Owing to its two-dimensional electronic structure, graphene exhibits many unique properties. One of them is a wave vector and temperature dependent plasmon in the infrared range. Theory predicts that due to these plasmons, graphene can be used as a universal material to enhance nanoscale radiative heat exchange for any dielectric substrate. Here we report on radiative heat transfer experiments between SiC and a SiO2 sphere that have nonmatching phonon polariton frequencies, and thus only weakly exchange heat in near field. We observed that the heat flux contribution of graphene epitaxially grown on SiC dominates at short distances. The influence of plasmons on radiative heat transfer is further supported with measurements for doped silicon. These results highlight graphene's strong potential in photonic near field and energy conversion devices.
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http://dx.doi.org/10.1103/PhysRevLett.109.264301 | DOI Listing |
Sci Rep
January 2025
College of Engineering, Applied Science University (ASU), Manama, Kingdom of Bahrain.
This paper presents an in-depth analytical investigation into the time-dependent flow of a Casson hybrid nanofluid over a radially stretching sheet. The study introduces the effects of magnetic fields and thermal radiation, along with velocity and thermal slip, to model real-world systems for enhancing heat transfer in critical industrial applications. The hybrid nanofluid consists of three nanoparticles-Copper and Graphene Oxide-suspended in Kerosene Oil, selected for their stable and superior thermal properties.
View Article and Find Full Text PDFACS Appl Mater Interfaces
January 2025
School of Artificial Intelligence Science and Technology, University of Shanghai for Science and Technology, Shanghai 200093, China.
Passive radiative cooling has recently gained significant attention as a highly promising technology that offers a zero-energy and electricity-free solution to tackle the pressing issue of global warming. Nevertheless, research efforts have predominantly focused on enhancing daytime and hot-day radiative cooling efficacy, often neglecting the potential downsides associated with excessive cooling and the consequent increased heating expenses during cold nights and winter days. Herein, we demonstrate a micro-nanostructured engineered composite film that synergistically integrates room-temperature adaptive silica-shell/oil-core phase change microcapsules (S-PCMs) with commercially available cellulose fibers.
View Article and Find Full Text PDFACS Omega
January 2025
Key Laboratory of High Performance Ship Technology, Wuhan University of Technology, Ministry of Education, Wuhan 430063, China.
Wearable thermoelectric generator (TEG) can collect human body heat and convert it into electrical energy, achieving self-powering of the device and thus becoming a hot research topic at present. By utilization of three-dimensional spiral thin-film thermoelectric structures and passive radiation cooling methods, the heat transfer area can be increased and power generation can be enhanced. In order to study the effect of outdoor radiation cooling on the thermoelectric performance of spiral heating, as well as the TEG performance output under different external environments and circuit loads, this paper proposes a new three-dimensional coupled numerical model of the spiral thermoelectric wristband system with multiple physical fields.
View Article and Find Full Text PDFInt J Biol Macromol
January 2025
School of Chemistry and Materials Science, Hubei Engineering University, Xiaogan 43200, China.
Passive Radiant Cooling and Heating are green and sustainable methods of radiant heat management without consuming additional energy. However, the absorption of sunlight and poor insulation of materials can reduce radiative cooling and also affect radiative heating performance. Herein, we have constructed porous hierarchical dual-mode silk nanofibrous aerogel (SNF) films with high mechanical toughness and stability using silk nanofibers/GO.
View Article and Find Full Text PDFMicromachines (Basel)
January 2025
School of Mechanical Engineering and Rail Transit, Changzhou University, Changzhou 213164, China.
This study analyzes the impact of slip-dependent zeta potential on the heat transfer characteristics of nanofluids in cylindrical microchannels with consideration of thermal radiation effects. An analytical model is developed, accounting for the coupling between surface potential and interfacial slip. The linearized Poisson-Boltzmann equation, along with the momentum and energy conservation equations, is solved analytically to obtain the electrical potential field, velocity field, temperature distribution, and Nusselt number for both slip-dependent (SD) and slip-independent (SI) zeta potentials.
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