ERU - 1995
Permanent URI for this collectionhttp://192.248.9.226/handle/123/19483
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- item: Conference-Full-textProceedings of Symposium on Industry Related Research 1995 - Pre Text(Engineering Research Unit, Faculty of Engiennring, University of Moratuwa, 1995-03) Dias, WPS
- item: Conference-Full-textArtificial neural networks for construction bid decisions(Engineering Research Unit, Faculty of Engiennring, University of Moratuwa, 1995-03) Dias, WPS; Weerasinghe, RLD; Dias, WPSAn Artificial Neural Network (ANN) approach was explored for supporting construction bid decisions, since such decisions are heavily dependent on practitioner expertise, which in turn is generally encapsulated in case histories. One of the ANNs described here was trained on knowledge from a sample of the entire Sri Lankan construction industry, and was used to predict the preferred job sizes for firms of differing characteristics; such information could help firms in their bid/no-bid decisions. The other ANN was trained on case histories elicited from a single contractor, and was used to predict the percentage mark-up. The network outputs were obtained in both binary output and continuous valued output formats. The former format had some distinct advantages over the latter, as it provided greater information for decision making instead of being a "black box" output. The influences of the middle layer size, output format and allowable error during training, on the training duration and accuracy of prediction were studied.
- item: Conference-Full-textRenewable energy based water lifting devices - hydraulic ram pumps(Engineering Research Unit, Faculty of Engiennring, University of Moratuwa, 1995-03) Dias, WPSHydraulic ram pumps are powered by the energy of falling water. They have minimal impact on the environment. Ram pumps can be useful in small scale rural water supply and irrigation particularly in hilly areas. These can be manufactured locally and there is a growing interest in the use of ram pumps. The promotion of technological awareness and local manufacture within the proper social context, would be key factors if ram pumps are to find widespread use in Sri Lanka. The article also focuses on some of the work being done in this field at the University of Moratuwa. There is considerable potential for University - Industry co-operation in promoting the appropriate use of ram pumps, which can benefit rural communities.
- item: Conference-Full-textUse of precast prestressed concrete beams in continuous bridge construction(Engineering Research Unit, Faculty of Engiennring, University of Moratuwa, 1995-03) Weerasekara, IRA; Jayasinghe, MTR; Dias, WPSUse of precast prestressed concrete beams is a common practice in Sri Lanka. The main advantages being factory production of beams, ease of erection and speed of construction. However there are inherent problems associated in these bridges when multi-spans are adopted. This is because expansion joints over each pier gives rise to problems such as deterioration, maintenance and performance. In coastal roads there are added problems of deterioration. A solution to these problems is the introduction of continuity over piers. However, continuity itself will have a few problems at the design stage which have to be carefully tackled. The problems are design complications arising due to differential creep and shrinkage, thermal movement and the behaviour of the beams over the pier at ultimate limit state. There are four continuity methods currently used in other parts of the world. Out of these, the most suitable type for Sri Lanka has to be selected by considering ease of construction and durability. When continuity is introduced, it is important to ensure that the existing standard sections can be used. The paper gives the details of analysis, design and also areas for further research.
- item: Conference-Full-textA nitriding technique for improving die life(Engineering Research Unit, Faculty of Engiennring, University of Moratuwa, 1995-03) Thilakawardana, D; Tittagala, SR; Dias, WPSThe absence of proper understanding and facilities for heat treatment, specifically surface treatment techniques has retarded the development of tooi and die industry in Sri Lanka. Thus there has been a growing interest among the local tool manufacturers and users for new heat treatment techniques. It has been shown that the surface properties for Dies and Moulds can be enhanced by nitriding and this technique was first used in early 1920’s. Since then much development has taken place and now the technique can be applied to a greater variety' of steels than it was originally thought possible. However nitriding is still in its infancy as far as the local industry is concerned. Nitriding is basically the introduction of atomic nitrogen from a surrounding medium into the surface of steel by diffusion. In contrast to most heat treatment procedures nitriding changes both the chemical composition and the structure of the layer thereby enabling the properties to vary in a wider range. Extreme hardness, retention of hardness at elevated temperatures, improved fatigue strength and corrosion resistance are some of the properties imparted by nitriding. This paper describes the work carried out towards developing a suitable nitriding technique adaptable by the local medium and small scale industries with due regards to economy and safety aspects. It is expected to carry out industrial trials to assess the efficiency of the proposed setup.
- item: Conference-Full-textBiomethanation studies at university of moratuwa(Engineering Research Unit, Faculty of Engiennring, University of Moratuwa, 1995-03) sivapathasundaram, R; Wanigasekara, N; De Alwis, AAP; Dias, WPSBiogas generation or Biomethanation offers a viable option in simultaneous solid waste management and energy generation. The technology is quite well developed and is not only confined to developing countries as commonly perceived by many. However, the scale of practice and the objectives in developing and developed countries vary. A biogas program has been active in Sri Lanka as well, though this has not achieved the popularity or acceptance as in countries like China, India and Nepal. The Sri Lankan program however, has been successful in giving rise to a new design which is termed the Dry Batch digester. The work has been mainly done by the National Engineering Research and Design Centre (NERD). The concept is different to the two main types due to the use of an essentially ‘dry* mixture of organic waste, and the batch type operation. In urban areas biomass such as straw or animal wastes such as cowdung cannot be found in such quantities to have biogas systems of continuous nature. The NERD version of batch type could be effectively employed in institutions where organic wastes are generated, or to employ solid wastes such as market garbage. Their biomethanation kinetics favour the batch approach. The objective of the research program undertaken by the Department of Chemical Engineering was to do detailed evaluation of scientific, technological and social aspects of biogas systems as a means of pollution prevention with simultaneous energy generation. Laboratory studies have been done on various industrial waste streams ranging from food processing wastes to textile industry effluents which arc quite toxic to micro-organisms in general. This paper introduces the basic concepts and some of the methodologies followed by the research team. To support dissemination of biogas technology, a pictorial step-bystep guide detailing out all stages involved in the building and operation of a digester and a gas holder system has been prepared as part of this work.
- item: Conference-Full-textOhmic heating for tropical food processing : f experimental studies on heating and nutrition effects.(Engineering Research Unit, Faculty of Engiennring, University of Moratuwa, 1995-03) Shantha, W; De Alwis, AAP; Edirisinghe, R; Dias, WPSOhmic heating of foods is a novel food processing operation which directly utilizes electricity as the major heat source, and can be termed as an electroheat technique. The heat effect is achieved by passing an electric current through the product to be heated, the passage of current through the material obeys Ohm's law and depending upon the resistance offered by the media, heat is generated. If the objective is only heat generation, it matters little whether DC or AC is used, however, the use of AC can eliminate electrolysis. Electrolysis of food is obviously undesirable and so ohmic heaters are operated using an AC supply. Little work has been carried out with regard to this process and that it is only recently research has been started in UK, USA and France. Ohmic heating offers several important advantages over conventional food processing. It is possible to apply the technique to process many types of food materials. Some of these are beverage, dairy and vegetable products etc. Results of studies conducted on heating profiles and nutrient retention are presented. Initially a detailed picture of current fruits and vegetable production and associated problems are presented as this provides the essential back drop to this study. Basic nutrition studies have revealed some new information. Nutrition studies conducted has been for the first time and is of major importance.
- item: Conference-Full-textProcessing aids for rubber compounding(Engineering Research Unit, Faculty of Engiennring, University of Moratuwa, 1995-03) Gunapala, PY; Adikary, SU; Dharmawardena, G; Dias, WPSThis paper reviews some aspects of rubber-filler interaction in the presence of resins. Laboratory investigations conducted by us with optical methods, power traces. DTA , DSC curyes and treatment of samples with various solvents and tests for physico-mechanical properties were used to demonstrate specificity in behaviour of selected resins and to discuss a concept which could explain mechanism of reinforcement in the presence of various resins, intimate analysis has snown capability of certain resin to promote wetting properties and give high true contact between iubber and carbon black particles, thereby best owing favourable physicc-mechanical properties to the compound. Information of this type can assist not only the compounders bat also can give theoretical explanation about additional reinforcement in the presence of selected resins.
- item: Conference-AbstractMulti-criteria measurement and decision model(Engineering Research Unit, Faculty of Engiennring, University of Moratuwa, 1995-03) Sun, PYT; Dias, WPS