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-Full-text
Development of bone scaffold using chitosan nano-hydroxyapatite composite
(IEEE, 2024) Nuwarapaksha, NBN; Perera, DLL; Adikary, SU
Bone defects with critical-size fractures require clinical intervention for fracture healing. Commonly used treatments have limitations like donor morbidity, limited donors, and mechanical mismatches. Bone scaffolds are developed to address these limitations and improve bone formation, vascularized ingrowth, and biodegradability as bone remodels. In this study, bone healing scaffolds have been fabricated using a coprecipitated chitosan-nanohydroxyapatite composite. Fourier-transformed infrared spectroscopy, scanning electron microscopy, energy dispersive x-ray analysis, x-ray diffraction spectroscopy and thermogravimetric analysis were used to analyze the extracted chitosan and composite. Cylinder-shaped bone scaffolds were obtained by freeze-drying the composite with gelatin. Scaffold fabrication experiments were conducted by varying the composite: gelatin ratio for better shape retention and mechanical properties. Bone scaffolds were analyzed for porosity, pore size distribution, compressive strength and in-vitro bio-activity. An optimum composition in terms of shape retention and other required properties was obtained by the scaffold fabricated using 70% composite (Chitosan: nanohydroxyapatite -70:30) and 30% gelatin. This sample had 85% porosity exhibiting a compressive strength of 0.2 MPa that mimics the compressive strength of cancellous bone. The bioactivity of the scaffolds was successfully analyzed by conducting an in vitro biomineralization test for the composite and an in vitro biodegradation test for the scaffold.
item: Conference-Full-text
Spatial autocorrelation analysis of land surface temperature distribution influenced by built areas in the North Central Province of Sri Lanka
(IEEE, 2024) Dassanayake, S; Mahakalanda, I; Prasanna, R R.
Urbanization and population growth have led to increased built-up cover, impervious surfaces, and a decline in vegetated spaces. This has exacerbated the zoning of hightemperature clusters in populated areas. While satellite remote sensing techniques have demonstrated a positive empirical association between impervious surface cover and high-temperature zones, their spatial correlation has yet to be understood. This study assesses the spatial autocorrelation of impervious surface cover and high-temperature zoning in the North Central Province of Sri Lanka using a SAR-based Built-Up Index (BUI) coupled with Sentinel-2 optical imagery indices. Using normalized difference water index (NDWI) and normalized built-up area index (NDBI), land use was visually analyzed and classified. MODIS land surface temperature (LST) maps were employed to estimate surface temperatures. The classified images and LST maps were re-sampled and analyzed using the bivariate Moran’s I index to assess the spatial autocorrelation between BUI and LST values. The analysis reveals spatial anomalies in LST spread near the outskirts of urban areas, water bodies, and green patches, suggesting potential spatial propagation patterns. Zones with high spatial correlation between BUI and LST indicate potential future expansion areas of high-temperature clusters, emphasizing the need for targeted urban planning interventions to mitigate the urban heat islands.
item: Conference-Full-text
Unveiling PEEK’s crystallization kinetics with the hay model: an isothermal DSC study
(IEEE, 2024) Kanchana, PK; Weerasinghe, IU; Amarasinghe, DAS; Attygala, D; Samarasekara, AMPB; Satheekshana, W
This research demonstrates the applicability of the Hay Model, a modified version of the Avrami Model, to analyze the isothermal crystallization kinetics of poly(ether-ether-ketone) (PEEK), a high-performance thermoplastic polymer. While the Hay Model has proven effective for a variety of polymers, its application to PEEK remains unexplored. This research addresses this gap by using isothermal melt crystallization data obtained at temperatures between PEEK's melting and glass transition temperatures, measured through Differential Scanning Calorimetry (DSC). The obtained data is analyzed using both Avrami and Hay Models. The results suggest that the Hay Model is more effective in interpreting isothermal crystallization kinetics of PEEK, as validated with the Kolmogorov-Smirnov test. Then, the Lauritzen-Hoffman theory was also employed alongside the Hay Model to determine temperature-dependent crystallization rates. This study enhances the modeling of polymer processing techniques with PEEK and solidifies the Hay Model as a more effective kinetic model in describing the isothermal crystallization kinetics of PEEK.
item: Thesis-Abstract
The Effect of stock market development and inflation on economic growth in Sri Lanka
(2025) Kumara, HN; Mathugma, S
In the modern financial system, the stock market plays a significant role. Currently, Sri Lanka is recovering from the worst economic crisis in Sri Lankan history. Various studies have been performed worldwide to explore the connection among stock market advancement and the uplift of national economies from diverse perspectives. In Sri Lanka, a limited number of studies were performed. This study aimed to determine the relationship between stock market advancement and economic uplift in Sri Lanka, utilizing four proxies called, market size, efficiency, stability, and accessibility to gauge the stock market's advancement in Sri Lanka. Market capitalization, annual turnover, all share price index, and the number of listed firms in CSE were considered to measure respective proxies and gross domestic product used to measure economic development in Sri Lanka. Annual time series data spanning from 1990 to 2022 were gathered from the Central Bank annual reports and the Colombo Stock Exchange data library for this study. Stock market development measuring proxies provide growth over the period with some significant fluctuations. GDP has increased gradually in the past 3 decades. Principal component analysis was conducted to make a collective measure using stock market development measuring variables which are highly correlated. Johanson's cointegration test indicates the existence of a long-term cointegration relationship among the variables. The Vector Error Correction model was performed to assess the long-term relationship. VECM model results indicate the significant long-term relationship between stock market advancement and economic uplift in Sri Lanka. The short-term causality relationship between variables was assessed using the Granger causality test. The Granger causality test confirms the bi- directional short-term relationship among share market advancement and the uplift of the Sri Lankan economy.
item: Thesis-Abstract
The Impact of USD exchange rate fluctuations and macroeconomic factors on foreign direct investment inflows in Sri Lanka
(2025) Jeewandara, JGN; Dharmarathne, HASG
TheprimaryaimofthisresearchistoinvestigatetheimpactoffluctuationsintheUSD exchange rate (as the U.S. dollar (USD) holds a dominant position in global trade and financial markets) on foreign direct investment inflows into Sri Lanka, placing exchangeratestabilityasacriticalfactorinattractinginvestment. Furthermore,there- search will consider how the fluctuations of other important factors like GDP growth, inflation, and trade openness influence the FDI inflows in Sri Lanka. These variables were chosen based on their theoretical and empirical importance in FDI literature and their relevance to the Sri Lankan economic context. By understanding these factors, thisstudyaimstoprovidecomprehensiveinsightsintotheeconomicfactorsthatinflu- ence FDI inflows especially during times of currency fluctuation.
The analysis establishes both long- and short-run relationships between the iden- tified variables using the Autoregressive Distributed Lag Model (ARDL). ARDL is particularly suitable for this research as it accommodates variables of different levels ofintegration(i.e.,I(0)andI(1)). Thetestresultsindicateapresenceofthelong-runre- lationship between FDI inflows and the selected other variables. In additionally, Error CorrectionModel(ECM)isappliedtoobserveshort-rundynamicsandtheadjustment mechanism toward the equilibrium in the long run. Results from this study show that GDP growth has a positive and significant impact on FDI inflow, both in the short and long run. The error correction term is highly significant with a negative coefficient signifyingthatthespeedofadjustmenttowardthelong-runequilibriumishigh. Inthis respect,itisfoundthatalmost86%ofdisequilibriumiscorrectedinshort-runperiods. The data have been analyzed on the statistical software Eviews. These insights hold significant implications for policymakers, as they highlight the need to stabilize key economic indicators to enhance Sri Lanka’s attractiveness as a destination for foreign investment