Abstract This thesis discusses the proposal of nonlinear deadbeat control for continuous conduction mode (CCM) boost converter and the experimental verification. First, the nonlinear state equation is derived, and second a nonlinear current reference deadbeat control is proposed. Third, a new nonlinear controller to implement the load disturbance compensation is proposed. Then the simulations using PSIM software and verifications by experiments, it is confirmed that under the conditions of a...
ABSTRACT A Delta Modulated, Buck Type, Three Phase PWM Converter was constructed and tested. The converter is of the current source type and can be used in conjunction with current source inverters. The d.c. current is regulated by proportional feedback control loop. By delta modulation of the voltages across the a.c. terminaIs of the converter, the a.c. source currents are "indirectly" controlled so that the fundamental components remain in a predefined phase with respect to the source volt...
Abstract For decade, thermal contact resistance (TCR) has been measured experimentally. Unfortunately, the database, which should regularly support decision-making on TCR coefficients, seems not to exist. Thus, companies result to using outdated or irrelevant data that limits lifespan of electronics devices, their performance and reliability. This paper mathematically models the problem of TCR between two media (plastic-metal interface) in semi conductors with reference to resistance and the ...
Traditional networking architectures have many significant limitations that must be overcome to meet modern IT requirements. To overcome these limitations; Software Defined Networking (SDN) is taking place as the new networking approach. One of the major issues of traditional networks is that they use static switches that cause poor utilization of the network resources. Another issue is the packet loss and delay in case of switch breakdown. This research proposes an implementation of a ...
ABSTRACT The GP model was developed for production planning in a toothpaste factory. Two objectives were distinguished: minimization of processing cost, and maximization of the capacity utilization of production facilities. Two priority structures were used to explore the trade-off options. When processing cost minimization was assigned the first priority, the utilizations of Processing Plant 1 and Filling Machine 2 were 20.32% and 0.18% respectively. When capacity utilization was assigned fi...
Abstract Grinding is one of the most important fishing operations and it is very useful in our automobile industries. A grinding wheel is made of very small, sharp and hard abrasive particles or grits held together by strong porous bond. The paper presents, a control system for grinding process using neuro -fuzzy technique. The grinding parameters include circurmferentiaI speed of a grinding se ent workpiece velocity and work depth of cut. The maximum grinding temperature is very important ...
INTRODUCTION Excessive water production as result of coning and cresting has been a serious problem in the oil and gas industry. Coning or cresting are used to describe the mechanism underlying the upward movement of water and/or the downward movement of gas into the perforations of a producing well. Efforts have been directed at understanding the mechanism of water coning/cresting in vertical and horizontal wells. These efforts have led to the development of correlations for estimating cri...
Abstract The main objective of this project was to design a cost effective and efficient electronic voting system interfaced with a GSM module. There is need to replace the conventional voting system based on paper in Zimbabwe and many African countries by electronic voting machines which are cheaper, more secure and less cumbersome. Voting is when societies or a particular group of people come up with decisions based on choice and or preferences hence the need for a cheaper, more secure, re...
ABSTRACT Several studies (Rivera and Cary 1997; AFC Consultants International 2011) show that effectiveness and efficiency of extension services have increased where governments have shifted from being the sole provider towards developing more pluralistic kind of extension system. The general objective of this study was to assess involvement and performance of Private Extension Service Providers in Rungwe District. An interview schedule and a note book were used to collect primary data during...
Abstract Joshua Mqabuko Nkomo International Airport was established in 1959 then known as Bulawayo Airport. It is located in the second largest city of Zimbabwe, 25 km to the north of the City of Kings- Bulawayo. JM Nkomo Airport is the second largest airport in Zimbabwe and boasts of two runways which are 2,588 meters long by 45 metres wide and 1,347 metres by 30 metres wide capable of handling wide bodied aircraft such as the Boeing 767. The airport operates 24 hours a day and is equip...
ABSTRACT The traffic situation at many university campuses in developing countries has been a source of concern to both the school authority and the campus populace. This may be largely due to the increasing enrolment level for university admissions since most employers are certificate-biased instead of skill rewarding. The roads are often congested during the day thereby causing inconveniences to everyone. During the "peak period" when vehicular traffic is beyond what the road can contain co...
ABSTRACT The increasing demand for silver nanoparticles has led to the need for new superior methods of synthesis to be developed. In this study, the Allium Ascalonicum plant was used in the plant-mediated synthesis of silver nanoparticles. The phytochemicals of the plant were extracted using seven different solvents with a range of polarities and the methanol/water 50/50 solvent had the highest extraction yield of 63 %. The phytochemical tests showed that the plant is rich in phytochemicals ...
ABSTRACT A green approach was used in the synthesis of silver nanoparticles which is an easy, cheap, eco-friendly and a fast method in achieving stable silver nanoparticles over a long period of time. Plant leaves extract from Parinari Curatellifolia and Vangueria Infausta were used in the synthesis after optimizing different parameters (temperature, silver nitrate concentration and amount of extract. The optimum conditions achieved for the synthesis of silver nanoparticles (AgNPs) using Pari...
ABSTRACT Usage of ergonomically unsuitable classroom chairs and desks promotes bad posture while bad postures affect students’ learning, performance and health. Attention is rarely paid to ergonomic fitness of classroom chair and desk used by primary school pupils in Nigeria up till now. This study investigated classroom furniture status in the Staff School, University of Ibadan, Oyo State, Nigeria and developed an automated procedure for designing ergonomically suitable chair cum desk mode...
ABSTRACT An experimental study was undertaken to evaluate and compare the performances of a local barn and a platform, as storage structures for yam tubers (Dioscorea rotundata poir.) The criteria used for evaluation and comparison were the degree of weight loss during storage, tuber sprouting and rotting of yam tubers during a 17 week storage duration between March and Ju...