iPURSE 2023

Permanent URI for this collectionhttps://ir.lib.pdn.ac.lk/handle/20.500.14444/33

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Numerical investigation of wind interference effects on tall buildings
(University of Peradeniya, Sri Lanka, 2023-09-20) Ekanayake, E. M. R.; Herath, H. M. A. I.; Jayasinghe, J. A. S. C.; Dammika, A. J.
As structures grow taller, their response to wind becomes significantly more pronounced. A particularly noteworthy aspect to consider is the phenomenon of the "interfering effect." This effect, integral to wind engineering, materializes when an upstream structure alters the wind loading on a downstream building. The Computational Fluid Dynamics (CFD) simulation proves to be an effective tool in comprehending this phenomenon. Consequently, the principal objective of this study is to use CFD to qualitatively and quantitatively determine how an upstream building's configuration impacts a downstream building. First, the chosen building structure from the literature was modeled using CFD software. The accuracy of the findings was verified by comparing them with wind tunnel test results published for the same building. Within CFD simulations for wind analysis, three primary approaches are commonly employed: RANS, LES, and DNS. While DNS is acknowledged for its higher accuracy, it demands more computational power. On the other hand, RANS yields reasonably accurate results while utilizing fewer computational resources. Given the constraints of available computing facilities, this study employs the RANS approach to simulate turbulent flow. The validated CFD model was then employed to examine the interference effect on a principal square-shaped building resulting from an upstream building with varying shapes, orientations, and heights. This investigation predominantly focuses on assessing the impact of interfering effects by analyzing the base moment, base shear, and pressure fluctuation of the principal building. The CFD numerical simulations were conducted using the Midas NFX software. Noteworthy outcomes from the investigation's analysis of base moment and base shear underscore the imperative of accounting for a safety factor when designing building structures within urban environments to counter the effects of interference, specifically recommending a factor of 1.3 for worst-case scenarios. Furthermore, the study emphasizes the significance of meticulously designing the cladding system's connection to accommodate both compression and tension forces, as elucidated by the pressure fluctuation results. The discoveries presented in this paper will play a pivotal role in ensuring the stability and safety of building structures for wind load, particularly when these structures are developing within densely populated urban environments.
Optimum cycle clusters to create net-zero transport sector within University of Peradeniya (UOP)
(University of Peradeniya, Sri Lanka, 2023-09-20) Kumaragamage, P.R.B.; Dissanayake, R.D.M.S.N.B.; Devinda, T.H.M.S.; Ekanayake, J.B.; Ekanayake, M.P.B.; Godaliyadda, G.M.R.I.; Herath, V.R.
Many green environments are affected by the use of motorized vehicles. Considering the University premises as a case study this research proposed a bicycle sharing system so as to reduce the carbon emission from the vehicles and to facilitate pedestrian commuting. In achieving this, the locations of the bicycle parking stations, and the number of bicycles needed at each parking station needed to be obtained while optimizing the available resources and minimizing the waiting of the users. The methodology for this research involves collecting data using Google Maps, and two GPS trajectory tracking applications. Multiple clustering algorithms were used to analyze GPS data to identify optimal parking stations for the bicycle sharing system. The data was used to develop a computer simulation model which simulates a bicycle sharing system. The model was designed to simulate various scenarios to minimize waiting for users and maximize bicycle utilization. The collected data, simulation results, and probability curves were analyzed using descriptive statistics and data visualization techniques. The research offered recommendations for the optimal number of parking stations and bicycles to be deployed in each parking station, considering the potential scalability of the system. In conclusion, this project showcases the successful integration of data collection, parameters, and analysis to optimize the bicycle sharing system. Through data-driven insights and heuristic guidance, the system achieves an efficient number of bicycle parking stations and bicycle allocation for each parking station, enhancing sustainability and user satisfaction.
Addressing system and geocoding challenges in Sri Lanka: a case study of dengue incidence mapping in Kandy Municipal Council area
(University of Peradeniya, Sri Lanka, 2023-09-20) Wickramasinghe, A.M.L.T.; Jayasinghe, P.P.
The address system is a fundamental unit for development initiatives and service delivery. A systematic address system is essential for effective geocoding in Geographic Information System (GIS) which leads to better decision-making. The current address system of Sri Lanka has created many challenges for geocoding which is the process of converting addresses into geographic coordinate systems. This study discusses the challenges related to the present address system of Sri Lanka through an experimental study conducted through three scenarios. The dataset encompassed a record of 280 reported dengue cases within the administrative area of the Kandy municipal council. As the first scenario, unstructured addresses of dengue cases were plotted using the available tools of the QGIS software package. In the second scenario, the study arranged the available addresses in a logical order and processed the geocoding query using the same software package. In the third scenario, the researcher used focus group discussions to identify the locations of dengue cases. The identification of the correct location using these three scenarios was not feasible in a geocoding process of GIS. This situation was led by the unstructured addressing system of the country. The study proposes that it is necessary to develop a unique code to identify the exact point of an address in Sri Lanka, without relying on traditional address methods. The new addressing system can be facilitated by the available data collected for the Bimsavia land deed system.
Challenges for implementing an integrated environmental management for sustainable development in Attanagalu Oya river basin
(University of Peradeniya, Sri Lanka, 2023-09-20) Kaushalya, G. N.; Bandara, T.W.M.T.W.; Wijeratne, V. P. I. S.
Attanagalu Oya River Basin can be recognized as an area with a number of environmental issues since the distant past. Such as environmental pollution, resource depletion, deforestation, disasters (floods and drought), land use and land cover changes, and geomorphological landform changes. The previous research that has been done regarding this area explained the weakness of the existing management strategies as the main reason for not managing this situation and importance of effective environmental management. The concept of integrated environmental management (IEM) is a new concept that can be used for an effective environmental management and sustainable development. This research is mainly based on secondary data that was obtained from research papers, reports, and institutional documents. To explore key challenges and solutions to establish an IEM framework in Attanagalu oya river basin a literature review was performed. The finding of the study was interpreted using analytical diagrams and flow charts. According to the findings, there are eight key challenges were identified. Such as [1] problems in identifying environmental legislation, [2] communication issues, [3] lack of awareness of cost- effective methods, [4] process disruption, [5] prevailing socio-economic and political climate, [6] challenges associated with population growth, [7] globalized environmental issues, and [8] achieving national sustainable development goals (NSDGs). Further, it investigates the appropriate solutions that were made in order to overcome those identified challenges. Rising the awareness, environmental education, enhancing communication through new technologies, Cost Benefit Analysis (CBA), Environmental Impact Assessment (EIA), conducting new research, increasing community-based responsibilities and solutions, and proper NSDGs achieving techniques were identified as solutions for those challenges. There are many challenges in establishing an IEM framework for this area. But it is possible to propose solutions for these challenges by examining the factors influencing the emergence of these challenges. This theoretical study will help to enhance the understanding of the challenges in implementing the IEM framework for sustainable development in the Attanagalu Oya River Basin Area. It will create a better pathway for sustainable development in the river basin.
Determination of accurate camera tilt and altitude of “DJI mavic 2 enterprise dual” unmanned aerial vehicle for surveying horizontal and vertical surfaces
(University of Peradeniya, Sri Lanka, 2023-09-20) Solokara, S.M.S.D.; Chathuranga, M.; Vandebona, R.
At present, total stations and level instruments are used for collecting data more accurately. And those instruments can be used for different surfaces accurately. Surveyors also use modern technologies like Unmanned Aerial Vehicle (UAV) surveying to collect data. When conducting UAV surveys in areas with considerable terrain variations, it is important to consider the tilt angle of the camera and the altitude of the UAV to get the highest accuracy possible when considering the data set. Before the UAV is flown, Ground Control Points and checkpoints will be established accurately. The UAV will be flown at different camera tilt angles and altitudes on Horizontal and Vertical surfaces. Observed images will be processed by using Pix4Dmapper software. After data collection, images will be adjusted by using Ground Control Points and check the accuracy of images by using Control Points. In this research expected outcome was selecting the suitable camera tilt angle and altitude of the UAV for collecting data accurately on various surfaces. When determining the camera tilt angle and the altitude the required number of Ground Control Points for surveying various terrain surfaces should be determined as well. In this study was found that five Ground Control Points were enough for a 2500m² area. Also, the most suitable tilt angle and altitude for UAV surveying is 60⁰ tilt angle with 40m altitude respectively for surveying a horizontal surface. Likewise, the most suitable tilt angles and altitudes for UAV surveying are 3m distance from the wall with a 10o tilt angle and 6m distance from the wall with a 10⁰ tilt angle respectively for surveying a vertical surface.
Coal ash derived zeolite X for cationic dye removal from textile wastewater
(University of Peradeniya, Sri Lanka, 2023-09-20) Senarathne, R.P.D.D.; Kalpage, C.S.; Manipura, A.; Botheju, K.
Textile wastewater has been identified as a source of environmental pollution mainly due to the presence of synthetic dyes. Adsorption technology is considered a promising solution for treating textile wastewater. In the present study, Zeolite-X was synthesized from fly and bottom ashes generated in a coal-fired boiler. The alkaline fusion method used for the synthesis and processed Zeolite-X was characterized by FTIR, SEM, and XRD. Synthesized zeolite was subsequently employed for the adsorption of Methylene Blue dye from a synthetic dye solution. Adsorption conditions were optimized to obtain maximum dye removal efficiency using Response Surface Methodology combined with Central Composite Design. The influence of the independent variables on the percentage elimination was evaluated, focusing primarily on the solution pH (3-11), temperature (20- 60 °C), adsorbent mass (2.5 -4.5 g/l), and initial dye concentration (10-50 mg/L). Maximum dye removal efficiencies of 93.01% and 98.15% were obtained for fly ash and bottom ash derived zeolite-X respectively at the same optimum condition (pH 9; temperature 50 °C; initial dye concentration 40 ppm; and solid to liquid ratio 4 g per 1L). Adsorption isotherms were developed at the optimum conditions and the data were fitted to Langmuir and Freundlich isotherm models. The potential of the adsorbent for dye removal was further evaluated by kinetic studies. FAZ data fitted the Langmuir model implying a favorable monolayer adsorption, while BAZ data aligned with the Freundlich model indicating that multilayer adsorption is favorable.
Innovation capabilities of creative industries-in case of pottery industries in Kurunegala District
(University of Peradeniya, Sri Lanka, 2023-09-20) Priyantha, H.R.D.A.
The pottery industry is a traditional industry with archaeological values, covering small industries and entrepreneurs, having remarkable contributions to the economy. Previous studies have shown that the pottery industry is considered the creative and cultural industry. Over the last two decades, new technology has aided the pottery industry enabling its possibilities and making pottery items more innovative. According to the Oslo manual (2018), innovation is crucial for survival in a dynamic environment. The Oslo manual is the key international reference for defining and evaluating innovations. According to the Oslo Manual, a business innovation is a new or enhanced product or business process, or a combination of the two, that differs significantly from the firm's previous products or business processes and has been established on the market or brought into use. Therefore, this research aims to explore the innovation capabilities of pottery industries in the Kurunegala district by considering the Oslo manual publication. A qualitative design was adopted to achieve research objectives. The study sample consists of 7 pottery industry people from the Kurunegala district who have heterogeneous characteristics in their industry. The data were gathered through face-to-face interviews using a pre-determined interview guide. The analysis of the data was done using thematically and a purposive sampling method was used. The findings revealed that the pottery industry in Kurunegala increasingly adapts to different types of innovations. The pottery industry in Kurunegala has practiced product innovations, business process innovations, and distribution and logistics innovations. Researchers questioned pottery people on these three types of innovations and all of the pottery owners agreed with this fact. However, business process innovations were highly practiced compared to the other two innovations in the pottery industry. Modernized business processes, modernized facilities, and customer-based production processes are the major types of business process innovations by considering the interviewees’ responses. As a result, in the pottery business, combining the artistic urge with new technologies enhances both the production processes and the overall design.
Analysis and improvement of compressive strength in self-healing concrete by using bacteria
(University of Peradeniya, Sri Lanka, 2023-09-20) Bandara, H.T.L.K.K.R.; Rathnayake, R.M.L.D.; Fernando, U.B.S.
This research focuses on the impact of bacterial activity, specifically the direct addition of Bacillus subtilis, Bacillus megaterium, and their combination, on the compressive strength of self-healing concrete, to address the issue of concrete's inherent micro-cracks, which can lead to structural degradation and the infiltration of harmful substances. This causes steel corrosion, carbonation, chloride ion erosion, and sulfate erosion, resulting in structural deterioration. Previous researchers have introduced urease-producing bacteria and added a calcium source to the concrete mix, resulting in calcite precipitation. This bacterial biomineralization by utilizing Bacillus bacteria can prevent and repair micro-cracks in concrete structures. This study aims to develop sustainable self-healing concrete by controlling micro-cracks using Bacillus bacteria by analyzing the mechanisms of which Bacillus bacteria enhance compressive strength, microstructural changes, CaCO₃ precipitation, and bacterial growth impact. The compressive strength test, SEM analysis, and water absorption test were conducted to investigate the natural ability of Bacillus bacteria to produce CaCO₃ and heal concrete cracks. The results show that Bacillus subtilis concrete exhibits the highest increase in compressive strength at 25%, followed by the combination of bacterial concrete with a 23.4% improvement, and Bacillus megaterium concrete with a 16.2% increase in compressive strength compared to conventional concrete. Additionally, bacterial concrete exhibited low water absorptivity, indicating a high healing capability compared to conventional concrete. In the combination bacterial concrete, SEM analysis indicates that extending the curing duration enhances the healing efficiency. The combination bacterial concrete exhibited slightly lower compressive strength and healing efficiency compared to Bacillus subtilis alone but higher than Bacillus megaterium alone and significant improvements compared to conventional concrete. Therefore, the combination bacterial concrete appears to strike a balance between compressive strength enhancement and healing capabilities. This can be used in high-strength concrete structures to reduce the costs and challenges associated with external intervention in harsh environments.
Enhancing rural industrial development in Sri Lanka through biogas compression and storage system: a sustainable power solution
(University of Peradeniya, Sri Lanka, 2023-09-20) Gowripalan, A.S.
Biogas, an environmentally friendly power source created from organic waste through anaerobic processing, holds enormous potential for meeting the country’s energy needs. However, it’s low energy density, and ineffective storage options hinder biogas utilisation. Low-pressure gas storage tanks are one of the most common ways to store biogas, although they have shortcomings in safety, transportability, and storage capacity. Biogas is compressed by reducing its volume while raising its pressure, which increases its energy density. This paper analyses the compressing of biogas in LPG cylinders to increase energy generation. Moreover, this paper examines the feasibility of using compressed biogas in rural industries. Firstly, Impurities were removed from the biogas before entering the compression system. Carbon dioxide and moisture were removed using a water scrubber, and the biogas was passed through a Hydrogen sulphide separation unit to extract hydrogen sulphide using the catalyst iron oxide. Then, the purified biogas was compressed in liquefied petroleum gas cylinders weighing 12.5 Kg and 5 kg. Biogas samples from different sources of feed materials, such as pure cow dung and a mix of cow dung and poultry excreta from which the biogas was generated, were used at various cylinder pressures to understand the performance efficiency of internal combustion engines. The average time to run a 3 HP engine is around 40 minutes when using a 12.5 Kg LPG cylinder filled with compressed biogas at 10 Bar. Hence, it is evident that machines powered by compressed biogas can be used for rural industrial activities like coconut oil extraction, brooder houses for chickens, and lifting water for drip and sprinkler irrigation systems.The study reveals that compressed biogas is a viable solution for boosting green rural economic development, and further research is essential to determine the ways and means to run automobiles cost-effectively in Sri Lanka.
The surface morphology and variation of removal of heavy metals from urban runoff using biochar-based cement paste adsorbent
(University of Peradeniya, Sri Lanka, 2023-09-20) Wijeyawardana, H.M.P.; Pramanik, B.K.; Gunasekara, C.; Law, D.; Nanayakkara, K.G.N.; Karunarathna, A.K.
Many studies have reported that Cu, Zn, and Pb, are the most common heavy metals found in urban runoff and they have strong mobility and toxicity. Biochar-containing materials are used for the in-situ removal of heavy metals. However, the effect of cement addition to biochar on heavy metal removal has not been studied in the available literature. Additionally, these studies used biochar synthesized under controlled laboratory conditions using muffle furnaces. The biochar used in this study was prepared using a double chamber draft-down pyrolysis reactor with a residence time of 25 ±5 minutes and pyrolysis temperature of 350-450 ⁰C with paddy husk. Ordinary Portland cement and paddy husk biochar were mixed with an initial water/binder ratio of 0.40. The mixture was packed into Polyvinyl Chloride sections of 50 mm x 100 mm size and column removal experiments were carried out to determine Cu, Pb and Zn removal. Through Scanning Electron Microscopy (SEM) images, hydrated cement products were observed covering parts of the biochar surface and inside the pores of the biochar particle. Thus, the surface area of the biochar available for interaction with heavy metals had decreased. However, the addition of cement 1.5% (v/v) into biochar increased removal capacity approximately 2 times for Cu removal, 3 times for Pb removal and Zn removal. This is due to cement having a higher removal potential of heavy metals compared to plain biochar. The effect of the initial pH on the removal efficiencies of heavy metals was significant for plain biochar but, was negligible for the cement-modified biochar. Hence, the results of this research opened a new pathway in biochar modification. However, the effluent pH was above 11 after cement modification. Thus, the effluent needs to be neutralized before discharge into the environment.
Non-linear damping identification for damage prediction of concrete beams
(University of Peradeniya, Sri Lanka, 2023-09-20) Dissanayake, G.B.; Dammika, A.J.; Bandara, C.S.; Jayasinghe, J.A.S.C.; Dissanayake, P.B.R.
Damping behavior has been proven sensitive to even small, visually undetectable damages. It is known that when a concrete structure is undamaged, damping behavior is modelled by constant damping model. When the structure is damaged, the damping behavior is best described by nonlinear damping model. Thus, by identifying the presence of nonlinearity in damping behavior could reveal the presence of damage in structure. Damping behavior is identified by studying the decay envelope of free vibration in Log-Amplitude scale. Where, constant damping model should best fit to a straight line and common nonlinear damping models, Coulomb and Quadratic damping models, should resemble to concave and convex lines respectively. This decay curve shape characteristic is used to distinguish the nonlinearity in damping behavior of reinforced concrete beam and predict the existence of damage. The experimental study was conducted using flexural free vibration of simply supported reinforced concrete beam. The beam was 200x150mm in cross section and 2700mm in length. The damping behavior of free vibration of beam was investigated at undamaged state (D0) and after different level of flexural damage by loading in four-point bending configuration. Damage states D1-appearance of first crack, D2-appearance of five cracks, D3-appearance of seven cracks, D4-appearance of thirteen cracks, D5-appearance of fifteen cracks. The acceleration time history obtained from the tests were processed using Fast Fourier Analysis and band pass filtering. Then the oscillation peaks were extracted to obtain the decay envelopes and plotted in Log amplitude scale. Then the results were compared with decay curves of ideal damping models described above. It was observed that the constant damping model describes the undamaged beam (D0 state) very well. The decay envelope comparison after each damage states D1, D2, D3, D4, D5 are resembled to convex line depicting quadratic damping behavior. It is seen that rate of decay has significantly increased after the appearance of first crack (D1 state) indicating the potential of damping in portraying even a small damage. This will lead to the suggestion that the damping behavior of the undamaged RCC beam is resemble to constant damping model, and after damage, the damping behavior become nonlinear and distinguishing nonlinearity in decay envelope could portray the existence if damage. It is also important to note that this method is applicable when a single dominant mode is activated, and modes are well separated. Severity of damage in RCC beam may not be characterized by identifying the nonlinearity.
Lateral performance of thin-walled steel box piers under uniaxial and biaxial bending
(University of Peradeniya, Sri Lanka, 2023-09-20) Pigera, A.C.D.; Jenothan, M.; Jayasinghe, J.A.S.C.; Bandara, C.S.; Dammika, A.J.
Usage of steel structures for bridges and viaducts has been the recent trend in the highway construction industry. Steel has been identified as a construction material with long service life, high recoverability, less energy consumption and therefore more sustainable than concrete. Steel structures such as piers (columns) are preferred over their counterpart concrete piers due to their easy and fast construction and minimal disruption to the construction site. Thin-walled steel piers used in these constructions are subjected to various static as well as dynamic loads such as traffic loads, dead loads and seismic loads depending on the region. When it comes to earthquakes, it is important to analyse the piers laterally in both directions. These piers are vulnerable to local buckling due to their low width to thickness ratios and high slenderness ratios. Therefore, they are manufactured with internal stiffener arrangements to provide more resistance towards buckling failures. The focus of this study is to examine the effects of uniaxial and biaxial bending towards the lateral performance of thin-walled steel box piers numerically. Six specimens were created with different width to thickness ratios, slenderness ratios and stiffeners, uniaxial and biaxial cyclic loads were applied on top of the piers and resultant envelope curves were obtained. Results revealed that the models are more vulnerable to overall bucking under biaxial loading conditions. So, this study emphasizes the importance of analysing thin- walled piers under bidirectional loading pattern over the unidirectional loading pattern for structural designs.
Comparative assessment of methodologies for quantifying lateral distortional buckling capacity in steel-concrete composite beams
(University of Peradeniya, Sri Lanka, 2023-09-20) Wijethunge, W. M. A. D.; Dammika, A. J.; Bandara, C. S.; Jayasinghe, J. A. S. C.
Steel-Concrete Composite Beams (SCCBs) employed within interior supports undergo negative moments, leading to compression on the bottom flange and a portion of the steel web. If the web of the steel profile lacks sufficient stiffness to resist lateral bending, it will deform, allowing the compressed flange to displace laterally and twist. This buckling mode is referred to as Lateral Distortional Buckling (LDB). Numerous publications have attempted to explain the behavior of LDB in SCCBs, which can be categorized into two research streams. The first stream focuses on exploring the elastic behavior of LDB by employing bifurcation equilibrium analyses to determine the critical moment at which elastic instability occurs. The second stream investigates the LDB strength of SCCBs through experimental studies or non-linear numerical analyses. However, there are discrepancies in the formulas presented in the literature for calculating the elastic critical moment and different approaches used to estimate LDB strength, deviating from standard procedures. These variations highlight the fact that LDB is still not fully understood by the structural engineering research and design community. Therefore, the main aim of this study is to examine the behavior of SCCBs and compare the theoretical and standard procedures for assessing LDB strength. Finite element (FE) models of SCCBs were developed using ABAQUS software, considering geometric imperfections and material non-linearity. The developed FE models exhibited a strong correlation with experimental results, precisely predicting the ultimate moment capacity of SCCBs with a maximum relative error of less than 2%. Substantial deviations were observed in the elastic critical moment and the ultimate moment when comparing the findings against established approaches. The significance of these insights lies in their ability to guide future research efforts and facilitate comprehensive specification reviews.
Sustainable concrete incorporated with recycled polypropylene plastic waste as coarse aggregate
(University of Peradeniya, Sri Lanka, 2023-09-20) Abirami, T.; Bandara, C.S.; Yapa, H.D.; Dissanayake, P.B.R.
The huge worldwide consumption of concrete and plastic creates environmental problems. For instance, overconsumption of concrete mainly increases CO₂ emissions during cement production and causes natural resource exploitation, energy consumption and harmful pollutants. Furthermore, the majority of plastic waste generated in Sri Lanka is openly dumped in landfills without any precautions. It badly affects the soil, water, human beings and the natural habitat. Hence, using recycled plastic waste as an alternative material for concrete constituents is emerging as an effective sustainable development technique in construction sectors. Even though broad research study has been done in this area all over the world, more experimental verification is essential to implement it in Sri Lanka using available own materials. The current study focuses on small-scale recycling centres where Polypropylene (PP) type plastic waste is mostly recycled. In this study suitability of PP- type recycled plastic waste as a partial replacement for natural coarse aggregate (NCA) in concrete is investigated through experimental work. Priority was given to major concrete properties such as workability and compressive strength. For this purpose, two series of concrete batches were cast with two different types of NCA having maximum nominal sizes of 8mm and 12.5mm. Each series contains one conventional concrete batch and another batch with 20% PP plastic aggregates (PPA) as partial replacement for NCA. Results showed that the compressive strength reduction in PPA concrete batches was almost same regardless of the NCA types used and the reduction percentage is approximately 11%. Further, it was found that the application of PPA concrete in non- structural construction is feasible.
Development of a flood warning system for smart spongy cities
(University of Peradeniya, Sri Lanka, 2023-09-20) Kajeenthan, K.; Herath, K.R.B.
The Sponge City idea has been pushed as a significant work programme to address growing flood danger in metropolitan areas, as well as broader advantages for water resources and urban revitalization. Nevertheless, implementation of the notion necessitates collaboration with a diverse variety of experts as well as impacted populations. Visualization might be beneficial in this process. Flood warning systems may help to mitigate these consequences by assisting in the evacuation of individuals from likely vulnerable regions during peak flash flood periods. As a result, this study presents a conceptual approach to an automated flood warning mobile App. It was examined the issues that sponge city construction faced, as well as potential answers. The flood warning system was developed considering the frequently used permeable pavement materials such as permeable asphalt concrete, permeable cement concrete, permeable brick, and innovative pavement materials. Porous pavement materials were created to satisfy the needs of "infiltration, retention, purification, evaporation, and drainage". Pore properties, such as porosity and pore size. Flow-through the porous medium analysis was done by viewing the media as a continuum using the ABAQUS Darcy's equation model. Finally, these finite element analysis results are integrated to a mobile App which is called ‘’Flood warning APP’’ for faster communication of flood status among road and city users considering the future growth of pavement materials in sponge city to improve the hydrological performances such as infiltration, runoff and absorbance.
A survey of loss functions for SegNet for mosquito breeding site detection
(University of Peradeniya, Sri Lanka, 2023-09-20) Dissanayake, M.B.; Mylvaganam, P.; Niranjan, M.
In recent years, computer vision has witnessed significant advancements, revolutionizing various domains. A critical application we consider, especially in the context of Sri Lanka, is the surveillance of mosquito breeding sites and detection. Efficient and accurate identification of these sites plays a crucial role in effective mosquito vector control programs. SegNet is a deep neural network architecture, successfully applied to many semantic segmentation tasks, making it a compelling choice for mosquito breeding site detection. One of the key parameters which controls the performance of the SegNet is the loss function. Hence, this paper present a comprehensive study on selecting a suitable loss function for SegNet for stagnant water detection application, starting with a systematic empirical comparison of different loss functions. To achieve this objective, first, we created a custom drone image dataset. Using this dataset, we built and trained customized SegNet models using five well-known loss functions, namely Categorical cross-entropy, Binary cross-entropy, Focal Tversky loss, IoU loss, and Dice loss. During the training phase, the model underwent transfer learning-based domain adaptation. I.e. initially, the model was trained on a publicly available large water area dataset, comprising 1,052 RGB images. Thereafter, the model was fine-tuned using locally collected task-specific drone dataset, in the framework of transfer learning. The performance of each 5 cases was compared using Dice Score and Sensitivity, which are popular matrices for segmentation tasks, and the Binary cross-entropy outperformed the others in the test setting. The Dice Score for binary cross-entropy was 0.8334 while the sensitivity was 0.8203. One possible explanation of this is that Binary cross-entropy measures the dissimilarity between the predicted probabilities and the ground truth labels for each pixel independently, and it handles class imbalance well by assigning appropriate importance to each class during the optimization process, effectively preventing dominance by the majority class.
Influence of chrysotile fibers on drying shrinkage of cement paste
(University of Peradeniya, Sri Lanka, 2023-09-20) Deegoda, D.G.I.S.; Buddika, H.A.D.S.; Yapa, H.D.
Different types of fibers are used in building construction to enhance strength and to reduce cracks in structural and non-structural concrete components. Among the fiber cement (FC) composites, FC thin sheets are extensively used as a building material, mainly in ceilings, siding, and flooring. FC thin sheets are lightweight and demonstrate a high strength-to- weight ratio. However, dimensional changes in the sheets and consequent warping are significant issues in these thin FC components. It is noted that drying shrinkage is a notable concern in cement-based materials, particularly in thin components with high surface-to- volume ratios. Hence, it is crucial to investigate the influence of fibers on the drying shrinkage of cement components. This study was conducted to identify the effect of chrysotile fibers on the drying shrinkage of cement paste. The testing mixes comprised chrysotile fibers and ordinary Portland cement (OPC). The chrysotile fibers and OPC were combined in a 1:7 ratio, and water was added to achieve a water/cement of 0.42, mirroring the production of commercial fiber cement thin sheets. Similarly, a control mixture was prepared using the same process without adding chrysotile fibers. Samples were subjected to drying at 25⁰C and relative humidity of 50% and the drying shrinkage of both samples, with and without fiber addition, was observed to be 0.203% and 0.198%, respectively, at the age of 28 days. It was determined that the incorporation of chrysotile fibers did not result in any significant increase or decrease in drying shrinkage. Hence, the influence of chrysotile fibers on drying shrinkage was found to be insignificant. Further investigations could explore alternative approaches to mitigate shrinkage in fiber cement products, such as the incorporation of shrinkage-reducing admixtures.
Photocatalytic activity of sol-gel synthesized Fe₃O₄/MgO nanocomposites for methylene blue dye degradation
(University of Peradeniya, Sri Lanka, 2023-09-20) Gurunanthanan, V.; Wijayaratne, K.B.; Dassanayake, B.S.; Perera, H.C.S.
Water pollution from industrial effluents with organic dyes is an urgent environmental concern. Methylene blue (MB) is particularly problematic due to its wide industrial use and known persistence and toxicity. Photocatalysis offers promise for organic dye degradation, and incorporating magnetic materials allows easy separation and recyclability. We focused on synthesizing Fe₃O₄/MgO nanocomposites and evaluating their photocatalytic activity for MB dye degradation. Fe₃O₄/MgO nanocomposites (particle size = 82.9 nm) were successfully synthesized via a controlled sol-gel method, featuring unique aloe vera stem- like structures with granular particle morphology, indicating a high surface area for enhanced photocatalytic activity. Powder X-ray diffraction confirmed cubic Fe₃O₄ and MgO structures. For photocatalytic degradation, the Fe₃O₄/MgO photocatalyst was dispersed in a 50 ml MB solution and exposed to direct sunlight. Over time, MB concentration progressively decreased, with the characteristic absorption peak vanishing after 2.5 hours. Kinetic analysis yielded an optimum rate constant of 1.55×10−4 s −1 , resulting in 99% degradation after 2.5 hours. Dark adsorption studies established equilibrium with minimal dye concentration variation. In the presence of the catalyst and light, significant degradation occurred, highlighting the catalyst's importance. Control experiments without the catalyst showed no self-degradation of dyes under sunlight (optimum rate constant of 0.95×10−4 s −1 ). The sol-gel-synthesized Fe₃O₄/MgO nanocomposites exhibited excellent photocatalytic efficiency under sunlight, making them promising for organic pollutant treatment in wastewater. Magnetic properties coupled with photocatalytic performance offer an effective and sustainable solution for water pollution from organic dyes. Utilizing these nanocomposites can safeguard the environment and public health from harmful industrial pollution.
Connection between dance and neuroscience: an analysis through the practice of kandyan dance
(University of Peradeniya, Sri Lanka, 2023-09-20) Jayasekara, D.; Mantillake, S.; Senarath, M.K.I.D.
This paper examines the connection between dance and neuroscience based on the experiences of Kandyan dance. Kandyan dance of Sri Lanka has been widely studied as an aesthetic expression and national cultural heritage. Its historical emergence and political role have also been studied. Analyzing Kandyan dance through neuroscience has not been done. This study is a basic attempt to understand the Kandyan dance through the concepts of body and movements in neuroscience. This is a qualitative study. Data comes from our experience as Kandyan dancers, personal reflections, observations, interviews with traditional dancers and bodily experiences. International research reports on brain activity tests, Physical-mental space tests, articles and books were referred to analyze data. Kandyan dance training and the role of the ritualist in dance rituals were analyzed. When grasping the connection between dance and neuroscience three concepts namely, perception, sensation, and emotions were useful. Richard Shusteman’s aesthetics theory of the body was used to understand the neurological reflections of the body on culture and the culture on the body, particularly focusing on Kandyan dance. As a result of this study, a Sinhala language vocabulary and glossary was developed to analyze the connection between dance and neuroscience. Kandyan dance cannot be reduced to a physical activity. It is a connected activity of the body, movement and the culture. Because of their neurological system, Kandyan dancers are aware about the capacities and the limitations of their bodies at any given moment in the dance which they describe as “pattiyan wenawa” in Sinhala. Even when they are not dancing, dancers also feel that they are dancing in their bodies (aenga ethulen natanawa) while they are watching a dance. Concepts of neuroscience helps to explain experiences of Kandyan dancers’ and the finding of this research can help future studies on Kandyan dance and neuroscience.
What is the influence of patient education and compliance on medication for the prevention of diabetic nephropathy?
(University of Peradeniya, Sri Lanka, 2023-09-20) Gunarathna, W.P.P.M.; Rathnayaka, R.M.B.J.K.
Diabetic nephropathy is the leading cause of end-stage renal failure. To control long- term complications of diabetes, hyperglycemia, and hypertension should be controlled. For this patients should have proper knowledge about the disease, relevant tests, and drugs. Non-compliance with medication is the principal cause of complications related to diabetes including kidney failure. Diabetic nephropathy can be prevented with close dietary management, exercise, and the use of appropriate medications. Therefore, knowledge of the disease, tests, medications, and their usage is a critical factor in renal impaired patients. This research was supposed to determine the knowledge level on disease, tests, medications, and usage of such medications of renal impaired patients 100 patients were selected from the diabetic nephropathy clinic, in the General Hospital Kandy. A pre-validated interviewer–administer type questionnaire was given to the selected random sample. It contains 25 questions including open-ended and indirect questions. Marks (1%-100%) were given to each question, final marks were analyzed to decide whether the sample had adequate knowledge and compliance on medication to prevent diabetic nephropathy or not. This research reveals that most of the patients don’t have adequate knowledge about their disease, tests, and drug therapy and a positive physician-patient relationship is the most important factor in improving compliance. Statistical Analysis showed that there exists a linear relationship between compliance and gender/age/education/marital status. To improve patient knowledge and compliance on medication have to increase patient education. Compliance with medication is poor. To alleviate this situation nurses and other health care professionals in clinics and pharmacies have to educate patients about the drugs they are receiving. Pharmacists have a major responsibility to improve patient compliance with medication. Healthcare administrators must recruit enough qualified nurses, pharmacists, and other health care professionals for proper management of patients with diabetic nephropathy.

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