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1. Thermal Transport in 2D Materials

   https://doi.org/10.3390/nano13010117  

   Kalantari, Mohammad Hassan; Zhang, Xian (January 2023, Nanomaterials)

   In recent decades, two-dimensional materials (2D) such as graphene, black and blue phosphorenes, transition metal dichalcogenides (e.g., WS2 and MoS2), and h-BN have received illustrious consideration due to their promising properties. Increasingly, nanomaterial thermal properties have become a topic of research. Since nanodevices have to constantly be further miniaturized, thermal dissipation at the nanoscale has become one of the key issues in the nanotechnology field. Different techniques have been developed to measure the thermal conductivity of nanomaterials. A brief review of 2D material developments, thermal conductivity concepts, simulation methods, and recent research in heat conduction measurements is presented. Finally, recent research progress is summarized in this article. 

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2. Thermal exploration in engine design

   https://doi.org/10.1126/science.adg7317  

   Carr, Lincoln D; Parigi, Valentina (March 2023, Science)

   A negative-temperature heat engine is achieved with photons 

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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. Thermal Conductivity Determination of Ga-In Alloys for Thermal Interface Materials Design

   https://doi.org/10.3390/thermo2010001  

   Maivald, Parker; Sridar, Soumya; Xiong, Wei (March 2022, Thermo)

   Thermal interface material (TIM) that exists in a liquid state at the service temperature enables efficient heat transfer across two adjacent surfaces in electronic applications. In this work, the thermal conductivities of different phase regions in the Ga-In system at various compositions and temperatures are measured for the first time. A modified comparative cut bar technique is used for the measurement of the thermal conductivities of GaxIn1−x (x = 0, 0.1, 0.214, 0.3, and 0.9) alloys at 40, 60, 80, and 100 °C, the temperatures commonly encountered in consumer electronics. The thermal conductivity of liquid and semi-liquid (liquid + β) Ga-In alloys are higher than most of the TIM’s currently used in consumer electronics. These measured quantities, along with the available experimental data from literature, served as input for the thermal conductivity parameter optimization using the CALPHAD (calculation of phase diagrams) method for pure elements, solution phase, and two-phase region. A set of self-consistent parameters for the description of the thermal conductivity of the Ga-In system is obtained. There is good agreement between the measured and calculated thermal conductivities for all of the phases. Due to their ease of manufacturing and high thermal conductivity, liquid/semi-liquid Ga-In alloys have significant potential for TIM in consumer electronics. 

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5. Late Lutetian Thermal Maximum-Crossing a Thermal Threshold in Earth's Climate System?

   https://doi.org/10.1002/2017GC007240  

   Westerhold, T.; Röhl, U.; Donner, B.; Frederichs, T.; Kordesch, W. E.; Bohaty, S. M.; Hodell, D. A.; Laskar, J.; Zeebe, R. E. (January 2018, Geochemistry, Geophysics, Geosystems)