Open Access Case study

3D Structural Analysis of Otu Field, Niger Delta, Nigeria

T. N. Obiekezie, E. E. Bassey

Physical Science International Journal, Page 114-126
DOI: 10.9734/PSIJ/2015/16512

3D structural analysis was carried out to evaluate the subsurface structures and hydrocarbon trapping potential of Otu Field, Niger Delta using 3D seismic and well log data. Lithologies and hydrocarbons were initially delineated with the aid of gamma ray, deep resistivity, neutron and density logs of wells. The spatial and depth distribution of lithologies were correlated across the wells in the study area. Network of faults were interpreted allowing identification of growth faults which are listric in character. Three horizons, C10, D10 and D31 were identified and mapped to produce the structure maps. The structure maps of the tops of the reservoirs revealed that the hydrocarbon structures are fault assisted anticlinal structures and they correspond to the crest of the rollover anticlines on the seismic sections. The RMS amplitude attribute extracted on the surfaces revealed bright spots on the region of the anticlinal structures which indicates that the field has economic explorable hydrocarbons accumulations.

 

Open Access Original Research Article

Combined Effects of Hall Current and Magnetic Field on Unsteady Flow Past a Semi-infinite Vertical Plate with Thermal Radiation and Heat Source

K. Srihari

Physical Science International Journal, Page 73-89
DOI: 10.9734/PSIJ/2015/16070

      In the present study combined effects of Hall current and magnetic field on unsteady laminar boundary layer flow of a chemically reacting incompressible viscous fluid along a semi-infinite vertical plate with thermal radiation and heat source is analyzed numerically. A magnetic field of uniform strength is applied normal to the flow. Viscous dissipation and thermal diffusion effects are included. In order to establish a finite boundary condition () instead of an infinite plate condition, the governing equations in non- dimensional form are transformed to new system of co-ordinates. Obtaining exact solution for this new system of differential equations is very difficult due to its coupled non-linearity, so they are transformed to system of linear equations using implicit finite difference formulae and these are solved using ‘Gaussian elimination’ method and for this simulation is carried out by coding in C-Program. Graphical results for velocity, temperature and concentration fields are presented and discussed. The results obtained for skin-friction coefficient, Nusselt and Sherwood numbers are discussed and compared with previously published work in the absence of Hall current parameter. These comparisons have shown a good agreement between the results. A research finding of this study, achieved that the velocity and temperature profiles are severely affected by the Hall effect and magnetic field and also a considerable enhancement in temperature, main and secondary flow velocities of the fluid is observed for increasing values of radiation parameter.

 

Open Access Original Research Article

Growth of CdS Nanoparticles to Fabricate Schottky Barrier

S. Saha, R. Bhattacharya, T. K. Das

Physical Science International Journal, Page 90-96
DOI: 10.9734/PSIJ/2015/17116

CdS nanoparticles have been grown by a simple cost effective chemical reduction method and a Schottky barrier of gold/ nano CdS is fabricated. The grown nanoparticles are structurally characterized by transmission electron microscopy and x ray diffraction. The optical properties of nano CdS is characterized by optical absorption, photoluminescence study. The band gap of the CdS nanoparticles is increased as compared to CdS bulk form.  Capacitance–voltage and current–voltage characteristics of gold / nano CdS Schottky barrier junction have been studied. It is found that these characteristics are influenced by surface or interface traps. The values of barrier height, ideality factor, donor concentration and series resistance are obtained from the reverse bias capacitance–voltage measurements.

 

Open Access Original Research Article

Modified Lee-Low-Pines Polaron in Spherical Quantum Dot in an Electric Field. Part 2: Weak Coupling and Temperature Effect

A. J. Fotue, N. Issofa, M. Tiotsop, S. C. Kenfack, M. P. Tabue Djemmo, A. V. Wirngo, H. Fotsin, L. C. Fai

Physical Science International Journal, Page 97-106
DOI: 10.9734/PSIJ/2015/18439

In this paper, we investigate the influence of an electric field on the ground state energy of a polaron in a spherical semiconductor quantum dot (QD) using the modified Lee Low Pines (LLP) method. The numerical results show an increase of the ground state energy with the increase of the electric field and the confinement lengths. The modulation of the electric and the confinement lengths enables the control of the decoherence of the system. It is also seen that the temperature is a decreasing function of the electron-phonon coupling constant and the longitudinal confinement length, whereas it increases with the electric field strength. 

Open Access Original Research Article

The Computational Limit to Quantum Determinism and the Black Hole Information Loss Paradox

Arkady Bolotin

Physical Science International Journal, Page 107-113
DOI: 10.9734/PSIJ/2015/18414

The present paper scrutinizes the principle of quantum determinism, which maintains that the complete information about the initial quantum state of a physical system should determine the system’s quantum state at any other time. As it shown in the paper, assuming the strong exponential time hypothesis, SETH, which conjectures that known algorithms for solving computational NP-complete problems (often brute-force algorithms) are optimal, the quantum deterministic principle cannot be used generally, i.e., for randomly selected physical systems, particularly macroscopic systems. In other words, even if the initial quantum state of an arbitrary system were precisely known, as long as SETH is true it might be impossible in the real world to predict the system’s exact final quantum state. The paper suggests that the breakdown of quantum determinism in a process, in which a black hole forms and then completely evaporates, might actually be physical evidence supporting SETH.

 

Open Access Review Article

The Thermodynamics of a Gravitating Vacuum

M. Heyl, H. J. Fahr

Physical Science International Journal, Page 65-72
DOI: 10.9734/PSIJ/2015/17812

In the present days of modern cosmology it is assumed that the main ingredient to cosmic energy presently is vacuum energy with an energy density vac that is constant over the cosmic evolution. In this paper here we show, however, that this assumption of constant vacuum energy density is unphysical, since it conflicts with the requirements of cosmic thermodynamics. We start from the total vacuum energy including the negatively valued gravitational binding energy and show that cosmic thermodynamics then requires that the cosmic vacuum energy density can only vary with cosmic scale R = R(t) according to vac  ~ R-v with only two values of being allowed, namely v1 = 2 and v2 = 5/2. We then discuss these two remaining solutions and find, when requiring a universe with a constant total energy, that the only allowed power index is v1 = 2. We discuss the consequences of this scaling of vac and show the results for a cosmic scale evolution of a quasi-empty universe like the one that we are presently faced by.