Open Access Original Research Article

The Cohesive Energy Calculations of Some BCC (Li, Cr, Fe, Mo) Lattices Using Density Functional Theory

E. A. Joseph, M. F. Haque

Asian Journal of Physical and Chemical Sciences, Page 1-10
DOI: 10.9734/AJOPACS/2016/30695

The cohesive energies of lithium (Li), chromium (Cr), iron (Fe) and molybdenum (Mo) were computed using density functional theory (DFT). DFT based Fritz Haber Institute-ab initio molecular simulation (FHI-aims) computer code has several input parameters in which some of the variables were optimized. The cohesive energies of Li, Cr, Fe and Mo were calculated within Perdew Wang local density approximations (LDA) of DFT. The results obtained from the calculations of cohesive energies of Li, Cr, Fe and Mo were approximately 1.82eV, 5.33eV, 5.35eV, and 8.02eV respectively; and these results obtained are in the neighborhood of experimentally found values of 1.63eV, 4.10eV, 4.28eV and 6.82eV respectively within reasonable percentage errors.

 

Open Access Original Research Article

Semi-empirical Nuclear Mass Formula: Simultaneous Determination of 4 Coefficients

José Luis Pinedo-Vega, Carlos Ríos-Martínez, Mirna Patricia Talamantes-Carlos, Fernando Mireles-García, J. Ignacio Dávila-Rangel, Valentín Badillo-Almaraz

Asian Journal of Physical and Chemical Sciences, Page 1-10
DOI: 10.9734/AJOPACS/2016/31266

The deduction of 4 coefficients of the semi-empirical mass formula is presented as a function with two constants of proportionality:  which relates the energy of the nuclear volume with volume and  which relates volume with the mass number. Next the development of a proprietary method is presented—one that permits the simultaneous calculation of 4 of the 5 coefficients of the original semi-empirical formula. This method, which is direct and does not employ or require the use of successive approximations or iterations, is sufficiently didactic. It makes use of the experimental binding energies from 6 stable isotopes with a mass number odd-. Subsequently as validation, the coefficients are utilized for the theoretical calculation of the atomic masses of 237 stable isotopes and are compared with the experimental masses. Additionally, the calculation of the coefficients of proportionality  and , the unit nuclear radius , the coefficients of nuclear surface tension , and the nuclear density are presented as well.

Open Access Original Research Article

Biomechanics of a Bifurcating Green Plant, Part 1

W. I. A. Okuyade, T. M. Abbey

Asian Journal of Physical and Chemical Sciences, Page 1-22
DOI: 10.9734/AJOPACS/2016/31458

Analytic study of the xylem flow in a bifurcating green plant is presented. The model involves a set of non-linear differential equations, which are tackled using the perturbation method of solutions. Solutions of the velocity, temperature, concentration, Nusselt and Sherwood numbers are obtained and presented graphically. It is observed that increase in the bifurcation angle increases the flow velocity and concentration, Nusselt and Sherwood numbers, whereas the soil parameter (magnetic field force) decreases the velocity and Nusselt number but increases the concentration and Sherwood number. These results have tremendous effect on the growth and yield of the plant. In particular, the increase in the transport velocity and concentration tend to increase the rate at which water and nutrients are made available to the plant, thus enhancing the growth and yield of the plant (crops); the variation in the electrolytic strength of the soil mineral salt water leading to a lower or higher Lorentz force tends to accounts for why some plants do well in some regions than in the others. Furthermore, it is seen that when the angle of bifurcation is zero (i.e.  α =0) and the magnetic field and thermal diffusion parameter are neglected the flow structures reduce to those of [4].

 

Open Access Original Research Article

Predictor Selection Associated With Statistical Downscaling of Precipitation over Zambia

Libanda Brigadier, David Allan, Banda Noel, Wang Luo, Ngonga Chilekana, Linda Nyasa

Asian Journal of Physical and Chemical Sciences, Page 1-9
DOI: 10.9734/AJOPACS/2016/31545

A non-generative, analog methodology was used to downscale daily precipitation from CMIP5-CNRM-CM5 developed by Météo-France/CNRS and CMIP5-CANESM2 of the Canadian Centre for Climate Modelling and Analysis. The downscaling reduces the 2° resolution GCM output to point station data. Sensitivity experiments for four different predictor variables (PVs) were carried out to examine the most significant PVs for the case of Zambia. ERA-Interim reanalyses was used for calibration (75%) and validation (25%) for the period 1981 – 2012. The Root Mean Square Error (RMSE) was used to compute the predictive power of CNRM-CM5 and CANESM2 by comparing the difference between their simulation results against ERA-Interim. Pearson correlation coefficient (r) was also used to assess the linear relationship between the datasets. Downscaled and observed data were compared and analysed. Results indicate that both CNRM-CM5 and CANESM2 perform well in perfect prognosis over the period 1970 – 2000 averaged over longitude 19°E - 37°E and latitude 22°S - 4°S. Pearson correlation results show that the combination PV2: T850, Q850, and U850 perform well at 95% confidence level. These results fill the knowledge gap of the behaviour of different variables for climate change projections and impact assessment studies in Zambia. Specifically, this study suggests a starting point in the selection of predictor variables for climate change studies in Zambia.

 

Open Access Original Research Article

The Numerical Study of Effects of Thermal Grashof Parameter and Concentration Grashof Parameter on Steady MHD Casson Fluid Flow through Non-Darcy Porous Media, over a Nonlinear Boundary Surface under Slip-conditions

Bhim Sen Kala

Asian Journal of Physical and Chemical Sciences, Page 1-17
DOI: 10.9734/AJOPACS/2016/31014

In the present paper the numerical study of effects of thermal Grashof parameter and concentration Grashof parameter on steady MHD Casson fluid flow through non-Darcy porous media, over a nonlinear boundary surface under slip-conditions is explored. By suitable similarity transformations, the governing boundary layer equations are transformed to ordinary differential equations. The method of the numerical computation with bvp4c, a MATLAB program is applied to solve these equations. The effects of thermal Grashof, concentration Grashof and stretching  index, velocity slip, thermal slip, and concentration slip parameters on velocity, heat transfer, and concentration profiles, Skin-friction, local  Nusselt number and local Sherwood number are computed and discussed numerically and presented through tables and graphs.