Search Results (1,562)

Missile-borne active phased array antennas have been widely used in missile guidance for their beam agility, multifunctionality, and strong anti-interference capabilities. However, due to space constraints on the platform and difficulty in heat dissipation, the thermal power consumption of the antenna array can easily lead to excessive temperature, causing two primary issues: first, temperature-induced drift in T/R components, resulting in amplitude and phase errors in the feed current; second, temperature-dependent ripple voltage in the array’s secondary power supply, which exacerbates feed errors. Both issues degrade the electromagnetic performance of the array antenna. To mitigate these effects, this paper investigates feed errors and compensation methods in high-temperature environments. First, a synchronous Buck circuit ripple coefficient model is developed, and an electromagnetic–temperature coupling model is established, incorporating temperature-dependent feed current characteristics, and the law of electromagnetic performance changes is analyzed. On this basis, an electromagnetic performance compensation method based on a genetic algorithm is proposed to optimize the quantization compensation amount of the amplitude and phase of each element under the effect of high temperature. Full article

Hylocereus undatus growth is limited by long-term heat stress, and heat shock protein 70 (Hsp70) is crucial in the plant’s heat stress (HS) response. In a previous study, transcriptomic data revealed that Hsp70 family members in pitaya seedlings respond to temperature changes. This study identified 27 HuHsp70 genes in pitaya, analyzed their physicochemical properties (such as molecular weight and isoelectric point), and divided them into five subfamilies with conserved gene structures, motifs (short conserved sequence patterns), and cis-acting elements (regulatory DNA sequences). The Ks value (synonymous substitution rate) ranged from 0.93~3.54, and gene duplication events occurred between 71.17 and 272.19 million years ago (Mya). Under HS, eight and nine differentially expressed genes (DEGs) were detected at 24 h and 48 h, respectively. Quantitative real-time PCR (qRT-PCR, a method for measuring gene expression) verified the expression trends, with HuHsp70-11 expression increasing with heat shock duration, indicating that HuHsp70-11 is a key candidate. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses revealed that HuHsp70s, especially HuHsp70-11, play key roles in responding to high temperatures (HT) in H. undatus seedlings. A potential model by which HuHsp70-11 removes excess reactive oxygen species (ROS) and enhances cell membrane permeability was constructed. These results provide new perspectives for exploring the HS response mechanisms and adaptability of H. undatus plants to heat stress. Full article

To identify and evaluate the failure issues in the livestock manure-to-biomethane supply chain, this study employs a Bayesian network approach with three inference analysis methods: diagnostic analysis, sensitivity analysis, and maximum causal chain inference. First, the main hazard categories affecting the failure of the supply chain are identified, establishing risk indicators for feedstock collection, pretreatment, anaerobic digestion, purification and upgrading, transportation, and biomethane end-use. Then, the half-interval method and possibility superiority comparison are used to calculate and rank the severity of related accidents, obtaining the severity ranking of secondary indicators as well as the severity ranking of work items and risk items. Finally, Bayesian forward inference is applied to investigate the failure probability of the supply chain, combined with backward inference to identify the risk factors most likely to cause supply chain failures and trace the formation of failure hazards. The Bayesian sensitivity analysis method is ultimately applied to determine the key hazards affecting supply chain failures and the correlations between accident hazards, followed by validation. The results show that the failure probability of the supply chain through causal inference is approximately 54.76%, indicating relatively high failure risk. The three factors with the highest posterior probabilities are mechanical stirring failure C₃ (88.11%), corrosion-induced ammonia leakage poisoning D6, and equipment explosion caused by excessive pressure due to overheating during dehumidification heating D₉, which are the hazards most likely to cause failures in the supply chain. Improper operations and the toxicity of related chemicals are key hazards leading to supply chain failures, with the correlation between accident hazards presented as a hazard chain by integrating severity and accident probability, and the key risk points in the supply chain are identified. Full article

To promote the sustainable utilization of agricultural solid waste, this study proposes a novel approach for reinforcing soft clay using a peanut ash (PA)–cement composite stabilizer. The unconfined compressive strength (UCS) of pure cement and PA–cement composite systems was tested at curing ages of 3, 7, and 28 days, while the durability of the stabilized clay was evaluated through dry–wet cycling. Given that PA is rich in pozzolanic components, its addition may influence the hydration process of cement. Therefore, hydration heat analysis was conducted to examine the early hydration behavior, and XRD and TG analyses were employed to identify the composition and quantity of hydration products. SEM observations were further used to characterize the microstructural evolution of the stabilized matrix. By integrating mechanical and microstructural analyses, the solidification mechanism of the PA–cement stabilizer was elucidated. Mechanical test results indicate that the reinforcing effect increases with the stabilizer dosage. Pure cement exhibited superior strength at 3 days; however, after 7 days, specimens incorporating 5% PA showed higher strength than those stabilized solely with cement. At 28 days, the UCS of the 15% cement + 5% PA specimen reached 3.12 MPa, 11.03% higher than that of the 20% cement specimen and comparable to the 25% cement specimen (3.15 MPa). After five dry–wet cycles, the strength reduction of the 15% cement + 5% PA specimen was 22.76%, compared to 31.31% for the 20% cement specimen, indicating improved durability. Microscopic analyses reveal that PA reduces hydration heat and does not participate in early hydration, leading to lower early strength. However, its pozzolanic reactivity contributes to secondary hydration at later stages, promoting the formation of additional C-S-H gel and ettringite. These hydration products fill the inter-lamellar pores of the clay and increase matrix density. Conversely, excessive PA content (≥10%) exerts a dilution effect, reducing the amount of hydration products and weakening the mechanical performance. Overall, the use of an appropriate PA dosage in combination with cement enhances both strength and durability while reducing cement consumption, providing an effective pathway for the high-value utilization of agricultural solid waste resources. Full article

To promote the transition to a cleaner energy structure and support the achievement of the “carbon peak and carbon neutrality” goals, concentrated solar power (CSP) technology has attracted increasing attention. The molten salt globe valve, as a key control component in CSP systems, faces significant challenges related to low-temperature salt crystallization and thermal stress control. This study proposes an active electromagnetic induction heating method based on a triangular double-helix cross-section coil to address issues such as molten salt blockage in the seal bellows and excessive thermal stress during heating. First, electromagnetic simulation comparisons show that the ohmic loss of the proposed coil is approximately 3.5 times and 1.8 times higher than that of conventional circular and rectangular coils, respectively, demonstrating superior heating uniformity and energy efficiency. Second, transient electromagnetic-thermal-fluid-structure multiphysics coupling analysis reveals that during heating, the temperature in the bellows seal region stabilizes above 543.15 K, exceeding the solidification point of the molten salt, while the whole valve reaches thermal stability within about 1000 s, effectively preventing local solidification. Finally, thermal stress analysis indicates that under a preheating condition of 473.15 K, the transient thermal shock stress on the valve body and bellows is reduced by 266.84% and 253.91%, respectively, compared with the non-preheating case, with peak stresses remaining below the allowable stress limit of the material, thereby significantly extending the service life of the valve. This research provides an effective solution for ensuring reliable operation of molten salt valves and improving the overall performance of CSP systems. Full article

Heat stress represents a pervasive welfare challenge for beef cattle and other species in tropical and subtropical regions. While its physiological and production impacts are well-documented, quantitative measures of the welfare impact of heat stress remain absent. This study provides the first quantification of the welfare impact of heat stress in beef cattle (mostly Nelore), estimated as cumulative time in thermal discomfort of four intensities (Annoying, Hurtful, Disabling, Excruciating) using the Welfare Footprint Framework. We analyzed climate data from 636 locations over five years across major beef production areas in Brazil, Argentina, Colombia, Paraguay, and Uruguay. Daily heat stress episodes and chronic heat stress exposure were assessed, respectively, using Comprehensive Climate Index (CCI) levels and the Annual Thermal Load metric, which sums daily excesses above a threshold of thermal comfort (CCI = 30 °C) throughout the year, classifying locations into five risk categories. Welfare impacts were estimated for thirteen heat stress scenarios modeled by considering each CCI level within each thermal risk category. Beef cattle in moderate-risk regions were estimated to experience primarily mild thermal discomfort for an average of 5 h daily. This duration increased to an average of 7 h daily in high-risk areas, of which 4.5 h in moderate to intense thermal discomfort (Hurtful or higher). Very high-risk regions reached 10 h of daily thermal discomfort, while extreme-risk regions showed beef cattle facing heat stress for over 11 h on 307 days annually, including over 3 h per day under severe thermoregulatory effort. Overall, 65% of animals were in regions of high thermal risk or above, experiencing between 280 and 2800 h annually in moderate to intense thermal discomfort—a magnitude that places heat stress among the most significant welfare challenges in animal production. Shade provision reduced time in severe discomfort of Disabling intensity by 85% (from 578 to 83 h annually), with economic returns of US$12–16 per animal and payback periods of approximately 16 months. By quantifying welfare impacts as cumulative time in thermal discomfort, shade provision emerges as one of the most effective welfare interventions available for beef cattle, and likely other grazing ruminants, in tropical and subtropical regions. Full article

White Spot Syndrome Virus (WSSV) remains one of the most devastating pathogens in global shrimp aquaculture, causing massive economic losses annually. This study employed comparative transcriptomics to elucidate the molecular basis of the differential resistance to WSSV between the highly susceptible Pacific white shrimp (Litopenaeus vannamei) and the remarkably resistant oriental river prawn (Macrobrachium nipponense). Our analysis of gill, hepatopancreas, and muscle tissues at 24 h post-infection revealed fundamentally distinct defense strategies. The resistant M. nipponense employs a unique “proactive homeostatic reinforcement” strategy, characterized by significant enrichment of pathways central to cellular homeostasis, including signal transduction, cellular processes, and transport/catabolism. This approach, supported by coordinated up-regulation of heat shock proteins and structural genes, enables effective viral control without triggering excessive immune activation. In contrast, susceptible L. vannamei displays either widespread metabolic dysregulation leading to systemic collapse in moribund individuals or dependency on specific immune pathways (Toll-like receptor signaling and apoptosis) in survivors. Through comparative KEGG analysis, we identified heat shock protein 70 kDa (HSP70, K03283) as a key conserved gene and functionally validated its critical role in antiviral defense using RNA interference. Knockdown of HSP70 in M. nipponense significantly increased cumulative mortality and viral load, confirming its essential protective function. These findings provide novel insights into crustacean antiviral immunity and identify promising genetic targets for breeding WSSV-resistant shrimp strains, offering sustainable solutions for disease management in aquaculture. Full article

The present work uses numerical methods to explore the impact of spatial orientation on the behavior of molten pool and thermal responses during the laser–Cold Metal Transfer (CMT) hybrid additive manufacturing of metallic cladding layers. Based on the traditional double-ellipsoidal heat source model, an adaptive CMT arc heat source model was developed and optimized using experimentally calibrated parameters to accurately represent the coupled energy distribution of the laser and CMT arc. The improved model was employed to simulate temperature and velocity fields under horizontal, transverse, vertical-up, and vertical-down orientations. The results revealed that variations in gravity direction had a limited effect on the overall molten pool morphology due to the dominant role of vapor recoil pressure, while significantly influencing the local convection patterns and temperature gradients. The simulations further demonstrated the formation of keyholes, dual-vortex flow structures, and Marangoni-driven circulation within the molten pool, as well as the redistribution of molten metal under different orientations. In multi-layer deposition simulations, optimized heat input effectively mitigated excessive thermal stresses, ensured uniform interlayer bonding, and maintained high forming accuracy. This work establishes a comprehensive numerical framework for analyzing orientation-dependent heat and mass transfer mechanisms and provides a solid foundation for the adaptive control and optimization of laser–CMT hybrid additive manufacturing processes. Full article

Salinity has been recognized as one of the major environmental stresses that restrict the growth and quality of celery (Apium graveolens L.). Therefore, this study investigates the impact of different NaCl concentrations on celery growth and photosynthetic characteristics, as well as the potential regulatory role of exogenous trehalose application in mitigating the stress-induced effects. The results indicated that an increase in NaCl concentration from 50 to 200 mM markedly inhibited the growth of celery plants compared to that under control conditions. The application of different concentrations of trehalose mitigated the inhibitory effects of salt stress (100 mM NaCl) on celery growth and photosynthesis. Among the different trehalose treatments, T3 (10 mM trehalose) exhibited the most significant effects, increasing the aboveground biomass, belowground biomass, plant height, chlorophyll a, chlorophyll b, total chlorophyll, and net photosynthetic rate compared to that of salt stress alone, respectively. Furthermore, trehalose treatments enhanced the various fluorescence parameters, including the maximum efficiency of PSII photochemistry (Fv/Fm), coefficient of photochemical quenching (qP), fluorescence intensity, and photosynthetic performance index (PIabs) under salt stress. Meanwhile, trehalose reduced intercellular carbon dioxide concentration, excess excitation energy (1-qP)/NPQ, heat dissipation per unit area (DIo/CSm), and energy dissipated per reaction center (DIo/RC). Additionally, the results of principal component analysis (PCA) and membership function comprehensive evaluation indicate that an appropriate concentration of trehalose positively alleviates the salnitiy-induced effects in celery. Overall, the T3 demonstrated the most promising effects on mitigating the effects of salt stress by decreasing the excess excitation energy of PSII in celery leaves through the heat dissipation pathway. This reduction lowers the excitation pressure on the reaction centers, enhances the activity of PSII reaction centers per unit cross-section, and improves photosynthesis activity, thereby improving the growth of celery plants under salt stress. Full article

Ginseng is widely regarded as the “King of Herbs” in traditional Chinese medicine. In recent years, escalating global warming and intensified human activities have led to a continuous rise in environmental temperatures, posing a significant threat to ginseng cultivation in China. Therefore, understanding how high-temperature stress affects the photosynthetic performance of ginseng is essential for developing efficient and sustainable cultivation practices. In this study, four temperature regimes were established to systematically investigate the impact of elevated temperatures on the photosynthetic system of ginseng leaves: 25/16 °C (CK), 30/20 °C, 35/24 °C, and 40/28 °C (day/night). The results demonstrated that high-temperature stress significantly inhibited photosynthesis. Specifically, the activities of key chlorophyll biosynthesis enzymes—porphobilinogen deaminase and delta-aminolevulinate dehydratase—were markedly reduced, resulting in the accumulation of critical intermediates in the chlorophyll pathway, including protoporphyrinIX, Mg-protoporphyrinIX, and protochlorophyll. Chlorophyll synthesis was severely impaired as a result. Consequently, the contents of chlorophyll a, chlorophyll b, and carotenoids declined by 25.38%, 12.52%, and 54.63%, respectively, indicating substantial disruption of the photosynthetic pigment system. Anatomical observations revealed that high-temperatures induced stomatal closure, impairing stomata exchange and further reducing photosynthetic efficiency. Moreover, chloroplast ultrastructure was severely compromised, characterized by excessive accumulation of osmiophilic granules, disorganized and loosely stacked thylakoid membranes, and impaired capacity for light energy capture and conversion. This study provides theoretical insights into the response mechanisms of ginseng leaf photosynthesis under heat stress and establishes a scientific basis for enhancing thermotolerance through breeding programs and improved cultivation management strategies. Full article

Welding of high-carbon rail steels is widely applied in railway maintenance to restore worn rail surfaces and extend service life. However, the weldability of these steels is limited by their high carbon content and susceptibility to brittle microstructures in the heat-affected zone. This paper evaluates the quality of weld deposits applied to different grades of railway rails (UIC 1100, UIC 900A, and UIC HSH) using submerged arc welding (SAW) and flux-cored arc welding (FCAW) technologies with various filler materials. Weld quality was assessed through macrostructural examination, HV30 hardness measurements, and microstructural analysis. The results show that inappropriate combinations of filler materials and welding parameters lead to excessive hardness and martensitic structures, which are undesirable for in-service performance. In contrast, selected multi-layer welding procedures produced bainitic or tempered microstructures with favourable hardness distributions. Based on the experimental results, optimal welding procedures and filler material combinations for rail renovation are proposed. Full article

The paper provides a comprehensive overview of stray losses in conductive structural parts of power transformers, addressing the effects of stray magnetic fields on simple conductive plates, the distribution of additional losses across structural components and measures for their reduction. It examines the (im)possibility of directly measuring stray losses and presents methods for their indirect measurement, highlighting the generation of fault gases due to thermal faults and the importance of understanding multiphysical (electromagnetic–thermal) coupling in calculating stray losses. A problem rarely mentioned in the literature but confirmed here by measurements, is the excessive heating of the connecting elements of the clamping system caused by circulating currents. Full article

Agrivoltaics (APV) offers a promising dual land-use solution for food and energy production, yet empirical data regarding its impact on leguminous crops in tropical monsoon climates remain limited. This study evaluated the microclimate, growth, and yield of soybean (Glycine max) under an APV system compared to an open-field control during the wet and dry seasons in Bogor, Indonesia. The APV structure reduced incident solar radiation by approximately 35%, significantly lowering soil temperatures and maintaining higher soil moisture across both seasons. In the wet season, the APV treatment significantly increased grain yield (3528.8 vs. 1708.3 kg ha⁻¹, +106%) relative to the open field by mitigating excessive heat and radiative loads, which enhanced pod retention. In the dry season, APV maintained a yield advantage (2025.6 vs. 1724.4 kg ha⁻¹, +17%), driven by improved water conservation and a higher harvest index. Notably, shading did not delay phenological development or hinder vegetative growth in either season. These findings demonstrate that APV systems can contribute to sustainably higher yields and stability in tropical environments by buffering against season-specific environmental stresses, suggesting a viable pathway for sustainable agricultural intensification in equatorial regions. Full article

Global warming is increasingly constraining plant productivity by altering the photosynthetic energy balance and leaf thermoregulation. Under high light and elevated temperatures, absorption of energy in excess (AEE) by photosystem II disrupts photosynthetic electron transport, oxygen evolution, and CO₂ assimilation, often accompanied by reduced foliar transpiration. These conditions promote photoinhibition, as reflected by a decrease in maximal photosynthetic efficiency (Fv/Fm), an increase in non-photochemical quenching (NPQ), and photooxidative stress associated with enhanced reactive oxygen species (ROS) production. In addition to environmental heat stress, AEE influences foliar temperature through internal energy partitioning, including regulated dissipation of AEE as heat and changes in transpirational cooling. The relative contributions of NPQ, photochemistry, and transpiration to leaf temperature regulation are strongly context dependent and vary with light intensity, temperature changes, and water availability. Under global warming, rising background temperatures and increased vapor pressure deficit may constrain transpirational cooling and alter the balance between non-photochemical and photochemical energy dissipation and usage, respectively. In this review, we synthesize current knowledge on AEE handling, photoinhibition, NPQ and other quenching processes, and on transpiration cooling, and discuss a conceptual framework in which sustained imbalance among these processes under global warming conditions could amplify foliar heat stress and increase the risk of cellular damage. Rather than proposing new physiological mechanisms, this work integrates existing evidence across molecular, leaf, and ecosystem scales to highlight potential feedbacks relevant to plant performance under future climate prediction scenarios. Full article

The planetary boundary layer (PBL) exerts strong control on heat, moisture, and momentum exchange, yet its representation over the steep mountains and deep valleys of Liangshan remains poorly understood. This study evaluates six Weather Research and Forecasting (WRF) PBL schemes (ACM2, BL, MYJ, MYNN2.5, QNSE, and YSU) using multi-source observations from radiosondes, surface stations, and wind profiling radar during clear-sky dry-season cases in spring and winter. The schemes exhibit substantial differences in governing turbulent mixing and stratification. For the specific cases studied, QNSE best reproduces 2 m temperature in both seasons by realistically capturing nocturnal stability and large diurnal ranges, while non-local schemes overestimate nighttime temperatures due to excessive mixing. MYNN2.5 performs robustly for boundary layer growth in spring, and BL aligns most closely with radar-derived PBL height (PBLH). Vertical profile comparisons show that QNSE and MYJ better represent the lower–middle level thermodynamic structure, whereas all schemes underestimate extreme near-surface winds, reflecting unresolved terrain-induced variability. PBLH simulations reproduce diurnal cycles but differ in amplitude, with QNSE occasionally producing unrealistic spikes. Overall, no scheme performs optimally for all variables. However, QNSE and MYNN2.5 show the most balanced performance across seasons. These findings provide guidance for selecting PBL schemes for high-resolution modeling and fire–weather applications over complex terrain. Full article