University of Sri Jayewardenepura: Journals & Proceedings
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Epoxy/Graphene Composite for Industrial Applications
No full textAs of now, there is a prominent, global trend to reveal an efficient plus large-scale production method to produce Graphene as of its extraordinary electrical, mechanical and chemical properties of two-dimensional Graphene nanostructure. The main aim of the initial part of the study is to develop an innovative, cost-effective and eco-friendly Graphene production. Liquid phase exfoliation of Graphite via bath sonication in an ethanol/Deionized (DI) water mixture was employed to synthesise the Graphene. Obtained Graphene samples were subjected to miscellaneous analysing techniques to characterize the output. X-Ray Diffraction (XRD) data confirmed that the synthesized sample was graphene. Moreover, the product was within the nano-scale range. The mean crystalline size of the Graphene was determined by the Scherrer’s formula and the calculated value was 80.0 nm. Functional group investigation of the prepared sample was done by Fourier-Transform Infrared Spectroscopy (FTIR) analysis which confirmed that the sample underwent neither oxidation reactions during the preparation process. The degree of defect density of the acquired sample was measured by the Raman analysis. Morphological changes of the graphene were detected through the microscopic surface analysis based on the Scanning Electron Microscope (SEM) images. Though the neat Epoxy resin is widely used in divergent industries, it has several undesirable properties which limit most vital applications. Synthesized Graphene can act as a utilitarian nanofiller to drastically reduce the unfavourable characteristics of the resin and enhance the existing properties of the Epoxy. Therefore, the second section of the research demonstrates a facile, novel and low-cost industrial-scale preparation of Epoxy nanocomposite with the incorporation of synthesized Graphene. Nanocomposite was developed through a vigorous mechanical stirring process and industrial applicability of the composite was estimated based on the electrical conductivity variation and melting point variation of the Epoxy/Graphene composite.
Keywords: Graphene nanostructure, Liquid phase exfoliation, Defect Density, Nanofiller, Nanocomposit
Impact of Silicon Amendments on Insect Pest Infestation and Yield in Parachute Established Rice Seedlings
No full textRice (Oryza sativa L.), the staple food crop in Sri Lanka, faces severe threats from various insect pests, leading to significant yield losses. Use of insecticides is the primary pest control method used by farmers in Sri Lanka. However, insecticides can have adverse effects, including the development of insect resistance, pest resurgence, and chemical residue buildup. For sustainable development, pest management systems must follow ecological principles and should be economically viable. Silicon (Si) has gained attention as an eco-friendly, cost-effective strategy in integrated pest management (IPM) for rice cultivation. Therefore, this study aims to elucidate the potential of Si as a crucial component in environmentally friendly pest management strategies. In this experiment, research plots of 20.25 m2 were established with Bg 94-1 parachute seedlings treated with Si at different rates. The experiment was conducted in a randomized complete block design with 3 replicates over 3 seasons: 2020/21 maha, 2021/22 maha, and 2022 yala, at the Regional Rice Research & Development Centre, Bombuwela. During the 2020/21 maha season, parachute seedlings were treated with 35 g and 25 g of granular SiO2 (Agrisilica), 9 g and 6.5 g of powdered SiO2 (amorphous silica), and a control group without Si amendment to evaluate the impact of Si on the occurrence of major insect pests in rice. Different rates of SiO2 were added to the parachute trays at the time of seeding. Twenty-one-day-old parachute seedlings were established in the research field, and insect pest counts were taken under natural infestation conditions. The results showed no significant differences in the percentage of infested galls or the number of Brown Plant Hoppers (BPH) among treatments. Therefore, the Si application rates were increased to 70 g and 50 g of granular SiO₂ (Agrisilica) and 18 g and 13 g of powdered SiO₂ (amorphous silica) per parachute tray. During the 2021/22 maha season, the numbers of thrips and paddy bugs were significantly lower (p≤0.01) in Si-treated seedlings than in the control. In the 2022 yala season, infested gall percentages and paddy bug counts were also significantly lower (p≤0.01) in Si-treated seedlings compared to the control. Further, there was a significant yield increase (p≤0.01) in Si-treated plots compared to the control. Our results indicate that Si amendment at the rate 50 g of granular SiO2 (Agrisilica) & 13 g of powdered SiO2 (amorphous silica) per tray can provide substantial protection from some of the rice pests under field conditions. These findings support the recommendation of Si amendment as a key component of IPM in rice cultivation.
Keywords: Parachute seedlings, Rice, Silicon amendment
Exploring the Potential of Bacillus subtilis Is1 and B. Amyloliquificiens Is6 to Manage Salinity Stress and Fusarium Wilt Disease in Tomato Plants by Induced Physiological Responses
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The intensified concerns related to agrochemicals’ ecological and health risks have encouraged the exploration of microbial agents as eco-friendly alternatives. Some members of Bacillus spp. are potential plant-growth-promoting agents and benefit numerous crop plants globally. This study aimed to explore the beneficial effects of two Bacillus strains (B. subtilis strain IS1 and B. amyloliquificiens strain IS6) capable of alleviating the growth of tomato plants against salinity stress and Fusarium wilt disease. These strains were able to significantly promote the growth of tomato plants and biomass accumulation in pot trials in the absence of any stress. Under salinity stress conditions (150 mM NaCl), B. subtilis strain IS1 demonstrated superior performance and significantly increased shoot length (45.74%), root length (101.39%), fresh biomass (62.17%), and dry biomass (49.69%) contents compared to control plants. Similarly, B. subtilis strain IS1 (63.7%) and B. amyloliquificiens strain IS6 (32.1%) effectively suppressed Fusarium wilt disease and significantly increased plant growth indices compared to the pathogen control. Furthermore, these strains increased the production of chlorophyll, carotenoid, and total phenolic contents. They significantly affected the activities of enzymes involved in antioxidant machinery and the phenylpropanoid pathway. Hence, this study effectively demonstrates that these Bacillus strains can effectively alleviate the growth of tomato plants under multiple stress conditions and can be used to develop bio-based formulations for use in the fields.
Keywords: Salinity Stress, Fusarium Wilt, Induced Resistance, Bacillus, PGP
A Comparative Assessment of Water Pollution in Beira Lake and Ihalagama Lake in the Western Province of Sri Lanka
No full textUrban Lakes have been subjected to water quality degradation due to various anthropogenic stressors. Beira Lake is a landmark in Colombo City, Sri Lanka, and Ihalagama Lake in Ragama, Sri Lanka, were selected to assess the comparative water pollution in urban lakes. Monthly water samples were collected from September 2023 to February 2024, two sites each at Beira and Ihalagama Lakes, assessing the in-situ (Calibrated multiparameter HACH/ Model) and ex-situ parameters. Data analysis was done using One-way ANOVA followed by Tukey’s pairwise comparison using MINITAB 17.0. The mean Conductivity of Beira Lake (185.76±7.91 µS/cm) was significantly higher than in Ihalagama Lake (152.24±3.60 µS/cm). Mean concentrations of nitrates (1.73 mg/L) and phosphates (1.07 mg/L) were significantly higher in Beira Lake than Ihalagama Lake. Biological Oxygen demand concentrations ranged between 5.23 mg/L and 8.43 mg/L in Beira Lake and from 1.09 mg/L to 3.87 mg/L in Ihalagama Lake. The highest Chemical oxygen demand concentrations reported in Beira Lake were 856.0 mg/L and 469.0 mg/L in Ihalagama Lake. Mean chemical oxygen demand and biological oxygen demand concentrations were significantly greater in Beira Lake where the ambient water quality standards for aquatic life declared by CEA for BOD and COD were as follows 4 mg/L and 15 mg/L. The proposed water pollution index (WPI) contains a scale of 04 categories including excellent (WPI < 0.5), good (WPI = 0.5–0.75), moderately polluted (WPI = 0.75–1) and highly polluted (WPI is >1) based on the standard permissible limits of water quality suitable for aquatic life in Sri Lanka. The WPI of Beira Lake and Ihalagama Lake varied 1.856, and 0.357 respectively. Beira Lake falls into the highly polluted aquatic ecosystem category, while Ihalagama Lake indicates an excellent water quality suitable for aquatic life. The principal component analysis biplot reflects positive correlations between phosphate, nitrate and BOD and nitrate. This study concludes the ecological impacts of deteriorating water quality caused by sewage, municipal wastages and anthropogenic runoff leading to uncontrolled eutrophication. This study proposes continuous monitoring of water quality parameters and regulatory measures to prevent pollutant emissions.
Keywords: Beira lake, Central Environmental Authority, Ihalagama lake, Water pollution inde
Assessing the Growth Performance of Chlorella vulgaris Using Low Cost Growth Media as a Bioenergy Source
No full textIndustrialization has significantly increased the dependence of fossil fuel, which are often regarded as unsustainable due to several challenges: dwindling oil supplies, rising cost and their substantial contribution to environmental degradation through the emission of greenhouse gases. These environmental impacts are critical drivers of climate change, making a transition from non-renewable to renewable energy sources essential for a more sustainable future. Among the promising solutions, bioenergy has gained attention as a key alternative fossil fuel offering potential and environmental and economic benefits. Among various bioenergy sources, microalgae have emerged as one of the most promising feedstocks for biofuel production. Microalgae, Chlorella vulgaris, are fast growing, eukaryotic organisms capable of performing photosynthesis highly efficiently. As cost-effective culturing of microalgae is crucial for the successful production of biofuels, different alternatives need to be investigated. The objective was to comparatively evaluate the growth performance of microalgae species C. vulgaris using recommended betel fertilizer (N-10%: P2O5-10%: K2O-8%) medium with Guillard and Ryther’s modified F/2 media. The experiment was designed using a Randomized Complete Block Design with four replicates for 10 days duration and concentrations of betel fertilizer varied based on N content. These concentrations were similar to F/2 medium, half concentration and double concentration. The 500 ml conical flask was used for cultivation of microalgae with aeration under laboratory conditions. The beetle fertilizer mixture with N content similar to that of the F/2 medium resulted in a significantly higher dry weight content of C. Vulgaris compared to other treatments. It was noted that there was a 32% increase in dry weight compared to the F/2 medium. By utilizing this alternative culture media, significant cost-effectiveness was achieved compared to the F/2 medium. The production cost of algal biomass using betel fertilizer was observed to be as low as SLR 220 per kg of dry weight. This underscores the economic advantages of employing more affordable nutrient sources for large-scale microalgae cultivation.
Keywords: Micro algae, Bioenergy, Growth medi
A Study on Soil Quality Parameters of Two Urban Wetlands in Colombo District, Sri Lanka
No full textThe biological productivity of urban wetlands and quality of their ecosystem services depends on the health of its soil characteristics. Soil characteristics influence vegetation growth, pollutant buffering potential and watershed protection through regulation and infiltration. Assessment of soil characteristics is therefore required for effective management of urban wetlands, particularly of those undergoing restoration. However, in Sri Lanka, limited studies have focused on soil health in urban wetlands. The study evaluated the soil characteristics of two wetlands in the Colombo district: the Green Isle urban wetland (part of the Bellanwila-Attidiya sanctuary), a site currently undergoing restoration, and the Beddagana urban wetland, a successfully restored site (part of the Colombo Ramsar wetland complex). The main objective was to compare the soil characteristics in two urban wetland sites that differed in restoration status. Soil samples were taken at depths of 0-40 cm from the surface, with five replicates collected from each of the four plots at Green Isle and five plots (25 m2 area each) at Beddagana wetland sites. Eleven soil parameters; temperature, moisture, pH value, electrical conductivity, bulk density, organic matter, nitrate, phosphorus, potassium, texture, and color were determined through field and laboratory investigations over a 3-month period (December 2022 – February 2023). Data analysis using two-way ANOVA (R version 4.2.3) revealed significant differences in soil temperature, pH, electrical conductivity, nitrate, and phosphorus content between the two urban wetland sites over the period. The principal component analysis identified electrical conductivity, soil temperature, and soil nutrients as key factors distinguishing the soil samples of the two sites, along with the difference in soil pH value. The Beddagana urban wetland had a loamy soil, and the Green Isle site had a higher clay content. On the Simple Additive Soil Quality Index (SQI), the Beddagana site exhibited higher soil quality (SQI=5.67) compared to the Green Isle site (SQI=4.96). The significantly higher value for conductivity and nitrate of the Green Isle site could be due to waste disposal from surrounding urban areas while the higher temperature would be a result of the lower vegetation cover in comparison to the Baddegana site. In conclusion, the SQI indicates that the restored Beddagana urban wetland has higher soil quality than the Green Isle urban wetland, which is still undergoing restoration. This validates its use in further studies to assess restoration status of urban tropical wetlands. The study shows the importance of assessing specific soil characteristics such as electrical conductivity when restoring degraded urban wetlands and the role of soil properties in understanding disturbances.
Keywords: Urban wetlands, Soil quality parameters, Restored wetlands, Soil nutrient
Cover Page and Preliminary Pages
No full textNEXUS OF SUSTAINABILITY, INNOVATION AND EXPORT PERFORMANCE: A STUDY OF BOI INDUSTRIAL EXPORTING FIRMS IN SRI LANKA by Karunaratne H.D.M.T. and Dunusinghe P.
THE IMPORTANCE OF STOICISM IN EMPOWERING PEOPLE FOR ECONOMIC RECOVERY IN SRI LANKA: A CONCEPTUAL FRAMEWORK by Walgama K.H.
DOES GENDER-BASED OCCUPATIONAL SEGREGATION AFFECT EMPLOYEES’ EARNINGS AND LABOUR SUPPLY IN SRI LANKA? by Madushika P.G.H. and Samaraweera G.R.S.R.C.
PUBLIC DEBT DYNAMICS AND EXCHANGE RATE IN NIGERIA by Kuranga A.O., Afolabi A.C., Jimoh M.M. and Ojuolape M.A.
HOW WE COME TO BELIEVE: A CONCEPTUAL EXPLORATION OF POLITICAL IDEOLOGY FORMATION by Tennakoon S.M.A.V.S. and Wattegama W.G.E.J.
THE NEXUS BETWEEN OIL PRICES AND EXCHANGE RATE: EVIDENCE FROM NIGERIA by Alabi M.K. and Oladehinde H.O
Development of a Framework for Evaluating Farm Sustainability in Sri Lanka
Get PDFIndicator-based sustainability monitoring tools are frequently employed worldwide for sustainability assessments, including agriculture and farm systems. However, that were developed especially for Western agricultural systems. Existing international sustainability frameworks developed especially for Western agricultural systems do not address Sri Lanka's unique environmental, economic, and social aspects. This study aims to bridge this gap by developing a comprehensive rating system framework that integrates sustainability principles for local farms, including horticulture, plantation, and organic farms. Literature review and stakeholder perspectives are the beginning of the study to establish primary criteria for the framework. Through a stakeholder survey, these criteria are then validated for suitability in the Sri Lankan context. Sub-criteria are defined for each approved criterion. Sub-criteria include national and international industry standards, government legislation, and relevant benchmarks applicable to Sri Lanka. The framework is validated further through interviews with technical committees and the points for each criterion are determined using the Analytical Hierarchy Process (AHP) mathematical decision-making method. A pilot study tests the practicability of the study. The final rating system contains six main criteria with relevant sub-criteria: Management, Integrated Cultivation Management, Water Efficiency, Energy Efficiency, Waste Management, and Social Responsibilities and Awareness. According to the AHP results, the weightage of the criteria is as follows: Integrated Cultivation Management (23%), Water Efficiency (19%), Management (17%), Waste Management (16%), Energy Efficiency (15%), and Social Responsibilities and Awareness (10%). The pilot study on an organic farm in Piliyandalaachieves 65 points out of a possible 100. This verified sustainability framework served as a tool to enhance or establish sustainable practices within Sri Lanka's agriculture farm sector.
 
A Review of Numerical Simulation Advances and The Role in Evaluating Erosion Control and Shoreline Management
Get PDFNumerical simulations are crucial in coastal management, serving a key function similar to their role in other engineering disciplines. They deliver crucial insights into complex coastal dynamics, including erosion, which is affected by factors such as climate change, sea level rise, and human interventions. Using a bibliometric analysis approach, this study assesses the evolution and future trends of numerical simulation applications for coastal erosion and shoreline management actions. By exploring databases like Scopus and Google Scholar and visualizing key data with VOSviewer, the research identified publication trends, citation metrics, and emerging study areas. The analysis reveals a substantial increase in relevant research over the past decade, with a notable surge in activity post-2018. The identified key advancements include the integration of Digital Elevation Models (DEM), machine learning, and process-based modeling, all of which significantly enhance simulation accuracy and predictive capabilities. Further, a comparative analysis of models including Delft 3D, SWAN, XBeach, and MIKE underscores their unique strengths and highlights the importance of selecting appropriate models based on specific project conditions. The study concludes that multidisciplinary parameters integrated with technological advancements are crucial for developing effective and sustainable coastal management strategies, emphasizing the need for model selection tailored to address specific erosion and shoreline management project needs
Optimising Robot Manipulator Inverse Kinematics with Genetic Algorithm
Get PDFAs traditional, robot manipulator inverse kinematics solutions are computationally intensive, numerous algorithms has been introduced to minimize the time required to compute inverse kinematics. In this paper an Artificial Neural Network (ANN) was utilized to solve the inverse kinematics of a robot manipulator, and a Genetic Algorithm (GA) was used to optimize the ANN weights and biases. This research primarily examined how crossover and mutation variation affect inverse kinematics problems solved with a GA optimised ANN model. In GA optimisation, single point and two-point crossover were performed to test the crossover effects while Gaussian and uniform mutations were used in the mutation. The ANN GA optimised inverse kinematics model was trained and tested using the Forward Kinematics data set. The single point crossover and Gaussian mutation produced the best results based on the results for the generated data. In conclusion GA can be used with variety of parameters to achieve optimal results which may differ depending on the parameters chosen