scholarly journals A new technique for modelling phonon scattering processes at rough interfaces and free boundaries of solids

2022 ◽  
Vol 2150 (1) ◽  
pp. 012021
Author(s):  
A A Barinov ◽  
B Liu ◽  
V I Khvesyuk
Keyword(s):  
Heat Transfer ◽  
Integrated Circuits ◽  
Phonon Scattering ◽  
Free Boundaries ◽  
Simple Method ◽  
Kapitza Conductance ◽  
Scattering Of Elastic Waves ◽  
A New Technique ◽  
Gaussian Surface ◽  
Longitudinal Thermal Conductivity

Abstract Scattering processes at interfaces and free boundaries of solids strongly affect heat transfer in micro- and nanostructures such as integrated circuits, periodic nanostructures, multilayer thin films, and other nanomaterials. Among many influencing factors, surface roughness due to atomic disorder plays a significant role in the rate of thermal transport. Existing approaches have been developed only for the limiting cases of smooth or completely diffuse surfaces. We have developed a new effective and simple method based on a direct consideration of the scattering of elastic waves from a statistically random profile (using a normal Gaussian surface as an example). This approach, first, allows to generalize common methods for determining the thermal properties of a real random rough surface using simple modifications, and, second, provides a tool for calculating the Kapitza conductance and the effective longitudinal thermal conductivity and studying the influence of roughness on heat transfer.

scholarly journals Fabrication of Eutectic Ga-In Nanowire Arrays Based on Plateau–Rayleigh Instability

Molecules ◽  
2021 ◽  
Vol 26 (15) ◽  
pp. 4616
Author(s):  
Takashi Ikuno ◽  
Zen Somei
Keyword(s):  
Integrated Circuits ◽  
Substrate Surface ◽  
Three Dimensional ◽  
Average Diameter ◽  
Nanowire Arrays ◽  
Scanning Probe ◽  
Rayleigh Instability ◽  
Simple Method ◽  
Flat Substrate ◽  
Metal Nanowire

We have developed a simple method of fabricating liquid metal nanowire (NW) arrays of eutectic GaIn (EGaIn). When an EGaIn droplet anchored on a flat substrate is pulled perpendicular to the substrate surface at room temperature, an hourglass shaped EGaIn is formed. At the neck of the shape, based on the Plateau–Rayleigh instability, the EGaIn bridge with periodically varying thicknesses is formed. Finally, the bridge is broken down by additional pulling. Then, EGaIn NW is formed at the surface of the breakpoint. In addition, EGaIn NW arrays are found to be fabricated by pulling multiple EGaIn droplets on a substrate simultaneously. The average diameter of the obtained NW was approximately 0.6 μm and the length of the NW depended on the amount of droplet anchored on the substrate. The EGaIn NWs fabricated in this study may be used for three-dimensional wiring for integrated circuits, the tips of scanning probe microscopes, and field electron emission arrays.

A Computational Study of the Interaction of Melting Soil With Moisture Transport in the Native Soil

1998 ◽  
Author(s):  
Will Schreiber ◽  
John Kuo
Keyword(s):  
Heat Transfer ◽  
Heat Flow ◽  
Moisture Transport ◽  
Moving Boundary ◽  
Computational Study ◽  
Fluid Motion ◽  
Computer Code ◽  
General Purpose ◽  
Simple Method ◽  
Porous Soil

Abstract The current paper describes a computer model designed to analyze the moisture transport in the unmelted, porous soil neighboring a convecting melt. The time-dependent fluid and heat flow in the soil melt is simulated implicitly using the SIMPLE method generalized to predict viscous fluid motion and heat transfer on boundary-fitted, non-orthogonal coordinates which adapt with time. TOUGH2, a general-purpose computer code for multiphase fluid and heat flow developed by K. Pruess at Lawrence Berkekey Laboratory, has been modified for use on time-adaptive, boundary-fitted coordinates to predict heat transfer, moisture and air transport, and pressure distribution in the porous, unmelted soil. The soil melt model is coupled with the modified TOUGH2 model via an interface (moving boundary) whose shape is determined implicitly with the progression of time. The computer model’s utility is demonstrated in the present study with a special two-dimensional study. A soil initially at 20°C and partially-saturated with either a 0.2 or 0.5 relative liquid saturation is contained in a box two meters wide by ten meters high with impermeable bottom and sides. The upper surface of the soil is exposed to a 20°C atmosphere to which vapor and air can escape. Computation begins when the soil, which melts at 1700°C, is heated from one side (maintained at constant temperatures ranging from 1700°C to 4000°C). Heat from the hot wall causes the melt to circulate in such a way that the melt interface grows more rapidly at the top of the box than at the bottom. As the upper portion of the melt approaches the impermeable wall it creates a bottle neck for moisture release from the soil’s lower regions. The pressure history of the trapped moisture is examined as a means for predicting the potential for moisture penetration into the melt. The melt’s interface movement and moisture transport in the unmelted, porous soil are also examined.

scholarly journals Statistical model of phonon scattering on rough boundaries of nanostructures

2021 ◽  
Vol 2057 (1) ◽  
pp. 012111
Author(s):  
A A Barinov ◽  
V I Khvesyuk
Keyword(s):  
Heat Transfer ◽  
Statistical Model ◽  
Phonon Scattering ◽  
Rapid Development ◽  
Decisive Role ◽  
Comprehensive Analysis ◽  
Urgent Task ◽  
Semiconductor Electronics ◽  
Ballistic Heat Transfer ◽  
Rough Boundaries

Abstract Because of the rapid development of semiconductor electronics and the tendency to size reduction of the elements of transistors, there is an urgent task of assessing the heat transfer regime, which determines the ability to maintain the required thermal regime. In this work, the heat transfer in micro- and nanostructures in silicon is considered, and a comprehensive analysis of factors determining the heat transfer regime is carried out. In particular, the effect of the interaction of phonons with the sample boundaries in the quasi-ballistic and ballistic heat transfer regimes, where these processes play a decisive role, is evaluated using statistical model of phonon scattering on rough boundaries of samples.

scholarly journals A new technique for the efficient use of Macro-Mistnets

Koedoe ◽  
1985 ◽  
Vol 28 (1) ◽  
Author(s):  
I.L. Rautenbach
Keyword(s):  
New Technique ◽  
Simple Method ◽  
A New Technique

A cheap and simple method of adapting yacht masts to allow quick and efficient stringing and versatile manipulation of a 6,0 x 30,0 metre macro-mistnet, is described.

Simple Model of Boiling Heat Transfer on Tubes in Large Pools

1997 ◽  
Vol 119 (2) ◽  
pp. 376-379 ◽  
Author(s):  
Y. Parlatan ◽  
U. S. Rohatgi
Keyword(s):  
Heat Transfer ◽  
Experimental Data ◽  
Heat Flux ◽  
Heat Exchanger ◽  
Atmospheric Pressure ◽  
Boiling Heat Transfer ◽  
Saturation Temperature ◽  
Flow Dynamics ◽  
Simple Method ◽  
Vertical Tubes

A simple method has been developed to model boiling heat transfer from a heat exchanger to pools using the experimental data available in the literature without modeling the flow dynamics of the pool. In this approach the heat flux outside vertical tubes is expressed as a function of outside wall temperature of the tubes and saturation temperature of the pool at or near atmospheric pressure.

Specific features of heat transfer in the orientationally ordered phases of molecular crystals in the region with predominant phonon-phonon scattering

2015 ◽  
Vol 41 (7) ◽  
pp. 551-556 ◽  
Author(s):  
A. I. Krivchikov ◽  
O. O. Romantsova ◽  
O. A. Korolyuk ◽  
G. A. Vdovichenko ◽  
Yu. V. Horbatenko
Keyword(s):  
Heat Transfer ◽  
Phonon Scattering ◽  
Molecular Crystals ◽  
Ordered Phases

MC Simulation of Radiative Heat Transfer Between Planar Semi-Infinite Media and Nano-Spheres With Near Field Effect

2004 ◽  
Author(s):  
Yong Huang ◽  
Xin-Gang Liang
Keyword(s):  
Heat Transfer ◽  
Radiative Heat Transfer ◽  
Field Effect ◽  
Radiative Heat ◽  
Near Field ◽  
Emissive Power ◽  
Simple Method ◽  
The Difference ◽  
Near Field Effect ◽  
Infinite Media

Based on the principle of electric dipole radiation and the Planck’s spectral distribution of emissive power, the enhancement of thermal radiation between two planar semi-infinite media or two nano-spheres was studied in this paper by the Monte Carlo method. By this simple method, some parameter’s influence on the radiative heat transfer was investigated, such as the distance between two semi-infinite media, the particle’s radius, the distance between two particles and the difference in temperature between two particles, and so on. This solution is not rigorous but simple. The results show that heat transfer can be enhanced by several orders of magnitude for the near field effect. And the radiative heat transfer is decreasing sharply with the increasing of the distance.

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