September 2011
Review of Erbium-doped fiber amplifier
Data communication systems are increasingly employing optical fiber communication systems (OFCS) as the transmission paths for information. Various types of optical amplifiers have been developed in OFCS to amplify optical signals. In particular, the Erbium-doped fiber amplifier (EDFA) is one example of an optical fiber amplifier that is widely known for use in amplifying optical signals. The most significant points in...
September 2011
Lubricating grease from spent bleaching earth and waste cooking oil: Tribology properties
The recovery of waste from many industrial production plants and its applicability in product development may be an incentive to industry, since the use of such squander could represents a cheaper source of raw material for many of the important processes utilized in further manufacturing. This paper presents the incorporated of wastes in industries particularly palm oil industries for new multi-purpose grease. Spent...
September 2011
Weakened Mannheim curves
In the discussion of Bertrand and Mannheim curves, it is always assumed (explicitly or implicitly) that the curvature is nowhere zero. In this paper, we adapt this requirement on the Mannheim curves and investigate into the properties of two types of similar curves (the Frenet-Mannheim curves and the weakened Mannheim curves) under weakened conditions. Key words: Mannheim curves, Frenet-Mannheim...
September 2011
Natural lift curves and the geodesic sprays for the spherical indicatrices of the involutes of a timelike curve in Minkowski 3-space
The aim of this paper is to determine criteria of being integral curve for the geodesic spray of the natural lift curves of the spherical indicatrices of the involutes of a given timelike curve in Minkowski 3-space. Key words: Minkowski space, involute-evolute curve couple, geodesic spray, natural lift curve
September 2011
Review of Erbium-doped fiber amplifier
Data communication systems are increasingly employing optical fiber communication systems (OFCS) as the transmission paths for information. Various types of optical amplifiers have been developed in OFCS to amplify optical signals. In particular, the Erbium-doped fiber amplifier (EDFA) is one example of an optical fiber amplifier that is widely known for use in amplifying optical signals. The most significant points in...
September 2011
A novel algorithm for solving fuzzy differential inclusions based on reachable set
In this paper, a numerical method for solving th-order fuzzy differential inclusions with fuzzy initial conditions is considered. A scheme based on the classical Taylor method is discussed in full details, which is followed by a complete error analysis. The method is illustrated by solving some linear and nonlinear fuzzy initial value problems. Key words: Differential inclusions,...
September 2011
An efficient two step Laplace decomposition algorithm for singular Volterra integral equations
The aim of this article is to introduce a new reliable algorithm, namely two-step Laplace decomposition algorithm (TSLDA). This new algorithm provides us with a convenient way to find exact solution with less computation as compared with standard Laplace decomposition algorithm (LDA). The proposed algorithm is use to solve Abel's second kind integral equations efficiently. Key words: Two...
September 2011
Seismic response control of sliding isolated buildings using adaptive fuzzy sliding mode control
The purpose of this paper is to apply adaptive fuzzy sliding mode control for structurally controlling buildings with sliding bearing isolation. Combining fuzzy control and robust control such as sliding mode control, reduces fuzzy rule bases complexity and ensures stability and robustness. We use Lyapunov theory to develop a self-tuning law. Stiffness uncertainty and time delay is used to demonstrate the robustness of...
September 2011
Second law based optimization of a plate fin heat exchanger using Imperialist Competitive Algorithm
This study explores the application of Imperialist Competitive Algorithm (ICA) in thermodynamic optimization of a cross-flow plate fin heat exchanger. The optimization aims at finding the minimum number of total entropy generation units under a given heat duty and pressure drop constraints. Seven design parameters namely, hot side length, cold side length, fin height, fin frequency, fin thickness, number of fin layers...
September 2011
Geophysical investigation of barite deposit in Tunga, Northeastern Nigeria
Gravity and electromagnetic methods were combined to characterize known veins and possibly unveil other concealed veins in Tunga, Northeastern Nigeria. Barite occurs in the study area as vein deposits hosted in clean sandstone rocks. Laboratory analyses of samples show average specific gravity of the variety to vary between 3.16 and 4.24 while the host sandstone rock is 2.63. The study is focused on an area of 0.5...
September 2011
Voltage support and stability improvement using unified power flow controller tuned based on simulated annealing
In this paper, the authors are willing to study the effects of unified power flow controller (UPFC) on voltage support and also stability enhancement at a multi-machine electric power system. Proportional-Integral (PI) type controllers are considered for UPFC control and the parameters of these PI type controllers are tuned using simulated annealing (SA). In order to show the ability of UPFC in voltage control and...
September 2011
Implementation of proportional integral (PI) controlled DSP based cost effective inverter fed speed control of induction motor drive with VisSim/ embedded controls and developer (ECD)
Real-time implementation of PI controller based cost effective inverter fed speed control of induction motor drive using high performance TMS320F2812 DSP with VisSim/ embedded controls and developer (ECD) is presented in this paper. The four switch three-phase inverter (FSTPI) fed drive system consists of a power circuit having an insulated gate bipolar junction transistor (IGBT) based bridge inverter module feeding a 5...
September 2011
Determination of mass attenuation coefficients for natural minerals from different places of Turkey
The mass attenuation coefficients () for some natural minerals taken from different places of Turkey were measured at various low photon energies. The Am-241 radioactive source and Zr and Cd secondary exciter are used to get photons in the energy range 15.8 to 26.2 keV. For each sample and energy, Io and I intensities which are without and after attenuation were measured by a Si(Li) detector...
September 2011
Hi-tech manufacturing process selection problem for very low fraction of defectives with multiple characteristics
Hi-tech manufacturing process selection is the problem of comparing two processes and selecting the one that has a very low fraction of defectives (VLFD). In this paper, we consider process selection by , which is an extension of the widely-used popular indexCpk to cases with multiple characteristics. We propose an analytical approach is proposed to tackle the process selection problem. Hypothesis testing...
September 2011
Synchronization and anti-synchronization of two identical hyperchaotic systems based on active backstepping design
This paper presents an active backstepping design method for synchronization and anti-synchronization of two identical hyperchaotic Chen systems. The proposed control method, combining backstepping design and active control approach, extends the application of backstepping technique in chaos control. Based on this method, different combinations of controllers can be designed to meet the needs of different applications....
September 2011
Mitigating the control channel bottleneck problem in dense cognitive radio networks
We proposed a group-based multi channel media access control protocol for cognitive radio to mitigate the control channel bottleneck issue and to utilize multiple channels efficiently. The existing multichannel media access control (MMAC) based protocols suffer from higher delay to access data channels. This underutilizes data channels and lowers the network goodput in dense cognitive radio networks. Our approach...
September 2011
Feature classification for multi-focus image fusion
Image processing techniques have witnessed increased usage in various real world applications. For any image processing technique, such as image segmentation, restoration, edge detection, stereo matching etc., to be applied successfully, the image under consideration must contain all of the scene objects in focus. Usually, due to inadequate depth of field of optical lenses, especially with larger focal length, it...
September 2011
Ouagadougou station F2 layer parameters, yearly and seasonal variations during severe geomagnetic storms generated by coronal mass ejections (CMEs) and fluctuating wind streams
Solar sources of geomagnetic activity are determined by means of (1) Mayaud aa index values from 1868 to now; (2) sudden storm commencement (SSC) dates and (3) pixel diagrams. From 1966 to 1998 that is, during 33 years severe geomagnetic storms characterised by aa > = 100 nT have been identified and their solar sources determined. During these three solar cycles (cycles 20, 21 and 22) the effects of these solar...
September 2011
Spatial rainfall analysis for an urbanized tropical river basin
Spatial distributions of the storms are important since it is a major factor influencing flood formation in urban areas. However, the spatial allocations of rainfall data obtained from the interpolation method have many uncertainties. Thus, it is the objective of this research to derive the spatial distribution of storm events by using grid-based Kriging method. The best semi-variogram (SV) model is found for Kriging...
September 2011
Meshfree modeling of shape memory alloy wires thermomechanical behavior
In this research, a macro-scale, phenomenological constitutive model for shape memory alloy (SMA) is used in conjunction with energy balance equations to study the evolution of temperature and deformation profiles seen in SMA wires. In this way, the general fully-coupled thermomechanical formula for resistive heating of an SMA wire-initial detwined martensite, leading to strain recovery on heating, is used and numerical...
September 2011
Spatial rainfall analysis for an urbanized tropical river basin
Spatial distributions of the storms are important since it is a major factor influencing flood formation in urban areas. However, the spatial allocations of rainfall data obtained from the interpolation method have many uncertainties. Thus, it is the objective of this research to derive the spatial distribution of storm events by using grid-based Kriging method. The best semi-variogram (SV) model is found for Kriging...
September 2011
Preparation of nickel nanowire within polycarbonate membrane and removing polycarbonate by KrF excimer laser
Nikel nanowire arrays were fabricated by potentiostatic electrodeposition into track-etched polycarbonate (PC) membranes. By electrochemical deposition of nickel, nanowires were grown in the single pores. The nanowires were contacted by sputtering a gold layer on top of the membrane. The distinct difference in laser ablation thresholds offers the selective material removal. After preparation of nanowires, polycarbonate...
September 2011
Path planning for a mobile robot in dynamic environments
Path planning for mobile robots has been gaining extensive research attention recently. Optimal path planning increases the effectiveness of a mobile robot. There are many algorithms to solve the path planning problems overcoming obstacles. However most of the algorithms are applicable to specific shapes or suitable for static environments. This paper introduces a new method of global path planning for a robot moving in...
September 2011
Effect of amending urea with humic acids and acid sulphate on biomass production of Masmadu (Zea mays L.) and selected soil chemical properties
Excessive use of fertilizers especially nitrogenous fertilizers with low management in relation to food safety and environmental pollution has in recent times become a subject of concern. This greenhouse study compared the effect of three different urea-humic acid-acid sulphate soil mixtures on maize biomass production, soil pH, ammonium and nitrate contents, and urea use efficiency compared with urea-N...
September 2011
Optimal route choice in stochastic time-varying transportation networks considering on-time arrival probability
This paper studies the problem of finding a priori optimal paths to guarantee a maximum likelihood of arriving on-time in a stochastic time-varying transportation network. The reliable path can help travelers better plan their trip by measuring the risk of late under uncertain conditions. We first identify a set of mathematical relationships between the on-time arrival probability, mean and variance of the dynamic and...
September 2011
Weighting method for modal parameter based damage detection algorithms
When researchers use bending modes for the purpose of damage detection, a number of available modes are adopted, each of which return a value indicating the severity of damage. Normally, there is a variance in the sensitivity of different modes and the global stiffness change is derived by taking the algebraic average, which is equivalent to the mean in statistical analysis terms. This study proposes weighting method...
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