LAUTECH Journal of Engineering and Technology (LAUJET)
Not a member yet
571 research outputs found
Sort by
APPLICATION OF STATIC VAR COMPENSATOR FOR VOLTAGE STABILITY ENHANCEMENT AND POWER LOSS REDUCTION IN POWER SYSTEM NETWORKS
Get PDFIn power systems, the mismatch between electricity supply and demand has led to difficulty in maintaining the system voltages within the statutory limit, causing voltage stability problem and consequently poor power transfer. This work is an application of Static Var Compensator (SVC) for voltage stability enhancement and power loss reduction in power system networks using the standard IEEE 6, 14, and 30-bus power networks as case studies. Using MATLAB/PSAT software (version 2.1.9 ‘R2012a’), the Newton-Raphson power flow modeling the steady state conditions of the sample networks was simulated without and with SVC. The simulation results revealed that the voltage profiles of all the considered networks were enhanced and within acceptable limit of after compensation was applied. The system total real power losses of the considered IEEE 6, 14 and 30-bus power networks which were 7.88, 25.76 and 16.05 MW respectively without SVC reduced to 7.08, 24.42 and 15.88 MW respectively with SVC, giving 10.15, 5.20 and 1.06% reduction in total real real power loss respectively for the sample networks. These results showed that SVC as a compensating device is capable of enhancing voltage profile and reducing power loss if incorporated in power system networks
DEVELOPMENT OF AN IMPACT ASSESSMENT ALGORITHM FOR THE ADOPTION OF INFORMATION AND COMMUNICATION TECHNOLOGY IN BASIC EDUCATION USING CROSS-IMPACT METHOD
Get PDFIn many countries, the adoption of Information and Communication Technology (ICT) in basic education has been continuously linked to higher efficiency, productivity, and educational outcomes, including quality of cognitive, creative and innovative thinking. This paper focuses on the development of an impact assessment algorithm for evaluating the adoption of ICT in basic education using Cross-impact method. A questionnaire on adoption of ICT in basic education was designed based on Government Policy (GP), Teacher Competency (TC), Availability of ICT infrastructure (IF), Integration of ICT in school curriculum by Ministry of Education (MC), Student preparedness in adopting ICT in learning process (SC) and Perception of schools’ management in adoption of ICT in schools (MI), which are the six major events considered. The questionnaire was administered to experts in basic education within the selected South-Western states of Nigeria (Oyo, Lagos and Ekiti). Experts’ opinions from the administered questionnaires were quantitatively analysed using descriptive statistic in Statistical Package for Social Sciences. The results obtained from the analysis of questionnaires were used to derive the Initial Probability (InitProb) and generate the Conditional Probability Matrices (CondProbMatrices) for occurrence and non-occurrence of the six events under consideration. The impact assessment algorithm was developed such that its starting instructions would determine the consistence of the InitProb and the CondProbMatrices using the three fundamental laws of probability calculus (Normalization, Product and Addition rules). These are followed by sequential instructions which would determine the occurrence of each event in the CondProbMatrices. Then, through repetitive instructions, each event would be selected at random and its occurrence and non-occurrence would be determined using a random number generator. The last group of instructions would successively determine the impact of each event on other alternative events. Thus, the developed impact assessment algorithm could replace the existing user perspective method of evaluating the adoption of ICT in basic education
ASSESSMENT OF THE MICRO-STRUCTURE OF COMPACTED SOILS USING VARIED COMPACTIVE EFFORTS: A CASE STUDY OF SOME SELECTED AREAS IN PORT HARCOURT, NIGERIA
Get PDFThis research studies the effects of varying British standard heavy and British standard light compactions on the resulting micro-structures of soils using digital microscope. Three soils classified as A-6, A-7-6, and A-2-7 using AASHTO classification system were analysed. The initial properties tests and moisture- dry density relationship were carried out in accordance to British standard 1377 of 1990. The liquid limits ranged from 50.5% to 34.7% using the Casagrande liquid limit apparatus, plasticity index ranged from 22.3% to 12.4% and natural moisture content ranged from 24.3% to 21.2%. The lower the plasticity index the higher the maximum dry density for both degrees of compactions. From the micro-structural analysis, there was evidence of lines of shear at the wet-side of optimum moisture for all compactions and that the presence of these lines is high for soils of lower plasticity index at low compaction energies. At higher compaction effort, there was closer inter-particle aggregation of grains than at lower compaction efforts. The voids at the optimum moisture are smaller compared to those at the extremes of optimum, with voids on the wet-side of optimum larger than those at the dry side of optimum moisture for both compactive efforts. Thus, the micro-structure of the compacted soil revealed that the degree of compaction influences the degree of compactness of gains, the average dimension of voids, and the occurrence of thin lines of shear in their structure
DRYING CHARACTERISTICS OF KEREWA TOMATO UNDER INFRARED DRYING
Get PDF In Drying characteristic for infrared drying of tomato slices were investigated. The drying experiments were carried out using Kerewa local varieties of tomato at five infrared drying power (150, 250, 300, 400 and 500 W) with slice thickness of 10 mm. For all drying powers there was a reduction in moisture content with increased drying time, the drying took place in the falling rate period. The drying time reduced as the infrared heating power increased from 150 to 500W. The diffusivity obtained for the tomato slices were within the range specified for fruits and vegetables with a value of 5.6132 x 10-7 m/s2. Blanched tomato varieties had better rehydration capacities than all unblanched samples
ANALYSIS OF A PIPE RESTING ON WINKLER FOUNDATION AND CONVEYING A NON-NEWTONIAN FLUID
Get PDFFluid conveyance pipes are subject to vibration and the attendant dynamic stresses lead to instability and sometimes failure. The fluid inside the pipe dynamically interacts with the motion of the pipe, therefore, the material properties of the fluid are expected to play important roles on it. This paper analyzed the deformation of a pipe resting on Winkler foundation and conveying a non-Newtonian fluid. Euler-Bernoullis beam and plug flow models are employed in this work. The resulting transverse differential equation was non-dimensionalized, discretized and solved by means of the finite element method. Effects of the fluid materials and other flow conditions were computed and their implications on the pipe integrity analyzed. Natural frequency increased with flow index, Winkler foundation and mass ratios. Critical velocity also increased with Winkler foundation
DEVELOPMENT AND EVALUATION OF AN IMPROVED ELECTRO-MECHANICAL YAM POUNDING MACHINE
Get PDFYam is one of the oldest known recipes to man, which belongs to the class of carbohydrate and has been a part of the African meals for centuries. Pounded yam is generally accepted food prepared from yam tuber using indigenous method or equipment. Replacing such energy in cooking and yam pounding operation became expedient due to many reasons including tedious, laborious and very difficult. Materials to be used for construction of the electro-mechanical pounding machine were sourced locally and three different varieties of yam were used for its performance evaluation. It was observed from the result that the efficiency of the machine is high [98.75% (white yam), 99.70% (yellow yam), and 99.10% (water yam)]. The percentage lump and pounding capacity for white yam, yellow yam and water yam were 1.25, 3.49, 0.90 and 31.71, 29.68, 27.73g/s respectively
OPTIMIZATION STUDIES OF TURBIDITY REMOVAL IN ASA RIVER WATER USING CARICA PAPAYA SEED AS COAGULANT
Get PDFThis study evaluated the potential of Carica papaya Seed (CPS) as a coagulant for water treatment. Surface water samples from Asa River in Ilorin, Kwara State, Nigeria were collected for the study. The trace metal levels were determined using Inductively Coupled Plasma-Mass Spectroscopy (ICP- MS). Treated CPS was obtained from its seed using soxhlet extraction in ethanol .It was then applied for the removal of turbidity and trace metals in the surface water samples. The trace metal results showed the presence of Cu (6.07 ppb), Fe (394.16 ppb), Cr(21.50 ppm), Zn (6.69 ppb) and Ti (13.08 ppb) in the samples of the river water. Optimization studies was carried out for turbidity removal using Full Central Composite Design (FCCD) under the Response Surface Methodology (RSM). The results obtained showed that the maximum turbidity removal of 94.92% was achieved at optimum conditions; coagulant dose (0.47 g), contact time (15.17 min) and agitation speed (791.33 rpm). Also, all the trace metals were found to be below detection limit after contacting with the modified Carica papaya seed
MODELLING A WIND MAP OF NIGERIA TO ASSESS THE UTILIZATION OF WIND AS AN ALTERNETIVE SOURCE OF ENERGY
Get PDFThis paper deals with the feasibility study and efficient utilization of wind energy in Nigeria. Twenty (20) years hourly wind data at 10 m height were collected for 2 stations in each of the 6 geographical zones of Nigeria. The selected stations were: Abeokuta, Osogbo, Calabar, Port Harcourt, Owerri, Enugu, Sokoto, Kano, Jos, Abuja, Maiduguri and Yola. A wind map of Nigeria was modelled using ArcView© Geographical Iinformation System. The study revealed that Jos, Kano and Sokoto have wind energy potential sufficient to generate electrical power that could be connected to the national grid, while Enugu and Maiduguri have enough wind energy potential that could be used to power irrigation devices and other agricultural activities. The establishment of wind power plants for excellent stations such as Jos, Kano and Sokoto for the generation of electricity which could be integrated with the present national grid is recommended
MODELLING THE TIME-DEPENDENT RHEOLOGICAL PROPERTIES OF OIL-IN-WATER EMULSIONS STABILIZED WITH GELATINIZED BAMBARA GROUNDNUT FLOUR
Get PDFThe contribution of emulsion main components to the time-dependent rheological properties of oil in water emulsion stabilized by gelatinized bambara groundnut flour (BGNF) was studied. Sunflower oil-in-water emulsions were prepared and stabilized with gelatinized BGNF. Weltman time-dependent rheological model was used to assess the time-dependent properties of oil-in-water emulsion stabilized with gelatinized BGNF and model’s suitability was judged by the coefficient of determination, R2, root mean square error, RMSE and standard error, SE. All emulsions were thixotropic in nature. The time-dependent behaviour of the emulsions was well described by Weltman model (high R2 and low RMSE and SE values). The mean of parameter A and B values of Weltman model were in the range 11.68 – 315.44 Pa and 0.52 – 25.54 Pa respectively. Both the shear rate of shearing and emulsion main components (BGNF and Sunflower oil (SFO)) greatly influenced the time-dependent model parameters. The results provided the information on the influence of emulsion components and shear rate on rheological properties of BGNF-stabilized emulsions for product and process development
STUDY OF PARAMETRIC EFFECTS OF HOT BATCH EXTRACTION PROCESS OF CASTOR BEAN OIL TOWARD SUSTAINABLE BIODIESEL PRODUCTION
Get PDFThis work investigates the efficacy of hot batch extraction process on castor seeds using Soxhlet extraction apparatus with normal hexane as solvent. The seeds obtained were pretreated by decoction process whereby, both water and protein content therein were drastically reduced. The effect of the yield on duration of extraction, solvent volume and mass were carried out by adopting a central composite design of response surface methodology and based on the statistical analysis and optimization of various operating variables using a statistical Design Expert software version 6.0.8 (STAT-EASE Inc., Minneapolis, USA) A second order quadratic model was developed in order to correlate the three variables to the response. The optimum conditions for hot batch extraction process of crude castor oil were found to be 150 minutes period of time, 160 ml of solvent volume and 99.9% of mass. At the calculated optimum conditions, the yield was 80.7% at the point desirability of 99.2%. Acid value of 0.45mgKOH/g and calculated 0.23% value of free fatty acid were found to be within the standard range for biodiesel production. The mathematical model developed was found to adequately describe the compatibility with the data predicted and accurate statistical prediction of the optimum yield conditions and the quality of crude castor oil were established