The synergistic effect of the multi-metallic composition contributes to remarkable electrochemical characteristics, including high specific capacitance, excellent rate capability, and outstanding cycling stability. Furthermore, the influence of different substrates on the electrochemical performance is systematically investigated to optimize material–substrate interactions. Electrochemical evaluations reveal outstanding specific capacitance values of 2318.5 F/g, 1993.7 F/g, and 2741.3 F/g at 2 mA/cm² for CNCZO electrodes on stainless steel mesh, carbon cloth, and nickel foam, respectively, with capacitance retention of 77.3%, 95.7%, and 86.1% over 5000 cycles. Furthermore, a symmetric device of CNCZO@Ni exhibits a peak specific capacitance of 67.7 F/g at a current density of 4 mA/cm², a power density of 717.4 W/kg, and an energy density of 25.6 Wh/kg, maintaining 84.5% stability over 5000 cycles. The straightforward synthesis of CNCZO on multiple substrates presents a promising route for the development of flexible, high-performance energy storage devices. Full article

W-Mo-Cu composites show promise for advanced applications, but their properties require optimization. In this study, a novel approach utilizing Cu-coated graphene (Cu@Gr) reinforcement with skeleton relative density adjustment was employed to tailor the microstructure and properties of W-Mo-Cu composites fabricated via infiltration sintering (1300 °C, 1.5 h). The results revealed that Cu@Gr significantly promoted sintering densification, modified the phase composition, and enhanced the properties of the composite. Specifically, the addition of 0.4 wt.% Cu@Gr resulted in a relative density of 98% for the composite, representing an 8% increase compared to the material without Cu@Gr. Furthermore, when higher amounts of Cu@Gr were incorporated, the composite consistently exhibited a high degree of densification. In addition to the primary W, Mo, and Cu phases, molybdenum carbide, Mo₂C, was formed at 0.4 wt.% Cu@Gr, with its content rising proportionally to graphene dosage. Notably, the composite containing 0.6 wt.% Cu@Gr exhibits the highest thermal conductivity and electrical conductivity, showing 64% and 73% increases, respectively, versus Cu@Gr-free samples. Additionally, although W-Mo green compact density variations (73–85%) did not compromise graphene-induced densification, a higher green compact density reduced the thermal/electrical conductivities but increased the hardness. These findings demonstrate that controlled Cu@Gr incorporation and green compact optimization synergistically improve the properties of W-Mo-Cu composites, providing insights into high-performance material design. Full article