Laser-based phase transformation hardening (LPTH), based on rapid heating and cooling cycles produces hard and wear-resistant layers only at the selective region of the components. However, the bulk mass of the material’s core property is retained. The advantages of high power direct diode laser in comparison with other high power lasers (CO2 and Nd:YAG) have put this type of laser as a main he...

The development of high-performance thermal systems has increased interest in heat transfer enhancement techniques. The application of additives to heat transfer liquids is one of the noticeable effort to enhance heat transfer. In this paper two-dimensional unsteady incompressible nanofluid flow in a confined jet at the laminar flow regime is numerically investigated. The Mixture model is consi...

‌‌‌Fatigue behavior of a vanadium microalloy steel has been studied in this research. Here, microstructure constituents were considered which essentially are dependent on the heat treatment conditions. The results of high cycle fatigue tests revealed that heat treatment procedure and cooling rates have significant effects on fatigue properties. Optimal heat treatment cycle of the microalloyed s...

The effective parameters that influence in situ cast ferroTic composites were investigated. Centrifugal casting of specimens was carried out using ceramic & metallic molds. OM, SEM and XRD techniques were used to examine the existence of flows in the specimens. Results show that the control of chemical composition, processing, cooling rate and heat treatment has &#10a promising effect on the qu...

We formulate the work output and efficiency for linear irreversible heat engines working between a finite-sized hot heat source and an infinite-sized cold heat reservoir until the total system reaches the final thermal equilibrium state with a uniform temperature. We prove that when the heat engines operate at the maximum power under the tight-coupling condition without heat leakage the work ou...

The theory of open quantum systems is used to study the local temperature and heat currents in metallic nanowires connected to leads at different temperatures. We show that for ballistic wires the local temperature is almost uniform along the wire and Fourier’s law is invalid. By gradually increasing disorder, a uniform temperature gradient ensues inside the wire and the thermal current linearl...

We present an algorithm for solving stochastic heat equations, whose key ingredient is a non-uniform time discretization of the driving Brownian motion W . For this algorithm we derive an error bound in terms of its number of evaluations of onedimensional components of W . The rate of convergence depends on the spatial dimension of the heat equation and on the decay of the eigenfunctions of the...

We study the efficient numerical simulation of laser surface remelting, a process to improve the surface quality of steel components. To this end we use adaptive grids, which are well-suited for problems with moving heat sources. To account for the local high activity due to the heat source, we introduce local uniform grids and couple the solutions on the global coarse and local fine grids usin...

natural convection heat transfer from a vertical heated plate in a saturated porous medium is analyzed under thermal non-equilibrium assumptions. the plate is maintained at a non uniform temperature and the fluid is considered to be with internal heat generation. the coupled momentum and energy equations for fluid and solid phases are transformed to a similarity format, and solved numerically. ...