ABSTRACT Various elements and compounds have been studied to fabricate thin film semiconductors for the solar cell applications. Apart from the materials used in the cell fabrication, the performance of solar cell also depends on the technique used and deposition parameters.In this research,the performance of the p-n junction solar cell is improved by depositing thin films at optimized deposition temperature. The optical and electrical behavior of thin films was analyzedundervariedchemical co...
As the future size of phase change random access memory is scaled down, its reliability in data retention, archival life and power consumption is often disturbed by problems such as elemental segregation and compositional variation caused by repetitive phase transformation. These phenomena are closely related to the crystallization kinetics under various environments. The crystallization kinetics at low temperature and slow transition rates of SnxSey thin films have been investigated usi...
Abstract Thin films of SnO2:Al and ZnO: Al were deposited under different deposition parameters. Effect of substrate temperature, Carrier gas pressure, substrate to nozzle distance and doping percentages were investigated to obtain optimum conditions for deposition of p-SnO2:Al for LED applications. Optimized film of SnO2:Al was deposited at temperature of 408 o C, nozzle substrate distance of 4.75 cm, carrier gas pressure of 1.88 bars and aluminium doping atomic percent of 5.37 %. Solid spec...
ABSTRACT The use of local clays for the production of porcelain pin insulators was investigated. Clays from Awo-omama, Ibere and Nsu were used for the study. Test samples were made by varying the compositions of feldspar and quartz needed to form a mouldable plastic body with each clay. The following properties were determined: electrical resistivity, apparent porosity, water absorption, bulk density, linear shrinkage as well as crystalline phases produced after firing. This characterization...
ABSTRACT The recent power sector reform in Nigeria has thrown up enormous challenges in this sector, ranging from the construction of more power stations, construction of new transmission lines and substations. The existing network of 8-plants and 26 bus-bars expanded to the proposed network of 16 generating plants with 49 bus-bars. This network expansion requires reappraisal for power evacuation capabilities, relay systems setting and establishment of stability margins for adverse system fa...
ABSTRACT Transient analysis and performance prediction of passive cooling of buildings using long wave nocturnal radiation in Owerri, Nigeria are presented. Owerri is a typical urban area in southeastern Nigeria lying between latitude 5° 4' and 6° 3' N and longitude 6° 15'and 7° 34' E. The system modeled consists of the room of a building with a radiator panel attached to its roof, water storage tank located inside the room, pump to circulate water through the radiator panel at night and...
ABSTRACT The effects of particle size and particle size distributions of three clay samples, on their modulus of rupture were studied. The three clay samples were collected from natural clay deposits at Nsu; OhiyaUmuahia; and Awo-Omamma all in south eastern Nigeria. The particle size analysis of the clay samples was done by laser diffraction in wet suspension mode and the results disclosed that Awo-Omamma clay has greater proportion of the larger sized particles, (21µm - 25µm) and (25µm -...
ABSTRACT Estimating the gas/VOC emissions from oil and gas producing equipments has been a goal which the industry and regulatory agencies have spent a great deal of study and effort to contend with. This research estimated the flashing losses of gas/VOC emission from conventional atmospheric storage tanks to the atmosphere using Vasquez-Beggs Equation (VBE). Using VBE confirmed observed losses experienced in the industry as is represented in a graph showing the losses. It went further to qu...
ABSTRACT Bio-fuels (Biodiesel and Bio-ethanol fuels) are synthesized from various Nigerian crops (palm(Elaeis Guineensis) wine, raffia(Raffia Vinefera) trunk, sugar cane(Saccharum L), physic nut seed (Jatropha Curcas), castor bean seed(Ricinus Communis), sandbox seed (Hura Crepitans) and African bush mango nut (Dika Nut) (Irvingia Gabonensis)) to serve as alternative fuels for internal combustion engines. The direct base-catalyzed trans-esterification process is employed in the biodiesel pro...
ABSTRACT The suitability of some clay deposits in South Eastern Nigeria (Unwana, Ekebedi, Okigwe and Nsu) as materials for the production of floor tiles was investigated. The clay samples were analyzed using wet classical method to determine their chemical composition. Floor tile test specimens were produced using standard method. The test specimens were tested for physical properties such as compressive strength and porosity at 10500 C and 11500 C temperature levels. The chemical analysis s...
ABSTRACT This work investigates the structural characteristics of soilcrete blocks (lateritecement blocks and laterite-sand-cement blocks) produced with locally available and affordable laterite. Scheffe’s simplex method and Osadebe’s regression theory were used to formulate mathematical models for optimisation of properties of soilcrete blocks which include compressive strength, split tensile strength, shear strength, flexural strength, Poisson’s ratio, modulus of elasticity, shear mo...
ABSTRACT In the manufacturing sector management of the supply chain expenses has been identified as major costs driven problem. For many years, researchers and practitioners have concentrated on the individual processes and entities within the Supply Chain. Recently, however, many companies have realized that important cost savings can be achieved through the reduction of transportation costs throughout their Supply Chain. As companies began realizing the benefits of optimizing transportatio...
ABSTRACT In this study, the potential effects of animal derived organic manure (cow dung, poultry droppings), saw dust and NPK fertilizer on the bioremediation of petroleum hydrocarbon contaminated soil was investigated. The rate of biodegradation was studied for the period of 10 weeks under laboratory conditions. The biodegradation data were fitted to eight models, four of which are based on microbial growth rate and the other four based on order of reaction. Results obtained show that bior...
ABSTRACT This work analysed the current state of power system in Nigeria with emphasis on distribution system using Akwa Ibom Distribution System as a case study. The components of the study system were analyzed. This work adopted the analytical and simulation approach to reliability and stability assessment. Analysing the system the way it is shows that the system was not reliable and stable. The outcome gotten from the base state of the system confirmed this. The results for the current st...
ABSTRACT This project report is an excerpt of the design of a Micro-controller based Access Control Lock system implemented to assist the university with the aid of security personnel in the prompt detection of students who have not completed necessary fees payment and to checkmate the problem of the ever increasing rate of examination impersonation perpetuated by students. The Micro-controller based Access Control Lock system is an automatic software-based system having two major parts; the...