Effect Of High Temperature Research Articles

Negative Regulatory Role of Non-Coding RNA Vvi-miR3633a in Grapevine Leaves and Callus under Heat Stress

The grapevine, a globally significant fruit and an essential fruit tree species in China, is vulnerable to the adverse effects of high temperatures. Understanding the roles of microRNA and transcription factors in plant development and stress resistance is crucial for mitigating the impact of high temperature on grape growth and yield. This study investigates the response of miRNA to high-temperature stress in grape leaves. The expression level of Vvi-miR3633a was found to be inhibited under heat treatment in both Thompson seedless and Shen yue varieties, while its potential target genes (Vv-Atg36 and Vv-GA3ox2) were induced. Through transgenic overexpression experiments, it was demonstrated that Vvi-miR3633a plays a role in thermal response by affecting the expression of target genes. Furthermore, under heat stress conditions, overexpression of Vvi-miR3633a in grape callus decreased heat resistance compared to the control group (CK). The study also revealed that the target genes of Vvi-miR3633a regulate the expression of oxidase synthesis genes VvSOD and VvCAT, leading to reduced oxidase synthesis which may compromise the oxidation system. Additionally, the expression level of heat shock proteins in the transgenic lines was changed compared to the control (CK). Overall, this research provides valuable insights into understanding the molecular mechanisms involved in different crossing/breeding programs to produce heat-resistant grape varieties. Such varieties can be appropriate to propagate in warm climate areas with high temperature conditions.

Flash drought and heatwave compound events increased in strength and length from 1980 to 2022 in China

Compound flash drought and heatwave (FDHW) events have garnered increasing amounts of attention due to their substantial impacts on agriculture, water resources, and public health. However, studies on their intensity and classification in China are limited. In this study, we classified FDHW events in China from 1980 to 2022 using a classification framework designed to address regional patterns and explore their characteristics further. The results showed that FDHW events in northern China mostly occurred in early to mid-summer, whereas in southern China, excluding the Southwest River Basin, they occurred predominantly in mid to late summer. Furthermore, the spatial coverage of FDHW events across China significantly expanded. From 1980 to 2022, FDHW events in China evolved toward higher intensities and longer durations. This trend was especially notable in the Jiang-Huai River Basin, the main grain-producing region and a densely populated area of China. From the perspective of land‒atmosphere coupling, the amplifying effect of flash droughts and high temperatures increased with their intensity. When high temperatures reached the extreme level, the amplification effect on flash droughts was evident: 35.76% from the water deficit perspective and 38.82% from the soil moisture perspective. During extreme flash droughts, the amplification effect on high temperatures intensified: 41.51% from the water deficit perspective and 45.06% from the soil moisture perspective. The Southwest River Basin became a hotspot for the interaction between flash droughts and high temperatures. This study has implications for developing science-based policies to tackle risks in the water, energy and food sectors in China.

Theoretical study on the effect of temperature gradient on contact-free scanning for scanning ion conductance microscopy

Scanning ion-conductance microscopy (SICM) is a non-contact, high-resolution, and in-situ scanning probe microscope technique, it can be operated in probing the physical and chemical properties of biological samples such as living cells. Recently, using SICM to study the effects of microenvironment changes such as temperature changes on response of the biological samples has attracted significant attention. However, in this temperature gradient condition, one of the crucial but still unclear issues is the scanning feedback types and safe threshold. In this paper, a theoretical study of effect of the temperature gradient in electrolyte or sample surface on the SICM safe ion-current threshold is conducted using three-dimensional Poisson-Nernst-Planck, Navier-Stokes and energy equations. Two temperature gradient types, sample surface and two types of pipettes with different ratio of inner and outer radii are included, respectively. The results demonstrate that the local temperature of the electrolyte and then sample surface significantly affect the ion flow, shape of the approach curves and thus safe threshold in SICM pipette probe for contact-free scanning. There is a current-increased and decreased phases for approaching the surface with higher temperature and two current-decreased phases for surface with lower temperature. Based on this shape feature of approach curves, the change rate of current is analysis to illustrate the possibility for contact-free scanning of slope object. The results indicate that with the decrease of the normalized tip-surface distance, the coupling effect of large slope angle and local high temperature makes the increase in change rate of ion current not significant and then it challenging to realize contact-free scanning especially for higher surface temperature.

Hygroscopic hydrogel-based cooling system for photovoltaic panels: An experimental and numerical study

Thermal management is an essential aspect of photovoltaic (PV) system design because of the negative effects of high temperatures on the efficiency of PV panels. The use of hygroscopic hydrogels for the evaporative cooling of PV panels is an emerging technique that has attracted attention owing to the high latent heat and recyclability of these materials. However, a comprehensive understanding of the heat and mass transport mechanisms in hygroscopic hydrogels is necessary. Factors that would ensure the long-term performance of PV panel/hydrogel (PV/HG) systems under real-world conditions are still poorly understood, and the intrinsic properties of hydrogels and the effect thereof on their cooling performance have hitherto remained unexplored. Herein, we propose a mathematical model for hydrogel-cooled PV panels to study the heat and mass transfer mechanisms of PV/HG systems in practical environments. The model is used to examine the impact of the thermal conductivity, diffusion coefficient, and thickness of the hydrogel on the performance of the PV/HG system. Unlike previously reported approaches to enhance the efficiency, in this study, the external heat transfer resistance and internal mass transfer resistance were identified as the primary controlling factors. Enhancement of the thermal conductivity of the hydrogel is shown to have a limited effect on the performance, whereas improving the water diffusion within the hydrogel significantly boosts the system efficiency. Optimally, the thickness of the hydrogel must be such that it balances the heat and mass transfer distances with the available water volume. During the summer in Guangzhou, China, a 6-mm thick layer of hydrogel lowered the temperature of a PV cell by up to 7.5 °C to increase the daily power generation by 2.1%. Analysis of the nationwide situation showed that hydrogels have substantial potential for lowering the peak PV panel temperatures (by as much as 19.3 °C) to mitigate fluctuations in the output power. Our findings offer valuable insights into the design of PV/HG systems towards improving their performance.

Surviving global change: a review of the impacts of drought and dewatering on freshwater mussels.

The increase in the frequency and intensity of droughts and heatwaves caused by climate change poses a major threat to biodiversity. In aquatic systems, sedentary species such as freshwater mussels are generally considered more vulnerable to changes in habitat conditions than mobile species such as fish. As mussels provide important ecosystem services, understanding the impacts of drought on freshwater mussels is of particular importance for the management of overall functioning of aquatic ecosystems. We used a comprehensive literature search to provide a systematic overview of direct and indirect effects of drought on freshwater mussels (Bivalvia: Unionida) and an evaluation of mitigation strategies. We found that drought studies were concentrated mostly in the USA, with a focus on the Unionidae family. Topics ranged from the physiological effects of high temperatures, emersion, and hypoxia/anoxia to behavioural and reproductive consequences of drought and the implications for biotic interactions and ecosystem services. Studies spanned all levels of biological organization, from individual responses to population- and community-level impacts and ecosystem-wide effects. We identified several knowledge gaps, including a paucity of trait-based evaluation of drought consequences, limited understanding of thermal and desiccation tolerance at the species level, and the synergistic effects of multiple drought stressors on mussels. Although we found many studies provided suggestions concerning management of populations, habitat conditions, and anthropogenic water use, a systematic approach and testing of recommended mitigation strategies is largely lacking, creating challenges for managers aiming to conserve freshwater mussel communities and populations in light of climate change.

Effects of high temperature and strain rate on the impact-induced inter-laminar shear behavior of plain woven CF/PEEK thermoplastic composites

This paper aims to investigate the interlaminar shear properties and failure mechanisms of plain woven carbon fabric/polyetheretherketone (CF/PEEK) thermoplastic composites under high strain rate impact loads at different temperatures (25°C, 120°C, 295°C). A reliable hot air flow heating method with SHPB is creatively employed for short beam shear experiments. A multi-scale model was developed to predict the impact behavior of plain CF/PEEK composites. Both results show that the thermoplastic composites have strong strain rate and temperature dependence, and which are more sensitive to temperature effect. As the temperature increases, the thermoplastic composites are mainly affected by the softening effect of the matrix due to the glass transition temperature. The shear modulus and peak stress appear to decline at high temperatures, while the failure strain tends to increase. The damage mode changes from interlayer delamination cracking at the glassy state to shear fracture and fiber pullout at a highly elastic state. As the strain rate increases, the failure strain decreases, while the shear modulus and peak stress show the opposite trend. Fiber bundle breakage, debonding, matrix cracking, and significant interlayer delamination occur at high strain rates.

The neurocognitive mechanism linking temperature and humidity with miners' working memory: an fNIRS study.

In China's coal mines, employees work in environments reaching depths of 650 m, with temperatures around 40°C and humidity levels as high as 90%, adversely affecting their health, safety capabilities, and cognitive functions, especially working memory. This study aims to explore different temperature and humidity conditions' impact on neurocognitive mechanisms to enhance occupational health and safety. This study, conducted between June and August 2023, with 100 coalmine workers from the Hongliulin Mining Group, utilized functional near infrared spectroscopy (fNIRS) and short-term visual memory tasks to evaluate the effects of high temperatures and humidity on working memory by monitoring activity in the cerebral cortex. Behavioral data, and neurophysiological data were analyzed using Tukey's HSD for significant differences and multiple regression to explore the impact of temperature and humidity. The β-values of Oxy-Hb for different regions of interest were calculated using General liner model (GLM), and the activation maps were plotted by NIRS_KIT. High temperature and humidity (Condition IV) significantly depressed reaction times and working memory compared to other conditions, with temperature having a more pronounced impact than humidity on these cognitive measures (p < 0.05). Oxy-Hb concentration increased notably under Condition IV, emphasizing temperature's influence on brain oxygen levels. ROI analysis revealed varied brain activation patterns. The activation of ROI A and B (prefrontal cortex) increased with the increase of temperature and humidity, while ROI C (supplementary motor area) was less sensitive to temperature, indicating the complex influence of environmental factors on brain function. This study highlights the important effects of temperature and humidity on cognitive performance and brain function, highlighting the need to optimize the environment of miners' sites to improve productivity and safety.

Experimental study on mechanical properties and breakage of high temperature carbon fiber-bar reinforced concrete under impact load

To investigate the effects of high temperature and carbon fiber-bar reinforcement on the dynamic mechanical properties of concrete materials, a muffle furnace was used to treat two kinds of specimens, plain and carbon fiber-bar reinforced concrete, at high temperatures of 25, 200, 400 and 600 °C. Impact compression tests were carried out on two specimens after high-temperature exposure using a Hopkinson pressure bar (SHPB) test setup combined with a high-speed camera device to observe the crack extension process of the specimens. The effects of high temperature and carbon fiber-bar reinforcement on the peak stress, energy dissipation density, crack propagation and fractal dimension of the concrete were analyzed. The results showed that the corresponding peak strengths of the plain concrete specimens at 25, 200, 400, and 600 °C were 88.37, 93.21, 68.85, and 54.90 MPa, respectively, and the peak strengths after the high-temperature exposure first increased slightly and then decreased rapidly. The mean peak strengths corresponding to the carbon fiber-bar reinforced concrete specimens after high-temperature action at 25, 200, 400, and 600 °C are 1.13, 1.13, 1.21, and 1.19 times that of plain concrete, respectively, and the mean crushing energy consumption densities are 1.27, 1.31, 1.73, and 1.59 times that of plain concrete, respectively. The addition of carbon fiber-bar reinforcement significantly enhanced the impact resistance and energy dissipation of the concrete structure, and the higher the temperature was, the more significant the increase. An increase in temperature increases the number of crack extensions and width, and the high tensile strength of the carbon fiber-bar reinforcement and the synergistic effect with the concrete material reduce the degree of crack extension in the specimen. The fractal dimension of the concrete ranged from 1.92 to 2.68, that of the carbon fiber-bar reinforced concrete specimens ranged from 1.61 to 2.42, and the mean values of the corresponding fractal dimensions of the plain concrete specimens after high-temperature effects at 25, 200, 400, and 600 °C were 1.19, 1.21, 1.10, and 1.11 times those of the fiber-reinforced concrete specimens, respectively. The incorporation of carbon fiber-bar reinforcement reduces the degree of rupture and fragmentation of concrete under impact loading and improves the safety and stability of concrete structures.

Effects of High Temperature and High Humidity on the Degree of Ocular Damage Caused by 60 GHz Millimeter Wave Exposure.

Millimeter waves (MMW) are pervasive in society; however, studies on the biological effects of MMW exposure are usually performed in laboratory settings not reflecting global environmental diversity. We investigated the effects of a 6-min exposure to 60 GHz MMW (wavelength, 5.0 mm) at incident power densities of 200 and 300 mW cm-2 in eyes (exposed right eyes vs. unexposed left eyes) under various ambient temperature/relative humidity environments (24 °C/50%, 45 °C/20%, and 45 °C/80%) using an in vivo rabbit model. Correlations were examined with adverse ocular events, including corneal epithelial damage (assessed using fluorescein staining), corneal opacity (evaluated by slit-lamp microscopy), and corneal thickness (measured via optical coherence tomography). Our findings indicate that higher temperatures and humidity tend to exacerbate MMW-induced ocular damage, albeit not significantly in the present study. Further research with a larger sample size is warranted. Incident power density emerged as a factor that was directly linked to the ocular damage threshold. High ambient temperature and humidity tended to exacerbate ocular damage from MMW exposure, although the effect was secondary. Ocular damage in a high-temperature (45 °C), high-humidity (80%) environment was increased to the same extent as that by incident power density increased by approximately 100 mW cm-2 in an ocular damage model in a standard environment (24 °C, 50%). In a high-humidity environment, the internal ocular tissue temperature increased at a high ambient temperature of 45 °C, suggesting that the eyeball may respond differently compared to other tissues.

Microstructure and residual strength properties of engineered geopolymer composites (EGC) subjected to high temperatures

This study investigates the effects of high temperature on the microstructure and residual compressive strength properties of engineered geopolymer composites (EGC). The importance of this study focusses on the performance and durability of EGC, aiming towards sustainable construction practices. The proposed study fills the knowledge gap by the use of steel fibers (SF) as primary reinforcement in EGC, specifically involving a combination of Fly Ash (FA), Basic Oxygen Furnace (BOF) slag, and Iron Ore Tailings (IOT). The residual properties of EGC under high-temperature conditions were assessed by preparing cube specimens (50 mm) involving FA and BOF slag as primary precursors, with IOT as a partial replacement to conventional fine aggregate (M-sand) and brass-coated SF as discrete reinforcement. The specimens were exposed to temperatures up to 1000 °C in a muffle furnace in six different levels: 25, 200, 400, 600, 800, and 1000 °C. Post-exposure, the specimens were ambient cured prior to testing of pore structure distribution, residual strength properties, and microstructural characteristics involving scanning electron microscopy (SEM) analysis. The experimental findings show that, despite various combinations of precursors, IOT and SF, no explosive deterioration or spalling occurred in EGC mixes at any level of exposure. Also, as the exposure temperature increased, the compressive strength decreased while the strain capacity enhanced, denoting an increase in the stiffness of the EGC mixes. Notably, the SF maintained its structural integrity even at 1000 °C, which was consistent with the observed microstructural behavior. This indicates the proposed EGC exhibits excellent resistance to elevated temperatures and enhanced strain-hardening capacity. Overall, this research provides valuable insights into the residual properties and microstructural characteristics of FA: BOF: IOT-based EGC, highlighting its potential as a sustainable and fire-resistant building material. The outcomes contribute significantly to the existing knowledge on EGC and its application in environments exposed to high temperatures.

Impact of Temperature, Irradiation Duration on Performance of Organic/Ru-Dye/Inorganic Solar Cells

This study investigates the impact of ambient conditions on the performance of P3HT/Ru-dye/nc-TiO2 solar cells (TLSCs). It has been found that the increase of temperature and irradiation duration affect on the parameters of TLSCs. When the temperature was increased from 293 k to 393 k , the short circuit current density (Jsc ) and open circuit voltgae (Voc) decrease from 2.2 to 1.7 mA/cm2 and 0.7 V to 0.5 V respectively. That is attributed to the effect of high temperature on recombination of photo-generated charges and reduction of shunt resistance (Rsh ) in the TLSC. Moreover, we also present the effect of irradiation duration on performance of the TLSCs. The measurement reveals that Jsc decreased by 0.5 mA/cm2 while Voc decreased by ~ 0.18 V during 4800 s illumination. This decrease suggests the filling of traps or defects at the interface with photo-genertated charges. Finally, the maximum output power of TLSCs dropped by almost half within 6 days during a 20-day test because of affecting atmosphere moisture on the interface properties between dye/ nc-TiO2 and P3HT.

The thermal dependent biology of cultured lumpfish (Cyclopterus lumpus Linnaeus 1758): Differences due to temperatures during early life and how tolerance is measured

The use of lumpfish as a “cleaner fish” in Atlantic salmon aquaculture is increasing. However, during the summer months, there have been large-scale mortalities of lumpfish at some North Atlantic salmon sea-cage sites. There is evidence that manipulating temperatures during early life can improve the thermal tolerance of fishes. Thus, we reared lumpfish embryos (eggs), larvae and juveniles under different temperature regimes, and measured their metabolic physiology and upper thermal limits, with the goal of better understanding their physiology and mitigating the effects of high summer water temperatures on their welfare. The specific incubation (egg) / rearing temperature combinations were 6 °C / 9 °C (normal production temperatures), 8.5 °C / 9 °C, 6–11 °C / 9 °C, 8.5 °C / 9–11 °C and 6–11 °C / 9–11 °C; with a range of temperatures indicating that fish were exposed to stochastic temperature changes.Hatching success was 61 % in the control (6 °C) group, as compared to ~47 % and 26.5 % in the groups exposed to 8.5 °C and the stochastic temperature regime (6–11 °C), respectively. Groups exposed to stochastic incubation and rearing temperatures also had the lowest survival rate (33.7 %) as opposed to those incubated and reared at constant temperatures (66.1 and 50.7 %) when unexpectedly exposed to high, and variable, ambient water temperatures that were experienced for roughly 7 weeks during rearing (due to abnormal water temperatures in the bay supplying our aquaculture facility). Interestingly, the critical thermal maximum (CTMax), incremental temperature maximum (ITMax) and metabolic capacity (i.e., aerobic scope) of 30-40 g lumpfish did not differ between the groups, and the first two parameters on average were 22.85 ± 0.12 °C and 20.63 ± 0.02 °C, respectively.

Effect of low sunlight and high temperature during flower bud differentiation on the cut flower quality of carnation ‘Cherry Tessino’

Effect of low sunlight and high temperature during flower bud differentiation on the cut flower quality of carnation ‘Cherry Tessino’

Experimental study on effect of grouting and high temperature on the anisotropic compressive strength behaviour of soft jointed rocks with an impersistent flaw

This study investigates the effect of different in situ conditions like flaw infill, heat-treatment temperatures, and sample porosities on the anisotropic compressive response of jointed samples with an impersistent flaw. Jointed samples of different porosities are prepared by mixing Plaster of Paris (POP) with different water contents, i.e. 60% (i.e. for lower porosity) and 80% (i.e. for higher porosity). These samples are grouted with different infill materials, i.e. un-grouted, cement and sand-cement (3:1)-bio-concrete (SCB) mix and subsequently subjected to different temperatures, i.e. 100 °C, 200 °C and 300 °C. The results reveal the distinct stages in the stress-strain responses of samples characterized by initial micro-cracks closure, elastic transition, and non-linear response till peak followed by a post-peak behaviour. The un-grouted samples exhibit their lowest strength at 30° joint orientation. The ratios of maximum to minimum strength are 3.11 and 3.22 with varying joint orientations for lower and higher porosity samples, respectively. Strengths of cement and SCB mix grouted samples are increased for all joint orientations ranging between 16.13%-69.83% and 18.04%–73% at low porosity and 22%–48.66% and 27.77%–51.57% at high porosity, respectively as compared to the un-grouted samples. However, the strength of the grouted samples is decreased by 66.94%–75.47% and 77.17%–81.05% at lower porosity, and 79.37%–82.86% and 81.29%–95.55% at higher porosity for cement and for SCB grouts with an increase in the heating temperature from 30 °C to 300 °C, respectively. These observations could be due to the suppression of favourable crack initiation locations, i.e. flaw tips along the samples due to the filling of the crack by grouting and generation of thermal cracks with temperature. The mechanism of strength behaviour is elucidated in detail based on fracture propagation analysis and the anisotropic response of with or, without grouted samples.

Study on the influence of high-temperature thermochemical nonequilibrium effects on the flow field characteristics around shaped wing

With advances in research on hypersonic vehicles, the precise simulation of the effects of thermochemical non-equilibrium has become increasingly important in their design. In light of this, this study explores the influence of high-temperature thermochemical non-equilibrium on the characteristics of the flow field around the hypersonic wings of an aircraft. We initially conducted a numerical simulation by using the model of flow through a cylinder to validate the accuracy and reliability of an 11-species gas model in representing high-enthalpy flow fields. Subsequently, a systematic analysis was conducted on the impact of thermochemical nonequilibrium effects on the temperature, pressure, and enthalpy distribution in the flow field around a symmetric diamond wing under different Mach numbers and angles of attack. The research results indicated that the deeper reason behind the differing thermochemical nonequilibrium effects in the flow field at various Mach numbers lies in the distinct distribution of enthalpy of the air components at different locations, which provided a new perspective for understanding flow field variations from the standpoint of enthalpy. It is disclosed that the thermochemical non-equilibrium significantly altered the characteristics of the flow field, particularly at high Mach numbers and angles of attack, with a significant impact on the aerodynamic parameters of both the windward and the leeward sides of the wing. Through explaining the mechanisms of thermochemical non-equilibrium under flow fields with different structures, this study provides a theoretical foundations for and a fresh perspective on the design of hypersonic vehicles.

Dual-Wave ZnO Film Ultrasonic Transducers for Temperature and Stress Measurements.

ZnO film ultrasonic transducers for temperature and stress measurements with dual-mode wave excitation (longitudinal and shear) were deposited using the reactive RF magnetron sputtering technique on Si and stainless steel substrates and construction steel bolts. It was found that the position in the substrate plane had a significant effect on the structure and ultrasonic performance of the transducers. The transducers deposited at the center of the deposition zone demonstrated a straight columnar structure with a c-axis parallel to the substrate normal and the generation of longitudinal waves. The transducers deposited at the edge of the deposition zone demonstrated inclined columnar structures and the generation of dominant shear or longitudinal shear waves. Transducers deposited on the bolts with dual-wave excitation were used to study the effects of high temperatures in the range from 25 to 525 °C and tensile stress in the range from 0 to 268 MPa on ultrasonic response. Dependencies between changes in the relative time of flight and temperature or axial stress were obtained. The dependencies can be described by second-order functions of temperature and stress. An analysis of the contributions of thermal expansion, strain, and the speed of sound to changes in the time of flight was performed. At high temperatures, a decrease in the signal amplitude was observed due to the decreasing resistivity of the transducer. The ZnO ultrasonic transducers can be used up to temperatures of ~500 °C.

Assessing the effects of high temperature on physiological disorders in peach fruit (Prunus persica L.)

Assessing the effects of high temperature on physiological disorders in peach fruit (<i>Prunus persica</i> L.)

The influence of the dopant concentration and sintering parameters on properties of antimony doped barium stannate ceramics

In this paper, the influence of antimony concentration and different sintering techniques on the structural, microstructural, and electrical properties of antimony-doped barium stannate, BaSn1-xSbxO3 (BSSO, x = 0.00, 0.04, 0.06, 0.08 and 0.10) was investigated. BSSO-based ceramic samples were obtained by conventional and spark plasma sintering. The XRD analysis confirmed the single-phase, cubic BaSnO3 lattice system in all conventionally sintered samples. Apart from the dominant cubic phase, the spark plasma sintering conditions led to the formation of a secondary phase, Ba2SnO4, in all samples. FESEM analysis revealed the presence of low angle grain boundaries (LAGBs) in BSSO samples with high antimony concentration (x = 0.08), independently of the sintering technique. However, the fraction of LAGBs is significantly higher in the BaSn0.92Sb0.08O3-SPS sample due to the simultaneous exposure of the conductive sample to the effects of high temperature and pressure during sintering process. These boundaries have low activation energy and allow free charge carrier transport through the grain boundary region. The high dopant concentration and the presence of large fraction of LAGBs in BaSn0.92Sb0.08O3-SPS sample reflected on its electrical properties through low and almost temperature-independent electrical resistivity in the temperature range of 25–150 °C.

High-temperature responses of Myzus persicae and its parasitoid Aphidius gifuensis in relation to heat level, duration and developmental stage.

Understanding how parasitoids respond to temperature is crucial for improving biological control strategies under the context of global warming. This study examined the suitability of Myzus persicae and its parasitoid Aphidius gifuensis to varying temperature conditions, as well as the stage-specific response of A. gifuensis to high temperatures. High temperatures had a significant impact on the both M. persicae and A. gifuensis. When exposed to 36°C, M. persicae developed more slowly and produced smaller adults compared to control, regardless of the duration of exposure (2, 4 or 6 h); additionally, the survival rate of M. persicae nymphs sharply decreased under these conditions. Exposure to 36°C for 4 h negatively impacted the development of A. gifuensis. Female parasitoids exposed to 32°C developed into smaller adults, whereas males exposed to all three temperature levels were smaller compared to control group. Female parasitoids exposed to high temperatures, regardless of the specific heat level and duration, exhibited reduced longevity and decreased fecundity. None of the parasitoids exposed to 36°C for 6 h daily developed into adults. Heat treated during early developmental stages (2 and 4 days old) had a greater influence on parasitoid development, whereas heat treatment at 4 and 6 days old had a more significant impact on its fecundity. High temperatures not only directly affected the performance of A. gifuensis, but also exerted indirect effects by influencing the quality of the host aphids M. persicae. The deleterious effects of high temperature on larvae can persist into the adult stage, affecting the longevity and reproduction of adults. These findings are important for the utilization of A. gifuensis in the control of M. persicae in warming environments. © 2024 Society of Chemical Industry.

Effect of temperature and oxidative atmosphere on the oxidation behavior of yttrium-containing ceramics

Yttrium-containing ceramics exhibit excellent resistance to water-oxygen corrosion, making them an attractive choice as the modified matrix for SiCf/SiC composites. However, the oxidation products of yttrium-containing ceramics are complex and vary widely in performance. In this study, YSOC ceramics, which are composed of yttrium silicate, SiO2, and SiC, were prepared using Y2O3, SiO2, SiC, and Li2CO3. This research investigated the effects of high temperatures, air oxidation, and water-oxygen corrosion on the phase compositions of YSOC ceramics. The influence of environmental factors on the synthesis and decomposition of yttrium silicate was analyzed. Moreover, the study explored the compatibility of different oxidation products with SiC. The results suggest that Y2SiO5 and Y2Si2O7 are formed through the low eutectic of SiO2, Y2O3, and Li2CO3. The high SiO2 content likely contributes to the relatively low formation temperature of Y2Si2O7. In the oxidizing environment, Y2SiO5 reacts with SiO2 to produce Y2Si2O7. Conversely, in the water vapor-containing atmosphere, Y2Si2O7 undergoes hydrolysis to form Y2SiO5. Y2Si2O7 displays a reduced elastic modulus in comparison to SiC fibers and exhibits favorable physical and chemical compatibility with SiC fibers. However, the hydrolysis of Y2Si2O7 may potentially affect the water-oxygen corrosion resistance of the ceramics. These findings will significantly advance research and enhance understanding of the water-oxygen corrosion behaviors of yttrium-containing matrix-modified composites.