Search Results (6,629)

Periodic charging–storage–discharging induces cyclic variations in temperature and pressure inside the rock cavern, forming a complex thermo-hydro-mechanical (THM) coupling problem that impacts the structural stability and energy storage efficiency of the cavern. In this study, a thermodynamic model of CAES rock caverns incorporating heat exchange and air leakage was established, enabling accurate characterization of temperature and pressure variations in the cavern during charging–storage–discharging. Based on this, the influences of heat transfer coefficient and charging temperature on the thermodynamic process were discussed. The primary reason for the pressure and heat losses during the high-pressure storage stage was analyzed. Finally, a long-term performance simulation of a CAES cavern over a 365-day operation period was conducted. Results indicated that: (1) Temperature, pressure, and air leakage rate all presented a trend of “up-down-down-up”, synchronized with the four operation stages of charging, high-pressure storage, discharging, and low-pressure storage; (2) during high-pressure storage, continuous heat exchange between compressed air and the cavern wall causes a reduction in pressure and temperature. The magnitude of this reduction decreases with increasing heat transfer coefficient but increases with rising charging temperature; (3) after 365 days of operation, the air leakage rate decreased from 10⁻² magnitude to 10⁻³, with increased pore pressure in the surrounding rock reducing the pressure gradient, thereby impeding air leakage from the cavern under the assumption of constant permeability. Full article

The Earth–Air Heat Exchanger (EAHE), also referred to as an air–soil heat exchanger, represents an effective passive cooling technology that exploits the thermal inertia of the ground. This study presents a combined experimental and analytical investigation of an EAHE system installed at the Faculty of Sciences of Agadir (Morocco). A steady-state analytical model based on convective heat transfer between the airflow within a buried duct and the surrounding soil is developed to describe the axial evolution of air temperature along the exchanger. The model is formulated under a sensible heat transfer framework, where the influence of humidity is accounted for through its effect on the thermophysical properties of moist air, while latent heat transfer and condensation phenomena are neglected. An instrumented experimental setup was implemented to perform continuous measurements of air temperature and relative humidity over a seven-month monitoring period. The experimental results indicate that the outlet air temperature remains stabilized within the range of 23.5–23.8 °C, despite significant variations in ambient temperature (13–38 °C). A parametric analysis is conducted to assess the influence of duct diameter, airflow velocity, and humidity through its effect on moist air properties on the thermal performance of the system. The close agreement between experimental observations and analytical predictions demonstrates the validity and predictive capability of the proposed model. These findings highlight the potential of EAHE systems as an effective passive cooling solution for greenhouse applications in semi-arid climatic conditions. Full article

Creeping bentgrass (Agrostis stolonifera), a widely used cool-season turfgrass, is highly susceptible to heat stress, which severely impairs its growth and physiological functions. In this study, two cultivars with contrasting heat tolerance, the heat-tolerant 13M and the heat-sensitive Seaside II (SII), were pretreated with diethyl aminoethyl hexanoate (DA-6) or distilled water and then exposed to either normal temperature or heat-stress conditions. Physiological traits and lipidomics were analyzed to investigate the regulatory role of DA-6 in lipid remodeling under high-temperature stress. Results showed that exogenous DA-6 application significantly mitigated physiological damage in both genotypes under heat stress. Under heat stress, compared with their corresponding untreated plants, DA-6 pretreatment increased the Fv/Fm by 15% in 13M and by 33% in SII; for the PI_ABS, DA-6 pretreatment increased it by 32% in 13M and by 55% in SII; for electrolyte leakage, DA-6 pretreatment reduced it by 24% in 13M and by 11% in SII. The analysis of lipidomics found that heat stress significantly reduced the accumulation of total lipids, phospholipids (PLs), glycolipids (GLs), and sphingolipids (SLs) in two genotypes, but under heat stress, 13M maintained significantly higher content of these lipids than SII. Exogenous DA-6 application significantly alleviated the heat-induced decline in photosynthesis-related glycolipids in SII. Specifically, MGDG, DGDG, and SQDG increased by 186%, 85%, and 32% in heat-stressed SII + DA-6, respectively, relative to heat-stressed SII without DA-6 pretreatment. In addition, DA-6 treatment also alleviated the heat-induced reduction in chloroplast- and mitochondria-associated lipids, including PG, LPG, and CL, in both genotypes. For heat-stressed 13M + DA-6, these lipids increased by 20%, 114%, and 22%, respectively, compared with heat-stressed 13M without DA-6 pretreatment; for heat-stressed SII + DA-6, they increased by 141%, 76%, and 184%, respectively, compared with heat-stressed SII without DA-6 pretreatment. These changes may contribute to improved stability of chloroplasts and mitochondria under heat stress. Furthermore, DA-6 application significantly promoted the accumulation of PC, PE, LPC, LPE, Cer, CerP, and Hex3Cer in both genotypes under heat stress. For 13M, the increases ranged from 18% to 120%; for SII, from 44% to 254%. In heat-stressed SII + DA-6 only, DA-6 also increased PA, PS, MLCL, DLCL, Hex1Cer, and Hex2Cer by 82%, 45%, 84%, 59%, 53%, and 41%, respectively, relative to heat-stressed SII without DA-6 pretreatment. These PLs and SLs are essential for maintaining plasma membrane integrity and mediating stress signal transduction. In addition, the application of DA-6 significantly reduced the heat-induced increase in unsaturation levels of total lipids in both genotypes, indicating that the DA-6 improved lipid saturation levels to better adapt to heat stress. Current findings demonstrated that the DA-6 application improved heat tolerance of creeping bentgrass associated with its regulation of lipid remodeling. Future investigations incorporating multi-omics approaches could comprehensively dissect the DA-6-induced signaling pathways and regulatory networks underlying heat-stress response in cool-season grass species. Full article

Mobile thermal energy storage (M-TES) demonstrates significant commercialization potential in industrial waste heat recovery, distributed heating, and clean heating applications, which is primarily based on three technical pathways: sensible heat storage, latent heat storage using phase change materials (PCMs), and thermochemical heat storage. The updated status of M-TES, mainly on PCMs and thermochemical ones, and the challenges facing application were reviewed, and potential development trends were discussed in the present study. Sensible heat storage is relatively mature and cost-effective; however, it suffers from low energy density and comparatively high heat loss during storage and transport. Latent heat storage utilizes the phase transition enthalpy of PCMs to store thermal energy, offering higher energy density and near-isothermal heat release, making it a focal point of current academic and industrial research. Nevertheless, latent heat storage still faces technical bottlenecks, including low thermal conductivity, phase separation, and supercooling of PCMs. Thermochemical heat storage relies on reversible chemical reactions to convert and store thermal energy as chemical energy, theoretically achieving the highest energy density and minimal heat loss. However, due to its technical complexity and high system cost, thermochemical storage remains largely in the early stages of research and demonstration. Overall, as a bridge between heat supply and demand, the development trend emphasizes the design of high-performance composite PCMs, enhanced system integration, and intelligent operational management. However, its large-scale deployment is still constrained by challenges related to energy density, heat transfer enhancement, long-term material stability, and techno-economic feasibility. Full article

The global energy transition to sustainable renewable energy sources has caused a growing demand for advanced energy storage systems, particularly sensible thermal energy storage systems because of their low cost and high performance. This work experimentally investigates the potential use of South African ferroalloy slags as filler materials in packed bed configurations. Ferrochrome and silicomanganese slags are characterised and used as filler materials, and air is used as the heat transfer fluid. The experiments are designed for high-temperature systems, with working temperatures of up to 600 °C and usable energy limited to 400 °C. The slags’ thermophysical properties are evaluated and used to assess their performance during thermal cycling. Material phase composition, grain size, and porosity distributions are analysed with automatic scanning electron microscopy. Thermogravimetric analysis is done to study the chemical stability of the slags at temperatures reaching up to 1000 °C. The slags’ thermophysical properties and thermal energy storage capacities are comparable to other candidate filler materials for high thermal energy storage systems. High thermal energy storage efficiencies of 70–90% are achieved in the experiments. However, a high pressure drop of up to 2 bar is recorded. The slags are found to be chemically stable for use in systems with working temperatures of up to 1000 °C. Volumetric energy densities of 165–187 kWh/m³ are recorded during thermal energy recoveries at temperatures above 400 °C. The slags were found to be suitable for use as filler materials in sensible energy storage systems with working temperatures of up to 1000 °C. Full article

Transformer fires within indoor substations constitute severe hydrocarbon fire scenarios characterized by rapid heat release rates and extreme peak temperatures, posing a critical threat to the structural integrity of steel frameworks and power grid stability. To rigorously assess structural safety under such conditions, this study employs a sequential thermal-mechanical coupled numerical methodology combining Computational Fluid Dynamics (CFD) and Finite Element Analysis (FEA). Focusing on a 110 kV indoor substation, the research simulates the transient, non-uniform temperature fields induced by transformer oil combustion and analyzes the thermo-mechanical response of key steel components. Furthermore, the protective efficacy of two non-intumescent coatings (Material A and Material B) with distinct thermal conductivities is systematically evaluated. Computational results elucidate significant thermal stratification, with upper-level structures sustaining exposure to temperatures exceeding 1500 K. Unprotected steel components subjected to direct flame impingement exhibit severe stress concentrations and plastic deformation, reaching their load-bearing limit within 4825 s. The application of fire-retardant coatings markedly enhances fire resistance; a 5 mm layer of Material A (λ = 0.20 W/(m·K)) extends the time to failure to approximately 9390 s. Notably, increasing the thickness of Material A to 20 mm, or alternatively employing a 10 mm layer of Material B (λ = 0.10 W/(m·K)), effectively mitigates thermal stress concentrations. This ensures structural deformation remains within safe limits throughout a 3 h (10,800 s) fire duration. This study provides a theoretical basis and quantitative engineering references for the optimal fire protection design of substation steel structures. Full article

The Mediterranean Basin faces increasing risks from extreme weather events, particularly heat stress, which severely threatens the productivity of sensitive crops, like processing tomato (Solanum lycopersicum L.). This study evaluated the agronomic, physiological, quality, and economic performance of using Mater-Bi^®-based biodegradable mulch films—varying in color (black and White/Black) and thickness (12 µm and 15 µm)—in two distinct Southern Italian pedoclimatic sites: Sicily and Campania. The aim was to define site-specific optimization strategies by comparing three biodegradable mulch film treatments, 12 µm (BDM12), 15 µm (BDM15), and Black/White (BDBW), against bare soil (BS). The results confirmed that biodegradable mulching enhances plant physiological status, such as chlorophyll and nitrogen balance index (NBI), and marketable yield compared to BS. The effectiveness of the films depended significantly on the environment. In Sicily, the BDBW (White/Black) film provided the maximum marketable yield (804.7 q ha⁻¹), confirming its crucial role in mitigating high soil temperatures through radiation reflection. Conversely, in the more favorable Campanian environment, the thicker black film (BDN15) achieved the highest yield (867.3 q ha⁻¹), indicating that microclimate stability is prioritized over heat mitigation under optimal conditions. Quality analysis showed high variability; while the Sicilian site generally favored color and antioxidant capacity, total soluble solids (°Brix) exhibited a trade-off. BDBW achieved the highest °Brix (6.1) in Sicily, while BS yielded the highest (6.03) in Campania, suggesting that slight water stress can concentrate sugars at the expense of total yield. The economic analysis demonstrated that the °Brix increase achieved with biodegradable films provided a net additional economic return superior to BS in both sites (up to +52.92% with BDBW). These findings suggest that the adoption of biodegradable mulching represents a key strategy for the sustainable intensification of processing tomato. Future cultivation strategies must mandatorily integrate the personalized selection of film color and thickness as a key element to synergistically maximize yield, quality, and economic return, tailored to the specific pedoclimatic conditions of each production site. Full article

Environmental fires pose a serious threat to energy security, ecosystems and public safety, whilst traditional halogenated flame retardants suffer from limitations such as high environmental residue risks and insufficient flame-retardant efficacy. In this study, sodium alginate (SA) was utilised as the matrix, with the incorporation of ammonium polyphosphate (APP) and phytic acid (PA), in conjunction with SiO₂-APTES surface modification, to prepare nitrogen–phosphorus synergistic bio-based flame-retardant gels. The present study systematically investigated the influence of the N/P molar ratio on the gelation kinetics, rheological behaviour, microstructure and flame-retardant performance of the gel. The study revealed a nitrogen–phosphorus coupled gas–solid two-phase synergistic flame-retardant mechanism. The results indicate that at an N/P ratio of 1/4, the gel forms a stable dual-network structure comprising ionic cross-links and Si–O–P covalent bonds. In the gas phase, the thermal decomposition of APP releases inert NH₃, which dilutes oxygen and quenches gas-phase radicals (·OH, ·H). In the condensed phase, the phosphate groups of PA-catalysed SA form Si–O–P covalent bonds with SiO₂ under the mediation of APTES, creating a dense, insulating char layer. In comparison with the control group (N/P = 0/0), the optimal gel sample (N/P = 1/4) demonstrated a 33% increase in shear stress, a 10% reduction in the peak heat release rate (HRR), a 75% decrease in total smoke production (TSP), and a 150% increase in char layer thickness after combustion, while maintaining adequate mechanical strength, thermal stability, and environmental friendliness. This work provides novel insights and strategies for the development of green, highly efficient flame-retardant materials for environmental fire prevention and control. Full article

The characteristics of two-phase flow in heterogeneous shale porous structures are of critical importance for oil and gas extraction and for evaluating the efficiency of underground resource recovery and carbon sequestration. However, although non-isothermal two-phase flow has been investigated in previous studies, systematic research on non-isothermal CO₂–crude oil displacement in heterogeneous shale porous structures remains relatively scarce. In this study, a multi-phase simulator was employed to simulate non-isothermal CO₂–crude oil displacement in heterogeneous porous structures, and the effects of injection rate, injection temperature, and wettability on two-phase flow characteristics in heterogeneous porous media were systematically analyzed. The results indicate that changes in the viscosity ratio between the displacing and displaced phases—induced by heat transfer—may be a key factor governing immiscible two-phase interfacial dynamics and flow behavior in heterogeneous porous structures. Injection temperature exerts a significant influence on both the main flow channels and local flow pathways within the porous structure; increasing the injection temperature of the displacing phase can effectively enhance displacement efficiency, with the steady-state CO₂ saturation increasing from 43.15% to 50.62% as the injection temperature increased from 293.15 K to 363.15 K. In addition, increasing the injection rate improves CO₂ sweep efficiency, with the steady-state CO₂ saturation increasing from 45.35% to 55.98% as the injection rate increased from 50 to 250 μm/s; however, excessively high injection rates lead to non-piston-like displacement and premature fluid breakthrough, and the CO₂ saturation decreased to 49.81% at 350 μm/s. Under strongly water-wet conditions, the CO₂ saturation after displacement stabilization is higher. Full article

The development of protective coatings that integrate self-healing and environmental tolerance is vital for extending substrate lifespan. In this study, a multifunctional hydrogel composite coating is developed based on a waterborne polyacrylate dynamic covalent network containing oxime–carbamate bonds. The functional monomer MEOC, which contains an oxime–carbamate dynamic bond, was synthesized and incorporated into the waterborne polyacrylate matrix to form a hydrogel network (OC-PA) with intrinsic self-healing capability. Prussian blue (PB) and nano-SiO₂ were incorporated to form a photothermal functional layer, imparting hydrophobicity and converting light into heat for de-icing, while also activating dynamic bond rearrangement within the substrate. When the MEOC content was 7 wt% and the PB content was 2 wt%, the coating temperature rose to 110 °C within 2 min under 0.6 W/cm² irradiation, and the scratch healed within 5 min. After 1 h of fracture repair, the tensile strength reached 6.68 MPa, with a repair rate as high as 92.91%, and de-icing time was reduced from 343 s to 183 s. The coating achieved a water contact angle >100°. At −20 °C, the icing delay time increased by 215%. The hydrogel coating also exhibited excellent abrasion resistance, chemical stability, UV aging resistance, and anti-fouling properties, offering a durable solution for demanding environments. Full article

Driven by the growing energy demand and severe challenges posed by climate change, reducing the high energy consumption of district heating systems while enhancing their flexibility and operational reliability has become an urgent priority. This study focuses on the heating system of a residential community in Zhengzhou, China, by developing a joint source-network-load simulation model and proposing a model predictive control (MPC) strategy tailored to the dynamic characteristics of the system. A white-box model of the building complex and heating system was established by coupling EnergyPlus and Modelica. Subsequently, the model was automatically calibrated using actual operational data and the GenOpt optimization tool, which further improved the simulation accuracy and optimal control performance of the model. The results show that the root mean square errors (RMSEs) of the calibrated secondary network supply water temperature, return water temperature, and indoor temperature decreased by 34.6% and 15.7%, respectively, verifying the effectiveness of the proposed calibration method. Furthermore, the proposed MPC strategy demonstrates significant advantages over conventional control baselines, greatly improving the temperature regulation accuracy and system stability. Compared to the baseline operation without MPC, the proposed strategy increases the user-side thermal comfort index from 56% to 100%, thereby significantly enhancing overall heating quality. Full article

Fixed external louvers are widely used to improve the environmental performance of glass curtain wall office buildings, yet existing studies more often report preferred solutions than transferable decision ranges for early-stage design. This study develops interval-based design rules for a standard-floor prototype of a point-supported glass curtain wall office building in Tianjin, a representative cold-climate city in China. A seven-variable design space integrating spatial-scale and shading variables was evaluated for 3000 Latin hypercube samples in a Rhino–Grasshopper–Honeybee workflow linked to Radiance and EnergyPlus, using Tianjin’s typical meteorological year data and GB 55015—2021-based office schedules, including an occupant density of 10 m²/person and occupied heating/cooling setpoints of 20/26 °C. Raw-sample statistics, Bootstrap-based stability testing, and surrogate-model-assisted continuous-response analysis were used to identify dominant variables, single-objective preferred intervals, and a neutral equal-weight baseline compromise zone. Under a neutral equal-weight baseline adopted for early-stage comparison, the compromise interval is concentrated around 20–25°, with 15–30° as a practical starting range, while alternative weighting scenarios show directional shifts toward the prioritized objective. Full article

This study describes the development of an electrochemical sensor for quantitatively measuring acetaminophen (ACOP) in drug tablets. The sensor design is based on the modification of glassy carbon electrode (GCE) using zinc oxide nanoparticles (ZnONPs) embedded in a naturally occurring clay matrix (Sa) functionalized with phenylalanine (Phe). To ensure that the ZnONPs are homogeneously dispersed on the clay surface, the nanocomposite was synthesized using an impregnation approach and low-temperature heat treatment. The amino acid promotes specific interactions with ACOP through hydrogen bonding and π-π stacking, acting as both a stabilizing agent and a molecular recognition moiety. FTIR, UV-Vis, XRD, and FESEM/EDX mapping were employed to fully characterize the developed material (ZnONPs-Sa/Phe). Cyclic voltammetry (CV) and differential pulse voltammetry (DPV) were used for the electrochemical determination of ACOP using the modified electrode GCE/ZnONPs-Sa/Phe. Parameters susceptible to affecting the sensitivity of the developed sensor were optimized, revealing that 5 µL of the suspension ZnONPs-Sa/Phe immobilized on GCE was ideal for the sensing of ACOP in a phosphate buffer solution at pH 2.0. The calibration curve obtained by plotting peak current intensity against ACOP concentration exhibited linear behavior within the concentration range between 0.02 µM and 0.28 µM, enabling determination of the limits of detection (LOD) and quantitation (LOQ) at 8.54 × 10⁻⁹ M and 2.84 × 10⁻⁸ M, respectively. The reproducibility, stability, and selectivity of the sensor were evaluated, followed by its application to the nano-sensing of ACOP in Africure and Doliprane tablets, yielding satisfactory results. The simplicity, affordability, and high analytical sensitivity of the developed sensor make this sensing platform a promising tool for pharmaceutical quality control applications. Full article

This study investigates unsteady magnetohydrodynamic free convection flow past a rotating vertical plate embedded in a Darcy–Forchheimer porous medium. The formulation incorporates Hall current, thermal radiation, viscous dissipation, Joule heating, and an Arrhenius-type chemical reaction with activation energy to represent thermo-reactive transport in an electrically conducting fluid. The coupled nonlinear equations governing momentum, thermal energy, and species concentration are transformed into dimensionless form and solved numerically using the Crank–Nicolson scheme. Grid independence and validation tests confirm the accuracy and stability of the numerical procedure. The results show that electromagnetic forces, rotation, porous resistance, and thermo-reactive effects significantly influence wall shear stress, heat transfer, and mass transport. In particular, the interaction between magnetic field strength and Hall current alters near-wall transport behavior, highlighting the role of electromagnetic coupling in rotating porous systems. The study provides physical insight relevant to the design and analysis of transport processes in high-temperature energy systems, rotating reactors, and porous thermal management devices. Full article

Developing specialized aluminum alloys for additive processes is a strategic approach to achieve both strength and mass reduction in high-performance products. The prospects of the new metallic powder composition of Al3Ca2La2Mn0.4Zr alloy for laser powder bed fusion (LPBF) have been studied. It has been found that the best printing mode, providing a more than 99.0% density of the specimens, includes substrate heating to 150 °C and printing with a 350 W laser power, a 1500 mm/s printing speed, a 0.08 mm hatch distance and a 0.03 mm layer thickness (energy density 97.2 J/mm²). The optimal printing mode provides for the following strength parameters: UTS 366 ± 5 MPa, yield strength 223 ± 8 MPa, and relative elongation 30 ± 3%. The alloy exhibits high thermal stability for the structure and its properties. Annealing temperatures below 300 °C have no critical effect on the alloy hardness: the hardness decreases by less than 10% of the initial 110 ± 3 HV. At 350 °C, the hardness decreases by 25.5% (82 ± 2 HV); 100 h exposure at 350 °C reduces the UTS to 265 ± 2 MPa and the yield strength to 178 ± 10 MPa, while maintaining the relative elongation of 29 ± 2%. Full article