ABSTRACT Thin film semiconductors of SnxSey and aluminum doped ZnO are potential candidates for the development of future generation improved efficiency and low cost solar cell devices. This is due to their high absorption co-efficient and good optical properties in the visible region of the solar spectrum. Optical characterization of the two thin films under varied composition and deposition conditions was done by optimizing them for an improved solar cell. Deposition of both SnxSey and ZnO:...
ABSTRACT The use of solar energy for cooking offers an alternative source of energy to the high cost of petroleum products and the diminishing wood fuel products for cooking and heating applications. An effective solar cooker is the one that can be used throughout the day and in the evening when there is no sunshine. Most areas in Kenya can be considered as a high potential solar energy area because Kenya is located on the equator. Most of the solar cooker designs do not have thermal storage...
ABSTRACT This study was concerned with the challenges facing secondary schools‟ teachers and students in the use of instructional technologies. The rationale was based on the view that properly designed, learning materials inspired by instructional technology and delivered by technology add value to a teaching environment on which contact hours are limited. This is because the curriculum needs academic standards and the development of digital age skills for the 21st century learners. The li...
ABSTRACT The raise in industrial development in catchments has left no option but to discharge industrial effluents into water bodiessuch as sea, rivers and streams. Discharging of industrial effluents into water bodies if not done with care through effluent pre-treatment and assurance of complience with allowable standards can lead to water quality impairment. This study was carried outto assess the effects of the effluents from Bonite bottlers and China paper industries on water quality in ...
ABSTRACT Air pollution is a major factor of consideration in the evaluation of quality of life and as an environmental issue in urban areas. Among the urban air pollutants, carbon monoxide (CO) is one of the most prevalent and having serious health as well as environmental effects. The availability of accurate information about its concentrations, variations and location is vital in the determination of urban air pollution. A number of devices for carbon monoxide monitoring have been designed...
ABSTRACT Indium Selenide (InxSey) has shown great advantages over the conventionally used Ge2Sb2Te5 as a phase change memory material (PCM). It has been established that the electrical resistivity of Indium-Selenide based memory cell can be varied by a factor of 105 related with the degree of crystallization as compared with 103 for Ge2Sb2Te5. It is this wider change of electrical resistivity and higher electrical resistivity that has attracted great attention to Indium-Selenide based phase ...
ABSTRACT Thin films for solar cell application have been found to be unstable when used in extreme weather conditions. Therefore there is a quest for the study of effects on light soaking and exposure to outdoor conditions on SnxSey/ZnO:Sn solar cell. A p-n junction thin film solar cell was prepared using SnSe as the absorber layer and ZnO:Sn as a window layer. Tin selenide thin films were prepared at different ratios using pure tin pellets and selenium powder. The glass tube containing mixe...
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...