Search Results (124)

Carrying out a series of fundamental studies in the field of physicochemical analysis, based on an approach that considers the phase state of alloys and accounts for the regular patterns of interaction of substances in multicomponent ores that are complex in both chemical and phase composition, makes it possible to formulate a number of scientifically substantiated practical recommendations. The aim of this work is to assess the degree of zinc sublimation from a magnesium alloy through the behavior of the Bjerrum–Guggenheim osmotic coefficient and the degree of dissociation of the congruent compound. The paper presents a method for processing phase equilibrium lines in a temperature–composition phase diagram, resulting in mathematical expressions for the liquidus and solidus lines on a unified analytical basis in the form of a semi-empirical dependence derived from the Schröder–Le Chatelier equation. Indirectly, through the Bjerrum–Guggenheim osmotic coefficient, the degree of dissociation of MgZn₂ in the Mg–Zn system was determined to range from 17% to 46%. This result is in good agreement with the conclusions of Nikolay Semyonovich Kurnakov regarding the degree of dissociation of congruent compounds inferred from the shape of the maximum on phase diagrams. For MgZn₂, this maximum is very smooth, i.e., the composition of the liquid phase changes continuously with deviation from stoichiometry, resulting in a symmetrical rounded peak. An experimental study was carried out using a SEM/EDS analytical complex to confirm the high volatility of zinc. The key zinc-concentrating phases were identified in the investigated processing products (slag, metal, and dust), which is consistent with the theoretical premises and explains the mechanism of zinc behavior during high-temperature processing of zinc-containing slags. The form of zinc occurrence in different phases was established. In the initial slag, the zinc content reaches 51.79%. In the metallic phase, zinc is detected as fine dispersed inclusions. In the collected dust (flue ducts), particles enriched in zinc up to 44.09 wt.% were identified. Full article

Understanding the absorption and desorption behavior of superabsorbent polymers (SAPs) in ionic environments is critical for their practical applications. Ion exchange between monovalent counterions within the SAP and multivalent cations (e.g., Ca²⁺) in solution not only induces macroscopic desorption but also generates non-uniform internal strain, creating a complex feedback loop with ion transport. This study establishes a phenomenological coupled model that integrates Fickian diffusion for ion transport with an elastic wave equation for SAP deformation. The coupling is realized through deformation-dependent diffusion coefficients and an ion-concentration-modulated elastic modulus, with the latter described by a first-order linear relationship over a limited range. Taking Ca²⁺ as a representative divalent cation, we systematically investigate the effects of solution concentration, SAP particle size, and ion dissociation degree. The model predicts several non-intuitive phenomena, including transient internal free Ca²⁺ concentrations exceeding the boundary concentration by up to ~15% and concentration gradient inversions for small SAP particles (radius 75 μm) at later times. Characteristic absorption time constants τ_a range from 98 s to 179 s depending on particle size and Ca²⁺ level. Simulated total Ca²⁺ uptake agrees with experimental data within an 8% mean relative error. The model is validated against macroscopic absorption/desorption curves and total Ca²⁺ uptake, while the predicted internal concentration and strain fields remain to be confirmed by spatially resolved experiments. These findings provide new mechanistic insights into the chemo-mechanical coupling in SAPs and offer guidance for their tailored design. Full article

The efficacy of working memory training (WMT) in facilitating academic achievement remains heavily debated. To resolve this efficacy paradox, the current study implemented an integrated adaptive WMT (IA-WMT) paradigm to investigate near transfer to inhibitory control (IC) and far transfer to mathematical abilities in school-age children. We assigned 89 typically developing children (M_age = 109.08 ± 3.90 months; 43 girls) to an IA-WMT group (29 students), an active control group (30 students), or a passive control group (30 students). Pretest and posttest assessments measured core working memory capacity, IC, exact calculation (EC), and approximate calculation (AC). Results revealed that six sessions of IA-WMT significantly enhanced visual–spatial and verbal working memory. Furthermore, the training induced potential near transfer to IC and asymmetric far transfer to EC, while yielding no specific gains for AC. This functional dissociation provides valuable alignment with the dual-system model of mathematical cognition. The findings suggest that far transfer may not operate as a generalized spillover effect but appears to be governed by the degree of functional overlap between trained executive processes and inherent task demands. Ultimately, organically integrated cognitive training represents a promising targeted intervention tool to facilitate cognitive and academic development during early school years. Full article

Critical illness myopathy (CIM) is linked to mechanical ventilation and complete mechanical muscle silencing in intensive care unit (ICU) patients. Limb muscles show atrophy and declined specific single fibre force through altered protein turnover and diminished myosin-to-actin ratios. A rat ICU model reproducing preferential myosin loss and specific force decline in limb muscle was used to assess myofibrillar remodelling. After 5 or 10 days of ICU intervention, single extensor digitorum longus (EDL) and soleus muscle fibres were imaged using label-free, Second Harmonic Generation (SHG) microscopy, followed by quantitative 3D morphometry. The degree and severity of deranged myofibrillar architecture was assessed through (i) 2D and 3D Cosine Angle Sums (CAS2D/CAS3D) and (ii), Vernier Densities (VD) parameters. A progressively declining myofibrillar order was seen by dropping CAS2D/3D and increasing VD values during ICU intervention, reflecting angular and axial register deviations. Effects of chaperone co-inducer BGP-15, dissociative glucocorticoid Vamorolone (VBP-15) or its parent compound Prednisolone on myofibrillar architecture were explored. Both BGP-15 and VBP-15 modulated the progression of myofibrillar disorder seen during ICU intervention alone: For soleus fibres, BGP-15 maintained structural integrity at day 5 but not at day 10, while even worsening myofibrillar order in the EDL. VBP-15 reversed atrophy at day 10 in soleus but not in EDL fibres. Our study is the first to quantify myofibrillar remodelling in limb muscle fibres during ICU intervention in 3D and provides exploratory assessment of BGP-15 and VBP-15 treatments on aberrant remodelling in CIM. Full article

Efficient recovery of long-chain dicarboxylic acids (LCDAs) from aqueous fermentation broths is a key challenge for the industrial development of bio-based LCDA production. This study evaluates liquid–liquid extraction (LLE) as a downstream recovery strategy, comparing physical extraction (PE) and reactive extraction (RE) for DCA 12, DCA 16, and DCA 18. The novelty of this work lies in demonstrating that LCDA extraction is governed by mechanisms fundamentally different from those of short- and medium-chain dicarboxylic acids. Whereas shorter chain dicarboxylic acids are mainly controlled by dissociation degree, LCDA recovery is strongly influenced by carbon-chain apolarity, low aqueous solubility, and compound losses through agglomeration, precipitation, and/or micellization. PEs enabled the selective recovery of the more hydrophobic DCA 16 and DCA 18 over DCA 12, confirming the dominant role of chain length in LCDA separation. In contrast, RE with Aliquat^®336 maximized total LCDA recovery, achieving extraction efficiencies above 85%, but with reduced selectivity. Validation in autoclaved fermentation broth from UCO feedstock confirmed the potential of Aliquat^®336 in octanol for high LCDA recovery, while revealing lower extraction efficiencies than in model mixtures due to broth matrix complexity. Overall, this study establishes LLE as a promising platform for LCDA recovery and highlights that future downstream process design must balance total recovery, chain-length selectivity, and broth-specific matrix effects. Full article

The electron localization of hydrogen molecular ions (H₂⁺) driven by a two-color field is investigated by solving the time-dependent Schrödinger equation in the non-Born–Oppenheimer approximation. The results indicate that the degree of electron localization is highly sensitive to both the time delay of the two-color field and the intensity of the control laser pulse. We compared the evolutions of both molecular nuclear and electronic wave packets under one-color versus two-color fields. It is found that a control field with a proper intensity has a slight influence on the dissociation process while significantly affecting the electron transition process. The coupling region around R = 5.2 a.u. of the control field plays an important role in the electron localization process, despite potential Stark shifts. Control field intensities in the range of 9 × 10¹² to 2 × 10¹³ W/cm² are found to be effective. Applying the control pulse with a 17 fs time delay and an intensity of 2 × 10¹³ W/cm² results in a high percent electron control efficiency of 83%. Further investigation shows that effective control of electron localization in the asymmetric dissociation can still be achieved by altering the relative phase of the two-color field while keeping the time delay constant. Full article

This study presents a thermodynamic analysis of the dissociation and association behavior of the Fe–Si system using the Bjerrum–Guggenheim osmotic coefficient. An equilibrium thermodynamic approach was applied to evaluate the Gibbs free energy, equilibrium constant, and degree of association of the congruently melting compound FeSi over a wide temperature range. The Fe–Si system was analyzed across three characteristic crystallization regions: Fe-rich, FeSi, and Si-rich. It was established that the Fe-rich region exhibits behavior approaching ideality with a nearly linear dependence of the osmotic coefficient, whereas the Si-rich region is characterized by strong deviations from ideality due to intensive association processes. The FeSi crystallization region represents a transitional regime in which association and dissociation processes occur simultaneously. The formation and partial dissociation of [Fe_xSi_y] clusters significantly affect the thermodynamic behavior of the melt. It was shown that accounting for FeSi dissociation leads to a linearization of the osmotic coefficient dependence and improves the accuracy of thermodynamic description. The proposed analytical approximations demonstrate high correlation coefficients (R² ≈ 0.99), confirming the reliability of the developed approach. The results provide a consistent thermodynamic framework for describing phase transformations and structural evolution in Fe–Si melts and can be applied to the optimization of metallurgical processes involving silicon-containing alloys. Full article

To address the issue of motion artifact interference faced by wearable ECG monitoring devices in dynamic environments, this paper proposes an adaptive motion artifact removal framework based on improved Variational Mode Decomposition (VMD). By designing a parameter self-adjustment mechanism and a multi-feature fusion mode selection strategy, the algorithm’s adaptability to non-stationary ECG signals and noise separation accuracy are enhanced. Experiments on the MIT-BIH Arrhythmia Database demonstrate that the improved VMD algorithm outperforms traditional wavelet transform, Recursive Least Squares (RLS), and conventional VMD methods in multiple performance metrics. Specifically, the signal-to-noise ratio (SNR) is improved by 5.17 dB, the Percentage Root Mean Squared Difference (PRD) is reduced to 49.13%, the correlation coefficient is increased to 0.88, and high real-time processing capability (Real-Time Processing Ratio, RTR = 22.5) is maintained, meeting the low-latency requirements of wearable devices. Moreover, case studies on pathological recordings (e.g., Wolff–Parkinson–White syndrome and third-degree atrioventricular block) reveal that the improved VMD better preserves clinically significant features such as delta waves and dissociated P waves. Furthermore, a downstream arrhythmia classification task using a CWT-CNN classifier achieves 91.67% accuracy on denoised heartbeats, which is 2.67 percentage points higher than that on raw noisy signals (89.00%), confirming the practical benefit of the proposed preprocessing for AI-based diagnosis. This study provides an effective processing solution for improving the signal quality of wearable ECG monitoring. Full article

The lithium resource reserves in Xinjiang’s Dahongliutan reach 1.1 million tons, making it one of the most representative spodumene deposits in China. Through process mineralogy analysis, the ore was identified as having inherent characteristics that control density-based separation: Coarse crystallization, a high monomer dissociation degree, and a density contrast. Based on these mineralogical characteristics, dense-medium separation experiments were conducted to investigate the mineralogically controlled separation behavior as a function of particle size and medium density. Three process flows (two-product, pressureless three-product, and two-stage, two-product) were further designed and comparatively evaluated. It indicated that the dense-medium separation efficiency is positively correlated with the monomer dissociation degree of spodumene, and the 0.5~6 mm size fraction is the optimal particle size range because it achieves a balance between ore crushing dissociation and coarse-grain dense-medium separation adaptation. Furthermore, all three dense media processes can save grinding energy, and each of them has its own advantages and disadvantages. Comprehensively considering the grade of the concentrate, recovery, the grade of the tailings, and grinding energy consumption, it is recommended to adopt a combined process of two-stage, two-product dense-medium separation and flotation. Full article

The subject concerns the determination of activation energy under dynamic conditions using two theoretical isothermal models, and subsequently experimental data, with reference to the α–T relationship matrix. In recent years, the Vyazovkin method, classified as one of the isoconversional variants, has gained the greatest recognition. Comparison was made between two isothermal models of the thermal dissociation of calcite, which in chronological terms are associated with a kinetic–nucleation reaction/process (the H-CL, as a kinetic model) and a kinetic–desorption reaction/process (the V, as a thermodynamic model). A comparison of numerical values, understood as the logarithm of the reaction/process rate with respect to temperature, shows correspondence in the temperature range up to the equilibrium temperature. The H-CL model is characterized by a strong dominance of the nucleation process relative to the chemical reaction, whereas the V model exhibits a certain type of balance resulting from the course of the chemical decomposition reaction combined with the transformation of a metastable oxide into a crystalline form. It was confirmed that both models describe the same phenomenon within the transformation process, which implies that for a constant conversion degree, the proportions of the chemical reaction and the physical process vary. Pointwise with increasing temperature, the H-CL model leads to a minimum activation energy E → 0, whereas the V model reaches a negative activation energy E < 0. In both cases, the apparent activation energy summed over the process is constant, and the assigned conversion degree, treated as isoconversional, remains fixed and corresponds to the assumed activation energy of the completed reaction/process. Several simple methods for its determination under dynamic/isoconversion conditions are used. Full article

China’s coking coal resources are scarce, and maximizing the recycling of these resources is the primary objective of coal processing and utilization. The embedding features of inorganic minerals within coking middling coal resources are an inherent factor influencing their liberation and separation efficiency. However, current research lacks a systematic investigation into how the embedding features of inorganic minerals in coking middling coal affect their liberation characteristics and flotation separation performance. This study examines three Chinese coking middling coal samples with distinct embedding features. Based on quantitative characterization of inorganic mineral embedding, grinding tests with varying durations and flotation separation tests on post-grinding products were conducted. Liberation and separation efficiencies were evaluated to explore the influence of inorganic mineral embedding on liberation degree and the subsequent impact of the liberation degree on flotation performance. The results indicate that the three coking middling coal samples with different embedding features exhibit significant differences in the dissociation behavior between inorganic minerals and organic matter. The particle size (D) of inorganic mineral phases is the primary factor influencing the liberation degree of inorganic minerals, while the complexity of intergrowth between inorganic minerals and organic matter (CIG) is a secondary factor. The CIG is the primary factor affecting the liberation of organic matter. As the liberation of inorganic minerals and organic matter increases, the separation efficiency improves for the Liuwan middling coal samples, whereas it deteriorates for the Shaqu and Changzhi samples. Full article

Metabolic dysfunction-associated steatotic liver disease (MASLD) is the leading cause of chronic liver disease worldwide, distinguished by pronounced clinical heterogeneity and a frequent dissociation between metabolic risk factors and the degree of hepatic injury. These observations, together with the limited contribution of genetic heritability, have prompted a re-evaluation of the traditional conceptual framework of the disease. In this context, the question has emerged as to whether MASLD could be, at least in part, a transmissible condition. While there is no evidence to suggest that MASLD is contagious in humans, as no data support person-to-person transmission, gnotobiotic animal studies demonstrate that human gut microbiota can transfer susceptibility to steatosis, inflammation, and systemic metabolic disturbances through immunometabolic mechanisms, independent of host genetics. In parallel, human studies involving microbiota-targeted interventions support the concept that the gut ecosystem is a modifiable determinant of metabolic and hepatic phenotypes. Crucially, these findings do not imply natural transmission of disease, but rather underscore the functional plasticity of microbiota-host interactions. This narrative review integrates epidemiological, experimental, and clinical data to explore the hypothesis that MASLD may be functionally transmissible. MASLD is increasingly recognized as an eco-biological disease, where liver disease risk is not only shaped by host genetics and environment, but also by the ecological configuration and functional outputs of the gut microbiome. This perspective redefines disease susceptibility as, in part, context-dependent and microbiota-mediated, without implying infectiousness in the traditional sense. Full article

The hydrogen gasochromic phenomenon offers a new strategy for real-time sensing technologies for hydrogen leakage to ensure hydrogen safety. However, the limited recovery kinetics impede the cycling and further practical applications. Herein, we designed a series of PtAg-decorated WO₃ nanowires via the chemical reduction deposition method, which could exhibit obvious and reversible color changes for H₂ detection. With the assistance of Ag, the oxygen adsorption and dissociation were accelerated; then, the sample could exhibit a constant rapid recovery rate. The crystalline Pt-Ag/WO₃ nanowires could attain a 50% recovery degree within 52 s, and the recovery time of the Pt-Ag/WO₃ sample was reduced to one fifth that of Pt/WO₃. This study provides a fundamental solution to the challenge of slow recovery kinetics in H₂ gasochromic crystalline materials. Full article

Designing ionic liquids (ILs) where a single functional group orchestrates a suite of enhanced properties remains a key challenge in materials science. Here, we introduce 1-butyl-3-methylimidazolium mandelate, [Bmim][Man], a novel IL where the hydroxyl group on the mandelate anion simultaneously enhances hydrogen bonding, thermal stability, antimicrobial activity, and extraction selectivity. The structure-property relationships of [Bmim][Man] were investigated through measurements of density, viscosity, and conductivity and were compared with analogous ILs. The presence of the hydroxyl group on the mandelate anion resulted in the highest density and viscosity among the series, attributed to strong hydrogen bonding and efficient ion packing. Notably, [Bmim][Man] exhibited a high molar conductivity that decouples from its high viscosity, suggesting an unusual degree of ion dissociation facilitated by the hydroxyl group. Thermogravimetric analysis revealed superior thermal stability. Furthermore, the investigated ionic liquid demonstrated a low critical aggregation concentration (CAC = 0.01982 mol·dm⁻³) in water, indicating a strong propensity for self-aggregation. [Bmim][Man] showed synergistic, enhanced antibacterial activity against E. coli and P. aeruginosa. Finally, the functional utility of this designed liquid was demonstrated in separation science, where [Bmim][Man]-based aqueous biphasic systems showed selective extraction capabilities for transition metals, a process driven by the same hydrogen-bonding and coordination interactions that define its bulk properties. These findings establish [Bmim][Man] as a promising multifunctional material where the mandelate anion concurrently dictates liquid microstructure, thermal resilience, antimicrobial performance, and application in extraction. Full article

The composite material MgH₂-EEWNi-Cr (20 wt. %) with a hydrogen content of 5.2 ± 0.1 wt.% is characterized by improved hydrogen interaction properties compared to the original MgH₂. The dissociation of the material occurs in three temperature ranges (86–117, 152–162, and 281–351 °C), associated with a complex of effects consisting of changes in the specific surface area of the material, alterations in the crystal lattice during ball milling, and changes in the electronic structure in the presence of a Ni–Cr catalyst, based on first-principles calculations. The decrease in desorption activation energy (E_d = 65–96 ± 1 kJ/mol, ΔE_d = 59–90 kJ/mol) is due to the catalytic effect of N–Cr, leading to a faster decomposition of the hydride phase. Based on the results of ab initio calculations, Ni–Cr on the MgH₂ surface leads to a significant decrease in hydrogen binding energy (ΔE_b = 60%) compared to pure magnesium hydride due to the formation of Ni–H and Cr–H covalent bonds, which reduces the degree of H–Mg ionic bonding. The results obtained allow us to expand our understanding of the mechanisms of hydrogen interaction with storage materials and the possibility of using these as mobile hydrogen storage and transportation materials. Full article