Based on the formalism of thermo-field dynamics a new approach for studying collective excitations in hot finite Fermi systems is presented. Two approximations going beyond the thermal RPA namely renormalized thermal RPA and thermal second RPA are formulated.

Dynamical models are essential for model-based control methodologies which allow smart buildings to operate autonomously in an energy and cost efficient manner. However, buildings have complex thermal dynamics which are affected externally by the environment and internally by thermal loads such as equipment and occupancy.Moreover, the physical parameters of buildingsmay change over time as the ...

In this paper, the cooling performance of water-cooled heat sinks for heat dissipation from electronic components is investigated numerically. Computational Fluid Dynamics (CFD) simulations are carried out to study the rectangular and circular cross-sectional shaped heat sinks. The sectional geometry of channels affects the flow and heat transfer characteristics of minichannel heat sinks. T...

One of the most important parameters in designing electrical motors is heat generation by the motor and the way it is dissipated. Temperature rising reduce efficiency and reliability of traction motors and leads to failure. In this paper, an urban train traction motor in a 3D computational fluid dynamics (CFD) simulation has been investigated. Maxwell software for electromagnetic simulation and...

We have been studying the heat conduction characteristics along a single-walled carbon nanotube (SWNT) by the molecular dynamics method [1-3] with the simplified form [4] of TersoffBrenner bond order potential [5]. Our preliminary results showed that thermal conductivity was strongly dependent on the nanotube length for realistic length scale for device applications [2, 3]. Furthermore, we have...

We predict the properties of the propagating and nonpropagating vibrational modes in amorphous silica (a-SiO2) and amorphous silicon (a-Si) and, from them, thermal conductivity accumulation functions. The calculations are performed using molecular dynamics simulations, lattice dynamics calculations, and theoretical models. For a-SiO2, the propagating modes contribute negligibly to thermal condu...

Quantum effects should be considered in the thermal vibrations of carbon nanotubes (CNTs). To this end, molecular dynamics based on modified Langevin dynamics, which accounts for quantum statistics by introducing a quantum heat bath, is used to simulate the thermal vibration of a cantilevered single-walled CNT (SWCNT). A nonlocal elastic Timoshenko beam model with quantum effects (TBQN), which ...

The thermal conductivity of a fluid can be significantly enhanced by dispersing nano-sized particles in it, and the resultant fluid is termed as "nanofluid". A theoretical model for estimating the thermal conductivity of a nanofluid has been proposed here. It is based on the mechanism that evenly dispersed nanoparticles within a nanofluid undergo Brownian motion in course of which the nanoparti...

In this research, an in-house code which uses the molecular dynamics method to study the flow of different nanofluids in the copper nanochannel and computes the thermo-physicals properties has been developed. The flow of nanofluids has been studied from hydro-thermally viewpoint and temperature jump at the wall has been applied. Parametric study to consider the effect of different parametric su...