This study explored coconut shells in developing Al-Cu-Mg based nanocomposites for fabricating mould parts. The aim is to engineer alternate way through which income can be generated from agricultural wastes and recycling of industrial waste like aluminium cans. Al-Cu-Mg based nanocomposites were produced and characterised. Effects of carbonised and uncarbonised coconut shell nanoparticle (UCSNP) additions on properties of Al-Cu-Mg nanocomposites were compared. Maximum tensile strength was obtained at 10%vol uncarbonised coconut shell nanoparticle additions to Al-Cu-Mg. Increase in tensile strength and elastic modulus were noted with carbonised coconut shell reinforced Al-Cu-Mg nanocomposites against the decrease in the elastic (Young’s) modulus of the UCSNP/Al-Cu-Mg nanocomposites. Despite highest tensile strength of 10%volUCSNP/Al-Cu-Mg, 10%volCCSNP/Al-Cu-Mg nanocomposite is ranked as the best material in this study due to its optimum combination of properties including tensile strength, elastic modulus, tensile strain, impact energy and hardness values. Hence, it has been selected for fabricating open die mould parts to be used in compression sheet forming process for fabricating polymeric standard samples for tensile flexural analyses. Keywords: Al-Cu-Mg, Coconut, Shell, Nanoparticles, Mould fabrication
{"title":"Coconut Shell Particle Reinforced Al-Cu-Mg Nanocomposites for Cavity Die Mould Parts Applications","authors":"S. Bello","doi":"10.4028/p-29l8h7","DOIUrl":"https://doi.org/10.4028/p-29l8h7","url":null,"abstract":"This study explored coconut shells in developing Al-Cu-Mg based nanocomposites for fabricating mould parts. The aim is to engineer alternate way through which income can be generated from agricultural wastes and recycling of industrial waste like aluminium cans. Al-Cu-Mg based nanocomposites were produced and characterised. Effects of carbonised and uncarbonised coconut shell nanoparticle (UCSNP) additions on properties of Al-Cu-Mg nanocomposites were compared. Maximum tensile strength was obtained at 10%vol uncarbonised coconut shell nanoparticle additions to Al-Cu-Mg. Increase in tensile strength and elastic modulus were noted with carbonised coconut shell reinforced Al-Cu-Mg nanocomposites against the decrease in the elastic (Young’s) modulus of the UCSNP/Al-Cu-Mg nanocomposites. Despite highest tensile strength of 10%volUCSNP/Al-Cu-Mg, 10%volCCSNP/Al-Cu-Mg nanocomposite is ranked as the best material in this study due to its optimum combination of properties including tensile strength, elastic modulus, tensile strain, impact energy and hardness values. Hence, it has been selected for fabricating open die mould parts to be used in compression sheet forming process for fabricating polymeric standard samples for tensile flexural analyses. Keywords: Al-Cu-Mg, Coconut, Shell, Nanoparticles, Mould fabrication","PeriodicalId":45925,"journal":{"name":"International Journal of Engineering Research in Africa","volume":"61 1","pages":"79 - 94"},"PeriodicalIF":0.7,"publicationDate":"2022-07-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48618679","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}
Omokafe Michael, Olatunde Borode, Oyelola Oladunni Alabi, K. Alaneme, A. Adesoji
Illegal disposal and recirculation of expired drugs is a global menace which can be solved by their re-utilization as corrosion inhibitors. Thus, helping to combat the current widespread corrosion-induced wastage of expensive mild steel infrastructure. The experimental investigation evaluated the capability and effectiveness of an expired drug (piroxicam) for inhibiting mild steel corrosion in blank 0.5M HCl and acidic environments containing 2 to 8 g/L of the expired drug. Spectrometry, weight loss analysis, atomic absorption spectroscopy, microscopy, polarisation and electrochemical impedance study (EIS) were employed. Analyses revealed drastic inhibition of corrosion in mild steel by expired piroxicam drug in the acid. Corrosion currents ( ) obtained at all concentrations of the expired drug were reduced in comparison to that of the uninhibited environment. The solution resistance recorded was not significantly altered; charge transfer resistances were increased while the capacitance of the electrochemical double layers (Double layer capacitance) as well as the concentration of dissolved iron (Fen+) ions in the environment, were all reduced with increasing concentration of the expired drug. Although moderate amounts of the expired drug delivered appreciable levels of corrosion inhibition when dissolved directly into the corrosive environment and without any pre-treatment, increased concentration of expired drug resulted in increased corrosion inhibition efficiency. The highest corrosion inhibition efficiency obtained was 97.6% and was from the acidic environment that contained 8 g/L of expired piroxicam drug. The expired piroxicam drug inhibited corrosion of mild steel in 0.5M HCl acid via spontaneous physical adsorption (physisorption) process(s), obeying Langmuir’s adsorption isotherm.
{"title":"Evaluation of Un-Preprocessed Expired Piroxicam Drug as Corrosion Inhibitor for Mild Steel in Hydrochloric Acid","authors":"Omokafe Michael, Olatunde Borode, Oyelola Oladunni Alabi, K. Alaneme, A. Adesoji","doi":"10.4028/p-dsiz01","DOIUrl":"https://doi.org/10.4028/p-dsiz01","url":null,"abstract":"Illegal disposal and recirculation of expired drugs is a global menace which can be solved by their re-utilization as corrosion inhibitors. Thus, helping to combat the current widespread corrosion-induced wastage of expensive mild steel infrastructure. The experimental investigation evaluated the capability and effectiveness of an expired drug (piroxicam) for inhibiting mild steel corrosion in blank 0.5M HCl and acidic environments containing 2 to 8 g/L of the expired drug. Spectrometry, weight loss analysis, atomic absorption spectroscopy, microscopy, polarisation and electrochemical impedance study (EIS) were employed. Analyses revealed drastic inhibition of corrosion in mild steel by expired piroxicam drug in the acid. Corrosion currents ( ) obtained at all concentrations of the expired drug were reduced in comparison to that of the uninhibited environment. The solution resistance recorded was not significantly altered; charge transfer resistances were increased while the capacitance of the electrochemical double layers (Double layer capacitance) as well as the concentration of dissolved iron (Fen+) ions in the environment, were all reduced with increasing concentration of the expired drug. Although moderate amounts of the expired drug delivered appreciable levels of corrosion inhibition when dissolved directly into the corrosive environment and without any pre-treatment, increased concentration of expired drug resulted in increased corrosion inhibition efficiency. The highest corrosion inhibition efficiency obtained was 97.6% and was from the acidic environment that contained 8 g/L of expired piroxicam drug. The expired piroxicam drug inhibited corrosion of mild steel in 0.5M HCl acid via spontaneous physical adsorption (physisorption) process(s), obeying Langmuir’s adsorption isotherm.","PeriodicalId":45925,"journal":{"name":"International Journal of Engineering Research in Africa","volume":"61 1","pages":"29 - 50"},"PeriodicalIF":0.7,"publicationDate":"2022-07-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47062599","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}
Reliability and behaviour of composite columns is influenced by many factors. This paper presents a comparative study of the reliability and performance of square composite columns under axial compression, taking into account mechanical and geometric variability. The choice is opted for metal hollow profiles filled with ordinary concrete and high-performance concrete. In this study, a mechanic-reliability model to calculate the reliability index and the probability of failure of different columns is presented. The response surface method is used to accomplish this coupling in order to describe the uncertainties in a suitable model and to study their influence for a reliability assessment. The results show that the material and geometric characteristics of the columns have a significant influence on strength and reliability. The sensitivity of the random parameters of structural reliability is assessed from the proposed method.
{"title":"Reliability Analysis and Comparative Study of Ordinary Concrete and High Performance Concrete Filled with Steel Tube under Axial Compression","authors":"Messaoudene Lydia, Nassim Kernou","doi":"10.4028/p-9h1zq6","DOIUrl":"https://doi.org/10.4028/p-9h1zq6","url":null,"abstract":"Reliability and behaviour of composite columns is influenced by many factors. This paper presents a comparative study of the reliability and performance of square composite columns under axial compression, taking into account mechanical and geometric variability. The choice is opted for metal hollow profiles filled with ordinary concrete and high-performance concrete. In this study, a mechanic-reliability model to calculate the reliability index and the probability of failure of different columns is presented. The response surface method is used to accomplish this coupling in order to describe the uncertainties in a suitable model and to study their influence for a reliability assessment. The results show that the material and geometric characteristics of the columns have a significant influence on strength and reliability. The sensitivity of the random parameters of structural reliability is assessed from the proposed method.","PeriodicalId":45925,"journal":{"name":"International Journal of Engineering Research in Africa","volume":"61 1","pages":"245 - 261"},"PeriodicalIF":0.7,"publicationDate":"2022-07-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46791655","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}
Different fines of rice husk ash (RHA) are typically used as a binder for soil stabilization. This study aims to assess the performance of RHA fines as a binder with lime in the improvement of plasticity and compaction characteristics of stabilized soil. Consistency limits, particle sieve analysis, and compaction tests were conducted on the natural lateritic soil, while consistency limits and compaction tests were conducted on the stabilized lateritic soil. The tests conformed to BS 1377 (1990). The chemical compositions of the RHA were assessed. Lateritic soil samples were mixed with lime in the proportions of 2, 4, 6, 8, and 10% by weight of dry soil. Plasticity Index (PI) was used as the determinant of optimum performance of lime-stabilized lateritic soil and this was obtained at 8% of lime addition. Thereafter, binder ratios (Lime: RHA) of 0:8, 2:6, 4:4, 6:2, and 8:0 were employed in the blending of the lateritic soil. The Plasticity Index (PI) of the stabilized soil were generally lowered to 7.82%, 21.36%, 18.97%, 19.71%, 15.03% when stabilized with BR2:675μm, BR4:475μm, BR6:275μm, BR2:6300μm and BR6:2300μm respectively. All binder ratios containing both lime and RHA size of 75 μm reduced the PI. Also, the effect of all binder ratios containing both lime and all RHA sizes showed increment in the Maximum Dry Density (MDD). Similarly, soil stabilized with BR2:6150μm, BR4:475μm, BR4:4150μm, BR4:4300μm, BR6:2150μm and BR6:2300μm offered a lowered OMC. 75μm RHA and BR4:475μm had the potential to improve Lime-RHA stabilized lateritic soil mixture especially for road application.
{"title":"Influence of Rice Husk Ash Fines on Geotechnical Properties of Lime Stabilized Lateritic Soil","authors":"F. Ayodele, B. Alo, A. Adetoro","doi":"10.4028/p-35mk32","DOIUrl":"https://doi.org/10.4028/p-35mk32","url":null,"abstract":"Different fines of rice husk ash (RHA) are typically used as a binder for soil stabilization. This study aims to assess the performance of RHA fines as a binder with lime in the improvement of plasticity and compaction characteristics of stabilized soil. Consistency limits, particle sieve analysis, and compaction tests were conducted on the natural lateritic soil, while consistency limits and compaction tests were conducted on the stabilized lateritic soil. The tests conformed to BS 1377 (1990). The chemical compositions of the RHA were assessed. Lateritic soil samples were mixed with lime in the proportions of 2, 4, 6, 8, and 10% by weight of dry soil. Plasticity Index (PI) was used as the determinant of optimum performance of lime-stabilized lateritic soil and this was obtained at 8% of lime addition. Thereafter, binder ratios (Lime: RHA) of 0:8, 2:6, 4:4, 6:2, and 8:0 were employed in the blending of the lateritic soil. The Plasticity Index (PI) of the stabilized soil were generally lowered to 7.82%, 21.36%, 18.97%, 19.71%, 15.03% when stabilized with BR2:675μm, BR4:475μm, BR6:275μm, BR2:6300μm and BR6:2300μm respectively. All binder ratios containing both lime and RHA size of 75 μm reduced the PI. Also, the effect of all binder ratios containing both lime and all RHA sizes showed increment in the Maximum Dry Density (MDD). Similarly, soil stabilized with BR2:6150μm, BR4:475μm, BR4:4150μm, BR4:4300μm, BR6:2150μm and BR6:2300μm offered a lowered OMC. 75μm RHA and BR4:475μm had the potential to improve Lime-RHA stabilized lateritic soil mixture especially for road application.","PeriodicalId":45925,"journal":{"name":"International Journal of Engineering Research in Africa","volume":"61 1","pages":"217 - 230"},"PeriodicalIF":0.7,"publicationDate":"2022-07-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44587660","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}
Cities all around the globe are ramping up efforts to transform their infrastructure in order to achieve a carbon-neutral and sustainable future, resulting in fast electrification of transportation networks. The need for power in this industry is rising, notably in light rail transit. Application of train rooftops wind energy conversion has the potential to power light rail transits with renewable energy. This research paper presents a way to generate electrical energy by utilizing strong wind pressure from light rail trains that channels the induced wind towards the turbine. The current invention's main aim is to establish a method and system for producing energy utilizing winds that can be conveniently available in the operation of trains. Here the wind energy is independent of the variations in the direction and speeds in which seasonal winds move, which do not have the appropriate wind force or force at all times or places for operating the wind turbines. Vertical axis wind turbines are selected due to their advantage for the application under consideration. SOLIDWORKS and MATLAB simulation software were used for the design of the Train Roof-Tops Wind Energy Conversion System (TRT-WECS). The former was used to perform computational fluid dynamics (CFD) on the both normal train as well as the train having a turbine installed on the top, and a comparison has been made in terms of various parameters that affect the performance of the newly designed TRT-WECS. A mathematical model comprising mechanical and electric components has been developed by using MATLAB. Finally, the study found out that this special TRT-WECS design installed in each train provides an annual energy output of 4.9 MWh.
{"title":"A Novel Train Roof-Top Wind Energy Conversion System","authors":"Asegid Kebede, G. Worku, Abreham Tibeb Maru","doi":"10.4028/p-ha82nm","DOIUrl":"https://doi.org/10.4028/p-ha82nm","url":null,"abstract":"Cities all around the globe are ramping up efforts to transform their infrastructure in order to achieve a carbon-neutral and sustainable future, resulting in fast electrification of transportation networks. The need for power in this industry is rising, notably in light rail transit. Application of train rooftops wind energy conversion has the potential to power light rail transits with renewable energy. This research paper presents a way to generate electrical energy by utilizing strong wind pressure from light rail trains that channels the induced wind towards the turbine. The current invention's main aim is to establish a method and system for producing energy utilizing winds that can be conveniently available in the operation of trains. Here the wind energy is independent of the variations in the direction and speeds in which seasonal winds move, which do not have the appropriate wind force or force at all times or places for operating the wind turbines. Vertical axis wind turbines are selected due to their advantage for the application under consideration. SOLIDWORKS and MATLAB simulation software were used for the design of the Train Roof-Tops Wind Energy Conversion System (TRT-WECS). The former was used to perform computational fluid dynamics (CFD) on the both normal train as well as the train having a turbine installed on the top, and a comparison has been made in terms of various parameters that affect the performance of the newly designed TRT-WECS. A mathematical model comprising mechanical and electric components has been developed by using MATLAB. Finally, the study found out that this special TRT-WECS design installed in each train provides an annual energy output of 4.9 MWh.","PeriodicalId":45925,"journal":{"name":"International Journal of Engineering Research in Africa","volume":"61 1","pages":"165 - 194"},"PeriodicalIF":0.7,"publicationDate":"2022-07-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42441523","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 presents parametric study of dual band notch ultra wideband (UWB) antenna using modified electromagnetic band gap. The Electromagnetic Band Gap (EBG) comprises of two strip patched and an edge-located via with respect to ground for dual notch band. The study was presented in order to have an improved knowledge of EBG characteristics and its effect on the notching band of a small squared ultra wideband antenna of size 24 by 31 mm2 dual band notch using HFSS software. The antenna operates within the return loss (s11< -10dB) 3.2 to 12.3 GHz. The simulation results show that the notched band between 4.57 – 4.99 GHz and 7.96 – 8.32 GHz corresponding to WLAN and ITU respectively was achieved. The effect of gap distance between the field line and EBG was demonstrated as well and the position of via with respect to the ground as a means for notched band centre frequency tuning. The antenna could be considered a good candidate for any UWB applications that must avoid narrow band interference. The research gives ideas on the best placement position of EBG structure along field line in UWB antenna frequency notching technique.
{"title":"Parametric Study and Analysis of Modified Electromagnetic Band Gap in Frequency Notching of Ultra-Wide Band Antenna","authors":"G. Fadehan, K. Adedeji, Y. Olasoji","doi":"10.4028/p-82d0o7","DOIUrl":"https://doi.org/10.4028/p-82d0o7","url":null,"abstract":"This paper presents parametric study of dual band notch ultra wideband (UWB) antenna using modified electromagnetic band gap. The Electromagnetic Band Gap (EBG) comprises of two strip patched and an edge-located via with respect to ground for dual notch band. The study was presented in order to have an improved knowledge of EBG characteristics and its effect on the notching band of a small squared ultra wideband antenna of size 24 by 31 mm2 dual band notch using HFSS software. The antenna operates within the return loss (s11< -10dB) 3.2 to 12.3 GHz. The simulation results show that the notched band between 4.57 – 4.99 GHz and 7.96 – 8.32 GHz corresponding to WLAN and ITU respectively was achieved. The effect of gap distance between the field line and EBG was demonstrated as well and the position of via with respect to the ground as a means for notched band centre frequency tuning. The antenna could be considered a good candidate for any UWB applications that must avoid narrow band interference. The research gives ideas on the best placement position of EBG structure along field line in UWB antenna frequency notching technique.","PeriodicalId":45925,"journal":{"name":"International Journal of Engineering Research in Africa","volume":"61 1","pages":"151 - 164"},"PeriodicalIF":0.7,"publicationDate":"2022-07-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45889878","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}
Gasification is a green technology, which produces combustible gas mixture from solid biomass by partial oxidation at elevated temperatures. Synthesis gas, the desired product of such technology, has more uses than the solid biomass. In this study, a locally developed pilot scale fixed-bed downdraft biomass gasifier was examined. Several gasification experiments using mixed wood wastes (generated from the utilisation of various wood species for making furniture) as feedstock was carried out under varied operating conditions to ascertain their effects on the syngas produced in the process. The effects of grate temperatures and biomass moisture levels on rate of biomass consumption and produced syngas quality were examined via several gasification experiments. The performance of the biomass gasifier system was evaluated in terms of syngas composition, lower heating value, syngas yield and carbon conversion efficiency. The results obtained revealed an average syngas yield of 1.77Nm3 per kg of wood waste consumed. The averaged molar syngas composition obtained was 28.15% CO, 16.64% H2, 6.19% CO2, 2.54% CH4 and 45.42% N2, while the average syngas LHV was 6.23MJ/Nm3. These results were compared with those published in literature.
气化是一种绿色技术，它通过在高温下将固体生物质部分氧化产生可燃气体混合物。合成气是这种技术的理想产物，它比固体生物质有更多的用途。在本研究中，研究了本地开发的中试规模固定床下吸式生物质气化炉。在不同的操作条件下，使用混合木材废料(利用各种木材制造家具产生)作为原料进行了几次气化实验，以确定它们对过程中产生的合成气的影响。通过几个气化实验，考察了炉排温度和生物质湿度对生物质消耗率和合成气质量的影响。从合成气组成、低热值、合成气产量和碳转化效率等方面对生物质气化炉系统的性能进行了评价。所得结果显示，每消耗一公斤木材废料，平均合成气产量为1.77Nm3。得到的平均摩尔合成气组分为CO 28.15%， H2 16.64%， CO2 6.19%， ch2 2.54%， N2 45.42%，平均LHV为6.23MJ/Nm3。这些结果与文献中发表的结果进行了比较。
{"title":"Experimental Studies on Synthesis Gas Production from Wood Wastes in a Pilot Downdraft Gasifier","authors":"P. Akhator, A. Obanor, G. Sadjere","doi":"10.4028/p-3t20w5","DOIUrl":"https://doi.org/10.4028/p-3t20w5","url":null,"abstract":"Gasification is a green technology, which produces combustible gas mixture from solid biomass by partial oxidation at elevated temperatures. Synthesis gas, the desired product of such technology, has more uses than the solid biomass. In this study, a locally developed pilot scale fixed-bed downdraft biomass gasifier was examined. Several gasification experiments using mixed wood wastes (generated from the utilisation of various wood species for making furniture) as feedstock was carried out under varied operating conditions to ascertain their effects on the syngas produced in the process. The effects of grate temperatures and biomass moisture levels on rate of biomass consumption and produced syngas quality were examined via several gasification experiments. The performance of the biomass gasifier system was evaluated in terms of syngas composition, lower heating value, syngas yield and carbon conversion efficiency. The results obtained revealed an average syngas yield of 1.77Nm3 per kg of wood waste consumed. The averaged molar syngas composition obtained was 28.15% CO, 16.64% H2, 6.19% CO2, 2.54% CH4 and 45.42% N2, while the average syngas LHV was 6.23MJ/Nm3. These results were compared with those published in literature.","PeriodicalId":45925,"journal":{"name":"International Journal of Engineering Research in Africa","volume":"61 1","pages":"115 - 128"},"PeriodicalIF":0.7,"publicationDate":"2022-07-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44846166","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}
O. Olayemi, M. Isiaka, K. Al‐Farhany, M. A. Alomari, M. Ismael, S. Oyedepo
Numerical study of natural convection around a heated trapezoidal block of different sizes located centrically in a larger trapezium has been investigated. The annulus between the trapeziums is filled with porous media. The sides of the inner trapezium are heated to a fixed temperature (T_h), and the slanted walls of the outer trapezium are adiabatic while its upper and lower walls are heated to temperatures of 〖T_c+(T_h-T_c)sin〗(πx⁄L) and 〖T_h+(T_h-T_c)sin〗(πx⁄L) respectively. The finite element numerical approach was used to solve the relevant dimensionless equations. Results are gotten for salient parameters including; modified Rayleigh number (10≤Ra_m≤ 1000), Darcy number (10^(-5)≤Da≤ 10^(-2)), and area ratio (1/5≤AR≤ 1/3). The results of this study are shown as isothermal contours, stream functions, and average Nusselt number. The results show that increasing Ra_m improves heat transfer; however, the response of thermal characteristics to AR increment depends on the range of Darcy number considered. Results from this study find application in ingot treatments and microchannel cooling among others.
{"title":"Numerical Analysis of Natural Convection in a Concentric Trapezoidal Enclosure Filled with a Porous Medium","authors":"O. Olayemi, M. Isiaka, K. Al‐Farhany, M. A. Alomari, M. Ismael, S. Oyedepo","doi":"10.4028/p-jza9vq","DOIUrl":"https://doi.org/10.4028/p-jza9vq","url":null,"abstract":"Numerical study of natural convection around a heated trapezoidal block of different sizes located centrically in a larger trapezium has been investigated. The annulus between the trapeziums is filled with porous media. The sides of the inner trapezium are heated to a fixed temperature (T_h), and the slanted walls of the outer trapezium are adiabatic while its upper and lower walls are heated to temperatures of 〖T_c+(T_h-T_c)sin〗(πx⁄L) and 〖T_h+(T_h-T_c)sin〗(πx⁄L) respectively. The finite element numerical approach was used to solve the relevant dimensionless equations. Results are gotten for salient parameters including; modified Rayleigh number (10≤Ra_m≤ 1000), Darcy number (10^(-5)≤Da≤ 10^(-2)), and area ratio (1/5≤AR≤ 1/3). The results of this study are shown as isothermal contours, stream functions, and average Nusselt number. The results show that increasing Ra_m improves heat transfer; however, the response of thermal characteristics to AR increment depends on the range of Darcy number considered. Results from this study find application in ingot treatments and microchannel cooling among others.","PeriodicalId":45925,"journal":{"name":"International Journal of Engineering Research in Africa","volume":"61 1","pages":"129 - 150"},"PeriodicalIF":0.7,"publicationDate":"2022-07-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48859996","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}
R. Zegait, Mohamed Rafik Bentraia, H. Bensaha, Mohamed Azlaoui
Many populations of isolated and rural areas around the world are facing major problems of water deficit in domestic needs, irrigation and grazing and remains the daily concern of the inhabitants and which are particularly accentuated in the arid and desert areas. In this context, several researchers have recently oriented their research to the solar system. This energy is clean and nonpolluting and its use provides an inexhaustible source of energy. Photovoltaic pumping is one of the applications of solar energy in remote sites where conventional electricity is absent, such as the Algerian Sahara, which has one of the highest solar deposits in the world which can exceed yearly 2263 kWh/m2. This solution represents the ideal technical method for supplying water from wells of groundwater. The main purpose of this work is to evaluate the reliability of solar pumping systems compared to a conventional power system applied to two experimental wells installed in an isolated pastoral region in the Algerian Sahara and precisely in the Ouargla region.The results showed that the generator pumping technique appears to be the least expensive at the beginning of the operation. The balance becomes clearly in favor of the solar pumping solution after a few years of operation (about 5 years), with a 50% benefit in the cost per cubic meter of water.
{"title":"Comparative Study of a Pumping System Using Conventional and Photovoltaic Power in the Algerian Sahara (Application to Pastoral Wells)","authors":"R. Zegait, Mohamed Rafik Bentraia, H. Bensaha, Mohamed Azlaoui","doi":"10.4028/p-6sxg2q","DOIUrl":"https://doi.org/10.4028/p-6sxg2q","url":null,"abstract":"Many populations of isolated and rural areas around the world are facing major problems of water deficit in domestic needs, irrigation and grazing and remains the daily concern of the inhabitants and which are particularly accentuated in the arid and desert areas. In this context, several researchers have recently oriented their research to the solar system. This energy is clean and nonpolluting and its use provides an inexhaustible source of energy. Photovoltaic pumping is one of the applications of solar energy in remote sites where conventional electricity is absent, such as the Algerian Sahara, which has one of the highest solar deposits in the world which can exceed yearly 2263 kWh/m2. This solution represents the ideal technical method for supplying water from wells of groundwater. The main purpose of this work is to evaluate the reliability of solar pumping systems compared to a conventional power system applied to two experimental wells installed in an isolated pastoral region in the Algerian Sahara and precisely in the Ouargla region.The results showed that the generator pumping technique appears to be the least expensive at the beginning of the operation. The balance becomes clearly in favor of the solar pumping solution after a few years of operation (about 5 years), with a 50% benefit in the cost per cubic meter of water.","PeriodicalId":45925,"journal":{"name":"International Journal of Engineering Research in Africa","volume":"60 1","pages":"63 - 74"},"PeriodicalIF":0.7,"publicationDate":"2022-05-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41749536","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}
E. K. Orhorhoro, Emmanuel E. Lindsay, J. O. Oyejide
Sub-Sahara Africa countries are faced with the problem of solid waste management and access to sustainable energy. There is a need to develop a technology that can help to manage the generated solid waste and the same time produce green energy that is sustainable. Hence, this research work that focused on the development of a novel three-stage anaerobic digestion (AD) plant for management of biodegradable portion of municipal solid waste. An experimental design and preliminary tests using co-digestion of municipal solid waste was conducted with the operation and process parameters utilized in this research work. Conceptual design was generated based on results of experimental design. The developed AD plant was evaluated for performance and the results obtained compared to an existing single stage fixed dome AD pilot plant using 100 kg of substrates with an organic loading rate of 3 kg/m3day for an operating time of 163 days. The cumulative biogas yield, and behaviour of the operation and process parameters utilized in this research work were evaluated. The results obtained reveal that unlike the single stage fixed dome AD pilot plant, the three-stage AD plant enables continuous production of biogas. Besides, optimum conditions of neutral pH range of 6.99 m to 7.01 m, slurry mesophilic temperature range of 37.05 °C to 37.15 °C, and organic loading rate of 3kg/m3d that favoured optimum biogas yield were established.
{"title":"Analysis and Evaluation of a Three-Stage Anaerobic Digestion Plant for Management of Biodegradable Municipal Solid Waste","authors":"E. K. Orhorhoro, Emmanuel E. Lindsay, J. O. Oyejide","doi":"10.4028/p-a24obb","DOIUrl":"https://doi.org/10.4028/p-a24obb","url":null,"abstract":"Sub-Sahara Africa countries are faced with the problem of solid waste management and access to sustainable energy. There is a need to develop a technology that can help to manage the generated solid waste and the same time produce green energy that is sustainable. Hence, this research work that focused on the development of a novel three-stage anaerobic digestion (AD) plant for management of biodegradable portion of municipal solid waste. An experimental design and preliminary tests using co-digestion of municipal solid waste was conducted with the operation and process parameters utilized in this research work. Conceptual design was generated based on results of experimental design. The developed AD plant was evaluated for performance and the results obtained compared to an existing single stage fixed dome AD pilot plant using 100 kg of substrates with an organic loading rate of 3 kg/m3day for an operating time of 163 days. The cumulative biogas yield, and behaviour of the operation and process parameters utilized in this research work were evaluated. The results obtained reveal that unlike the single stage fixed dome AD pilot plant, the three-stage AD plant enables continuous production of biogas. Besides, optimum conditions of neutral pH range of 6.99 m to 7.01 m, slurry mesophilic temperature range of 37.05 °C to 37.15 °C, and organic loading rate of 3kg/m3d that favoured optimum biogas yield were established.","PeriodicalId":45925,"journal":{"name":"International Journal of Engineering Research in Africa","volume":"60 1","pages":"75 - 87"},"PeriodicalIF":0.7,"publicationDate":"2022-05-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45911035","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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