Browsing by Author "Edirisinghe, D"

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item: Conference-Full-text
comparative study on cure, mechanical and dynamic-mechanical properties of natural rubber compounds formulated with dixp, tbztd, zbec and tbbs accelerators
(IEEE, 2021-07) Samarasinghe, H; Walpalage, S; Edirisinghe, D; Egodage, S; Adhikariwatte, W; Rathnayake, M; Hemachandra, K
Today, it is obligatory to replace nitrosamine releasing traditional accelerators owing to the various health, safety and environment regulations and surviving with safe alternative is a one of the key challenges in the rubber industry. In this work four groups of commercially available nitrosamine free/safe accelerators were selected, i,e., diisopropyl xanthogen polysulfide (DIXP), tetrabenzyl thiuramdisulfide (TBzTD), zinc dibenzyl dithiocarbamate (ZBeC) and N-tert-butyl-2-benzothiazole sulfenamide (TBBS). The effect of accelerator type on cure, crosslink density, physico-mechanical and dynamic-mechanical properties of efficient sulfur vulcanized natural rubber (NR) compounds was investigated. Results reveal that accelerator type does not only affect the cure characteristics, but also has a great impact on physical and mechanical properties, DIXP possess the least modulus and strength properties while providing satisfactory optimum cure time for the vulcanization compared to the TBBS accelerator. Improvement in mechanical properties is observed in the order ZBeC, TBzTD, TBBS and corroborates well with the crosslink density. ZBeC and TBzTD show relatively higher hardness, storage modulus and lower hysteresis in the rubbery region indicating different microstructure arrangement compared to commonly use of non-regulated nitrosamine safe TBBS accelerated vulcanizates.
item: Conference-Abstract
Exploring the elements of urban metarmophosis that sustain the place integrity of historic urban centres : the case study of Slave Island, Colombo
Edirisinghe, D; Wijesundara, J
Cities around the world have experienced unprecedented changes in their economy, environment and society due to rapid globalization and urbanization. Contemporary colonial cities of South Asian countries are dynamic, rapidly growing and continuously changing. Thus, urban transformations and mutations are not a new phenomenon, but rather a continuous process. A historic city and its heritage enables people to better understand previous generations and the history of where they came from, and offer place integrity and unity in the city. The study scoped within the discussion of urban metamorphosis in relation to morphological elements in Slave Island. Slave island is a Colonial city with vast collection of old buildings, yet serves as a home to all aspects of social and cultural urban life. It is an example for “Utilitarian architecture” where it comprises different kind of structures, designed and built by architects and non- architects in public and private spaces. This bustle commercial hub which has a dominant character of urban transformation where it sustains the historic authenticity while responding to urbanization. In such cases population of communities endures place integrity in the heart of old city. The objective of this study is to examine the engagement of social activities in development which incited place integrity. Further it aims to study the factors which preserved within the historical setting in relation to the elements of urban metamorphosis. The urban mutations of the existing physical structures have interconnections with social, economic, cultural and other aspects. Continuous urban growth, diversified activities, and social perception will always mutate the cities. Certain parameters have taken to measure Place integrity and identified the sense of place to analysis the sustained historic authenticity of this situation. Further the research has identified socio-cultural relationship of transforming urban setting.
item: Conference-Full-text
exploring the elements of urban metarmophosis that sustain the place integrity of historic urban centres: the case study of Slave Island, Colombo
(Department of Architecture, University of Moratuwa, Sri Lanka, 2017-10-20) Edirisinghe, D; Wijesundara, J; Wijesundara, J; Dayaratne, R
Cities around the world have experienced unprecedented changes in their economy, environment and society due to rapid globalization and urbanization. Contemporary colonial cities of South Asian countries are dynamic, rapidly growing and continuously changing. Thus, urban transformations and mutations are not a new phenomenon, but rather a continuous process. A historic city and its heritage enables people to better understand previous generations and the history of where they came from, and offer place integrity and unity in the city. The study scoped within the discussion of urban metamorphosis in relation to morphological elements in Slave Island. Slave island is a Colonial city with vast collection of old buildings, yet serves as a home to all aspects of social and cultural urban life. It is an example for “Utilitarian architecture” where it comprises different kind of structures, designed and built by architects and non- architects in public and private spaces. This bustle commercial hub which has a dominant character of urban transformation where it sustains the historic authenticity while responding to urbanization. In such cases population of communities endures place integrity in the heart of old city. The objective of this study is to examine the engagement of social activities in development which incited place integrity. Further it aims to study the factors which preserved within the historical setting in relation to the elements of urban metamorphosis. The urban mutations of the existing physical structures have interconnections with social, economic, cultural and other aspects. Continuous urban growth, diversified activities, and social perception will always mutate the cities. Certain parameters have taken to measure Place integrity and identified the sense of place to analysis the sustained historic authenticity of this situation. Further the research has identified socio-cultural relationship of transforming urban setting.
item: Thesis-Abstract
Investigation of the technical properties of the tyre re-treading compund formulated with RSS/SCRAP rubber blends
Alahapperuma, KG; Subramanium, K; Edirisinghe, D
Due to higher demand of petroleum and petroleum based synthetic rubbers, the price of Ribbed Smoked Sheets (RSS) has been gone up. Therefore, local rubber industries, particularly re-treading tyre industry has started replacing RSS grade partly with a cheaper scrap grade of Natural Rubber (NR) in their re-treading tyre compounds, in arbitrary ratios without considering the quality of tyre treads. In the project work, the tyre re-treading compounds based on blends of (RSS) and scrap grade in different proportions are investigated to identify the most suitable blend for obtaining optimum technical properties. The first step of the study reveals that the blend having RSS and scrap rubber in the ratio 80 : 20 is the most suitable economical blend to obtain a balance of technical properties . To get the optimum technical properties of the re-treading tyre compounds, the amount of carbon black should be added separately into the two types of rubber and prepared in the form of master batches, prior to mixing the two types of rubber together. Different weight. ratios are used for the two portions and correspondingly different compounds are prepared. The second step of the project work reveals that the addition of carbon black-oil mix should be made separately into each grade of rubber (of the chosen formulation from the first step of the project work), preferably 80% by weight t~ RSS and 20% by weight to scrap rubber, for optimum quality tyre treads Further increase of carbon black in scrap rubber is observed to give deleterious effects on both, cure and vulcanisate properties, due to non uniform dispersion of carbon black in scrap, possibly due to higher loading of carbon black in scrap rubber
item: Conference-Abstract
Nutrient recovery from food industry solid waste for cultivation of the microalga Desmodesmus sp. for production of alpha-linolenic acid
(Department of Chemical & Process Engineering University of Moratuwa., 2023-08-17) Dayanath, WMS; Edirisinghe, D; Ariyadasa, TU; Walpalage, S; Gunawardena, S; Narayana, M; Gunasekera, M
The generation of food waste by the food processing industry poses significant environmental and economic challenges globally. This study investigated the potential of utilizing industrial food waste as a source of nutrients for cultivation of the microalga Desmodesmus sp. to produce value-added biomass rich in alpha-linolenic acid. The objectives of the study were to identify the type of food waste and dilution factor of food waste hydrolysate to maximize biomass and alpha-linolenic acid yields, and assess the efficacy of nutrient recovery. The current study is the first in reported literature to utilize industrial food waste for synthesis of microalgae-based alpha-linolenic acid. First, a screening experiment was performed for growth of Desmodesmus sp. in hydrolysates of brewery waste (BrW), biscuit waste (BiW), and Thriposha waste (TW) with four dilution factors; 25%, 50%, 75% and 100% (undiluted hydrolysate). Higher biomass yields were achieved in all waste types compared to the control medium (modified Bold’s Basal media; 3N-BBM), with the maximum yield obtained using 100% TW. Thereafter, Desmodesmus sp. was cultured in photobioreactors using 100% TW, with a 3N-BBM control. The biomass growth rate and specific growth rate achieved in 100% TW hydrolysate were 0.503 g L d and 0.214 d respectively, which were significantly higher than the control. Biomass analysis showed that a significantly higher lipid content was present in the 100% TW-cultivated biomass, suggesting a higher alpha-linolenic acid extraction potential. Nevertheless, further research on techno-economic feasibility assessment and toxicology analysis is required prior to large-scale adoption of this process.