Open Access Original Research Article

Thermal Behaviour of Bone Cement in Hip Replacement

J. U. Ikekwem, J. L. Chukwuneke, S. N. Omenyi

Physical Science International Journal, Page 1-14
DOI: 10.9734/PSIJ/2018/39318

This work involved the study of heat transfer in a cemented hip replacement. The recent rise in cemented hip replacement in Orthopaedic and trauma surgery is of alarming concern to the material usage and conditions it been subjected to. Bone cementing which is the main technology providing the bonding mechanism between the femur cavity and the prosthesis stem is the polymerization reaction between the powder and liquid monomer which is an exothermic reaction. This heat transfer mechanisms between the bone cement, the prosthesis stem and the femur bone is of concern to biomechanics engineers. The ANSYS 15.0 software was used in conjunction with the Autodesk software to model the scenario and simulate it using steady state thermal-structural analysis. It was found that the temperature that resulted from the exothermic reaction of the PMMA polymer (used as bone cement) raised the temperature in the assembly creating a heat flux amounting to 5.11x10-7W/m2 in which only 2.83x10-7 W/m2 got to the femur bone while the rest was absorbed by the prosthesis stem and the femur bone. The specific heat capacities of PMMA and femur bone were calculated as1.297kJ/kg.K and 0.59kJ/kg.K respectively. The Young Modulus for PMMA was found as 28.78GPa and 18.79GPa for femur bone. These show that it is possible to determine these properties from the simulation studies.

Open Access Original Research Article

Calculation of Temporal Plasmas of XFEL Experiments with a Relativistic Collisional Radiative Average Atom Code

A. J. Benita

Physical Science International Journal, Page 1-26
DOI: 10.9734/PSIJ/2018/40246

In this paper, we illustrate the computational capability of the collisional radiative model ATMED CR for calculating the temporal evolution of accurate atomic populations including nlj-splitting, mean charge and atomic processes rates. The present work contains computed time-dependent plasmas with the average atom code ATMED CR of neon and aluminium created with X-ray Free Electron Lasers proposed in the 10th Non-LTE Code Comparison Workshop. The results for plasma properties can be considered as very precise, according to the electronic temperature profiles registered in experiments of laser created plasmas with duration times of picoseconds and femtoseconds. As a consequence, the Crank-Nicholson implicit numerical iterative temporal module of ATMED CR can be considered a new rapid method for simulating this type of plasmas, avoiding some of the typical difficulties that appear in interpreting results of free electron laser experiments, as very different temporal scales in NLTE regime, enormous matrices of detailed collisional radiative codes, etc.

Open Access Original Research Article

An Analysis of Axial Couette Flow in Annular Region of Abruptly Stopped Pipes

V. Thirumaran, J. A. Weliwita, M. I. M. Ishak

Physical Science International Journal, Page 1-12
DOI: 10.9734/PSIJ/2018/40076

Aims: Flow in annular regions encounters in many fields such as bio-medical, petroleum, aerospace and chemical industries and among them, the flow between two coaxial pipes has rather become interesting due to its asymmetry nature.

Study Design: Theoretical solution and numerical approximation and analysis.

Place and Duration of Study: Department of mathematics, Faculty of Science, University of Peradeniya, Sri Lanka, between August 2017 and January 2018.

Methodology: Yet it is particularly challenging to obtain theoretical solutions. In this paper, we carried out a comprehensive analysis for unsteady, unidirectional and incompressible Couette flow between annulus, when inner and outer pipes were brought to abrupt stop from constant velocities. The velocity of the field is derived by applying the Laplace transformation method. The analytical work is supported by the numerical approximation using Finite Difference Method for the same fluid, which was implemented in MATLAB programming. We illustrate results varying radii of the outer and inner pipe captured by ratio ( η =0.1, 0.3, 0.5 and 0.5) and for different boundary conditions. Flow field was visualized using FDM approximation for selected parameter regime when the flow was suddenly stopped.

Results: Asymmetry of the velocity profile was affected by different radius ratios (η =0.1, 0.3, 0.5 and 0.5 ). Unsteadiness in the flow field was happened due to sudden changes in flow parameters.

Conclusion: The results depicted that radii ratio and boundary condition has a strong impact on the role on changing the flow characteristics and flow parameters.

Open Access Original Research Article

Energy Spectrum of the K-State Solutions of the Dirac Equation for Modified Eckart Plus Inverse Square Potential Model in the Presence of Spin and Pseudo-Spin Symmetry within the Framework of Nikifarov-Uvarov Method

H. Louis, A. I. Ikeuba, B. I. Ita, P. I. Amos, T. O. Magu, O. U. Akakuru, N. A. Nzeata

Physical Science International Journal, Page 1-8
DOI: 10.9734/PSIJ/2018/38209

The exact analytical bound state solutions of wave equations are still very interesting problems in fundamental quantummechanics. However, there are only a few potentials for which these wave equations can be exactly solved. In this paper, Spin and pseudospin symmetries of the Dirac equation for Modified Eckart plus Inverse square potential within a zero tensor interaction   are investigated using the parametric Nikiforov-Uvarov method which is based on the solutions of general second-order linear differential equations with special functions. The bound state eigen value was obtained with some few cases of potential considerations.

Open Access Original Research Article

Morphometric Studies of Pebbles from Ewen Area, Calabar Flank, Southeastern Nigeria: Implications for Paleoenvironmental Reconstruction

Emmanuel Etim Okon, May Okah Asi, Romeo Akombi Ojong

Physical Science International Journal, Page 1-12
DOI: 10.9734/PSIJ/2018/39806

Morphometric parameters of unbroken quartz pebbles recovered from the basal section of Awi Formation exposed around Ewen area, southeastern Nigeria were studied for paleoenvironmental reconstruction. The study involved the determination of the roundness and measurement of the three orthogonal axes (long, short and intermediate) for about 200 pebbles. The pebbles were selected from 20 points across four exposed sections of the Awi Formation around Ewen village. The roundness was determined using the standard roundness chart. The results show that the pebbles are sub-rounded to sub-angular and predominantly compact-bladed. The mean values for the following morphometric parameters: Flatness index, elongation ratio, maximum projection sphericity index and oblate-prolate (OP) index are 0.57, 0.78, 0.74 and 15.65 respectively. These values are in agreement with those of modern fluvial pebbles. This result was integrated with the deductions from bivariate plots of roundness against elongation ratio and sphericity against OP index and they all inferred the deposition of the conglomeratic sandstones in a fluvial setting with subordinate transitional setting.