November 2009
Calculation of the Mie scattering field inside and outside a coated spherical particle. Vol. 3 (1), pp. 038-041, January, 2008
An error was discovered in our paper published in this Journal (Suzuki and Lee, 2008). The second term in the numerator of Equation (9) should read -m2 x Bn n-1(x2) instead of -m2 x Bn n(x2). Because of this error, the data in Figures should also be corrected as shown below.
November 2009
Utilization of greenhouse effect for solar drying of cassava chips
An indirect passive solar dryer was designed, constructed and tested. The dryer was designed to accommodate a total quantity of 45 kg and was tested by carrying out three experiments with fresh cassava chips of approximate sizes of 2.5, 3.0 and 3.5 cm. The highest temperature recorded during the experiments was 60.5°C. The average result shows that the 3.0 cm chips inside the drying chamber were dried from 65% (187%...
November 2009
Characterisation of the core-binding properties of fatty - based oils
Core-binding properties of beniseed and melon oils are hereby characterised with a view to finding alternatives to the imported foundry core oils that deplete Nigeria’s foreign exchange. Clay and sand samples collected from Niger and Plateau states respectively were blended with varying proportions of core-oils in order to assess their functional properties. Baked strength of 3,223.41 kNm-2 obtained for the...
November 2009
Optimization of design tolerance and asymmetric quality loss cost using pattern search algorithm
Tolerances have a significant impact on manufacturing cost and product quality. In the design of discrete part shapes, the specification of tolerance constraints can have major consequences for product quality and cost. Traditional methods for tolerance analysis and synthesis are time consuming and have limited applicability. A more scientific approach is often desirable for better performance to overcome this...
November 2009
Removal of xylene in gas - phase using compost - ceramic ball biofilter
Biofiltration is fast emerging as a feasible option for treating odorous compounds and other volatile organic compounds (VOCs) from process waste - gas streams using microorganisms attached to porous support matrix. Compost, owing to its inherent physico-chemical and biological characteristics, has shown to be a promising filter material in biofiltration to treat both hydrophobic and hydrophilic gas - phase VOCs at low...
November 2009
Design and synthesis of FPGA for speed control of induction motor
The industrial motor control is quickly changing from micro to nanotechnology design with speed and performance based design implementation. Considering accuracy and synchronism of output response, the attention has been brought to fully digitized design to adopt Space Vector Pulse Width Modulation (SVPWM) as a control technique for three phase Induction Motors due to its resulted advantages in harmonic reduction. Very...
November 2009
Voltage standing wave ratio measurement and prediction
In this work, Voltage Standing Wave Ratio (VSWR) was measured in a Global System for Mobile communication base station (GSM) located in Evbotubu district of Benin City, Edo State, Nigeria. The measurement was carried out with the aid of the Anritsu site master instrument model S332C. This Anritsu site master instrument is capable of determining the voltage standing wave ratio in a transmission line. It was produced by...
November 2009
Exponential chaos lag synchronization of nonlinear bloch equations
This paper proposes a new exponential lag synchronization (ELS) method for chaotic behavior in nonlinear Bloch equations. An ELS controller that is based on Lyapunov theory and linear matrix inequality (LMI) approach is presented to guarantee the exponential synchronization of drive and response systems. The proposed controller can be obtained by solving a convex optimization problem represented by the LMI. A simulation...
November 2009
Analysis of non-newtonian fluid flow in a stenosed artery
The numerical illustration presented at the end of the paper provides the results for the resistance to flow, apparent viscosity and the wall shear stress through their graphical representations. It has been shown that the resistance to flow, apparent viscosity and wall shear stress increases with the size of the stenosis but these increases is comparatively small due to non-Newtonian behavior of the blood indicating...
November 2009
A characterization of H- strictly convex hypersurfaces in de Sitter space
In this study, we introduce a H-strictly convex hypersurface in the 6-dimensional unitary de Sitter space and give a lower bound approximation for the Ricci curvature of such hypersurfaces under some appropriate conditions. Key words: Ricci curvature, H-convex submanifold, hypersurface, de Sitter space.
November 2009
Analysis of inventory-production systems with Weibull distributed deterioration
We studied the inventory-production system with two-parameter Weibull distributed deterioration items. The solution of optimal inventory production control problem with Weibull distribution deteriorating item was revisited based on Baten and Kamil (2009) and carried out using Pontryagin maximum principle. It was also illustrated with an example. The overall inventory and production control were tested for different...
November 2009
Equilibrium and continuous flow studies on the sorption of Congo Red using ethylenediamine modified rice hulls
The effectiveness of using ethylenediamine rice hulls (EDA-RH) to remove Congo Red (CR) from synthetic dye solution was carried out in batch and column experiments under various experimental conditions. Surface morphology analysis was carried out also using atomic force microscopy (AFM). The experimental data obtained at different initial dye concentrations fitted well to pseudo-second order kinetic model. Application...
November 2009
Removal of Pb2+ and Cr6+ ions from aqueous solution by earthworm cast soil
The problem of removing pollutants from aqueous wastewater is growing with the increase in water pollution owing to enhanced industrial activities. Three earthworm cast soil types were studied. Modified and unmodified types were prepared and used for removal of lead and Chromium ions. At about 298 K, the earthworm cast soil types, modified and unmodified removed lead and Chromium ions from aqueous solution. Both...
November 2009
The effect of mercerization media on the physical properties of local plant bast fibres
The effect of using different mercerization media on some mechanical properties of local plant bast fibres, Roselle (Hibiscus sabdariffa), kenaf (Hibiscus cannabinus), okra (Hibiscus esculentus), Baobab (Adansonia digitata) respectively, were generally investigated. The fibres from these sources were purified using the retting method which involved heating with 15% ammonium oxalate followed by scouring using 2% sodium...
November 2009
Theoretical analysis of water distillation using solar still
In developing countries, lack of safe and unreliable drinking water constitutes a major problem. To alleviate this problem, a solar still was designed and tested in Mubi, Adamawa State of Nigeria. The radiation from the sun evaporates water inside the solar still at a temperature higher than the ambient. The principle of operation is the greenhouse effect provided with the glass cover. Energy balances are made for each...
November 2009
Electrical characteristics of (N2-H2) gas mixture DC glow discharge
The electrical characteristics of DC Nitrogen-Hydrogen mixture glow discharge were investigated. The discharge current-voltage (I-V) characteristic curves of the discharge were measured at different gas pressures and gas mixture percentage. The axial distribution of both potential and electric field were studied at different H2percentage. The existence of the reversal electric field in the negative glow region was...
November 2009
Determination of integrated absorption cross-section, oscillator strength and number density of caffeine in coffee beans by the integrated absorption coefficient technique
The integrated absorption cross-section of caffeine in water and dichloromethane, in the wave number regions of 20,000 – 39,062 cm-1 at room temperature, were (4.44 ± 0.18) × 107 and (4.32 ± 0.11) × 107 L mol-1 cm-2, respectively. The corresponding calculated values for oscillator strength of caffeine in water and dichloromethane were 0.19...
November 2009
Influence of hydrogen plasma on properties of transparent PEDT/PSS thin films
Poly (3, 4-ethylene dioxy thiophene)/ poly (styrene sulfonic acid) conductive polymer was deposited on glass substrates through Dip-coating method. These films were subjected to hydrogen plasma in order to evaluate the probability of resistivity reduction. Their electro-optical behavior and structure were studied before and after this process. Hydrogenation at a substrate temperature of 80°C for 30 min reduced the...
November 2009
On pre-service science teachers' preexisting knowledge levels about basic astronomy concepts
A curriculum to train teacher candidates is a very important factor in developing teacher candidates’ conceptual understanding of scientific concepts. Teacher candidates have a dramatic impact on students’ ability to understand and construct new knowledge of the concepts. The purpose of this study was to determine the preconceptions and misconceptions of teacher candidates about basic astronomy concepts....
November 2009
The polarization effects of the n-9Be neutron elastic scattering
The differential cross section of the n-9Be neutron scattering and polarization effects is calculated in the framework of the eikonal approximation theory. In this paper by taking explicitly into account the composite quark structure of nucleons exchange effects we eliminate some discrepancies between the theory and the data that were recently pointed out. Key words: Neutron scattering,...
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