Search Results (2,241)

This study investigates the impact of ultrasonic treatment on the deagglomeration of aggregates of single-walled carbon nanotubes (SWCNTs) and reduced graphene oxide (rGO). The aim of the research is to enhance the electrical conductivity of a biopolymer hydrogel designed for coating metallic neurostimulation electrodes. Biocompatible coating materials are essential for the safe long-term function of implants within the body, enabling the transmission of nerve impulses to external devices for signal conversion and neurostimulation. Dynamic light scattering (DLS) was employed to monitor the dispersion state, in conjunction with measurements of specific electrical conductivity. The mass loss and swelling capacity were evaluated over an 80-day period to account for the effects of degradation during in vitro studies. Samples of flexible–elastic hydrogels for electrodes with complex geometry were formed by the photopolymerization of a photopolymerizable medium, similar to a photoresist. Analysis of the dependence of temperature and normalized optical transmittance on the duration of laser photopolymerization made it possible to determine the optimal polymerization temperature for the photopolymerizable medium as −28 °C. This temperature regime ensures maximum reproducibility of hydrogel formation and eliminates the presence of unpolymerized areas. The article presents a biopolymer hydrogel with SWCNTs and rGO nanoparticles in a 1:1 ratio. It was found that sufficient specific electrical conductivity is achieved using SWCNTs with a characteristic hydrodynamic radius of R = 490 nm and rGO with R = 210 nm (sample Col/BSA/CS/Eosin Y/SWCNTs (490 nm)/rGO 4). The photopolymerized hydrogel 4 demonstrated sufficient biocompatibility, exceeding the control sample by 16%. According to the results of in vitro studies over 80 days, this sample exhibited moderate degradation of 45% while retaining its swelling ability. The swelling degree decreased by 50% compared to the initial value of 170%. The presented hydrogel 4 is a promising coating material for implantable metallic neurostimulation electrodes, enhancing their stability in the physiological environment. Full article

This paper introduces a similarity index aimed at modeling psychological well-being through a set-theoretic formalization of self–ideal alignment. Inspired by Tversky’s feature-based model of similarity, the proposed index quantifies the degree of overlap and divergence between the current self-perception and the ideal self, each represented as a vector of signed attributes. The formulation extends traditional approaches in Personal Construct Psychology by incorporating directional and magnitude-based comparisons across constructs, and its mathematical properties can be expressed within a fuzzy similarity space that ensures boundedness and internal coherence. Unlike standard correlational methods commonly used in psychological assessment, this model provides an alternative framework that allows for asymmetric weighting of discrepancies and non-linear representations of similarity. Developed within the WimpGrid formalism—a graph-theoretical extension of constructivist assessment—the index offers potential applications in clinical modeling, idiographic measurement, and the mathematical analysis of dynamic self-concept systems. We discuss its relevance as a generalizable tool for quantitative psychology, and its potential for integration into computational models of personality and self-organization. Full article

To address the issue of microstructure damage and stability deterioration of coal pillar dams in underground coal mine reservoirs caused by long-term exposure to highly mineralized mine water, this study conducts indoor simulation experiments to investigate the evolution of coal microstructures under immersion in salt solutions with varying mineralization degrees (1000–2000 mg/L). Changes in solution chemical parameters are monitored through dynamic water quality analysis, while the pore-fracture structure of coal is quantitatively characterized using scanning electron microscopy (SEM) and a pore-crack analysis system (PCAS). Results indicate that with increasing mineralization, solution pH initially decreases due to H⁺ release from pyrite and siderite oxidation, followed by a slight recovery in later stages owing to the buffering capacity of HCO₃⁻. The trends of TDS and EC are consistent, initially slightly decreasing due to ion adsorption, and then rising with the dissolution of minerals in the later stage. The continuous decline in ORP indicates a progressive enhancement in the solution’s reducing potential. Microstructural observations reveal that after immersion in highly mineralized solutions, the coal matrix undergoes more severe fragmentation, with increased pore quantity and irregular pore morphology, and the fracture network becomes more developed and interconnected. Quantitative analysis further demonstrates that, with increasing mineralization, the proportion of large pores (>24 μm) significantly rises; the fractal dimension first decreases and then increases; the rise in probability entropy reflects enhanced spatial disorder in pore arrangement; and the pore area ratio increases. The research results provide a theoretical basis for the long-term stability evaluation and safety control of coal pillars in highly mineralized mine water environments. Full article

The effects of Ce₂O₃ and CaF₂ on the microstructure of silicate-based mold flux were investigated using an integrated approach combining molecular dynamics (MD) simulations with viscosity testing, SEM-EDS, and XRD analysis. The structural origin of changes in viscosity and crystallization behavior was revealed. It was found that the joint addition of CaF₂ and Ce₂O₃ to the silicate melt leads to a synergistic effect; CaF₂ acts as a diluent within the silicate network, while O²⁻ introduced by Ce₂O₃ promotes the depolymerization of the complex [SiO₄]⁴⁻ network. As a result, highly polymerized structural units (Q², Q³, and Q⁴) transform into less polymerized ones (Q⁰ and Q¹), reducing the overall degree of polymerization and enhancing slag fluidity. Moreover, the preferential formation of [SiO₄]⁴⁻–Ce³⁺–F⁻ and [SiO₄]⁴⁻–Ca²⁺–F⁻ coordination structures replaces the original [SiO₄]⁴⁻–Ce³⁺ and [SiO₄]⁴⁻–Ca²⁺ linkages. This structural rearrangement facilitates the formation of low-melting-point phases during cooling, thereby suppressing the crystallization tendency and improving the stability of viscous properties of the mold flux. These findings provide theoretical insight for the design of high-performance fluxes used in rare earth-containing steel continuous casting. Full article

Hydrophilic interaction liquid chromatography (HILIC) is widely used for the analysis of glycans and oligosaccharides, yet the molecular basis of retention remains incompletely understood. In this study, we investigated dextran ladders labelled with 2-aminobenzamide (2-AB) and Rapifluor-MS™ (Waters, Milford, MA, USA) across a wide range of degrees of polymerization (DP 2–15), temperature conditions (10 °C to 70 °C), and gradient programs using a Acquity™ Premier Glycan BEH Amide column (Bridged Ethylene Hybrid, Waters, Milford, MA, USA). Van’t Hoff analysis revealed distinct enthalpic and entropic contributions to retention, allowing identification of a mechanistic transition from enthalpy-dominated docking interactions at low DP to entropy-driven dynamic adsorption at higher DP. This transition occurred reproducibly between DP 4–6, depending on the fluorescent label, while gradient steepness primarily influenced the location of the minimum enthalpy. Molecular dynamics simulations provided additional evidence, showing increased conformational flexibility and end-to-end distance variability for longer oligomers. This finding is consistent with entropy-dominated adsorption accompanied by displacement of structured interfacial water. Together, these results establish a molecular-level framework linking retention thermodynamics, conformational behavior, and solvation effects, thereby advancing our mechanistic understanding of glycan separation in HILIC. Full article

Evaluating the relationship between dynamic carbon emission intensity (CEI) and high-quality economic development (HQED) provides crucial insights for advancing national strategies focused on ecological preservation and sustainable high-quality development. This study employed an integrated analytical framework that combines the entropy-weight TOPSIS model, the coupling coordination degree (CCD) model, the spatial autocorrelation, and a two-way fixed effects model to examine the spatiotemporal patterns and influencing factors of carbon emissions in the Yangtze River Basin from 2010 to 2022. The results indicated that: (1) Temporal analysis revealed a consistent annual decline in CEI levels, coupled with steady improvements in HQED. The coordination between these two systems was reflected in the estimated CCD, and it showed an upward trend, with the lower reaches experiencing the most rapid progress in coordination. (2) Spatial analysis revealed a polycentric development pattern, with Shanghai serving as the central core, and other metropolises such as Nanjing and Hangzhou acting as secondary cores. The high–high agglomeration area has been progressively expanding each year. (3) Analysis of influencing factors revealed that their impacts diminished in the following order: human capital, economic development, urbanization, green innovation, government support, industrial structure, and openness. Each of these influencing factors demonstrated distinct spatiotemporal heterogeneity, varying in their impact across different regions and time periods. The study finally provided recommendations, emphasizing the need for coordinated development strategies in the YREB, taking regional dynamics into account, and promoting green economic transformations while ensuring ecological and environmental sustainability. Full article

This paper presents the effect of the isocyanate index of polyurethane foams on the properties of repolyols and rebiopolyols obtained through glycolysis and on the foaming process of the new polyurethane systems. An FTIR spectral analysis confirmed that as the isocyanate index decreased, the intensity of the bands’ characteristic of urethane and urea bonds also decreased, indicating a lower proportion of carbonyl groups and hard segments in the polymer structure. Simultaneously, an increase in the hydroxyl number of the repolyols and the rebiopolyols was observed, along with a decrease in their viscosity and average molar masses. Both effects are consequences of a lower degree of cross-linking in the parent foams. An analysis of the foaming process using a Foamat apparatus revealed that the viscosity and the molar mass of the repolyols and the rebiopolyols significantly affected the system’s reactivity, maximum reaction temperature, and the time required to reach it. Differences in foaming dynamics resulted in different cellular structures of the foams, their apparent density, and mechanical properties. The foams obtained from the repolyols derived from foams with a lower isocyanate index exhibited a lower degree of cross-linking and a lower strength, while the foams with the rebiopolyols tended to shrink. The intensity of the shrinkage was limited by a higher degree of cell openness. These results confirm the crucial role of the properties of repolyol and rebiopolyol in shaping the reactivity, morphology, and properties of final polyurethane foams, providing a basis for designing new, sustainable polyurethane systems. Full article

This study examined how meal frequency under isocaloric conditions affects triglyceride accumulation in adipocytes, focusing on the role of insulin dynamics. Using a mathematical model of carbohydrate–lipid metabolism, we simulated feeding regimens from one to eight meals/day while holding calories and macronutrient ratios constant. A simplified model allowed independent variation in insulin peak amplitude, width, and overlap Results show that, relative to thrice-daily feeding (the reference regimen with stable triglyceride content over one month), infrequent meals (1–2/day) reduce, while frequent meals (5–8/day) increase triglyceride accumulation—most strongly in healthy individuals and attenuated in type 2 diabetes, as parameterized from the literature. Crucially, fat accumulation correlates not with average insulin levels but with its dynamic profile. Metabolic flux analysis revealed that triglyceride accumulation is driven not by changes in synthesis rate but by suppression of lipolysis, which depends on the amplitude, duration, and degree of overlap of insulin peaks. Thus, fat mass is shaped not only by caloric intake but by meal timing, which defines the insulin signal’s temporal structure. These findings highlight that insulin dynamics—not mean concentration—govern lipid metabolism, urging dietary guidelines to account for meal pattern, not just composition or total energy. Full article

Against the backdrop of China’s slowing urbanization and increasing regional disparities, existing research on the spatiotemporal evolution and multidimensional drivers of urban–rural transformation (URT) requires further elaboration, particularly regarding county-level differentiation and the dynamic interactions among these drivers. This study integrates spatiotemporal hot spot analysis with a multi-factor geographical detector model to systematically examine China’s URT from 1990 to 2023. The findings reveal the following: (1) The area of urban–rural construction land increased by 149.54% overall from 1990 to 2023, but the annual average growth rate dropped sharply to 4.32% during 2000–2023, indicating overall deceleration in spatial expansion. (2) Significant structural adjustments occurred at the county level: the proportion of counties with high spatial expansion degree decreased by 20%, while counties experiencing spatial contraction increased by 6%, suggesting that growth dynamics have become increasingly concentrated in limited counties. (3) Spatially, a clear “northern contraction and southern expansion” divergence emerged, which was primarily driven by the synergistic effects of policy reorientation, market-driven factor mobility, and differential natural endowments. (4) Expanding counties benefited from urban agglomeration plans, population influx, industrial upgrading, and favorable terrain, whereas contracting counties were constrained by rigid ecological and farmland conservation policies, population outmigration, undiversified industries, and topographical limitations. These findings provide an important premise for formulating feasible policies on differentiated spatial governance and urban–rural sustainable development. Full article

To improve recognition accuracy, convergence speed, and numerical stability in estimating the road adhesion coefficient for distributed-drive electric vehicles, a nonlinear seven-degree-of-freedom vehicle dynamics model was developed based on a modified Dugoff tire model. Using the Unscented Kalman Filter (UKF) as a foundation, a Square-Root Unscented Kalman Filter (SR-UKF) algorithm was derived through covariance-square-root processing and Singular Value Decomposition (SVD). A co-simulation platform was built with CarSim and Simulink, and a vehicle speed-following model was developed for simulation analysis. The results show that the SR-UKF algorithm for road identification consistently maintains matrix positive definiteness, ensures numerical stability, speeds up convergence, and fully utilizes measurement information. Simulations under various road conditions (high-adhesion, low-adhesion, split-μ, and opposite-μ) and driving scenarios demonstrate that, compared to the traditional UKF, the SR-UKF converges faster and provides higher estimation accuracy, enabling real-time, accurate estimation of the road adhesion coefficient across multiple scenarios. Final results confirm that the SR-UKF exhibits excellent estimation accuracy and robustness on low-adhesion surfaces, confirming its superiority under high-risk conditions. This offers a dependable basis for improving vehicle active safety. Full article

Microplastics (MPs) and perfluorooctanoic acid (PFOA) are ubiquitously present in agroecosystems, which can cause varying degrees of environmental damage. This study reports the investigation of the effect of MPs on PFOA adsorption by soil. A comprehensive analysis was performed on the adsorption–desorption dynamics of PFOA by MPs and soil under different conditions. The surface morphology of MPs and their interaction with PFOA were characterized. Irregularly shaped MPs facilitated accurate simulation of real-world conditions, influencing the adsorption quantity of PFOA in soil. Additionally, the peak intensity of various preadsorption and post-adsorption MP functional groups was altered, indicating that MPs augmented PFOA adsorption. The kinetics of PFOA adsorption followed the quasi-second-order reaction, and the isotherm data aligned well with the Freundlich model. This study reveals the mechanism by which the co-sorption of PFOA and MPs in agroecosystems affects their respective environmental behaviors, providing basic research data for the control of pollutants in agroecosystem soil. Full article

Controllability metrics based on system Gramians have been widely adopted to provide quantitative measures of the degree of controllability (DoC) and the disturbance rejection capability (DoDR) of dynamical systems. While steady-state Gramian formulations offer closed-form tractability, they are not applicable when rigid-body modes are present, as the associated poles at the origin cause the conventional Gramians to diverge. This paper presents a novel steady-state DoDR metric for linear time-invariant systems with a rigid-body mode. By block-diagonalizing the dynamics through a similarity transformation and analyzing the asymptotic behavior of the Gramian matrices, we derive an exact closed-form expression for the steady-state DoDR. The resulting formulation is numerically stable and enables systematic evaluation of disturbance-rejection capability even in the presence of a rigid-body mode. The proposed metric is validated using a mass–spring–damper chain model, where its effectiveness is demonstrated in actuator placement problems. The results show that the metric not only remains computationally well-posed but also provides physically meaningful interpretations consistent with modal characteristics. This study establishes a foundation for extending disturbance-rejection metrics to systems with multiple rigid-body modes, thereby broadening the applicability of Gramian-based controllability analysis. Full article

Cooperative and Autonomous Vehicle (CAV) platoons offer significant potential for improving road safety, traffic efficiency, and energy consumption, but maintaining precise inter-vehicle spacing and synchronized velocity under disturbances while ensuring string stability remains challenging. This paper presents a fully decentralized two-layer architecture for homogeneous platoons whose identical vehicle dynamics and information flow produce an inherent symmetrical system structure. Operating under a predecessor-following topology with a constant time headway policy, the upper layer generates a smooth velocity reference based on local spacing and relative-velocity errors, while the lower layer employs a two-degree-of-freedom (2-DOF) digital RST controller designed through discrete-time pole placement and sensitivity-function shaping. The 2-DOF structure enables independent tuning of tracking and disturbance-rejection dynamics and provides a computationally lightweight solution suitable for embedded automotive platforms. The paper develops a stability analysis demonstrating internal stability and $L_2$ string stability within this symmetrical closed-loop architecture. Simulations confirm string-stable behavior with attenuated spacing and velocity errors across the platoon during aggressive leader maneuvers and under input disturbances. The proposed method yields smooth control effort, fast transient recovery, and accurate spacing regulation, offering a robust and scalable control strategy for real-time longitudinal motion control in connected and automated vehicle platoons. Full article

The main challenge for the scientific community is to mitigate climate change impacts while reducing energy consumption, without compromising comfort and quality of life. Buildings in hot climates require specific design strategies to limit the effects of extreme weather and heat waves. Standardized modern buildings, often unsuitable for hot and arid climates, lead to high energy consumption, mainly due to cooling systems, causing both discomfort and energy inefficiency. Previous studies have shown that solutions inspired by local vernacular architecture are often more effective than conventional construction techniques. This paper investigates the thermal response and discomfort intensity in two building models exposed to various climate scenarios: a typical modern residential building and a bioclimatic vernacular-inspired building. The analysis is conducted through dynamic thermal simulations under current as well as future medium- and long-term climate change scenarios. The study evaluates the buildings’ ability to adapt to future environmental changes, an aspect that has not yet been studied in depth. Results show that contemporary buildings experience significantly higher levels of thermal discomfort than vernacular buildings under both present (TMY) and future (SSP1-2.6 and SSP5-8.5, 2080) climate conditions. Results show that under the present climate, the vernacular building exhibits about 22% fewer discomfort hours than the contemporary one and roughly half the overheating integrated degree-hours. Under future scenarios, overheating increases by 25.8% to 67.7% in the contemporary building and 36.1% to 89.6% in the vernacular building, yet the vernacular building consistently maintains substantially lower discomfort levels. Overall, vernacular inspired envelopes remain more resilient to warming in all scenarios, but additional adaptation measures are required to ensure acceptable summer comfort by late century. Full article

Potatoes, possessing the characteristics of being suitable for food crop, vegetable, and fodder use, have become an important supplementary product for ensuring food security and vegetable supply. Their price fluctuations play a significant role in regulating production and consumption. Against the backdrop of establishing a unified national market, studying potato price fluctuations from a spatial perspective is crucial for scientifically and systematically understanding the patterns of China’s potato market. This study employs Ensemble Empirical Mode Decomposition, Spatial autocorrelation and Vector Autoregression models to analyse spatial variations and inter-regional transmission mechanisms in China’s potato price fluctuations, utilising wholesale market price data from January 2014 to December 2024 across diverse regions. Findings indicate distinct spatial patterns in potato price dynamics with significant inter-regional interactions. The Northern Crop Region exhibits predominantly short-term, high-frequency fluctuations, whereas the Central Crop Region, Southern Crop Region, and Southwestern Crop Region are characterized by long-term, low-frequency fluctuations. Potato prices in China exhibit significant spatial heterogeneity, and potato price fluctuations at both national and regional levels are primarily influenced negatively by those in other regions. The degree of interactive influence between potato prices across regions exhibits considerable variation, with the Central China crop region holding a certain degree of dominance in the national market. Based on these findings, policy recommendations are proposed, including strengthening tiered and regional monitoring and analysis of potato prices, standardizing inter-regional transmission pathways for potato prices, and guiding the formation of a complementary regional structure for potato production. Full article