Research Papers - Department of Mechanical Engineering

Permanent URI for this collectionhttps://rda.sliit.lk/handle/123456789/604

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    Component part standardization: A way to reduce the life-cycle costs of products
    (Elsevier, 1999-04-20) Perera, H. S. C; Nagarur, N; Tabucanon, M. T
    This paper studies the effects of component part standardization on life-cycle costs. Three possible situations for component standardization are discussed. A summary is presented of various costs in different phases of the product life cycle and how they are shared among the manufacturer, user, and society. Then, we explain how the component standardization reduces the costs of different phases of the product life cycle. Finally, we point out some of the possible disadvantages of component standardization.
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    PublicationOpen Access
    Comfort conditions for built environments in Sri Lanka
    (Institution of Engineers, 1999) Jayasinghe, M.T.R
    The neutral temperatures for different locations in Sri Lanka have been established using actual climatic data. Based on these neutral temperatures, 'standard comfort zone for each of these locations can be identified on the psychrometric chart. Field measurements have been carried out for the validation of comfort zones for Sri Lankan conditions. The effects of physiological cooling at relatively high internal air velocities have been highlighted. In order to check the applicability of standard modification techniques for the comfort zones to take account of elevated internal air velocities, surveys have been carried out at two different velocities. The need for additional boundaries to standard modifications to suit Sri Lankan conditions have been highlighted. This provides a method of extending the boundaries of these comfort zones thereby accommodating higher levels of dry bulb temperatures and humidites in the built environments. This fact can be utilised as the basis of minimising the energy demand in buildings either air conditioned or not, by making use of combined modes at different internal air velocities.
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    PublicationOpen Access
    Passive techniques for residential buildings in low altitudes of Sri Lanka
    (Institution of engineers: Colombo, 1999) Jayasinghe, M.T.R; Attalage, R. A
    The role of passive techniques, which utilises a certain number of passive elements to maintain the thermal comfort within the built environments of residential buildings at low atlitudes of Sri Lanka, has been highlighted. The possibility of defining a unique neutral temperature of 26°C for low altitutes of Sri Lanka has been utilised in a rational way in presenting simplified set of rules of thumb, that can be used by the designers at early stages. The effects of orientation, shading devices, window sizes, roofing materials, insulation, colour of the exterior and interior walls, use of courtyards to maximise natural ventilation, and arrangement of roof to minimise structural cooling are shown with suitable examples.
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    PublicationOpen Access
    Potential of biomass fuel conservation in selected Asian countries
    (Pergamon, 1999-07-01) Bhattacharya, S. C; Attalage, R. A; Leon, M Augustus; Amur, G. Q; Salam, P Abdul; Thanawat, C
    The potential of savings in the biomass consumed for energy in seven Asian countries—China, India, Pakistan, Nepal, Philippines, Sri Lanka and Vietnam—is estimated, if the centuries-old traditional methods of biomass use are reconsidered and an efficient, rational use is implemented. The present pattern and share of biomass consumption of different traditional biomass energy devices are recorded. The efficiency of traditional technologies and that of improved ones—technologies which are practically applicable or already in use somewhere else—are compared and the potential of biomass savings is calculated. The total biomass saving potential in all seven countries together has been estimated at 322 million tons/year
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    PublicationOpen Access
    Potential of biomass fuel conservation in selected Asian countries
    (Pergamon, 1999-07-01) Bhattacharya, S. C; Attalage, R. A; Leon, M Augustus; Amur, G. Q; Salam, P Abdul; Thanawat, C
    The potential of savings in the biomass consumed for energy in seven Asian countries—China, India, Pakistan, Nepal, Philippines, Sri Lanka and Vietnam—is estimated, if the centuries-old traditional methods of biomass use are reconsidered and an efficient, rational use is implemented. The present pattern and share of biomass consumption of different traditional biomass energy devices are recorded. The efficiency of traditional technologies and that of improved ones—technologies which are practically applicable or already in use somewhere else—are compared and the potential of biomass savings is calculated. The total biomass saving potential in all seven countries together has been estimated at 322 million tons/year