Search Results (472)

Crude antimony containing 8–9 wt.% sodium and, in some cases, up to 25–26 wt.% sodium is obtained during the carbothermic reduction of sodium antimonate through crucible smelting. The boundaries of vapour–liquid equilibrium on the Sb–Na phase diagram were constructed to assess the possibility of using distillation processes to refine crude antimony from sodium. The boundaries of the liquid–vapour phase transitions were calculated at atmospheric pressure and under vacuum conditions (133 Pa). The presence of the incongruently evaporating compound Na₃Sb makes it possible to divide the binary Sb–Na system into two quasi-binary systems: Sb–Na₃Sb and Na₃Sb–Na. In this study, we established that the separation of antimony and sodium (the Sb–Na₃Sb system) using distillation at atmospheric pressure is technically difficult because of the high boiling temperatures of the melts in the Sb–Na₃Sb system (1635–2617 °C) and the very narrow temperature range of the vapour–liquid equilibrium field under vacuum. Molten sodium and trisodium antimonide (the Na₃Sb–Na system) can be separated both at atmospheric pressure and under vacuum when the sodium concentration in antimony exceeds 90 at.% Na (approximately 63 wt.%). However, the first case requires temperatures of up to 1570 °C, whereas vacuum conditions require a temperature of approximately 600 °C. Under these conditions, the vapour phase will consist of almost pure sodium, while antimony will accumulate in the still residue in the form of Na₃Sb. In this paper, we also present calculated thermodynamic functions, namely, the entropies and enthalpies of mixing and evaporation of antimony–sodium melts, which will supplement the existing database of physicochemical data. Full article

Cellulose ionogels have emerged as promising functional soft materials for flexible electronics, energy storage, and biosensing owing to their inherent biocompatibility and unique ionic conductivity. However, establishing precise structure–property relationships remains a fundamental challenge due to the complex, non-equilibrium dynamic processes—such as transient solvation, competing hydrogen-bonding networks, and mesoscopic phase separation—that occur during dissolution and gelation. Traditional static and post-mortem characterizations fail to capture these spatiotemporally dynamic behaviors, creating a critical knowledge gap. To overcome this bottleneck, the integration of real-time in situ/operando characterization techniques with multiscale computational simulations has established a novel, synergistic paradigm. This review comprehensively synthesizes recent advances in decoding the multiscale architectures of cellulose ionogels. We systematically analyze how molecular-scale calculations and time-resolved vibrational/electronic spectroscopies reveal interfacial solvation mechanisms and dynamic bond cleavage/reconstruction. We further evaluate how mesoscopic scattering, nanomechanical mapping, and rheological tools resolve network topology and structural heterogeneity. By bridging these multiscale diagnostics with macroscopic transport and mechanics, the dynamic coupling/decoupling mechanisms governing ionic conductivity, mechanical toughness, and thermal stability are critically decoded. Finally, key technical bottlenecks and future trajectories—including physics-informed machine learning, operando multi-field coupling probes, and AI-driven inverse material design—are outlined, providing theoretical guidelines and technical blueprints for next-generation sustainable ionogels. Full article

Glass wool provides a lightweight fibrous framework with inherent thermal-insulation capability, yet its direct use in hydrophobic monolithic aerogels has received comparatively limited systematic investigation. Here, glass wool fiber (GWF)/poly(vinyl alcohol) (PVA) aerogels were fabricated by freeze-drying followed by vapor-phase methyltrimethoxysilane (MTMS) modification. A composition matrix of 1.0–3.0 wt.% GWF and 0.10–1.00 wt.% PVA was evaluated to determine composition-dependent changes in density, calculated porosity, wettability, compressive response, thermal conductivity, crude-oil absorption, uptake kinetics, and cyclic reusability. The aerogels exhibited densities of 0.014–0.046 g/cm³, calculated porosities of 97.68–99.39%, water contact angles of 131.0–141.3°, thermal conductivities of 32.1–38.5 mW/m·K, and compressive stress at 50% strain up to 146.20 kPa. Crude-oil absorption, defined here as predominantly physical uptake and retention within the porous fibrous network, ranged from 18.86 ± 1.50 to 55.12 ± 1.57 g/g. At 0.25 wt.% PVA, samples containing 1.0–3.0 wt.% GWF reached 81–91% of equilibrium uptake within 10 s. The pseudo-second-order model provided the better empirical fit without implying chemisorption. Overall, composition influenced the balance among oil uptake, mechanical resistance, cyclic reuse, and thermal insulation. Full article

People who benefit from valuable information do not always pass it on. We develop a delayed IHSCR information propagation model in which a beneficiary can either continue spreading the information or hold it after a behavioral decision lag. The key modeling distinction is that information acquisition and the subsequent sharing-or-holding decision are treated as separate behavioral stages, while information holders can also suppress active spreaders. The delayed transitions are written as outflow rates, so arbitrary nonnegative histories do not automatically preserve positivity. We therefore work with nonnegative-feasible histories and show that such histories exist near each positive equilibrium on any fixed finite interval. For zero delay, we derive the basic reproduction number, prove global asymptotic stability of the information-free equilibrium when $R_0<1$, and give Routh–Hurwitz conditions for local stability of the positive equilibrium. With the delay as a bifurcation parameter, the linearized system gives a transcendental characteristic equation and a quartic frequency equation. The critical delay is recovered from an atan2-based phase condition, and the transversality condition identifies the first spectral stability switch. For the stability-switching parameter set, an independent characteristic-root computation verifies a unique simple crossing, and a characteristic-matrix normal-form calculation gives a negative first Lyapunov coefficient, classifying the local Hopf bifurcation as supercritical with a locally orbitally stable periodic branch. We also prove the existence of a delayed optimal control on the nonnegative-feasible set and derive the optimality system, including advanced adjoint terms. At the baseline cost weights, the computed dynamic control gives a modestly higher net objective than a numerically optimized constant-control benchmark, and this ordering persists when the relative cost ratio $c_1/c_2$ is varied from 1 to 100. A two-parameter sensitivity analysis shows how the beneficiary-to-spreader and beneficiary-to-holder transition rates shift the first critical delay. Full article

Thermodynamic concepts are increasingly used in nonlinear photonics to describe Rayleigh–Jeans thermalization, optical wave turbulence, condensation, negative-temperature states, and statistical mode locking. We ask how far this reasoning can be extended to localized structures maintained far from equilibrium by gain, loss, dispersion, and nonlinearity, using strongly chirped dissipative solitons (DSs) of the complex cubic–quintic Ginzburg–Landau equation as a model system. Their internal energy flows and separation of correlation scales connect coherent solitary waves with semi-incoherent wave kinetics, driven-open systems, and Bose–Einstein-condensation analogies. We review thermodynamic-like indicators based on spectral entropy, internal energy, effective temperature, and spectral condensation, and we relate them to dissipative-soliton resonance (DSR), stochastic mode-locking self-start, and redistribution between single- and multipulse attractors. Normal and anomalous group-delay dispersion provide complementary cases. In normal dispersion, DSR is accompanied by spectral localization, increasing scale separation, and growing multipulse accessibility; the statistical degree-count interpretation becomes meaningful only after the two scales separate and still requires ensemble calibration. In anomalous dispersion, the spectrum has extended wings, and noisy calculations reveal finite robust regions inside a larger existence domain, without an analogous thermodynamic turnover along the continuation tested. Thus, the unification is strongest at the level of the adiabatic solution and state-selection diagnostics, not an equilibrium thermodynamics. DSs thereby provide a photonic platform linking nonequilibrium thermodynamics, wave turbulence, driven condensates, and statistical phase-transition concepts. Full article

Background/Objectives: The application of organic soil amendments constitutes an important source of antibiotic residues in agricultural soils. However, studies have mainly focused on a few parent tetracyclines, whereas information on their transformation products (TPs) in organic amendments remains scarce. Therefore, this study assessed the occurrence and environmental risk of six tetracyclines and seven TPs in organic amendments. Methods: Processed livestock manures applied in the European Union (horse, poultry, and bovine manure), as well as fresh and treated sewage sludge, were analyzed using matrix solid-phase dispersion (MSPD) combined with online SPE-LC-MS/MS. Environmental risk was assessed using risk quotients (RQs) based on predicted environmental concentrations in soil (PEC_soil) calculated from the maximum measured concentrations and predicted no-effect concentrations in soil (PNEC_soil) obtained either directly from terrestrial ecotoxicity data or derived from aquatic ecotoxicity data using the equilibrium partitioning method and soil-water distribution coefficients. Results: Tetracyclines and their TPs were widely detected in both sample types, although concentrations varied according to matrix type and treatment. Overall, sludge showed higher detection frequencies and concentrations than manure. Doxycycline and tetracycline were the predominant parent compounds, reaching concentrations up to 2838 ng g⁻¹ dry weight (dw) in manure and 2892 ng g⁻¹ dw in sludge. Epimerized TPs were frequently detected and sometimes exceeded the concentrations of their parent compounds, especially epitetracycline and epioxytetracycline. Among the sludge types and treatment conditions investigated, anaerobically digested sludge showed the highest tetracycline concentrations, whereas the composted sludge sample presented the lowest concentrations. Individual RQs indicated insignificant to low ecotoxicological risk, whereas cumulative RQ (ΣRQ) values, used as conservative estimates of co-exposure to all evaluated tetracyclines and their TPs, fell within the medium-risk category for bovine manure and anaerobically digested sludge, with the composted sludge sample showing the lowest ΣRQ. Conclusions: These findings highlight the importance of including TPs in environmental monitoring and the differences in tetracycline occurrence and environmental risk to soil among the processed manure types and sludge treatment conditions investigated. Full article

Laser powder bed fusion enables the fabrication of complex Inconel 718 components, but rapid solidification produces pronounced microsegregation that complicates subsequent phase evolution. In this study, scanning electron microscopy, transmission electron microscopy, and energy dispersive spectroscopy were combined with JMatPro calculations to examine as-built microsegregation and phase behavior in laser powder bed-fused Inconel 718. The as-built alloy exhibited a continuous cellular and dendritic substructure, a high dislocation density, and interdendritic constituents with pronounced Nb enrichment and weaker local Mo enrichment. Equilibrium calculations based on the measured powder composition predicted γ formation at approximately 1350 °C and a liquid plus γ region between 1195 and 1350 °C. The calculated stability ranges of MC, δ, η, γ′, σ, M₂₃C₆, Laves, and μ phases were also identified. Comparison with the experimental observations showed that calculations using the nominal composition cannot directly represent the strongly segregated interdendritic regions formed during rapid solidification. The TTT and CCT calculations indicated that δ phase precipitation is most sensitive at approximately 900 to 1000 °C. The results clarify the distinction between local nonequilibrium phase formation and bulk phase stability and highlight the role of Nb redistribution among interdendritic constituents, the δ phase, and γ″ and γ′ precipitates. The calculated results should be regarded as a qualitative reference. Further local composition-based calculations and experimental validation are required before they can be applied to heat treatment design. Full article

Dephosphorisation in oxygen steelmaking depends on more than the equilibrium phosphorus partition ratio. It also depends on where gas, slag, metal and injected lime powder coexist while the bath is stirred. We develop a gas–slag–metal–particle reaction model for bottom-blown oxygen–CaO powder injection by coupling Euler–Euler transport of liquid steel, mixed slag, and gas with a discrete phase model (DPM) for CaO particles. The local source terms include oxygen dissolution, FeO/Fe₂O₃ conversion, CO/CO₂ buffering, competitive C/Si/P oxidation, ${\mathrm{P}}_2{\mathrm{O}}_5$ formation, $C_{2}S$–$C_{3}P$ fixation, reaction heat, and phase-wise mass conservation. Bubble swarms, dispersed slag, and emulsified metal–slag contact are represented through mean-field interfacial area densities tied to local phase fractions and mixing. Two simulated composition states have the same initial phosphorus content but different C, Si, and dissolved O levels; they are therefore compared as Case H and Case L rather than as a carbon-only test. Under the selected closures, Case H shows stronger decarburisation and CO-supported plume motion, whereas Case L retains more ${\mathrm{FeO}}_x$ and dissolved oxygen near the slag–metal interface. In both states, calculated P removal is confined mainly to locations where ${\mathrm{FeO}}_x$ supply, CaO availability, $P_2{O}_5$ generation, and $C_{2}S$–$C_{3}P$ fixation overlap. These observations are conditional on the reported parameters, a production mesh accompanied only by a two-grid qualitative sensitivity check, one time step, and the early transient considered here. Quantitative validation, systematic grid/time-step studies, closure-sensitivity tests, and controlled-composition simulations are required before the framework is used for process prediction. Full article

The service performance of austenitic stainless steel is substantially affected by the presence of residual ferrite. In this paper, as-cast 12.5% Ni 316L austenitic stainless steel billets are taken as the research object, and samples are selected from the edge, quarter-thickness, and center positions of the billet, as well as two directionally solidified specimens prepared at different withdrawal speeds. By means of metallographic analysis, Thermo-Calc thermodynamic calculations, and EBSD phase analysis, the characteristics of residual ferrite and precipitated phases in the two types of as-cast 12.5% Ni 316L stainless steel were systematically investigated. The results show that the ferrite morphologies at the edge, quarter-thickness, and center positions of the billet are granular and short-rod, skeletal, and clustered net-like and lath-like, respectively. The ferrite morphologies of the two directionally solidified specimens are similar, both being predominantly skeletal structures; the main difference is that in the high-withdrawal-speed directionally solidified specimen (No. 2), the ferrite is finer and more densely distributed. The residual ferrite contents measured at the edge, quarter-thickness, and center positions of the billet are 4.88%, 5.90%, and 8.99%, respectively; those of directionally solidified specimens No. 1 and No. 2 are 6.4% and 7.7%, respectively. For the billet, the ferrite content increases progressively from the edge to the center. Regarding precipitated phases, the edge of the billet exhibits a mixed microstructure of secondary precipitates, namely Sigma phase and Chi phase; at the quarter-thickness position, the coupled precipitation of these two phases is more pronounced; at the center, part of the ferrite has completely decomposed, with the Chi phase disappearing and only the Sigma phase remaining. In the two directionally solidified specimens, only a small amount of the Sigma phase is precipitated as secondary phases, and the ferrite remains relatively intact. Based on the morphology analysis of the ferrite structure, the solidification mode of the billet is determined to be the FA mode, which is consistent with both the Scheil calculation results and the chromium-nickel equivalent calculation results; however, it differs from the thermodynamic equilibrium solidification results obtained using Thermo-Calc. Full article

Alkali metal immobilization mediated by kaolin during wheat straw gasification was investigated using thermodynamic equilibrium calculations. Kaolin promoted the formation of stable K- and Na-bearing aluminosilicates, including feldspar, leucite, and nepheline. The controlling mechanism shifted from mineral-phase reactions below 1100 °C to a molten slag structure at higher temperatures. Increasing kaolin addition reduced the slag structure parameter R from 0.43 to 0.09, indicating enhanced network polymerization. The calculated evolution of Al-containing network units was consistent with enhanced K⁺/Na⁺ charge compensation around tetrahedrally coordinated Al, suggesting a possible structural origin for the increased thermodynamic stability of alkali metals. Gibbs free energy calculations demonstrated the improved thermodynamic stability of K and Na in the slag phase. At a kaolin addition of 5 wt.%, the K release fraction decreased by at least 29.36 percentage points relative to wheat-straw ash even at high temperatures over 1400–1600 °C. The results clarified the thermodynamic relationships among ash composition, phase evolution, and alkali partitioning during kaolin-assisted gasification. Full article

Caffeine (1,3,7-trimethylxanthine) is a widely consumed psychoactive drug and neurostimulant, yet its molecular organization and permeation behavior in lipid membranes are not fully understood. We employ microseconds-long, united-atom molecular dynamics simulations to investigate caffeine interactions with a solvated DPPC (1,2-dipalmitoyl-sn-glycero-3-phosphocholine) bilayer at its fluid phase. Caffeine molecules initially aggregate in the aqueous phase to form ordered stackings, which successively permeate into the membrane. The stacked assemblies gradually dissolve, reaching a stable dispersed state where caffeine molecules preferentially reside near the headgroup–acyl chain interface and orient parallel to the lipid acyl chains, consistent with previous experimental and simulation studies. Simulations initiated with caffeine in the membrane hydrophobic phase converge to the same equilibrium state, indicating a preferred localization at the interface region. Present simulation findings are further supported by free-energy calculations that demonstrate caffeine’s high affinity at the headgroup–acyl chain interface. Caffeine partitioning transiently and slightly reduces bilayer thickness and increases the membrane surface area while enhancing acyl chain stiffness near the hydrophilic part of the membrane. These observed trends are reproducible over different system sizes and independent simulations. Overall, this study provides atomic-level insights into the caffeine permeation process, including its effect on the lipid bilayer structure. Full article

A systematic numerical simulation and analysis of the temperature field were conducted for the laser cladding process of CuCrZr alloy onto a 316L stainless steel substrate. First, the thermal properties of the material (density, thermal conductivity, and specific heat capacity) as a function of temperature were calculated using JMatPro software. The equilibrium phase diagram of the CuCrZr alloy was obtained using Thermo-Calc, clarifying the stability of each phase and the solid–liquid phase transition ranges. Based on these findings, three-dimensional transient heat transfer models for single-layer single-pass and single-layer multi-pass cladding were established using ANSYS finite element software and a double-ellipsoidal moving heat source model. The effects of laser power on the evolution of the temperature field, peak temperature, and thermal cycling characteristics were systematically investigated. The simulation results indicate that the temperature field exhibits typical rapid heating and rapid cooling characteristics; the peak temperature increases significantly with rising laser power, and the extent of the high-temperature region expands. A combined analysis of the phase diagram and temperature field results indicates that the peak cladding temperature exceeds the complete melting temperature of the alloy, ensuring sufficient melting. This study provides a reliable theoretical foundation and data support for optimizing laser cladding process parameters, predicting the microstructure of the cladding layer, and controlling thermal stress. Full article

High-purity SiC powder is an important feedstock for SiC crystal growth, but thermal-field regulation becomes difficult during large-batch synthesis. This study examined an α-SiC powder-synthesis furnace with upper and lower induction-coil groups through numerical simulations and 70 kg synthesis experiments. A representative two-dimensional axisymmetric model was used to compare eight cases with different coil-turn or numerical power allocations. Redistributing the coil turns changed $E_1$, $E_2$, volumetric Joule heat density, $Q$, and the resulting temperature and calculated gas-phase velocity-magnitude fields. From C01 to C04, the maximum calculated temperature decreased from 2501.10 to 2359.13 K, while $\Delta T$ decreased from 242.57 to 76.20 K. Increasing the upper-coil numerical power raised the temperature level while reducing $\Delta T$ to 152.41 K. Increasing the lower-coil numerical power also raised the temperature level, but increased $\Delta T$ to 292.26 K. Equal-total-power comparisons showed that axial power allocation affected $T_{\mathrm{m}\mathrm{a}\mathrm{x}}$ and $\Delta T$. XRD identified 6H-SiC as the detected crystalline phase in both analyzed middle-region specimens, although X-ray-amorphous carbon could not be excluded. The specimens also differed in macroscopic appearance, measured impurity concentrations, and local nitrogen concentration profiles. Because the experimental conditions were maintained nominally unchanged except for the upper-coil current, these specimen-level differences may be associated with altered internal thermal conditions. Such changes may affect local equilibrium, supersaturation, and species transport, providing a possible link to the observed material differences. The numerical results identify coil-turn allocation and axial power allocation as variables for regulating the calculated furnace fields. Full article

This study investigates the possibility of using aluminosilicochrome (ASC) produced from technogenic raw materials as a potential alternative to FSC-48 ferrosilicochrome in refined ferrochrome smelting. Laboratory smelting tests were carried out in an induction furnace using alumina crucibles with a charge mass of 50 g. The two variants were compared based on the material balance, SEM-EDS analysis of the metallic and slag phases, a conditional estimate of chromium transfer to the metal, and the results of thermodynamic modeling in FactSage 8.4. It was established that a Cr–Fe metallic phase is formed when both FSC-48 and ASC are used. The average metal mass was 13.8 g for FSC-48 and 13.3 g for ASC. According to SEM-EDS data, the Cr content in the metallic phase was 70.53 and 68.64 wt. %, respectively. Aluminum introduced with ASC predominantly transfers into the slag, increasing its Al content to 20.81 wt. %. The conditional estimate of total chromium transfer from the charge to the metallic phase was 91.9% for FSC-48 and 91.6% for ASC. FactSage modeling showed higher calculated ore-derived Cr recovery for ASC under equilibrium conditions; however, excessive ASC addition increased the Si content in the metal. The obtained results confirm the fundamental possibility of using ASC as a complex reductant in refined ferrochrome smelting. Full article

This study aims to investigate the effects of slag chemical composition on the smelting reduction behavior and microstructural evolution of chromite at 1525–1550 °C, thereby providing theoretical guidance for optimizing the smelting reduction process. Through high-temperature melting experiments combined with Scanning Electron Microscope - Energy Dispersive Spectrometer(SEM-EDS) microstructural characterization and thermodynamic calculations, the influences of basicity, MgO content, and Al₂O₃ content on chromium reduction behavior, slag physicochemical properties, and spinel evolution mechanisms were systematically analyzed. The results indicate that a basicity of 1.2 effectively promotes the dissolution and reduction of chromium spinel, whereas excessively high basicity hinders the reduction process when using graphite as the reducing agent. Although increasing MgO content initially improves slag fluidity and reaction rates, it promotes the formation of a Mg-Al-rich solid product layer during the later stages of the reaction; this restricts the intra-phase diffusion of Cr³⁺ and causes the reduction process to stall. High Al₂O₃ content significantly increases system viscosity and impairs mass transfer, thereby reducing the degree of reduction. Under optimized conditions, specifically an Al₂O₃ content of 14 wt% and a temperature of 1550°C, the degree of reduction approaches 93%. Thermodynamic calculations further reveal that the efficiency of chromite smelting reduction is synergistically controlled by factors such as slag viscosity, liquid-phase behavior, and spinel equilibrium phase mass. The favorable slag composition identified in this study, basicity of 1.2, MgO content of 10 wt%, and Al₂O₃ content of 14 wt%, provides favorable physicochemical conditions for the efficient smelting reduction of chromite. Full article