Buckling of framed and plated structures has been a great concern that researchers try to handle over the past decades. In most developing nations such as ours, fewer or no experimental trials are available to obtain requisite information for the proper understanding of this phenomenon. It is on this premise that an attempt is made to conduct a preliminary study to numerically evaluate the buckling of steel columns under eccentric loadings. To achieve this, a static, linear perturbation analysis was initially performed on a pin-ended steel column using the subspace Eigen solver for the different buckled mode shapes to illustrate the likely behaviour of the column when subjected to compressive actions. Then, the static, general analysis was conducted with the column subjected to varying magnitudes of eccentric loadings. It was required to determine the load level at which the column would fail when subjected to these eccentric loadings. Consequently, a base load value equivalent to 10 % of Euler's critical buckling load was used. This load value was thereafter increased by 20 % in sequence. It was discovered that 10 % of the Euler's critical buckling load can alter the stiffness of the column when loaded eccentrically. It was further observed that the steel column finally failed at a load greater than 20 % of the Euler's critical buckling load and 40.1% of Rankine's critical buckling load. This is because the permissible deflection for unbraced columns may be taken as the quotient of effective length of column to 250, which translates to 13.8 mm. Therefore, the maximum deflection of 14.72 mm reached by applying an eccentric load of 514 kN exceeds the allowable limit of 13.8 mm.
{"title":"Numerical analysis of steel columns subject to eccentric loadings","authors":"E. Ufuah","doi":"10.37121/jase.v4i1.137","DOIUrl":"https://doi.org/10.37121/jase.v4i1.137","url":null,"abstract":"Buckling of framed and plated structures has been a great concern that researchers try to handle over the past decades. In most developing nations such as ours, fewer or no experimental trials are available to obtain requisite information for the proper understanding of this phenomenon. It is on this premise that an attempt is made to conduct a preliminary study to numerically evaluate the buckling of steel columns under eccentric loadings. To achieve this, a static, linear perturbation analysis was initially performed on a pin-ended steel column using the subspace Eigen solver for the different buckled mode shapes to illustrate the likely behaviour of the column when subjected to compressive actions. Then, the static, general analysis was conducted with the column subjected to varying magnitudes of eccentric loadings. It was required to determine the load level at which the column would fail when subjected to these eccentric loadings. Consequently, a base load value equivalent to 10 % of Euler's critical buckling load was used. This load value was thereafter increased by 20 % in sequence. It was discovered that 10 % of the Euler's critical buckling load can alter the stiffness of the column when loaded eccentrically. It was further observed that the steel column finally failed at a load greater than 20 % of the Euler's critical buckling load and 40.1% of Rankine's critical buckling load. This is because the permissible deflection for unbraced columns may be taken as the quotient of effective length of column to 250, which translates to 13.8 mm. Therefore, the maximum deflection of 14.72 mm reached by applying an eccentric load of 514 kN exceeds the allowable limit of 13.8 mm.","PeriodicalId":92218,"journal":{"name":"International journal of advances in science, engineering and technology","volume":"26 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-01-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80414139","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Over 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.
{"title":"Emission dispersion modeling and geospatial analysis of vehicular emissions in some parts of Benin City, Nigeria","authors":"I. Ilaboya, E. A. Otuaro","doi":"10.37121/jase.v4i1.143","DOIUrl":"https://doi.org/10.37121/jase.v4i1.143","url":null,"abstract":"Over 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.","PeriodicalId":92218,"journal":{"name":"International journal of advances in science, engineering and technology","volume":"24 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-01-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89710192","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This 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.
{"title":"Analysis of critical imposed load of plate using variational calculus","authors":"F. Onyeka, T. E. Okeke","doi":"10.37121/jase.v4i1.125","DOIUrl":"https://doi.org/10.37121/jase.v4i1.125","url":null,"abstract":"This 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.","PeriodicalId":92218,"journal":{"name":"International journal of advances in science, engineering and technology","volume":"11 8 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-01-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83758057","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
C. Ocheri, A. D. Omah, C. N. Mbah, R. E. Njoku, N. A. Urama, C. W. Onyia, J. Ezeanyanwu, S. M. Adam
The 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.
{"title":"Spheroidal graphite iron production of furnace roof hangers","authors":"C. Ocheri, A. D. Omah, C. N. Mbah, R. E. Njoku, N. A. Urama, C. W. Onyia, J. Ezeanyanwu, S. M. Adam","doi":"10.37121/jase.v4i1.107","DOIUrl":"https://doi.org/10.37121/jase.v4i1.107","url":null,"abstract":"The 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.","PeriodicalId":92218,"journal":{"name":"International journal of advances in science, engineering and technology","volume":"17 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-01-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78876422","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In this paper, the optimal placement of Unified Power Flow Controllers (UPFC) in a large-scale transmission network in order to improve the loadability margin was considered. In other to achieve this aim, the Line Stability Factor (LQP) as a technique for the optimal location of UPFC in the IEEE 14-bus network and 56-bus Nigerian national grid was adopted. The power injection model for the UPFC was employed to secure improvements in the loading margin of the IEEE 14-bus network and 56-bus Nigerian national grid system. Continuation power flow was used to assess the effect of UPFC on the loadability margin. Steady-state simulations using Power System Analysis Toolbox (PSAT) on MATLAB was applied to determine the effectiveness of placing UPFC between bus 13 and bus 14 in the IEEE 14-bus network and between bus 44 (Ikot-Ekpene) and bus 56 (Odukpani) in the 56-bus Nigerian national grid system. The results showed that the loadability margin increased by 8.52 % after UPFC was optimally placed in the IEEE 14-bus network and increased by 195.5 % after UPFC was optimally placed in the 56-bus Nigerian national grid system. Thus, these enhance the voltage stability of both network and utilizing the network efficiently.
{"title":"Enhancement of voltage stability in an interconnected network using unified power flow controller","authors":"I. A. Araga, A. Airoboman","doi":"10.37121/jase.v4i1.141","DOIUrl":"https://doi.org/10.37121/jase.v4i1.141","url":null,"abstract":"In this paper, the optimal placement of Unified Power Flow Controllers (UPFC) in a large-scale transmission network in order to improve the loadability margin was considered. In other to achieve this aim, the Line Stability Factor (LQP) as a technique for the optimal location of UPFC in the IEEE 14-bus network and 56-bus Nigerian national grid was adopted. The power injection model for the UPFC was employed to secure improvements in the loading margin of the IEEE 14-bus network and 56-bus Nigerian national grid system. Continuation power flow was used to assess the effect of UPFC on the loadability margin. Steady-state simulations using Power System Analysis Toolbox (PSAT) on MATLAB was applied to determine the effectiveness of placing UPFC between bus 13 and bus 14 in the IEEE 14-bus network and between bus 44 (Ikot-Ekpene) and bus 56 (Odukpani) in the 56-bus Nigerian national grid system. The results showed that the loadability margin increased by 8.52 % after UPFC was optimally placed in the IEEE 14-bus network and increased by 195.5 % after UPFC was optimally placed in the 56-bus Nigerian national grid system. Thus, these enhance the voltage stability of both network and utilizing the network efficiently.","PeriodicalId":92218,"journal":{"name":"International journal of advances in science, engineering and technology","volume":"18 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-01-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80825896","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Anthony Chibuike Ohajianya, E. C. Mbamala, C. Amakom, C. Akujor
The major cause of deterioration in lead-acid batteries is sulfation. There are patents on the use of high-frequency pulse desulfators to desulfate lead-acid batteries. Also, many products available in the market worldwide claim to use this technique to effectively desulfate lead-acid batteries that deteriorate due to sulfation. But there are little or no systematic studies to evaluate the performance of these products to know whether they do what their manufacturers claim. This research, therefore, aims at empirically evaluating one of such products. Four fully charged 100 Ampere-hour Valve Regulated Lead-Acid Gel batteries were discharged with an electronic-load battery discharger to ascertain their capacities. Thereafter, a high-frequency pulse desulfator was connected to desulfate the battery bank consisting of the four batteries. The battery bank was connected to be charged at the same time by a photovoltaic system. The desulfation experiment lasted for ten weeks but the batteries were tested to know their capacities after two, six, and ten weeks. The results show that the desulfation device works in desulfating lead-acid batteries as there are different degrees of improvement on the capacity of all the batteries. The percentage improvement in the capacity of the batteries is 89.5%, 75.9%, 1.6% and 1.4%, for batteries 1, 2, 3 and 4, respectively.
{"title":"An empirical investigation of lead-acid battery desulfation using a high-frequency pulse desulfator","authors":"Anthony Chibuike Ohajianya, E. C. Mbamala, C. Amakom, C. Akujor","doi":"10.37121/jase.v4i1.140","DOIUrl":"https://doi.org/10.37121/jase.v4i1.140","url":null,"abstract":"The major cause of deterioration in lead-acid batteries is sulfation. There are patents on the use of high-frequency pulse desulfators to desulfate lead-acid batteries. Also, many products available in the market worldwide claim to use this technique to effectively desulfate lead-acid batteries that deteriorate due to sulfation. But there are little or no systematic studies to evaluate the performance of these products to know whether they do what their manufacturers claim. This research, therefore, aims at empirically evaluating one of such products. Four fully charged 100 Ampere-hour Valve Regulated Lead-Acid Gel batteries were discharged with an electronic-load battery discharger to ascertain their capacities. Thereafter, a high-frequency pulse desulfator was connected to desulfate the battery bank consisting of the four batteries. The battery bank was connected to be charged at the same time by a photovoltaic system. The desulfation experiment lasted for ten weeks but the batteries were tested to know their capacities after two, six, and ten weeks. The results show that the desulfation device works in desulfating lead-acid batteries as there are different degrees of improvement on the capacity of all the batteries. The percentage improvement in the capacity of the batteries is 89.5%, 75.9%, 1.6% and 1.4%, for batteries 1, 2, 3 and 4, respectively.","PeriodicalId":92218,"journal":{"name":"International journal of advances in science, engineering and technology","volume":"6 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-01-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87290010","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Akintunde Samson Alayande, I. Okakwu, O. Olabode, Okwuchukwu K. Nwankwoh
The occurrence of faults in any operational power system network is inevitable, and many of the causative factors such as lightning, thunderstorm among others is usually beyond human control. Consequently, there is the need to set up models capable of prompt identification and classification of these faults for immediate action. This paper, explored the use of artificial neural network (ANN) technique to identify and classify various faults on the 11 kV distribution network of University of Lagos. The ANN is applied because it offers high speed, higher efficiency and requires less human intervention. Datasets of the case study obtained were sectioned proportionately for training, testing, and validation. The mathematical formulations for the method are presented with python used as the programming tools for the analysis. The results obtained from this study, for both the voltage and current under different scenarios of faults, are displayed in graphical forms and discussed. The results showed the effectiveness of the ANN in fault identification and classification in a distribution network as the model yielded satisfactory results for the available limited datasets used. The information obtained from this study could be helpful to the system operators in faults identification and classification for making informed decisions regarding power system design and reliability.
{"title":"Analysis of unsymmetrical faults based on artificial neural network using 11 kV distribution network of University of Lagos as case study","authors":"Akintunde Samson Alayande, I. Okakwu, O. Olabode, Okwuchukwu K. Nwankwoh","doi":"10.37121/jase.v4i1.91","DOIUrl":"https://doi.org/10.37121/jase.v4i1.91","url":null,"abstract":"The occurrence of faults in any operational power system network is inevitable, and many of the causative factors such as lightning, thunderstorm among others is usually beyond human control. Consequently, there is the need to set up models capable of prompt identification and classification of these faults for immediate action. This paper, explored the use of artificial neural network (ANN) technique to identify and classify various faults on the 11 kV distribution network of University of Lagos. The ANN is applied because it offers high speed, higher efficiency and requires less human intervention. Datasets of the case study obtained were sectioned proportionately for training, testing, and validation. The mathematical formulations for the method are presented with python used as the programming tools for the analysis. The results obtained from this study, for both the voltage and current under different scenarios of faults, are displayed in graphical forms and discussed. The results showed the effectiveness of the ANN in fault identification and classification in a distribution network as the model yielded satisfactory results for the available limited datasets used. The information obtained from this study could be helpful to the system operators in faults identification and classification for making informed decisions regarding power system design and reliability.","PeriodicalId":92218,"journal":{"name":"International journal of advances in science, engineering and technology","volume":"42 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-01-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82724733","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The goal of this paper is the comparative analysis of three injection fluid options: Surfactant-enhanced-Water (SeW), Water Alternating Gas (WAG) and Surfactant-enhanced-WAG (SeWAG). The objectives are to identify the best option with the highest oil and gas displacement efficiency and the best development strategy for optimum recoveries in concurrent development of an oil rim reservoir. The Eclipse simulator was used because of its robust ability in simulating various injection options of an oil rim reservoir in a green field. Four scenarios (base case/no injection, SeW, WAG and SeWAG injections) were simulated under the same conditions to determine injection option with the best displacement efficiency and recoveries of oil and gas. Statistical analysis using Pareto chart was performed for proper identification of the option with the best recoveries. The result showed that SeWAG injection ratio 1:4:2 and injection cycles 56 gave the best recoveries for oil and gas with displacement efficiency of 0.08 and 0.332 respectively, followed by SeW injection with values of 0.073 and 0.331 respectively, while WAG has the least performance. On the Pareto chart, SeWAG simulation result has the highest percentage among the options with the best recoveries of 3.35 MMSTB oil and 16.05 BSCF gas, which is 12.53% and 16.12% of oil and gas in place after 9.6% of oil and 15.1% of gas have been recovered by natural depletion. Hence, this study has shown that two stages of development strategy (combination of natural depletion and SeWAG injection when the reservoir pressure is depleted) give cumulative effect for optimal recoveries in concurrent development of oil rim reservoir.
{"title":"Comparative studies of surfactant-enhanced-water, WAG and surfactant-enhanced-WAG injections in concurrent development of thin oil rim reservoir","authors":"S. O. Salufu, S. Isehunwa, R. Onolemhemhen","doi":"10.37121/jase.v3i2.105","DOIUrl":"https://doi.org/10.37121/jase.v3i2.105","url":null,"abstract":"The goal of this paper is the comparative analysis of three injection fluid options: Surfactant-enhanced-Water (SeW), Water Alternating Gas (WAG) and Surfactant-enhanced-WAG (SeWAG). The objectives are to identify the best option with the highest oil and gas displacement efficiency and the best development strategy for optimum recoveries in concurrent development of an oil rim reservoir. The Eclipse simulator was used because of its robust ability in simulating various injection options of an oil rim reservoir in a green field. Four scenarios (base case/no injection, SeW, WAG and SeWAG injections) were simulated under the same conditions to determine injection option with the best displacement efficiency and recoveries of oil and gas. Statistical analysis using Pareto chart was performed for proper identification of the option with the best recoveries. The result showed that SeWAG injection ratio 1:4:2 and injection cycles 56 gave the best recoveries for oil and gas with displacement efficiency of 0.08 and 0.332 respectively, followed by SeW injection with values of 0.073 and 0.331 respectively, while WAG has the least performance. On the Pareto chart, SeWAG simulation result has the highest percentage among the options with the best recoveries of 3.35 MMSTB oil and 16.05 BSCF gas, which is 12.53% and 16.12% of oil and gas in place after 9.6% of oil and 15.1% of gas have been recovered by natural depletion. Hence, this study has shown that two stages of development strategy (combination of natural depletion and SeWAG injection when the reservoir pressure is depleted) give cumulative effect for optimal recoveries in concurrent development of oil rim reservoir.","PeriodicalId":92218,"journal":{"name":"International journal of advances in science, engineering and technology","volume":"111 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-08-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88062333","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In this paper, surface data meteorological were used as input variables to create, train and validate the network in which global solar radiation serves as a target. These surface data were obtained from the archives of the European centre for Medium-Range weather forecast for a span of 36 years (1980-2015) over Nigeria. The research aims to evaluate the predictive ability of the nonlinear autoregressive neural network with exogenous input (NARX) model compared with the multivariate linear regression (MLR) model using the statistical metrics. Model selection analysis using the index of agreement (dr) metric showed that the MLR and NARX models have values of 0.710 and 0.853 in the Sahel, 0.748 and 0.849 in the Guinea Savannah, 0.664 and 0.791 in the Derived Savannah, 0.634 and 0.824 in the Coastal regions, and 0.771 and 0.806 in entire Nigeria respectively. Meanwhile, error analyses of the models using root mean square errors (RMSE) showed the values of 1.720 W/m2 and 1.417 in the Sahel region, 2.329 W/m2 and 1.985 W/m2 in the Guinea Savannah region, 2.459 W/m2 and 2.272 W/m2 in the Derived Savannah region, 2.397 W/m2 and 2.261 W/m2 in the Coastal region and 1.691 W/m2 and 1.600 W/m2 in entire Nigeria for MLR and NARX models respectively. These showed that the NARX model has higher dr values and lower RMSE values over all the climatic regions and entire Nigeria than the MLR model. Finally, it can be inferred from these metrics that the NARX model gives a better prediction of global solar radiation than the traditional common MLR models in all the zones in Nigeria.
本文以地面气象数据作为输入变量，建立、训练和验证以全球太阳辐射为目标的网络。这些地面数据来自欧洲中期天气预报中心(European centre for Medium-Range weather forecasting)对尼日利亚36年(1980-2015)的记录。本研究旨在利用统计指标比较外生输入非线性自回归神经网络(NARX)模型与多元线性回归(MLR)模型的预测能力。采用一致性指数(dr)指标进行模型选择分析表明，萨赫勒地区的MLR和NARX模型分别为0.710和0.853，几内亚大草原为0.748和0.849，衍生大草原为0.664和0.791，沿海地区为0.634和0.824，尼日利亚全境为0.771和0.806。同时，利用均方根误差(RMSE)对模型进行误差分析，结果表明，在萨赫勒地区，MLR和NARX模型的误差分别为1.720和1.417 W/m2，几内亚萨凡纳地区为2.329和1.985 W/m2, Derived萨凡纳地区为2.459和2.272 W/m2，沿海地区为2.397和2.261 W/m2，尼日利亚全国为1.691和1.600 W/m2。结果表明，与MLR模式相比，NARX模式在所有气候区和整个尼日利亚的dr值较高，RMSE值较低。最后，从这些指标可以推断出，在尼日利亚所有地区，NARX模式对全球太阳辐射的预测比传统的通用MLR模式更好。
{"title":"Application of nonlinear autoregressive neural network to estimation of global solar radiation over Nigeria","authors":"O. Ojo, B. Adeyemi","doi":"10.37121/jase.v3i2.98","DOIUrl":"https://doi.org/10.37121/jase.v3i2.98","url":null,"abstract":"In this paper, surface data meteorological were used as input variables to create, train and validate the network in which global solar radiation serves as a target. These surface data were obtained from the archives of the European centre for Medium-Range weather forecast for a span of 36 years (1980-2015) over Nigeria. The research aims to evaluate the predictive ability of the nonlinear autoregressive neural network with exogenous input (NARX) model compared with the multivariate linear regression (MLR) model using the statistical metrics. Model selection analysis using the index of agreement (dr) metric showed that the MLR and NARX models have values of 0.710 and 0.853 in the Sahel, 0.748 and 0.849 in the Guinea Savannah, 0.664 and 0.791 in the Derived Savannah, 0.634 and 0.824 in the Coastal regions, and 0.771 and 0.806 in entire Nigeria respectively. Meanwhile, error analyses of the models using root mean square errors (RMSE) showed the values of 1.720 W/m2 and 1.417 in the Sahel region, 2.329 W/m2 and 1.985 W/m2 in the Guinea Savannah region, 2.459 W/m2 and 2.272 W/m2 in the Derived Savannah region, 2.397 W/m2 and 2.261 W/m2 in the Coastal region and 1.691 W/m2 and 1.600 W/m2 in entire Nigeria for MLR and NARX models respectively. These showed that the NARX model has higher dr values and lower RMSE values over all the climatic regions and entire Nigeria than the MLR model. Finally, it can be inferred from these metrics that the NARX model gives a better prediction of global solar radiation than the traditional common MLR models in all the zones in Nigeria.","PeriodicalId":92218,"journal":{"name":"International journal of advances in science, engineering and technology","volume":"180 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-08-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76928187","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
C. Ocheri, Augustine D. Omah, C. N. Mbah, R. E. Njoku, N. A. Urama, C. W. Onyia, Sani M. Adam, J. Ezeanyanwu
Heavy metals pollution potential in National Iron Ore Mining Company, Itakpe was investigated. Two mining sites located at the east mining pits such as M3O, which is 370 m above sea level and M2O, which is 350 m above sea level were studied. Sequential extraction techniques was utilised to examine the distribution effect of the heavy metals pollution potential on the environment. Twelve representative (six-soil, two-sediment, two-plant and two-water) samples were collected, pre-treated and prepared for this study. The atomic absorption spectrometer was used to analyse the concentration of the metals after the sequential and single-stage extractions were determined. Results showed that Chromium, Arsenic, Cadmium and Copper are more bioavailable in the study area than Lead and Iron. This findings indicate that human, animals and plants are exposed to toxic elements (metals and metalloids).
{"title":"Heavy metals pollution potentials in the National Iron Ore Mining Company, Itakpe","authors":"C. Ocheri, Augustine D. Omah, C. N. Mbah, R. E. Njoku, N. A. Urama, C. W. Onyia, Sani M. Adam, J. Ezeanyanwu","doi":"10.37121/jase.v3i2.101","DOIUrl":"https://doi.org/10.37121/jase.v3i2.101","url":null,"abstract":"Heavy metals pollution potential in National Iron Ore Mining Company, Itakpe was investigated. Two mining sites located at the east mining pits such as M3O, which is 370 m above sea level and M2O, which is 350 m above sea level were studied. Sequential extraction techniques was utilised to examine the distribution effect of the heavy metals pollution potential on the environment. Twelve representative (six-soil, two-sediment, two-plant and two-water) samples were collected, pre-treated and prepared for this study. The atomic absorption spectrometer was used to analyse the concentration of the metals after the sequential and single-stage extractions were determined. Results showed that Chromium, Arsenic, Cadmium and Copper are more bioavailable in the study area than Lead and Iron. This findings indicate that human, animals and plants are exposed to toxic elements (metals and metalloids).","PeriodicalId":92218,"journal":{"name":"International journal of advances in science, engineering and technology","volume":"139 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-08-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73771016","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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