We have experimentally investigated the heat transfer mechanisms at a 90610 nm diameter point contact between a sample and a probe tip of a scanning thermal microscope (SThM). For large heated regions on the sample, air conduction is the dominant tipsample heat transfer mechanism. For micro/nano devices with a submicron localized heated region, the air conduction contribution decreases, whereas...

The thermal performance of a heat exchanger is important for the potential application in an integrated solar cell/module and thermoelectric generator (TEG) system. Usually, the thermal performance of a heat exchanger for TEGs is analysed by using 1D heat conduction theory which ignores the detailed phenomena associated with thermo-hydraulics. In this paper, thermal and momentum transports in t...

Irreversibility (that is, the “one-sidedness” of time) of a physical process can be characterized by using Lyapunov functions in the modern theory of stability. In this theoretical framework, entropy and its production rate have been generally regarded as Lyapunov functions in order to measure the irreversibility of various physical processes. In fact, the Lyapunov function is not always unique...

1 B. Terry Beck, Kansas State University, Mechanical and Nuclear Engineering Department, 302 Rathbone Hall, Manhattan, KS 66506 [email protected] Abstract  The main objective of this paper is to present two different experiments that have been developed to successfully demonstrate transient heat conduction phenomena. The first experiment illustrates the approximate measurement of transient local h...

The diffusive-ballistic heat conduction of finite-length single-walled carbon nanotubes has been studied by means of nonequilibrium molecular dynamics simulations. The length dependence of thermal conductivity [1] is quantified for a range of nanotube lengths up to 1.6 μm at room temperature. A gradual transition from nearly pure ballistic to diffusive-ballistic heat conduction was identified f...

This paper considers a linear one dimensional inverse heat conduction problem with non constant thermal diffusivity and two unknown terms in a heated bar with unit length. By using the WKB method, the heat flux at the end of boundary and initial temperature will be approximated, numerically. By choosing a suitable parameter in WKB method the ill-posedness of solution will be improved. Finally, ...

To realize the lagging behavior in heat conduction observed in these two decades, this paper firstly theoretically excludes the possibility that the underlying thermal inertia is a result of the time delay in heat diffusion. Instead, we verify in experiments the electro-thermal analogy, wherein the thermal inertial is parameterized by thermal inductance that formulates hyperbolic heat-conductio...

We study the heat conduction of a cold, thermal cloud in a highly asymmetric trap. The cloud is axially hydrodynamic, but due to the asymmetric trap radially collisionless. By locally heating the cloud we excite a thermal dipole mode and measure its oscillation frequency and damping rate. We find an unexpectedly large heat conduction compared to the homogeneous case. The enhanced heat conductio...

Temperature distributions recorded by thermocouples in a solid body (slab) subject to surface heating are used in a mathematical model of 2-D heat conduction. The corresponding Dirichlet problem for a holomorphic function (complex potential), involving temperature and heat stream function, is solved in a strip. The Zhukovskii function is reconstructed through singular integrals, involving an au...

Background/introduction Thermal ablation techniques using heat conduction (e.g. radiofrequency ablation) are sensitive to the cooling effect of blood flow, the heat sink effect. Thermal ablation by high intensity ultrasound guided by magnetic resonance imaging (MRgHIFU), is less dependent on heat conduction, and produces sharply delineated ablated volumes. The aim of this study was to ablate ad...