We derive the conditions for establishment of a transverse supermode in a free-electron laser ~FEL! oscillator, and demonstrate the evolution of a supermode by means of a three-dimensional nonlinear code. Both the analytical formulation and the numerical code are based on coupled-mode theory. The oscillator supermode is a combination of transverse modes that keeps its field profile at any point...

We study the steady state of a finite XX chain coupled at its boundaries to quantum reservoirs made of free spins that interact one after the other with the chain. The two-point correlations are calculated exactly, and it is shown that the steady state is completely characterized by the magnetization profile and the associated current. Except at the boundary sites, the magnetization is given by...

high weissenberg boundary layer flow of viscoelastic fluids on a stretching surface has been studied. the flow is considered to be steady and two dimensional. flows of viscoelastic liquids at high weissenberg number exhibit stress boundary layers near walls. these boundary layers are caused by the memory of the fluid. upon proper scaling and by means of an exact similarity transformation, the n...

A number of exact results have been obtained recently for the one-dimensional asymmetric simple exclusion process, a model of particles which hop to their right at random times, on a one-dimensional lattice, provided that the target site is empty. Using either a matrix form for the steady-state weights or the Bethe ansatz, several steady-state properties can be calculated exactly: the current, ...

Subcooled flow boiling in multi-microchannels can be used as an efficient thermal management approach in compact electrical devices. Highly subcooled flow boiling of HFE 7100 is studied in two microchannel heat sinks to choose a proper numerical model for simulating boiling flows in microchannels. Results of five different numerical models, including Volume of Fluid (VOF), Eulerian boiling, Eul...

Due to the continuous increment of the load demand, identification of weaker buses, improvement of voltage profile and power losses in the context of the voltage stability problems has become one of the major concerns for the larger, complex, interconnected power systems. If the voltage profile of the weaker buses is improved, the voltage stability can be improved significantly. Because of the ...

Characteristics of electromagnetic wave propagation through a magnetized plasma slab with linear electron density profile is analysed. In the numerical analysis, cold, weakly ionized, collisional and steady state plasma layer is divided into sufficiently thin, adjacent subslabs, in each of which plasma parameters are constant. Reflection and transmission coefficients are calculated for discreti...

This study employed grain dynamic models to examine the density distribution of debris discs, and discussed the effects of the collisional time-intervals of asteroidal bodies, the maximum grain sizes, and the chemical compositions of the dust grains of the models, in order to find out whether a steady out-moving flow with an 1/R profile could be formed. The results showed that a model with new ...

Mixed matrix membranes (MMMs) are attracting significant interest for pervaporation and gas separation applications. To better comprehend the impact of filler particles within polymer matrices, the species permeation mass transport was theoretically studied by numerical simulation using finite differences. The Fick’s second law of diffusion was solved for a three-dimensional MMM to obtain the c...

This paper presents a comprehensive and exclusive thermodynamic analysis of counter flow heat exchanger under various operating and geometrical conditions. Analysis system (ANSYS) workbench 14.0 has been used for computational analysis and comparison with previous literature has been carried out in view of variable temperature and mass flow rate of hot and cold fluids. An analytical and statist...