Deformation of the quintom cosmological model and its consequences

In this paper, we investigate the effects of non-commutative phase-space on the quintom cosmological model. In that case, we discuss $\Lambda_{1}$, $\Lambda_{2}$ and other cosmological parameters and show that they are associated to deformation parameters $\theta$ and $\beta$. Generally one can say that, the non-commutative parameter plays important role in physics and here also help us to arrange the divergency of cosmological constant. We draw time-dependent scale factor and investigate the effect of non-commutative parameters. Finally, we take advantage from non-commutative phase-space and obtain the deformed Lagrangian for the quintom model. In order to discuss some cosmological phenomena as dark energy and inflation, we employ Neother symmetry.Comment: 17 pages, 1 figure. References added in the revised versio

Half-optical-cycle damped solitons in quadratic nonlinear media

In this paper, Using a classical model of the radiation-matter interaction, we show that the propagation of (1 + 1) dimensional few-optical-cycle pulses in quadratic nonlinear media, taking moderate absorption into account, can be described by the Korteweg–de Vries-Burgers’ (KdVB) equation without using the slowly varying envelope approximation. To fulfill this purpose we use the reductive perturbation method and consider the long-wave approximation, assuming that the characteristic frequency of the pulse is much lower than the resonance frequency of the atoms. We also study both analytical and numerical solution of the KdVB equation describing damped few-optical-cycle soliton propagation

Optical Emission Spectroscopy and Electrical Study of High Power Thermal Arc Plasma Switching Device

In this work, an atmospheric thermal plasma arc generated from a laboratory scale high power arc switching device was investigated. In the presented study the typical voltage and current profiles from the arc switching device were measured by a high voltage probe and a Rogowski coil. It was shown that the volt-ampere characteristic of the arc plasma is directly related to the distance between electrodes. This switching device has a pulse width range of approximately 120 ns. Furthermore, the optical emis-sion spectroscopy techniques were used to measurement of the arc temperature and to identify the plasma active species. The calculated arc temperature is about 14000 K

A Novel Analytical Solution to Steady-State Evaporation from Soil and Film Region Thickness

Evaporation from soil and other porous media constitutes a significant source of water loss affecting global water balance and energy exchange between land and atmosphere. The presence of a shallow water table can lead to sustained water loss that is dependent on porous media hydraulic properties and water table depth among other factors. In this paper, an exact analytical solution to steady state evaporation from porous media is developed using the Brooks-Corey hydraulic conductivity model. The solution is presented in terms of a set of infinite series. An advantage of this solution compared to previous derivations is that the infinite series can be very closely approximated using a closed-form solution (i.e., excluding integrals or series). The novel solution shows excellent agreement with the exact solution for a broad range of soil texture from sand to clay. The applicability of the solution to predict the location of the drying front was also verified using experimental data taken from the literature. The solution may be used for directly modeling steady state evaporation or for inverse determination of the Brooks-Corey hydraulic parameters

Reproductive biology of blue swimming crab, Portunus segnis (Forskal, 1775) in coastal waters of Persian Gulf and Oman Sea, Iran

A reproductive biology study of blue swimming crab, Portunus segnis (Forskal, 1775) in the northern Persian Gulf and Oman Sea, was conducted from May 2010 to October 2011. The results showed that the annual sex ratio is not M:F=1:1, with 51.9 % female. All the five stages of ovarian development of P. segnis were observed throughout the year. The size of ovigerous crabs varied from 103 to 155 mm carapace width. This crab can spawn all year round with a spawning peak in mid-winter to early of spring season. The fecundity of ovigerous crabs ranged from 521027 to 6656599 eggs, with average fecundity of 2397967 eggs. The minimum carapace width (CW) of female crabs that reach sexual maturity was 92-138 mm and the length at which 50% of all ovigerous females was 113 mm carapace width

Nuclear classical dynamics of H2_2 in intense laser field

In the first part of this paper, the different distinguishable pathways and regions of the single and sequential double ionization are determined and discussed. It is shown that there are two distinguishable pathways for the single ionization and four distinct pathways for the sequential double ionization. It is also shown that there are two and three different regions of space which are related to the single and double ionization respectively. In the second part of the paper, the time dependent Schr\"{o}dinger and Newton equations are solved simultaneously for the electrons and the nuclei of H$_2$ respectively. The electrons and nuclei dynamics are separated on the base of the adiabatic approximation. The soft-core potential is used to model the electrostatic interaction between the electrons and the nuclei. A variety of wavelengths (390 nm, 532 nm and 780 nm) and intensities ($5\times10^{14}$ $Wcm^{-2}$ and $5\times10^{15}$ $Wcm^{-2}$) of the ultrashort intense laser pulses with a sinus second order envelope function are used. The behaviour of the time dependent classical nuclear dynamics in the absence and present of the laser field are investigated and compared. In the absence of the laser field, there are three distinct sections for the nuclear dynamics on the electronic ground state energy curve. The bond hardening phenomenon does not appear in this classical nuclear dynamics simulation.Comment: 16 pages, 7 figure

The effects of a magnetic barrier and a nonmagnetic spacer in tunnel structures

The spin-polarized transport is investigated in a new type of magnetic tunnel junction which consists of two ferromagnetic electrodes separated by a magnetic barrier and a nonmagnetic metallic spacer. Based on the transfer matrix method and the nearly-free-electron-approximation the dependence of the tunnel magnetoresistance (TMR) and electron-spin polarization on the nonmagnetic layer thickness and the applied bias voltage are studied theoretically. The TMR and spin polarization show an oscillatory behavior as a function of the spacer thickness and the bias voltage. The oscillations originate from the quantum well states in the spacer, while the existence of the magnetic barrier gives rise to a strong spin polarization and high values of the TMR. Our results may be useful for the development of spin electronic devices based on coherent transport.Comment: 15 pages, 5 figure