Browsing by Author "Perera, H"

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    Consumption of chilled water stored in a PET bottle multiple times: are we quenching thirst or gulping phthalates?
    (2021) Jayaweera, M; Perera, H; Dhanushika, G; Gunawardane, B
    The statistics forecast that the production of polyethylene terephthalate (PET) bottles worldwide in 2016 was about 485 billion, and the same in 2021, has been approximately 583 billion. Although such productions in many countries have the ear of prominent political and social leaders, high production rates still reign the global market. In parallel, revered scientists globally conflate plausible and incontrovertible medical canons against the use of PET bottles for the protection of public health.
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    Grappling with COVID-19 by imposing and lifting non-pharmaceutical interventions in Sri Lanka: A modeling perspective
    (Elsevier, 2021) Jayaweera, M; Dannangoda, C; Dilshan, D; Dissanayake, J; Perera, H; Manatunge, J; Gunawardana, B
    Jayaweera, M., Dannangoda, C., Dilshan, D., Dissanayake, J., Perera, H., Manatunge, J., & Gunawardana, B. (2021). Grappling with COVID-19 by imposing and lifting non-pharmaceutical interventions in Sri Lanka: A modeling perspective. Infectious Disease Modelling, 6, 820–831. https://doi.org/10.1016/j.idm.2021.06.004
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    Manufacturing of floor tiles using plastic waste and agricultural waste
    (Department of Chemical and Process Engineering, University of Moratuwa, 2019) Hussain, H; Perera, H; Premachandra, BAJK; Rathnasiri, PG
    Floor tiles are the most common and widely used construction and building material around the world. Most of the plastic wastes are non-bio degradable and it takes a long time to deteriorate. Even though agricultural wastes are bio degradable, it also takes a longer period of time to degrade. As a solution for environmental pollution, it was decided to manufacture a floor tile using plastic wastes and agricultural wastes. For this research, rice husk and HDPE were selected as raw materials. By varying the weight ratios of rice husk, suitable floor tile samples were obtained which tallies with the standard floor tile properties.
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    Migration of phthalates from PET water bottle in events of repeated uses and associated risk assessment
    (2020) Jayaweera, M; Perera, H; Bandara, N; Danushika, G; Gunawardana, B; Somaratne, C; Manatunge, J; Zoysa, K; Thathsara, T
    Phthalates are widely used as a plasticizer in manufacturing polyethylene terephthalate (PET) bottles to improve softness, flexibility, durability, longevity, and workability. Phthalates are known in instigating profound human health hazards. In many developing countries, lack of proper disposal facilities established for empty PET bottles and the absence of legislation on reuse invariably persuade people to reuse them for storing potable water. An experiment was conducted with two commercial brands of PET bottles to explore the potential of phthalate migration when domestically refilled and reused in multiple times at two temperature conditions. Temperatures of ambient (27 ± 2 °C) and warm (60 ± 2 °C) were selected as the refilling temperatures because of the common practice by people. For both brands, only bis(2-ethylhexyl) phthalate (DEHP) levels were detected in refilled water in every event of reuse. For both brands, mean DEHP levels migrated to water at 60 ± 2 °C were significantly higher (p < 0.05) compared to those at 27 ± 2 °C. Risk analyses carried out on human health suggested that there exist no definite acute or chronic health risks when the refilled water is consumed continuously for 30 years for both temperatures. Still, such risks were higher for the consumption of refilled water of warm temperatures than those of ambient temperature. However, this study elucidates that DEHP migration would be at an alarming rate when the events of reuse of a single bottle increase so that regulations banning the reuse of empty PET bottles are paramount, especially for developing countries.
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    The Relationship between Psychological distress and human computer interaction arameters : linear or non-linear?
    (2015-07-15) Karunaratne, I; Atukorale, AS; Perera, H
    During a survey based study, it has been revealed that psychological distress is reflected in theway computer users interact with computers. Based on the feedback of the subjects, the typesof stress-reflector interactions were also identified. However, the specific interactions relatedto the stress, the nature of the relationship between the identified‘stress-reflectors’and theactual level of psychological distress was yet to be investigated. Accordingly, the initialsurvey was then followed by a series of activities with the objective of uncovering the natureof the relationship exists between the two. Initially, the most frequented interaction behaviorsof computer users under stress were identified. Secondly these behaviors were recorded usinga background analyzer together with a simultaneous measure of the distress level of therelevant computer user. Finally, behavior measures of individuals were mapped with theirpersonal distress scores, producing the dataset using which the nature of correlations wereexplored. This paper presents the work carried out during this exploration, keeping theinitial focus on linear methods, and provides justifications for the claim: The relationshipbetween the distress score and the human computer interaction parameters is non-linear