Browsing by Author "Jayasinghe, G.Y."

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Assessment of different nutrient levels to optimize the efficiency of rice straw biomethanation and microbial study of their by-products
(2003) Jayasinghe, G.Y.
Coal Fly Ash as an Alternative Substrate to Replace River Sand in Cement Mortar Mixture
(Faculty of Computing and Technology, University of Kelaniya, Sri Lanka., 2017) Jayaweera, N.J.S.T.; De Silva, P.; Herath, H.M.P.I.K.; Jayasinghe, G.Y.
Coal is the most extensively used primary source of energy that accounts globally for 25% of total energy consumption. The global generation of coal fly ash (CFA) is estimated to be above 6x108 Mg per annum and its recycling rate is rather low (15%). Sri Lanka is also facing major economic and environmental problems of disposing CFA from Norochcholai thermal power plant and part of CFA disposal is being used as a raw material for cement production. However, CFA with high loss on ignition (LOI) values cannot be used for blending with cement and this study was designed to investigate the potential utilization of high LOI-CFA as an alternative substrate to river sand in cement mortar preparation. Compressive Strength (CS), water demand (WD), moisture content (MC), initial setting time (IST), and final setting time (FST) were examined to select the most suitable mixing ratio of CFA and river sand. Treatments were prepared in accordance with SLS ISO 1253−107: part 2−2008, with 30 replicates for LOI and MC. Treatments were defined as the percentage of added CFA into sand as T1=0 (control), T2=5%, T3=10%, T4=12%, T5=15%, T6=18%, T7=20%, and T8=25%. Four replicates per each treatment in different three ages (one day−1D, seven days−7D, and twenty-eight days−28D) were tested for CS of mortar in accordance with SLS ISO 679:2008. Initial and final setting time of cement CFA mixture was determined in accordance with SLS ISO 9597:2008(E) with 8 treatments. Results have proven that high LOI-CFA can be used as an alternative substrate to sand up to 20%. The average CS for 1D, 7D, and 28D of control treatment were 16.8 MPa, 41.3 MPa, and 51.3 MPa respectively. The highest CS for 1D (21.9 MPa) and 28D (71.1 MPa) were given by 10% CFA treatment, but the highest seven-day CS results (50.1 MPa) was given by 12% CFA treatment. Each treatment was significantly different from other treatments. Means for CS of T2, T3, T4, T5, T6 and T7 were not significantly different from the mean of control treatment, while T8 (25% CFA and 75% sand) was significantly different from the control. R2 between WD and CFA percentage obtained by regression analysis was 93.2%, which showed a strong relationship between them. R2 of IST versus WD, and FST versus WD were 97.7 % and 94.8 % respectively, which showed strong relationships with WD. Hence, it can be concluded that increasing CFA percentage up to 20, gave increased WD, IST, and FST.
Comparative assessment of biomass and furnace oil fired boilers’ flue gas emission and its environmental impacts.
(International Research Symposium on Pure and Applied Sciences, 2017 Faculty of Science, University of Kelaniya, Sri Lanka., 2017) Silva, G.K.A.D.; Jayasinghe, K.T.; Herath, H.M.P.I.K.; Jayasinghe, G.Y.
Boilers are the significant energy users of industrial production processes where it generates emissions of different air pollutants. This study assessed the comparison between biomass fired and furnace oil fired boiler emissions in the industrial sector of Sri Lanka with the objective of estimating and analyzing the CO2 and the other toxic gaseous emissions (SO2, NO2, CO etc.) released by both boilers. Emission samples from selected different industries have been undertaken by using “In-stack Filtration Method” with Stack Monitoring Kit−Envirotech APM 621. Eight boilers per each boiler types were used for the study and three replicate samples from each boiler were collected. In this method, particulate matter (PM) was withdrawn isokinetically from the source and collected on a glass fiber filter maintained at 105−1400C. The Flue Gas Analyzer –KM 9106 was used to examine the gaseous emissions of nitrogen dioxides (NO2), sulfur dioxides (SO2), carbon monoxides (CO) and carbon dioxides (CO2) by extractive sampling method. Conditioned gas was passed through different chemical sensors (in built sensors) for required reactions. The composition of particular gaseous components were measured based on the number of electrons emitted by different chemical reactions according to International Standards Organization’s (ISO) standard methods. Results from two sampled t-test revealed that furnace oil fired boilers were significantly higher (P<0.05; P=0.02 and 0.001, respectively) in emitting SO2 (1536.25 mg/Nm3) and NO2 (228 mg/Nm3) gases compared to biomass fired boilers (i.e. SO2=410 mg/Nm3 and NO2 =175 mg/Nm3). Carbon monoxide (42.875 mg/Nm3) and PM (58.55 mg/mg/Nm3) concentrations were significantly higher in biomass fired boilers than that of furnace oil fired boilers (i.e. CO = 12 mg/Nm3 and PM =33.625 mg/Nm3). CO2 emission was also significantly higher in biomass fired boilers than furnace oil boilers (i.e.in biomass CO2= 13.5 and in furnace oil CO2=8.5 mg/Nm3 respectively). It can be suggested that extra precautions should be taken to reduce concentrations of CO and PM from biomass fired boilers and SO2 and NO2 from furnace oil fired boilers.
A systematic literature review on integrating disaster risk reduction (DRR) in sustainable tourism (SusT): Conceptual framework for enhancing resilience and minimizing environmental impacts
(Elsevier, 2024) Jayasinghe, G.Y.; Perera, T.A.N.T.; Perera, H.A.T.N.; Karunarathne, H.D.; Manawadu, L.; Weerasinghe, V.P.A.; Sewwandi, B.G.N.; Haroon, M.H.; Malalgoda, Chamindi; Amaratunga, Dilanthi; Haigh, Richard
This literature review meticulously explores the integration of Disaster Risk Reduction (DRR) techniques into sustainable tourism (SusT), placing a focal point on enhancing resilience and mitigating environmental impacts. By examining several disciplines, including tourism management, disaster management, environmental science, green innovation, and sustainable development, this study recognizes major themes, research gaps, and best practices in this emerging subject. It underlines the importance of SusT and the need for effective DRR programs to alleviate the negative effects of catastrophes on tourism destinations and ensure their long-term sustainability and resilience. Science Direct, Springer, SAGE Publications, and Wiley's online library were the selected databases and the inclusion criteria were based on studies that looked at how DRR measures were implemented in SusT practices and how effective they were in increasing resilience and lowering environmental effects. The selected literature reveals many concepts and ways for integrating DRR in tourism, such as pre-disaster planning, risk assessment, capacity building, and stakeholder involvement. The assessment identifies the vital part played by government agencies, local entities, and tourist service providers in organizing and coordinating these programs. It points out potential obstacles to DRR integration within the tourism sector. The review emphasizes the importance of monitoring and measuring the outcomes of DRR programs in tourism, and it suggests the use of metrics and indicators to assess how well resilience-building and environmental impact reduction strategies are implemented. These insights may be utilized by policymakers, academics, and practitioners to design methods that enhnace the resilience of tourism destinations while minimizing environmental consequences.conditions in Sri Lankan marine waters, thus qualifying mangrove ecosystems in microtidal coasts as effective carbon sinks.