ABSTRACT This research work presents the modelling, analysis and control of two topologies of induction generators for wind energy conversion. The two topologies are the shorted stator induction generator (IG) and the doubly-fed induction generator (DFIG). Each of the two topologies employs a wound rotor induction machine and a set of back-to-back converters connected to the rotor of the induction machine, for the energy conversion process. Vector variable models are conventionally deployed f...
ABSTRACT The study was aimed at assessing the impact of network outage on the Value Added Services (VAS) particularly Mobile-Pesa (M-Pesa) among other (VAS) offered by Vodacom network operator in Tanzania. The study was conducted in Ilala municipal in Dar es Salaam Tanzania. The basic parameters used to assess the network availability were Mean Time To Repair (MTTR), Call Setup Success Rate (CSSR) and Total User Outage Time (TUOT). The parameters like the time to get response from the operat...
ABSTRACT A novel low-temperature glycerolysis process for lowering free fatty acid (FFA) in crude jatropha oil for alkali catalyzed transesterification has been developed. The response surface methodology (RSM) based on the central composite design was used to model and optimize the glycerolysis efficiency under three reaction variables namely; reaction time, temperature and glycerol to oil mass ratio. The optimum conditions for the highest glycerolysis efficiency of 98.67% were found to be ...
ABSTRACT Tanzania has been among the earliest countries in Africa to employ Digital Video Broadcast-Terrestrial (DVB-T) System. The deadline for Analogue Switch Off (ASO) was set to be in 2015, but Tanzania decided to have phased switch off since 2010. DVB-T is a new system in Tanzania and hence the extent of quality of the signal needs to be established. This research compares the reception of DVB-T second generation spatial signal strength as offered by Star Media Limited, Agape Associate...
ABSTRACT Hydrolysis of a complex medium (whole-wheat flour) using a mixed culture of Aspergillus. awamori and Aspergillus. oryzae was carried out for the purpose of producing a fermentation medium that can be used to produce industrial chemicals.. The experimentation was carried out in shake flasks as well as in a 10-litre fermenter and the results obtained in all cases indicated that the two microorganisms could cooperate together to hydrolyse both the starch and the protein in wheat flour c...
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; Ohiya- Umuahia; 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...
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 q...
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 pr...
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 10500C and 11500C temperature levels. The chemical analysis ...
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, shea...
ABSTRACT This work evaluated the path losses and strength of received signals of a 3G Network operating at frequency of 2.1GHz in Owerri metropolis using Drive test. There were serious cases of call drops and low Quality of signal (QoS) experienced within some part of the Owerri metropolis. This situation has been burdensome on the side of the network users, as that has made them incur a lot of financial losses and passed through pains. The network providers, on their side, also passed thro...
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 transport...
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 biore...
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 sta...
ABSTRACT The study was aimed at developing mathematical models on the hydraulic performance of Sandbags as Checkdam for erosion control. Pilot studies were carried out at two sites. Site ‘A’ was a natural gully at a location in Ezinihitte-Mbaise, Imo State while site ‘B’ was an artificial channel excavated on the slope of Otamiri River at Federal University of Technology, Owerri. Artificial runoff was simulated into site ‘B’ by pumping water from Otamiri River. Sandbags of ...