The granulometric composition of the metal/scale suspensions formed at electroerosive machining (EEM) of metal items made of the ST-10 steel has been determined to evaluate the need for a flocculant for the suspension particles extraction and decontamination of the machining working fluid. Even though most suspension particles are large enough and quickly self-precipitate, some particles are too small (sized 6 µm or less) and form quite stable suspensions, requiring additional flocculants to be extracted. Pure polyacrylamide with a molecular weight of 4-5*106 atomic units and an anionic polymer flocculant BESFLOC-4041 were considered as decontamination agents for the metal/scale suspensions. It was found that the latter agent is more effective, and it ensures the effective decontamination of an EEM working fluid. An admixture of 0.05 g/L of BESFLOC-4041 ensures effective clarification (with the decontamination efficiency of 90-95 %) of the metal/scale suspension with a dispersed phase concentration of up to 1.0 g/L. The flocculation efficiency of polyacrylamimde is lower (67-85 %) and its best performance is achieved at the concentration of 0.08 g/L.
{"title":"Cleaning the Electroerosive Machining Wastewater with some Polyacrylamide-Based Flocculants","authors":"S. Boruk, Igor Winkler","doi":"10.4028/p-dug5na","DOIUrl":"https://doi.org/10.4028/p-dug5na","url":null,"abstract":"The granulometric composition of the metal/scale suspensions formed at electroerosive machining (EEM) of metal items made of the ST-10 steel has been determined to evaluate the need for a flocculant for the suspension particles extraction and decontamination of the machining working fluid. Even though most suspension particles are large enough and quickly self-precipitate, some particles are too small (sized 6 µm or less) and form quite stable suspensions, requiring additional flocculants to be extracted. Pure polyacrylamide with a molecular weight of 4-5*106 atomic units and an anionic polymer flocculant BESFLOC-4041 were considered as decontamination agents for the metal/scale suspensions. It was found that the latter agent is more effective, and it ensures the effective decontamination of an EEM working fluid. An admixture of 0.05 g/L of BESFLOC-4041 ensures effective clarification (with the decontamination efficiency of 90-95 %) of the metal/scale suspension with a dispersed phase concentration of up to 1.0 g/L. The flocculation efficiency of polyacrylamimde is lower (67-85 %) and its best performance is achieved at the concentration of 0.08 g/L.","PeriodicalId":7184,"journal":{"name":"Advanced Engineering Forum","volume":"56 30","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141804760","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}
Reliable approximations for breach parameters using a parametric model due to embankment dam failure are very significant factors in dam safety and mitigation measures. Therefore, utilizing information on historically unsuccessful embankment dams, several empirical models have been formulated by different researchers. There is still no universal method for calculating the occurrence of dam breaches. The main objective of this research is to evaluate and compare the selected parametric dam breach models that are available in the literature. Four models (Xu et al., Vescher et al., Froehlich, and USB Reclamation) were chosen to forecast the breach event's parameters and peak discharges. Historically, 59 failed embankment dams’ data in various countries around the world were used. In order to assess and compare the breach models and recommend the best-performing model for predicting the peak discharge, breach width, and failure time, ten (10) statistical quantitative indicators were used. The breach model developed by Xu et al. has good performance. Finally, to show the impacts of erodibility, validation, and sensitivity of the selected model, it was checked using eight dams’ data. During the validation, the calculated and observed results were in agreement. Sensitivity revealed that large fluctuations in the breach parameter and peak discharge were seen when the erodibility coefficient increased or decreased.
利用参数模型对堤坝溃决引起的溃口参数进行可靠的近似计算，是大坝安全和减灾措施中非常重要的因素。因此，不同的研究人员利用历史上未成功溃坝的信息，制定了若干经验模型。目前还没有一种通用的方法来计算溃坝的发生率。本研究的主要目的是评估和比较文献中选定的参数溃坝模型。我们选择了四个模型（Xu 等人、Vescher 等人、Froehlich 和 USB Reclamation）来预测溃坝事件的参数和峰值排水量。使用了世界各国 59 座溃坝的历史数据。为了评估和比较溃坝模型，并推荐预测峰值排水量、溃坝宽度和溃坝时间的最佳模型，使用了十（10）个统计量化指标。Xu 等人开发的决口模型性能良好。最后，为了说明所选模型的可侵蚀性、验证性和灵敏度的影响，使用八个大坝的数据对其进行了检验。在验证过程中，计算结果与观测结果一致。灵敏度表明，当侵蚀系数增大或减小时，溃口参数和峰值排水量会出现较大波动。
{"title":"Evaluation and Comparison of Breach Parametric Model for Embankment Dams","authors":"Getachew Bereta Geremew","doi":"10.4028/p-z42x2n","DOIUrl":"https://doi.org/10.4028/p-z42x2n","url":null,"abstract":"Reliable approximations for breach parameters using a parametric model due to embankment dam failure are very significant factors in dam safety and mitigation measures. Therefore, utilizing information on historically unsuccessful embankment dams, several empirical models have been formulated by different researchers. There is still no universal method for calculating the occurrence of dam breaches. The main objective of this research is to evaluate and compare the selected parametric dam breach models that are available in the literature. Four models (Xu et al., Vescher et al., Froehlich, and USB Reclamation) were chosen to forecast the breach event's parameters and peak discharges. Historically, 59 failed embankment dams’ data in various countries around the world were used. In order to assess and compare the breach models and recommend the best-performing model for predicting the peak discharge, breach width, and failure time, ten (10) statistical quantitative indicators were used. The breach model developed by Xu et al. has good performance. Finally, to show the impacts of erodibility, validation, and sensitivity of the selected model, it was checked using eight dams’ data. During the validation, the calculated and observed results were in agreement. Sensitivity revealed that large fluctuations in the breach parameter and peak discharge were seen when the erodibility coefficient increased or decreased.","PeriodicalId":7184,"journal":{"name":"Advanced Engineering Forum","volume":"9 11","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141803198","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 discusses the coal-fired power plants (CFPPs) in the Southern African Development Community (SADC), in the context of the net-zero by 2050 initiative. It describes recent global climate change responses impacting the operation of CFPPs, and the medium-to-long term prospects for coal power. The paper then discusses the motivators and strategies for sustaining the operations of CFPPs in SADC, and why the international community has to let countries in the region and other small developing nations, transition to renewable energies at a more measured pace. It also offers actionable insights on sustainable financing options for upgrading the region’s CFPPs and just energy transitions. Following a balanced assessment of the facts and broad issues discussed herein including the United Nations Sustainable Development Goals 7, 10, 13, and 17; the paper concludes that most of the CFPPs in SADC are likely to remain operational way beyond the phase out deadlines despite lacking emissions abatement technologies. The pressing and burgeoning need for electricity and the huge coal reserves in the region are the determinants, rather than international norms or political correctness. However, no development institution or major country will finance any new CFPP projects in SADC, but renewable energy projects instead. Thus, national energy policymakers and power utilities in the region are recommended to revise the current energy policies to include renewable energy expansion and obliterate any mentions of proposed or planned CFPPs. SADC governments need to engage in public dissemination campaigns about the impending energy transition implications for all citizens and map out pragmatic cushioning strategies. Concurrently, they need to support innovations and entrepreneurship in renewable energies and work on improving national creditworthiness scores, to attract climate finance.
{"title":"Implications of the Global Race to Net-Zero by 2050 for the Strategic Fleet of Coal-Fired Power Plants in SADC","authors":"Melvin M. Mashingaidze","doi":"10.4028/p-lgej0b","DOIUrl":"https://doi.org/10.4028/p-lgej0b","url":null,"abstract":"This paper discusses the coal-fired power plants (CFPPs) in the Southern African Development Community (SADC), in the context of the net-zero by 2050 initiative. It describes recent global climate change responses impacting the operation of CFPPs, and the medium-to-long term prospects for coal power. The paper then discusses the motivators and strategies for sustaining the operations of CFPPs in SADC, and why the international community has to let countries in the region and other small developing nations, transition to renewable energies at a more measured pace. It also offers actionable insights on sustainable financing options for upgrading the region’s CFPPs and just energy transitions. Following a balanced assessment of the facts and broad issues discussed herein including the United Nations Sustainable Development Goals 7, 10, 13, and 17; the paper concludes that most of the CFPPs in SADC are likely to remain operational way beyond the phase out deadlines despite lacking emissions abatement technologies. The pressing and burgeoning need for electricity and the huge coal reserves in the region are the determinants, rather than international norms or political correctness. However, no development institution or major country will finance any new CFPP projects in SADC, but renewable energy projects instead. Thus, national energy policymakers and power utilities in the region are recommended to revise the current energy policies to include renewable energy expansion and obliterate any mentions of proposed or planned CFPPs. SADC governments need to engage in public dissemination campaigns about the impending energy transition implications for all citizens and map out pragmatic cushioning strategies. Concurrently, they need to support innovations and entrepreneurship in renewable energies and work on improving national creditworthiness scores, to attract climate finance.","PeriodicalId":7184,"journal":{"name":"Advanced Engineering Forum","volume":"66 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141802383","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The study explores the creation of a simulator for addressing the problem of predicting response of Nigeria’s Kainji’s Hydro Power Plant (KHPP) to system load variations and to determine parameters for stable operation. A virtual KHPP Simulation Model was designed and created using MatLab/Simulink software. The components of the HSS designed and incorporated in the virtual simulator include models of all eight (8) generating units (GUs). Each GU model consists of the Hydraulic Turbine Governor (PID), synchronous generator and an excitation system. The simulator was tested with steady state stability (SSS) and transient stability (TS) disturbances to obtain response values of system operating state parameters. The tests include a variable load increase, and three-phase short circuit fault for a duration of 0.2 s. The SSS limits established are the following: active load – 810 MW, load angle – 850, terminal voltage 0.68 pu, rotor speed 1.08 pu, excitation voltage 1.55 pu, and stator current 7.5 pu. TS limits established are load angle (1700), terminal voltage (0.60 pu), rotor speed (1.05) pu, excitation voltage (1.25 pu), stator current (7.1 pu), and critical clearing time (0.2s). Clearing time should be set at 0.2s to prevent KHPP and connected system’s instability.
{"title":"Modelling Steady State and Transient Stability Parameters for Kainji Hydropower Station, Nigeria","authors":"John O. Onimisi, A. Melodi, M. R. Adu","doi":"10.4028/p-p7snnz","DOIUrl":"https://doi.org/10.4028/p-p7snnz","url":null,"abstract":"The study explores the creation of a simulator for addressing the problem of predicting response of Nigeria’s Kainji’s Hydro Power Plant (KHPP) to system load variations and to determine parameters for stable operation. A virtual KHPP Simulation Model was designed and created using MatLab/Simulink software. The components of the HSS designed and incorporated in the virtual simulator include models of all eight (8) generating units (GUs). Each GU model consists of the Hydraulic Turbine Governor (PID), synchronous generator and an excitation system. The simulator was tested with steady state stability (SSS) and transient stability (TS) disturbances to obtain response values of system operating state parameters. The tests include a variable load increase, and three-phase short circuit fault for a duration of 0.2 s. The SSS limits established are the following: active load – 810 MW, load angle – 850, terminal voltage 0.68 pu, rotor speed 1.08 pu, excitation voltage 1.55 pu, and stator current 7.5 pu. TS limits established are load angle (1700), terminal voltage (0.60 pu), rotor speed (1.05) pu, excitation voltage (1.25 pu), stator current (7.1 pu), and critical clearing time (0.2s). Clearing time should be set at 0.2s to prevent KHPP and connected system’s instability.","PeriodicalId":7184,"journal":{"name":"Advanced Engineering Forum","volume":"4 4","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141804693","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. Ouédraogo, B. Kaboré, G. Ouedraogo, Kalifa Palm, D. Bahiebo
Substantial losses occur during the storage of onion bulbs due to the inadequacy of available preservation technologies. In an endeavor to contribute to a solution, we evaluate the thermal efficacy of a bioclimatic innovation known as the "solar cell" for onion bulb preservation. This assessment involves recording temperature data from both external and internal walls, as well as indoor and outdoor air temperatures, solar irradiation, and relative humidity levels indoors. These measurements offer insights into crucial performance parameters such as thermal phase shift, thermal inertia, thermal decoupling between internal and external environments, relative humidity, damping factor, and thermal amplitude. Furthermore, we examine the impact of external factors, including external temperature and solar radiation. Across different facades, the thermal phase shift of the chamber's structure averages between 5.5 and 10.87 hours. Notably, the maximum thermal phase shift is observed to be 11.67 hours on the Eastern wall. The lowest recorded thermal damping factor is 0.081 on the Western wall, while the highest is 0.337 on the Northern wall. The study of thermal decoupling between the internal and external environments reveals a potential temperature differential of 13.7°C and 9.5°C during the day, and-6°C at night, contingent on the time of year. Consequently, the "close or open" operational mode proves to be of significant interest. Exposed to solar radiation peaking at 1041 W/m2, the temperatures of the external facades of the walls experience a substantial increase, reaching up to 52.3°C. Meanwhile, the internal environment maintains a thermal range of 24.21°C to 31.68°C under a maximum airflow of 0.18 m/s. The average relative humidity within the storage chamber fluctuates between 42.65% and 87%. Hence, the solar cell demonstrates its capacity to create optimal conditions of 25°C-30°C and 0.062 m/s for onion bulb conservation. Nevertheless, further enhancements are warranted for effective humidity control.
{"title":"Practical Exploration of the 'Open or Close' Concept: Evaluation of the Hygrothermal Performance of a Bioclimatic Innovation for Onion Bulb Preservation","authors":"B. Ouédraogo, B. Kaboré, G. Ouedraogo, Kalifa Palm, D. Bahiebo","doi":"10.4028/p-ujlek4","DOIUrl":"https://doi.org/10.4028/p-ujlek4","url":null,"abstract":"Substantial losses occur during the storage of onion bulbs due to the inadequacy of available preservation technologies. In an endeavor to contribute to a solution, we evaluate the thermal efficacy of a bioclimatic innovation known as the \"solar cell\" for onion bulb preservation. This assessment involves recording temperature data from both external and internal walls, as well as indoor and outdoor air temperatures, solar irradiation, and relative humidity levels indoors. These measurements offer insights into crucial performance parameters such as thermal phase shift, thermal inertia, thermal decoupling between internal and external environments, relative humidity, damping factor, and thermal amplitude. Furthermore, we examine the impact of external factors, including external temperature and solar radiation. Across different facades, the thermal phase shift of the chamber's structure averages between 5.5 and 10.87 hours. Notably, the maximum thermal phase shift is observed to be 11.67 hours on the Eastern wall. The lowest recorded thermal damping factor is 0.081 on the Western wall, while the highest is 0.337 on the Northern wall. The study of thermal decoupling between the internal and external environments reveals a potential temperature differential of 13.7°C and 9.5°C during the day, and-6°C at night, contingent on the time of year. Consequently, the \"close or open\" operational mode proves to be of significant interest. Exposed to solar radiation peaking at 1041 W/m2, the temperatures of the external facades of the walls experience a substantial increase, reaching up to 52.3°C. Meanwhile, the internal environment maintains a thermal range of 24.21°C to 31.68°C under a maximum airflow of 0.18 m/s. The average relative humidity within the storage chamber fluctuates between 42.65% and 87%. Hence, the solar cell demonstrates its capacity to create optimal conditions of 25°C-30°C and 0.062 m/s for onion bulb conservation. Nevertheless, further enhancements are warranted for effective humidity control.","PeriodicalId":7184,"journal":{"name":"Advanced Engineering Forum","volume":"55 41","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141804985","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}
Jacques Ndikumana, J. R. Kashinga, G. S. Kumaran, Enzoh Langi
The increase in copper productivity in Zambia has resulted in the expansion of disposal areas occupied by mineral wastes and tailings. This not only consumes land but also, due to insufficient management, poses negative environmental impacts and health risks to people. Therefore, efficient and sustainable approaches for the proper management of these waste materials must be developed. In this study, the potential utilization of copper mine tailings was assessed. After analyzing the physical and chemical properties of copper mine tailings from Kitwe Tailings Dam (TD25), hollow concrete block specimens were prepared. Copper mine tailings were used as a partial replacement for cement in the mix design, with replacement ratios as follows: 0% for CBCMT O% (control specimen), 10% for CBCMT1O%, 20% for CBCMT2O%, 30% for CBCMT3O%, 40% for CBCMT4O%, and 50% for CBCMT5O%, all aimed at achieving a target strength of 5 MPa. Specimen compressive strength was evaluated, and it was found that CBCMT1O% and CBCMT2O% achieved the target compressive strength at 28 days of age. Water absorption rates and resistance to acid attack were also assessed. Findings revealed that all specimens outperformed the control specimen in terms of these properties. Furthermore, the environmental feasibility of the hollow concrete blocks specimens was examined, and the results showed limited leaching of heavy metals from the specimens, with concentrations within permissible thresholds. Additionally, a statistical analysis was conducted to study the influence cell shape has on the specimens’ compressive strength. Aimed at identifying the optimal specimen type for achieving compressive strength at an early age, results indicated that cell shape had a significant impact on the 28-day age of hollow concrete blocks. The study proposes a novel copper mine tailings (waste) management approach, by utilizing the potential it has to replace cement in the production of hollow concrete blocks, evident from the observed enhancement of the mechanical and durability properties.
{"title":"An Investigation of the Mechanical and Durability Properties of Hollow Concrete Blocks Made with Copper Mine Tailings as a Partial Cement Replacement","authors":"Jacques Ndikumana, J. R. Kashinga, G. S. Kumaran, Enzoh Langi","doi":"10.4028/p-wc6eo6","DOIUrl":"https://doi.org/10.4028/p-wc6eo6","url":null,"abstract":"The increase in copper productivity in Zambia has resulted in the expansion of disposal areas occupied by mineral wastes and tailings. This not only consumes land but also, due to insufficient management, poses negative environmental impacts and health risks to people. Therefore, efficient and sustainable approaches for the proper management of these waste materials must be developed. In this study, the potential utilization of copper mine tailings was assessed. After analyzing the physical and chemical properties of copper mine tailings from Kitwe Tailings Dam (TD25), hollow concrete block specimens were prepared. Copper mine tailings were used as a partial replacement for cement in the mix design, with replacement ratios as follows: 0% for CBCMT O% (control specimen), 10% for CBCMT1O%, 20% for CBCMT2O%, 30% for CBCMT3O%, 40% for CBCMT4O%, and 50% for CBCMT5O%, all aimed at achieving a target strength of 5 MPa. Specimen compressive strength was evaluated, and it was found that CBCMT1O% and CBCMT2O% achieved the target compressive strength at 28 days of age. Water absorption rates and resistance to acid attack were also assessed. Findings revealed that all specimens outperformed the control specimen in terms of these properties. Furthermore, the environmental feasibility of the hollow concrete blocks specimens was examined, and the results showed limited leaching of heavy metals from the specimens, with concentrations within permissible thresholds. Additionally, a statistical analysis was conducted to study the influence cell shape has on the specimens’ compressive strength. Aimed at identifying the optimal specimen type for achieving compressive strength at an early age, results indicated that cell shape had a significant impact on the 28-day age of hollow concrete blocks. The study proposes a novel copper mine tailings (waste) management approach, by utilizing the potential it has to replace cement in the production of hollow concrete blocks, evident from the observed enhancement of the mechanical and durability properties.","PeriodicalId":7184,"journal":{"name":"Advanced Engineering Forum","volume":"29 4","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141804472","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}
To study the influence of cement-sand ratio, fly ash content, steel slag content, and fiber content on the performance of iron tailings premixed dry mixed mortar based on Box-Behnken, the regression model of compressive strength and fiexural strength and the above four factors was established, and the optimized mix ratio parameters were obtained. The results showed that the significance of the effect on compressive strength is ranked as follows: cement-sand ratio is greater than fly ash content than steel slag powder content than fiber content, and the significance of the effect on flexural strength is ranked as follows: cement-sand ratio is greater than fiber content than steel slag powder content than fly ash content.
{"title":"Optimum Design of Mix Ratio of Premixed Iron Tailings Mortar Based on Response Surface Method","authors":"Huang Yong, Chang Zhi Su, Sun Jian","doi":"10.4028/p-xfk3i4","DOIUrl":"https://doi.org/10.4028/p-xfk3i4","url":null,"abstract":"To study the influence of cement-sand ratio, fly ash content, steel slag content, and fiber content on the performance of iron tailings premixed dry mixed mortar based on Box-Behnken, the regression model of compressive strength and fiexural strength and the above four factors was established, and the optimized mix ratio parameters were obtained. The results showed that the significance of the effect on compressive strength is ranked as follows: cement-sand ratio is greater than fly ash content than steel slag powder content than fiber content, and the significance of the effect on flexural strength is ranked as follows: cement-sand ratio is greater than fiber content than steel slag powder content than fly ash content.","PeriodicalId":7184,"journal":{"name":"Advanced Engineering Forum","volume":"78 4","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141802731","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}
Earth retaining wall structures are common civil engineering structures. Estimation of magnitude and distribution of earth pressure on retaining structures under different surcharge loading conditions is essential as they influence the design and overall economy of retaining structures. Numerical modeling using finite element code PLAXIS is used static analysis. 7 m height of non-yielding cantilever retaining wall with and without EPS geofoam structure is studied and 20 m backfill width was considered. In the present study backfill was modeled as Mohr-Coulomb yield criteria and EPS geofoam and wall were modeled as Linear-elastic. EPS geofoam densities namely 12 kg/m3 and 15 kg/m3 and two different geofoam thicknesses 0.107H and 0.143H were used for static analysis. Three different surcharge loading namely 10 kPa,30kPa and 50kPa which were kept at a distance of 2.0 m away from the wall face. In the static analysis earth pressure distribution for wall with and without geofoam were analyzed. Approximately 50% isolation efficiency was reported. At lower surcharge loads the effectiveness of EPS is more as compare to higher surcharge load and with increase in surcharge load, isolation efficiency gradually decreases and isolation efficiency decreases with increase in buffer modulus. Apart from these serviceability criteria was also checked. Serviceability criteria comprise of lateral deformation of EPS geofoam at sand-geofoam interface and backfill surface settlement were studied. Lower EPS geofoam density and higher EPS geofoam thickness reduces higher magnitude of earth pressure but in this combination the backfill surface settlement was coming very high.
{"title":"Numerical Modeling of Cantilever Retaining Wall Using EPS Geofoam","authors":"Rashid Mustafa","doi":"10.4028/p-wvjmo3","DOIUrl":"https://doi.org/10.4028/p-wvjmo3","url":null,"abstract":"Earth retaining wall structures are common civil engineering structures. Estimation of magnitude and distribution of earth pressure on retaining structures under different surcharge loading conditions is essential as they influence the design and overall economy of retaining structures. Numerical modeling using finite element code PLAXIS is used static analysis. 7 m height of non-yielding cantilever retaining wall with and without EPS geofoam structure is studied and 20 m backfill width was considered. In the present study backfill was modeled as Mohr-Coulomb yield criteria and EPS geofoam and wall were modeled as Linear-elastic. EPS geofoam densities namely 12 kg/m3 and 15 kg/m3 and two different geofoam thicknesses 0.107H and 0.143H were used for static analysis. Three different surcharge loading namely 10 kPa,30kPa and 50kPa which were kept at a distance of 2.0 m away from the wall face. In the static analysis earth pressure distribution for wall with and without geofoam were analyzed. Approximately 50% isolation efficiency was reported. At lower surcharge loads the effectiveness of EPS is more as compare to higher surcharge load and with increase in surcharge load, isolation efficiency gradually decreases and isolation efficiency decreases with increase in buffer modulus. Apart from these serviceability criteria was also checked. Serviceability criteria comprise of lateral deformation of EPS geofoam at sand-geofoam interface and backfill surface settlement were studied. Lower EPS geofoam density and higher EPS geofoam thickness reduces higher magnitude of earth pressure but in this combination the backfill surface settlement was coming very high.","PeriodicalId":7184,"journal":{"name":"Advanced Engineering Forum","volume":"49 22","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141803643","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}
Vetrivel Kumar Kandasamy, Ratchagaraja Dhairiyasamy, S. Rajendran
This investigation presents an experimental study on the performance, specific fuel consumption, and exhaust emissions of a 14-kW diesel engine generator fueled with neat cottonseed biodiesel and biodiesel/diesel blends. Cotton biodiesel was chosen due to its importance as an agricultural crop and potential as a biodiesel feedstock. The fuels tested were (B100 - pure cotton biodiesel), (B7 - 7% biodiesel, 93% Petro diesel), (B20 - 20% biodiesel), (B30 -30% biodiesel), (B50 - 50% biodiesel), and (B70 - 70% biodiesel). The generator was tested at various loads from 0-14 kW. Properties like viscosity, density, and calorific value were measured for each fuel. The results showed that brake thermal efficiency increased with load for all fuels but was lower for higher biodiesel blends. Exhaust gas temperature followed a similar trend. Specific fuel consumption increased with biodiesel content, attributed to the lower energy density of Biodiesel. B100 had the highest NOx emissions but the lowest carbon monoxide and smoke emissions. The study concludes that cottonseed biodiesel and blends can replace Petro diesel in diesel generators. Increasing biodiesel content causes slight reductions in performance but improvements in emissions. The results provide insights into using cotton biodiesel in engines and generators.
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