Meryem Taoufiki, Hanae Chabba, Hassane Mes-Adi, A. Barroug, A. Jouaiti
The strain rate exerts a profound influence on the mechanical characteristics of nanomaterials. To investigate this phenomenon, the molecular dynamics approach was employed to examine the impact of uniaxial compression along the [100] crystallographic direction in monocrystalline Al. The purpose of this research was to determine the differences in reactions observed during the elastic and plastic phases. It employed the Embedded Atom Method (EAM) as well as the Modified Embedded Atom Method (MEAM) potentials at 300 K. A comparative analysis of the outcomes from these potentials demonstrated considerable disparities. The results encompassed the percentage distribution of crystal structures (fcc, hcp, bcc, and others) as well as their atomic configurations. Several analytical factors were examined, including the strain-stress curve, the radial distribution function (RDF), the common neighbor analysis (CAN). The applied MEAM potential represents a subsequent occurrence of transitions following EAM, encompassing both increasing and decreasing phase transitions.
应变速率对纳米材料的机械特性有着深远的影响。为了研究这一现象，我们采用了分子动力学方法来研究单晶铝沿[100]晶体学方向单轴压缩的影响。这项研究的目的是确定在弹性阶段和塑性阶段观察到的反应差异。研究采用了嵌入式原子法（EAM）和修正嵌入式原子法（MEAM）在 300 K 时的电位。结果包括晶体结构（Fcc、HCP、BCC 和其他）的分布百分比及其原子构型。研究还考察了几个分析因素，包括应变应力曲线、径向分布函数（RDF）和共邻分析（CAN）。所应用的 MEAM 电位代表了 EAM 之后发生的转变，包括增加和减少的相变。
{"title":"Microstructural Evolution of Al under Computational Analysis of Uniaxial [100] Compression","authors":"Meryem Taoufiki, Hanae Chabba, Hassane Mes-Adi, A. Barroug, A. Jouaiti","doi":"10.4028/p-famnc6","DOIUrl":"https://doi.org/10.4028/p-famnc6","url":null,"abstract":"The strain rate exerts a profound influence on the mechanical characteristics of nanomaterials. To investigate this phenomenon, the molecular dynamics approach was employed to examine the impact of uniaxial compression along the [100] crystallographic direction in monocrystalline Al. The purpose of this research was to determine the differences in reactions observed during the elastic and plastic phases. It employed the Embedded Atom Method (EAM) as well as the Modified Embedded Atom Method (MEAM) potentials at 300 K. A comparative analysis of the outcomes from these potentials demonstrated considerable disparities. The results encompassed the percentage distribution of crystal structures (fcc, hcp, bcc, and others) as well as their atomic configurations. Several analytical factors were examined, including the strain-stress curve, the radial distribution function (RDF), the common neighbor analysis (CAN). The applied MEAM potential represents a subsequent occurrence of transitions following EAM, encompassing both increasing and decreasing phase transitions.","PeriodicalId":507603,"journal":{"name":"International Journal of Engineering Research in Africa","volume":"52 2","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-05-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141114535","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}
{"title":"International Journal of Engineering Research in Africa Vol. 69","authors":"","doi":"10.4028/b-syuw31","DOIUrl":"https://doi.org/10.4028/b-syuw31","url":null,"abstract":"","PeriodicalId":507603,"journal":{"name":"International Journal of Engineering Research in Africa","volume":"82 13","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-05-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141116307","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}
Qi Li, Deng Hao Wu, De Zhi Yang, Ming Hao Fei, Yu Song, Yan Liu
With the development of automation technology, it gradually replaces manual labor in various fields. Pumps are widely used in various production processes in the industrial field. To enhance the automation level of the pump production and testing process will significantly reduce production costs. This paper aims to design and realize a set of fully automatic, high-precision pump performance testing system. The fully automated operation of the performance test is designed according to the flow rate automatic sampling method, to achieve the accurate measurement of the pump operating conditions. Utilizing the PID algorithm, the valve is automatically adjusted through PLC control to realize the accurate positioning of the flow measurement point. With the help of the software program to carry out the calculation and analysis of test data, to achieve the visualization of the test process of the whole performance test data management. At the same time, SQL Server database is used to realize rapid query and management of test data. After the test verification, the system realizes the full-automatic measurement of the pump performance curve, and the measurement accuracy conforms to the standard of ISO 9906:2012.
随着自动化技术的发展，它逐渐在各个领域取代了人工。泵广泛应用于工业领域的各个生产环节。提高泵生产和测试过程的自动化水平将大大降低生产成本。本文旨在设计并实现一套全自动、高精度的泵性能测试系统。全自动运行的性能测试按照流量自动采样方式设计，实现了对泵运行工况的精确测量。利用 PID 算法，通过 PLC 控制自动调节阀门，实现流量测量点的精确定位。借助软件程序进行测试数据的计算和分析，实现测试过程中整个性能测试数据的可视化管理。同时，利用 SQL Server 数据库实现测试数据的快速查询和管理。经过试验验证，系统实现了泵性能曲线的全自动测量，测量精度符合 ISO 9906:2012 标准。
{"title":"Design and Realization of Fully Automatic Pump Performance Test System","authors":"Qi Li, Deng Hao Wu, De Zhi Yang, Ming Hao Fei, Yu Song, Yan Liu","doi":"10.4028/p-mx1enp","DOIUrl":"https://doi.org/10.4028/p-mx1enp","url":null,"abstract":"With the development of automation technology, it gradually replaces manual labor in various fields. Pumps are widely used in various production processes in the industrial field. To enhance the automation level of the pump production and testing process will significantly reduce production costs. This paper aims to design and realize a set of fully automatic, high-precision pump performance testing system. The fully automated operation of the performance test is designed according to the flow rate automatic sampling method, to achieve the accurate measurement of the pump operating conditions. Utilizing the PID algorithm, the valve is automatically adjusted through PLC control to realize the accurate positioning of the flow measurement point. With the help of the software program to carry out the calculation and analysis of test data, to achieve the visualization of the test process of the whole performance test data management. At the same time, SQL Server database is used to realize rapid query and management of test data. After the test verification, the system realizes the full-automatic measurement of the pump performance curve, and the measurement accuracy conforms to the standard of ISO 9906:2012.","PeriodicalId":507603,"journal":{"name":"International Journal of Engineering Research in Africa","volume":"67 3","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-05-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141114050","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}
Space heating and cooling using geothermal heat exchangers is a promising environmentally friendly green energy solution. Modeling these energy storage systems is crucial for optimizing their design and operation. In this context, the present study consists of numerically investigating the effects of various physical properties, including thermal conductivity, density, and specific heat capacity of each material, as well as flow velocity, on the process of heat transfer in vertical geothermal heat exchangers using coaxial pipes to optimize their energy performance. Numerical simulations were carried out using Gambit-Fluent software. Different materials that make up the coaxial heat exchanger structure studied were tested to highlight their effects on the progress of heat flux and temperature. Thermal and fluid mechanics aspects were also studied. At the end of this study, a comparative analysis was carried out using the U-tube geothermal heat exchanger. The results indicate that the heat exchanger using a coaxial tube demonstrates superior thermal efficiency compared to the U-tube configuration. It has been found that using a low velocity with an appropriate selection of tube, grout, and soil materials results in enhanced dynamic exchanges, thereby enhancing the thermal efficiency of the geothermal exchanger.
利用地热热交换器进行空间供暖和制冷是一种前景广阔的环保型绿色能源解决方案。这些储能系统的建模对于优化其设计和运行至关重要。在此背景下，本研究以数值方法研究了各种物理特性（包括每种材料的热导率、密度和比热容以及流速）对使用同轴管的垂直地热换热器传热过程的影响，以优化其能源性能。数值模拟使用 Gambit-Fluent 软件进行。对构成所研究的同轴热交换器结构的不同材料进行了测试，以突出它们对热通量和温度变化的影响。此外，还研究了热力学和流体力学方面的问题。研究结束时，使用 U 型管地热换热器进行了对比分析。结果表明，与 U 型管结构相比，使用同轴管的热交换器具有更高的热效率。研究发现，在适当选择管材、灌浆材料和土壤材料的情况下，使用低流速可增强动态交换，从而提高地热交换器的热效率。
{"title":"Numerical Investigation of the Coaxial Geothermal Heat Exchanger Performance","authors":"M. Benyoub, B. Aour, A. Oudrane, K. Sadek","doi":"10.4028/p-6ovlez","DOIUrl":"https://doi.org/10.4028/p-6ovlez","url":null,"abstract":"Space heating and cooling using geothermal heat exchangers is a promising environmentally friendly green energy solution. Modeling these energy storage systems is crucial for optimizing their design and operation. In this context, the present study consists of numerically investigating the effects of various physical properties, including thermal conductivity, density, and specific heat capacity of each material, as well as flow velocity, on the process of heat transfer in vertical geothermal heat exchangers using coaxial pipes to optimize their energy performance. Numerical simulations were carried out using Gambit-Fluent software. Different materials that make up the coaxial heat exchanger structure studied were tested to highlight their effects on the progress of heat flux and temperature. Thermal and fluid mechanics aspects were also studied. At the end of this study, a comparative analysis was carried out using the U-tube geothermal heat exchanger. The results indicate that the heat exchanger using a coaxial tube demonstrates superior thermal efficiency compared to the U-tube configuration. It has been found that using a low velocity with an appropriate selection of tube, grout, and soil materials results in enhanced dynamic exchanges, thereby enhancing the thermal efficiency of the geothermal exchanger.","PeriodicalId":507603,"journal":{"name":"International Journal of Engineering Research in Africa","volume":"21 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-05-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141117678","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}
Oumaima Kanibou, Omkaltoume El Fatni, A. Maftouh, El Houssaine El Rhaleb, M. Bargach
Active daylighting technology, encompassing techniques for utilizing natural light without converting it into heat or electrical energy, proves highly beneficial in sun-rich countries like Morocco. Unlike solar technologies, which capture global radiation, daylighting technology specifically leverages direct sun radiation. This study focuses on three semi-empirical models: Perrin de Brichambaut, Kasten, and Ghouard, utilizing data from the PVGIS website to develop and evaluate these systems. Comparison of experimentally obtained direct normal irradiation results against these models and the PVGIS website identifies the Kasten model as the most suitable choice, supported by the high R2 values of 0.9954, 0.9933, 0.9951, and 0.9906 for winter, spring, summer, and autumn, respectively. Furthermore, the model exhibits a minimum Mean Absolute Error (MAE) of 12.34, 24.29, 25.93, and 29.51 W/m², an optimal Mean Squared Error (MSE) of 238.16, 1129.5, 1039.9, and 1520.7 W²/m⁴, and a variance of 216.40, 1099.3, 1015.4, and 1460 for the respective seasons. These results strongly indicate the Kasten model's suitability for the climatic conditions of the studied site in Morocco, showcasing high correlation coefficients and low prediction errors. The findings underscore the Kasten model as the most fitting choice for optimizing active daylighting technology in Morocco's climate.
{"title":"Comparisons of Direct Normal Irradiation for the Optimization of Active Daylighting Systems","authors":"Oumaima Kanibou, Omkaltoume El Fatni, A. Maftouh, El Houssaine El Rhaleb, M. Bargach","doi":"10.4028/p-hjdy4u","DOIUrl":"https://doi.org/10.4028/p-hjdy4u","url":null,"abstract":"Active daylighting technology, encompassing techniques for utilizing natural light without converting it into heat or electrical energy, proves highly beneficial in sun-rich countries like Morocco. Unlike solar technologies, which capture global radiation, daylighting technology specifically leverages direct sun radiation. This study focuses on three semi-empirical models: Perrin de Brichambaut, Kasten, and Ghouard, utilizing data from the PVGIS website to develop and evaluate these systems. Comparison of experimentally obtained direct normal irradiation results against these models and the PVGIS website identifies the Kasten model as the most suitable choice, supported by the high R2 values of 0.9954, 0.9933, 0.9951, and 0.9906 for winter, spring, summer, and autumn, respectively. Furthermore, the model exhibits a minimum Mean Absolute Error (MAE) of 12.34, 24.29, 25.93, and 29.51 W/m², an optimal Mean Squared Error (MSE) of 238.16, 1129.5, 1039.9, and 1520.7 W²/m⁴, and a variance of 216.40, 1099.3, 1015.4, and 1460 for the respective seasons. These results strongly indicate the Kasten model's suitability for the climatic conditions of the studied site in Morocco, showcasing high correlation coefficients and low prediction errors. The findings underscore the Kasten model as the most fitting choice for optimizing active daylighting technology in Morocco's climate.","PeriodicalId":507603,"journal":{"name":"International Journal of Engineering Research in Africa","volume":"17 15","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-05-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141118318","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}
Bouraida El Yamouni, Fadoua El Khannoussi, A. Khamlichi
In the seismic design of flexible cantilever walls retaining cohesive backfill soil, the common practice is to neglect the cohesion effect. Dynamic lateral earth pressure is typically evaluated based on approaches primarily intended for cohesionless soils or through analytical pseudo-static methods. Nevertheless, both experimental and theoretical evidence has demonstrated significant effects due to soil cohesion that are not accounted for by these methods. This study involved finite element modeling (FE) of a flexible cantilever wall with a height of 5.4m, supporting homogeneous cohesive backfill under initial static and seismic loadings. The calculated active earth thrust was then compared with values obtained experimentally and through conventional analytical methods. The obtained results indicate that the presence of soil cohesion significantly reduces seismic demands on flexible cantilever retaining walls, resulting in a substantial reduction of seismic active earth pressures and total seismic thrust by up to 50% and 52%, respectively. It enhances also the overall stability of the system by shifting the point of application of seismic thrust toward the base of the wall, thereby increasing the safety margin. In addition, it significantly decreases the wall displacement at the stem top, with reductions of up to 104% compared with the case involving cohesionless backfill. It was observed that the conventional methods recommended by some seismic regulations largely underestimate seismic active pressure.
{"title":"Numerical Investigation of Seismic Behaviour for a Flexible Cantilever Retaining Wall with Cohesive Backfill","authors":"Bouraida El Yamouni, Fadoua El Khannoussi, A. Khamlichi","doi":"10.4028/p-z3wylg","DOIUrl":"https://doi.org/10.4028/p-z3wylg","url":null,"abstract":"In the seismic design of flexible cantilever walls retaining cohesive backfill soil, the common practice is to neglect the cohesion effect. Dynamic lateral earth pressure is typically evaluated based on approaches primarily intended for cohesionless soils or through analytical pseudo-static methods. Nevertheless, both experimental and theoretical evidence has demonstrated significant effects due to soil cohesion that are not accounted for by these methods. This study involved finite element modeling (FE) of a flexible cantilever wall with a height of 5.4m, supporting homogeneous cohesive backfill under initial static and seismic loadings. The calculated active earth thrust was then compared with values obtained experimentally and through conventional analytical methods. The obtained results indicate that the presence of soil cohesion significantly reduces seismic demands on flexible cantilever retaining walls, resulting in a substantial reduction of seismic active earth pressures and total seismic thrust by up to 50% and 52%, respectively. It enhances also the overall stability of the system by shifting the point of application of seismic thrust toward the base of the wall, thereby increasing the safety margin. In addition, it significantly decreases the wall displacement at the stem top, with reductions of up to 104% compared with the case involving cohesionless backfill. It was observed that the conventional methods recommended by some seismic regulations largely underestimate seismic active pressure.","PeriodicalId":507603,"journal":{"name":"International Journal of Engineering Research in Africa","volume":"73 8","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-05-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141116757","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}
Mohamed S. Melad, M. A. Gebril, Farag Shuaeib, Rafaa M. Esmaael, Mohamed A. El-Hag
The aim of this work is to examine and analyze, using response surface methodology, how the TIG welding process parameters of welding current (WC), welding speed (WS), and N2 with argon as shielding gas affect the hardness and corrosion resistance of 2205 DSS weldments. Due to the equal amounts of ferrite and austenite phases and alloying elements, duplex stainless steel DSS offers good mechanical properties and corrosion resistance. The mechanical characteristics and resistance to corrosion of the weld zone, as well as the heat-affected zone of the DSS, are, however, disturbed as a result of the welding process since it changes the distribution of these two phases and also the alloy is thermally disturbed. Therefore, in this work, an in-depth investigation of the effects of the above-mentioned parameters on the DSS quality has been performed. Results showed that increasing welding current while decreasing welding speed, which corresponds to the highest heat input, led to lower critical pitting potential and weld zone hardness but higher heat-affected zone hardness. The same results were obtained for decreasing welding current while increasing welding speed, which correspond to the lowest heat input. However, the addition of a small percent (%) of N2 to argon shielding gas resulted in increasing the critical pitting potential and decreasing the hardness in welds and heat-affected zones. Numerically, the RSM planned experimental results showed that an optimum welding current of 175A, welding speed of 170 mm/min, and 10% N2 with argon as shielding gas maximized the critical pitting potential up to 318 mV and optimized the hardness of the weld and heat-affected zone to about base metal hardness of 288 and 286 HV, respectively.
{"title":"An In-Depth Investigation of the Effects of Tungsten Inert Gas Welding Process Parameters on Hardness and Corrosion Resistance of 2205 DSS Weldments: New Design of Experiment Parametric Studies and Optimization","authors":"Mohamed S. Melad, M. A. Gebril, Farag Shuaeib, Rafaa M. Esmaael, Mohamed A. El-Hag","doi":"10.4028/p-mhdf4l","DOIUrl":"https://doi.org/10.4028/p-mhdf4l","url":null,"abstract":"The aim of this work is to examine and analyze, using response surface methodology, how the TIG welding process parameters of welding current (WC), welding speed (WS), and N2 with argon as shielding gas affect the hardness and corrosion resistance of 2205 DSS weldments. Due to the equal amounts of ferrite and austenite phases and alloying elements, duplex stainless steel DSS offers good mechanical properties and corrosion resistance. The mechanical characteristics and resistance to corrosion of the weld zone, as well as the heat-affected zone of the DSS, are, however, disturbed as a result of the welding process since it changes the distribution of these two phases and also the alloy is thermally disturbed. Therefore, in this work, an in-depth investigation of the effects of the above-mentioned parameters on the DSS quality has been performed. Results showed that increasing welding current while decreasing welding speed, which corresponds to the highest heat input, led to lower critical pitting potential and weld zone hardness but higher heat-affected zone hardness. The same results were obtained for decreasing welding current while increasing welding speed, which correspond to the lowest heat input. However, the addition of a small percent (%) of N2 to argon shielding gas resulted in increasing the critical pitting potential and decreasing the hardness in welds and heat-affected zones. Numerically, the RSM planned experimental results showed that an optimum welding current of 175A, welding speed of 170 mm/min, and 10% N2 with argon as shielding gas maximized the critical pitting potential up to 318 mV and optimized the hardness of the weld and heat-affected zone to about base metal hardness of 288 and 286 HV, respectively.","PeriodicalId":507603,"journal":{"name":"International Journal of Engineering Research in Africa","volume":"5 6","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-05-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141114122","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 describes a comparative performance analysis of sliding mode and fuzzy sliding mode controllers for climate control application of a greenhouse flower garden. Various internal and external climate related factors affect the overall growth and health of flowers that needs robust controllers to control the humidity and temperature of the greenhouse flower garden. Review of related works show that for non-linear systems, sliding mode controllers can provide robust performance even though chattering is a major drawback of the controller. A number of approaches are used to solve the chattering problem of sliding mode controllers such as hybrid uses of other controllers along with sliding mode controller. In this paper, sliding mode controller and fuzzy sliding mode controllers are designed and implemented for the specified control application based on the linearized and decoupled model of the system. The performance evaluation has been done for the control problems of reference tracking and disturbance rejection with time domain performance measures of percentage overshoot, settling time and rise time. Accordingly, the overall system has been implemented in MATLAB/Simulink and the simulations for the control problems have been done. Thus, FSMC has got rise time of 5.89min, 10.59min settling time and almost negligible percentage overshoot for indoor temperature at 27°C and humidity at 22g/m3. And for humidity control, the FSMC has got 5.44min settling time and nearly zero percentage overshoot for set point tracking problem. For the disturbance of solar radiation, decrease in outside temperature and fixed set point of 27°C and humidity of 22g/m3, FSMC outperforms SMC. In summary, both quantitative and qualitative results analysis results reveal that fuzzy sliding mode controller (FSMC) outperforms sliding mode controller (SMC) for the indoor temperature and humidity control tasks of both set point tracking and disturbance rejection problems.
{"title":"A Comparative Analysis of Sliding Mode and Fuzzy Sliding Mode Controllers for Climate Control Application of a Greenhouse Flower Garden","authors":"T. T. Yetayew, Ermias A. Tamir, G. L. Hailu","doi":"10.4028/p-hvn4iu","DOIUrl":"https://doi.org/10.4028/p-hvn4iu","url":null,"abstract":"This paper describes a comparative performance analysis of sliding mode and fuzzy sliding mode controllers for climate control application of a greenhouse flower garden. Various internal and external climate related factors affect the overall growth and health of flowers that needs robust controllers to control the humidity and temperature of the greenhouse flower garden. Review of related works show that for non-linear systems, sliding mode controllers can provide robust performance even though chattering is a major drawback of the controller. A number of approaches are used to solve the chattering problem of sliding mode controllers such as hybrid uses of other controllers along with sliding mode controller. In this paper, sliding mode controller and fuzzy sliding mode controllers are designed and implemented for the specified control application based on the linearized and decoupled model of the system. The performance evaluation has been done for the control problems of reference tracking and disturbance rejection with time domain performance measures of percentage overshoot, settling time and rise time. Accordingly, the overall system has been implemented in MATLAB/Simulink and the simulations for the control problems have been done. Thus, FSMC has got rise time of 5.89min, 10.59min settling time and almost negligible percentage overshoot for indoor temperature at 27°C and humidity at 22g/m3. And for humidity control, the FSMC has got 5.44min settling time and nearly zero percentage overshoot for set point tracking problem. For the disturbance of solar radiation, decrease in outside temperature and fixed set point of 27°C and humidity of 22g/m3, FSMC outperforms SMC. In summary, both quantitative and qualitative results analysis results reveal that fuzzy sliding mode controller (FSMC) outperforms sliding mode controller (SMC) for the indoor temperature and humidity control tasks of both set point tracking and disturbance rejection problems.","PeriodicalId":507603,"journal":{"name":"International Journal of Engineering Research in Africa","volume":"13 5","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-05-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141114373","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}
D. Gaagaia, N. Boutasseta, K. Belkaid, B. Boubir, H. Aouaichia, Tahar Temam Guettaf, Youssouf Yaklef
The objective of this work is to carry out a comparison of different materials in the form of a bidirectional carbon fabric and hybrid Kevlar and glass as reinforcements in an epoxy matrix with a loading rate of 30wt%. Two experimental tests have been carried out in order to determine the mechanical properties, such as tensile and Brinell hardness tests. In the case of tensile and Brinell hardness tests, the characterization was performed on two types of composite plates reinforced with Woven Carbon Fiber and Hybrid Woven Kevlar and E-Glass with Epoxy (WCF-HWKG/EPOXY) and Hybrid Woven Kevlar and E-Glass with Epoxy (HWKG/EPOXY). Consequently, it has been observed that the tensile and hardness properties of the hybrid composite material (HWKG/EPOXY) are respectively 36% and 46.43% lower compared to (WCF-HWKG/EPOXY). Based on these findings, the studied materials demonstrate potential applications across various fields, including aeronautics, aerospace, and high-performance automotive sectors.
{"title":"Comparative Study of the Mechanical Properties of a Novel Epoxy Composite Material Reinforced by Bidirectional Woven Carbon Fabric and Hybrid Kevlar/E-Glass","authors":"D. Gaagaia, N. Boutasseta, K. Belkaid, B. Boubir, H. Aouaichia, Tahar Temam Guettaf, Youssouf Yaklef","doi":"10.4028/p-xz0lis","DOIUrl":"https://doi.org/10.4028/p-xz0lis","url":null,"abstract":"The objective of this work is to carry out a comparison of different materials in the form of a bidirectional carbon fabric and hybrid Kevlar and glass as reinforcements in an epoxy matrix with a loading rate of 30wt%. Two experimental tests have been carried out in order to determine the mechanical properties, such as tensile and Brinell hardness tests. In the case of tensile and Brinell hardness tests, the characterization was performed on two types of composite plates reinforced with Woven Carbon Fiber and Hybrid Woven Kevlar and E-Glass with Epoxy (WCF-HWKG/EPOXY) and Hybrid Woven Kevlar and E-Glass with Epoxy (HWKG/EPOXY). Consequently, it has been observed that the tensile and hardness properties of the hybrid composite material (HWKG/EPOXY) are respectively 36% and 46.43% lower compared to (WCF-HWKG/EPOXY). Based on these findings, the studied materials demonstrate potential applications across various fields, including aeronautics, aerospace, and high-performance automotive sectors.","PeriodicalId":507603,"journal":{"name":"International Journal of Engineering Research in Africa","volume":"75 13","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-05-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141116583","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}
H. Achiban, Hamid Achiban, A. Taous, Rachid Addou, Ismail Mansourie
Rivers play a vital role in our ecosystems, providing fresh water, supporting rich biodiversity, and contributing to human well-being. However, in the face of climate change and intensive human activities, the sediment load in rivers can reach critical levels, presenting a complex set of challenges that require immediate action. The increased sediment load can alter aquatic habitats, clog channels, reduce reservoir storage capacity, and increase the risk of flooding. These direct threats entail high costs in terms of material and ecological damage, loss of life, and expenditure on rebuilding damaged infrastructure. The quantification of bedload in watercourses is therefore crucial for maintaining water and soil resources, safeguarding riparian communities, and preserving ecological balance. The study reports the findings of a three-year monitoring of the bed load of Skhirate Wadi, a river that drains a part of the western Moroccan Meseta. The study used the colorimetric monitoring method, which quantifies the volumes of coarse sediment that were transported by monitoring topographic variations in the riverbed and measuring the distances covered by the sediment. The study showed the sediment was found to move around seven times annually on average. However, the frequency and magnitude of floods and the size of particles affect the variation in this displacement. It also showed sediments travel an average distance ranging from 649 to 883 meters per year, and that the average specific bedload at the watershed scale is 30 m3/ Km2/ year. Relationships between flood peaks mobilized sediment volumes, and average particle distances are established and discussed. These results are fundamental to understanding of coarse sediment transfer processes in the small rivers of the central plateau. They are also essential for assessing the impact on the aquatic ecosystem, on downstream dams, and on the various existing road and hydro-agricultural infrastructures. This assessment will enable the implementation of appropriate management strategies to anticipate changes and plan the planning of the river and its watershed.
{"title":"Quantification of Bed Load Transport in the Northern Part of the Central Plateau of Morocco: Case of Wadi Skhirate","authors":"H. Achiban, Hamid Achiban, A. Taous, Rachid Addou, Ismail Mansourie","doi":"10.4028/p-yz8vsx","DOIUrl":"https://doi.org/10.4028/p-yz8vsx","url":null,"abstract":"Rivers play a vital role in our ecosystems, providing fresh water, supporting rich biodiversity, and contributing to human well-being. However, in the face of climate change and intensive human activities, the sediment load in rivers can reach critical levels, presenting a complex set of challenges that require immediate action. The increased sediment load can alter aquatic habitats, clog channels, reduce reservoir storage capacity, and increase the risk of flooding. These direct threats entail high costs in terms of material and ecological damage, loss of life, and expenditure on rebuilding damaged infrastructure. The quantification of bedload in watercourses is therefore crucial for maintaining water and soil resources, safeguarding riparian communities, and preserving ecological balance. The study reports the findings of a three-year monitoring of the bed load of Skhirate Wadi, a river that drains a part of the western Moroccan Meseta. The study used the colorimetric monitoring method, which quantifies the volumes of coarse sediment that were transported by monitoring topographic variations in the riverbed and measuring the distances covered by the sediment. The study showed the sediment was found to move around seven times annually on average. However, the frequency and magnitude of floods and the size of particles affect the variation in this displacement. It also showed sediments travel an average distance ranging from 649 to 883 meters per year, and that the average specific bedload at the watershed scale is 30 m3/ Km2/ year. Relationships between flood peaks mobilized sediment volumes, and average particle distances are established and discussed. These results are fundamental to understanding of coarse sediment transfer processes in the small rivers of the central plateau. They are also essential for assessing the impact on the aquatic ecosystem, on downstream dams, and on the various existing road and hydro-agricultural infrastructures. This assessment will enable the implementation of appropriate management strategies to anticipate changes and plan the planning of the river and its watershed.","PeriodicalId":507603,"journal":{"name":"International Journal of Engineering Research in Africa","volume":"102 12","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-05-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141115851","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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