M. Z. M. Kamali

Positron scattering from hydrogen atom embedded in dense quantum plasma

Scattering of positrons from the ground state of hydrogen atoms embedded in dense quantum plasma has been investigated by applying a formulation of the three-body collision problem in the form of coupled multi-channel two-body Lippmann-Schwinger equations. The interactions among the charged particles in dense quantum plasma have been represented by exponential cosine-screened Coulomb potentials. Variationally determined hydrogenic wave function has been employed to calculate the partial-wave scattering amplitude. Plasma screening effects on various possible mode of fragmentation of the system e++H(1s) during the collision, such as 1s→1s and 2s→2s elastic collisions, 1s→2s excitation, positronium formation, elastic proton-positronium collisions, have been reported in the energy range 13.6-350 eV. Furthermore, a comparison has been made on the plasma screening effect of a dense quantum plasma with that of a weakly coupled plasma for which the plasma screening effect has been represented by the Debye model. ...

Positron scattering from hydrogen atom embedded in weakly coupled plasma

The positron-hydrogen collision problem in weakly coupled plasma environment has been investigated by applying a formulation of the three-body collision problem in the form of coupled multi-channel two-body Lippmann-Schwinger equations. The interactions among the charged particles in the plasma have been represented by Debye-Huckel potentials. A simple variational hydrogenic wave function has been employed to calculate the partial-wave scattering amplitude. Plasma screening effects on various possible mode of fragmentation of the system e++H(1s) during the collision, such as 1s→1s and 2s→2s elastic collisions, 1s→2s excitation, positronium formation, elastic proton-positronium collisions, have been reported. Furthermore, a detailed study has been made on differential and total cross sections of the above processes in the energy range 13.6-350 eV of the incident positron.

Charge transfer in proton-hydrogen collisions under Debye plasma

The effect of plasma environment on the 1s → nlm charge transfer, for arbitrary n, l, and m, in proton-hydrogen collisions has been investigated within the framework of a distorted wave approximation. The effect of external plasma has been incorporated using Debye screening model of the interacting charge particles. Making use of a simple variationally determined hydrogenic wave function, it has been possible to obtain the scattering amplitude in closed form. A detailed study has been made to investigate the effect of external plasma environment on the differential and total cross sections for electron capture into different angular momentum states for the incident energy in the range of 20–1000 keV. For the unscreened case, our results are in close agreement with some of the most accurate results available in the literature.

Positron scattering from hydrogen atom with screened Coulomb potentials

Elastic positron-hydrogen collisions with screened Coulomb potentials have been investigated using a second-order distorted wave Born approximation in the momentum space. Two types of potentials have been considered, namely, static screened Coulomb potential and exponential cosine-screened Coulomb potential. Using a simple variationally determined hydrogenic wave function it has been possible to obtain the scattering amplitude in a closed form. A detailed study has been made on the differential and total cross sections in the energy range 20–300 eV.

A neuro approach to solve fuzzy Riccati differential equations

There are many applications of optimal control theory especially in the area of control systems in engineering. In this paper, fuzzy quadratic Riccati differential equation is estimated using neural networks (NN). Previous works have shown reliable results using Runge-Kutta 4th order (RK4). The solution can be achieved by solving the 1st Order Non-linear Differential Equation (ODE) that is found commonly in Riccati differential equation. Research has shown improved results relatively to the RK4 method. It can be said that NN approach shows promising results with the advantage of continuous estimation and improved accuracy that can be produced over RK4.

Solution of the Fuzzy Schröodinger Equation in Positron-Hydrogen Scattering Using Ant Colony Programming

In this paper, solution of Takagi-Sugeno (T-S) fuzzy Schrodinger equation with linear potential in Positron-Hydrogen scattering is obtained using ant colony programming (ACP). The ACP solution is equivalent or very close to the exact solution of the problem. Accuracy of the solution computed by ACP approach to the problem is qualitatively better. The solution of this novel method is compared with the traditional Runge Kutta (RK) method and Numerovs method. An illustrative numerical example is presented for the proposed method.

A Multiagent Transfer Function Neuroapproach to Solve Fuzzy Riccati Differential Equations

A numerical solution of fuzzy quadratic Riccati differential equation is estimated using a proposed new approach for neural networks (NN). This proposed new approach provides different degrees of polynomial subspaces for each of the transfer function. This multitude of transfer functions creates unique “agents” in the structure of the NN. Hence it is named as multiagent neuroapproach (multiagent NN). Previous works have shown that results using Runge-Kutta 4th order (RK4) are reliable. The results can be achieved by solving the 1st order nonlinear differential equation (ODE) that is found commonly in Riccati differential equation. Multiagent NN shows promising results with the advantage of continuous estimation and improved accuracy that can be produced over Mabood et al. (2013), RK-4, and the existing neuromethod (NM). Numerical examples are discussed to illustrate the proposed method.

Excitation of the 3p states in electron-sodium scattering at intermediate energies

A coupled-channel-optical method (CCOM), to investigate the excitation of the 3p states for e−-Na scattering at intermediate energies, is reported. Nine atomic states( Na(3s), Na(3p), Na(4s), Na(3d), Na(4p), Na(5s), Na(4d), Na(5p), Na(5d) ) together with three optical potentials are used in this work. The inelastic differential cross sections (DCS) as well as the reduced Stokes parameters are compared with latest theoretical data and experimental measurements.

Fuzzy Modelling of S-Type Microbial Growth Model for Ethanol Fermentation Process and the Optimal Control Using Simulink

In this work, the fuzzy modelling of S(ubstrate)-type microbial growth model for ethanol fermentation process is built using the sector nonlinearity of Takagi-Sugeno (T-S) fuzzy system. The optimal control for the T-S fuzzy system is obtained using simulink. The motivation is to provide the optimal control by the solutions of the matrix Riccati differential equation (MRDE) obtained from an alternative approach. Accuracy of the solution of the simulink approach to the problem is qualitatively better. An illustrative numerical example is presented for the proposed method.

Positronium formation for e+-Na scattering at low and intermediate energies

There have been various theoretical calculations for positron-sodium scattering that attempt to calculate accurate positronium(Ps) formation cross sections at low and intermediate energies. The recent hyperspherical close-coupling (HSCC) calculations (Le et al. 2005 Phys. Rev. A 71, 032713) has handled the contribution from the positronic bound states to a great extent. Their calculations have further strengthened the argument that the theoretical Ps cross sections at low energies deviate from the predictions of the experimental measurements (Surdutovich et al. 2002 Phys. Rev. A 65, 032713). Here we examine whether the inclusion or the neglect of the positronic bound states in the calculation have any significant effects on the low energy Ps formation cross sections. Thus, we attempt to investigate if large-scale CC calculations are deficient in this respect.