Thermal Stress Research Articles

Coupling Indoor and Outdoor Heat Stress During the Hot Summer of 2022: A Case Study of Freiburg, Germany

Indoor and outdoor heat stress, which can appear during warm periods of the year, often has a negative impact on health and reduces productivity at work and study. Intense heat waves (HWs) are causing increasing rates of morbidity and mortality. This study aimed to analyze the coupling and delay of indoor and outdoor heat stress during HW events, using the example of ten workplaces (WPs) situated in different offices and buildings in the medium-sized city of Freiburg, Germany. The relationships between air temperature, humidity, and thermal stress intensity in the WPs were explored during HW periods. It was found that the level of thermal load in the investigated WPs was very different compared to that outdoors (during HWs and the entire summer). The mean physiologically equivalent temperature (PET) for the summer of 2022 inside the investigated offices was 2 °C higher than outside. All classes of thermo-physiological stress were observed outdoors at a meteorological station during the study period. While at eight of the ten workplaces, the most frequent physiological stress was slight heat stress (ranging between 62.4% and 97.4% of the time), the other two WPs were dominated by moderate heat stress (53.7% and 60.6% of the time). The daily amplitudes as well as diurnal courses of air temperature, humidity, and PET during the summer differed significantly at the ten different WPs. It is suggested to use vapor pressure instead of relative humidity to characterize and compare different HWs both outside and inside. It is proposed for future work research to analyze not only room and building characteristics but also the characteristics of the surroundings of the building for a better understanding of the key factors that influence human thermal comfort in different workplaces. A framework of the drivers affecting the coupling of outdoor and indoor heat stress is proposed.

Elevated developmental temperatures below the lethal limit reduce Aedes aegypti fertility.

Aedes aegypti mosquitoes are the principal vectors of dengue and continue to pose a threat to human health, with ongoing urbanization, climate change and trade all impacting the distribution and abundance of this species. Hot periods are becoming increasingly common and their impacts on insect mortality have been well established, but they may have even greater impacts on insect fertility. In this study, we investigated the impacts of high temperatures on Ae. aegypti fertility both within and across generations. Mosquitoes developing under elevated temperatures exhibited higher critical thermal maxima (CTmax), reflecting developmental acclimation, but their fertility declined with increasing developmental temperature. In females, elevated developmental temperatures decreased fecundity while in males it tended to decrease the proportion of eggs that hatched and the proportion of individuals producing viable offspring. Rearing both sexes at 35°C increased fecundity in the subsequent generation but effects of elevated temperatures persisted across gonotrophic cycles within the same generation. Moreover, exposure of adults to 35°C further decreased fertility beyond the effects of developmental temperature alone. These findings highlight sub-lethal impacts of elevated temperatures on Ae. aegypti fertility and plastic responses to thermal stress within and across generations. This has significant implications for predicting the distribution and abundance of mosquito populations thriving in increasingly warmer environments.

Delineating the emergence of thermally tolerant Symbiodiniaceae genotypes across the dominant coral species of a turbid reef: Adaptation and resilience strategy.

Climate change-induced rise in sea surface temperatures has led to an increase in the frequency and severity of coral bleaching events, ultimately leading to the deterioration of coral reefs, globally. However, the reef-building corals have an inherent capacity to acclimatize to thermal stress on pre-exposure to high temperatures by altering their endosymbiotic Symbiodiniaceae community composition towards a thermal tolerant composition. This reorganisation may become an important tool in coral's resilience to rapid environmental change. Therefore, it is crucial to delineate the Symbiodiniaceae community in our reef to predict their resilience capacity. Our study aims to analyse the symbiont community associated with common reef corals in a heat-stressed, marginal turbid reef of Palk Bay, India. We employed next-generation sequencing-based high-resolution analyses of internal transcribed spacer two (ITS2) amplicons within the SymPortal framework to examine the diversity and organization of Symbiodiniaceae communities. The results revealed a dominance of heat-tolerant Durusdinium (D1-D4) and Cladocopium (C15) across coral species (Acropora cytherea, Acropora digitifera, Favites abdita, and Porites lobata) and reef environment (seawater, and reef sediment), with the presence of 18 ITS2 type profiles in our samples. To our knowledge, this is the first comprehensive study to delineate Symbiodiniaceae communities at fine scale resolution (ITS2 type profile) from scleractinian corals in India, establishing a baseline for future research in a marginal reef ecosystem. Several studies have highlighted the importance turbid reefs as prospective climate refugia under the future threat of climate change. Therefore, this study is crucial for researchers, scientists, stakeholders, and policymakers to identify reef sites and coral species with resilience capacity for devising future reef restoration and management strategies.

The differential physiological responses to heat stress in the scleractinian coral Pocillopora damicornis are affected by its energy reserve.

The scleractinian corals conduct various responses upon heat stress such as bleaching and tissue loss, and colonies from the same coral species can conduct differential physiological activities with the biochemical basis unknown. In the present study, factors that influence the heat stress responses in coral Pocillopora damicornis were investigated. It was observed that P. damicornis conducted three differential physiological responses under heat treatment including tissue loss, bleaching, and polyp bailout. During heat response process, coral colonies conducting tissue loss had significantly higher total antioxidant capacity (T-AOC) level, while the bleached coral colonies exhibited higher caspase-3 activation level. Moreover, the stress response varied based on the energy reserve status. Colonies with higher lipid and sugar reserves were more likely to bleach, while those with lower reserves tended to undergo polyp bailout. We demonstrate that energy reserves influence the heat response patterns of P. damicornis. Colonies with higher lipid and sugar reserves may survive longer under heat stress, suggesting that these energy reserves contribute to their heat resistance. This study suggests that colonies with higher energy reserves prior to thermal stress may have greater thermal resistance, indicating that long-term environmental stressors that deplete energy reserves could increase susceptibility to thermal stress.

Modeling of temperature-dependent first matrix cracking stress in ceramic matrix composites considering fracture surface energy and residual thermal stress

Modeling of temperature-dependent first matrix cracking stress in ceramic matrix composites considering fracture surface energy and residual thermal stress

Daily time series of 12 human thermal stress indices in Greece, aggregated at commune level (1998–2022)

Daily time series of 12 human thermal stress indices in Greece, aggregated at commune level (1998–2022)

Long-term thermal stress reshapes the tolerance of head kidney of Hong Kong catfish (Clarias fuscus) to acute heat shock by regulating energy metabolism and immune response

Long-term thermal stress reshapes the tolerance of head kidney of Hong Kong catfish (Clarias fuscus) to acute heat shock by regulating energy metabolism and immune response

Jet fuel oxidation on conventionally and additively manufactured metallic tubes

Jet fuel oxidation on conventionally and additively manufactured metallic tubes

How does the coral microbiome mediate its natural host fitness under climate stress conditions? Physiological, molecular, and biochemical mechanisms.

Although the symbiotic partnership between corals and algal endosymbionts has been extensively explored, interactions between corals, their algal endosymbionts and microbial associates are still less understood. Screening the response of natural microbial consortiums inside corals can aid in exploiting them as markers for dysbiosis interactions inside the coral holobiont. The coral microbiome includes archaea, bacteria, fungi, and viruses hypothesized to play a pivotal vital role in coral health and tolerance to heat stress condition via different physiological, biochemical, and molecular mechanisms. The dynamic behaviour of microbial associates could denote their potential role in coral adaptation to future climate change, with microbiome shifts occurring independently as a response to thermal stress or as a response to host stress response. Associated adaptations include regulation of coral-algal-microbial interactions, expression of heat shock proteins, microbial composition changes, and accumulation of secondary metabolites to aid in sustaining the coral's overall homeostasis under ocean warming scenarios.

Thermal performance of a solar-assisted slinky foundation heat exchanger coupled with a heat pump in a cold climate

Thermal performance of a solar-assisted slinky foundation heat exchanger coupled with a heat pump in a cold climate

Beyond the Bioclimatic Chart: An Automated Simulation-Based Method for the Assessment of Natural Ventilation and Passive Design Potential

Beyond the Bioclimatic Chart: An Automated Simulation-Based Method for the Assessment of Natural Ventilation and Passive Design Potential

Assessing the impacts of coal-to-electricity transition in China's regional power system and "2+ 26" cities.

Compared to air pollution, the Coal to Electricity (CtE) policy's impacts on the power system are less discussed. As China transitions to carbon neutrality, unstable wind, and photovoltaic (PV) units exacerbate power dispatching challenges amid increased heating loads. We simulate the electric heating and cooking loads in the "2+ 26" cities and integrate them into a provincial power dispatch model to assess CtE's influence. CtE shows a slight CO2 reduction compared to heating with coal, potentially cutting emissions by up to two-thirds in high renewable energy scenarios. However, electricity prices fluctuate more in such scenarios, possibly increasing heating bills. CtE loads could increase the loss of load possibility in some provinces, especially with temperature drops and renewable capacity expansions. Overall, CtE places significant stress on the power system due to its additional loads and load fluctuations, requiring extra measures to ensure system adequacy amidst high wind and solar installations.

Rectal temperature and heat transfer dynamics in the eye, face, and breast of broiler chickens exposed to moderate heat stress.

This study aimed to characterize body temperature in finishing broiler chickens and to explore heat transfer dynamics under thermoneutral (TN) and heat stress (HS) conditions. To achieve this, 900 Ross 308 chicks were divided into TN and HS groups, with the HS group subjected to cyclical heat stress (30°C, 45 % RH) from day 28 to day 33 post-hatch. Rectal temperature (Tr) and skin temperature (Ts) at the face (Tsf), eye (Tse), and breast (Tsb) were measured. Tr ranged from 39.1 to 40.6°C under TN and from 40.4 to 43.2°C under HS (Pcondition < 0.001). Core-to-skin temperature gradients were lower under HS (P < 0.0001), indicating reduced heat transfer to the skin. All Ts parameters were higher under HS (P < 0.001), and skin-to-air temperature gradients were also lower (P < 0.0001), reflecting lower heat dissipation. Ts varied significantly across anatomical regions (P < 0.001), and core-to-skin and skin-to-air gradients differed between regions under both conditions (P < 0.001). Strong correlations were observed between Tr and Ts (r = 0.88, 0.89, and 0.92 for Tsb, Tse, and Tsf, respectively), suggesting Ts as a strong predictor of Tr. In conclusion, rectal temperatures in finishing broilers are more variable under HS than under TN. Under HS, some birds continue to exhibit Tr in the physiological range. Under TN, heat is transferred from the core to the eyes at a significantly higher rate than to the face and breast skin. However, the breast skin dissipates heat into the environment at a greater rate than the face and the eyes. These patterns of heat transfer between the core and the skin, and between the skin and the environment are conserved under HS. However, heat transfer rates are significantly reduced leading to increased heat load of the birds. These findings provide further insights into thermoregulation in broiler chickens.

Few-sample model training assistant: A meta-learning technique for building heating load forecasting based on simulation data

Few-sample model training assistant: A meta-learning technique for building heating load forecasting based on simulation data

A novel CALA-STL algorithm for optimizing prediction of building energy heat load

A novel CALA-STL algorithm for optimizing prediction of building energy heat load

A hybrid prediction model for heating load of buildings within residential communities considering occupancy rates

A hybrid prediction model for heating load of buildings within residential communities considering occupancy rates

Irish residential heating demand profile dataset.

This data article describes the operation of gas and oil fuelled residential heating systems in Ireland. Based on almost 10,000 homes, the data presents information on the operation of domestic heating systems (whether turned on/off by the user), and the firing of the boiler during 2-hour slots across a period of two years ending in September 2021 by geographical region. The electrification of heating is government policy, with the ambition that hundreds of thousands of homes will switch from oil and gas fuelled residential heating to heat pumps. Such an outcome will have implications for electricity generation, transmission and distribution, especially during peak demand periods. This dataset can be used as a starting point to examine how additional residential heating loads will impact on the electricity grid and provide insight on where electricity grid strengthening works should be prioritised.

Microscopic damage evolution and physical–mechanical behavior of high-temperature red sandstone under varying heating and cooling durations

The investigation into the cooling and heating duration is crucial for evaluating the aftermath of a fire incident. This study comprehensively analyzes the macroscopic and microscopic characteristics of red sandstone under high temperatures, heating, and cooling conditions, with temperatures ranging from 200 to 800 °C and heating/cooling durations ranging from 0.75 to 3 h and 0.5 to 54 h, respectively XRD and SEM techniques were employed to investigate mineral composition and microstructural changes. Multifactorial experiments explored the impact of these conditions on the rock’s physical properties and assessed mechanical properties such as peak stress, peak strain, and elastic modulus. Data fitting with MATLAB was used to construct a damage constitutive model. The findings show that elevated temperatures and prolonged heating significantly alter the microstructure and composition of red sandstone, including pore formation, void development, and structural modifications. Heating induces cracking, voids, and chemical reactions, with extended exposure leading to changes in feldspar minerals (K/Ca/Na). Temperature-dependent physical properties exhibit mass loss and density decline. Mechanical properties are substantially affected, with peak stress decreasing from 40 MPa to 6.94 MPa, and variations in peak strain and elastic modulus. Thermal stress at specific temperatures notably enhances compressive strength. The newly established constitutive model has an error within 5% compared to actual experimental results.

A review: On HPLC method for estimation of methylcobalamin

Methylcobalamin, a vital vitamin B12 analog, is susceptible to degradation under thermal stress, leading to changes in PH. Trigeminal neuralgia, diabetic neuropathy, facial paralysis and megaloblastic anemia can be treated by the use of Methylcobalamin injection. A new simple, precise, economically viable and efficient High-Performance Liquid Chromatographic (HPLC) method for the estimation of Methylcobalamin (MeB12) in bulk drugs and pharmaceutical dosage formulations was developed and validated. The method was validated for linearity, accuracy, precision, LOD, LOQ and robustness as per ICH guidelines. The method was tested with commercially available MeB12 drugs and the concentration methylcobalamine was found to be accurate.

Annual Garden Rocket and Radish as Microgreens: Seed Germination Response to Thermal and Salt Stress

Temperature and salinity level of the imbibition medium play a crucial role in regulating seed germination and seedling emergence, which is also true in microgreen production, where temperature and water potential may influence seed germination alone and/or in combination. In this study, the effects of different temperatures and water potentials in NaCl, alone or in combination, upon germination and early radicle growth, were assessed in two species for microgreen production (Eruca sativa-rocket, and Raphanus sativus-radish). Seeds were germinated at eight constant temperatures (from 5 to 35 °C) and five water potentials (ψ) in NaCl (from 0 to −1.2 MPa). Final germination percentage (FGP) was maximized at 15–20 °C in rocket, and at 20–25 °C in radish. As the temperature increased or decreased, germination was reduced and became less uniform, to a greater extent, at suboptimal temperatures in both species. Across water potentials, FGP values exceeding 50% at the highest temperature in radish indicated a greater tolerance than rocket to supraoptimal temperatures during germination. Across temperatures, FGP and germination speed in both species were progressively depressed as the water potential decreased. The adverse effects of NaCl progressively increased as the temperature moved away from its optimal value. Overall, rocket seeds were able to germinate well (&gt;80%) at 20 °C at salinity levels down to −0.9 MPa, while radish seeds were able to germinate well (≥90%) at 25 °C at salinity levels down to −0.9 MPa. Salt stress tolerance was higher in rocket and radish at low and high temperatures, respectively. Both thermal time and hydrotime requirements were higher in radish because its seeds took longer to germinate. Thermal time and hydrotime may help to predict the germination capacity and time, once the temperature or water potential of the imbibition substrate is known. The findings of this study have important implications for the large-scale industrial production of microgreens.