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1. Asymmetry of thermal sensitivity and the thermal risk of climate change

   https://doi.org/10.1111/geb.13570  

   Buckley, Lauren B.; Huey, Raymond B.; Kingsolver, Joel G. (July 2022, Global Ecology and Biogeography)

   Abstract AimUnderstanding and predicting the biological consequences of climate change requires considering the thermal sensitivity of organisms relative to environmental temperatures. One common approach involves ‘thermal safety margins’ (TSMs), which are generally estimated as the temperature differential between the highest temperature an organism can tolerate (critical thermal maximum, CT_max) and the mean or maximum environmental temperature it experiences. Yet, organisms face thermal stress and performance loss at body temperatures below their CT_max,and the steepness of that loss increases with the asymmetry of the thermal performance curve (TPC). LocationGlobal. Time period2015–2019. Major taxa studiedAnts, fish, insects, lizards and phytoplankton. MethodsWe examine variability in TPC asymmetry and the implications for thermal stress for 384 populations from 289 species across taxa and for metrics including ant and lizard locomotion, fish growth, and insect and phytoplankton fitness. ResultsWe find that the thermal optimum (T_opt, beyond which performance declines) is more labile than CT_max, inducing interspecific variation in asymmetry. Importantly, the degree of TPC asymmetry increases with T_opt. Thus, even though populations with higher T_opts in a hot environment might experience above‐optimal body temperatures less often than do populations with lower T_opts, they nonetheless experience steeper declines in performance at high body temperatures. Estimates of the annual cumulative decline in performance for temperatures above T_optsuggest that TPC asymmetry alters the onset, rate and severity of performance decrement at high body temperatures. Main conclusionsSpecies with the same TSMs can experience different thermal risk due to differences in TPC asymmetry. Metrics that incorporate additional aspects of TPC shape better capture the thermal risk of climate change than do TSMs. 

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2. Temperature Dependence of Thermal Conductivity of Proteins: Contributions of Thermal Expansion and Grüneisen Parameter

   https://doi.org/10.1002/cphc.202401017  

   Leitner, David_M (December 2024, ChemPhysChem)

   Abstract The thermal conductivity of many materials depends on temperature due to several factors, including variation of heat capacity with temperature, changes in vibrational dynamics with temperature, and change in volume with temperature. For proteins some, but not all, of these influences on the variation of thermal conductivity with temperature have been investigated in the past. In this study, we examine the influence of change in volume, and corresponding changes in vibrational dynamics, on the temperature dependence of the thermal conductivity. Using a measured value for the coefficient of thermal expansion and recently computed values for the Grüneisen parameter of proteins we find that the thermal conductivity increases with increasing temperature due to change in volume with temperature. We compare the impact of thermal expansion on the variation of the thermal conductivity with temperature found in this study with contributions of heat capacity and anharmonic coupling examined previously. Using values of thermal transport coefficients computed for proteins we also model heating of water in a protein solution following photoexcitation. 

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3. Thermal conductivity of Fe-Si alloys and thermal stratification in Earth’s core

   https://doi.org/10.1073/pnas.2119001119  

   Zhang, Youjun; Luo, Kai; Hou, Mingqiang; Driscoll, Peter; Salke, Nilesh P.; Minár, Ján; Prakapenka, Vitali B.; Greenberg, Eran; Hemley, Russell J.; Cohen, R. E.; et al (December 2021, Proceedings of the National Academy of Sciences)

   Light elements in Earth’s core play a key role in driving convection and influencing geodynamics, both of which are crucial to the geodynamo. However, the thermal transport properties of iron alloys at high-pressure and -temperature conditions remain uncertain. Here we investigate the transport properties of solid hexagonal close-packed and liquid Fe-Si alloys with 4.3 and 9.0 wt % Si at high pressure and temperature using laser-heated diamond anvil cell experiments and first-principles molecular dynamics and dynamical mean field theory calculations. In contrast to the case of Fe, Si impurity scattering gradually dominates the total scattering in Fe-Si alloys with increasing Si concentration, leading to temperature independence of the resistivity and less electron–electron contribution to the conductivity in Fe-9Si. Our results show a thermal conductivity of ∼100 to 110 W⋅m −1 ⋅K −1 for liquid Fe-9Si near the topmost outer core. If Earth’s core consists of a large amount of silicon (e.g., > 4.3 wt %) with such a high thermal conductivity, a subadiabatic heat flow across the core–mantle boundary is likely, leaving a 400- to 500-km-deep thermally stratified layer below the core–mantle boundary, and challenges proposed thermal convection in Fe-Si liquid outer core. 

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4. Evaluation of thermal properties and thermoregulatory impacts of lower back exosuit using thermal manikin

   https://doi.org/10.1016/j.ergon.2023.103517  

   Joshi, Ankit; Bartels, Lyle; Viswanathan, Shri H.; Martinez, Daniel M.; Sadeghi, Kambiz; Jaiswal, Ankush K.; Collins, Daniel; Rykaczewski, Konrad (November 2023, International Journal of Industrial Ergonomics)
5. Decoupling of temperature and thermal radiation

   https://doi.org/10.1364/NOMA.2019.NoW3B.3  

   Shahsafi, Alireza; Roney, Patrick; Zhou, You; Zhang, Zhen; Huang, Chengzi; Xiao, Yuzhe; Wan, Chenghao; Wambold, Raymond; Salman, Jad; Yu, Zhaoning; et al (January 2019, OSA Advanced Photonics Congress (IPR, Networks, NOMA, SPPCom, PVLED))

   We show that the well-known relationship between temperature and thermal radiation can be decoupled in a fully passive and reversible way using the phase transition of samarium nickelate. Our sample features temperature-independent thermally emitted power in the long-wave infrared from 90 to 120 °C, making it promising for camouflage applications. 

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