the aim of this paper is to study the kinetic study carbonylation of methanol using of the homogeneous rhodium catalyst and ch3i as the promoter in acid media based on monsanto process. the reaction was carried out in liquid media in the constant pressures 20,28 and 40 atm. and temperatures 170 to185oc, espect to the  initial  reactant concentrations and co pressure.  it was identified that the...

in the present study, an attempt has been made to synthesize 3-methyl-4-arylmethylene isoxazole-5(4h)-one derivatives through sonication of hydroxylamine hydrochloride, ethyl acetoacetate and benzaldehyde derivatives in the presence of imidazole as a novel and effective catalyst in aqueous media. this green reaction under ultrasound irradiation has advantageous compared to conventional procedur...

A theory is presented on dose calculations in inhomogeneous media that takes advantage of fast Fourier transform (FFT) convolution for practical 3-D treatment planning using photon beams. We derived a new correction dose formula which corrects the dose deposited by the Compton rst scattered photons due to the presence of inhomogeneities. We justiied theoretically why the convolution primary dos...

We propose a new method to analyze scattering light transport in homogeneous translucent media. The incident light undergoes multiple bounces in translucent media, and produces a complex light field. Our method analyzes the light transport in two steps. First, single and multiple scatterings are separated by projecting high-frequency stripe patterns. Then, the light field for each bounce scatte...

We present a variety of dissipative solitons and breathing modes in a medium with localized gain and homogeneous linear dissipation. The system possesses a number of unusual properties, like exponentially localized modes in both focusing and defocusing media, existence of modes in focusing media at negative propagation constant values, simultaneous existence of stable symmetric and antisymmetri...

The transport mechanism of contaminated groundwater has been a problematic issue for many decades, mainly due to the bad impact of the contaminants on the quality of the groundwater system. In this paper, the exact solution of two-dimensional advection-dispersion equation (ADE) is derived for a semi-infinite porous media with spatially dependent initial and uniform/flux boundary conditions. The...

The transport mechanism of contaminated groundwater has been a problematic issue for many decades, mainly due to the bad impact of the contaminants on the quality of the groundwater system. In this paper, the exact solution of two-dimensional advection-dispersion equation (ADE) is derived for a semi-infinite porous media with spatially dependent initial and uniform/flux boundary conditions. The...

As is well known, the sound-speed profile has significant effects on underwater acoustic sound propagation. These effects can be quantified by normal-mode models, for example. The basic case is a laterally homogeneous medium, for which the sound speed and the density depend on depth only and not on horizontal position. Effects of horizontal medium-parameter variation can be quantified by couple...

The relationship between velocity of chemical reactions with activities or concentrations of their reactants, temperature and pressure and the mechanisms through which the reactions proceed are of interest to many scientists and engineers. The purpose of this article is to introduce a computer software that is developed for calculation, classification and collection of such data. The applicatio...

Algorithms have been developed recently to construct realizations of random media with specified statistical correlation functions. There is a need for the formulation of exact conditions on the correlation functions in order to ensure that hypothetical correlation functions are physically realizable. Here we obtain positivity conditions on certain integrals of the autocorrelation function of d...