Search Results (12,833)

Conventional powdered biochar encounters severe bottlenecks in practical water treatment, such as difficult separation, easy loss, and potential secondary pollution. This work aimed to develop recyclable and high-performance adsorbents by preparing iron-doped biochar/sodium alginate composite microspheres (BC/MBC500-ALF) through Fe³⁺ cross-linking. Using corn stalk biochar and KMnO₄-modified biochar as adsorbent components and sodium alginate (SA) as a green shaping matrix, SA formed a stable egg-box hydrogel network to convert powdered biochar into uniform microspheres. Batch adsorption experiments revealed that the optimal pH for oxytetracycline (OTC) adsorption was 9, with adsorption capacities of 136.28 mg/g for BC500-ALF and 182.91 mg/g for MBC500-ALF. Kinetic analysis showed that BC500-ALF followed pseudo-first-order kinetics (R² = 0.983) dominated by physisorption, while MBC500-ALF fitted pseudo-second-order kinetics (R² = 0.994) dominated by chemisorption. The maximum Langmuir adsorption capacities at 308 K were 220.75 mg/g and 495.05 mg/g, respectively. Thermodynamic parameters confirmed a spontaneous and endothermic process. The adsorption mechanisms involved hydrogen bonding, π–π stacking, electrostatic attraction, metal-bridging complexation, and Fe–Mn oxide-mediated redox reactions. SA exerted dual functions in structure stabilization and adsorption enhancement. This composite provides an efficient and eco-friendly approach for tetracycline antibiotic pollution control in aqueous environments. Full article

The goal of laser polishing (LP) is to improve the surface quality of functional parts, components, and assemblies. LP is a complex nonlinear thermophysical process, in which laser radiation induces localized melting of a material with an initially rough surface topography. During LP, the thermodynamic state evolves dynamically due to transient melt flow, heat transfer, and rapid solidification within the laser–material interaction zone. A smooth surface is formed through the interplay between surface tension-driven flow, which promotes energy minimization, and nonequilibrium effects associated with melting and solidification. From the perspective of self-organization, LP can be interpreted as an open system driven by energy input, where complex material redistribution leads to the evolution of surface topography. In this work, the self-organization of molten material is analyzed using chaos-based descriptors, including the Lyapunov exponent, phase portrait, approximate entropy, and the Hurst exponent, calculated from measured surface topographies before and after laser polishing. The results show that LP acts as a spatial low-pass filter, reducing high-frequency surface components associated with micromilling marks, and exhibits a directional bias in material redistribution relative to the laser scanning direction. Among the evaluated descriptors, the Lyapunov and Hurst exponents demonstrate consistent behaviors, indicating their suitability as robust indicators of surface state in post-process analysis. For the investigated conditions (Inconel 718), a laser fluence of 158.3 mJ/cm² provided the best-achieved surface quality, corresponding to an improvement in surface roughness (Ra) of approximately 70% and the lowest Lyapunov exponent of 1.966 and highest Hurst exponent of 0.859. This study demonstrates that chaos-based analysis of surface topography provides a phenomenological framework for assessing process stability and surface evolution, offering a basis for thermophysics-informed development of LP in applications such as mold and die manufacturing. Full article

This study investigates the selective synthesis of α- and γ-alumina nanoparticles using plasma-induced microbubbles. Although plasma-induced bubbles provide an effective reaction environment for the synthesis of nanomaterials, precise phase control remains challenging. Herein, we demonstrate that the modulation of the pulse off time regulates the thermal environment within the bubbles. Optical emission spectroscopy revealed that a shorter off time maintains a high electron temperature, indicating substantial heat accumulation. This high-energy state promotes the atomization of the precursor mist and the subsequent growth of molten droplets, providing sufficient activation energy for the formation of the thermodynamically stable α-phase. In contrast, a longer off time leads to the formation of a metastable γ-phase because of insufficient heating and rapid quenching. These findings prove that alumina nanoparticles with desired crystal phase and size can be synthesized by controlling the thermal energy inside the plasma-induced microbubbles. Full article

This study presents a combined numerical and experimental investigation of transient multiphase compressible flow inside a profiled-rotor rotary volumetric compressor. While most existing studies rely on high-fidelity CFD approaches, a low-order thermodynamic chamber-based model implemented in MATLAB Release 2023a is proposed to predict the temporal evolution of pressure, temperature, and vapor volume fraction during the compression cycle. The model is based on mass and energy conservation applied to variable-volume control chambers and incorporates a simplified cavitation criterion derived from local pressure relative to saturation vapor pressure. An open-loop experimental test bench was developed to measure air mass flow rate, suction and discharge pressures, temperatures, torque, and shaft power under controlled operating conditions. These measurements are used to validate the numerical predictions. The results show good agreement between measured and simulated pressure levels and global performance indicators, with deviations quantified using mean absolute percentage error values remaining below 5% over the investigated operating range. The numerical analysis further reveals the occurrence of localized low-pressure zones during the suction phase, indicating incipient cavitation or microbubble formation at specific rotor positions. The proposed modeling approach provides a computationally efficient alternative to full CFD simulations and enables rapid parametric analysis of rotor geometry and operating conditions. The cavitation formulation does not aim to resolve detailed bubble dynamics or erosion mechanisms, but rather to identify cavitation tendency based on thermodynamic pressure thresholds. Full article

Sunset Yellow is a water-soluble synthetic dye resistant to degradation and stable under various conditions, posing an environmental challenge. In the present study pure chitosan hydrogel (PCH) films were synthesized, followed by the assessment of sorption capacity and recyclability compared to chitosan-based films doped with niobium oxide (CHN) or activated carbon (CHC). The aim was to promote the application of sorption methods for Sunset Yellow dye using these films as a treatment option for the pollutant, with the analysis of the effectiveness of the method and its behavior using adsorption kinetic models and thermodynamic analysis. Equilibrium was reached at 240 min for all films tested, with the adsorbed amounts ranging from 18.58 to 18.79 mg g⁻¹ at 30 °C, when the highest kinetic rate constants were observed. The pseudo-first-order kinetic model best described the experimental data, with the lowest Bayesian information criterion, Akaike information criterion, and mean absolute error values. Thermodynamic analysis indicated a spontaneous, exothermic process, with interactions ranging from electrostatic interactions in CHC and PCH to physisorption in CHN. Recycling tests showed 80% efficiency after the third cycle for all three films. These findings highlight the potential of chitosan-based films as an efficient option for removing Sunset Yellow dye from water, thus improving water quality and enhancing wastewater treatment. Full article

Hurricane Florence (2018) proved to be a damaging tropical cyclone that formed off the coast of the Cabo Verde Islands. On 12 UTC 14 September 2018, Florence made landfall as a weakened category 1 Hurricane in Wrightsville Beach, NC. In the midst of landfall, Florence’s ground speed stalled considerably to near zero. Because of this stall, Florence continued to accumulate feet of rain along the coastline, and the inundation of seawater became extreme. Due to the impacts of Florence, the Weather Research and Forecasting Model (WRF-ARW) was used to simulate the tropical cyclone and provide insight into the thermodynamics and dynamics that played a significant role at the time of landfall. After the control case, several sensitivity experiments were conducted. The historical sensitivity experiments utilize the thermodynamic and moisture fields of ERA5 reanalysis data from 1968 and 1998, respectively, to modify the thermodynamic and moisture fields in the initial conditions of the WRF–ARW control case. In addition, to study the potential future climate impacts of Florence, the NCAR CESM Global Bias-Corrected CMIP5 Output to Support WRF/MPAS Research dataset was utilized. The same approach was taken as the historical versions of Florence for sensitivity experiments for future climate, i.e., thermodynamic and moisture fields for both 2038 and 2068 under the RCP6.0 and RCP8.5 climate scenarios, respectively. Results suggest a corresponding intensity shift with minor track deflections. Based on these modifications, synoptic and mesoscale dynamics will be studied to provide insight into how Florence-like hurricanes may change based on certain climate scenarios. Full article

Ground source heat pump (GSHP) systems, while energy-efficient, often face persistent soil thermal imbalance in heating-dominated severe cold regions, which undermines their long-term performance and sustainability. This study proposes a TRNSYS-GenOpt framework for the life-cycle cost optimization of hybrid GSHP systems integrating electric boilers and geothermal regulation towers. A transient model for a 5650 m² fire station in Changchun was developed, employing the Hooke–Jeeves algorithm to co-optimize boiler capacity, borehole depth, and geothermal regulation tower airflow under constraints on heating supply temperature and soil thermal balance. Time-of-use electricity pricing was incorporated for realistic operational economics. The optimized configuration (148 m, 864.8 kW, 290,400 m³/h) achieved a minimum 20-year life-cycle cost of CNY 1.13 million. Sensitivity analysis revealed “rigid design, flexible cost” characteristics: optimal parameters remained invariant across discount rate variations (3.5–7.5%) and equipment costs (±20%), while life-cycle cost showed the highest sensitivity to electricity pricing and discount rates. The long-term simulation confirmed compliance with all physical constraints. This methodology demonstrates that thermodynamic constraints supersede economic trade-offs in severe cold climates, providing engineers with a reliable tool for sustainable hybrid geothermal system design. Full article

Graphite remains the predominant negative electrode material in commercial lithium-ion batteries (LIBs); however, its practical performance is increasingly limited by interface-driven degradation rather than bulk intercalation. This review examines the interconnected electrochemical, mechanical, and safety challenges associated with uncoated and coated graphite, with particular focus on how solid electrolyte interphase (SEI) formation and evolution deplete cyclable lithium, increase interfacial resistance, and induce polarization that leads to lithium plating and dendritic growth during rapid charging and low-temperature operation. Electrolyte and solvation engineering are highlighted as coating-free strategies to mitigate these issues by reducing Li⁺ desolvation barriers and directing interphase chemistry toward thinner, more ion-conductive, fluorinated SEI films that inhibit plating while maintaining high-rate capability. Coated graphite approaches are compared, including carbon, inorganic, and polymer coatings that function as artificial SEI layers to minimize direct electrolyte contact, stabilize interphase composition, and enhance mechanical durability. Key trade-offs are discussed, including decreased first-cycle coulombic efficiency (FCCE) due to increased surface area, transport limitations arising from excessively thick coatings, nonuniform coverage leading to local current hotspots, and side reactions induced by the coatings. The discussion is further extended to sodium and potassium systems, explaining how larger ion sizes, unfavorable thermodynamics, and significant lattice expansion hinder their insertion into graphite, and summarizing strategies such as interlayer expansion and alternative carbon architectures that improve reversibility for larger ions. This review concludes that achieving durable, safe, and fast-charging graphite electrodes requires an integrated interfacial design that combines optimized graphite morphology, electrode architecture, and electrolyte chemistry. Full article

A novel open-loop thermosyphon heat engine driven by low-temperature waste heat is proposed for simultaneous power generation and freshwater production. Large quantities of low-grade thermal energy from sources such as data centres remain underutilised due to the limited efficiency and mechanical complexity of conventional heat engines at low temperatures. The proposed system employs thermosyphon-driven circulation and gravity-assisted condensate return, eliminating mechanical pumping and reducing parasitic losses. A mathematical model was developed to evaluate system performance under low-grade heat input conditions. For a baseline case with 50% turbine isentropic efficiency and 5000 W thermal input, the model predicts an overall efficiency of 3.8% and freshwater production of 143 kg/day. A parametric study was conducted to identify the dominant performance parameters and assess sensitivity to operating conditions. While the predicted power output does not exceed that of optimised Organic Rankine Cycle systems, the proposed configuration offers reduced mechanical complexity and inherent freshwater production through phase change. Unlike membrane-based desalination systems, the open-loop design can accommodate high-salinity feeds, including concentrated brine streams, enabling high recovery operation. These characteristics suggest potential application in low-temperature waste heat recovery scenarios where simplified operation, high-salinity tolerance, and combined energy–water generation are desirable. Full article

In this study, we evaluated various density functional theory (DFT) methods to obtain thermodynamic parameters, such as enthalpy and Gibbs free energy, and compared them with experimental values obtained from conductometric analysis. As a model system, we chose the heptakis(2,6-di-O-methyl)-β-cyclodextrin (DIMEB) complex with the recently synthesized fluorinated compound, butane-1,4-diyl bis(2,2,2-trifluoroethane-1-sulfonate) (BFS). The analysis was carried out in the temperature range of 293.15–313.15 K. A conformational search was performed to identify the most stable complexes. The final stage of optimization was conducted at the ωB97X-D4/6-31G(d,p) level of theory in the presence of water, modeled using the conductor-like polarizable continuum model (CPCM). The thermodynamic analysis indicates that almost all theoretical methods overestimate the enthalpy and Gibbs free energy. This also applies to Minnesota functionals, which are commonly recommended for thermochemistry studies. The best agreement with experimental results was obtained for the composite methods r²SCAN-3c and PBEh-3c, with the coefficient of determination (R² = 0.9972) indicating excellent correlation between r²SCAN-3c and experiment. Full article

Air-to-air heat pumps are a key technology for improving energy efficiency and reducing carbon emissions in residential buildings, yet their optimal control remains challenging under real-world conditions. This study evaluates the performance of a hybrid physical–LSTM model for controlling an air-to-air heat pump in a residential building in Zadar, Croatia. The hybrid framework integrates a first-order energy balance model of the building envelope with LSTM-based temperature correction using adaptive weighting. The physical model was calibrated and validated against 52,128 real IoT measurements collected during the 2024/2025 heating season, achieving high accuracy (RMSE ≈ 0.076 °C). Rolling one-day and continuous multi-day closed-loop simulations (up to 15 days) show that the hybrid model yields slightly lower RMSE in long-term runs compared to the pure physical model. However, this apparent statistical improvement is accompanied by systematic underestimation of indoor temperature and significantly higher simulated energy consumption. The results indicate that the observed effect originates from an implicit virtual heat flux introduced by the LSTM correction, which affects thermodynamic consistency in closed-loop operation. The findings highlight that short-term error metrics such as RMSE alone are insufficient for evaluating hybrid models intended for model predictive control (MPC). The main contribution of this study is the explicit demonstration and quantification of an implicit virtual heat flux generated by the LSTM correction in closed-loop multi-day operation, which leads to misleading statistical improvements while causing significant thermodynamic inconsistency and energy overconsumption. In 15-day continuous simulations the hybrid model (ω = 0.05–0.10) caused an indoor temperature underestimation of 1.25–1.31 °C and increased simulated electricity consumption by more than 300% (316 kWh vs. 72 kWh) compared to the physical model. These results have direct implications for the development of reliable digital twins and model predictive control strategies in residential HVAC systems. Full article

Traditional analyses of transport phenomena rely on prescribed geometric boundaries, yet natural flow systems dynamically evolve their architecture to maximize access to currents. To address this disparity, we propose a field-theoretic framework for the constructal law that treats physical geometry as a dynamic state variable, represented by a time-dependent conductivity tensor. Using a variational approach grounded in non-equilibrium thermodynamics, we derive a general tensor evolution equation. Within this framework, macroscopic flow architecture emerges deterministically from the continuous competition between non-linear flux-induced accretion, linear entropic relaxation, and spatial smoothing. Scaling analysis reduces this dynamic to a tri-parameter dimensionless phase space: a morphogenic number driving structural growth, a structural diffusion number governing spatial coherence, and a stochastic intensity number providing the microscopic seeds for symmetry breaking. Our principal result is the analytical prediction of a critical bifurcation. When the local morphogenic number strictly exceeds unity, the system escapes its stable, isotropic configuration and branches into highly conductive, anisotropic architectures. We demonstrate the predictive validity and trans-scalar applicability of this continuum theory by mapping it to highly diverse phase transitions, successfully capturing phenomena ranging from microscopic aerosol agglomeration and microbial resistance, to macroscopic coral plasticity and crystal growth instabilities, and finally to the astrophysical launching of relativistic jets from black holes. Full article

Background/Objectives: Rebamipide is a gastroprotective agent with poor aqueous solubility and rapid gastrointestinal clearance, leading to reduced therapeutic efficiency. This study aimed to enhance the solubility, mucoadhesion, and sustained oral delivery of Rebamipide through the development of a deep eutectic mixture (DEM)-based bioadhesive controlled-release granule formulation. Methods: In silico hydrogen-bonding interactions between Rebamipide, malonic acid, and urea were analyzed using CCDC tools. A thermodynamically stable DEM (1:3:1) was prepared and incorporated into bioadhesive granules using chitosan and HPMC. Physicochemical characterization was conducted using FTIR, DSC, TGA, and PXRD. Solubility, in vitro dissolution, ex vivo mucoadhesion (sheep gastric mucosa), and in vivo gastric retention (BaSO₄-loaded granules in rats) were evaluated. Results: The optimized DEM significantly enhanced Rebamipide solubility (10.08 mg/mL vs. 0.045 mg/mL). Solid-state analyses confirmed hydrogen-bond formation and reduced crystallinity. DEM granules exhibited sustained drug release over 24 h (99.7 ± 0.8%) with improved dissolution efficiency compared to the marketed tablet (Mucosta®, 100 mg; T₅₀%: 5.03 h vs. 0.82 h). Kinetic modeling indicated non-Fickian anomalous transport (n = 0.47). The bioadhesive force of DEM granules (0.29 ± 0.02 N) was significantly higher than that of the pure drug and physical mixture. In vivo radiographic studies confirmed prolonged gastric retention. Conclusions: The DEM-based bioadhesive granule system effectively improves solubility, dissolution rate, mucoadhesion, and gastric retention of Rebamipide. This approach represents a promising platform for once-daily gastroretentive oral delivery, pending further pharmacokinetic evaluation. Full article

Molten salt chlorination is a key industrial route for producing titanium tetrachloride (TiCl₄), yet the atomistic catalytic role of iron (Fe) in the carbothermic chlorination of titanium oxides remains unclear. Here, the chlorination behavior of the NaCl–C–Cl₂–FeTiO₃ system was investigated by combining thermodynamic calculations with Ab Initio Molecular Dynamics (AIMD) and Deep Potential Molecular Dynamics (DPMD) simulations. AIMD results show that carbon adjacent to Fe exhibits enhanced reactivity, and that Fe-C synergistic electron transfer promotes both titanium oxide reduction and subsequent titanium chlorination. DPMD results further reveal that Fe not only accelerates these transformations, but also improves interfacial contact among carbon, titanium oxides, and molten salt, thereby enhancing mass transfer and shortening the formation time of TiCl₄. Temperature-dependent analysis indicates that Fe-C and C-O coordination numbers remain high near 1073 K, where TiCl₄ formation is efficient and relatively stable. Although increasing temperature can further enhance diffusion, its effect on reaction acceleration is limited, while excessively high temperatures weaken Fe-C interactions and reduce catalytic efficiency. These findings clarify the catalytic mechanism of Fe in molten salt chlorination at the atomic scale and provide theoretical support for process optimization. Full article

Accurate retrieval of visibility grades is critical for transportation safety. Due to the highly complex meteorological backgrounds, traditional global deep learning models frequently struggle with limited physical traceability and feature heterogeneity. To address these challenges by enhance physical traceability and reduces heterogeneity, this study proposes a scenario-adaptive visibility retrieval framework based on multi-source synergy, namely TabPFN-ExtraTrees (TabPFN-ET), targeting major transportation routes in Anhui Province, China. Fusing Fengyun-4 (FY-4A/4B) satellite multispectral observations with ground meteorological data, this framework utilizes the divide-and-conquer routing mechanism of ExtraTrees to decouple the complex, heterogeneous feature space into highly homogeneous sub-scenarios. Subsequently, the TabPFN model conducts high-precision inference within each specific subspace. Evaluations on a class-balanced benchmark demonstrate that TabPFN-ET achieves an Overall Accuracy of 0.681, outperforming baseline models such as SAINT across various metrics. Furthermore, this paper conducts a physically consistent analysis of the framework. Feature importance and node profiling corroborate its physical consistency: the FY-4 upper-level water vapor channel (Channel 09) and near-surface humidity act as the macroscopic atmospheric stability and microscopic thermodynamic constraints, respectively, driving the model’s scene decoupling and inference. Cross-regional tests in Jiangsu provide preliminary indications of context-specific transferability. Full article