scholarly journals Simulation of Discrete Blood Vessel Effects on the Thermal Signature of a Melanoma Lesion

2013 ◽  
Author(s):  
Sri Kamal Kandala ◽  
Daxiang Deng ◽  
Cila Herman
Keyword(s):  
Heat Transfer ◽  
Blood Vessel ◽  
Evaluation Criteria ◽  
Thermal Response ◽  
Skin Surface ◽  
Cancerous Lesion ◽  
Surrounding Healthy Tissue ◽  
Thermal Signature ◽  
Transient Thermal ◽  
Transient Thermal Response

The effect of the underlying blood vessel on the transient thermal response of the skin surface with and without a melanoma lesion is studied. A 3D computational model of the layers of the skin tissue with cancerous lesion was developed in COMSOL software package. Heat transfer in the skin layers and the lesion is governed by the Pennes bio-heat equation, while the blood vessel is modeled as fully developed pipe flow with constant heat transfer coefficient. The effect of various pertinent parameters, such as diameter of the blood vessel, lateral location of the blood vessel relative to the lesion, flow velocity of the blood, on the skin surface temperature distribution, have been studied in the paper. The results show significant influence of the underlying blood vessel on the temperature of the skin surface and lesion as well as on the surrounding healthy tissue. Thus, a need for development of evaluation criteria for detection of malignant lesions in the presence of blood vessels is is discussed.

A Study of Transient Heat Transfer in Long Insulated Wires

1976 ◽  
Vol 98 (1) ◽  
pp. 127-132 ◽  
Author(s):  
Y. Jaluria
Keyword(s):  
Heat Transfer ◽  
Boundary Conditions ◽  
Outer Cylinder ◽  
Thermal Response ◽  
Transient Behavior ◽  
The Body ◽  
Surface Boundary ◽  
Surface Boundary Conditions ◽  
Transient Thermal ◽  
Transient Thermal Response

This study concerns the transient thermal response of long insulated wires, a composite cylinder configuration, in which a highly conducting inner cylinder is sheathed in an outer cylinder of an insulating material. The study examines the heat transfer in such a cylindrical configuration and determines the parameters that govern its thermal response. A study of the transient behavior under various important surface boundary conditions, particularly the constant surface heat flux circumstance, is undertaken. The dependence of the transient response of the body, in terms of the characteristic surface and conductor temperatures, of the temperature distribution across the insulation and of other important physical aspects on the boundary conditions and on the governing parameters is investigated. The governing equation and boundary conditions are generalized and the solution obtained numerically to obtain the desired flexibility required for the variation in the boundary conditions. Several important and interesting results are obtained which indicate the nature of the thermal response and also the criteria for obtaining a desired variation in the transient behavior of this frequently encountered configuration.

A Parametric Study of the Transient Ablation of Teflon

1972 ◽  
Vol 94 (4) ◽  
pp. 347-354 ◽  
Author(s):  
Barry L. Clark
Keyword(s):  
Heat Transfer ◽  
Nonlinear Estimation ◽  
Thermal Response ◽  
One Dimensional ◽  
Transfer Parameters ◽  
Transient Thermal ◽  
Transient Thermal Response ◽  
Available Information ◽  
Parameter Values ◽  
Ablation Model

An analytical and experimental investigation was performed to simultaneously determine 18 ablation heat-transfer parameters for Teflon by the method of nonlinear estimation. A transient one-dimensional ablation model solved numerically was utilized to represent the thermal response of Teflon samples that were instrumented in-depth with thermocouples. The nonlinear estimation computer program was based on a modified version of Marquardt’s algorithm. A matching of the predicted and measured temperatures was effected and the results for the parameter values were in accord with available information in the literature. It was concluded that the ablation model accurately predicted the transient thermal response and surface recession of ablating Teflon.

Influence of Phonon Dispersion on Transient Thermal Response of Silicon-on-Insulator Transistors Under Self-Heating Conditions

2006 ◽  
Vol 129 (7) ◽  
pp. 790-797 ◽  
Author(s):  
Rodrigo A. Escobar ◽  
Cristina H. Amon
Keyword(s):  
Computational Models ◽  
Phonon Dispersion ◽  
Thermal Response ◽  
Domain Size ◽  
Phonon Transport ◽  
Silicon On Insulator ◽  
Nonlinear Relation ◽  
Temperature Levels ◽  
Transient Thermal ◽  
Transient Thermal Response

Lattice Boltzmann method (LBM) simulations of phonon transport are performed in one-dimensional (1D) and 2D computational models of a silicon-on-insulator transistor, in order to investigate its transient thermal response under Joule heating conditions, which cause a nonequilibrium region of high temperature known as a hotspot. Predictions from Fourier diffusion are compared to those from a gray LBM based on the Debye assumption, and from a dispersion LBM which incorporates nonlinear dispersion for all phonon branches, including explicit treatment of optical phonons without simplifying assumptions. The simulations cover the effects of hotspot size and heat pulse duration, considering a frequency-dependent heat source term. Results indicate that, for both models, a transition from a Fourier diffusion regime to a ballistic phonon transport regime occurs as the hotspot size is decreased to tens of nanometers. The transition is characterized by the appearance of boundary effects, as well as by the propagation of thermal energy in the form of multiple, superimposed phonon waves. Additionally, hotspot peak temperature levels predicted by the dispersion LBM are found to be higher than those from Fourier diffusion predictions, displaying a nonlinear relation to hotspot size, for a given, fixed, domain size.

Transient thermal response in ultrasonic additive manufacturing of aluminum 3003

2011 ◽  
Vol 17 (5) ◽  
pp. 369-379 ◽  
Author(s):  
David Schick ◽  
Sudarsanam Suresh Babu ◽  
Daniel R. Foster ◽  
Marcelo Dapino ◽  
Matt Short ◽  
...  
Keyword(s):  
Additive Manufacturing ◽  
Thermal Response ◽  
Ultrasonic Additive Manufacturing ◽  
Transient Thermal ◽  
Transient Thermal Response

Transient Thermal Response of the Media by Free Space Laser Heating in Heat Assisted Magnetic Recording

2016 ◽  
Author(s):  
Shaomin Xiong ◽  
Robert Smith ◽  
Na Wang ◽  
Dongbo Li ◽  
Erhard Schreck ◽  
...  
Keyword(s):  
Magnetic Recording ◽  
Heat Conduction Problem ◽  
Temperature Response ◽  
Thermal Response ◽  
Areal Density ◽  
Heat Assisted Magnetic Recording ◽  
Lumped Model ◽  
The Media ◽  
Transient Thermal ◽  
Transient Thermal Response

Heat assisted magnetic recording (HAMR) promises to deliver higher storage areal density than the current perpendicular magnetic recording (PMR) product. A laser is introduced to the HAMR system to heat the high coercively magnetic media above the Curie temperature (Tc) which is as high as 750 K in order to enable magnetic writing. The thermal response of the media becomes very critical for the success of the data writing process. In this paper, a new method is proposed to understand the transient thermal behavior of the HAMR media. The temperature response of the media is measured based on thermal erasure of the magnetically written signal. A lumped model is built to simplify the heat conduction problem to understand the transient thermal response. Finite element modeling (FEM) is implemented to simulate the transient thermal response of the media due to the laser pulse heating. The experimental and simulation results show fairly good agreement.

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