Analytical and numerical study of a pulsatile flow in presence of a magnetic field
December 2015
This paper deals with the effects of magnetic field on heat transfer in a pulsatile flow. A mathematical model is developed to investigate the impact of magnetic field on the velocity and the temperature distributions between two concentric ducts. Finite differences method is used in order to solve the dimensionless governing equations, and implicit schemes for velocity and temperature are obtained. The effects of...
Gravitational effect on surface waves in a homogeneous fibre-reinforced anisotropic general viscoelastic media of higher and fractional order with voids
December 2015
In this paper, gravitational effects on propagation of surface waves in a homogeneous fibre-reinforced anisotropic general viscoelastic media of higher order with voids is investigated. The general surface wave speed is derived to study the effects of gravity on surface waves. Particular cases for Stoneley and Rayleigh waves are discussed. The results obtained in this investigation are more general in the sense that...
Influence of etching on the optical properties of a-plane-oriented ZnO epilayers grown by plasma-assisted molecular beam epitaxy
December 2015
A-plane-oriented ZnO epilayers grown by plasma-assisted molecular beam epitaxy were studied with respect to their optical properties. 10K-photoluminescence (PL) and reflectivity were used to analyze various 2 µm-thick ZnO films etched at different etching profile. The PL spectra show the band emission of the structures become narrower when the etching profile increase. At 0.75 µm etching profile, two...
Dark energy and gravity: Reconsidering Newton’s law of universal gravitation
November 2015
In many theories of gravity, the cause of gravity is neither mentioned nor clarified yet. Dark energy, which makes the universe accelerate and push all matters in the universe apart, has repulsive power. Every matter in space is equally pressured by this repulsive force from all directions. It is assumed that this force comes from infinity in space. However, if matters exist nearby, the matters shield each other from...
On solar wind speed distribution and geomagnetic activity during solar cycle 23 and the early ascending phase of solar cycle 24
November 2015
This paper investigates solar wind repartition through four classes of solar events: (1) one class of quiet days (QD) caused by slow solar wind (V< 450 km/s), and three disturbed activities, where V ≥ 450 km/s, (2) recurrent wind (RW), (3) shock wind (SW), (4) fluctuating wind (FW). RW class is characterized by recurrent high solar wind extended on several solar rotations. SW class is caused by CMEs events. FW...
Polylactic acid (PLA) viscoelastic properties and their degradation compared with those of polyethylene
November 2015
Polyethylene (PE) films are widely used in packaging. PE is a thermoplastic manufactured from nonrenewable petroleum resources. Due to its non–biodegradability, its films have posed serious pollution problems e.g. visual pollution, blockage of gutters and drains, choking of animals etc. Suitable replacements for PE films especially for single use only, are the starch based thermoplastics such as Polylactic acid...
A study of structural, optical and dielectric properties of Eu2O3 doped borate glass
October 2015
Recent technological applications have generated more interest in the studies of different types of glasses. The wide applications of glasses take place due to their interesting properties such as low thermal expansion, high softening temperature, high resistance to chemical attack, high refractive index with low dispersion and mechanical strength. Eu2O3 doped borate glasses were successfully synthesized by melt...
A statistical analysis of Lorentz invariance in entropy
October 2015
After relativity was introduced by Einstein in 1905, several attempts were made to reformulate the other fields of physics to make them consistent with the postulates of Relativity. However, relativistic reformulation remains a bone of contention even today after over a hundred years since Einstein's epoch making papers. This is mainly due to seemingly conflicting yet consistent ways of defining the macroscopic...
Hydrothermal synthesis and structural characterization of an organically-templated open-framework trimolybdates
October 2015
A new one-dimensional coordination polymer formulated as [C2H10N2] [Mo3O10], 1, has been synthesized under hydrothermal conditions in the presence of ethylenediamine. The surface morphology of the as-synthesized product reveals colorless rod-like single crystals of 1. The compound crystallizes in monoclinic space group P21/n with a = 8.08 Å, b =14.39 Å, c = 8.89 Å; β = 97.76°, V = 1033.65(12)...
Crystal size effect on the photoluminescence of calcium aluminate doped Mn2+ nanocrystals
October 2015
Research into finding environmentally friendly, efficient and economic viable nanophosphors is still ongoing as the incorporation of radioactive substances into phosphors to improve their short time luminescence poses serious environmental concern. The present paper investigates the effect of particle size on the, morphology and photoluminescence of environmentally friendly CaAl2O4: Mn2+ nanocrystals. The phosphor was...
Design of an explosive detection system to investigate the luggage of aircraft passenger based on neutron-gamma technique
September 2015
In this study an explosive detection system to investigate luggage of air travelers by the Monte Carlo N-Particle Transport code (MCNP5) has been designed. Concrete as a commonly shielding material was the main part in the designed system. Pulsed neutron generator with 14.1 MeV neutrons was used as a neutron source. Two time gates were used in gamma detection process. The lead was used as a secondary gamma rays...
Ab-initio calculations of magnetic behavior in wurtzite AlxV1-xN compound
September 2015
The density functional theory was employed in order to study the structural, electronic, and magnetic properties of the AlxV1-xN (x=0.25, 0.50, and 0.75) compound in the wurtzite-type structure. The calculations were executed using the method based on pseudopotential, employed exactly as implemented in Quantum ESPRESSO code. For the description of the electron-electron interaction, generalized gradient approximation...
A case study of aeromagnetic data interpretation of Nsukka area, Enugu State, Nigeria, for hydrocarbon exploration
September 2015
The aeromagnetic data of Nsukka area was interpreted qualitatively and quantitatively. Standard Euler deconvolution, Source Parameter Imaging (SPI), Forward and Inverse modeling techniques were employed in quantitative interpretation with the aim of determining depth/thickness of the sedimentary Basin, magnetic susceptibilities and type of mineralization prevalent in the area. Oasis montaj 6.4.2 software and potent...
Existence of solution for a third order three point boundary value problem at resonance
August 2015
Using coincidence degree arguments we prove some existence results, for a third order three point boundary value problem at resonance. Key words: Resonance, coincidence degree, third order, three point boundary value problem.
Effect of tempering on the microstructure and mechanical properties of austenitic dual phase steel
August 2015
This research is focused on the effect of tempering on the microstructure and mechanical properties of 0.23%C austenitic dual phase steel locally manufactured in Nigeria. The as-received steel was normalized in order to annul the thermo-mechanical history of the steel. Thereafter, some of the normalized samples were austenetized at 850°C for 30 min and then slowly cooled in the furnace to the (α+ϒ)...
Geophysical assessment of potential hydrological units in hydrologically challenged geomaterials of Makurdi, Benue State, Nigeria
August 2015
A geo-electric survey employing the Vertical Electrical Sounding (VES) was carried out in order to access the distributions of electrical and hydraulic parameters of hydro-geologic units in some locations of Makurdi where groundwater resources are difficult to tap. A total of fifteen geo-electric soundings were acquired. The contour maps were generated using the results. From the bulk aquifer resistivity and water...
Performance enhancement of incoherent spectral amplitude encoding-optical code division multiple access (SAE-OCDMA) by using dispersion compensation fiber Bragg grating (FBG)
August 2015
Incoherent spectral amplitude encoding optical code division multiple access (SAE-OCDMA) based on fiber Bragg grating (FBG) is one promising technique aim to improve local area networks to have longer span telecommunication network type. In this study, the performance enhancement incoherent SAE-OCDMA is achieved when a dispersion compensation fiber Bragg grating (DCFBG) and erbium doped fiber amplifier (EDFA) are used...
General Relativity support from the double pulsar
August 2015
After the final publication of the Theory of General Relativity by Albert Einstein in 1916, experimental confirmation rested on three astronomical tests. These were the amount of bending of starlight at the edge of the Sun, the change in frequency of light emanating from the gravitational field of the Sun and an explanation in terms of the theory of a remnant quantity in the perihelion advance of Mercury which had been...
Electrical conductivity and uniaxial shear tests on soil samples
August 2015
Soil properties should be well known for the earthquake-resistant structural design studies and other engineering researches. It is aimed to understand the region's soil-structure properties as a result of the practices carried out to determine the mechanical properties and elastic-dynamic character of the units under load. Accordingly, considering the factors that affect the physical and mechanical properties such...
Hydrogeophysical study of aquifer characteristics in some parts of Nsukka and Igbo Eze south local government areas of Enugu State, Nigeria
August 2015
Resistivity survey was carried out in some parts of Nsukka and Igbo Eze south local government areas of Enugu State, in order to evaluate the groundwater conditions of the area. The area is devoid of surface water and lack of proper knowledge of the aquifer has affected the extraction and development of groundwater in the area since it is the major source of water. Resistivity, thickness, depth, curve frequencies and...
Atom-field interaction, hydrogen atom and nature of detuning
July 2015
The nature of detuning in transition probabilities in atom field interaction has been investigated in the light of hydrogen atom problem. It has been shown that the detuning bears a striking similarity with the principal quantum number n in hydrogen atom. Key words: Induced resonant transition, detuning, hydrogen atom.
Synthesis and magnetic characterization of ZnMnO3 nanoparticles
July 2015
ZɳMɳO3 nanoparticles system was prepared by the sol-gel auto-combustion method, in order to analyze the structure and magnetic behavior presented in such compound prepared by a new alternative route of synthesis. Structural characterization, bonds, morphology and size were performed by X-ray diffraction (XRD), infrared spectroscopy (IR) and electron microscopy (TEM) and additionally an optical characterization...
Nanocrystalline Cadmium sulfide (CdS) thin film synthesized at different dip times by chemical bath deposition technique
July 2015
Nanocrystalline Cadmium sulfide (CdS) thin films were prepared by chemical bath deposition technique on a glass substrates at a temperature of 80°C and at different deposition times with composition of cadmium chloride (CdCl2), thiourea (CS (NH2)2), ammonia solution (NH4OH) and triethanolamine (TEA) solution. The characterization of thin films was carried out for the structural, morphological and optical...
The generalized projective Riccati equations method and its applications for solving two nonlinear PDEs describing microtubules
July 2015
Microtubules (MTs) are major cytoskeletal proteins. They are hollow cylinders formed by protofilaments (PFs) representing series of proteins known as tubulin dimers. Each dimer is an electric dipole. These diamers are in a straight position within PFs or in radially displaced positions pointing out of cylindrical surface. In this paper, the authors demonstrate how the generalized projective Riccati equations method can...
Optical and structural properties of lead sulphide (PbS) thin films synthesized by chemical method
July 2015
The influence of dip times on the lead sulphide (PbS) thin films deposited on glass slide substrates via chemical bath deposition (CBD) technique using chemical precursors, nitrate, and thiourea, ) in alkaline medium at 300 K was investigated. The optical, structural and morphological studies were performed by UV-vis spectophotometry, X-ray diffraction (XRD) and scanning electron microscopy (SEM) respectively. The XRD...
Consistency of electrical analogy approach in the prediction of through thickness thermal conductivity of fiber reinforced plastic (FRP) composites with orientation of the square unit cell
July 2015
From the literature, it is found that two different criteria were followed for the prediction of transverse thermal conductivity (K2) of fiber reinforced plastic (FRP) composites. In the first criterion, the internal anisotropy of the lamina is assumed negligible and K2 is estimated using simple Fourier’s law of 1-D heat conduction applied to representative volume element (RVE). Whereas in the second approach, an...
Particle production in proton-proton collisions
June 2015
Proton-proton collision is a simple system to investigate nuclear matter and it is considered to be a guide for more sophisticated processes in the proton-nucleus and the nucleus-nucleus collisions. In this article, the authors present a phenomological study of how the mechanism of particle production in pp interaction changes over a wide range of interaction energy. This study is done on data of charged particle...
Analysis of Hermite’s equation governing the motion of damped pendulum with small displacement
June 2015
This paper investigates simple pendulum dynamics, putting damping into consideration. The investigation begins with Newton’s second law of motion. The second order differential equation governing the motion of a damped simple pendulum is written in form of Hermite’s differential equation and general solution obtained by means of power series. The results obtained are in agreement with the existing ones, and...
Microwave propagation attenuation due to earth’s atmosphere at very high frequency (VHF) and ultra-high frequency (UHF) bands in Nsukka under a clear –air condition
June 2015
The microwave propagation attenuation due to earth’s atmosphere under a clear-air condition for fade depth of 10 dB was investigated using refractivity data calculated from weather vagaries measurement carried out between January and December 2008. The International Telecommunication Union-Radiocommunication Sector (ITU-R) model for multipath fading for small percentage of time with link distance of 100 km was...
Outdoor performance analysis of a monocrystalline photovoltaic module: Irradiance and temperature effect on exergetic efficiency
June 2015
Studies realized on the performance of photovoltaic modules have shown that analysis of the effect of meteorological parameters is crucial in prediction and evaluation of performances; and production of solar systems. This paper highlights the performing analysis of a monocrystalline silicon photovoltaic module. The aim of this work is to study the effect of irradiance and temperature on module performance in a real...
Variational homotopy perturbation method for solving the generalized time-space fractional Schrödinger equation
June 2015
We suggest and analyze a technique by combining the variational iteration method and the homotopy perturbation method. This method is called the variational homotopy perturbation method. We use this method for solving Generalized Time-space Fractional Schrödinger equation. The fractional derivative is described in Caputo sense. The proposed scheme finds the solution without any discritization, transformation or...
Oscilating magnetic field an anti malaria therapy
May 2015
The effect of oscillating magnetic fields (OSMF) on malaria infected albino rats of about three weeks old was investigated. Ten malaria parasite - infected rats were obtained from the Department of Parasitology, University College Hospital Ibadan. The rats were randomly divided into an experimental and a control groups, of five animals each. The rats in the experimental group were exposed to OSMF of 41mT for fourteen...
Computational analysis of the effective parameters on two-phase bubbly water flow in a ramjet propulsion system
May 2015
A computational study of the flow field characteristics and the performances of two-phase bubbly flow in water jet of a ramjet propulsion system with a diverging-converging nozzle has been performed. The analysis use a finite volume approach for the main flow coupled numerically with the Lagrangian equations for the bubbles motion including the change of bubbles radii with time. Computed results for an...
Evaluation of tannery effluent content in Kano metropolis, Kano State Nigeria
May 2015
A field experiment was carried out to evaluate heavy metals and physiochemical concentration of tannery effluents from Kano metropolis. Fifteen samples from five selected tannery industries from Sharada and Challawa industrial estate were collected and determined for heavy metals using atomic absorption spectrophotometric method (AAS) and the result of the study showed that the range mean and standard deviation values...
Analytical and numerical solution of heat generation and conduction equation in relaxation mode: Laplace transforms approach
May 2015
In this article analytical solution of one-dimensional heat equation in relaxation mode of heat generation and conduction using Laplace transforms method is presented. The model adopted takes into account finite velocity of heat propagation, and relaxation of heat source capacity. The properties of heat source terms in four different cases are incorporated in the model and investigated. Temperature distributions and...
Study on laser etching mechanism of aluminum thin film on polyimide
May 2015
In order to study the laser etching mechanism for aluminum thin film on polyimide substrate, the etching process was simulated by the finite element analysis software ANSYS, and etching profile was predicted. A theoretical model was established by comparing the simulated etching results with calculated ones; it was presumed that the etching process was firstly a thermal dominant one, then a photochemical interaction...
Solutions of the Klein-Gordon equation for l≠0 with position-dependent mass for modified Eckart potential plus Hulthen potential
May 2015
In this paper we solve analytical the position-dependent effective mass Klein–Gordon equation for modified Eckart potential plus Hulthen potential with unequal scalar and vector potential for l≠0. The Nikiforov-Uvarov (NU) method is used to obtain the energy eigenvalues and wave functions. We also discuss the energy eigenvalues and wave functions for the constant-mass case. The wave functions of the system are...
Neutron and gamma-ray shielding properties of modified Ni- Ti- X Mo maraging steels
April 2015
MCNP5 program was used to investigate the neutron and gamma shielding properties of Ni-Ti- X Mo maraging steels. The MCNP5 program experimental setup was designed using neutrons of 14.1 MeV from sealed neutron tube and 60Co as a gamma ray source. Particular attention was given to the shielding properties of neutron and gamma for low nickel free cobalt, titanium containing modified maraging steel in correlation to the...
Two methods for extracting the parameters of a non-ideal diode
April 2015
We describe two methods of extracting physical parameters of a non ideal p-n diodes. These include the ideality factor, saturation current and series resistance. The proposed techniques that treat extraction parameters, using the current-voltage characteristic (I,V) forward biased. The first method is to learn three different points of the curve, with the coordinates of these points, one can generate a system of...
Surface and thermodynamic studies of micellization of surfactants in binary mixtures of 1,2-ethanediol and 1,2,3-propanetriol with water
April 2015
Surface physico-chemical and thermodynamic studies of some aqueous surfactant solutions were carried out by employing conductance, surface tension and dye solubilization (UV-Vis absorption spectroscopy) techniques. From conductivity and surface tension measurements, critical micelle concentration (CMC), counter-ion association constant (α), equivalent conductance at infinite dilution (λo), surface exess...
Relativistic causality versus superluminal communication: Is the quantum mechanics a semi-empirical theory?
April 2015
The work analyzes the compatibility between the classical freedom, the local relativistic causality and the non-local behavior of quantum mechanics in the frame of the stochastic approach of the quantum hydrodynamic analogy (SQHA). The work describes the role of the quantum potential in generating the quantum non-local dynamics in a fluctuating environment. The analysis shows that it is possible to maintain the concept...
Development of an approach for mapping of features thermal and hydric of watersheds: Case of the watershed of Brezina (Northwest of Algeria)
April 2015
The objective of the present study is to present the parameters of the hydrological assessment of a steppe area from the data of remote sensing. ¶Adopted methodology rests on the cartography of the various parameters of the hydrous and energy balance on one year scale. ¶Several methods are used. ¶Thus, for cartography of precipitations, one uses in a combined way the relief, the distance of the sea and...
Privacy preserving data publishing: Review
April 2015
Privacy preserving data publishing (PPDP) methods a new class of privacy preserving data mining (PPDM) technology, has been developed by the research community working on security and knowledge discovery. It is common to share data between two organizations in many application areas. When data are to be shared between parties, there could be some sensitive patterns which should not be disclosed to the other parties....
Hydrocarbon trapping mechanism and petrophysical analysis of Afam field, offshore Nigeria
April 2015
The structural trapping mechanism and petrophysical attributes of Afam field, offshore Niger Delta was evaluated using 3D seismic reflection data and composite well logs data. The structure maps and seismic sections show that the anticlinal structure at the centre of the field, which is tied to the crest of the rollover structure assisted by faults, is the principal structure responsible for the hydrocarbon entrapment...
Studies on structural, surface morphology and optical properties of Zinc sulphide (ZnS) thin films prepared by chemical bath deposition
March 2015
Zinc sulphide (ZnS) thin films have been prepared by chemical bath deposition method. X-ray diffraction (XRD) is used to analyze the structure and crystallite size and scanning electron microscopy is used to study the particle size and morphology of ZnS thin film. Optical studies have been carried out using UV-Visible-NIR absorbance spectrum. The band gap value of the film is calculated and it is found to be 3.45 eV....
Soil carbon storage in dominant species of Mangrove Forest of Sarawak, Malaysia
March 2015
Carbon storage in forest ecosystems involves inordinate components including plant biomass carbon and soil carbon. Sequestration of carbon along with other aggressive conservation efforts helps to reduce the increasing negative impact of global warming on the environment and mangroves as the coastal forest. The objective of this study was to assess the soil carbon storage of dominant plant species of Awat-Awat Mangrove...
Teaching the effect of variables on the brightness of a light bulb in a simple electrical circuit using a pneumatic system model (PSM)
March 2015
An experiment-based analogical pneumatic system model (PSM) was developed in this study for the purpose of teaching 5th grade students (11 years old) the variables that have an effect on the brightness of a light bulb in a simple electric circuit. Understanding the analogical relationship between source and target in teaching the variables that have an effect on the brightness of a light bulb in a simple electric...
Multi-objective optimization of hybrid PV/wind/diesel/battery systems for decentralized application by minimizing the levelized cost of energy and the CO2 emissions
March 2015
The main objective of this paper is to propose a methodology to design and optimize a stand-alone hybrid PV/wind/diesel/battery minimizing the Levelized Cost of Energy (LCE) and the CO2 emission using a Multi-Objectives Genetic Algorithm approach. The methodology developed was applied using the solar radiation, temperature and the wind speed collected on the site of Potou located in the northwestern coast of Senegal....
Optical properties of ZnO thin films deposed by RF magnetron
March 2015
We have grown ZnO thin films on glass substrate by R.F magnetron sputtering using metallic zinc target. The influences of some parameters on thin film optical properties were assessed. They exhibited extremely high resistivity of 1012 Ω.cm, an energy gap of 3.3 eV at room temperature. It was found that a R.F power of 50 W, a target to substrate distance of 70 mm, very low gas pressures of 3.35 x 10-3 Torr of argon and...
Behavior architecture controller for an autonomous robot navigation in an unknown environment to perform a given task
March 2015
The aim of this paper is to carry out navigation task in an unknown environment with high density obstacles using an autonomous mobile robot. Fuzzy logic approach is used for the robot planning because the output varies smoothly as the input changes. If the navigation environment contains one or more obstacles the robot must be able to avoid collisions. The robot uses the obstacle avoidance controller in order to reach...
Page 5 of 52, showing 50 records out of 2572 total, starting on record 201, ending on 250
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