Advanced Materials Research Vols. 62-64

Abstract: Apart from woodwork, brickwork, all other formworks are of metalwork. Thus engineering devices, equipment, machineries and infrastructures are made possible with the use of welding machines, be it carbide or arc – welding type. In Nigeria, where the cost of imported goods rises astronomically in accordance with the foreign exchange rates, the need to fabricate this very important equipment became of important necessity. In this paper, a single-phase 6KVA, 240VAC/30-70 VDC electric arc welding machine was designed and constructed using locally available materials. The different operating current required, arcing time, the heat generated by the arc, the minimum arc gap, the fluxite coated electrode, oxidation of the molten materials by the surrounding air where some of the designed parameters that determined the auto-transformer specific magnetic loading and specific electric loading. Cooling medium, integral switch, the rectifier circuits and the tanking of the transformer designed determined the equipment production. The locally fabricated AC/DC air cooled electric arc welding machine capable of withstanding 200A, when subjected to insulation resistance test, no – load test, short circuit test and on-load test to ascertain its performance characteristics were very satisfactory.

Abstract: This paper presents the comparative analysis of the measurement of static electric field within and outside the test location in Zaria, Nigeria, based on the measurement carried out using a data acquisition system, interfaced with a digital electrostatic field strength meter (model 257D). The acquired electric field data are captured by a computer using the Microsoft Office Excel Program. The focus of the analysis is determining the effect of environmental factors such as temperature, pressure and relative humidity on the static electric field during the harmattan (March) and non-harmattan period (April – May). The plots of the average electric field against the variation of the environmental factors were used as the qualitative analytical tools and conclusion was drawn to the fact that the relative variation in the measurement of the electric field within and outside the test location is averagely 0.06KV/cm and dependent on the environmental factors.

Abstract: This paper examines the various reforms carried out in the Nigerian power sector between the year 1999 and 2007 and its impact on the life of the average citizens. Efforts were made to review relevant literatures, questionnaires were administered and forty-nine responses were received and the result was analyzed through the use of simple percentages and correlation coefficient. The correlation coefficient method, r (the product moment of the correlation was negative and of magnitude -1, implying a perfect correlation in the negative direction (deregulations and reforms are not improving the power sector of Nigeria yet). The research hypothesis, HR, stated that the deregulation and reforms did not evidently improve the power sector. It was recommended that the government should continue the rehabilitation of the various power systems in a guided manner to allow a core Nigerian investor, consider alternative sources of energy like solar, tide, biomass, wind.

Abstract: This paper discusses the design and construction of a human body resistance and temperature measurement device. The device measures the human body temperature and resistance when the sensing probes are placed in contact with the human skin. The design analysis was based on simple electronic circuit theories leading to specification and choice of components used for the construction of the system. After the construction and testing with various individuals the human body resistance and temperature was found to be within the ranges of 1KΩ to 210KΩ and 36.10C to 37.50C respectively. The paper discuses the various effect of current on the human body and their implication. The system can be adapted to various fields such as bio-technology, security (lie detector), safety equipment in industries and companies to determine insulation.

Abstract: This work investigates the microwave link degradation due to atmospheric conditions on the Akure-Owo Digital Microwave Link. Microwave line of sight measurements were carried out between January and December 2005 with a data acquisition software (PROCOMM PLUS SOFTWARE). The data collected were analyzed using MATLAB 7.0 SOFTWARE program to determine the months of the year that has the highest degradation due to atmospheric conditions and also the months of the year that has the highest bit error rates. The result showed that the months of January, June, July, August and September have the worst signal degradation of -0.97dbm, -2.0dbm, -3.97dbm, -3.97dbm, -1.97dbm. respectively. The result also showed that the bit error rates are good and acceptable throughout the months of the year. A model equation was developed to predict the signal strength received and the bit error rate in the microwave link investigated, when atmospheric conditions are taken into consideration. The results of the predicted model were validated by field data and the results obtained showed an error of -0.2% for the received signal level and zero error for the bit error rate which means that the developed model equations can be used to accurately predict the link degradation parameters.

Abstract: The success of wireless local area networks (WLANs) has led to an intense interest among wireless engineers in understanding and predicting radio propagation characteristics within buildings. This paper present radio signal propagation measurement and modeling at 2.4GHz, within a building in the Faculty of Engineering, University of Benin. A base station built around SENAO access point, and a PA24 flat panel directional antenna of 19dBi gain and 17.50 beam-widths was setup for the experimentation. Signals were monitored from the fixed BS using LINKSYS, and NET STUMBLER version 4.0 software run on a Laptop. In this report, the effect of multi-path and delay spread was not considered. The result of the investigation revealed a significant attenuation of the radio signal within the small distance. A path loss exponent of 7.8 to 8.9 on the ground floor, and 2.9 to 5.2 for the 2nd floor were obtained for the period of investigation.

Abstract: This paper focuses on the need and procedure for the planning of electrical engineering infrastructure for any district/community in order to enhance reliability and efficiency of power supply to consumers. Almost all the towns/cities in Nigeria are unplanned and this has resulted in haphazard approach to Electricity Network Planning and implementation. A detailed theory, methodology and technical considerations, in compliance with both National and International standards are discussed in this paper. A proposed University campus was used to demonstrate the procedures involved in electricity network planning in order to achieve an efficient power supply. This involves the electric power supply, design concepts, load estimates and analysis, network distribution/equipment and sizing of cables and electrical panels taking into account the various modes of distribution. This paper also drew a simple analogy between Benin City and the Federal Capital Territory, Abuja, to illustrate the objective of the paper while highlighting the merits associated with planned electrical engineering infrastructure and suggested the ways to remedy the unplanned networks in Nigeria.

Abstract: Autonomous Vehicular Navigation poses interesting challenges and, Automatically Guided Vehicle (AGV) Path Tracking presents an important notion in real-time Mechatronics applications. This paper describes the design of a Path Tracking Automatically Guided Vehicle that is capable of autonomously navigating a predefined path on a level navigating plane and, the designed AGV successfully completed a 3.42 meter test course in precisely 2 minutes 16 seconds. The AGV comprises a PIC16F84A microcontroller utilized as an embedded controller and, an array of Infrared reflective optical sensors to enable path detection and tracking. Among the primary objectives of the design that were achieved was to design the low-cost mobile robot from component parts sourced locally, from within Nigeria.

Abstract: An automatic transfer system (ATS) was developed to monitor the a.c. voltage coming from Power Holding Company of Nigeria (PHCN) line for power failure conditions. Upon detection of an outage for a predetermined period of time, the standby generator is started, once is up to speed, the load is transferred from the PHCN line to the local Generator. This ATS is capable of electrically monitoring fuel level, oil level, Battery strength, next maintenance schedule and then start or stop the unmanned Generator from the computer system located in the comfort of homes or offices outside the Generator site. In this paper therefore, an Automatic Transfer System (ATS) for Power Generator is designed to improve the operation and maintenance of power generators. The ATS which includes both hardware and software module, provides a functionality that allows a power generator to be controlled and monitored from a remote location

Abstract: Two different size-grained soils were subjected to column experiments with a hydraulic loading representing two years’ rainfall. Leachates were collected and analysed for pH and temperature and for eight trace metals, namely; Iron (Fe), Copper (Cu), Chromium (Cr), Nickel (Ni), Lead (Pb), Manganese (Mn), Zinc (Zn), and Silica (Si). The analysis was conducted using an inductively coupled plasma (ICP) method of spectrometry. The results show different extractable metal concentrations from the two soil samples.