A preliminary investigation of the signal-to-noise ratio of Toro and Nsukka stations in Nigeria
April 2013
Preliminary investigation of Toro and Nsukka stations from the Nigerian National Network of Seismographic Stations (NNNSS) with respect to Signal-to-Noise-Ratios (SNR) has been performed from noise observation and numerically. The results showed that Toro has higher SNR compared to Nsukka. Six months data collected from the stations in 2012 were used for the study. Nsukka Station in the southern part of Nigeria...
Formation and identification of counter electrojet (CEJ)
April 2013
This study investigates the possible occurrence of counter equatorial electrojet (CEJ) and a quicker method for identification of CEJ. Data from a chain of magnetic observatories of World Data Center for Geomagnetism in Tokyo, Japan, was employed. It is strikingly interesting to observe that most CEJ occurred from morning through new dusk, with almost the same pattern of dHin depression. In Ascension Island (ASC),...
Suggested formulas for half-life time of unstable nuclei: Effect of the isospin asymmetry
April 2013
Using the available data of half-life time of unstable nuclei given that the number of protons is greater than the number of neutrons, an elaboration was made on the dependence of half-life time of these nuclei on the value of the difference between the two numbers, which is referred to as the isospin asymmetry effect. The available data of half-life time was analyzed and two formulas of half-life time were suggested....
Three-dimensional max-type cyclic system of difference equations
April 2013
We show that all solutions of the max-type cyclic system of difference equations , , where , is real positive number, and initial values and , are periodic with period three. Finally we generalized the results for more general system which is finite dimensional system. Key words: Max-type system, difference equations,...
Fuzzy programming and data envelopment analysis for improving redundancy-reliability allocation problems in series-parallel systems
April 2013
Redundancy-reliability allocation problems in multi-stage series-parallel systems under uncertain environments are addressed in this study. First, a multi-objective programming model is formulated for simultaneously maximizing system reliability and minimizing system total cost. Due to the nature of uncertainty in the problem, the fuzzy set theory and technique are used to convert the deterministic multi-objective...
Meditator’s non-contact effect on cucumbers
April 2013
We clearly show the existence of an example of non-contact effect in which the “presence” of a meditator affects bio-samples without physical contact. This is the first report in the world to show this type of effect by scientific measurements. We used edible cucumber slices as bio-sensors and measured the concentrations of gas emitted from the slices by a technique developed by our group. The...
Organic matter and trace metals levels in sediment of bonny river and creeks around Okrika in Rivers State, Nigeria
April 2013
Analysis was carried out on the sediment of Bonny River and creeks around Okrika in order to determine the concentrations of organic matter, lead, nickel, vanadium and cadmium as well as their probable sources and diagenesis. Samples for trace metal analysis were prepared by acid digestion and analysed by atomic absorption spectrophotometry. Organic matter content was determined by the method of Walkey and Black. Mean...
Integrated geophysical investigation for post-construction studies of buildings around School of Science area, Federal University of Technology, Akure, Southwestern, Nigeria
April 2013
An integrated geophysical investigation involving ground magnetic, very low frequency (VLF-EM), and electrical resistivity methods using dipole–dipole array and schlumberger vertical electrical sounding (VES) techniques were conducted around School of Science Area Obanla, Federal University of Technology, Akure, for post construction studies in assessing building foundation integrity. Two traverses were...
The theory of relativity of motion: A new approach
April 2013
For more than a century, people’s belief about special relativity and its formulas was, in fact, inaccurate, because Einstein fails by delaying in the wrong conception. However, one of these formulas is correct, by chance, but the others are incorrect. In the present approach, new expressions for time dilatation, composition of velocities, different masses (energy and inertial masses) and energy are demonstrated...
The strength of the atom localization coupling with the standing-wave field under the dephasing rate influence
April 2013
We investigate the localization of the four-level V-type atom inside a classical standing-wave field through the absorption spectrum of the weak probe field. The expression of the probe absorption spectrum is derived analytically via perturbation treatment of a weak probe field. Numerical results and discussion of the probe susceptibility spectrum behaviour via non-perturbation treatment of the density matrix elements...
Surface waves propagation in fibre-reinforced anisotropic elastic media subjected to gravity field
April 2013
The objective of this paper is to investigate the surface waves in fibre-reinforced anisotropic elastic medium subjected to gravity field. The theory of generalized surface waves has firstly developed and then it has been employed to investigate particular cases of waves, viz., Stoneley waves, Rayleigh waves and Love waves. The analytical expressions for waves velocity and attenuation coefficient are obtained in the...
Estimated electric power consumption by means of artificial neural networks and autoregressive models with exogenous input methods
April 2013
The growth electric energy demand in the industrial and commercial sectors and in public and private buildings represents a problem to estimate electrical consumption in these sectors in order to avoid fines imposed by the respective companies supplying electricity. This study presents artificial neural networks (ANN) and autoregressive models with exogenous input (ARX) models to calculate and to predict the electrical...
Effects of adhesive thicknesses on the stress distribution in prismatic plug-in joints
April 2013
The aim of this study is to research the effects of adhesive thickness, which is one of the factors that affect the stress distribution in the prismatic plug-in joints. The effect of adhesive thickness was theoretically researched in the study. Epoxy-based and acrylic-based adhesives, which are widely used in combining metal joints, were applied. After testing the mechanical characteristics of the adhesives,...
Geoelectrical investigation of aquifer problems in Gosa area of Abuja, North Central, Nigeria
April 2013
The study of aquifer problems in Gosa area of Abuja, North-central Nigeria, has been undertaken. Abuja, the capital city of Nigeria, is underlain by Precambrian basement rocks. Vertical electrical sounding (VES) was carried out at twelve locations within and around the Gosa area. The interpretation of the data obtained from the sounding revealed that six non-aquiferous geoelectrical layers overlie the unfractured...
Extended reach spectrum-sliced passive optical access network
April 2013
Structural numerical analysis of a three fingers prosthetic hand prototype
April 2013
In spite of the importance of the finite element method analysis in the mechanical design, there are a few research works in the prosthetic hands design area that use this tool. This work uses the finite element method to perform a structural analysis of a prosthetic hand prototype during the cylindrical and tip grasp. Through geometric relations, a set of equations was developed in order to define the position of the...
Development of two-dimensional solver code for hybrid model of energy absorbing system
April 2013
This paper treats the dynamic and energy absorption responses of nonlinear spring-mass system using a developed two dimensional solver code. The influence of spring stiffness and various mass configurations on the impact response was investigated using validated models. Results are quantified in terms of important impact response and indicate that an assembly of spring-mass system can be employed to examine the impact...
Comment on "Steady mixed convection stagnation-point flow of upper convected Maxwell fluids with magnetic field" [International Journal of non-linear mechanics, 44(2009):1048-1055]
April 2013
In the present comment, we point out a major flow found in the paper "Steady mixed convection stagnation-point flow of upper convected Maxwell fluids with magnetic field" [International Journal of non-linear mechanics, 44(2009):1048-1055]. Key words: Induced magnetic field, visco-elastic fluid, magnetic Reynold number.
Methodological approach of selecting a vibration indicator in monitoring bearings
March 2013
A rolling bearing is an important element in a rotating machine. Whatever the operating conditions, it is subject to fatigue which causes spalling. In aiming to obtain the most possible real fatigue curve, the vibration level is shown according to different statistical indicators such as the RMS (Root Mean Square), the kurtosis, the crest value, the crest factor and the peak ratio, then to choose the best of them that...
Effective rigid perfectly plastic models to predict deflection and residual velocity of post local failure motion of impulsively loaded circular plates
March 2013
Two deformation models are proposed for clamped circular plates undergoing pulse loadings. By these models, behaviors of plate are studied effectively for the situations before and after local failure. In the first model, it is assumed that impulsive load is uniformly distributed and final deformation is of a spherical dome shape. In order to analyze this model, it assumed that under the shock wave, the mechanism of...
Studies on energy absorption and exposure buildup factors in some solutions of alkali metal chlorides
March 2013
Buildup of photons has been investigated through the solutions LiCl, NaCl and KCl with different salt contents in the energy region 0.015-15 MeV up to a penetration depth of 40 mean free paths. Two types of buildup factors, the gamma ray energy absorption () and exposure buildup factors () have been calculated simultaneously using the five parameter geometric progression (G-P) fitting formula. The influence of photon...
Correction of topological errors in geospatial databases
March 2013
The problems related to geometrical correctness of maps gathered and stored by the geographic information system (GIS) computer systems are still present nowadays. Firstly, digitization of traditional paper maps is still in progress all over the world (the maps are being converted to a vector form and stored in relational databases). Secondly, the existing digital maps are being constantly updated with use of manual and...
Temperature dependence of wall-plug efficiency of high power laser diodes
March 2013
Temperature dependence of wall-plug efficiency of high power laser diodes is theoretically analyzed in terms of experimentally measured parameters of the device. This issue has an influence on the available power output and on the degradation mechanism. High power laser diodes have become increasingly important as the output power of such devices continues to rise. The present calculations revealed that the decrease of...
Temperature dependent current-voltage characteristics of electrodeposited p-ZnO/n-Si heterojunction
March 2013
p-ZnO thin films were grown by electrochemical deposition (ECD) technique on n-Si substrate in order to form the p-ZnO/n-Si heterojunction. Hall measurement and hot probe techniques were used to determine the conductivity type of the ECD grown ZnO thin film. X-ray diffraction measurements revealed the peaks corresponding to the ZnO crystal directions of (002), (101) and (200) confirmed by the Joint...
Effect of milling conditions on the formation of ZnFe2O4 nanocrystalline
March 2013
The effects of milling parameters on the formation of ZnFe2O4 nanocrystalline are studied. Powder mixtures of ZnO and Fe2O3 were milled in high energy vibrant ball milling for different balls to powders mass ratio and milling times. X-ray diffraction and scanning electron microscopy are used to characterize the powders. A crystalline size and lattice parameter are obtained from Scherrer formula and the...
Traffic accident in India in relation with solar and geomagnetic activity parameters and cosmic ray intensity (1989 to 2010)
March 2013
We studied the relation between deaths due to traffic accident in India and geomagnetic activity indices: Kp, Ap, Dst and solar activity (SA) parameters, sun spot number, solar flare index (FI), coronal index (CI) and yearly average of cosmic ray intensity, observed during the period of 1989-2011. It is seen that rate of death by traffic accident are well correlated with these parameters. We have found large negative...
A modified surface wave particle motion discrimination process
March 2013
The difference between polarization properties of surface waves and noise provides us with a simple way of discriminating the fundamental mode surface waves on three-component seismograms. In this process, vertical, radial and transverse component amplitudes at each frequency are weighted according to a theoretical three-dimensional particle motion pattern for a selected window length (WL) and moving interval (MI). For...
Modification of some Albanian wood properties through chemical treatment
March 2013
A study was carried out to evaluate the influence of acetylation on physical properties and gluing ability of some Albanian woods. Three woods were studied: beech (Fagus sylvatica L.), poplar (Populus alba L.) and fir (Abies alba Mill.). For acetylation, pyridine and acetic anhydride were used. After treatment, all the samples were conditioned to 100% relative humidity of air and were measured...
Hydromagnetic flows of a mixture of two Newtonian fluids between two parallel plates
March 2013
The paper aims to study the flow of a binary mixture of electrically conducting, incompressible and viscous fluids between two parallel plates in the presence of a transverse uniform magnetic field. The solution of such a flow model has many applications in magnetohydrodynamic (MHD) power generators, MHD pumps, MHD accelerators, and MHD flowmeters. Exact solutions have been obtained for the following four problems: (1)...
Utilization of paper sludge in clay bricks industry to obtain lightweight material: Evidence from partial replacement of feldspar by paper sludge
March 2013
In recent years, scientific issues related to environmental preservation have acquired great importance and the major challenge to be met is the recycling of materials discarded, causing various damages to the environment by technological development through a disposal of waste. This paper offers a possibility of recovery of waste and byproducts of paper manufacturing (paper sludge) and their use as an addition for...
Mechanical characterization of nickel plated copper heat spreaders with different catalytic activation surface treatment techniques
March 2013
This paper studied the effects of different catalytic activation processes towards intermetallic diffusion and mechanical properties on nickel plated heat spreader after high temperature storage (HTS). Heat spreader performs as medium to dissipate heat from silicon die towards heat-sink and is normally made by copper that is plated with nickel to improve wear resistance and prevent oxidation of copper. Two types of heat...
Performance evaluation of multi objective differential evolution algorithm (MDEA) strategies
March 2013
This study presents the results of comparison of the four strategies of multiobjective differential evolution algorithm (MDEA) namely, MDEA1, MDEA2, MDEA3 and MDEA4 in solving five test problems and an engineering design problem. The test problems are ZDT1, ZDT2, ZDT3, ZDT4 and ZDT6. MDEA is a multiobjective algorithm developed from differential evolution, which is an evolutionary algorithm, to solve multiobjective...
Improvement of electromagnetic wave (EMW) shielding through inclusion of electrolytic manganese dioxide in cement and tile-based composites with application for indoor wireless communication systems
February 2013
The electromagnetic wave absorption characteristics of composite cement-based building material have attracted much interest in recent times. Researchers have mainly focused on the 2 GHz to 12 GHz frequency range while the authors have investigated the mobile and WiFi frequency bands. The determination of characteristics such as reflection loss, absorption, attenuation and shielding effectiveness are crucial in the...
Gamma-ray shielding of concretes including magnetite in different rate
February 2013
The effect of magnetite ore rate on the gamma radiation shielding properties of concrete samples have been measured by using the transmission method for 59.54 and 80.99 keV gamma rays with a NaI(Tl) detector. Linear attenuation coefficients of concrete samples including magnetite in different rates were obtained by Lambert law in which measured gamma ray intensities were used. They were compared with theoretical values...
Effects of growth rate on the physical and mechanical properties of Sn-3.7Ag-0.9Zn eutectic alloy
February 2013
Sn-3.7wt.%Ag-0.9wt.%Zn alloy was directionally solidified upward under different conditions, with different growth rates (V = 3.38 - 220.12 µm/s) at a constant temperature gradient (G = 4.33 K/mm) and with different temperature gradients (G = 4.33 -12.41 K/mm) at a constant growth rate (V = 11.52 µm/s) by using a Bridgman-type directional solidification furnace. The microstructure was observed to be a rod...
The impact of plasma interference profile (PIP) on argon discharge in plasma focus device
February 2013
Radiation emission in a low energy (2.2 kJ, 12 kV) UM plasma focus is studied. The system is operated in Argon filling gas. Enrichment of the radiation emission yield is obtained with an optimized pressure 1.7 mbar. Time resolved radiation emission measurements are made by using an array of PIN diode detectors covered with few Al foil thicknesses, to be found at top arrangement at distance 43.50 cm from the...
Transient mass transfer flow past an impulsively started infinite vertical plate with ramped plate velocity and ramped temperature
February 2013
An exact solution to the problem of a transient free convective mass transfer flow of a Newtonian non-Grey optically thin fluid past a suddenly started infinite vertical plate embedded in a porous medium with ramped wall temperature as well as ramped plate velocity in presence of appreciable thermal radiation and first-order chemical reaction is presented. The resulting system of equations governing the flow is solved...
Effect of geometric parameters on free vibration analysis of thick fiber reinforced plastic (FRP) skew cross-ply laminate with circular cutout
February 2013
The present investigation deals with the free vibration analysis of a thick four-layered symmetric cross-ply skew laminated composite plate with a circular cutout and clamped boundary conditions. Three dimensional finite element models (FEMs) which use the elasticity theory for the determination of stiffness matrices are modeled in ANSYS software to evaluate first five natural frequencies of the laminate. The variations...
Determination of the crust-mantle electrical conductivity-depth structure of Niger Delta using solar quiet day (Sq) current
February 2013
Innovative attempt has been made to study the crust-mantle electrical conductivity-depth structure of the Niger Delta region in Nigeria by applying solar quiet (Sq) day current. The study involved the use of geomagnetic data obtained from Lagos by magnetic data set (MAGDAS), Japan in 2010. Gauss spherical harmonic analysis (SHA) technique was employed which separated the internal and external field contributions to Sq...
Aftershock sequence analysis of 19 May, 2009 earthquake of Lunayyir lava flow, northwest Saudi Arabia
February 2013
Aftershock sequence of 19th May, 2009 Lunayyir earthquake (Mw 5.7) has been recorded by deploying seismic stations immediately after the occurrence of the main shock. Analysis of this sequence clarified that; the major part of cumulative seismic moment released during the first hours after the occurrence of the main shock; their orientation is north west (NW) parallel to the Red Sea axial trend along Najd faulting...
A novel technique for solving Cauchy problem for the third-order linear dispersive partial differential equation
February 2013
To solve Cauchy problem for the third-order linear dispersive partial differential equation, the reduced differential transform (RDT) method is used. Without using any discretization or perturbation the technique gives analytical approximation in the form of rapidly convergent sequence with well-structured terms that can usually be expressed in a compact form. The efficiency and reliability of the method is demonstrated...
Performance analysis of ultra wideband media access control protocol providing two class traffic
February 2013
Ultra wideband (UWB) technology based primarily on the impulse radio paradigm has a huge potential for revolutionizing the world of digital communications especially wireless communications. Multiple packets can be assembled into a single frame at the medium access control (MAC) layer, which can significantly improve the throughput performance. This paper presents a detailed performance analysis for UWB multi-band MAC...
Optimal sensor placement for fault detection and isolation by the structural adjacency matrix
February 2013
In this paper, we consider the optimal sensors placement problem for faults detection and isolation. When the detection and isolation of faults of an existing system’s sensors is impossible or uncertain, a reconfiguration sensor placement of this system should be reconsidered. The propagation of faults (Observability/Detectability) was studied in a structured linear system on a directed graph (digraph). An...
Interface energy of solid cadmium (Cd) phase in the Cd-Pb (Cadmium-Lead) binary alloy
February 2013
The grain boundary groove shapes for the Cadmium (Cd) phase in equilibrium with the Lead (Pb)-Cd eutectic liquid were obtained with radial heat flow apparatus. From the obtained grain boundary groove shapes, the Gibbs-Thomson coefficient, solid-liquid and grain boundary energy for the Cd phase in equilibrium with the Pb-Cd eutectic liquid were determined to be (8.35 ± 0.41) x 10-8 Km, (128.00 ± 12.8)...
Heavy metal removal by ambient-temperature argon plasma modified polyethylene terephthalate (PET) fibers with surface acrylic acid grafting
February 2013
This study utilized the capability of ambient-temperature plasma in modifying the surface properties of materials to activate the nonwoven polyethylene terephthalate (PET) fiber surfaces. The effects of different plasma treatment parameters (such as plasma power, treatment time) and grafting parameters (such as grafting temperature, acrylic acid monomer concentration, grafting time) on the activation and grafting of the...
Econometric modeling and projection of production, import and export of particle board industry in Turkey
February 2013
Although wood is one of the oldest materials used by humans, the production of wood-based panel products has a very short history. The production of panel products constitutes one of the most important developments in forest products industry. In this study, models are established and projections are developed for production, import and export of Turkish Particle board industry by econometric method. As a result of...
A comment on “Robust linear optimization under new distance measureâ€
February 2013
Zhang et al. (2012) proposed a new robust counterpart for linear optimization, and shown the effectiveness of the new model by numerical results of AFIRO and ADLITTLE. In this comment, it is shown that the numerical results in their paper are not true, conversely, the model of Bertimas and Sim (2004) has better optimality than that of Zhang et al. (2012) if the same probability bounds that the -th constraint...
Derivation of the spatially flat Friedmann equation from Bohm-De Broglie interpretation in canonical quantum cosmology
February 2013
Friedmann equations play a central role in cosmology for describing the evolution of the universe. Initially, the Friedmann equations were derived by Alexander Friedmann in 1922. He derived the equations from Einstein’s field equations for a universe which is spatially homogeneous and isotropic. The equations were again derived from Newtonian mechanics by Milne. However in this paper, we derive the spatially flat...
The effects of cow dung inoculum and palm head ash-solution treatment on biogas yield of bagasse
February 2013
Blends of ash solution and water-soaked bagasse with cow dung inoculum were studied for biogas production. Two sets of five biodigesters each of 50 kg capacity were used. The blends were respectively charged into the 50 kg metal prototype biodigesters in the ratio of 3:1 (water:waste). Proximate analyses as well as total solids, volatile solids, carbon content, and calorific value were conducted on the wastes while...
Comparative study of four methods for estimating Weibull parameters for Halabja, Iraq
February 2013
The Weibull distribution is the standard function used by the wind energy community to model the wind speed frequency distribution. In this study, four methods are presented for estimating Weibull parameters (Shape and Scale), namely, Maximum likelihood method (MLM), Rank regression method (RRM), Mean-standard deviation method (MSD), and Power density method (PDM). To compare the methods, a period of 4 years (2001 -...
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