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Title: Suppressing thermal transport in nonporous polymer hybrids by limiting thermally accessible vibrational modes
Low thermal conductivity in nonporous polymer hybrids is enabled by limiting thermally accessible vibrational modes, without relying on porosity or individual interfacial thermal resistance. more »« less
Hona, Ram Krishna
(, Academic Journal of Polymer Science)
unknown
(Ed.)
The thermal conductivity of CaSrFe2O6-δ, an oxygen-deficient perovskite, is a critical parameter for understanding its thermal transport properties and potential applications in energy conversion and electronic devices. In this study, we present an investigation of the thermal conductivity of CaSrFe2O6-δ at room temperature for its thermal insulation property study. Experimental measurement was conducted using a state-of-the-art thermal characterization technique, Thermtest thermal conductivity meter. The thermal conductivity of CaSrFe2O6-δ was found to be 0.574W/m/K, exhibiting a notable thermal insulation property.
Bogan, Samuel N; Porat, Olivia I; Meneses, Michael J; Hofmann, Gretchen E
(, Functional Ecology)
Abstract Under climate change, ectotherms will likely face pressure to adapt to novel thermal environments by increasing their upper thermal tolerance and its plasticity, a measure of thermal acclimation. Ectotherm populations with high thermal tolerance are often less thermally plastic, a trade‐off hypothesized to result from (i) a phenotypic limit on thermal tolerance above which plasticity cannot further increase the trait, (ii) negative genetic correlation or (iii) fitness trade‐offs between the two traits. Whether each hypothesis causes negative associations between thermal tolerance and plasticity has implications for the evolution of each trait.We empirically tested the limit and trade‐off hypotheses by leveraging the experimental tractability and thermal biology of the intertidal copepodTigriopus californicus. Using populations from four latitudinally distributed sites in coastal California, six lines per population were reared under a laboratory common garden for two generations. Ninety‐six full sibling replicates (n = 4–5 per line) from a third generation were developmentally conditioned to 21.5 and 16.5°C until adulthood. We then measured the upper thermal tolerance and fecundity of sibships at each temperature.We detected a significant trade‐off in fecundity, a fitness corollary, between baseline thermal tolerance and its plasticity.Tigriopus californicuspopulations and genotypes with higher thermal tolerance were less thermally plastic. We detected negative directional selection on thermal plasticity under ambient temperature evidenced by reduced fecundity. These fitness costs of plasticity were significantly higher among thermally tolerant genotypes, consistent with the trade‐off hypothesis. This trade‐off was evident under ambient conditions, but not high temperature.Observed thermal plasticity and fecundity were best explained by a model incorporating both the limit and trade‐off hypotheses rather than models with parameters associated with one hypothesis. Effects of population and family on tolerance and plasticity negatively covaried, suggesting that a negative genetic correlation could not be ruled as contributing to negative associations between the traits. Our study provides a novel empirical test of the fitness trade‐off hypothesis that leverages a strong inference approach. We discuss our results' insights into how thermal adaptation may be constrained by physiological limits, genetic correlations, and fitness trade‐offs between thermal tolerance and its plasticity. Read the freePlain Language Summaryfor this article on the Journal blog.
Medicine_Cloud, Gillian; Guinn, Mandy; Krishna_Hona, Ram
(, New Energy Exploitation and Application)
CaSrFe0.75Co0.75Mn0.5O6-δ, an oxygen-deficient perovskite, had been reported for its better electrocatalytic properties of oxygen evolution reaction. It is essential to investigate different properties such as the thermal conductivity of such efficient functional materials. The thermal conductivity of CaSrFe0.75Co0.75Mn0.5O6-δ is a critical parameter for understanding its thermal transport properties and potential applications in energy conversion and electronic devices. In this study, the authors present an investigation of the thermal conductivity of CaSrFe0.75Co0.75Mn0.5O6-δ at room temperature for its thermal insulation property study. Experimental measurement was conducted using a state-of-the-art thermal characterization technique, Thermtest thermal conductivity meter. The thermal conductivity of CaSrFe0.75Co0.75Mn0.5O6-δ was found to be 0.724 W/m/K at 25 °C, exhibiting a notable thermal insulation property i.e., low thermal conductivity.
Rafique, Muhammad Shahbaz; Ridoy, Asif Hasan; Haque, A_K_M Abirul; Farfan, Marcelo; Ashraf, Ali; Kumar, Ashok
(, American Society of Mechanical Engineers)
Abstract Carbon Nanofibers and fiber mats with thermal management properties are gaining attention for applications like energy storage, thermal insulation, and comfort. Optimal performance requires these materials to be lightweight, cost-effective, and have high thermal conductivity. Nanodiamonds, with their exceptional mechanical, electrical, thermal, and optical qualities, are promising enhancers for thermal management in electronics. They improve device performance significantly when applied to carbon nanofibers and mats. However, traditional nanodiamond deposition methods, such as spin and dip coating, often face challenges through poor uniformity, material waste, and fiber damage. To address this, we utilized an electrostatic corona discharge method, an innovative and efficient bottom-up approach that avoids contamination and enhances the thermal and mechanical properties of fibers through the elimination of polymer binders. This method creates an ionized field to attach nanodiamond particles evenly to fiber surfaces. Characterization techniques, including VHX microscope, Raman spectroscopy, and thermal conductivity tests, confirmed significant improvements in carbon nanofiber mats performance where the thermal conductivity was increased by approximately 85.7% upon coating with nanodiamonds. These enhanced materials surpass conventional polymer-based solutions, offering improved thermal conductivity due to optimized nanodiamond size, voltage application, and uniformity. They show promise as multifunctional nanocomposites for applications like flexible electronics, thermal management, and intelligent wearables.
Couper, Lisa I; Farner, Johannah E; Lyberger, Kelsey P; Lee, Alexandra S; Mordecai, Erin A
(, Proceedings of the Royal Society B: Biological Sciences)
How mosquitoes may respond to rapid climate warming remains unknown for most species, but will have major consequences for their future distributions, with cascading impacts on human well-being, biodiversity and ecosystem function. We investigated the adaptive potential of a wide-ranging mosquito species,Aedes sierrensis, across a large climatic gradient by conducting a common garden experiment measuring the thermal limits of mosquito life-history traits. Although field-collected populations originated from vastly different thermal environments that spanned over 1200 km, we found limited variation in upper thermal tolerance between populations. In particular, the upper thermal limits of all life-history traits varied by less than 3°C across the species range and, for most traits, did not differ significantly between populations. For one life-history trait—pupal development rate—we did detect significant variation in upper thermal limits between populations, and this variation was strongly correlated with source temperatures, providing evidence of local thermal adaptation for pupal development. However, we found that maximum environmental temperatures across most of the species' range already regularly exceed the highest upper thermal limits estimated under constant temperatures. This result suggests that strategies for coping with and/or avoiding thermal extremes are likely key components of current and future mosquito thermal tolerance.
@article{osti_10692058,
place = {Country unknown/Code not available},
title = {Suppressing thermal transport in nonporous polymer hybrids by limiting thermally accessible vibrational modes},
url = {https://par.nsf.gov/biblio/10692058},
DOI = {10.1039/D6MH00633G},
abstractNote = {Low thermal conductivity in nonporous polymer hybrids is enabled by limiting thermally accessible vibrational modes, without relying on porosity or individual interfacial thermal resistance.},
journal = {Materials Horizons},
publisher = {Materials Horizons},
author = {Worden, Henry and Chandra, Mihir and Zhou, Yijie and Bhuiyan, Zarif_Ahmad Razin and Cheng, Mouyang and Munusamy, Krishnamurthy and Nghiem, Duc and Hu, Weiguo and Yan, Weibo and Wu, Siyu and Li, Ruipeng and Jiang, Zhang and Chatterji, Anna and Zhang, Shengjia and Ivanov, Ilia N and Chen, Jihua and Lasseter, Jack C and Jin, Mengru and Abitagaoglu, Derin and Tu, Qing and Emrick, Todd and Liu, Jun and Xu, Yanfei},
}
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