Search Results (3,559)

Heat exchangers are central to energy and process industries, yet performance is bounded by the trade-off between higher heat transfer and greater pressure drop. This review targets indirect-type heat exchangers and organizes bioinspired strategies through a multi-scale lens of surface, texture, and network scales. It provides a structured comparison of their thermo-hydraulic behaviors and evaluation methods. At the surface scale, control of wettability and liquid-infused interfaces suppresses icing and fouling and stabilizes condensation. At the texture scale, microstructures inspired by shark skin and fish scales regulate near-wall vortices to balance drag reduction with heat-transfer enhancement. At the network scale, branched and bicontinuous pathways inspired by leaf veins, lung architectures, and triply periodic minimal surfaces promote uniform distribution and mixing, improving overall performance. The survey highlights practical needs for manufacturing readiness, durability, scale-up, and validation across operating ranges. By emphasizing analysis across scales rather than reliance on a single metric, the review distills design principles and selection guidelines for next-generation bioinspired heat exchangers. Full article

Air conditioners are a critical adaptation measure against heat- and cold-related risks under climate change. However, their electricity use and refrigerant leakage increase greenhouse gas (GHG) emissions. This study developed a data-driven life-cycle assessment (LCA) framework for residential room air conditioners in Japan by integrating large-scale field operation data with life-cycle climate performance (LCCP) modeling. We aggregated 1 min records for approximately 4100 wall-mounted split units and evaluated the 10-year LCCP across nine climate regions. Using the annual operating hours and electricity consumption, we classified the units into four behavioral quadrants and quantified the life-cycle GHG emissions and parameter sensitivities for each. The results show that the use-phase electricity dominated the total emissions, and that even under the same climate and capacity class, the 10-year per-unit emissions differed by roughly a factor of two between the high- and low-load quadrants. The sensitivity analysis identified the heating hours and the setpoint–indoor temperature difference as the most influential drivers, whereas the grid CO₂ intensity, equipment lifetime, and refrigerant assumptions were of secondary importance. By replacing a single assumed use scenario with empirical profiles and behavior-based clusters, the proposed framework improves the representativeness of the LCA for air conditioners. This enabled the design of cluster-specific mitigation strategies. Full article

In regions with hot summers and cold winters, elderly care buildings face the dual challenges of high energy consumption and stringent thermal comfort requirements. Using Nanchang as a case study, this research presents an optimization approach that integrates phase change material (PCM) walls with the window-to-wall ratio (WWR). PCM wall performance was tested experimentally, and EnergyPlus simulations were conducted to assess building energy use for WWR values ranging from 0.25 to 0.50, with and without PCM. The phase change material (PCM) used in this study is paraffin (an organic phase change material), which has a melting point of 26 °C and can store and release heat during temperature fluctuations. The experimental results show that PCM walls effectively reduce heat transfer, lowering the surface temperatures of external, central, and internal walls by 3.9 °C, 3.8 °C, and 3.7 °C, respectively, compared to walls without PCM. The simulation results predict that the PCM wall can reduce air conditioning energy consumption by 8.2% in summer and total annual energy consumption by 14.2%. The impact of WWR is orientation-dependent: east and west façades experience significant cooling penalties as WWR increases and should be maintained at or below 0.30; the south façade achieves optimal performance at a WWR of 0.40, with the lowest total energy load (111.2 kW·h·m-2); and the north façade performs best at the lower bound (WWR = 0.25). Under the combined strategy (south wall with PCM and WWR = 0.40), annual total energy consumption is reduced by 9.8% compared to the baseline (no PCM), with indoor temperatures maintained between 18 and 26 °C. This range is selected based on international thermal comfort standards (e.g., ASHRAE) and comfort research specifically targeting the elderly population, ensuring comfort for elderly occupants. These findings offer valuable guidance for energy-efficient design in similar climates and demonstrate that the synergy between PCM and WWR can reduce energy consumption while maintaining thermal comfort. Full article

The relevance of this study is driven by the increasing requirements for the energy efficiency and indoor comfort of residential and public buildings, particularly in regions with extreme climatic conditions characterized by substantial daily and seasonal temperature fluctuations. Effective management of heat transfer through building envelopes has become a key factor in reducing energy consumption and improving indoor comfort. This paper presents the results of an experimental–numerical investigation of the thermal behavior of an adaptive exterior wall system with a controllable air cavity. Steady-state and transient simulations were performed for three envelope configurations: a baseline design, a design with vertical air channels, and an adaptive configuration equipped with adjustable openings. Quantitative analysis showed that during the winter period, the adaptive configuration increases the interior surface temperature by 1.5–2.3 °C compared to the baseline design, resulting in a 12–18% reduction in the specific heat flux through the wall. In the summer period, the temperature of the exterior cladding decreases by 3–5 °C relative to the baseline, which reduces heat gains by 8–14% and lowers the cooling load. Additional analysis of temperature fields demonstrated that the presence of vertical air channels has a limited effect during winter: temperature differences at the surfaces do not exceed 1 °C. A similar pattern is observed in warm periods; however, due to controlled air circulation, the adaptive configuration provides an improved thermal regime. The results confirm the effectiveness of the adaptive wall system under the climatic conditions of southern Kazakhstan, characterized by high solar radiation and large diurnal temperature variations. The practical significance of the study lies in the potential application of adaptive façades to enhance the energy efficiency of buildings during both winter and summer seasons. Full article

Lithium-ion batteries (LIBs) are currently widely used in the electric vehicle sector and have become one of the core components of new energy vehicles. To ensure that the maximum temperature (T_max) and maximum temperature difference (∆T_max) remain within acceptable limits after high-rate discharge, this study proposes a novel air-cooled battery thermal management system (BTMS). This BTMS features innovative design elements in its novel battery case walls and contour-following fin structure. Through physical testing of 21,700 LIB discharges and comparative numerical simulations, the accuracy of the simulation model is ensured. Orthogonal experimental analysis is conducted at four distinct levels for each of the four structural factors involved. The final results demonstrate that the novel battery pack wall and contour-shaped fin structure proposed in this paper significantly enhance the heat dissipation capability of air-cooled BTMS. The proposed Model 9 configuration exhibits optimal thermal performance metrics. The T_max after 3C rate discharge reaches 39.4 °C, with a ∆T_max of 7.4 °C. This study demonstrates significant application potential in the structural implementation of air-cooled BTMSs. Full article

Three different Gas Tungsten Arc Welding methods—DC single electrode, DC double electrode, and PC double electrode—were analyzed using SS304 steel as the base material. Numerical models were developed to simulate the arc plasmas and calculate heat flux, current density, and wall shear stress on the surface of the workpiece. These data were used as input to simulate the weld pools across all three configurations. Experimental validation showed a good agreement with the numerical results. In the double-electrode setup, electromagnetic interaction caused the arcs to deflect, resulting in an 8% reduction in the maximum heat flux and a 4% decrease in the maximum current density. Marangoni stress had a notable effect on the weld pool shape, creating a -shaped pool with the stationary single-electrode setup, whereas the double-electrode setup produced a -shaped pool after 2 s. In the moving weld pool configurations, the sizes of the pools were maximum at the trailing electrodes. The pool was 1.7 mm deep and 5.6 mm wide in DC double- and 1.4 mm deep and 5.4 mm wide in PC double-electrode configurations. The pool depth and width were only 1.0 mm and 4.2 mm when a DC single-electrode setup was used. Comparing the three methods, the DC double-electrode setup produced the largest pool size. The findings of this research offer guidance for enhancing different arc settings and electrode arrangements to attain the intended welding quality and performance. Full article

Sealing tunnel portals is widely recognized as a pivotal strategy for mitigating fire hazards in tunnel safety management. Nevertheless, the interplay between fire source locations—both longitudinally and transversely—and its impact on flame behavior and ceiling temperature profiles within enclosed structures has not been fully elucidated. Utilizing a 1:15 reduced-scale rectangular tunnel model, this research investigates how varying the fire source position affects the maximum ceiling temperature under enclosed scenarios. Dimensionless parameters, including the longitudinal dimensionless distance D and transverse dimensionless distance Z′, were derived through dimensional analysis. Observations indicate that as the fire approaches the enclosed end, the flame initially leans toward the boundary, peaking in inclination at D = 0.73, and subsequently exhibits a “wall-attached combustion” pattern due to wall confinement. While lateral displacement of the fire source pushes the high-temperature zone toward the corresponding side wall, the longitudinal temperature rise follows a non-monotonic pattern: declining continuously in in Region I (0 ≤ D ≤ 0.73) and rebounding in Region II (0.73 < D < 1). Based on these findings, a dimensionless prediction model incorporating heat release rate (HRR), transverse offset, and longitudinal fire location was developed. Furthermore, a thermal accumulation factor was introduced to refine the predictive model in Region II. The results offer theoretical insights to support fire protection design and risk assessment in enclosed tunnels. Full article

Due to its high energy density, liquid Hydrogen is an essential fuel for both terrestrial energy systems and space propulsion. However, uncontrolled evaporation poses a challenge for cryogenic storage and transport technologies. Accurate modeling of evaporation remains difficult due to the multiscale menisci formed by the wetting liquid phase. Thin liquid films form near the walls of containers, ranging from millimeters to nanometers in thickness. Heat conduction through the solid walls enables high evaporation rates in this region. Discrepancies in the reported values of the accommodation coefficients (necessary inputs to models) further complicate evaporation calculations. In this study, we present a novel multiscale model for CFD simulations of evaporating Hydrogen menisci. Film profiles below 10 $\mu$m are computed by a subgrid model using a lubrication-type thin film equation. The microscale model is combined with a macroscale model above 10 $\mu$m. Evaporation rates are computed using a kinetic phase change model combined with in situ calculations of the accommodation coefficient using transition state theory. The submodels are implemented in Ansys Fluent^TM using User-Defined Functions (UDFs), and a method to establish two-way coupling is detailed. The modeling results are in good agreement with cryo-neutron experiments and show improvement over prior models. The model, including UDFs, is made available through a public repository. Full article

Heat threatens male fertility in crops, yet the regulatory basis of anther dehiscence under high temperatures remains unclear. We compared a heat-sensitive pepper cultivar (DL) with a heat-tolerant landrace (B021) across two anther stages using integrated transcriptome, small-RNA, degradome, co-expression, and enzymatic assays. DL showed a collapse of anther dehiscence above 34–38 °C, whereas B021 retained normal dehiscence at 39 °C, and histology revealed tapetal enlargement, premature degeneration, and locule contraction only in DL. RNA-seq indicated genotype- and stage-dependent reprogramming, with DL suppressing phenylpropanoid/cell-wall, transport, and proteostasis pathways, while B021 maintained reproductive and stress-integration programs. Small-RNA profiling and degradome sequencing identified conserved miRNA families with in vivo target cleavage, and notably, miR397 targeting a laccase gene showed stronger evidence in B021, which is consistent with controlled lignification. Functional organization of differentially expressed miRNA targets highlighted modules in respiration/redox, hormone and terpenoid metabolism, vascular–cell-wall programs, and proteostasis/osmotic buffering. WGCNA modules correlated with heat-tolerance traits converged on the same processes. Enzyme assays corroborated multi-omics predictions, with SOD, CAT, and POD activities consistently induced in B021 and limited MDA accumulation. Together, the data supports a model in which tolerant anthers sustain dehiscence under heat by coordinating secondary-wall formation, auxin/jasmonate/gibberellin crosstalk, respiratory and reactive oxygen species buffering, and protein/membrane quality control, providing tractable targets for breeding heat-resilient peppers. Full article

To address the issues of cities being overwhelmed by the waste and energy crisis, the pyrolysis of municipal solid waste (MSW), oil shale (OS) and their blends was investigated using a thermogravimetric simultaneous thermal analyzer in this study. The experimental research was conducted to investigate the thermal behavior and kinetic parameters of the different blending ratios of MSW and OS, to better utilize these intractable resources, observing whether there is a synergistic effect and trying to find the optimal process conditions. The Ozawa–Flynn–Wall method and the Kissinger–Akahira–Sunose method were used to calculate the activation energy at four different heating rates. The existence of interactions between MSW and OS was confirmed by comparing the experimental thermogravimetric and derivative thermogravimetric curves with the calculated ones. The findings of the thermogravimetric analysis, the calculation of theoretical and experimental curves, and kinetic analysis confirmed the interaction between the components and that the optimal blending ratio is 30% MSW and 70% OS. The optimality results in a relatively smaller activation energy (Eave = 115 kJ/mol), better comprehensive pyrolysis characteristics, and a more beneficial mutual effect. Full article

Considering the challenges associated with implementing emerging technologies and bacterial-derived antimicrobial metabolites at an industrial scale in the meat industry, this comprehensive review investigates the interactions between lactic acid bacteria-producing antimicrobial metabolites and emerging food preservation technologies applied to meat systems. By integrating evidence from microbiology, food engineering, and molecular physiology, the review characterizes how metabolites-derived compounds exert inhibitory activity through pH modulation, membrane permeabilization, disruption of proton motive force, and interference with cell wall biosynthesis. These biochemical actions are evaluated in parallel with the mechanistic effects of high-pressure processing, pulsed electric fields, cold plasma, irradiation, pulsed light, ultrasound, ohmic heating and nanotechnology. Across the literature, consistent patterns of synergy emerge: many emerging technologies induce structural and metabolic vulnerabilities in microbial cells, thereby amplifying the efficacy of antimicrobial metabolites while enabling reductions in process intensity. The review consolidates these findings to elucidate multi-hurdle strategies capable of improving microbial safety, extending shelf life, and preserving the physicochemical integrity of meat products. Remaining challenges include optimizing combinational parameters, ensuring metabolite stability within complex matrices, and aligning integrated preservation strategies with regulatory and industrial constraints. Full article

In recent years, the response mechanism of Pleurotus ostreatus to abiotic stress has received widespread attention. MnSOD is an important antioxidant enzyme that has been widely studied in animals and plants because of its functions. However, there is little research on the function and regulatory mechanism of MnSOD in the growth and development of edible fungi. This study investigated the role of Mnsod3 in the growth and development of P. ostreatus. The results showed that during the nutritional growth stage, heat stress can cause the cell wall of mycelia to shrink and the cells to exhibit cytoplasmic wall separation. RNA-seq revealed that Mnsod3 interference is strongly correlated with increased transcript levels of cell wall synthase genes and with increased tolerance to cell wall disruptors. During the primordium formation stage, the mycelial cell wall also significantly wrinkled under cold and light stresses. RNAi of Mnsod3 alleviated the cell wall wrinkling caused by cold and light stress, restored the smoothness of the cell walls, and increased mycelial tolerance to abiotic stress. This may be related to the slower formation rate of primordia, but the specific molecular mechanism still needs further research. and slowed the rate of primordium formation. In summary, Mnsod3 plays an important role in the growth and development of P. ostreatus under abiotic stress and plays a critical regulatory role in cell wall remodeling under abiotic stress. Full article

Conjugate heat transfer in non-Newtonian fluids is a fundamental phenomenon in thermal management systems. This study investigates the combined effects of magnetic field topology, heat absorption/generation, the thermal conductivity ratio, enclosure inclination, and power-law rheology using the lattice Boltzmann method. The parametric analysis shows that increasing the heat generation coefficient from −5 to +5 reduces the average Nusselt number by up to 97% for the pseudo-plastic fluids and up to 29% for the Newtonian fluids, while entropy generation increases by 44–86% depending on the thermal conductivity ratio. Increasing the inclination angle from 0° to 90° weakens convection and reduces heat transfer by nearly 77%. Magnetic field strengthening (Ha = 0–45) decreases the Nusselt number by 20–55% depending on the barrier temperature. Among all tested conditions, the highest thermal performance (maximum heat transfer and minimum entropy generation) occurs when using a pseudo-plastic fluid (n = 0.75), exhibiting high wall conductivity (TCR = 50) and heat absorption (HAPC = −5), a cold obstacle (${\mathsf{\theta }}_{\mathrm{b}}=0$), and zero inclination (λ = 0°), as well as in the absence of the magnetic field effects. These quantitative insights highlight the controllability of the conjugate heat transfer and irreversibility in the power-law fluids under coupled magnetothermal conditions. Full article

This study evaluates the effect of mould material and mould wall thickness on the thermal behaviour and cycle time of the LLDPE rotational moulding process by using RotoSim-based numerical simulation. This study was performed using three different metallic materials (low-carbon steel, brass, and aluminium), mould wall thicknesses of 3, 5, and 8 mm, and oven temperatures of 230, 250, and 270 °C. The simulations demonstrate that both mould material and wall thickness significantly influence the temperature evolution in the mould cavity and the overall cycle duration. Aluminium moulds provided the mould-cavity temperature closest to the oven conditions, the longest time with the polymer in the plastic/molten state, and the shortest total cycle time compared with steel and brass moulds. Increasing the mould wall thickness prolonged the cycle time for all materials, with the extension occurring primarily during the cooling stage. For a 3 mm wall thickness at 230 °C, the shortest cycle time was 2900 s (Al/3/230) and the longest was 3300 s (S/3/230). For an 8 mm wall thickness at 270 °C, the shortest cycle time was 4400 s (Al/8/270) and the longest was 4900 s (S/8/270). These results indicate that selecting an appropriate mould material and wall thickness can be an effective approach to shortening the cycle time and improving the efficiency of LLDPE rotational moulding. Full article

Methanol is a liquid fuel with high oxygen content and the potential for a closed-loop carbon-neutral production cycle. To investigate the mixture formation and combustion characteristics of a heavy-duty Port Fuel Injection (PFI) methanol engine, a three-dimensional numerical simulation model was established using the CONVERGE 3.0 software. Multi-cycle simulations were performed to analyze the influence of wall film dynamics on engine performance. The results indicate that the “adhesion–evaporation” equilibrium of the intake port wall film determines the in-cylinder mixture concentration. Due to the high latent heat of vaporization of methanol, severe wall-wetting occurs during the initial cycles, causing the actual fuel intake to lag behind the injection and leading to an overly lean mixture and misfire. Regarding injection strategies, the open valve injection (OVI) strategy utilizes high-speed intake airflow to reduce wall adhesion and improve fuel transport efficiency compared to closed valve injection. OVI refers to the fuel injection strategy that injects fuel into the intake port during the intake valve opening phase. The open valve injection strategy (e.g., SOI −500° CA) demonstrates distinct superiority over closed valve strategies (SOI −200°/−100° CA), achieving a 75% reduction in wall film mass. The long injection duration and early phasing allow the high-speed intake airflow to carry fuel directly into the cylinder, significantly minimizing wall film accumulation and avoiding the “fuel starvation” observed in closed-valve strategies. Additionally, OVI fully utilizes methanol’s latent heat to generate an intake cooling effect, which lowers the in-cylinder temperature and helps suppress knock. Furthermore, a dual-injector strategy is proposed to balance spatial atomization and rapid fuel transport, which achieves a 66.7% increase in the fuel amount entering the cylinder compared with the original strategy. This configuration effectively resolves the fuel induction lag, achieving stable combustion starting from the first cycle. Full article