December 2009
The application of artificial neural networks technique to estimate mass attenuation coefficient of shielding barrier
This study aims to investigate comparison of radiation attenuation property of harzburgite mineral calculated by Monte Carlo (MCNP) and Artificial Neural Network (ANN). Slab sample modeled in MCNP with 1, 2 and 4 cm thickness was irradiated with parallel beam of monoenergetic particles. Incoming and outgoing particle fluxes were computed with F1 tally. Beer-Lambert equation was used to obtain mass attenuation...
December 2009
Energy performance of electrical support facilities: The case of adaptive re-used historical buildings in Malaysia
Electricity could be the most expensive form of energy used in buildings. Hence, reduction in electricity consumption may save more money than other cost-saving measures. Although the cost of providing and installing electrical equipment represents a relatively small proportion of the total mechanical and electrical (M&E) costs, in historic buildings, however, it is an increasingly significant element in saving the...
December 2009
Effects of introducing periodical polymer gratings on the solar cell
Effects of the light-collecting solar cell with high polymer reflecting gratings and experimental accomplishment of periodical gratings on the solar cell surface are studied. It mainly discusses the way and advantage to enhance the solar cell efficiency by using holographic interference lithography to produce high polymer reflecting gratings on the solar cell. Based on the easy processing method, the theoretically...
December 2009
Binding data analysis for the interaction of ferrocyphen with sodium dodecylsulfate in the presence of sodium benzoate
The binding of ferrocyphen (Fe(C12H8N2)(CN)2) with sodium dodecylsulfate has been studied at various concentration of sodium dodecylsulfate as a function of aromatic counter ion (sodium benzoate) concentration. The unusual scatchard plot has been interpreted using binding capacity concept. The results represents two binding set for all the studied conditions. The value of Hill equation parameter have been estimated and...
December 2009
Isolation and characterization of the organic components of a black indigenous mineral hair dye
Isolation and characterization of the main organic component of a black indigenous mineral dye; Yombotumtum (YT) was carried out. The methods employed include physicochemical characterization using solubility test, melting point, combustion test, organic and inorganic (ash) contents, functional group tests, IR and UV- VIS spectroscopic analysis and preparation of derivatives. The results obtained were...
December 2009
Geothermal gradients in the Chad Basin, Nigeria, from bottom hole temperature logs
Bottom Hole Temperature (BHT) data from 21 oil wells in the Nigerian sector of the Chad Basin were analyzed and interpreted to investigate the thermal structure of the basin. A regional average geothermal gradient of 3.4°C/100 m geothermal gradients in the range of 3.0 to 4.4 °C/100 m were obtained. The gradients are relatively lower at the Northeast and Southwest axis and maximum at the North-centre. These...
December 2009
Measurements of apparent electrical conductivity and water content using a resistivity meter
Measurement of soil water content (Wn), a major interest in many disciplines which requires collection, analysis and interpretation of soil data, may be expensive and time consuming. One way to reduce the cost of it is to measure the soil apparent conductivity (ECa) and to correlate with soil volumetric water content. However, the influences of soil properties such as salinity, porosity, structure, pH and clay content...
December 2009
The ecoclimatic indexes specific for the Arges valley (Fagaras Mountains, the Southern Carpathians, Romania)
The important features of the mountain areas may be synthetically assessed, based on several methods of numerical analysis (a series of indexes) of the ecological potential. In this paper we have analyzed the following indexes: De Martonne’s aridity index, continentality index of Gams, hydrothermal index, pluviothermal index and snow index. To achieve this, climate date obtain from these stations were...
December 2009
Interannual variability of Atlantic hurricane activity and some features of West African climate
The aim of this study is to describe over the Atlantic Ocean and West Africa, the large scale differences between an inactive hurricane period (1991 - 1994) and an active hurricane period (1998 - 2001), before and during the peak of the cyclone season (May - June - July; MJJ and August- September - October; ASO). Over West Africa, the monsoon flow at low level extends more northward during the active period. This period...
December 2009
Calculation of Ricci tensors by mathematica V 5.1
In solution of Einstein field equations it is necessary to contracting Riemann-Christofell tensor. The contraction of Riemann-Christofell tensor or simply the curvature tensor is called the Ricci tensor and denoted by QUOTE . The calculation of Ricci tensor in 3 and especially in 4-dimension is not very difficult but, it is very tedious; and need more time with accuracy. In this paper, the focus has...
December 2009
Bifurcations and chaos in simple dynamical systems
Chaos is an active research subject in the fields of science in recent years. It is a complex and an erratic behaviour that is possible in very simple systems. In the present day, the chaotic behaviour can be observed in experiments. Many studies have been made in chaotic dynamics during the past three decades and many simple chaotic systems have been discovered. In this work, the behaviour of some simple dynamical...
December 2009
Heat and fluid flow analysis in gas turbine blade cooling passages with semicircular turbulators
This paper reports a numerical investigation of heat transfer and flow characteristics in a two-dimensional u-tube over semicircular turbulators. Repeated semicircular turbulators (ribs) are used inside a cooling passage to promote turbulence and enhance convective heat transfer in gas turbine blades to create higher thrust-to-weight ratios. The u-tube has a 180° bend while the turbulators are distributed on both...
December 2009
Simultaneous sensor and hand-sensor calibration of a robot-based measurement system
This paper presents a system for object digitalization by use of a laser stripe triangulation displacement sensor and an industrial MOTOMAN robot. In order to ensure the precision of the scanning system, a novel calibration scheme referred to as one-stage approach is proposed. This procedure mainly utilizes a circular-marked board as calibration target and calibrates the range finder and hand-sensor model simultaneously...
December 2009
The magnetic behaviour of an isolated paramagnetic spin-1 and spin-1/2 degree of freedom
The effect of external magnetic field and temperature on paramagnetic spin-1/2 and spin-1 degree of freedom was investigated. Magnetization m(h,T) and magnetic susceptibility are found to have a direct and inverse behaviour with external magnetic field and temperature respectively. Various limiting cases ofm(h,T) were considered for different temperatures and external magnetic field. The agreement with...
December 2009
Photothermal conversion in a solar collector with tilted walls
This paper presents a performance analysis of a solar air collector with tilted side faces. The northern side wall is tilted at an angle of 38° and other walls are tilted at an angle of 9° relative to the vertical. All these walls are covered with a thin reflective aluminium film. The device may be used as drier, sterilizer or cooker in rural areas. The prototype collector was designed and produced in the Study...
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