Role of Random Roughness on Thermal Performance of Microfins

2007 ◽  
Vol 21 (1) ◽  
pp. 153-157 ◽  
Author(s):  
Majid Bahrami ◽  
M. Michael Yovanovich ◽  
J. Richard Culham
Keyword(s):  
Thermal Performance ◽  
Random Roughness

Role of Random Roughness on Thermal Performance of Micro-Fins

2005 ◽  
Author(s):  
M. Bahrami ◽  
M. M. Yovanovich ◽  
J. R. Culham
Keyword(s):  
Heat Transfer ◽  
Thermal Performance ◽  
Technical Conference ◽  
Electronic Systems ◽  
Cross Sectional ◽  
Random Roughness ◽  
Surface Areas ◽  
Isotropic Distribution ◽  
Developed Surface

Heat transfer in rough circular cylinder microfins is studied and a novel analytical model is developed. Surface roughness is assumed to posses a Gaussian isotropic distribution. It is shown that, as a result of roughness, both cross-sectional and surface areas are increased. As a result, an enhancement is observed in the heat transfer rate and thus the thermal performance of microfins. The present model can be implemented to analyze other geometries such as rectangular and tapered microfins.   This paper was also originally published as part of the Proceedings of the ASME 2005 Pacific Rim Technical Conference and Exhibition on Integration and Packaging of MEMS, NEMS, and Electronic Systems.

THE ROLE OF AN ELECTRICALLY HEATED FRONT COVER ON THE THERMAL PERFORMANCE OF A RADIATOR

2017 ◽  
Vol 44 (5) ◽  
pp. 409-425
Author(s):  
Francesco Corvaro ◽  
Maurizio Benucci ◽  
Barbara Marchetti ◽  
Roberta Cocci Grifoni ◽  
Fabio Polonara
Keyword(s):  
Thermal Performance ◽  
Front Cover

The role of wall layers properties on the thermal performance of ventilated facades: Experimental investigation on narrow-cavity design

2020 ◽  
Vol 209 ◽  
pp. 109622 ◽  
Author(s):  
Francesca Stazi ◽  
Giulia Ulpiani ◽  
Marianna Pergolini ◽  
Costanzo Di Perna ◽  
Marco D'Orazio
Keyword(s):  
Experimental Investigation ◽  
Thermal Performance ◽  
Cavity Design

Examining the Role of Free Carrier Concentration on the Phonon Lifetimes in GaN Using Raman Spectroscopy

2007 ◽  
Author(s):  
Thomas Beechem ◽  
Samuel Graham
Keyword(s):  
Raman Spectroscopy ◽  
Thermal Performance ◽  
Uncertainty Relation ◽  
Free Carrier ◽  
Optical Phonons ◽  
Time Uncertainty ◽  
Longitudinal Phonon ◽  
Optical Modes ◽  
Carrier Interaction

The lifetimes of polar optical phonons are known to affect the electrical and thermal performance of gallium nitride (GaN) based devices. Utilizing the energy-time uncertainty relation, this study investigates these lifetimes using Raman spectroscopy for a series of samples having free carrier concentrations ranging from 1.24e18 to 3e17 cm−3. By measuring across the typical operating temperatures of these devices, the mechanisms responsible for scattering of 5 separate optical modes are elucidated. It is found that phonon-carrier interaction directly determines the lifetime of the polar optical A1(LO) mode while indirectly influencing the modes into which this longitudinal phonon decays, namely, E1 and A1(TO). Thus understanding the entire phonon energy cascade is vital both for management of the so called “hot phonon” effect as well as modeling of carrier-phonon interactions.

scholarly journals The role of mechanistic physiology in investigating impacts of global warming on fishes

2021 ◽  
Vol 224 (Suppl 1) ◽  
pp. jeb238840
Author(s):  
Sjannie Lefevre ◽  
Tobias Wang ◽  
David J. McKenzie
Keyword(s):  
Thermal Performance ◽  
Thermal Tolerance ◽  
Specific Dynamic Action ◽  
Fish Growth ◽  
Aerobic Scope ◽  
Physiological Tolerance ◽  
Performance Curves ◽  
Supply Capacity ◽  
Underlying Mechanisms

ABSTRACTWarming of aquatic environments as a result of climate change is already having measurable impacts on fishes, manifested as changes in phenology, range shifts and reductions in body size. Understanding the physiological mechanisms underlying these seemingly universal patterns is crucial if we are to reliably predict the fate of fish populations with future warming. This includes an understanding of mechanisms for acute thermal tolerance, as extreme heatwaves may be a major driver of observed effects. The hypothesis of gill oxygen limitation (GOL) is claimed to explain asymptotic fish growth, and why some fish species are decreasing in size with warming; but its underlying assumptions conflict with established knowledge and direct mechanistic evidence is lacking. The hypothesis of oxygen- and capacity-limited thermal tolerance (OCLTT) has stimulated a wave of research into the role of oxygen supply capacity and thermal performance curves for aerobic scope, but results vary greatly between species, indicating that it is unlikely to be a universal mechanism. As thermal performance curves remain important for incorporating physiological tolerance into models, we discuss potentially fruitful alternatives to aerobic scope, notably specific dynamic action and growth rate. We consider the limitations of estimating acute thermal tolerance by a single rapid measure whose mechanism of action is not known. We emphasise the continued importance of experimental physiology, particularly in advancing our understanding of underlying mechanisms, but also the challenge of making this knowledge relevant to the more complex reality.

Numerical Modeling of the Thermal Performance of 3D SiP with TSV

2011 ◽  
Vol 189-193 ◽  
pp. 1610-1613
Author(s):  
Kai Lin Pan ◽  
Jing Huang ◽  
Jing Liu ◽  
Wei Tao Zhu ◽  
Guo Tao Ren
Keyword(s):  
Thermal Performance ◽  
Heat Dissipation ◽  
Three Dimensional ◽  
Electrical Performance ◽  
Maximum Temperature ◽  
Dimensional System ◽  
Continuous Increase ◽  
Key Technology ◽  
Three Dimensional System

Electronic package development is driven by the continuous increase in demands for miniaturization of products with enhanced performances. Three Dimensional System in Package (3D SiP) has become a key technology to satisfy the request. The 3D SiP with Through Silicon Via (TSV) technology is developed for chip to chip stacking in a package with superior electrical performance than conventional structures. In this study, we evaluate the thermal performance of 3D SiP with TSV technology using Finite Element Method (FEM). The evaluation topics covered impacts of various materials of mold, 3D SiP models with and without TSV, and various convention conditions. The results indicated that the role of TSVs in heat dissipation is not obvious in this study, and the maximum temperature merged in the center of the chip1 under different conditions which are considered.

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