Pub Date : 2024-07-09DOI: 10.4038/jnsfsr.v52i2.11495
S. N. Malkanthi, K.G.K. Sathsara, P. D. Dharmaratne, H. Galabada
The use of the earth as a building material has been practiced since the beginning of human civilization. Unburnt bricks, rammed earth, adobe, and burnt bricks are some of them. As a result of technological development, adobe has developed into a compressed stabilized earth block (CSEB). The clay percentage of the soil significantly affects the strength of the CSEB. This study focused on controlling the clay percentage by adding larger particles externally using building construction waste and reinforcing them with coconut coir. Different coir amounts by weight from 0.1% to 0.5% with different lengths of 2 cm, 4 cm, 6 cm, and 8 cm were considered for block production. For dry compressive strength and wet compressive strength, the combination of 0.3% coir amount with 6 cm coir length gave the maximum strength, and it also satisfied the required water absorption limit as per the Grade 1 category of the SLS 1382, part 1. After that, using the above combination, the industrial scale (350 × 100 ×175) mm size block was prepared, and its strength also satisfied the SLS 1382 Grade 1 requirements. According to the study, the manufacturing cost for the CSEB is lower than that of cement blocks and clay bricks. The cost for a 1 m2 wall panel preparation using CSEB is 41.52% lower than preparing using burnt clay brick and 8.56% lower than preparing using cement blocks. Therefore, the CSEB can be used as a load-bearing walling material at a low cost and with eco-friendliness.
{"title":"Proposed mix design improvements of compressed stabilized earth blocks (CSEB) with particle packing optimization and coir reinforcement","authors":"S. N. Malkanthi, K.G.K. Sathsara, P. D. Dharmaratne, H. Galabada","doi":"10.4038/jnsfsr.v52i2.11495","DOIUrl":"https://doi.org/10.4038/jnsfsr.v52i2.11495","url":null,"abstract":"The use of the earth as a building material has been practiced since the beginning of human civilization. Unburnt bricks, rammed earth, adobe, and burnt bricks are some of them. As a result of technological development, adobe has developed into a compressed stabilized earth block (CSEB). The clay percentage of the soil significantly affects the strength of the CSEB. This study focused on controlling the clay percentage by adding larger particles externally using building construction waste and reinforcing them with coconut coir. Different coir amounts by weight from 0.1% to 0.5% with different lengths of 2 cm, 4 cm, 6 cm, and 8 cm were considered for block production. For dry compressive strength and wet compressive strength, the combination of 0.3% coir amount with 6 cm coir length gave the maximum strength, and it also satisfied the required water absorption limit as per the Grade 1 category of the SLS 1382, part 1. After that, using the above combination, the industrial scale (350 × 100 ×175) mm size block was prepared, and its strength also satisfied the SLS 1382 Grade 1 requirements. According to the study, the manufacturing cost for the CSEB is lower than that of cement blocks and clay bricks. The cost for a 1 m2 wall panel preparation using CSEB is 41.52% lower than preparing using burnt clay brick and 8.56% lower than preparing using cement blocks. Therefore, the CSEB can be used as a load-bearing walling material at a low cost and with eco-friendliness. ","PeriodicalId":17429,"journal":{"name":"Journal of the National Science Foundation of Sri Lanka","volume":null,"pages":null},"PeriodicalIF":0.4,"publicationDate":"2024-07-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141663117","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"综合性期刊","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-07-09DOI: 10.4038/jnsfsr.v52i2.11765
G. Kanagasundaram, A. Dassanayake, C. Jayawardena, S. Chaminda
This study investigated the relationship between Uniaxial Compressive Strength (UCS) and slake durability index (SDI) in gneiss rocks collected from two aggregate quarry sites. The analysis revealed varying correlations between these two parameters depending on the grouping and categorisation of the data. Initially, a moderate correlation was observed between experimental and estimated UCS values when considering all the data together. However, further examination of the data by dividing it into two categories based on UCS values greater than or equal to 40 MPa and less than 40 MPa yielded insightful results. Within these divided categories, a robust correlation was found between experimental and estimated UCS values for cycles two and four of SDI. Moreover, this study reveals that fresh rock samples from the quarry locations maintained a durability of over 98% through four cycles of the slake durability test. Nonetheless, these same samples exhibited decreased strength, which can be attributed to their mineral composition and internal structural arrangements of the rock samples tested. Therefore, this study incorporated complementary testing methods such as Ultrasonic Pulse Wave Velocity (UPV) and Scanning Electron Microscope/Energy Dispersive X-ray Spectroscopy (SEM/EDX). These tests served as valuable tools for validating the results and enhancing the understanding of micro-scale changes within the gneiss rock samples. The comparison of test values and the exploration of underlying factors confirmed the reliability and usefulness of UPV and SEM/EDX as supporting tools for this study. The study also recommended that the developed equations can be useful for engineers and researchers in estimating rock strength quickly and inexpensively by replacing the laborious tasks involved in traditional laboratory testing.
{"title":"Quantifying the relationship between uniaxial compressive strength and slake durability index in gneiss rocks: an experimental approach","authors":"G. Kanagasundaram, A. Dassanayake, C. Jayawardena, S. Chaminda","doi":"10.4038/jnsfsr.v52i2.11765","DOIUrl":"https://doi.org/10.4038/jnsfsr.v52i2.11765","url":null,"abstract":"This study investigated the relationship between Uniaxial Compressive Strength (UCS) and slake durability index (SDI) in gneiss rocks collected from two aggregate quarry sites. The analysis revealed varying correlations between these two parameters depending on the grouping and categorisation of the data. Initially, a moderate correlation was observed between experimental and estimated UCS values when considering all the data together. However, further examination of the data by dividing it into two categories based on UCS values greater than or equal to 40 MPa and less than 40 MPa yielded insightful results. Within these divided categories, a robust correlation was found between experimental and estimated UCS values for cycles two and four of SDI. Moreover, this study reveals that fresh rock samples from the quarry locations maintained a durability of over 98% through four cycles of the slake durability test. Nonetheless, these same samples exhibited decreased strength, which can be attributed to their mineral composition and internal structural arrangements of the rock samples tested. Therefore, this study incorporated complementary testing methods such as Ultrasonic Pulse Wave Velocity (UPV) and Scanning Electron Microscope/Energy Dispersive X-ray Spectroscopy (SEM/EDX). These tests served as valuable tools for validating the results and enhancing the understanding of micro-scale changes within the gneiss rock samples. The comparison of test values and the exploration of underlying factors confirmed the reliability and usefulness of UPV and SEM/EDX as supporting tools for this study. The study also recommended that the developed equations can be useful for engineers and researchers in estimating rock strength quickly and inexpensively by replacing the laborious tasks involved in traditional laboratory testing.","PeriodicalId":17429,"journal":{"name":"Journal of the National Science Foundation of Sri Lanka","volume":null,"pages":null},"PeriodicalIF":0.4,"publicationDate":"2024-07-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141663395","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"综合性期刊","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-07-09DOI: 10.4038/jnsfsr.v52i2.12276
A. Abeysekera
Many of the important issues that confront society today such as mitigating climate change, alternative energy sources, genetically modified organisms and the use of pesticides and weedicides in agriculture, require the general public to possess scientific literacy to understand and decide amongst different proposals presented by policy makers and politicians. However, it is clear that in today’s world, scientific literacy which is limited only to a knowledge of some basic theories and facts regarding the natural world does not enable society to take reasonable decisions on these issues. This is mainly due to the fact that the controls that existed in the flow of scientific information, such as boards of scientific and academic organizations, editors and knowledgeable science journalists are now being by-passed via social media and the internet. Various ideological and political campaigns are now behind much of what passes as “science”. Fidelity to the truth is no longer a concern. The anti-vaccine drive in many technologically advanced countries during the Covid-19 pandemic, and the banning of chemical fertilizers in Sri Lanka in 2021 stand as illustrative examples. An unfortunate by-product of the digital revolution has been the current age of misinformation. While the implications of these developments for democracy and freedom of expression are being debated, it is evident that being a scientifically literate person implies the ability to evaluate the trustworthiness of science-related information that is so readily available on the internet. The different fields of science are so highly specialized today, that it may not be possible even for a scientist to evaluate the evidence for a particular claim outside one’s own specialty with certainty. Thus, the starting point for both scientists and the general public has to be to assess the trustworthiness of their sources of information. This may not be as straightforward as it seems, but the kinds of questions that should be looked into are conflict of interest, ideological bias, credentials for expertise and level of agreement with other experts in the field. Being able to evaluate ‘who’ is making a claim becomes as important as considering ‘what’ is being claimed.
{"title":"Scientific literacy in the age of misinformation","authors":"A. Abeysekera","doi":"10.4038/jnsfsr.v52i2.12276","DOIUrl":"https://doi.org/10.4038/jnsfsr.v52i2.12276","url":null,"abstract":"Many of the important issues that confront society today such as mitigating climate change, alternative energy sources, genetically modified organisms and the use of pesticides and weedicides in agriculture, require the general public to possess scientific literacy to understand and decide amongst different proposals presented by policy makers and politicians. However, it is clear that in today’s world, scientific literacy which is limited only to a knowledge of some basic theories and facts regarding the natural world does not enable society to take reasonable decisions on these issues.\u0000This is mainly due to the fact that the controls that existed in the flow of scientific information, such as boards of scientific and academic organizations, editors and knowledgeable science journalists are now being by-passed via social media and the internet. Various ideological and political campaigns are now behind much of what passes as “science”. Fidelity to the truth is no longer a concern. The anti-vaccine drive in many technologically advanced countries during the Covid-19 pandemic, and the banning of chemical fertilizers in Sri Lanka in 2021 stand as illustrative examples. An unfortunate by-product of the digital revolution has been the current age of misinformation. \u0000While the implications of these developments for democracy and freedom of expression are being debated, it is evident that being a scientifically literate person implies the ability to evaluate the trustworthiness of science-related information that is so readily available on the internet. The different fields of science are so highly specialized today, that it may not be possible even for a scientist to evaluate the evidence for a particular claim outside one’s own specialty with certainty. Thus, the starting point for both scientists and the general public has to be to assess the trustworthiness of their sources of information. This may not be as straightforward as it seems, but the kinds of questions that should be looked into are conflict of interest, ideological bias, credentials for expertise and level of agreement with other experts in the field. Being able to evaluate ‘who’ is making a claim becomes as important as considering ‘what’ is being claimed. ","PeriodicalId":17429,"journal":{"name":"Journal of the National Science Foundation of Sri Lanka","volume":null,"pages":null},"PeriodicalIF":0.4,"publicationDate":"2024-07-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141664791","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"综合性期刊","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-07-09DOI: 10.4038/jnsfsr.v52i2.11993
J. Keerthana, K.H.I.K. Hewavitharana, K.B. Wijesekara
Abstract Human bone is a composite material of hydroxyapatite (HA) and collagen. HA (Ca10(PO4)6(OH)2) is a biomaterial with the calcium to phosphorus ratio being similar to the natural bone composition. In this study, composite materials were prepared by using poly(lactic acid) (PLA) as a polymer matrix, maleic anhydride (MAH) as a compatibilizer, and natural HA extracted from cow bone (BHA) as a suitable mechanical support filler with positive surface properties. Composites with varying HA (10-30 wt. %), PLA, and with or without MAH (0.5–8 wt. %) were prepared by a thermal decomposition method at 900 ℃. In comparison to commercial HA (CHA), the effect of the PLA and MAH contribution on morphological, thermal, and mechanical properties of BHA were analyzed by X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, thermogravimetric analysis (TGA), scanning electron microscopy (SEM) and tensile strength measurements. As per the results, the HA30/PLA/4MAH composite with 30 wt. % HA, 66 wt. % PLA and 4 wt. % MAH offer the maximum mean tensile strength of 307.71 MPa. The overall results confirm the contribution of MAH compatibilizer in HA/PLA/MAH composite materials for bone tissue engineering from a mechanical point of view.
摘要 人体骨骼是羟基磷灰石（HA）和胶原蛋白的复合材料。HA（Ca10(PO4)6(OH)2）是一种钙磷比例与天然骨成分相似的生物材料。本研究采用聚乳酸（PLA）作为聚合物基体，马来酸酐（MAH）作为相容剂，从牛骨中提取的天然 HA（BHA）作为具有良好表面特性的合适机械支撑填料，制备了复合材料。通过 900 ℃ 下的热分解法制备了不同 HA（10-30 wt.%）、聚乳酸（PLA）和有或无 MAH（0.5-8 wt.%）的复合材料。通过 X 射线衍射 (XRD)、傅立叶变换红外光谱 (FTIR)、热重分析 (TGA)、扫描电子显微镜 (SEM) 和拉伸强度测量，分析了聚乳酸和 MAH 对 BHA 的形态、热和机械性能的影响。结果表明，含 30 重量百分比 HA、66 重量百分比 PLA 和 4 重量百分比 MAH 的 HA30/PLA/4MAH 复合材料的平均拉伸强度最大，达到 307.71 兆帕。总体结果从力学角度证实了 MAH 相容剂在骨组织工程 HA/PLA/MAH 复合材料中的作用。
{"title":"Synthesis and characterization of biocomposite of bovine bone-based hydroxyapatite poly(lactic acid)-maleic anhydride","authors":"J. Keerthana, K.H.I.K. Hewavitharana, K.B. Wijesekara","doi":"10.4038/jnsfsr.v52i2.11993","DOIUrl":"https://doi.org/10.4038/jnsfsr.v52i2.11993","url":null,"abstract":"Abstract \u0000Human bone is a composite material of hydroxyapatite (HA) and collagen. HA (Ca10(PO4)6(OH)2) is a biomaterial with the calcium to phosphorus ratio being similar to the natural bone composition. In this study, composite materials were prepared by using poly(lactic acid) (PLA) as a polymer matrix, maleic anhydride (MAH) as a compatibilizer, and natural HA extracted from cow bone (BHA) as a suitable mechanical support filler with positive surface properties. Composites with varying HA (10-30 wt. %), PLA, and with or without MAH (0.5–8 wt. %) were prepared by a thermal decomposition method at 900 ℃. In comparison to commercial HA (CHA), the effect of the PLA and MAH contribution on morphological, thermal, and mechanical properties of BHA were analyzed by X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, thermogravimetric analysis (TGA), scanning electron microscopy (SEM) and tensile strength measurements. As per the results, the HA30/PLA/4MAH composite with 30 wt. % HA, 66 wt. % PLA and 4 wt. % MAH offer the maximum mean tensile strength of 307.71 MPa. The overall results confirm the contribution of MAH compatibilizer in HA/PLA/MAH composite materials for bone tissue engineering from a mechanical point of view.","PeriodicalId":17429,"journal":{"name":"Journal of the National Science Foundation of Sri Lanka","volume":null,"pages":null},"PeriodicalIF":0.4,"publicationDate":"2024-07-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141663137","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"综合性期刊","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-07-09DOI: 10.4038/jnsfsr.v52i2.11732
R.G.S.S. Perera, J.H.A. Ruwanmali, T. Thevega, J. Jayasinghe, C. S. Bandara, A. J. Dammika
Non-structural internal and external walls play a crucial role in high-rise buildings. Exterior walls contribute to the building’s aesthetic appearance and create a comfortable indoor environment against thermal and wind effects. Interior walls divide the space and minimize sound distractions while maintaining desired conditions. External walls are particularly important as the presence of combustible materials can pose a significant fire hazard. Hence, it is crucial to use materials with high thermal performance to mitigate risks. Glass is a commonly used material for external walls due to its transparency, affordability, availability, and sustainability. However, glass panels are susceptible to failure when exposed to heat due to their brittleness. Therefore, this study aims to assess the thermal performance of glass panels under fire by analyzing single, laminated, and insulated glass panels using ABAQUS finite element software. Through a parametric study using validated numerical models, the study identifies the optimal configuration for glass panels. The findings indicate that increasing the thickness of a single glass panel by 2 mm resulted in a temperature decrease of approximately 13.5%. Additionally, the impact of shape on thermal performance is studied by evaluating crack initiation time and temperature for various shapes with equal areas. The results show that rectangular panels exhibit the poorest thermal performance. Furthermore, the type of glass panel significantly influences thermal performance compared to shape and thickness. Insulated glass panels demonstrate superior performance compared to single and laminated glass panels. When investigating different insulation materials, krypton outperforms argon and air in terms of thermal performance. This study contributes to the advancement of fire-safety solutions in buildings by using a validated numerical model to identify critical parameters affecting the thermal performance of glass facades across various types and configurations.
{"title":"Thermal performance of glass facade under fire loading: a numerical approach","authors":"R.G.S.S. Perera, J.H.A. Ruwanmali, T. Thevega, J. Jayasinghe, C. S. Bandara, A. J. Dammika","doi":"10.4038/jnsfsr.v52i2.11732","DOIUrl":"https://doi.org/10.4038/jnsfsr.v52i2.11732","url":null,"abstract":"Non-structural internal and external walls play a crucial role in high-rise buildings. Exterior walls contribute to the building’s aesthetic appearance and create a comfortable indoor environment against thermal and wind effects. Interior walls divide the space and minimize sound distractions while maintaining desired conditions. External walls are particularly important as the presence of combustible materials can pose a significant fire hazard. Hence, it is crucial to use materials with high thermal performance to mitigate risks. Glass is a commonly used material for external walls due to its transparency, affordability, availability, and sustainability. However, glass panels are susceptible to failure when exposed to heat due to their brittleness. Therefore, this study aims to assess the thermal performance of glass panels under fire by analyzing single, laminated, and insulated glass panels using ABAQUS finite element software. Through a parametric study using validated numerical models, the study identifies the optimal configuration for glass panels. The findings indicate that increasing the thickness of a single glass panel by 2 mm resulted in a temperature decrease of approximately 13.5%. Additionally, the impact of shape on thermal performance is studied by evaluating crack initiation time and temperature for various shapes with equal areas. The results show that rectangular panels exhibit the poorest thermal performance. Furthermore, the type of glass panel significantly influences thermal performance compared to shape and thickness. Insulated glass panels demonstrate superior performance compared to single and laminated glass panels. When investigating different insulation materials, krypton outperforms argon and air in terms of thermal performance. This study contributes to the advancement of fire-safety solutions in buildings by using a validated numerical model to identify critical parameters affecting the thermal performance of glass facades across various types and configurations. ","PeriodicalId":17429,"journal":{"name":"Journal of the National Science Foundation of Sri Lanka","volume":null,"pages":null},"PeriodicalIF":0.4,"publicationDate":"2024-07-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141665107","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"综合性期刊","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-07-09DOI: 10.4038/jnsfsr.v52i2.11576
S. Gnanapragasam, W. Daundasekera
Cross-Docking (CD) is a modern distribution strategy in a supply chain. The optimal scheduling of vehicle routing, known as the Vehicle Routing Problem (VRP), is one of the influential factors of the efficiency of a supply chain. In recent years, researchers and business consultants in different organizations have been interested in integrating the VRP with CD (VRPCD). Since VRPCD is a NP-hard problem, heuristic or meta-heuristic methods are always recommended to solve large-scale VRPCD. The Genetic Algorithm (GA) is a population based meta-heuristic algorithm and also, it is based on the principles of genetic and natural selections. The GA is capable of finding near optimal solutions to large-scale optimization problems which are extremely difficult to solve using traditional optimization algorithms. Therefore, in this study, a meta-heuristic approach based on the GA is proposed to solve the vehicle routing problem with moving shipments at the cross-docking facility (VRPCD&MS). The data are extracted from benchmark instances in the literature. The optimum solutions obtained to small-scale instances by the GA are compared with the exact solutions obtained by the Branch and Bound (BB) algorithm, which is a traditional algorithm to solve problems of this nature. The GA and BB algorithms are respectively coded in MATLAB and LINGO. The results reveal that the relative difference between the exact solution and the near–optimal solution is below 5%. Therefore, it can be concluded that the proposed GA is a better alternative method, considering its overall performance, to solve the VRPCD&MS models. Moreover, since the computational time is low, the proposed GA can be used to schedule the vehicles to the routes of VRPCD&MS at the last moment prior to the start of the time horizon.
交叉对接（CD）是供应链中的一种现代配送策略。车辆路由的优化调度，即车辆路由问题（VRP），是供应链效率的影响因素之一。近年来，不同组织的研究人员和商业顾问都对将 VRP 与 CD（VRPCD）相结合产生了浓厚的兴趣。由于 VRPCD 是一个 NP 难问题，因此总是推荐采用启发式或元启发式方法来解决大规模 VRPCD 问题。遗传算法（GA）是一种基于种群的元启发式算法，它也是基于遗传和自然选择的原理。对于传统优化算法极难解决的大规模优化问题，遗传算法能够找到接近最优的解决方案。因此，本研究提出了一种基于遗传算法的元启发式方法，用于解决交叉对接设施中移动货物的车辆路由问题（VRPCD&MS）。数据来自文献中的基准实例。将利用 GA 获得的小规模实例最优解与利用分支与边界（BB）算法获得的精确解进行了比较，后者是解决此类问题的传统算法。GA 算法和 BB 算法分别用 MATLAB 和 LINGO 编码。结果表明，精确解与近优解之间的相对差异低于 5%。因此，考虑到其整体性能，可以认为所提出的 GA 是解决 VRPCD&MS 模型的一种更好的替代方法。此外，由于计算时间较短，建议的 GA 可用于在时间跨度开始前的最后时刻将车辆调度到 VRPCD&MS 的路线上。
{"title":"Meta-heuristic method to schedule vehicle routing with moving shipments at the cross-docking facility","authors":"S. Gnanapragasam, W. Daundasekera","doi":"10.4038/jnsfsr.v52i2.11576","DOIUrl":"https://doi.org/10.4038/jnsfsr.v52i2.11576","url":null,"abstract":"Cross-Docking (CD) is a modern distribution strategy in a supply chain. The optimal scheduling of vehicle routing, known as the Vehicle Routing Problem (VRP), is one of the influential factors of the efficiency of a supply chain. In recent years, researchers and business consultants in different organizations have been interested in integrating the VRP with CD (VRPCD). Since VRPCD is a NP-hard problem, heuristic or meta-heuristic methods are always recommended to solve large-scale VRPCD. The Genetic Algorithm (GA) is a population based meta-heuristic algorithm and also, it is based on the principles of genetic and natural selections. The GA is capable of finding near optimal solutions to large-scale optimization problems which are extremely difficult to solve using traditional optimization algorithms. Therefore, in this study, a meta-heuristic approach based on the GA is proposed to solve the vehicle routing problem with moving shipments at the cross-docking facility (VRPCD&MS). The data are extracted from benchmark instances in the literature. The optimum solutions obtained to small-scale instances by the GA are compared with the exact solutions obtained by the Branch and Bound (BB) algorithm, which is a traditional algorithm to solve problems of this nature. The GA and BB algorithms are respectively coded in MATLAB and LINGO. The results reveal that the relative difference between the exact solution and the near–optimal solution is below 5%. Therefore, it can be concluded that the proposed GA is a better alternative method, considering its overall performance, to solve the VRPCD&MS models. Moreover, since the computational time is low, the proposed GA can be used to schedule the vehicles to the routes of VRPCD&MS at the last moment prior to the start of the time horizon. ","PeriodicalId":17429,"journal":{"name":"Journal of the National Science Foundation of Sri Lanka","volume":null,"pages":null},"PeriodicalIF":0.4,"publicationDate":"2024-07-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141663452","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"综合性期刊","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-07-09DOI: 10.4038/jnsfsr.v52i2.11820
N.D. Abeyaweera, A. Sivaruban, A. Murugananthan, K. P. Amarasinghe
The Russell’s viper (Daboia russelii) is a medically important viper found in South Asia, including Sri Lanka. This study focused on the phylogeny of Russell’s vipers in the geographically segregated coastal peninsula of Jaffna, Sri Lanka. The study aimed to find out whether the specimens collected in Jaffna are different from previously reported forms since such an investigation has not been carried out so far specifically in this area, and to find out whether geographical segregation has had an impact on it. We obtained mtDNA sequences of samples representing six geographical locations in the Jaffna peninsula for the mitochondrial protein-coding genes Cytb(576bp) and ND2(270bp). Our molecular analyses recovered two distinct clades: D. russelii and D. siamensis. The clade of D. russelii comprises two sister lineages, Pakistan and India/Sri Lanka. The uncorrected pairwise Cytb genetic distance between the species range from 5.0 to 14.5 percent. The current study confirms a sister group relationship between the Indian/Sri Lankan lineage and the Pakistani lineage of the Russell’s viper (D. russelii). Additionally, it discloses the presence of an incipient genetic divergence between Russell’s viper populations in Jaffna and South India.
{"title":"Russell’s viper (Daboia russelii) in the Jaffna peninsula, Sri Lanka bears signatures of incipient genetic divergence from the South Indian population","authors":"N.D. Abeyaweera, A. Sivaruban, A. Murugananthan, K. P. Amarasinghe","doi":"10.4038/jnsfsr.v52i2.11820","DOIUrl":"https://doi.org/10.4038/jnsfsr.v52i2.11820","url":null,"abstract":"The Russell’s viper (Daboia russelii) is a medically important viper found in South Asia, including Sri Lanka. This study focused on the phylogeny of Russell’s vipers in the geographically segregated coastal peninsula of Jaffna, Sri Lanka. The study aimed to find out whether the specimens collected in Jaffna are different from previously reported forms since such an investigation has not been carried out so far specifically in this area, and to find out whether geographical segregation has had an impact on it. We obtained mtDNA sequences of samples representing six geographical locations in the Jaffna peninsula for the mitochondrial protein-coding genes Cytb(576bp) and ND2(270bp). Our molecular analyses recovered two distinct clades: D. russelii and D. siamensis. The clade of D. russelii comprises two sister lineages, Pakistan and India/Sri Lanka. The uncorrected pairwise Cytb genetic distance between the species range from 5.0 to 14.5 percent. The current study confirms a sister group relationship between the Indian/Sri Lankan lineage and the Pakistani lineage of the Russell’s viper (D. russelii). Additionally, it discloses the presence of an incipient genetic divergence between Russell’s viper populations in Jaffna and South India.","PeriodicalId":17429,"journal":{"name":"Journal of the National Science Foundation of Sri Lanka","volume":null,"pages":null},"PeriodicalIF":0.4,"publicationDate":"2024-07-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141836021","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"综合性期刊","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-07-09DOI: 10.4038/jnsfsr.v52i2.11656
H. Shyamalee, A. L. Ranawake
The objective of the present study was to find the genetic diversity of eight improved varieties and eighty-four traditional accessions of rice using nine polymorphic simple sequence repeat (SSR) markers. The SSR markers detected 32 alleles ranging from 2 to 5, with an average of 3.55 alleles per locus, indicating a high genetic diversity. The number of effective alleles (ne) ranged from 1.85 (RM208) to 3.84 (RM493), with an average of 2.64 alleles per locus, which reconfirms an existing broad genetic diversity. Nei’s genetic diversity index (Nei, 1973) was very high (0.5955), indicating a high mean expected heterozygosity (HE). RM493 recorded the maximum polymorphism information content (PIC) value (0.8814). The mean PIC value was 0.5955 for the used SSR markers. Out of nine SSR markers, seven scored more than 0.5 PIC values, proving their potential to be used as genetic markers. Shannon’s information index (I) ranged from 0.65 (RM208) to 1.36 (RM493), with a mean value of 1.00. All genetic diversity indicators, na, ne, HE, PIC and I reflect the high genetic differentiation in representative sample of rice genotypes. According to the unweighted pair group method with arithmetic mean dendrogram and Nei’s genetic distance, the ninety-two rice genotypes were classified into seven groups at an ~85 level of similarity with additional sub-clusters within each group. Rice genotypes with significant genetic divergence can be chosen for upcoming breeding programmes by assessing their positions within the dendrogram. In the dendrogram, genotypes sharing the same name were not clustered together, indicating their distinct genetic backgrounds despite them sharing the same name. The traditional rice accessions clustered together in the dendrogram can be further analysed using more polymorphic SSR markers.
{"title":"Genetic diversity analysis of traditional and improved rice genotypes in Sri Lanka","authors":"H. Shyamalee, A. L. Ranawake","doi":"10.4038/jnsfsr.v52i2.11656","DOIUrl":"https://doi.org/10.4038/jnsfsr.v52i2.11656","url":null,"abstract":"The objective of the present study was to find the genetic diversity of eight improved varieties and eighty-four traditional accessions of rice using nine polymorphic simple sequence repeat (SSR) markers. The SSR markers detected 32 alleles ranging from 2 to 5, with an average of 3.55 alleles per locus, indicating a high genetic diversity. The number of effective alleles (ne) ranged from 1.85 (RM208) to 3.84 (RM493), with an average of 2.64 alleles per locus, which reconfirms an existing broad genetic diversity. Nei’s genetic diversity index (Nei, 1973) was very high (0.5955), indicating a high mean expected heterozygosity (HE). RM493 recorded the maximum polymorphism information content (PIC) value (0.8814). The mean PIC value was 0.5955 for the used SSR markers. Out of nine SSR markers, seven scored more than 0.5 PIC values, proving their potential to be used as genetic markers. Shannon’s information index (I) ranged from 0.65 (RM208) to 1.36 (RM493), with a mean value of 1.00. All genetic diversity indicators, na, ne, HE, PIC and I reflect the high genetic differentiation in representative sample of rice genotypes. According to the unweighted pair group method with arithmetic mean dendrogram and Nei’s genetic distance, the ninety-two rice genotypes were classified into seven groups at an ~85 level of similarity with additional sub-clusters within each group. Rice genotypes with significant genetic divergence can be chosen for upcoming breeding programmes by assessing their positions within the dendrogram. In the dendrogram, genotypes sharing the same name were not clustered together, indicating their distinct genetic backgrounds despite them sharing the same name. The traditional rice accessions clustered together in the dendrogram can be further analysed using more polymorphic SSR markers.","PeriodicalId":17429,"journal":{"name":"Journal of the National Science Foundation of Sri Lanka","volume":null,"pages":null},"PeriodicalIF":0.4,"publicationDate":"2024-07-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141663796","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"综合性期刊","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-07-09DOI: 10.4038/jnsfsr.v52i2.11839
P. Ponram, C. Mythili, NC Selvakumar, A. S. J. Kumar
Musculoskeletal issues can lead to severe immobility problems when not identified and addressed early. An ergonomic assessment and gait analysis of a novel knee joint model featuring an innovative active spring-reinforced centrally-rollable knee bypass support system was conducted in this work. The study employed computer simulations using human knee joint models integrated with the proposed knee support system. Gait parameters, joint angles, and muscle activations were assessed to evaluate the system’s effects on knee joint stability, impact forces, and gait mechanics during various activities. The knee support system notably improved knee joint alignment, lessened joint forces, and optimized muscle activation patterns. The knee bypass support system facilitated a natural knee roll during walking and running, ultimately enhancing gait efficiency and reducing joint stress. The study’s findings showcase improved biomechanics, which hold promising implications for injury prevention, rehabilitation, and overall performance enhancement. With the support system, dynamic changes in tendon forces during activity enhanced the knee joint stability and coordination, which will improve performance and injury prevention. Balance of forces during different activities also encompassed the joint stability. The knee support system demonstrates its potential to address musculoskeletal issues by enhancing knee joint stability and optimizing gait mechanics. This innovation could significantly contribute to minimizing immobility concerns and improving individuals’ quality of life.
{"title":"Ergonomic assessment and gait analysis of a knee joint model with an active spring-reinforced centrally-rollable knee bypass support system\u0000 ","authors":"P. Ponram, C. Mythili, NC Selvakumar, A. S. J. Kumar","doi":"10.4038/jnsfsr.v52i2.11839","DOIUrl":"https://doi.org/10.4038/jnsfsr.v52i2.11839","url":null,"abstract":"Musculoskeletal issues can lead to severe immobility problems when not identified and addressed early. An ergonomic assessment and gait analysis of a novel knee joint model featuring an innovative active spring-reinforced centrally-rollable knee bypass support system was conducted in this work. The study employed computer simulations using human knee joint models integrated with the proposed knee support system. Gait parameters, joint angles, and muscle activations were assessed to evaluate the system’s effects on knee joint stability, impact forces, and gait mechanics during various activities. The knee support system notably improved knee joint alignment, lessened joint forces, and optimized muscle activation patterns. The knee bypass support system facilitated a natural knee roll during walking and running, ultimately enhancing gait efficiency and reducing joint stress. The study’s findings showcase improved biomechanics, which hold promising implications for injury prevention, rehabilitation, and overall performance enhancement. With the support system, dynamic changes in tendon forces during activity enhanced the knee joint stability and coordination, which will improve performance and injury prevention. Balance of forces during different activities also encompassed the joint stability. The knee support system demonstrates its potential to address musculoskeletal issues by enhancing knee joint stability and optimizing gait mechanics. This innovation could significantly contribute to minimizing immobility concerns and improving individuals’ quality of life.","PeriodicalId":17429,"journal":{"name":"Journal of the National Science Foundation of Sri Lanka","volume":null,"pages":null},"PeriodicalIF":0.4,"publicationDate":"2024-07-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141665937","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"综合性期刊","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-07-09DOI: 10.4038/jnsfsr.v52i2.11762
J. Edirisinghe, H. Ranjan, H. Herath, U. K. Jayasinghe Mudalige, M. Wijeratne, V. Kuruppu, C. Jayathilake, W. Wijesuriya, K. Somarathna, S. Karunaratne, S. Jayawardana, D. Gunathilaka, D. Balasooriya
Agriculture is heavily climate dependent. Tea cultivation is of no exception. Tea is cultivated in many developing nations around the globe and the climate change impact is to be mostly felt by developing nations in comparison to the developed. In countries such as Sri Lanka, where the major portion of export earning from agriculture comes from the tea industry, the climate change impacts would harm its progress. Hence, understanding how climate has been linked with production would pave the way for development of a country specific policy. To this end, this research attempted to measure the long-run relationship of the climate with the yield per hectare, using monthly data from 2005 to 2019. A panel Autoregressive Distributed Lag model (ARDL) was used to obtain long-run cointegration between minimum and maximum temperatures and the amount of rainfall received. Data on production and input variables were obtained from records kept at 37 large-scale tea estates at monthly intervals. Monthly temperature and rainfall data were obtained from the Meteorological Department of Sri Lanka. Panel cointegration tests indicated that there is a coexisting long-run relationship between climate variables and the tea yield. Maximum temperature had a positive relationship with yield, but minimum temperature shows a long-run negative relationship. Rainfall is positively related. Production inputs show a long-run positive impact. Thus, the possible negative impacts of rising minimum temperature could be overcome if proper management practices are adopted in the long-run.
{"title":"Impact of climate on tea yield: an empirical investigation from Sri Lanka","authors":"J. Edirisinghe, H. Ranjan, H. Herath, U. K. Jayasinghe Mudalige, M. Wijeratne, V. Kuruppu, C. Jayathilake, W. Wijesuriya, K. Somarathna, S. Karunaratne, S. Jayawardana, D. Gunathilaka, D. Balasooriya","doi":"10.4038/jnsfsr.v52i2.11762","DOIUrl":"https://doi.org/10.4038/jnsfsr.v52i2.11762","url":null,"abstract":"Agriculture is heavily climate dependent. Tea cultivation is of no exception. Tea is cultivated in many developing nations around the globe and the climate change impact is to be mostly felt by developing nations in comparison to the developed. In countries such as Sri Lanka, where the major portion of export earning from agriculture comes from the tea industry, the climate change impacts would harm its progress. Hence, understanding how climate has been linked with production would pave the way for development of a country specific policy. To this end, this research attempted to measure the long-run relationship of the climate with the yield per hectare, using monthly data from 2005 to 2019. A panel Autoregressive Distributed Lag model (ARDL) was used to obtain long-run cointegration between minimum and maximum temperatures and the amount of rainfall received. Data on production and input variables were obtained from records kept at 37 large-scale tea estates at monthly intervals. Monthly temperature and rainfall data were obtained from the Meteorological Department of Sri Lanka. Panel cointegration tests indicated that there is a coexisting long-run relationship between climate variables and the tea yield. Maximum temperature had a positive relationship with yield, but minimum temperature shows a long-run negative relationship. Rainfall is positively related. Production inputs show a long-run positive impact. Thus, the possible negative impacts of rising minimum temperature could be overcome if proper management practices are adopted in the long-run.","PeriodicalId":17429,"journal":{"name":"Journal of the National Science Foundation of Sri Lanka","volume":null,"pages":null},"PeriodicalIF":0.4,"publicationDate":"2024-07-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141663807","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"综合性期刊","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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