http://dr.lib.sjp.ac.lk/handle/123456789/1139 2026-01-07T06:16:25Z http://dr.lib.sjp.ac.lk/handle/123456789/12726 SYNTHESIS AND CHARACTERIZATION OF CERAMIC COMPOSITES DERIVED FROM EPPAWALA APATITE FOR AUTOMOTIVE AND INDUSTRIAL APPLICATIONS Hapuhinna, H.K.G.K.D.K The Sri Lankan Eppawala rock phosphate deposit, found in the North Central province, is a non-renewable natural resource that does not replenish over humanly meaningful time scales. It contains nearly 34% to 40% phosphorous pentoxide (P2O5). Even though there are numerous viable and value-added phosphorous (P) industries, Sri Lanka exports rock phosphate as a raw material at lower prices to other developed nations. Considering its resource-related wealth, it is a timely requirement to obtain the proper compensation for this non-renewable resource. Therefore, it is crucial to consider developing and commercializing fresh P-related finds from the Eppawala rock phosphate deposit. In order to value add Eppawala high-grade rock phosphate (HERP), this dissertation thoroughly and critically discusses three patented innovative processes (sol-gel alcoholic route, solgel acidified route, and solid-state sintering technique) for synthesizing three patented nano-hydroxyapatite (HAp) ceramic varieties. It provides significant insights into processcomposites incorporating those synthesized HAp ceramic varieties withdifferent polymers [methyl methacrylate (MMA), 2-hydroxyethyl methacrylate (HEMA)], polyester, epoxy, glass fibers, silicon carbide (SiC) and boron nitride (BN) which can be used for several biomedical, automotive and industrial applications. Synthesized nanoHAp ceramic varieties and processed HAp incorporated composites were characterized using X-ray fluorescence spectroscopy (XRF), particle size analysis (PSA), X-ray diffraction spectroscopy (XRD), fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM with EDS), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), dynamic mechanical analysis (DMA), tensile tests, and impact tests in order to find out composition, the size distribution of particles, crystallographic structure, identification of functional groups, the morphology of micro/nanostructures, glass transition temperatures, thermal stability, thermomechanical properties, tensile properties, and impact strength. American society for testing and materials (ASTM) standards were applied for all mechanical analyses. This dissertation compared those results with human hard tissues, commercial products, and literature according to their nature of applications. It has been concluded that HAp can be synthesized using the three routes to add value, HERP. These methods are highly cost-effective. Synthesized hexagonal, nano-HAp products perform similarly in chemical composition and structure to mammalian hard tissues via exhibiting different characteristics as bioceramic. The resulting composite materials obtained after reinforcing hydroxyapatite ceramic products with MMA and HEMA orderly for orthopedics and dentistry applications have proven that their performances are better than commercial products. It shows the highly profitable possibility of introducing Eppawala HAp products into the market as value-added bioceramic and its composites. Processed HAp incorporated E-glass fiber reinforced polyester matrix composites and ceramic (HAp/SiC/BN) incorporated epoxy matrix composites in this study demonstrate better properties than pure polyester and epoxy materials. Resulted composites can be used for automotive and aircraft applications. Also, it has confirmed the possibility of processing SiC and BN incorporated HAp composites under high temperatures (1600°C-1650°C), for other relevant industrial applications. 2022-01-01T00:00:00Z http://dr.lib.sjp.ac.lk/handle/123456789/12722 The Impact of Agricultural Economy of Periphery on Urban Dynamics in Dry Zone Sri Lanka. Ranaweera, D. D. A. Cities are typically complex notions with multiple dimensions and interpretations. The human landscape in cities is a unique phenomenon that undergoes temporal and spatial changes due mainly to the influence of industrialization, urbanization, and globalization. Among these factors, the nature of the services offered by various urban centers and the periphery of receiving such services generate urban dynamics. A dynamic involves the modification or enhancement of an existing situation. This study aims to identify and analyze the most substantial elements of Dry Zone urban dynamics created by the combination of three components, namely the performance of the periphery, the behavior of the city, and city-using third parties. Under the method of purposive sampling, three urban centers and nine periphery villages were selected for the study based on the mean of all urban service centers. This study used primary and secondary data and they were analyzed using statistical methods, Geospatial techques and qualitative analytical method for styding the dynamics. One of the most important findings of this study is that the functions of the service centers in the Dry Zone are taking precedence over the peripheral requirements. In addition, the distribution of functions of the service centers varies across urban service centers, however the type of functions is comparable. Consequently, the vertical spread of the city is currently faster than its horizontal spread. Although the urban dynamics and the agricultural sector may coexist, it is influenced by numerous other complex aspects. Among such aspects, the tourism business, the trend toward non- agricultural employment, and the shift in mindset produced by the rise in education have been the most prominent. At present it is difficult to measure the urban dynamic with traditional parameters and it is needed to analyze the new factors which are developing in dry zone urban environment, and it could be take at least another 10 years of period to show real picture of the urban dynamics in Dry Zone of Sri Lanka. 2022-01-01T00:00:00Z http://dr.lib.sjp.ac.lk/handle/123456789/12716 Synthesis of bone cement from a natural mineral for biomedical industry Hapuhinna, H.K.G.K.D.K.; Gunaratne, R.D.; Pitawala, H.M.J.C. Study carried to find out chemical and structural suitability of newly synthesized Eppawala Hydroxyapatite composite as bone cement, by comparing and contrasting it with human bone as well as commercially available bone cement, which is currently used in orthopedic surgeries. Therefore, a mixture of commercially available bone cement and its liquid monomer, commercially available Methyl Methacrylate (MMA) and a mixture of Solid State synthesized Eppawala Hydroxyapatite powder with commercially available MMA were prepared as the direct substitution for bone cement. Then physical and chemical properties including composition, crystallinity, presence of functional groups, thermal stability, surface morphology, and microstructural features were examined compared to human bone. Results show there is a close similarity between synthesized product and human bone while credenting high thermal stability, good crystalline, and porous properties than the commercial product. Finally, study concluded newly synthesized composite can be applied directly as a substitution for commercial bone cement. 2019-01-01T00:00:00Z http://dr.lib.sjp.ac.lk/handle/123456789/12714 A novel approach of synthesizing 2-hydroxyethyl methacrylate embedded hydroxyapatite composites for dentistry applications Hapuhinna, H.K.G.K.D.K.; Gunaratne, R.D.; Pitawala, H.M.J.C. This research focused to find out chemical and structural suitability of novel Hydroxyapatite composite synthesized using Chloroapatite and 2-hydroxyethyl methacrylate as Dental filling material. For that, Solid State Sintering technique was used to produce Hydroxyapatite using Sri Lankan Chloroapatite and Calcium hydroxide. After reinforcing it with 2-hydroxyethyl methacrylate, physical and chemical properties were examined via comparing and contrasting it with the human tooth and commercially available Glass Ionomer cement (GIC), used in the field of Dentistry. Results show there is a close similarity between the synthesized product and the human tooth. Therefore, the study concluded that synthesized Hydroxyapatite composite can be used directly as a substitution for commercial dental filling material 2019-01-01T00:00:00Z