Institutional-Repository, University of Moratuwa
Welcome to the University of Moratuwa Digital Repository, which houses postgraduate theses and dissertations, research articles presented at conferences by faculties and departments, university-published journal articles and research publications authored by academic staff. This online repository stores, preserves and distributes the University's scholarly work. This service allows University members to share their research with a larger audience.
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Recent Submissions
item: Conference-Abstract
Development of LDH-MOF-5-based tunable active sites of metal nodes (Mo|Mn|Sn|Ag) for the efficient transesterification of picochlorum oklahomense lipids for biodiesel production
(2026) Mrinal; Jaiswal, KK; Rajapakse, RLHL; Prasath, RA
The structural properties of metal-organic frameworks (MOFs) enhance the catalytic activity of the metal centers, which interact effectively with lipid molecules during transesterification. In this research, sustainable LDH-MOFs with tunable active sites at the metal nodes (Mo|Mn|Sn|Ag) were synthesized using terephthalic acid as the organic ligand and Zn-Co LDH. XRD revealed the presence of dominant, highly crystalline phases that preserved MOF structures. UV-visible spectra showed ligand-to-metal charge transfer accompanied by weak d-d transitions at the metal centers. FE-SEM micrographs revealed microflower, needles, and flake-like structures in the MOFs. The optimized conditions were employed to investigate the catalytic performance of the prepared MOFs in the transesterification of Picochlorum oklahomense lipids. Biodiesel conversion efficiencies are to be 89.2% (MOF-BL-Mo), 88.0% (MOF-BLMn), 80.0% (MOF-BL-Sn), 73.7% (MOF-BL-Ag), and 60.0% (pristine LDH), with major composition of FAMEs of palmitic acid (C16:0) and oleic acid (C18:1). The enhanced activity could be attributed to the synergistic effect of the MOF's porous structure, the Zn-Co LDH layers, and the catalytically active sites at the metal nodes, which enable stronger interactions between the catalyst and the lipid molecules. Therefore, the key findings demonstrate the potential of LDH-MOFs with green metal nodes as effective heterogeneous catalysts for the sustainable, high-yield production of microalgal biodiesel.
item: Conference-Abstract
Predictive AI and reinforcement learning for autonomous microgrid energy management in rural areas
(2026) Sharma, A; Petau, J; Ravikiran; Jayaramu, R; Klepp, GH; Shamsundar, S; Rajapakse, RLHL; Prasath, RA
Rural microgrids incorporating solar, wind, and battery storage frequently rely on rigid, rule-based edge controllers for energy distribution. These static IF/THEN systems react only to immediate electrical states and fail to anticipate upcoming meteorological changes, leading to suboptimal energy routing and accelerated battery degradation. This paper proposes a novel machine learning architecture to replace conventional reactive logic with a predictive and autonomous energy management system. By extracting and merging historical minute-resolution telemetry logs from baseline microgrid hardware installed at Mysuru, India, with synchronized retroactive satellite weather data (e.g., NASA POWER), a comprehensive training dataset is established. A deep learning sequence model, utilizing architectures such as LSTM or Transformer, is developed to accurately forecast short-term renewable generation and local power demand. Simultaneously, a Reinforcement Learning (RL) agent, employing Proximal Policy Optimization (PPO), is trained in a custom virtual environment to act as an autonomous energy router. Deployed on a localized edge device (Raspberry Pi) communicating via an MQTT broker, the system dynamically optimizes power distribution in real-time through GPIO control signals. This predictive AI system aims to maximize renewable energy efficiency, offering a scalable blueprint for resilient off-grid rural communities.
item: Conference-Abstract
Microstructural changes during regeneration of plaster of Paris using discarded moulds
(2026) Thilakarathne, KNP; Rukmal, BPT; Ariyaratne, TAMP; Karunaratne, BA; Rajapakse, RLHL; Prasath, RA
Recycling discarded plaster of Paris (POP) molds has gained increasing importance due to environmental concerns and the need for sustainable utilization of gypsum resources. Previous studies have primarily focused on the recycling methods and improvements in macroscopic properties. This study examines the generation of spent POP molds, emphasizing microstructural changes induced by controlled thermal treatment followed by mechanical reprocessing to obtain regenerated calcium sulfate hemihydrate. The elemental composition of commercial and recycled POP was analyzed using Energy Dispersive X-ray Spectroscopy (EDX). Particle size distribution was evaluated using sieve analysis and laser-based particle size measurement techniques. Mechanical performance was assessed through compressive and flexural strength tests conducted using a Universal Testing Machine (UTM). Micro-structural characteristics, crystal morphology associated with β-calcium sulfate hemihydrate, were examined using Scanning Electron Microscopy (SEM). Functional properties were evaluated through water absorption tests, determination of moisture content using a moisture analyzer, and assessment of setting behavior, setting kinetics were characterized by monitoring temperature evolution during hydration, with maximum exothermic temperature serving as an indicator of material reactivity. Microstructural investigations revealed that mainly irregular-shaped particles were present in the used molds, while the treated material contains elongated particles. Investigations revealed that the micro-structural characteristics and physical and chemical properties of the resulting product confirmed the standard requirements of commercial-grade Plaster of Paris and complied with the specifications, despite a minor reduction in mechanical strength.
item: Conference-Abstract
Advantages of integrating circular economy concepts in promoting sustainable construction
(2026) Rajasekara, CV; Samararathne, UMS; Kawmudi, WN; Rajapakse, RLHL; Prasath, RA
Greenhouse gas emissions, trash production, and resource use are all heavily influenced by the building sector. Ecosystem degradation and increased demand for natural resources are driven by the conventional linear "take-make-dispose" approach. As a result, incorporating Circular Economy (CE) principles provides a sustainable substitute that prioritizes material reduction, resource efficiency, reuse, recycling, and the extension of material lifecycles. With a particular focus on the environmental, economic, and social dimensions of the Sri Lankan construction industry, this study investigates the benefits of implementing CE principles for promoting sustainable construction. To get information on this integration, a questionnaire survey was given to professionals in the field, such as contractors, consultants, quantity surveyors, engineers, architects, project managers, and other stakeholders. A total of 111 valid responses were obtained from a total of 120 surveys. The Relative Importance Index (RII) was used to rank the benefits of adopting Circular Economy practices, which were found to have significant positive effects on the environment, the economy, and society. In terms of the environment, cutting greenhouse gas emissions associated with transportation, manufacturing, and material extraction had the highest RII value of 0.782. With an RII rating of 0.764, maximizing resource efficiency for cost reduction was ranked highest economically. The greatest social benefit was found to be the encouragement of fair access to resources and careful resource management. The results show that by reducing environmental effects, maximizing resources and economic efficiency, and promoting social sustainability, Circular Economy principles greatly improve sustainable construction. Raising awareness, working together, and putting these ideas into practice are crucial to helping Sri Lanka's construction sector shift to a more sustainable and resource-efficient model.
item: Conference-Abstract
Footprint and resource decoupling in South Asian economies: a panel data approach
(2026) Abeyrathne, HML; Rajapakse, RLHL; Prasath, RA
The continuous economic growth that South Asia has experienced during the last three decades has been characterized by urbanization, industrial sector expansion, and increased material extraction and consumption, but there have been doubts over whether the development strategy adopted by this part of the world is sustainable in the long run, while empirical studies on resource decoupling in South Asian economies have been few, with most existing studies focused on high-income OECD contexts. This paper attempts to fill that void by analysing the level and determinants of resource decoupling in SAARC countries from the period of 1995 to 2025 using the panel data approach where the material footprint per capita, obtained from the UNEP Global Material Flows Database, serves as the dependent variable, while GDP per capita and its square, industrial value added, trade openness, and governance quality (World Governance Indicators) serve as the independent variables driven from the World Development Indicators. Fixed effect panel regression analysis, which is confirmed by the Hausman test, was performed to address the presence of unobserved country heterogeneity; decoupling status was determined based on the growth elasticity of material footprint. Based on the results, it is clear that most economies in South Asia display relative and not absolute decoupling, where good institutional quality is related to higher success, industrialization with resource-intensive approach correlates with poor results, and openness of economies in terms of trade has been revealed to have a mixed influence. These results imply that institutional capacity and structure, not growth by itself, determine the speed of decoupling, providing insights for policymakers regarding fiscal, institutional, and regulatory structures to achieve resource-efficient and circular growth.