Solutions of Relativistic Klein-Gordon Equation with Equal Scalar and Vector Shifted Hulthen plus Angle Dependent Potential

We have solved approximately the relativistic Klein-Gordon equation under the special case of equal scalar and vector shifted Hulthen plus angle dependent potential using the  parametric form of NIkiforov-Uvarov method.  The energy eigenvalues and the corresponding  wave functions expressed in terms of a Jacobi polynomial are obtained. The effect of  the angle dependent part on the radial solution is also discussed. We have also discussed few special cases of this potential. Keywords: relativistic Klein-Gordon equation, shifted Hulthen, angle dependent potential, parametric Nikiforov-Uvarov method, centrifugal term. PACS: 03.65Ge; 03.65.Pm; 03.65.Fd; 03.65.-w

Studies on relaxation length of wood by method of gamma radiation

Relaxation lengths of different types of wood were determined using gamma radiation from 60Co source. Results show that oxystigma (Oxystigma spp) has the highest relaxation length of 23.810 cm, while mangrove (Rhizophora spp) has the least relaxation length of 1.247 cm. A mathematical model has been developed for the prediction or determination of density (r) variation of wood with relaxation length. A good agreement (greater than 80%) was observed between the measured values and the predicted ones. With proper choice of the thickness of wood from theoretical evaluation, it was observed that Mangrove (Hard Wood) with thickness of 120 cm almost completely attenuate gamma ray energy in the range 0.1 Mev to 1.836 Mev. Keywords: relaxation Length, wood, and gamma radiation Nigerian Journal of Physics Vol. 17, 2005: 108-11

Preliminary studies on global solar radiation in Mbalmayo, Cameroon

This paper presents preliminary studies on the global solar radiation in a horizontal surface along with the prevailing meteorological conditions measured during the period 1999-2001 in Mbalmayo, Cameroon. Hourly, daily, and mean monthly values of global solar radiation and meteorological data were obtained from the International Institute of Tropical Agriculture automatic weather station of Mbalmayo. The data were processed as daily, hourly, sum of 10-day data for 8.00/12.00/16.00/20.00 hours, decadal hourly, decadal daily, and mean monthly data. The highest measured daily, decadal hourly, decadal daily, and mean monthly data for global solar radiation in Mbalmayo was found to be 29.7, 2.76, 21.8, and 20.1 MJm2, respectively. The highest hourly global solar radiation value up to 182.44 MJm2 was observed between March 21-31, 1999. Apart from the global solar radiation measurements, the main observed meteorological parameters were, soil temperature, temperature, wind speed, precipitation, and relative humidity. The results show that there exist seasonal tendencies in the variation of global solar radiation. The range of variation of these radiations and the distribution puts Mbalmayo has a high potential for solar energy utilization

Comparative Study of Thermal Conductivity Values of Different Percentage Compositions of Ground Arachis hypogea (Groundnut) Husk and Vigna unguiculata (Beans) Husk Compressed Fiberboards

Thermal conductivity values of compressed boards made of ground Arachis hypogea husk and Vigna unguiculata husk as binder at different percentage compositions at a temperature of 303 K were investigated using steady-state method. Other thermal properties including specific heat capacity, density, thermal absorptivity, and diffusivity values were also estimated for the prepared samples. Comparative studies of the determined values for the board at different proportions or ratios of combination of A. hypogeal ground husk with V. unguiculata ground husk reveal that thermal conductivity value decreases with an increase in the percentage content of A. hypogea husk contents. A fitting polynomial regression analysis reveals a correlation coefficient of 99.6%. The range of thermal conductivity values falls within the range of conventional good thermal insulators. Thus, the husks are potential ecofriendly raw materials for insulation board for cold building design and other thermal envelops