Engineeringhttp://ir.kdu.ac.lk/handle/345/50912024-03-29T10:52:15Z2024-03-29T10:52:15ZA Sustainable Future for Rubber Waste in Sri LankaKuruwita Arachchi, VLKulathunga, DDTKhttp://ir.kdu.ac.lk/handle/345/48402023-04-26T11:00:10Z2021-01-01T00:00:00ZA Sustainable Future for Rubber Waste in Sri Lanka
Kuruwita Arachchi, VL; Kulathunga, DDTK
Innovative construction materials have a high demand in the construction industry with the development of the green building concept and sustainable construction. The use of waste materials is encouraged even with the green rating system, and waste rubber is identified as one of the main waste materials generated in any country. Sri Lanka produces 4.5 billion solid waste materials per year. The management of waste material and implementing them in a productive way is essential for a country to promote sustainability. For rubber waste, solutions such as rubberized concrete have been introduced in developed countries. However, in Sri Lanka, rubberized concrete is not popular in the construction industry. Further, it is not clear whether the quality or the quantity of rubber waste available in Sri Lanka is sufficient to promote such application of rubber waste. Therefore, this study reviews the feasibility of using rubber waste available in Sri Lanka for a commercial application such as rubberized concrete. The wastage of rubber from different sources was identified as 1283.6 tons per month in Sri Lanka. Out of the whole batch of rubber wastage, latex rubber and tire rubber wastage were identified as the main types. The quality of rubber wastage is critical when using rubber waste in application. Literature on rubberized concrete suggests recycled crumb rubber and tire chips of 5mm to 20mm in size as suitable for rubberized concrete. Rubber crumbs of this recommended size can be found in Sri Lanka in sufficient amounts, which implies that there is a future for rubberized concrete in Sri Lanka.
2021-01-01T00:00:00ZDrop Down in Speed of Fast Attack CraftLokudadalla, LDTKDhttp://ir.kdu.ac.lk/handle/345/48392023-04-26T11:19:26Z2021-01-01T00:00:00ZDrop Down in Speed of Fast Attack Craft
Lokudadalla, LDTKD
Sri Lanka Naval fleet consists of 55 Fast Attack Craft (FACs) belonging to the Sri Lanka Navy (SLN) and Coast Guard which are propelled by water jets, conventional V-drive propulsion systems, and Articulated Surface Drive (ASD) powered by twin diesel engines. Recently, the drop in speed of FAC’s has been a challenging problem to SLN. The objective of this research is to find out the reasons for the speed drop of FACs, and the effect of hull cleaning/routine underwater maintenance as a solution. The research mainly focused on gathering information related to speed with RPMs and observing changes to the hull, and finally modelling of a similar shaped hull and analysing effects on speed due to the changes in the hull form.
2021-01-01T00:00:00ZSupersaturation Controlled Wet Synthesis of Nanohydroxyapatite for Biological ApplicationsDhananjaya, GSMadusanka, TGDAdikary, SUhttp://ir.kdu.ac.lk/handle/345/48372023-04-26T11:00:28Z2021-01-01T00:00:00ZSupersaturation Controlled Wet Synthesis of Nanohydroxyapatite for Biological Applications
Dhananjaya, GS; Madusanka, TGD; Adikary, SU
In this study, the effect of supersaturation for wet chemical synthesis of Nano-hydroxyapatite HA [Ca10(PO4)6(OH)2] was investigated. The nano-hydroxyapatite powder was synthesized using Ca(OH)2 and H3PO4 as precursors at five different supersaturations while the temperature for the whole study remained at 300C. The supersaturation for hydroxyapatite was caused by changing the concentration of precursors maintaining the constrained molar ratio near 1.67 between Calcium and Phosphorus Ca/P. The H3PO4 was added to the Ca(OH)2 suspension at a constant acid addition rate of 4ml/min using a burette under vigorous stirring having maintained the final pH at 10. During the synthesis, the variation of pH of the mixed precursor suspension was measured and analysed. After 48 h aging, the precipitate was separated by centrifuging at room temperature. Then the resulting wet powder samples were dried and characterized. The particle size distribution was obtained by Laser Particle Size Analyzer and Fourier Transform Infrared (FTIR) spectroscopy investigated the bonding structure of pure hydroxyapatite. In addition to that, morphological and chemical analysis was done by Scanning Electron Microscopy (SEM). As a measurement, the time taken by the final precursor mixture to start reducing pH value increased with the supersaturation decreasing. It was clearly observed that the particle size and the standard deviation of the distribution or a broader distribution had increased with decreasing supersaturation. Finally, this model could be used to predict the particle size distribution of hydroxyapatite resulting from a wet chemical routine with the supersaturation which depends basically upon precursor concentrations.
2021-01-01T00:00:00ZA Methodological Literature Review on Non-Invasive Blood Group DetectionJayawardena, MDVAGhttp://ir.kdu.ac.lk/handle/345/48362023-04-26T11:15:03Z2021-01-01T00:00:00ZA Methodological Literature Review on Non-Invasive Blood Group Detection
Jayawardena, MDVAG
Blood grouping is the method of determining the type of blood inherent in an organism’s body based on the unique types of molecules present in their body- namely antigens and antibodies. Blood groups are differentiated based on the general ABO classification system. Identification of the blood group is a key factor, specifically in the field of healthcare. Organ transplantation and blood transfusion require the blood groups of the individuals to be determined rapidly, in case of diseases or accidents. The standard method of blood grouping requires samples of blood to be extracted from the person, which is then directed for further chemical processing. This conventional method is painful and time-consuming; thus, the introduction of a novel non-invasive method would bring convenience to most humans. The proposed systems have generally used visible light for voltage detection, image processing and deep learning algorithms, NIR spectroscopy, and methods of molecular detection in order to yield results. But limited literature based on this subject exists. Hence, this methodological literature review focuses on the existing peer reviewed literature that explores methods related to noninvasive blood grouping. Out of the methods reviewed, voltage detection using visible light and NIR spectroscopy proved to have the highest rates of success.
2021-01-01T00:00:00Z