scholarly journals Verification of 1D numerical model for heat conduction in human tissue by means of thermography

2004 ◽  
Author(s):  
I. Boras ◽  
M. Suša ◽  
S. Švaić
Keyword(s):  
Heat Conduction ◽  
Numerical Model ◽  
Human Tissue

Heat Pulse Propagation Along Silicon Nanofilms

2012 ◽  
Author(s):  
Yanbao Ma
Keyword(s):  
Thin Film ◽  
Heat Conduction ◽  
Numerical Model ◽  
Knudsen Number ◽  
Pulse Propagation ◽  
Heat Pulse ◽  
Phonon Transport ◽  
Similarity Parameter ◽  
Ballistic Phonons ◽  
Thermal Pulses

Recent advances in nanotechnology create a demand for greater scientific understanding of the transient ballistic phonon transport at the nanoscale. It is believed that ballistic phonons may travel for long distances without destruction, but it is unclear how far they can travel. Here, a numerical model is developed to study phonon transport in silicon nanofilms. It is elucidated how thermal pulses are transmitted in silicon nanofilms by longitudinal, ballistic transverse and dispersive transverse phonons. It is found that both ballistic longitudinal and ballistic transverse phonons are highly dissipative so they can only travel for short distances, while dispersive transverse phonons at lower frequencies are less dissipative and can travel for longer distances. There exists a similarity parameter (Knudsen number) in thin-film heat conduction with different thicknesses.

New Interpretation of Non-Fourier Heat Conduction in Processed Meat

2005 ◽  
Vol 127 (2) ◽  
pp. 189-193 ◽  
Author(s):  
Paul J. Antaki
Keyword(s):  
Heat Conduction ◽  
Experimental Evidence ◽  
Human Tissue ◽  
Processed Meat ◽  
Phase Lag ◽  
Dual Phase ◽  
Hyperbolic Case ◽  
Fourier Heat Conduction ◽  
New Interpretation ◽  
Hyperbolic Conduction

This work uses the “dual phase lag” (DPL) model of heat conduction to offer a new interpretation for experimental evidence of non-Fourier conduction in processed meat that was interpreted previously with hyperbolic conduction. Specifically, the DPL model combines the wave features of hyperbolic conduction with a diffusion-like feature of the evidence not captured by the hyperbolic case. In addition, comparing the new interpretation to Fourier-based alternatives suggests that further study of all the interpretations could help advance the understanding of conduction in the processed meat and other biological materials such as human tissue.

Experimental Measurements of Temperature Distribution in Three Dimensional Stacked Package

2007 ◽  
Author(s):  
Anand Desai ◽  
James Geer ◽  
Bahgat Sammakia
Keyword(s):  
Experimental Study ◽  
Heat Conduction ◽  
Steady State ◽  
Temperature Distribution ◽  
Numerical Model ◽  
Analytical Solution ◽  
Three Dimensional ◽  
Power Input ◽  
Experimental Measurements ◽  
Steady State Heat

This paper presents the results of an experimental study of steady state heat conduction in a three dimensional stack package. The temperatures are measured at different interfaces within the stacked package. Delphi devices are used in the experiment which enables controlled power input and surface temperature of the devices. The experiment is carried out for three different boundary conditions on the package. The power input in varied to study its effects. A numerical model is created to compare to the experimental results. The results are also compared with the analytical solution presented in Desai et al [5] and Geer et al [6]. The results indicate that the experimental, numerical and analytical solutions follow the same trend. The agreement between the experimental and numerical results improves when the lateral losses are taken into account.

Proton Relaxation in a Multicompartmental System with Exchange, Simulating Human Tissue

1985 ◽  
Vol 26 (6) ◽  
pp. 745-751 ◽  
Author(s):  
A. Ericsson ◽  
A. Hemmingsson ◽  
B. Jung
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Numerical Model ◽  
Exchange Rates ◽  
Time Evolution ◽  
Human Tissue ◽  
Proton Magnetic Resonance ◽  
Proton Exchange ◽  
Proton Relaxation ◽  
Resonance Imaging

The proton magnetic resonance behaviour of human tissue was simulated with a numerical model in which the resonating nuclei were assumed to belong to five different compartments of defined relative sizes and with distinct relaxation properties. Effects of various proton exchange rates between the compartments were included in the model. The time evolution of longitudinal and transverse macroscopic magnetizations was calculated. Applications of this model in magnetic resonance imaging are discussed.

scholarly journals The Effect Of Mechanical Interactions Between The Casting And The Mold On The Conditions Of Heat Dissipation: A Numerical Model

2015 ◽  
Vol 60 (3) ◽  
pp. 1901-1910 ◽  
Author(s):  
R. Dyja ◽  
E. Gawrońska ◽  
N. Sczygiol
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Heat Conduction ◽  
Numerical Model ◽  
Computer Program ◽  
Heat Dissipation ◽  
Mechanical Interaction ◽  
The Finite Element Method ◽  
Casting Mold ◽  
Plastic Model

AbstractWe present a description of the effects of thermal interactions, which take into account formation of a shrinkage gap, that affect the level of stresses in a system casting – mold. Calculations were carried out in our own computer program which is an implementation of the finite element method used to solve the equations describing a thermo-elastic-plastic model of material and the heat conduction, including solidification. In the computing algorithm we use our own criteria for mechanical interaction between the casting and mold domains. Our model of mechanical interactions between the casting and the mold allows efficient modeling of stresses occurring in the casting and an impact of development of the shrinkage gap on cooling course.

Heat Modeling of the Catenary’s Contact Wire During the Electrical Power Supply of Trains in Station

2014 ◽  
Author(s):  
Thomas Bausseron ◽  
Philippe Baucour ◽  
Raynal Glises ◽  
Sylvain Verschelde ◽  
Didier Chamagne
Keyword(s):  
Experimental Study ◽  
Heat Flux ◽  
Heat Conduction ◽  
Heat Exchange ◽  
Numerical Model ◽  
Thermal Resistance ◽  
Power Supply ◽  
Electrical Power ◽  
Contact Wire ◽  
Interface Heat

The overheating problem of the railroad catenary at the contact with the pantograph when the train is stopped and electrically fed is responsible of many incidents. This paper describes an experimental study and a numerical model of a catenary/pantograph system used during the preconditioning of the train. Several incidents of wire breakage have highlighted the importance of the catenary/pantograph heating problem, in those incidents the contact wire had melted and broke itself. The experimental setups consists of estimating the contact’s thermal resistance and area in order to calculate which part of the interface heat flux go throught the catenary’s contact wire and which part go throught the pantograph’s collector strip. The numerical model is based on several phenomena as heat conduction into the wires, heat exchange with ambiance through convection, Joule effects and heat flux from the interface.

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