ABSTRACT The requirements of a standard 3-phase Induction Motor driven by a Voltage Source Inverter studied. A ful I 3-phase Variable Speed Drive and its controller have been designed, constructed and tested. Gate Turn-Off Thyristors used as the main switching elements in the Inverter stage of the Drive. The drive requirements of GTO's are studied in detai 1.
Abstract Selection of optimum machining parameters is an essential factor in process planning for efficient metal cutting operations. In this study, an artificial neural network- based tool wear predictive model and a genetic algorithm-based optimization model were developed to determine the optimum cutting parameters for turning NST 37.2 steel with uncoated carbide cutting inserts. Multi-layer, feed-forare, back -propagation network was used in predictive model, while maximum metal removal r...
ABSTRACT Crop production is influenced by on-site soil moisture availability and application of water conservation methods for dry areas. This research explored the interactive effects of spate irrigation as an application method and the soil moisture conservation techniques. The objective of this research was to analyze the effectiveness of soil moisture conservation techniques and its correlation to water productivity for sorghum production under spate irrigation. The soil water holding ca...
ABSTRACT The e-beam stimulated reaction, CdCI2(s) ---> Cd (s) + CI(g), has been studied in casmium chloride thin films between 303 and 483 K using 2-keV electrons. The dose required to make 90-nm-deep holes at 483 K is 3x10-3 C cm -2. Extrapolated dosing levels of 6x10-5 C cm -2 are expected. The use of CdCI2 as a positive-type electron resist in a new scheme is proposed. A working model, useful for considering the e-beam stimulated decomposition energetics and mechanism is briefly discussed.
Abstract Several procedures have been proposed to overcome various challenges of product-content analysis after manufacturing and downstream automatad recycling pmcesws. These procedures have been restricted by factors such as the inabiiity to determine exactly the physical state of the hidden pm of End-of-Life products. This inhibition among others has rresldted into an explosion of solutions by researchers. This paper presents the initial investigations in the development of imaging softwa...
ABSTRACT Tool wear measurement is of great concern in machining industry, as it affects the surface qualities, dimensional accuracy and production costs of the machined components. The orthodox methods of measuring tool wear are time consuming and limited in accuracy and application. In this study, machine vision system based on digital image processing was developed for measurement of tool wear. The basic components of the system are: a charge coupled device (CCD) camera, PC, Microsoft Wind...
ABSTRACT Engineering structures subjected to dynamic loading exhibit vibration motions. These vibrations induce accelerations on the structures and their component parts. The accelerations in turn generate inertia forces that propagate the vibrations and significantly affect the response of the structures and their components parts to external loading. This cyclic cause and effect situation result in randomly oriented and time-dependent displacements as the basic response criteria of s...
ABSTRACT Energy benchmarking and carbon footprint reduction opportunities in Portland cement manufacturing processes in Nigeria are presented. Life Cycle Assessment (LCA) is used to estimate the environmental impact of three cement manufacturing processes in Nigeria. The energy consumption of the cement manufacturing processes are evaluated using energy Benchmarking and Energy Savings Tool for cement (BEST-Cement). BEST-Cement evaluates and compares the energy consumption of the cement manuf...
ABSTRACT In this thesis, a current source inverter fed squirrel cage induction motor drive at constant air gap flux is presented. The drive scheme is conceived to take advantage of the short circuit withstand capability of the current source inverter and the ruggedness (even under harsh conditions) of the squirrel cage induction motor. The variable inverter input dc link current is derivable from either a controlled ac to dc converter or a controlled dc to dc converter. The constant motor air...
ABSTRACT The paper presents an analysis of beams on non-homogeneous elastic foundation, where the deformation is partly localized and partly continuous. The soil was modeled to be in layers, in which two layers within the soil strata were considered. The different layers of the soil have their respective sub-grade modulus k, and the entire foundation is resting on a rigid base. The formulation was achieved by imbedding a beam of known bending rigidity within the layers of the foundation. The...
ABSTRACT The major source of water in EMENE, the study area is rain, streams and well water. Waste management has been a problem in Nigeria and so many developing nations. Most organic pollutant and pollute our underground waters. In this research, three wells were reported polluted in the compound of Adedoyin school of preliminary studies, this research was carried out to know if pollution was as a result of a dump site found inside the compound. Well B was more closer to the dump site, fol...
ABSTRACT Interior Permanent Magnet (IPM) motor is widely used for many industrial applications and has relatively high torque ripple generated by reluctance torque. Since the configuration of the stator has great influence on reluctance torque, different stator configuration is necessary to improve the torque performance of IPM motor. Natural variable modeling and performance comparison of Interior Permanent Magnet Motor with Concentrated winding (CW), Short pitched and Full pitched distribu...
Abstract Hydrological models are useful tools for prediction and understanding of hydrological phenomena which underpin watershed resources utilization. A watershed model simulates hydrological processes in a more holistic manner across the entire watershed area. Most watershed models are fairly complex; interactions among watershed hydrological components are essentially nonlinear and take place on a wide range of temporal and spatial scales. The Watershed Resources Management (WRM) model w...
ABSTRACT Construction industry has complexity in it nature because it contains large number of parties such as clients, consultants and contractors. The factors that influence construction management practice differ from country to country, due to prevailing conditions. The objective of this project is to identify factors that influence construction management practice in Nigeria construction industry and elicit perceptions/ranking of the severity using relative importance index of the vario...
ABSTRACT The greatest challenge in the agriculture is to produce more food with low quantity of water. The challenge facing tomato farmers in Njoro Sub - County is the unfavourable conditions for tomato growth which includes very low rainfall during the seasonal dry periods. However, there is limited information on optimum water management practices, or deficit irrigation that would increase tomato crop yield and additionally improve the tomato quality when drip irrigation is used. The objec...