Pub Date : 2021-07-27DOI: 10.1109/MERCon52712.2021.9525651
N. L. Adihetty, Dinuka R Ratnasinghe, Muthuthanthrige L. C. Attygalle, Som Narayan, P. Jha
Three-dimensional (3D) halide perovskites as CH3NH3PbI3 (3D-MAPI) have shown high performance in the perovskite solar cells. However, deep defects due to lattice disorders in the 3D halide perovskite cause to limit the performance of the halide perovskite solar cells. We have numerically simulated and investigated the optimum deep defect density of the 3D-MAPI layer of the p-i-n solar cell model with the structure of Glass/ITO(TCO)/PEDOT: PSS(HTM)/i-2D-MAPI/i-3D-MAPI/i-2D-MAPI/PCBM(ETM)/Ag. Due to the degradation of the organic components under some environmental conditions, the Pb-based organic perovskite solar cells need protective films. This 2D-3D-2D perovskite solar cell has been modeled as a stable perovskite solar cell, by inserting thin 2D-MAPI layers on both sides of the 3D-MAPI to reduce the degradation and moisture issues. Using SCAPS-1D solar cell simulation software, the deep defect density in the 3D halide perovskite layer was optimized to obtain the best performance of the cell model. Our simulation results have indicated that the deep defect density of the 3D-MAPI layer should not exceed 1012cm−3 for high performance. Also, low dark saturation current density and low Shockley-Read-Hall (SRH) recombination current density were observed at the low deep defect density in the 3D-MAPI layer.
{"title":"The Effect of Deep Defects on the Efficiency Variation of CH3NH3PbI3 Perovskite Solar Cells","authors":"N. L. Adihetty, Dinuka R Ratnasinghe, Muthuthanthrige L. C. Attygalle, Som Narayan, P. Jha","doi":"10.1109/MERCon52712.2021.9525651","DOIUrl":"https://doi.org/10.1109/MERCon52712.2021.9525651","url":null,"abstract":"Three-dimensional (3D) halide perovskites as CH3NH3PbI3 (3D-MAPI) have shown high performance in the perovskite solar cells. However, deep defects due to lattice disorders in the 3D halide perovskite cause to limit the performance of the halide perovskite solar cells. We have numerically simulated and investigated the optimum deep defect density of the 3D-MAPI layer of the p-i-n solar cell model with the structure of Glass/ITO(TCO)/PEDOT: PSS(HTM)/i-2D-MAPI/i-3D-MAPI/i-2D-MAPI/PCBM(ETM)/Ag. Due to the degradation of the organic components under some environmental conditions, the Pb-based organic perovskite solar cells need protective films. This 2D-3D-2D perovskite solar cell has been modeled as a stable perovskite solar cell, by inserting thin 2D-MAPI layers on both sides of the 3D-MAPI to reduce the degradation and moisture issues. Using SCAPS-1D solar cell simulation software, the deep defect density in the 3D halide perovskite layer was optimized to obtain the best performance of the cell model. Our simulation results have indicated that the deep defect density of the 3D-MAPI layer should not exceed 1012cm−3 for high performance. Also, low dark saturation current density and low Shockley-Read-Hall (SRH) recombination current density were observed at the low deep defect density in the 3D-MAPI layer.","PeriodicalId":6855,"journal":{"name":"2021 Moratuwa Engineering Research Conference (MERCon)","volume":"34 1","pages":"659-663"},"PeriodicalIF":0.0,"publicationDate":"2021-07-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80351243","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}
Pub Date : 2021-07-27DOI: 10.1109/MERCon52712.2021.9525742
E. Havisanth, S. Kulathilaka
Rainfall induced slopes failures are a very critical issue in Sri Lanka. Natural or cut slopes which remain stable during dry season due to prevalence of high matric suction undergo failure because of loss of matric suction and pore water pressure buildup. Capillary barrier cover system is a cost-effective system with natural soils that could minimize infiltration of rainwater. Capillary barriers are unsaturated cover system that functions in response to change in negative pore water pressure. This research on applicability of capillary barrier cover system on local Sri Lankan cut slopes with 15° slope angle was done through experimental studies and numerical verification of results using GeoStudio, 2012 SEEP/W software.
{"title":"Study on Effectiveness of Capillary Barrier in Reduction of Rainfall Infiltration on a 15° Slope","authors":"E. Havisanth, S. Kulathilaka","doi":"10.1109/MERCon52712.2021.9525742","DOIUrl":"https://doi.org/10.1109/MERCon52712.2021.9525742","url":null,"abstract":"Rainfall induced slopes failures are a very critical issue in Sri Lanka. Natural or cut slopes which remain stable during dry season due to prevalence of high matric suction undergo failure because of loss of matric suction and pore water pressure buildup. Capillary barrier cover system is a cost-effective system with natural soils that could minimize infiltration of rainwater. Capillary barriers are unsaturated cover system that functions in response to change in negative pore water pressure. This research on applicability of capillary barrier cover system on local Sri Lankan cut slopes with 15° slope angle was done through experimental studies and numerical verification of results using GeoStudio, 2012 SEEP/W software.","PeriodicalId":6855,"journal":{"name":"2021 Moratuwa Engineering Research Conference (MERCon)","volume":"24 1","pages":"19-24"},"PeriodicalIF":0.0,"publicationDate":"2021-07-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89862407","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}
Pub Date : 2021-07-27DOI: 10.1109/MERCon52712.2021.9525729
I. Mahakalanda, R. D. S. Arunapriya
Transition from products to services and integrating services into core product offering are well documented in management literature. Here the focus is on the intra-firm operation and supply strategies from a backward integration perspective. The objective of this paper is to develop a smart resource sharing model to facilitate the intra-firm backward integration that enables inhouse manufacturing of selected number of mission critical products. This paper deploys a deterministic mixed integer linear programming model to reshape the current maintenance and repair servicing facility layout to integrate the reverse engineering-based component manufacturing in a naval organization. Analysis of results suggests that this transition involves establishment of a new set of operating policies on resource sharing and job scheduling as the entity relaxes its' service-dominant stance.
{"title":"An MILP-based Intra-firm Smart Resource Sharing Model","authors":"I. Mahakalanda, R. D. S. Arunapriya","doi":"10.1109/MERCon52712.2021.9525729","DOIUrl":"https://doi.org/10.1109/MERCon52712.2021.9525729","url":null,"abstract":"Transition from products to services and integrating services into core product offering are well documented in management literature. Here the focus is on the intra-firm operation and supply strategies from a backward integration perspective. The objective of this paper is to develop a smart resource sharing model to facilitate the intra-firm backward integration that enables inhouse manufacturing of selected number of mission critical products. This paper deploys a deterministic mixed integer linear programming model to reshape the current maintenance and repair servicing facility layout to integrate the reverse engineering-based component manufacturing in a naval organization. Analysis of results suggests that this transition involves establishment of a new set of operating policies on resource sharing and job scheduling as the entity relaxes its' service-dominant stance.","PeriodicalId":6855,"journal":{"name":"2021 Moratuwa Engineering Research Conference (MERCon)","volume":"171 1","pages":"119-123"},"PeriodicalIF":0.0,"publicationDate":"2021-07-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88110768","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}
Pub Date : 2021-07-27DOI: 10.1109/MERCon52712.2021.9525638
Poornima Wanninayake, M. Rathnayake, D. Thushara, S. Gunawardena
Dilute sulfuric acid pretreatment was conducted to extract hemicellulose from rice straw at reduced temperatures (<100 °C), and the process was optimized using experimental design analysis with the response surface methodology. Fourier Transform Infrared Spectroscopy analysis was performed to verify the purity of recovered hemicellulose. Central composite design of experiments (DOE) was applied to develop a statistical model to identify the main effects and interaction effects of process parameters: acid concentration, reaction temperature, and reaction time. The proposed quadratic model showed a high adjusted determination coefficient (0.91) and Fischer's test value (22.4), indicating that the model is adequate to characterize the relationships among the process parameters and explain the variation observed in response. Acid concentration and reaction temperature have significant first order and quadratic effects on hemicellulose recovery. However, reaction time exhibited only a significant quadratic effect on hemicellulose recovery. The maximum hemicellulose yield (15.78%) was obtained at optimal conditions of 0.26 moldm−3 acid concentration, 98.1°C reaction temperature, and 30.48 min reaction time. In addition, residual analysis was carried out to check the adequacy of the proposed model.
{"title":"Optimization of Hemicellulose Recovery from Rice Straw for Biorefinery: Dilute Acid Pretreatment at Reduced Temperatures","authors":"Poornima Wanninayake, M. Rathnayake, D. Thushara, S. Gunawardena","doi":"10.1109/MERCon52712.2021.9525638","DOIUrl":"https://doi.org/10.1109/MERCon52712.2021.9525638","url":null,"abstract":"Dilute sulfuric acid pretreatment was conducted to extract hemicellulose from rice straw at reduced temperatures (<100 °C), and the process was optimized using experimental design analysis with the response surface methodology. Fourier Transform Infrared Spectroscopy analysis was performed to verify the purity of recovered hemicellulose. Central composite design of experiments (DOE) was applied to develop a statistical model to identify the main effects and interaction effects of process parameters: acid concentration, reaction temperature, and reaction time. The proposed quadratic model showed a high adjusted determination coefficient (0.91) and Fischer's test value (22.4), indicating that the model is adequate to characterize the relationships among the process parameters and explain the variation observed in response. Acid concentration and reaction temperature have significant first order and quadratic effects on hemicellulose recovery. However, reaction time exhibited only a significant quadratic effect on hemicellulose recovery. The maximum hemicellulose yield (15.78%) was obtained at optimal conditions of 0.26 moldm−3 acid concentration, 98.1°C reaction temperature, and 30.48 min reaction time. In addition, residual analysis was carried out to check the adequacy of the proposed model.","PeriodicalId":6855,"journal":{"name":"2021 Moratuwa Engineering Research Conference (MERCon)","volume":"57 1","pages":"315-320"},"PeriodicalIF":0.0,"publicationDate":"2021-07-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72674425","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}
Pub Date : 2021-07-27DOI: 10.1109/MERCon52712.2021.9525649
Lwur Dilrukshi, G. De Silva
This work focused on presenting an interpretation for the effect of precipitate size distribution on hardness and strength of the aluminum 6063 extrudates produced in local industry. The same heat treatment process applied in the local industry comprising solution treatment: keeping at 530°C for 4 hours, followed by age hardening treatment: keeping at 205°C for 150 minutes and air cooling, was carried out at laboratory scale. The average hardness and strength of heat-treated samples were measured as 66.5 HV and 210.5 MPa, respectively. Scanning Electron Microscopy - Energy Dispersive X-ray Spectroscopy (SEM/EDS) examination showed that secondary phase precipitates formed during this aging treatment belong to two types of precipitates, they are Silicon-Iron rich and Magnesium-Silicon-Iron rich precipitates. The average number of precipitates, precipitate size and area covered by precipitates were calculated by Image J software. Percentages of precipitates belong to three different size ranges were analyzed as 50.10 percent, 45.13 percent, and 4.77 percent for $0.0-0.2 mu mathrm{m}, 0.2-1.5 mu mathrm{m}$ and above $1.5 mu mathrm{m}$, respectively. The present work can be extended towards the development of a mathematical model to relate the ageing parameters and precipitate size distribution to hardness and strength of Al 6063 extrudates.
本文着重对国内工业生产的6063铝型材的析出相尺寸分布对其硬度和强度的影响进行了解释。在实验室规模上进行了与当地工业相同的热处理工艺，包括固溶处理:在530°C下保持4小时，然后进行时效硬化处理:在205°C下保持150分钟并进行空气冷却。热处理后试样的平均硬度和强度分别为66.5 HV和210.5 MPa。扫描电镜-能量色散x射线能谱(SEM/EDS)分析表明，时效过程中形成的二次相析出物属于富硅铁和富镁硅铁两种析出物。通过Image J软件计算平均析出相数、析出相尺寸和析出相覆盖面积。在$0.0 ~ 0.2 mu mathm {m}$、0.2 ~ 1.5 mu mathm {m}$和$1.5 mu mathm {m}$以上三个不同粒径范围内，析出物的比例分别为50.10%、45.13%和4.77%。目前的工作可以扩展到建立一个数学模型，将时效参数和析出物尺寸分布与Al 6063挤出物的硬度和强度联系起来。
{"title":"An Investigation of the Effect of Precipitate Size Distribution on Mechanical Properties of Aluminum 6063 Extrudates used for Window Frames","authors":"Lwur Dilrukshi, G. De Silva","doi":"10.1109/MERCon52712.2021.9525649","DOIUrl":"https://doi.org/10.1109/MERCon52712.2021.9525649","url":null,"abstract":"This work focused on presenting an interpretation for the effect of precipitate size distribution on hardness and strength of the aluminum 6063 extrudates produced in local industry. The same heat treatment process applied in the local industry comprising solution treatment: keeping at 530°C for 4 hours, followed by age hardening treatment: keeping at 205°C for 150 minutes and air cooling, was carried out at laboratory scale. The average hardness and strength of heat-treated samples were measured as 66.5 HV and 210.5 MPa, respectively. Scanning Electron Microscopy - Energy Dispersive X-ray Spectroscopy (SEM/EDS) examination showed that secondary phase precipitates formed during this aging treatment belong to two types of precipitates, they are Silicon-Iron rich and Magnesium-Silicon-Iron rich precipitates. The average number of precipitates, precipitate size and area covered by precipitates were calculated by Image J software. Percentages of precipitates belong to three different size ranges were analyzed as 50.10 percent, 45.13 percent, and 4.77 percent for $0.0-0.2 mu mathrm{m}, 0.2-1.5 mu mathrm{m}$ and above $1.5 mu mathrm{m}$, respectively. The present work can be extended towards the development of a mathematical model to relate the ageing parameters and precipitate size distribution to hardness and strength of Al 6063 extrudates.","PeriodicalId":6855,"journal":{"name":"2021 Moratuwa Engineering Research Conference (MERCon)","volume":"80 1","pages":"676-680"},"PeriodicalIF":0.0,"publicationDate":"2021-07-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77364486","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}
Pub Date : 2021-07-27DOI: 10.1109/MERCon52712.2021.9525672
M.A.T.C . Perera, Kasun Muthunayaka, D. Madushanka, V. C. Liyanaarachchi, M. Premaratne, T. Ariyadasa
The complicated and varying weather conditions and contamination from fungi, protozoa, and bacteria are major problems associated with outdoor microalgae cultivation. In this study, outdoor microalgae cultivation was investigated in a 3.2 L vertical tubular photobioreactor in Moratuwa, Sri Lanka. During December, when both the solar irradiation and temperature were high, the water spray system in combination with two agro shading nets (each with a shading rate of 40-50%) could effectively reduce the temperature to $2 pm 2 {}^{0}mathrm{C}$ and control solar irradiation below 13500 lux. Under an initial biomass density of 0.2875 g/L and an atmospheric air flow rate of 1 vvm, Haematococcus pluvialis showcased a maximum biomass accumulation of 0.45 g/L and the maximum productivity of 20 mg/L/day. In addition, the reactor system and its design exhibited good performance, implying a potential scale-up opportunity. However, operation under outdoor conditions showed slightly poorer performance due to the light inhibition effect.
{"title":"Investigation of the Effect of Solar Irradiation and Temperature on H. pluvialis Production in Photobioreactors Under Outdoor Cultivation in Sri Lanka","authors":"M.A.T.C . Perera, Kasun Muthunayaka, D. Madushanka, V. C. Liyanaarachchi, M. Premaratne, T. Ariyadasa","doi":"10.1109/MERCon52712.2021.9525672","DOIUrl":"https://doi.org/10.1109/MERCon52712.2021.9525672","url":null,"abstract":"The complicated and varying weather conditions and contamination from fungi, protozoa, and bacteria are major problems associated with outdoor microalgae cultivation. In this study, outdoor microalgae cultivation was investigated in a 3.2 L vertical tubular photobioreactor in Moratuwa, Sri Lanka. During December, when both the solar irradiation and temperature were high, the water spray system in combination with two agro shading nets (each with a shading rate of 40-50%) could effectively reduce the temperature to $2 pm 2 {}^{0}mathrm{C}$ and control solar irradiation below 13500 lux. Under an initial biomass density of 0.2875 g/L and an atmospheric air flow rate of 1 vvm, Haematococcus pluvialis showcased a maximum biomass accumulation of 0.45 g/L and the maximum productivity of 20 mg/L/day. In addition, the reactor system and its design exhibited good performance, implying a potential scale-up opportunity. However, operation under outdoor conditions showed slightly poorer performance due to the light inhibition effect.","PeriodicalId":6855,"journal":{"name":"2021 Moratuwa Engineering Research Conference (MERCon)","volume":"1 1","pages":"327-332"},"PeriodicalIF":0.0,"publicationDate":"2021-07-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90899162","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}
Pub Date : 2021-07-27DOI: 10.1109/MERCon52712.2021.9525774
J. Jayaweera, M. Narayana, S. Adikary
Drying process of green ceramic bodies are complicated due to simultaneous and coupled heat and mass transfers. Dimensional variations and mechanical stresses occur within the ceramic body during drying may create defects in the final product if drying conditions are not carefully controlled. In this study, the drying behavior of Sri Lankan Kaolin was investigated. Initially, Kaolin was characterized using wet chemical analysis and X-ray diffraction to investigate structure and composition. Two batches of Kaolin with different particle size distributions were prepared using wet ball mill grinding with average particles size (D50) of $4.07 mumathrm{m}$ and $3.57 mumathrm{m}$ respectively. Green ceramic samples were obtained using extrusion process. Samples were dried in oven at 60°C and moisture variation of the green product was measured with time. Critical moisture content of the Sri Lankan Kaolin was 1.50%. Mathematical relationship was formulated to determine drying behavior of Sri Lankan Kaolin. An unsteady three-dimensional (3D) model was developed and simulated in Computational Fluid Dynamics (CFD) framework. Simulation results developed by the model were compared with data obtained by experiments conducted using Sri Lankan Kaolin. The model results were validated and comply with experiments results and R2 value was 0.9.
绿色陶瓷体的干燥过程由于传热传质同时发生和耦合而变得复杂。如果干燥条件控制不当，在干燥过程中陶瓷体内发生的尺寸变化和机械应力可能会在最终产品中产生缺陷。本文对斯里兰卡高岭土的干燥特性进行了研究。首先，利用湿化学分析和x射线衍射来研究高岭土的结构和组成。采用湿法球磨法制备了两批不同粒径分布的高岭土，平均粒径(D50)分别为$4.07 mu mathm {m}$和$3.57 mu mathm {m}$。采用挤压法制备了绿色陶瓷样品。样品在60°C的烘箱中干燥，并测量绿色产品的水分随时间的变化。斯里兰卡高岭土的临界含水率为1.50%。建立了确定斯里兰卡高岭土干燥性能的数学关系。在计算流体力学(CFD)框架下建立了非定常三维(3D)模型并进行了仿真。将模型模拟结果与斯里兰卡高岭土试验数据进行了比较。模型结果经过验证，符合实验结果，R2值为0.9。
{"title":"Numerical Modeling of Drying Behavior of Sri Lankan Kaolin","authors":"J. Jayaweera, M. Narayana, S. Adikary","doi":"10.1109/MERCon52712.2021.9525774","DOIUrl":"https://doi.org/10.1109/MERCon52712.2021.9525774","url":null,"abstract":"Drying process of green ceramic bodies are complicated due to simultaneous and coupled heat and mass transfers. Dimensional variations and mechanical stresses occur within the ceramic body during drying may create defects in the final product if drying conditions are not carefully controlled. In this study, the drying behavior of Sri Lankan Kaolin was investigated. Initially, Kaolin was characterized using wet chemical analysis and X-ray diffraction to investigate structure and composition. Two batches of Kaolin with different particle size distributions were prepared using wet ball mill grinding with average particles size (D50) of $4.07 mumathrm{m}$ and $3.57 mumathrm{m}$ respectively. Green ceramic samples were obtained using extrusion process. Samples were dried in oven at 60°C and moisture variation of the green product was measured with time. Critical moisture content of the Sri Lankan Kaolin was 1.50%. Mathematical relationship was formulated to determine drying behavior of Sri Lankan Kaolin. An unsteady three-dimensional (3D) model was developed and simulated in Computational Fluid Dynamics (CFD) framework. Simulation results developed by the model were compared with data obtained by experiments conducted using Sri Lankan Kaolin. The model results were validated and comply with experiments results and R2 value was 0.9.","PeriodicalId":6855,"journal":{"name":"2021 Moratuwa Engineering Research Conference (MERCon)","volume":"60 1","pages":"48-53"},"PeriodicalIF":0.0,"publicationDate":"2021-07-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88763730","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}
Pub Date : 2021-07-27DOI: 10.1109/MERCon52712.2021.9525678
N. Batapola, N. Dushyantha, N. Ratnayake, R. Premasiri, B. Abeysinghe, O. Dissanayake, S. Rohitha, Saman Ilankoon, P. Dharmaratne
In the recent few years, rare earth elements (REEs) were considered as critical metals with strategic importance due to their high usage in modern technology and green energy applications. Currently, with the unexpected increase of rare earth element (REE) demand and China's market dominance, many REE processing projects are being launched or revived. In this regard, the present work is focused on assessing the REE potential in the beach placers along the southwest coastline in Sri Lanka. The collected 36 beach sand samples from the mean sea-level in the southwest coast during both southwestern and northeastern monsoons were subjected to both elemental and mineralogical analyses. Based on the findings, Galle, Ginthota, Wadduwa, and Thelwatta areas were found with significant contents of REEs ranging from 32.8-1,359.1 mg/kg. Moreover, the results suggest that REE-bearing heavy minerals are heavily concentrated in the beach face due to stronger oceanic currents generated by the strong winds of the southwestern monsoon along with the increased sediment supply by inland rivers. The findings in this study would provide insights for future REE prospecting studies, which is helpful in unraveling the hidden potential of REE resources in Sri Lankan beach placer deposits.
{"title":"Rare earth element potential in the beach placers along the southwest coast of Sri Lanka","authors":"N. Batapola, N. Dushyantha, N. Ratnayake, R. Premasiri, B. Abeysinghe, O. Dissanayake, S. Rohitha, Saman Ilankoon, P. Dharmaratne","doi":"10.1109/MERCon52712.2021.9525678","DOIUrl":"https://doi.org/10.1109/MERCon52712.2021.9525678","url":null,"abstract":"In the recent few years, rare earth elements (REEs) were considered as critical metals with strategic importance due to their high usage in modern technology and green energy applications. Currently, with the unexpected increase of rare earth element (REE) demand and China's market dominance, many REE processing projects are being launched or revived. In this regard, the present work is focused on assessing the REE potential in the beach placers along the southwest coastline in Sri Lanka. The collected 36 beach sand samples from the mean sea-level in the southwest coast during both southwestern and northeastern monsoons were subjected to both elemental and mineralogical analyses. Based on the findings, Galle, Ginthota, Wadduwa, and Thelwatta areas were found with significant contents of REEs ranging from 32.8-1,359.1 mg/kg. Moreover, the results suggest that REE-bearing heavy minerals are heavily concentrated in the beach face due to stronger oceanic currents generated by the strong winds of the southwestern monsoon along with the increased sediment supply by inland rivers. The findings in this study would provide insights for future REE prospecting studies, which is helpful in unraveling the hidden potential of REE resources in Sri Lankan beach placer deposits.","PeriodicalId":6855,"journal":{"name":"2021 Moratuwa Engineering Research Conference (MERCon)","volume":"74 1","pages":"415-420"},"PeriodicalIF":0.0,"publicationDate":"2021-07-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81624793","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}
Pub Date : 2021-07-27DOI: 10.1109/MERCon52712.2021.9525676
G. C. S. Jayaweera, H. D. Hidallana-Gamage, W. P. R. Indrajith
Maximum crack width of reinforced concrete (RC) structures should be controlled for satisfying the serviceability and durability requirements of the structures. However, the crack width analysis of RC structures is not much easy because of the complexity of the parameters which affect the crack width. In the Sri Lankan context, there is no specific simplified guidance in terms charts and tables for crack width calculations of circular RC columns. Hence, it is important to develop such guidance. This research deals with the crack width analysis of circular RC columns in straight viaduct sections. A comprehensive study was carried out regarding the behaviour of the cracks in circular RC columns in viaduct sections as per the design standard, BS 5400. Autodesk Structural Bridge Design software was used to perform crack width calculations and MIDAS Civil software was used to do the Finite Element Analysis (FEA) and validation process. The comprehensive design charts developed in this research will be useful in calculating the crack widths in circular RC columns without following any time-consuming methods. Therefore, the findings of this research will be helpful to enhance the efficiency of the design work related to the crack width calculations of circular RC columns.
{"title":"Development of Design Guidance for Circular Reinforced Concrete Columns Incorporating Crack Width","authors":"G. C. S. Jayaweera, H. D. Hidallana-Gamage, W. P. R. Indrajith","doi":"10.1109/MERCon52712.2021.9525676","DOIUrl":"https://doi.org/10.1109/MERCon52712.2021.9525676","url":null,"abstract":"Maximum crack width of reinforced concrete (RC) structures should be controlled for satisfying the serviceability and durability requirements of the structures. However, the crack width analysis of RC structures is not much easy because of the complexity of the parameters which affect the crack width. In the Sri Lankan context, there is no specific simplified guidance in terms charts and tables for crack width calculations of circular RC columns. Hence, it is important to develop such guidance. This research deals with the crack width analysis of circular RC columns in straight viaduct sections. A comprehensive study was carried out regarding the behaviour of the cracks in circular RC columns in viaduct sections as per the design standard, BS 5400. Autodesk Structural Bridge Design software was used to perform crack width calculations and MIDAS Civil software was used to do the Finite Element Analysis (FEA) and validation process. The comprehensive design charts developed in this research will be useful in calculating the crack widths in circular RC columns without following any time-consuming methods. Therefore, the findings of this research will be helpful to enhance the efficiency of the design work related to the crack width calculations of circular RC columns.","PeriodicalId":6855,"journal":{"name":"2021 Moratuwa Engineering Research Conference (MERCon)","volume":"163 1","pages":"148-153"},"PeriodicalIF":0.0,"publicationDate":"2021-07-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86422880","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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