We study the process of thermal convection in jammed emulsions with a yield-stress rheology. We find that heat transfer occurs via an intermittent mechanism, whereby intense short-lived convective "heat bursts" are spaced out by long-lasting conductive periods. This behavior is the result of a sequence of fluidization-rigidity transitions, rooted in a nontrivial interplay between emulsion yield-stress rheology and plastic activity, which we characterize via a statistical analysis of the dynamics at the droplet scale. We also show that droplets' coalescence induced during heat bursts leads to a spatially heterogeneous phase inversion of the emulsion which eventually supports a sustained convective state.
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http://dx.doi.org/10.1103/PhysRevLett.133.244001 | DOI Listing |
Phys Rev Lett
December 2024
Department of Physics and INFN, Tor Vergata University of Rome, Via della Ricerca Scientifica 1, 00133 Rome, Italy.
We study the process of thermal convection in jammed emulsions with a yield-stress rheology. We find that heat transfer occurs via an intermittent mechanism, whereby intense short-lived convective "heat bursts" are spaced out by long-lasting conductive periods. This behavior is the result of a sequence of fluidization-rigidity transitions, rooted in a nontrivial interplay between emulsion yield-stress rheology and plastic activity, which we characterize via a statistical analysis of the dynamics at the droplet scale.
View Article and Find Full Text PDFSci Adv
January 2025
State Key Laboratory of Lithospheric and Environmental Coevolution, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029, China.
The evolution of the lunar magnetic field can reveal the Moon's interior structure, thermal history, and surface environment. The mid-to-late-stage evolution of the lunar magnetic field is poorly constrained, and thus, the existence of a long-lived lunar dynamo remains controversial. The Chang'e-5 mission returned the heretofore youngest mare basalts from Oceanus Procellarum uniquely positioned at midlatitude.
View Article and Find Full Text PDF3D Print Addit Manuf
October 2024
Department of Aircraft Manufacturing Engineering, School of Aerospace Engineering, Guizhou Institute of Technology, Guiyang, China.
The application of a pulsed magnetic field (PMF) during a metallurgy solidification process has proven to be an effective method in refining the grain size and improving the mechanical performance of the material. However, fewer works were reported in the realm of laser additive manufacturing (LAM) and the mechanism of grain refinement consequent to the PMF is still unclear. In this work, numerical models were developed to study the thermal-fluid characteristics in the Ti-alloy melt pool generated during the laser scanning process under the effect of a combined direct current (DC) electric field and PMF.
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December 2024
Department of Physics, Laghman University, Mehtarlam City, Laghman, 2701, Afghanistan.
Aluminum alloys have promising characteristics which make them more useful in industrial applications for thermal management and entropy of the fluidic system. Hence, the current research deals with the analysis of entropy and thermal performance of (CHO-HO)/50:50% saturated by (AA7072/AA7076/TiAIV) alloys. Traditional problem modified using enhanced characteristics of ternary alloys and hydrocarbon 50:50% base fluid.
View Article and Find Full Text PDFInt 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.
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