Iranian Journal of science and Technology (A: Siences)
No. 2902, 2004

We investigate the boundary-value problem generated by the Sturm-Liouville equation with discontinuous coefficients, eigenparameter dependent boundary conditions and transmission conditions at the point of discontinuity. With a different approach we introduce an adequate Hilbert space formulation, investigate some properties of eigenvalues, Green’s function and resolvent operator, and find simple conditions on the coefficients which guarantee the self-adjointness of the considered problem.

A three-step selective photo-ionization for Gd155 and Gd157 isotopes by pulsed laser was evaluated numerically. Due to large thermal neutron absorption cross sections, these two isotopes in natural gadolinium are good candidates as burnable poison to control reactivity early in the fuel cycle and allow extended fuel burn up. Rate equations have been used to calculate the dynamics of the isotope populations, ionization rate, and selection factor. Doppler broadening, as well as power broadening for atomic energy levels, has been considered in the calculations. The effects of laser intensity, frequency bandwidth, and laser detuning in the ionization process have also been assessed. By applying a variety of conditions, the sensitivity of different parameters in the ionization process was investigated. The results show that the ionization yield increases with the intensities of lasers, and becomes saturated at some specific values. Depending on the energy bandwidth of each state, laser bandwidth and the detuning of lasers greater than particular values can affect the ionization yield. Due to small and finite isotope shifts of energy states, the selection factor can be influenced by detuning and laser bandwidth. From the results, it can be inferred that for Gd155 and Gd157 isotopes, ionization is more sensitive to the first and second laser bandwidth and detuning. From these results, optimum selection factors and ionization by using appropriate laser intensities, bandwidth, and detuning can be achieved.

Here, we have considered the Husimi and Wigner distribution functions. We have, in particular, shown how the uncertainty principle works for the two cases of simple and damped harmonic oscillators when either of these two distributions are used. The conclusion shows that the Husimi distribution function remains non-negative through the phase space but it does not always satisfies the uncertainty principle. On the other hand the Wigner distribution function while becoming negative in certain regions of the phase space do not violate the uncertainty principle.

The elementary reaction of kaon exclusive electroproduction on protons has been studied in a broad kinematical range. Data for the calculation of the form factor of the kaon have been taken at different values of the invariant center of mass energy W in the range W=1.8, 1.85, 1.98, 2.08 (GeV), for one value of the transferred 4-momentum Q2=2.35 (GeV/c)2. In this analysis, we calculated sL and sT by using the Rosenbluth separation. Then the electromagnetic kaon form factor was calculated by Chew-Low extrapolation.

A generalized Heckman model is used for the joint modeling of longitudinal continuous responses and dropout in order to see the influence of a small perturbation of the elements of the covariance structure on displacement of the likelihood. The perturbation from random dropout in the direction of informative dropout is considered for Mastitis data.

The design and application of a fuzzy logic based controller to a leakage current relay was presented in this paper. A novel approach based on fuzzy logic to form the tripping action of leakage current relay was investigated. In addition to the theoretical aspect of fuzzy logic, detection of a leakage current, measurement of the leakage current, determination of its duration, trip opening of faulty cases and detailed system architecture were also introduced. The inspected fuzzy logic technique to control the tripping action of the leakage current relay was intended to improve the performance of conventional leakage current relay control for human safety and system reliability. The relationship between the controlled output of the fuzzy processor and properties of leakage current for the proposed relay was explored by using a graphical output expression. It was observed that the proposed leakage current relay based on fuzzy logic was more reliable than conventional leakage current relay.