Search Results (608)

Microsegregation in cast materials is important to their solidification, solid-state transformation, microstructure and material properties. This work studies quantitatively the microsegregation of Si, Mn, Cu, Sn, and P in graphitic cast irons using an electron microprobe with wavelength dispersive spectrometry. The alloys contain [mass%] C: 3.86, Si: 2.59, Mn: 0.64, P: 0.03, S: 0.01, Sn: 0.098, Cu: 0.84, Mg: 0.065, include graphite morphologies ranging from ductile iron to compacted graphite iron and solidified with a solidification time of 10 min. Concentration maps are presented, showing that microsegregation patterns provide detailed information about the solidification chronology of the metal matrix. Sequencing the measurements into concentration profiles showed that, despite large differences in microstructure and cooling curve characteristics, the severity of microsegregation was similar in the studied materials. Scheil simulation of concentration profiles provided decent prediction of concentration profiles, given appropriate thermodynamic data. Numerical simulation of isothermal diffusion suggested that, for about 10 min of solidification time, diffusion in austenite mainly affected the last 10% of the matrix to freeze. Effective partition coefficients extracted from the concentration profiles varied slightly through solidification. The estimated mean effective partition coefficients for the first 90% of the alloy to freeze are ${\overline{k}}_{Si}^{\gamma /L}=1.124\pm 0.006$, ${\overline{k}}_{Mn}^{\gamma /L}=0.696\pm 0.008$, ${\overline{k}}_P^{\gamma /L}=0.15\pm 0.03$, ${\overline{k}}_{Sn}^{\gamma /L}=0.50\pm 0.02$, ${\overline{k}}_{Cu}^{\gamma /L}=1.35\pm 0.01$, where $\pm$ indicates standard deviation. Full article

In this work, ZnO, WO₃, and MgO were doped into InSnZnO (ITZO) films via co-sputtering to enhance the mobility and stability of ITO-based thin film transistors (TFTs). ITZO, InSnWO (ITWO) and InSnMgO (ITMO) films were fabricated, and the effect of cation dopants on the oxygen stoichiometry in ITO films was investigated. We further discussed their influence on the electrical parameters of corresponding TFTs, including threshold voltage ($V_{\mathrm{th}}$), subthreshold swing (SS), and field-effect mobility (${\mu }_{\mathrm{FE}}$). Additionally, the positive and negative bias stress stability of these devices was evaluated. The results demonstrate that ITWO TFTs exhibit superior stability despite a reduction in mobility. This is attributed to the high electronegativity of W⁶⁺ and the strong W-O bonding, which effectively mitigate the formation of oxygen vacancies and suppress the adsorption of impurities at the back channel. The findings provide valuable insights for the material design of high-performance TFTs. Full article

In this study, we investigate the optimization of ring spinning parameters affecting key yarn quality characteristics, including yarn tension, cop diameter, and end breakage. Experiments were conducted on cotton–polyester yarn using three process variables: traveler mass (60, 67.5, and 75 mg), spindle speed (12,900, 13,300, and 13,700 min⁻¹), and doff stage (43, 111, and 179 mm). A two-stage optimization method was applied: we used the Taguchi method to optimize individual responses, while a normalization-based composite scoring approach was used to integrate them to determine globally optimal ring spinning parameters under differing response-specific conditions. The results show that traveler mass is the dominant factor influencing yarn tension, contributing 65.48% and 73.29% of variation at the bottom and top ring rail positions, respectively. Cop diameter is primarily governed by doff stage, contributing 89.43% of total variance (ANOVA), with the intermediate level (111 mm) yielding the highest mean diameter and the most favorable S/N ratio. The yarn breakage rate is mainly affected by doff stage (57.26%) and spindle speed (41.89%), with minimum breakage observed at moderate spindle speed and mid-level doff stage. The global optimal parameter combination (60 mg traveler mass, 12,900 min⁻¹ spindle speed, and 111 mm doff stage) achieved balanced multi-response performance. The framework demonstrates strong predictive capability (R² > 0.991) and enables optimization. Full article

Coffee oil, an increasingly recognized yet underutilized byproduct of spent coffee grounds, has attracted attention due to its diverse lipid composition and minor components. This study systematically investigated the lipid characteristics of coffee oils extracted from both Arabica and Robusta spent coffee grounds subjected to varying roasting degrees. Comprehensive analyses were conducted, mainly regarding oil yield, acid and peroxide values, fatty acid profiles, sn-2 positional fatty acid distribution, triacylglycerol composition, tocopherol content and total Folin-reactive compounds, as well as squalene and sterol profiles. The selected Arabica samples generally showed higher oil yields than Robusta samples, with oil contents ranging from 12.13% to 15.14% and 10.10% to 13.01%, respectively. Arabica coffee oils showed relatively high total tocopherol levels, ranging from 930.35 to 1495.37 mg/kg, whereas Robusta coffee oils ranged from 637.69 to 867.21 mg/kg. Total Folin-reactive compounds varied among samples and should be interpreted as composition-related indicators rather than direct evidence of antioxidant function. In contrast, Robusta coffee oils contained much higher levels of squalene and total sterols, ranging from 97.00 to 170.37 mg/100 g and 787.29 to 1007.92 mg/100 g, respectively. Chemometric analyses showed distinct grouping patterns among the selected coffee oil samples. In the present sample set, the overall lipid profiles were more closely associated with the Arabica and Robusta sample groups than with the assigned roasting levels. These results provide compositional information for the potential use of Arabica coffee oil as a tocopherol- and Folin-reactive compound-rich lipid ingredient. Robusta coffee oil may be further evaluated for applications requiring higher levels of squalene, phytosterols, and relatively saturated lipid structures. This study provides novel insights into the compositional complexity of coffee oil and supports its targeted valorization across various industries. Full article

This study provides a comprehensive phytochemical and biological evaluation of Acacia nilotica and Acacia seyal samples collected from Khartoum State, Sudan. Methanolic extracts of A. nilotica leaves (SN), A. seyal leaves (TL), and A. nilotica seeds (S) were evaluated for total phenolic content (TPC), total flavonoid content (TFC), antioxidant activity (DPPH radical scavenging and reducing power), and antimicrobial activity against selected pathogenic microorganisms. High-performance liquid chromatography coupled with diode array detection (HPLC-DAD) was used to identify and quantify individual phenolic compounds. The SN sample exhibited the highest TPC (287.527 mg GAE/g), DPPH scavenging activity (96.815%), and reducing power (2.356), whereas TL showed the highest flavonoid content (155.296 mg QE/g). All samples demonstrated considerable antifungal activity against Candida albicans, while antibacterial activity varied according to species and extract type. HPLC-DAD analysis revealed the presence of major phenolic compounds, including naringenin, gallic acid, catechin, and methyl gallate, with notable variations among the investigated samples. In addition, several unidentified peaks were observed in the chromatographic profiles, suggesting the presence of additional phytochemical constituents under the applied analytical conditions. A strong positive correlation was observed between total phenolic content and antioxidant activity (R² > 0.97), indicating the possible contribution of phenolic compounds to the observed bioactivity. Overall, this study provides further insight into the relationship between phenolic composition and biological activity in Acacia species and highlights their potential as natural sources of bioactive compounds for pharmaceutical and food applications. Full article

The present study extends the investigation of thermodynamic properties of phases in the silver–magnesium binary system, with particular emphasis on the κ-Ag₂Mg₅ phase, for which available literature data remain scarce. The work is divided into two parts. The experimental section comprises the synthesis of the κ phase from high-purity Ag and Mg, followed by its characterisation using scanning electron microscopy (SEM) and X-ray diffraction (XRD). The synthesised material was subsequently used for calorimetric determination of the standard enthalpy of formation employing the drop solution method. Measurements were carried out in two experimental series (A and B), using two different metallic solvents (Al and Sn), at temperatures of 1020 K and 689 K. The enthalpy of formation obtained in both series was −14.4 ± 0.32 and −14.5 ± 0.42 kJ/mol at., respectively. In addition, the limiting partial enthalpy of solution of liquid Ag in liquid Al was determined calorimetrically and its average value is equal 7.1 ± 0.7 kJ/mol. The theoretical part of the study involved ab initio calculations of defect formation energies. The obtained results show good agreement with available literature data and provide a consistent interpretation of the observed non-stoichiometry of the κ-phase. Full article

In this study, three SnS₂ samples with different morphologies were synthesized using a one-step hydrothermal method, and the effect and mechanism of morphology on their adsorption ability toward methylene blue (MB) were studied. XRD and SEM revealed effective preparations of SnS₂ with flake, flower-like, and granular morphologies, as well as their size variations. The BET results indicate that the specific surface areas follow the order flower-like > granular > flake. Adsorption experiments demonstrated that the morphology of SnS₂ considerably impacts their MB adsorption ability. Kinetic investigations implied that the adsorption of MB on flower-like and granular SnS₂ followed a pseudo-second-order kinetic model, with adsorption rates in the order of flower-like > granular. MB adsorption on flake SnS₂ followed the Weber–Morris model. The adsorption of MB on all three SnS₂ structures followed the Langmuir isotherm model, with the flower-like SnS₂ exhibiting the highest maximum adsorption capacity of 33.1 mg/g, which is 28.8% and 27.8% higher than that of the flake structure (25.7 mg/g) and the granular structure (25.9 mg/g), respectively. Adsorption thermodynamics indicated that the ΔG^θ for MB adsorption on all morphologies was negative, suggesting their spontaneous adsorption process. Furthermore, ΔG^θ decreased with increasing temperature, indicating that higher temperatures promote MB adsorption. In addition, both the values of ΔH^θ and the ΔS^θ for the MB adsorption on SnS₂ were in the order of flower-like > granular > flake SnS₂, suggesting that MB is more easily adsorbed on the flower-like SnS₂ than granular SnS₂ and final flake SnS₂. DFT simulations confirmed that the distinct exposed facets of the flower-like morphology yielded the strongest adsorption energies, revealing the essential structure–property relationship for designing highly efficient 2D adsorbents. This work reveals the important effect of SnS₂ morphology on its adsorption behavior and gives essential insights for the design and development of adsorbents. Full article

The SnO₂-TiO₂ binary nanocomposites’ metal oxide was synthesized by a co-precipitation method and potentially utilized for wastewater treatment applications. The average crystallite size, dislocation density, and micro strain of the synthesized nanocomposites were calculated by the Debye–Scherrer, modified Debye–Scherrer, and W–H methods. The nanocomposites exhibit a tetragonal crystal structure with 62% crystallinity. The presence of Ti–O–Ti and Sn–O–Sn bonds was identified using the FTIR technique. The surface morphology was examined during SEM and EDAX analyses. The optical properties were interpreted with the help of UV–Vis and PL spectroscopy, and the bandgap energy was ascertained. From the CV and EIS studies, the behavior of the diffusive and capacitive natures was determined. Photocatalytic studies were carried out under sunlight and UV light by degrading (cationic) malachite dye at concentrations of 10, 20, and 40 mg/L. When analyzed with seven kinetic models, it was inferred that a pseudo-second and first-order were followed under visible and UV light. The maximum degradation efficiency of 94% was achieved for the 20 mg/L dye concentration within 50 min under UV and 150 min under solar irradiation. Complete decolorization was observed for both 10 mg/L and 20 mg/L dye concentrations under both irradiations. Full article

The reaction dynamics of weakly-bound nuclear systems at near-barrier energies is a compelling topic in nuclear physics. This review summarizes decades of experimental work by the Nuclear Reaction Group at the China Institute of Atomic Energy. Using transfer reactions with the distorted wave born approximation and asymptotic normalization coefficient analyses, we confirm the first excited neutron halo (¹³C) on the $\beta$-stability line and identified new halo states in ¹²B. Total reaction cross-section measurements revealed proton halo nuclei ${}^{27}\mathrm{P}$ and ${}^{29}\mathrm{S}$, with core enlargement observed in ${}^{27}\mathrm{P}$ and ${}^{28}\mathrm{P}$. We established conditions for halo formation and delineated the proton halo existence region. In two-proton emission studies, we observed ${}^2\mathrm{He}$ cluster emission from highly excited ${}^{17,18}\mathrm{Ne}$ and ${}^{28,29}\mathrm{S}$, with ${}^{29}\mathrm{S}$ being the second such case internationally. In $\beta$-delayed decay, we discovered $\beta$2p emission in ${}^{22}\mathrm{Si}$ and determined its mass, observing isospin-symmetry breaking in ${}^{20}\mathrm{Mg}$, ${}^{22}\mathrm{Si}$, and ${}^{27}\mathrm{S}$. Decay schemes for ${}^{27}\mathrm{S}$ and ${}^{26}\mathrm{P}$ addressed the ${}^{26}\mathrm{Al}$ abundance problem. For nuclear interactions, we investigated the ${}^6\mathrm{He}$ optical potential, finding the dispersion relation inapplicable for ${}^6\mathrm{He}$ + ${}^{209}\mathrm{Bi}$, and developed notch and Bayesian methods to constrain uncertainties. For unstable nuclei, the proton drip-line systems ⁸B and ¹⁷F have been intensively studied via complete kinematics measurements of the ⁸B + ¹²⁰Sn and ¹⁷F + ⁵⁸Ni reactions, respectively. The results show that elastic breakup dominates for proton-halo ${}^8\mathrm{B}$, while inelastic breakup prevails for ${}^{17}\mathrm{F}$, with proton-rich nuclei exhibiting lower breakup probabilities than neutron-halo nuclei due to Coulomb effects. Fusion studies revealed sub-barrier enhancement in ${}^{17}\mathrm{F}$ + ${}^{58}\mathrm{Ni}$ from continuum couplings. We propose direct fusion–evaporation measurements with deflection systems integrated with breakup detection to disentangle complete and incomplete fusion channels. Full article

This study presents a comparative investigation of MgCu intermetallic compounds, CuCoMnSn Heusler alloys, and carbon steel for spur gear applications using a novel tooth contact analysis (TCA) method. The TCA employs a nonlinear two-variable equation, providing a fast and accurate computational tool for evaluating gear contact behavior. By integrating material-specific elastic properties from density functional theory (DFT) studies, the analysis predicts contact paths, stress distributions, and responses to angular misalignments. Material selection strongly influences gear performance: MgCu is promising for lightweight applications, while CuCoMnSn is better suited where mechanical performance is prioritized. The CuCoMnSn alloy also exhibits half-metallic ferromagnetic behavior, offering potential functional advantages beyond mechanical performance. These results highlight the promise of intermetallics and Heusler alloys for high-performance, misalignment-tolerant gears and demonstrate the effectiveness of combining DFT-informed material modeling with the novel TCA method for optimized spur gear design. Full article

High ammonia nitrogen stress significantly compromises the survival of Litopenaeus vannamei under low-salinity conditions. However, existing studies predominantly focus on ammonia nitrogen responses under single stressors or normal seawater salinity. The molecular regulatory mechanisms, metabolic remodeling patterns, and key pathway interactions in shrimp subjected to high ammonia nitrogen stress under low-salinity environment remain unclear. In this study, we employed integrated transcriptomic and metabolomic analyses to unveil the underlying molecular responses and metabolic biomarkers in the gills of L. vannamei to ammonia stress under low-salinity conditions. First, L. vannamei underwent low-salinity acclimation from 30‰ to 5‰ salinity and was then reared for one week to acclimate to the experimental environment. Subsequently, shrimp were treated with 42.32 mg/L ammonia nitrogen for a consecutive 96 h period. Integrated transcriptomic and metabolomic analyses elucidated the stress response patterns in the gills of L. vannamei under low-salinity ammonia nitrogen exposure. Specifically, 352, 802, and 140 differentially expressed genes (DEGs) were identified at 12 h, 48 h, and 96 h post-exposure, respectively. GO and KEGG enrichment analyses revealed that the significant DEGs were primarily enriched in six major pathways: autophagy, immune-related pathway, ABC transporter, fatty acid degradation and metabolism, metabolic pathway, and PPAR signaling pathway. Metabolomic profiling identified numerous differentially accumulated metabolites (DAMs) in both positive and negative ion modes, with significantly altered DAMs mainly consisting of organic acids and their derivatives, phospholipids, and other related metabolites. Key DAMs included taurine, guanosine, 1-palmitoyl-sn-glycero-3-phosphocholine, pseudouridine, and betaine. Integrative multi-omics analysis revealed that L. vannamei mediates stress responses by modulating five core pathways under low-salinity/high-ammonia-nitrogen dual stress: fatty acid degradation and metabolism (e.g., acyl-CoA dehydrogenase short chain (Acads), acetyl-CoA acetyltransferase 2 (ACAT2)), autophagy (e.g., autophagy-related protein 101-like (atg101)), immune regulation pathway (e.g., V-type proton ATPase subunit H-like (VhaSFD), actin-5C-like (Act5C)), metabolic pathway (e.g., molybdopterin synthase catalytic subunit-like (Mocs2B), cytochrome P450 2U1-like (Cyp2b1)), and ABC transporter (e.g., ATP-binding cassette sub-family D member 3-like (ABCD3), ATP-binding cassette sub-family B member 10 (ABCB10)). Through characterization of these core pathways, this study reveals the fundamental mechanisms by which L. vannamei responds to high ammonia nitrogen stress following low-salinity acclimation, providing a theoretical foundation for estuarine shrimp farming. Full article

Quercetin, one of the most abundant flavonoids in nature, has attracted the attention of many researchers due to its chemical and biological properties. A series of metal–quercetin complexes (Cu²⁺, Co²⁺, Zn²⁺, Sn²⁺, Al³⁺, Cd²⁺ and Mg²⁺) were synthesized and systematically characterized by Fourier transform infrared spectroscopy (FTIR), UV-visible spectroscopy (UV–Vis) and nuclear magnetic resonance (NMR). These analyses confirmed that the complexes predominantly form through coordination with the 4-carbonyl group and adjacent phenolic hydroxyls. This induces measurable shifts in the ν(C=O), ν(O–H), and π→π* transition bands relative to free quercetin. The antioxidant capacity of the complexes was evaluated using 2,2-Diphenyl-1-Picrylhydrazyl (DPPH^•) radical scavenging method, 2,2′-Azinobis(3-Ethylbenzothiazoline-6-Sulfonic Acid) (ABTS^•)⁺ radical activity, and Ferric Reducing Antioxidant Power (FRAP) assay. Several complexes exhibited higher radical scavenging efficiency than quercetin, with inhibition percentages exceeding 80% in the DPPH^• and ABTS^•+ assays. Others showed reduced activity due to the masking of redox-active hydroxyl groups during metal coordination. FRAP results corroborated these trends, indicating metal-dependent modulation of reducing power. Antimicrobial evaluation revealed that selected complexes were more active than free quercetin, particularly against Staphylococcus aureus and Candida spp., with minimum inhibitory concentrations (MICs) ranging from 75–250 μg mL⁻¹. Overall, metal complexation significantly alters the electronic structure and biological behavior of quercetin, highlighting the potential of metal–flavonoid complexes as multifunctional antioxidants and antimicrobials. Full article

The Xinqiao Cu-S polymetallic deposit is located in the Tongling ore concentration area of the Middle-Lower Yangtze River metallogenic belt. The orebodies consist of skarn orebodies and stratiform sulfide orebodies, but the genetic link between them remains controversial. In this study, magnetite was used as a proxy to systematically constrain the hydrothermal evolution from the intrusion to the contact zone and further to the stratiform orebodies. A representative drill hole (E603) was logged, and samples were systematically collected from the Jitou pluton outward to the contact zone. Composite samples from the 8–28 m interval were crushed and prepared as resin mounts for integrated TIMA automated mineralogy, BSE textural observation, and in situ LA-ICP-MS trace element analysis. Five types of magnetite (Mt1 to Mt5) were systematically identified. Mt1 occurs as inclusions within feldspar in the quartz monzodiorite. It exhibits typical magmatic magnetite characteristics and contains grid-like ilmenite exsolution, indicating crystallization during the late magmatic stage. Mt2 is distributed in the interstices of magmatic minerals, commonly showing hematitization and replacement of ilmenite exsolution lamellae by titanite. Its trace element geochemistry displays magmatic–hydrothermal transitional features. Mt3–Mt5 in the skarn and stratiform orebodies are paragenetic with retrograde alteration minerals (e.g., epidote, chlorite, and actinolite) and sulfides, and are characterized by low Ti, Al, and V contents and high Mg, Mn, and Sn contents, indicating a hydrothermal origin. From Mt3 to Mt5, (Ti + V) and (Al + Mn) decrease, while Zn and Mn increase, accompanied by a decrease in the (Si + Al)/(Mg + Mn) ratio. This reflects a trend of decreasing fluid temperature and progressively enhanced wall-rock buffering. The Mg-in-magnetite geothermometer yields relatively consistent results for Mt1–Mt3, but anomalously high temperatures for Mt4–Mt5. This suggests that the elevated Mg activity in the fluid, caused by reaction with carbonate wall rocks, can significantly influence the calculated temperatures. Therefore, this geothermometer should be used cautiously for magnetite in the outer skarn zone and interpreted in combination with other temperature constraints. The textures, paragenetic mineral assemblages, and trace element characteristics of magnetite collectively reveal a continuous mineralization process linking the skarn and stratiform orebodies at Xinqiao, providing robust mineralogical and geochemical evidence for the contribution of Yanshanian magmatic–hydrothermal activity to the stratiform mineralization. Full article

In this study, Sn and Ni powders were incorporated into the flux core of brass brazing filler metals, with alloying achieved via in situ synthesis during brazing. The effects of Sn/Ni single and composite additions on the microstructure, melting characteristics, wettability on Q235 steel, and tensile strength of corresponding brazed joints were systematically investigated. Sn addition increased the β-phase fraction, reduced the solidus temperature, and significantly improved wettability—with a maximum unit spreading area of 4.22 mm²/mg at 20 wt.% Sn (2.85 times that of the Sn/Ni-free baseline). However, coarse β-phase grains and their transformation to brittle β′-phase at room temperature resulted in no enhancement of joint tensile strength. Ni addition expanded the α-phase region, refined grains, and induced solid solution strengthening of the α-phase matrix; joint tensile strength peaked at 501 MPa at 20 wt.% Ni (65% higher than the baseline). Excessive Ni (≥40 wt.%) deteriorated wettability due to reduced molten superheat, and 50 wt.% Ni caused α-phase over-strengthening and embrittlement, leading to a sharp strength drop to 214 MPa. The composite addition of 3 wt.% Sn + 10 wt.% Ni reconstructed the filler metal into a refined, uniform grid-like (α + β) dual-phase structure without new phase formation, realizing synergistic optimization of wettability and mechanical properties. The co-added sample exhibited optimal performance, with a unit spreading area of 4.51 mm²/mg and joint tensile strength of 584 MPa (206% and 93% higher than the baseline, respectively). This improvement was attributed to the coupling of uniform stress dispersion by the grid-like microstructure and dual-element functional complementation (Sn for wettability and β-phase strengthening; Ni for grain refinement and α-phase strengthening). This work provides a feasible alloying modification strategy for brass flux-cored brazing filler metals, and the revealed microstructure-performance regulation mechanism offers a valuable reference for developing high-performance brass brazing filler metals. Full article

Perovskite possess tunable crystal structures that enable the creation of active sites favorable for CO₂ adsorption and activation through appropriate doping, while their electronic structures facilitate electron transfer during catalytic reactions. In this study, BaSnO₃ was modified by substituting 4% of Ba with Mg to obtain Ba_0.96Mg_0.04SnO₃ via a co-precipitation method. Structural and physicochemical characterization (ICP, XRD, SEM-EDS, BET) revealed that Mg doping reduced particle size, increased specific surface area by 26%, and enhanced oxygen storage capacity by 6.1%. The doped catalyst also exhibited improved thermal stability, with smaller losses in surface area and oxygen storage after 1200 °C thermal aging. CO₂ adsorption tests showed higher adsorption rates and capacities, while catalytic reduction experiments demonstrated that Mg doping prolonged the catalyst’s lifetime from 24 to 40 cycles and increased maximum carbon deposition from 12.68% to 22.54%. These results indicate that Mg doping effectively enhances BaSnO₃’s catalytic activity, structural stability, and durability, making Ba_0.96Mg_0.04SnO₃ a promising candidate for CO₂ thermal reduction applications. Full article