Journal of Advances in Science and Engineering
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CANFIS based DSTATCOM modelling for solving power quality problems
Get PDFDevolution of the power grid into smart grid was necessitated by the proliferation of sensitive load profiles into the system, as well as incessant environmental challenges. These two factors culminated into aggravated disturbances that cause serious havoc along the entire system structure. The traditional proportional-plus-integral-plus-derivative (PID) solution offered by the distribution synchronous compensator (DSTATCOM) could no longer hold. As such, this paper proposes some soft-computing framework for redesigning DSTATCOM to automatically deal with power quality (PQ) problems in smart distribution grids. A recipe of artificial neural network (ANN) and coactive neuro-fuzzy inference systems (CANFIS) was fabricated for the objective. The system was modelled, simulated, and validated in MATLAB/Simulink SimPowerSystems environment. The performance of the CANFIS against adaptive neuro-fuzzy inference systems (ANFIS), ANN and fuzzy logic controllers’ algorithms proved superior in handling PQ issues like voltage sag, voltage swell and harmonics
Development of a horizontal three bladed windmill with vortex tubes
Get PDFResearchers have been continuously searching for the most readily available means of producing electricity without any negative effect on the environment. Renewable source of energy like solar energy, hydro electric energy, biomass and wind energy has been considered as the alternative. Wind energy among others is rated the best renewable sources of energy because it’s level of environmental friendliness. In this paper, a horizontal windmill was designed, fabricated and its performance evaluated with two types of vortices and without a vortex. The component parts of the mills are towel, blades, shafts, base, tail vain and vortex. During the design of the windmill, consideration was given to the size, area of the blade and the blade material that produce maximum speed. The performance evaluation was carried out to compare the performance of the mill with the solid vortex, gap vortex and without vortex. The result of the evaluation reflects that the solid vortices have the highest wind speed irrespective of time of the day and with an optimum wind speed of 5.04 m/s. Also, the wind mill performed at a higher efficiency with the vortex compare to when it was running without vortex.  
Spheroidal graphite iron production of furnace roof hangers
Get PDFThe wire rod mill of the Ajaokuta Steel Company Limited produces coils, wire rods and re-bars of different sizes. Without the furnace hangers, it will be difficult for the mill to continue to operate. This paper describes the production of furnace roof hangers that are required for re-heating furnace using the spheroidal graphite iron (SGI), highlighting the sand-casting process, charge calculation, and the chemical compositions. The facilities within the foundry shop of the steel company are used to produce furnace roof hangers. The available materials used for the casting of the hangers are the pig iron, scrap ends, foundry returns and magnesium. The process of production was performed through the reheating furnace for the heating of 120 m x 120 m x 120 m billets. One ton induction furnace of low frequency was used as the melting vessel. Also, 6 kg of magnesium was introduced in the ladle before the liquid metal was teemed into it. A Spectro analytical instrument was used to determine the chemical compositions of the materials before and after the casting processes. The analysis of the chemical compositions of produced sample of SGI are presented and discussed
Determination of best-fit isotherm model for the sorption of Lead (II) and Manganese (II) ions onto acid-activated shale using selected non-linear error functions
Get PDFThe focus of this research is to apply the selected error function equation to establish the equilibrium isotherm model that best describes the adsorption of Pb2+ and Mn2+ onto acid-activated shale. Data collected from the batch experiment were analyzed using selected isotherm models (Langmuir, Freundlich, Temkin, Dubinin-Radushkevich, Sips and Redlich-Peterson). To compute the isotherm parameters used in choosing the best-fit isotherm model, selected non-linear error functions, namely, error sum of the square, normalized standard deviation, hybrid error function, root mean square error and Marquardt’s percent standard deviation were employed. From the scanning electron microscope results, it was observed that the surface characteristics of the shale change considerably with calcination and acid treatment but the acid-treated shale shows better uneven porous surface characteristics. Error function computation shows that the Dubinin-Radushkevich isotherm model had the least sum of normalized error of 0.3623 for Pb2+ adsorption and 0.5465 for Mn2+ adsorption; hence, it was selected as the best isotherm model for explaining the sorption of Pb(II) and Mn(II) ions unto acid-activated shale
Analysis of critical imposed load of plate using variational calculus
Get PDFThis work studied the critical load analysis of rectangular plates, carrying uniformly distributed loads utilizing direct variational energy calculus. The aim of this study is to establish the techniques for calculating the critical lateral imposed loads of the plate before deflection attains the specified maximum threshold, qiw as well as its corresponding critical lateral imposed load before the plate reaches an elastic yield point. The formulated potential energy by the static elastic theory of the plate was minimized to get the shear deformation and coefficient of deflection. The plates under consideration are clamped at the first and second edges, free of support at the third edge and simply supported at the fourth edge (CCFS). From the numerical analysis obtained, it is found that the critical lateral imposed loads (qiw and qip) increase as the thickness (t) of plate increases, and decrease as the length to width ratio increases. This suggests that as the thickness increases, the allowable deflection improves the safety of the plate, whereas an increase in the span (length) of the plate increases the failure tendency of the plate structure
Emission dispersion modeling and geospatial analysis of vehicular emissions in some parts of Benin City, Nigeria
Get PDFOver the years, decline in air quality has been connected to the growing rate of urbanization and increasing number of vehicles on the roads. Most of the pollutants emitted from vehicular activities have been observed to have adverse effects on individuals as well as the atmosphere. Although, the focus of this study is to develop an emission dispersion model to predict the concentration of specific air pollutants with distance, the application of geostatistical technique such as Kriging interpolation to study the spatial distribution of pollutants from vehicular emissions around the study area was also exemplified. Seven (7) georeferenced points, namely, Ugbowo main gate, Ekosodin junction, Agen junction, Super D junction, Nitel junction, Okhunmwun junction and Oluku market junction were used for data collection. Pollutants from vehicular emissions, namely, nitrogen dioxide (NO2), carbon monoxide (CO) including the total radiation were monitored in the morning and evening for a period of 35 days (7th July to 12th August 2020) with the aid of portable toxic gas monitors and radiation alert meters. Other parameters of interest, which were also measured include maximum temperature and wind speed using infra-red thermometers and portable anemometer respectively. To ascertain the quality of the data, selected preliminary analysis, namely, test of normality, test of homogeneity, outlier detection and reliability test were done. Result of the study showed a high concentration of NO2, CO and total radiation around Ugbowo main gate and Okhunmwun community and environs especially during the peak hours of evening (5.0 p.m. – 6.0 p.m.) when the traffic load is high
Estimated billing system is the bane of grid electric power supply and development in Nigeria: An empirical analysis
Get PDFThe estimated billing system for electricity was introduced in Nigeria by the Nigerian Electricity Regulatory Commission (NERC) in 2012 for billing customers without meters or with faulty or inaccessible meters. But instead of following the guidelines and formula provided by NERC for the estimation, the electricity Distribution Companies (DisCos) resorted to billing these customers arbitrarily and frustrated efforts by NERC to ensure the proper metering of electricity consumers. This research evaluates the incentive, which makes the DisCos in Nigeria prefer the estimating billing system to a much more efficient smart prepaid metering system. To carry out the research, four Enugu Electricity Distribution Company (EEDC) customers were selected. The estimated bills of these customers, which they received before they got smart prepaid meters, were compared with their prepaid meter bills for an equal period. EEDC was found to be over-billing these customers under the estimated billing system by a yearly average per customer of 64,901.67 Nigerian Naira (170.79 USD)
Statistical prediction of the drying behavior of blanched ginger rhizomes
Get PDFARS-680 environmental chamber was employed in this study to determine the drying behavior of sliced ginger rhizomes. Blanched and unblanched treated ginger rhizomes were considered at drying temperature of 40 °C for a period of 2 – 24 h. Linear and non-linear regression analyses were employed to establish the correlation that exits between the drying time and the moisture ratio. Correlation analysis, root mean square error (RMSE) and standard error of estimate (SEE) analysis were chosen in selecting the best thin layer drying models. Higher values of determination coefficient (R2) show goodness of fit and lower values of SEE implies better correlation; and RMSE values were also utilized in determining the goodness of fit. The drying data of the variously treated ginger samples were fitted into the twelve thin layer drying models and the data obtained were fitted by multiple non-linear regression technique. Blanched treated sample exhibited a better drying behavior losing about 82.87 % moisture content compared with unbleached sample that lost about 62.03 % of moisture content. Two-term exponential drying model proved to be the most suitable model for predicting the drying behavior of ginger rhizome. The model exhibited high R2 values of 0.9349-0.9792 (which are close to unity) for both blanched and unbleached samples. Also, it recorded relatively low values of RMSE and SEE (3.6865 - 2.0896 and 3.6564-2.7486 respectively) for both treatments.  
Extraction of the pulse width and pulse repetition period of linear FM radar signal using time-frequency analysis
Get PDFA common technique used by military to realize low probability of intercept (LPI) is linear frequency modulation (LFM) in the field of electronic intelligence (ELINT). This paper estimates the pulse width (PW) and the pulse repetition period (PRP) of LFM signal using instantaneous powers. The instantaneous powers were obtained either using time-marginal or power maxima approximated from a modified version of the Wigner-Ville distribution (WVD). The instantaneous power was also gotten directly from the signal by multiplication with its conjugate. Measurement was then carried out when the instantaneous power is ‘ON’ (the PW) and when it is ‘OFF’ (the PRP) at carefully selected thresholds. Thereafter, the mWVD-based algorithm was tested in the presence of additive white Gaussian noise (AWGN) at various signal-to-noise ratios. Results obtained during the test showed that the time marginal method emerged the best with minimum signal-to-noise ratio (SNR) of -5dB followed closely by the direct method with minimum SNR of -1dB at different thresholds. The results show that the proposed algorithm based on this modified WVD can be deployed in the practical field to determine radar’s performance and functio
Evaluation of net radiation using the autoregressive models with higher orders over Nigeria
Get PDFIn this study, monthly surface net radiation data were collected from the Nigeria Meteorological Agency, Lagos covering a duration of 31 years (1983- 2013) spatially distributed across the four climatic regions: Semi-Arid (SAR), Sub-humid Dry (SHD), Sub-humid Humid (SHH) and Humid (HUM) regions. The net radiation was evaluated using different forms of Auto-Regressive models – AR {p} where p is the number of orders of the auto-regressive. The analysis showed that AR {4} performed best in all the regions and stations investigated. Regionally, AR {4} has maximum values of coefficient of determination of 0.8127 in HUM, 0.7876 in SHH, 0.5765 in SHD and 0.7973 in SAR regions. It can be concluded that the higher the order of auto-regressive models, the more accurate estimation of net radiation it will give irrespective of location in Nigeria