Kehinde Oladoke Olatunji, O. Ogunkunle, Oladunni Adeleke Adisa, Adewumi Taiwo
Agricultural mechanization is an essential factor influencing agricultural output and the profitability of farming activities. The influence of agricultural mechanization on agricultural production in Lagos State, where the majority of the farmers use modern technologies for their farming operations, was investigated. The investigative research approach method was employed to retrieve information from farmers through a structured questionnaire. A five rating scale questionnaire was utilized for the respondents to show their level of agreement or disagreement. The percentage was used to analyze the respondents' bio-data. At the same time, the mean was employed to answer the research questions. The null hypotheses were tested using Chi-square statistics at 0.05 significant levels. The results revealed that agricultural mechanization increased the cultivated land, crop yields, and farmers’ income with cumulative means of 2.34, 1.07, and 1.44, respectively. Socioeconomic characteristics, available technology, and government policies influenced agricultural mechanization with cumulative means of 1.93, 1.24, and 1.79, respectively. The entire six hypotheses were rejected based on the results of the Chi-square statistics with the calculated X2 values of 8,989.09, 473.59, 3,977.42, 2,192.63, 226.07 and, 1,878.05; and critical X2 values of 46.19, 46.19, 36.42, 31.41, 21.03, and 31.41, for the significant effect on the size of land cultivated, crop yield, farmer’s income, socioeconomic characteristics, available technology, and government policies respectively. The study showed that agricultural mechanization had a significant influence on crop production and farmers’ income. Therefore, there is a need to improve the available technologies and formulate and implement policies to make agricultural mechanization accessible and sustainable.
{"title":"Effect of Agricultural Mechanization on Production and Farmers Economy in Nigeria: A Case Study of Lagos State","authors":"Kehinde Oladoke Olatunji, O. Ogunkunle, Oladunni Adeleke Adisa, Adewumi Taiwo","doi":"10.4028/p-414rk3","DOIUrl":"https://doi.org/10.4028/p-414rk3","url":null,"abstract":"Agricultural mechanization is an essential factor influencing agricultural output and the profitability of farming activities. The influence of agricultural mechanization on agricultural production in Lagos State, where the majority of the farmers use modern technologies for their farming operations, was investigated. The investigative research approach method was employed to retrieve information from farmers through a structured questionnaire. A five rating scale questionnaire was utilized for the respondents to show their level of agreement or disagreement. The percentage was used to analyze the respondents' bio-data. At the same time, the mean was employed to answer the research questions. The null hypotheses were tested using Chi-square statistics at 0.05 significant levels. The results revealed that agricultural mechanization increased the cultivated land, crop yields, and farmers’ income with cumulative means of 2.34, 1.07, and 1.44, respectively. Socioeconomic characteristics, available technology, and government policies influenced agricultural mechanization with cumulative means of 1.93, 1.24, and 1.79, respectively. The entire six hypotheses were rejected based on the results of the Chi-square statistics with the calculated X2 values of 8,989.09, 473.59, 3,977.42, 2,192.63, 226.07 and, 1,878.05; and critical X2 values of 46.19, 46.19, 36.42, 31.41, 21.03, and 31.41, for the significant effect on the size of land cultivated, crop yield, farmer’s income, socioeconomic characteristics, available technology, and government policies respectively. The study showed that agricultural mechanization had a significant influence on crop production and farmers’ income. Therefore, there is a need to improve the available technologies and formulate and implement policies to make agricultural mechanization accessible and sustainable.","PeriodicalId":45925,"journal":{"name":"International Journal of Engineering Research in Africa","volume":"60 1","pages":"211 - 231"},"PeriodicalIF":0.7,"publicationDate":"2022-05-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45564016","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}
I. E. Kalu, Ericmoore Jossou, E. K. Arthur, S. Ja'afaru, E. Ishidi
Oil shales have unstable mechanical and chemical properties, which makes their extraction for characterization and conventional mechanical testing uneasy and complex. Most often, mechanical property measurements are usually taken from core samples that are costly to extract and test using conventional testing methods. This paper presents a focused study carried out on oil shale cuttings obtained from the sidewalls of two different wellbore depths in the Niger Delta area of Nigeria. Using the X-ray Diffraction (XRD) and Scanning Electron Microscope (SEM) characterization techniques, the morphology of these shales was studied. The results obtained clearly showed the composition, bonding and variations in the morphology of the studied shale samples. Furthermore, the heterogeneity associated with these shales across varied depths were revealed. An efficient and less expensive technique compared to conventional testing methods, instrumented indentation testing (IIT) was carried out to obtain essential mechanical parameters of the shale specimen. These properties are important parameters in determining the hydrocarbon storage space of shale formations, wellbore stability, and optimization of hydraulic fracturing which is necessary for efficient drilling operations.
{"title":"Characterization and Mechanical Property Measurements by Instrumented Indentation Testing of Niger Delta Oil Shale Cuttings","authors":"I. E. Kalu, Ericmoore Jossou, E. K. Arthur, S. Ja'afaru, E. Ishidi","doi":"10.4028/p-2m9z7g","DOIUrl":"https://doi.org/10.4028/p-2m9z7g","url":null,"abstract":"Oil shales have unstable mechanical and chemical properties, which makes their extraction for characterization and conventional mechanical testing uneasy and complex. Most often, mechanical property measurements are usually taken from core samples that are costly to extract and test using conventional testing methods. This paper presents a focused study carried out on oil shale cuttings obtained from the sidewalls of two different wellbore depths in the Niger Delta area of Nigeria. Using the X-ray Diffraction (XRD) and Scanning Electron Microscope (SEM) characterization techniques, the morphology of these shales was studied. The results obtained clearly showed the composition, bonding and variations in the morphology of the studied shale samples. Furthermore, the heterogeneity associated with these shales across varied depths were revealed. An efficient and less expensive technique compared to conventional testing methods, instrumented indentation testing (IIT) was carried out to obtain essential mechanical parameters of the shale specimen. These properties are important parameters in determining the hydrocarbon storage space of shale formations, wellbore stability, and optimization of hydraulic fracturing which is necessary for efficient drilling operations.","PeriodicalId":45925,"journal":{"name":"International Journal of Engineering Research in Africa","volume":"59 1","pages":"89 - 100"},"PeriodicalIF":0.7,"publicationDate":"2022-03-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45997146","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}
Djamel Edinne Gaagaia, Mustapha Bouakba, M. M. Barbero-Barrera, Layachi Abdelheq, N. Boutasseta
In this paper, morphological, physico-chemical and thermal properties investigations are carried out for a novel composite material reinforced by Washingtonia Filifera (WF) palm fibers using a 20 weight (wt) % loading rate. The experimental analysis by Scanning Electron Microscopy (SEM) shows the longitudinal roughness of the surface, which plays a very important role in the adhesion between the WF fibers and the High Density PolyethylenE (HDPE) resin. FTIR tests of the composite (WF 20%/ HDPE) represent out of plane vibrations involving ring and CH2 symmetric bending in cellulose chain. Thermogravimetric analysis (TGA) and Derivative thermogravimetric (DTG) thermal analysis show a thermal stability at 210°C, 2.5% residual mass and 745 °C maximum temperature. X-Ray Diffraction (XRD) analysis shows that the crystallinity index is 59.2%, with a size of 23 nm. Using tensile tests, a Young modulus of 858.6 MPa, 17% elongation and a maximum stress of 15 MPa are found. The obtained characteristics of WF reinforced composite are better than those of Bamboo reinforced composites which has been proven to have characteristics superior to those of standard particleboard and medium density fiberboard used mainly in the construction industry.
{"title":"Physico-Chemical and Thermomechanical Analysis and Characterization of a Thermoplastic Composite Material Reinforced by Washingtonia Filifera Novel Vegetable Fibers","authors":"Djamel Edinne Gaagaia, Mustapha Bouakba, M. M. Barbero-Barrera, Layachi Abdelheq, N. Boutasseta","doi":"10.4028/p-8ew64s","DOIUrl":"https://doi.org/10.4028/p-8ew64s","url":null,"abstract":"In this paper, morphological, physico-chemical and thermal properties investigations are carried out for a novel composite material reinforced by Washingtonia Filifera (WF) palm fibers using a 20 weight (wt) % loading rate. The experimental analysis by Scanning Electron Microscopy (SEM) shows the longitudinal roughness of the surface, which plays a very important role in the adhesion between the WF fibers and the High Density PolyethylenE (HDPE) resin. FTIR tests of the composite (WF 20%/ HDPE) represent out of plane vibrations involving ring and CH2 symmetric bending in cellulose chain. Thermogravimetric analysis (TGA) and Derivative thermogravimetric (DTG) thermal analysis show a thermal stability at 210°C, 2.5% residual mass and 745 °C maximum temperature. X-Ray Diffraction (XRD) analysis shows that the crystallinity index is 59.2%, with a size of 23 nm. Using tensile tests, a Young modulus of 858.6 MPa, 17% elongation and a maximum stress of 15 MPa are found. The obtained characteristics of WF reinforced composite are better than those of Bamboo reinforced composites which has been proven to have characteristics superior to those of standard particleboard and medium density fiberboard used mainly in the construction industry.","PeriodicalId":45925,"journal":{"name":"International Journal of Engineering Research in Africa","volume":"59 1","pages":"43 - 55"},"PeriodicalIF":0.7,"publicationDate":"2022-03-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42387453","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}
Generally, expansive soils undergoes significant volumetric deformation, which causes structural damages to existing infrastructures. Damages due to expansive activities are noticeable in pavements, buildings, earth dams, retaining walls etc. To estimate swelling stress, accurate assessment of soil absorption of water over time, with respect to soil volumetric change is required. However, the time frame requires for completion of swelling cycle is relatively long. With this in view, several attempts with great success have been made by researchers to predict swelling pressure of expansive soils using soil mechanics index properties. In this study, the interrelation between unsaturated soil mechanics property i.e. Matric suction () and geotechnical soil indexes were utilized to develop three predictive multi-regression equation for swelling stress. Series of Atterberg limit tests, matric suction tests, free swell index (FSI) tests and zero swelling tests (ZST) were performed to obtain the dependent and independent variables for the multi-regression analysis. Based on the experimental results, empirical relationships were developed to determine swelling stress as a function of matric suction, gravimetric moisture content (GMC), FSI, dry density and plasticity index using mathematical software package (NCSS11). The developed predictive multi-regression models were used to estimate the experimental swelling stress (. The scattered plot showed good agreement between the measured and predicted data, with coefficient of determination (R2) and mean square error (MSE) of 0.9443, 0.9793, 0.9310 and 0.0051%, 0.0021% and 0.0067% for models 1, 2 and 3 respectively.
{"title":"Swelling Pressure Prediction of Compacted Unsaturated Expansive Soils","authors":"Aneke Frank Ikechukwu, M. Mostafa","doi":"10.4028/p-eq1419","DOIUrl":"https://doi.org/10.4028/p-eq1419","url":null,"abstract":"Generally, expansive soils undergoes significant volumetric deformation, which causes structural damages to existing infrastructures. Damages due to expansive activities are noticeable in pavements, buildings, earth dams, retaining walls etc. To estimate swelling stress, accurate assessment of soil absorption of water over time, with respect to soil volumetric change is required. However, the time frame requires for completion of swelling cycle is relatively long. With this in view, several attempts with great success have been made by researchers to predict swelling pressure of expansive soils using soil mechanics index properties. In this study, the interrelation between unsaturated soil mechanics property i.e. Matric suction () and geotechnical soil indexes were utilized to develop three predictive multi-regression equation for swelling stress. Series of Atterberg limit tests, matric suction tests, free swell index (FSI) tests and zero swelling tests (ZST) were performed to obtain the dependent and independent variables for the multi-regression analysis. Based on the experimental results, empirical relationships were developed to determine swelling stress as a function of matric suction, gravimetric moisture content (GMC), FSI, dry density and plasticity index using mathematical software package (NCSS11). The developed predictive multi-regression models were used to estimate the experimental swelling stress (. The scattered plot showed good agreement between the measured and predicted data, with coefficient of determination (R2) and mean square error (MSE) of 0.9443, 0.9793, 0.9310 and 0.0051%, 0.0021% and 0.0067% for models 1, 2 and 3 respectively.","PeriodicalId":45925,"journal":{"name":"International Journal of Engineering Research in Africa","volume":"59 1","pages":"119 - 134"},"PeriodicalIF":0.7,"publicationDate":"2022-03-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48780587","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 paper addresses the problems of control and energy management in micro-grid with the incorporation of renewable energy generation, hybrid storage technologies, and the integration of the electric vehicles (EVs) with vehicle to grid (V2G) technology. The adaptive model predictive control (AMPC) technique is used to optimize the charge/discharge of the EVs in a receding horizon manner in order to reduce operational cost in a renewable energy-based micro-grid. V2G systems integration can be a crucial element in the assurance of network reliability against variability in loads. In this context, the paper presents an AMPC algorithm for the optimization of a micro-grid coupled with a V2G system consisting of six electric vehicle charging stations. The proposed algorithm effectively manages the use of renewable energy sources, vehicles charge, energy storage units, and the purchase and sale of electric power to the external network. Two scenarios are investigated in this paper to examine the performance of the proposed controller to manage the renewable energy sources in the micro-grid system. The first case uses a load shifting mechanism to solve the charge management problem during a known interval of parking time. The second case introduces the EVs with V2G capabilities when connected with the micro-grid. In this case, the vehicle battery collaborates with the ESS of the micro-grid to maximize costs benefits and mitigate the intermittency of renewable generation. Furthermore, other benefits of V2G concepts, such as voltage and frequency control for the micro-grid stability, are investigated. Therefore, it is evident from the obtained results that the proposed control algorithm was able to effectively manage the renewable energy sources, energy storage units, vehicles charge, and the purchase and sale of electric power with the grid. Keywords: Adaptive model predictive control, Energy management system, Electric vehicles, Vehicle to grid technology, Grid reliability, Load shifting, Optimization problem and MATLAB/Simulink.
{"title":"Predictive Control of Adaptive Micro-Grid Energy Management System Considering Electric Vehicles Integration","authors":"P. Gbadega, A. Saha","doi":"10.4028/p-42m5ip","DOIUrl":"https://doi.org/10.4028/p-42m5ip","url":null,"abstract":"This paper addresses the problems of control and energy management in micro-grid with the incorporation of renewable energy generation, hybrid storage technologies, and the integration of the electric vehicles (EVs) with vehicle to grid (V2G) technology. The adaptive model predictive control (AMPC) technique is used to optimize the charge/discharge of the EVs in a receding horizon manner in order to reduce operational cost in a renewable energy-based micro-grid. V2G systems integration can be a crucial element in the assurance of network reliability against variability in loads. In this context, the paper presents an AMPC algorithm for the optimization of a micro-grid coupled with a V2G system consisting of six electric vehicle charging stations. The proposed algorithm effectively manages the use of renewable energy sources, vehicles charge, energy storage units, and the purchase and sale of electric power to the external network. Two scenarios are investigated in this paper to examine the performance of the proposed controller to manage the renewable energy sources in the micro-grid system. The first case uses a load shifting mechanism to solve the charge management problem during a known interval of parking time. The second case introduces the EVs with V2G capabilities when connected with the micro-grid. In this case, the vehicle battery collaborates with the ESS of the micro-grid to maximize costs benefits and mitigate the intermittency of renewable generation. Furthermore, other benefits of V2G concepts, such as voltage and frequency control for the micro-grid stability, are investigated. Therefore, it is evident from the obtained results that the proposed control algorithm was able to effectively manage the renewable energy sources, energy storage units, vehicles charge, and the purchase and sale of electric power with the grid. Keywords: Adaptive model predictive control, Energy management system, Electric vehicles, Vehicle to grid technology, Grid reliability, Load shifting, Optimization problem and MATLAB/Simulink.","PeriodicalId":45925,"journal":{"name":"International Journal of Engineering Research in Africa","volume":"59 1","pages":"175 - 204"},"PeriodicalIF":0.7,"publicationDate":"2022-03-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47700601","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}
Abstract. Fluid flows through curved pipes are frequently encountered in various industrial or biomedical applications. These flows, under the effect of the centrifugal force resulting from the curvature of the pipe, causes an instability phenomenon known as Dean instability, which results in the appearance of two or more counter-rotating vortex cells. The objective of this work is to determine numerically the effect of geometric parameters and rheological behavior of the fluid, including the index of behavior on the occurrence and development of the instability of Dean in a 180° curved duct. The governing equations including the full Navier-Stokes, the continuity and the Momentum are solved in three dimensions using the commercial code ANSYS-CFX, under the conditions of laminar, stationary and incompressible flow. In the first part, the results of the flow of a shear thinning fluid and a shear thickening fluid for a Dean number Dn = 125 and a radius of curvature Rc = 15.1 are presented. These calculation results gave a good agreement with the measured values extracted from the literature. The second part concerns the influence of the curvature ratio and the rheological behaviour of the fluid, the presence of two stationary secondary recirculations, as well as the appearance and the development of two additional vortices are highlighted. The main point observed is that the decrease in the curvature radius increases the instability of the flow through the pipe and this increases the number of vortex cells (Dean vortex). The velocity of the flow and its rheological nature are essential parameters for the reduction of instability in the canal.
{"title":"Study of the Rheological Behaviour and the Curvature Radius Effects on a Non Newtonian Fluid Flow in a Curved Square Duct","authors":"Fayçal Bouzit, M. Bouzit, Mourad Mokeddem","doi":"10.4028/p-ll8x57","DOIUrl":"https://doi.org/10.4028/p-ll8x57","url":null,"abstract":"Abstract. Fluid flows through curved pipes are frequently encountered in various industrial or biomedical applications. These flows, under the effect of the centrifugal force resulting from the curvature of the pipe, causes an instability phenomenon known as Dean instability, which results in the appearance of two or more counter-rotating vortex cells. The objective of this work is to determine numerically the effect of geometric parameters and rheological behavior of the fluid, including the index of behavior on the occurrence and development of the instability of Dean in a 180° curved duct. The governing equations including the full Navier-Stokes, the continuity and the Momentum are solved in three dimensions using the commercial code ANSYS-CFX, under the conditions of laminar, stationary and incompressible flow. In the first part, the results of the flow of a shear thinning fluid and a shear thickening fluid for a Dean number Dn = 125 and a radius of curvature Rc = 15.1 are presented. These calculation results gave a good agreement with the measured values extracted from the literature. The second part concerns the influence of the curvature ratio and the rheological behaviour of the fluid, the presence of two stationary secondary recirculations, as well as the appearance and the development of two additional vortices are highlighted. The main point observed is that the decrease in the curvature radius increases the instability of the flow through the pipe and this increases the number of vortex cells (Dean vortex). The velocity of the flow and its rheological nature are essential parameters for the reduction of instability in the canal.","PeriodicalId":45925,"journal":{"name":"International Journal of Engineering Research in Africa","volume":"59 1","pages":"225 - 238"},"PeriodicalIF":0.7,"publicationDate":"2022-03-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49339194","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}
Electricity supply in Oman is very stable, however, power generation from gas turbines and fossil fuels, which are not environmentally friendly, contribute over ninety percent to the present power grid. Due to rapid development, the current power state of Oman is been over stretched. This is as a result of increased power demand, considering the size of the electricity network and the control strategies employed at different levels of the power system. Therefore, in order to keep pace with the recent development, it is paramount to integrate the current power grid of the country with smart grid technologies. Some of the benefits of employing smart grid technologies are; providing more reliable power, utilizing more efficient renewable power, employing a mix of energy sources, use of smart devices, mitigating carbon footprint, enabling the roadmap for electric vehicles, availing smart job opportunities, saving of energy via reduced consumption programs, improved customer services, accurate billings, detection of frauds and technical losses, increased competition, and levelling of the demand curve or peak reduction. This paper presents the dynamics of making the power grid of Oman smarter, based on the current power situation in the country. The paper addresses the penetration of smart grid technologies with the national power grid and also present an extensive review of power situation of Oman power system. Efforts were made to discuss the possible locations of wind and solar energy potentials, in the country, since they are the two commonly used and readily available renewable energy sources. There is no doubt that smart grid technologies like information and communication technology, data management, energy sales and smart metering strategies, would play a huge role in making the power grid smarter. In addition, some dynamic behavior of the power grid was analyzed considering the penetration of solar and wind energy, in the current power grid of Oman.
{"title":"Dynamics of a Smarter Grid Operation in the Current Power Situation of Oman","authors":"Saif Al Omairi, K. Okedu, Maryam Hasan Al Balushi","doi":"10.4028/p-fnxrm9","DOIUrl":"https://doi.org/10.4028/p-fnxrm9","url":null,"abstract":"Electricity supply in Oman is very stable, however, power generation from gas turbines and fossil fuels, which are not environmentally friendly, contribute over ninety percent to the present power grid. Due to rapid development, the current power state of Oman is been over stretched. This is as a result of increased power demand, considering the size of the electricity network and the control strategies employed at different levels of the power system. Therefore, in order to keep pace with the recent development, it is paramount to integrate the current power grid of the country with smart grid technologies. Some of the benefits of employing smart grid technologies are; providing more reliable power, utilizing more efficient renewable power, employing a mix of energy sources, use of smart devices, mitigating carbon footprint, enabling the roadmap for electric vehicles, availing smart job opportunities, saving of energy via reduced consumption programs, improved customer services, accurate billings, detection of frauds and technical losses, increased competition, and levelling of the demand curve or peak reduction. This paper presents the dynamics of making the power grid of Oman smarter, based on the current power situation in the country. The paper addresses the penetration of smart grid technologies with the national power grid and also present an extensive review of power situation of Oman power system. Efforts were made to discuss the possible locations of wind and solar energy potentials, in the country, since they are the two commonly used and readily available renewable energy sources. There is no doubt that smart grid technologies like information and communication technology, data management, energy sales and smart metering strategies, would play a huge role in making the power grid smarter. In addition, some dynamic behavior of the power grid was analyzed considering the penetration of solar and wind energy, in the current power grid of Oman.","PeriodicalId":45925,"journal":{"name":"International Journal of Engineering Research in Africa","volume":"59 1","pages":"151 - 173"},"PeriodicalIF":0.7,"publicationDate":"2022-03-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48552027","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 study investigated the optimization of process parameters for adsorption of hexavalent chromium with activated carbons extracted from palm tree leaves of Nigerian origin. The effect of process parameters such as adsorbent dosage, initial chromium concentration, temperature, contact time, and adsorbent particle size was studied with the aid of Central Composite Design. The result showed that for the adsorbent dosage, initial concentration, temperature, contact time, and particle size, the optimum conditions were found to be 20 mg, 80 mg/l, 40° C, 40 minutes, and 1400µm, respectively. The actual and predicted values obtained were 72.96 % as well as 70.33 %, respectively, indicating a good correlation with a comparatively small variance of 2.66 %. The Langmuir isotherm showed an R2 of 0.981 and thereby showing better linearity when compared with the Freundlich isotherm. The result of the adsorption kinetics indicated that it was better described by the Pseudo-second order model. The overall adsorption process on the other hand showed an exothermic reaction with an enthalpy value of -18.707. The values of Gibbs free energy (∆G) at various temperatures also revealed a spontaneous reaction and a positive value of entropy. The results obtained showed that the adsorbent was effective in the adsorption of hexavalent chromium.
{"title":"Optimization of Process Parameters for Adsorption of Hexavalent Chromium from Wastewater Using Response Surface Methodology","authors":"E. Ugwu, J. Agunwamba","doi":"10.4028/p-thc651","DOIUrl":"https://doi.org/10.4028/p-thc651","url":null,"abstract":"This study investigated the optimization of process parameters for adsorption of hexavalent chromium with activated carbons extracted from palm tree leaves of Nigerian origin. The effect of process parameters such as adsorbent dosage, initial chromium concentration, temperature, contact time, and adsorbent particle size was studied with the aid of Central Composite Design. The result showed that for the adsorbent dosage, initial concentration, temperature, contact time, and particle size, the optimum conditions were found to be 20 mg, 80 mg/l, 40° C, 40 minutes, and 1400µm, respectively. The actual and predicted values obtained were 72.96 % as well as 70.33 %, respectively, indicating a good correlation with a comparatively small variance of 2.66 %. The Langmuir isotherm showed an R2 of 0.981 and thereby showing better linearity when compared with the Freundlich isotherm. The result of the adsorption kinetics indicated that it was better described by the Pseudo-second order model. The overall adsorption process on the other hand showed an exothermic reaction with an enthalpy value of -18.707. The values of Gibbs free energy (∆G) at various temperatures also revealed a spontaneous reaction and a positive value of entropy. The results obtained showed that the adsorbent was effective in the adsorption of hexavalent chromium.","PeriodicalId":45925,"journal":{"name":"International Journal of Engineering Research in Africa","volume":"59 1","pages":"239 - 262"},"PeriodicalIF":0.7,"publicationDate":"2022-03-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43332097","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}
B. Bakri, Hani Benguesmia, A. Ketata, Slah Diriss, Z. Driss
This paper is intended to check the thermal convection flow during a new solar air heater (SAH) test bench, which is conducted in the LASEM laboratory. In fact, the applied system includes two-passage heater solar air separated by an absorber. On the other hand, a glass piece is connected to the box prototype via a pipe. Then, the piece of the glass is attached to the front side of this device in which an absorber is inserted. Moreover, two circular holes are made on the same face of the box prototype. The first is an entry hole through which hot air goes inside, and an exit hole through which air is released into the surrounding area. The study was conducted using the Navier-Stokes equations associated with the k–ω turbulence model through the use of the newly released Ansys 17.0 software to characterize the aero-thermal structure of our new system operating in natural convection. In these conditions, it has been observed that the hot zone created on the mirror side receiving the solar radiation generates an ascendant movement. It goes from the bottom to the top and enters the box prototype. The same phenomenon is also created in the box where the airflow coming from the solar heat escapes into the environment. This movement created between the hot zone of the solar heat and the box prototype is also imposed in the cold zone of the solar heat on the heat-insulating side. In these conditions, the air movement is however from the top to the bottom. Indeed, the acceleration of the air velocity at the inlet of the solar heat is due to the change of the section which is more reduced by comparison to the rest of the air circulation duct. Based on our experimental results generated in a two-passage solar air heater connected to the box prototype, the computational approach and the simulation results were validated. By referring to the classic solar air heater with one passage, the energy efficiency measured in the same conditions was enhanced and presented the efficient one with an improvement of about 27%. Finally, the numerical results are compared to our experimental results and those obtained by the authors. The comparison proved a good agreement.
{"title":"Numerical Simulation and Experimental Study of Natural Convection Flow in a Test Bench for Solar Air Heaters","authors":"B. Bakri, Hani Benguesmia, A. Ketata, Slah Diriss, Z. Driss","doi":"10.4028/p-muwal6","DOIUrl":"https://doi.org/10.4028/p-muwal6","url":null,"abstract":"This paper is intended to check the thermal convection flow during a new solar air heater (SAH) test bench, which is conducted in the LASEM laboratory. In fact, the applied system includes two-passage heater solar air separated by an absorber. On the other hand, a glass piece is connected to the box prototype via a pipe. Then, the piece of the glass is attached to the front side of this device in which an absorber is inserted. Moreover, two circular holes are made on the same face of the box prototype. The first is an entry hole through which hot air goes inside, and an exit hole through which air is released into the surrounding area. The study was conducted using the Navier-Stokes equations associated with the k–ω turbulence model through the use of the newly released Ansys 17.0 software to characterize the aero-thermal structure of our new system operating in natural convection. In these conditions, it has been observed that the hot zone created on the mirror side receiving the solar radiation generates an ascendant movement. It goes from the bottom to the top and enters the box prototype. The same phenomenon is also created in the box where the airflow coming from the solar heat escapes into the environment. This movement created between the hot zone of the solar heat and the box prototype is also imposed in the cold zone of the solar heat on the heat-insulating side. In these conditions, the air movement is however from the top to the bottom. Indeed, the acceleration of the air velocity at the inlet of the solar heat is due to the change of the section which is more reduced by comparison to the rest of the air circulation duct. Based on our experimental results generated in a two-passage solar air heater connected to the box prototype, the computational approach and the simulation results were validated. By referring to the classic solar air heater with one passage, the energy efficiency measured in the same conditions was enhanced and presented the efficient one with an improvement of about 27%. Finally, the numerical results are compared to our experimental results and those obtained by the authors. The comparison proved a good agreement.","PeriodicalId":45925,"journal":{"name":"International Journal of Engineering Research in Africa","volume":"59 1","pages":"205 - 223"},"PeriodicalIF":0.7,"publicationDate":"2022-03-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47484785","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}
Dieudonné Abessolo, A. Biwolé, D. Fokwa, B. M. Ganou Koungang, Yembe Benjamin Baah
This paper describes the physical, mechanical, and hygroscopic behaviour of compressed earth bricks (CEB) reinforced with fibres of Bambusa vulgaris. Three fibre contents (0.5, 0.75, and 1.0 wt.%) and lengths of fibre (4, 5 and 6 cm) were considered as reinforcement for the compressed earth blocks based on cement stabilisation with 8.0% of the weight of the mixture. CEB composites were compacted with a static loading by applying a compacting stress of 15 MPa. Results show that the appropriate addition of Bamboo fibres can improve mechanical properties of CEBs. In particular, the compressive strength increases by 43.6%, at an optimum fibre content of 0.5 wt.% and at a length of 4 cm. The compressive strength also increases of 24.6% and 25.6% for a fibre content of 0.75 wt.% at 4 cm long and for 0.5 wt.% at 5 cm long respectively. The flexural strength also increases with increase in fibre content and length of fibre. The highest value of flexural strength is obtained with CEB containing 1.0 wt.% of fibre content while the lowest value is obtained with blocks without reinforcement. For the water absorption, there is an increase by 18.4, 25.1 and 27.6% when the fibre content increases by 0 to 1.0 wt.% for fibres length of 4, 5 and 6 cm long, respectively. However, as the fibre content and length increase, the density decreases, and the porosity and water absorption increase due to their porous character and hydrophilic.
{"title":"Physical, Mechanical and Hygroscopic Behaviour of Compressed Earth Blocks Stabilized with Cement and Reinforced with Bamboo Fibres","authors":"Dieudonné Abessolo, A. Biwolé, D. Fokwa, B. M. Ganou Koungang, Yembe Benjamin Baah","doi":"10.4028/p-spbskv","DOIUrl":"https://doi.org/10.4028/p-spbskv","url":null,"abstract":"This paper describes the physical, mechanical, and hygroscopic behaviour of compressed earth bricks (CEB) reinforced with fibres of Bambusa vulgaris. Three fibre contents (0.5, 0.75, and 1.0 wt.%) and lengths of fibre (4, 5 and 6 cm) were considered as reinforcement for the compressed earth blocks based on cement stabilisation with 8.0% of the weight of the mixture. CEB composites were compacted with a static loading by applying a compacting stress of 15 MPa. Results show that the appropriate addition of Bamboo fibres can improve mechanical properties of CEBs. In particular, the compressive strength increases by 43.6%, at an optimum fibre content of 0.5 wt.% and at a length of 4 cm. The compressive strength also increases of 24.6% and 25.6% for a fibre content of 0.75 wt.% at 4 cm long and for 0.5 wt.% at 5 cm long respectively. The flexural strength also increases with increase in fibre content and length of fibre. The highest value of flexural strength is obtained with CEB containing 1.0 wt.% of fibre content while the lowest value is obtained with blocks without reinforcement. For the water absorption, there is an increase by 18.4, 25.1 and 27.6% when the fibre content increases by 0 to 1.0 wt.% for fibres length of 4, 5 and 6 cm long, respectively. However, as the fibre content and length increase, the density decreases, and the porosity and water absorption increase due to their porous character and hydrophilic.","PeriodicalId":45925,"journal":{"name":"International Journal of Engineering Research in Africa","volume":"59 1","pages":"29 - 41"},"PeriodicalIF":0.7,"publicationDate":"2022-03-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42956728","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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