Convective transportation of materials in the solid state occurring in a prototype solid bilayer system of Al and Si with negligible mutual solubility has been directly imaged in real time at nanoscale using a valence energy-filtered transmission electron microscope. Such solid-state convection is driven by the stress gradient developing in the bilayer system due to the amorphous to crystalline phase transformation of the Si sublayer. The process is characterized by compression experienced in the Si phase crystallizing within the Al sublayer, as well as by the development of mushroom-shaped "plumes" of Al nanocrystals in the Si sublayer as a result of compressive stress relaxation and discrete, new nucleation of crystalline Al. The real-time, atomistic observation and the thus-obtained fundamental understanding of solid-state convection enable highly sophisticated applications of such a complex process in advanced fabrication and processing of nanomaterials and solid-state devices.
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http://dx.doi.org/10.1021/nl303801u | DOI Listing |
Int J Heat Mass Transf
March 2024
Department of Mechanical and Aerospace Engineering, University of California, Los Angeles, CA 90095, United States of America.
In classical theory, heat conduction in solids is regarded as a diffusion process driven by a temperature gradient, whereas fluid transport is understood as convection process involving the bulk motion of the liquid or gas. In the framework of theory, which is directly built upon quantum mechanics without relying on measured parameters or phenomenological models, we observed and investigated the fluid-like convective transport of energy carriers in solid heat conduction. Thermal transport, carried by phonons, is simulated in graphite by solving the Boltzmann transport equation using a Monte Carlo algorithm.
View Article and Find Full Text PDFSci Total Environ
December 2024
College of Emergency Management and Safety Engineering, China University of Mining and Technology (Beijing), Beijing 100083, China; Beijing Key Laboratory for Precise Mining of Intergrown Energy and Resources, China University of Mining and Technology (Beijing), Beijing 10083, China.
Slow oxidation of coal during storage and transportation poses significant risks, making it essential to identify hot spots and understand the heat generation and gas production patterns in coal stockpiles. This study leverages the advantages of adiabatic oxidation experiments, which account for time effects, to accurately describe the low-temperature oxidation process of coal through warming and gas production dimensions. Additionally, the warming and gas production patterns of three-dimensional coal stockpiles with varying stacking parameters were investigated.
View Article and Find Full Text PDFPhys Rev E
November 2024
Department of Mechanical Engineering, Indian Institute of Technology Kanpur, Uttar Pradesh 208106, India.
The hydrodynamic and thermal interactions between neighboring vapor bubbles on hot surfaces play a crucial role in heat transport and flow characteristics. To investigate these interactions, we conducted numerical simulations of saturated vapor bubbles in a two-dimensional square enclosure filled with liquid water. The water was heated at the bottom and cooled at the top to replicate boiling at 100^{∘}C and normal atmospheric pressure.
View Article and Find Full Text PDFHeliyon
May 2024
Faculty of Engineering, Kuwait College of Science and Technology, Doha District, Kuwait.
This work investigates the dynamics of the hybrid nanofluidic convective heat transfer in a permeable thermal system under the influence of multifrequency heating and a magnetic field. The geometry comprises a wavy-walled cavity filled with a water-based hybrid nanoliquid (AlO-Cu-HO) in a saturated porous medium. The finite volume approach is applied to scrutinize the hydro-thermal characteristics resulting from bottom heating and side cooling, considering various flow-controlling parameters.
View Article and Find Full Text PDFFoods
November 2024
Instituto Politécnico Nacional, CIIDIR-Unidad Oaxaca, Hornos No. 1003, Col. Noche Buena, Santa Cruz Xoxocotlán 71230, Oaxaca, Mexico.
Goat meat has a high nutritional value, since it contains up to 29% protein, as well as iron, potassium and vitamin B12. To prolong the shelf life of this food, a drying process can be applied; however, there is scarce information on the kinetics and drying parameters for this food material. The objective of this work was to characterize the thermal drying process of goat meat, through the mathematical modeling of convective drying kinetics, and its validation with experimental data obtained in a drying tunnel.
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