Archives-December 

This paper presents effective method and to determine optimal machining parameters in a turning operation on annealed Beryllium copper alloy to enhance the metal removal rate and minimize the surface roughness. The scope of this work is extended to Multi objective optimization. Response Surface Methodology is opted for preparing the design matrix. Artificial Neural Networks are used to train and validate the data prepared through experimentations. Multi Objective Genetic Algorithm is used for optimization of the performance measures of the process. A powerful model would be obtained with high accuracy to analyse the effect of each parameter on the output. The input parameters considered in this work are cutting speed, feed and depth of cut.

The activity concentrations of natural occurring radionuclides, uranium (²³⁸U), thorium (²³²Th), radium (²²⁶Ra) and potassium (⁴⁰K) were measured in geological samples collected from the Accra Plains using a high resolution hyper pure germanium (HPGe) detector. Their radiological parameters were also calculated. ²³⁸U concentration was found to vary from below detection limit to 363.5 Bq/kg. Activity concentration of ²³²Th varied from below detection limit to 370.41 Bq/kg. The activity concentration of ²²⁶Ra ranged from 4.04 Bq/kg to 295.01Bq/kg, whereas, the ⁴⁰K activity concentration varied from 145 Bq/kg to 2274.3 Bq/kg. The absorbed dose rates varied from 18.27 to 479.26 nGy/h. The annual external effective dose rates ranged from 0.02 to 0.51 mSv/y. The radium equivalent activity (Raeq) varied from 29.15 to 986.42 Bq/kg. Value of external hazard index (Hex) varied from 0.11 to 2.66. Good correlations existed between ²³²Th and ²²⁶Ra activity concentrations and the total activity concentration. The Th/U ratios obtained indicated metasomatic activity of the analyzed radionuclides. The gamma ray radiation hazards due to the radionuclides increased with depth. 

Legendre and Chebyshev collocation methods are presented to solve numerically the voltterra-fredholm integral equations with exponential kernel. We transform the Volterra Fredholm integral equations to a system of Fredholm integral equations of the second kind,a system Fredholm integral equation with exponential kernel is obtained and will be solved using Legendre and Chebyshev polynomials.This lead to a system of algebraic equations with Legendre or Chebychev coeffcients. Thus,by solving the matrix equation,Legendre and Chebychev coeffcients are obtained.A numerical example is included to certify the validity and applicability of the proposed technique.

Asynchronous Transfer Mode (ATM) is a connection-oriented packet switching technique that is universally accepted as the transfer mode of choice for Broadband Integrated Services Digital Network. The Quality of Service (QoS) capabilities of ATM is one of its major strength. In this paper we have explore some of the technological challenges and issues which plays important role in the security of ATM networks.

In order to develop a superior formulation for skin decontamination of 99mTc-pertechnetate (a potential radiocontaminant), a topical gel formulation containing disodium edetate was optimized by using 2-factor, 3-level central composite design. Polymer concentration (A) and disodium edetate concentration (B) were selected as the independent variables and the dependent variables were selected as viscosity (Y1), spreadability (Y2) and extrudability (Y3) of the gel. The viscosity of the gel was found to decrease proportionally with spreadability and extrudability, whereas the spreadability was increased proportionally with extrudability. Validation of the optimization study with 13 confirmatory runs indicated a high degree of predictive ability of response surface methodology (RSM). The optimized formulations were evaluated for drug content, in vitro, in vivo, ex vivo and skin irritation studies. The in vitro evaluation of the topical gel efficacy study confirmed the good chelation efficacy of disodium edetate molecules with 99mTc-pertechnetate ions. The ex vivo diffusion kinetics study demonstrated that the permeation rate of 99mTc-pertechnetate through intact skin was decreased to 83.68% after immediate application of disodium edetate gel. In vivo studies demonstrated that the application of topical gel is effective in external decontamination of 99mTc-pertecnetate from male Sprague-Dawley rats. The optimized gels did not produce any dermatological reactions on rats. All the results of the study revealed that disodium edetate loaded topical gel is a promising formulation for the external decontamination of radioactive agents.

The term ‘organizational justice’ refers to the extent to which employees perceive workplace procedures, interactions and outcomes to be fair in nature. These perceptions can influence attitudes and behaviour for good or ill, in turn having a positive or negative impact on employee performance and the organization’s success. The principles of organizational justice are not, on the whole, complex to apply and may be considered more in the vein of ‘sound managerial practice’ than ‘social technology’. While some interventions may be less successful on some occasions or in particular contexts, none is likely to be harmful, and at the very least they will promote a sense that the organization is concerned about fairness. When implemented well, they can make a significant contribution to improving performance, enhancing commitment, and preserving dignity and humaneness.

There is widespread concern that the cumulative effects of the non-response that is bound to affect any long-running longitudinal study will lead to mistaken inferences about change. We focused this work on the Longitudinal Survey of Oyo town covering the existing fifteen (15) Enumeration Areas to show the patterns of response and non-response. The Surveys started in 2008 and a two-stage stratified random sampling scheme was used in selecting 750 households. Household heads were interviewed in five waves (waves 1, 2, 3, 4 and 5). We used an interviewer-administered questionnaire to collect data on the demographic characteristics of the respondents. The Response rates for waves 1 through 5 were 77.86%, 82%, 81.33%, 82% and 80.67% respectively while the non-response rates were 22.14%, 18%, 18.67%, 18%, and 19.33% respectively. The average number of visit ranges from a minimum of 1.2 in Kosobo to a maximum of 4 in Ladigbolu. The average duration of the household interview ranges between a minimum of 7.7 minutes in Monbolaje and a maximum of 18 minutes in Asipa. Finally, fieldwork lasts on average of 11.8 hour in Asipa, but only 6.6 hours in Monbolaje. The most common interview mode is the Pencil-And-Paper (face-to-face) Interview. New entry is linked to eligibility, whereas monotone attrition is mainly due to migration. Occasional responses are due to absences while that of non-responses are due to out of scope and lack of cooperation.

Game Theory may be applied in situations in which a Decision Maker (DM) must take into account the reasoning of other Decision Makers. It has proved to be an enormously fruitful approach to the analysis of a wide range of problems. Any situation in which rivals make strategic choices, to which competitors will respond, can be assessed using game theory analysis. An Oligopoly is a market dominated by a few large suppliers. The degree of market concentration is very high (i.e. a large % of the market is taken up by the leading firms). Firms within an oligopoly produce branded products (advertising and marketing is an important feature of competition within such markets) and there are also barriers to entry. Another important characteristic of an oligopoly is interdependence between firms. This means that each firm must take into account the likely reactions of other firms in the market when making pricing and investment decisions. This creates uncertainty in such markets - which we seek to model through the use of game theory. The purpose of this paper is to develop a purely mathematical approach to determine a Payoff for oligopoly market. The model developed allows the researcher to derive Payoff Matrix in an oligopoly market using only assumption about each firm.

Si-based resonant interband tunneling diodes (RITD) with spacer thicknesses varying from 2.5 to 25 nm was grown and fabricated at Baghdad University. The effect of spacer thickness on the peak-to-valley current ratio (PVCR), peak current density (JP), and voltage swing (VS) was studied for determining the static or dynamic read access memory (SRAM, DRAM). By increasing the tunneling spacer thickness up to 12 nm, RITDs with VS are reduced below 0.3V; this is suitable for low-power tunnel diode SRAM applications. The JP increased as the spacer thickness increased from 2.5nm to 5nm. As the spacer thickness increased above 5nm, the Jp decreased. Using a low-current-density in this paper, a bread-boarded one-transistor tunneling-based SRAM (TSRAM) memory cell with low standby power consumption was demonstrated, where the standby power of this 1T TSRAM is estimated to be 65nW/cell using the 10-?m diameter RITDs. The result demonstrates the potential of Si-based tunnel diodes for low-power memory applications.

One of the key issues in assessing the reliability of power systems. Studies and projects to improve the reliability of the distribution network has mostly been focused on changing the structure of the distribution system or transmission the Executive them even more expensive and is not available. In this work, the development of DG units in distribution networks the presence of these materials ensure that the indicators qabylt distribution network will pay. In this thesis, the main goal of distributed production system effects on the reliability of the system with regard to limitations related parameters such as voltage profiles and losses in the distribution network. Concepts and indicators of the reliability of the network and the ongoing impact of DG units on the reliability of the distribution network will be investigated. Finally, the intelligent ant colony algorithm to determine the optimal location generation units in order to achieve the best reliability indices by including restrictions have been charged. The proposed algorithm is tested on 34 bus IEEE network simulation, simulated and results are compared.