Browsing by Author "Fernando, MARV"

Now showing 1 - 20 of 31

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Analysis and design of garbage compacting tractor trailer for Sri Lanka
(2008) Wanigasinghe, N; Wijesinghe, A; Fernando, MARV; Piyasiri, TA
Low efficiency in collection and transportation of garbage and environmental pollution with the currently available vehicles such as open dump trucks, tractor trailers are two of the main problems encountered in solid waste management in Sri Lanka. This paper proposes an innovative design using a currently available tractor trailer improve above problems. The capacity of waste transported is improved by compacting the garbage using a hydraulic system. A closed body is built with safe unloading system to overcome the environmental pollution.
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An analysis of pelton turbines as related to mini-micro hydro applications
(2000) Fernando, MARV
Large Pelton turbines used in major hydro applications are of high efficiency, in the range of 92% or more. However, Peltons used in mini-hydro applications in Sri Lanka were often found to be of lower efficiency, and of micro range much lower. The main factors affecting efficiency are identified as per available literature and analytically discussed.. Effect of nozzle efficiency, bucket friction, speed ratio and bucket geometry are further analyzed as per a novel theoretical derivation. These are compared with available practical data and experience. The results are discussed with a view to improve the efficiency of mini/micro range of Pelton turbines and recommendations made accordingly.
item: Thesis-Abstract
The Analysis of suitable frame (structure) for a pedal car
(3/28/2011) Molligoda, MLCY; Fernando, MARV
This study is mainly focused on to determine a suitable structure for the pedal car by considering following areas. 1.To determine the number of wheels for the pedal car/ 2.Driven drive (whether front or rear) 3.Number of wheels for steering "Tadpole car" is the final designed of the research because it is comparatively easy to fabricate and, there are so many advantages when fixing power transmission and steering mechanisms./ Here the steering mechanism couples with front wheels of the "tadpole" structure. It governs by standard bicycle handle. End of the handle, by using two steel rods, couples with pin joint to the front wheels. Suspensions arc necessary to maintain comfort-ability of the car. Therefore front wheels are assembled with two springs. And Rear wheel later part was assembled with pin joint and upper joint introduced with coil spring. This combination helps to maintain Constancy distance between flywheel and the rear wheel./ Brake must be with the vehicle to safe operation of it. Here all three wheels are controlled at the same time by jamming one liver. It is important for the stability of the vehicle while stopping. Steel Conduits are used for the fabrication of first embodiment. But after Cosmos analysis, it reveals that maximum stress occurred on the structure is 27 N/mm2. For Cosmos analysis, numbers of possible load combinations were applied on seat and paddles. Seat load considered as distributed load and pedal load took as point load/ Further this research can turn to another area of "law weight structures". Herein maximum efficiency can be achieved by reducing the body weight of the car. And it will help to popularize the car. Because generally riders like easy- handling vehicles. This goal would be achieved by replacing steel parts with Aluminum alloy or Timber/Structures wherever possible.
item: Thesis-Full-text
Analysis of the possibility of minimising the warpage in injection moulding
Premarathna, GAR; Fernando, MARV
This thesis focuses on the research “to investigate and analyse the warpage in a product and reduce the warpage using optimum parameters”. Factors affecting for warpage are discussed and categorized their relative position of affecting. An article subjected to warpage is selected and factors affected for the warpage are detailed analysed one by one. The research carried out on the basis of selected major factors. Part geometry, gate location, runner system, filling and packing/ holding pressures, filling and packing/ holding times and cooling layout are analysed and changed to determine optimum parameters and minimize the warpage factor. Modified mould design was done by utilizing Computer Aided Design and analysed the mould to ensure the success of the design. The CAD Software used for design is Unigraphics NX and two software packages used for analysis of warpage are Auto Desk Moldflow Advisor and Solid Works Plastics. Finally with the justification of changed parameters the existing mould is modified to meet the required quality of product. In this context, all above details are comprehensively discussed and summarized in the body of this report accompanied by necessary drawings, data tables and analysis results etc.
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Application of ergonomic principles in designing of human powered vehicle - the "pedal car"
(2006) Shereefdeen, Z; Fernando, MARV
Transportation is one of the key issues currently we face in Sri Lanka. Situation has become more complex with soaring fuel price. Further, petroleum fuel powered vehicles cause enormous environmental problems particularly in urban areas. A recent research has revealed that over 60% of all vehicles plying Sri Lankan roads are within the borders of the Colombo Metropolitan Region (CMR). Approximately 75% of the pollutants released to the air originate from the transport sector. On the other hand, being a poor nation having a per capita income of less than U$ 1200per annum, automobile is a luxury for the average person. Therefore use of Human Powered Vehicles (HPV) for day to day transportation becomes worth investigation and promotion.
item: Conference-Full-text
Chemical treatment of timber, a novel method
(2000) Fernando, MARV
Dwindling resources of quality timber made manufacturers to look for alternatives. Species such as Rubber -"Hevea brasiliensis" were found to be good alternatives once treated against "Borer" attack. While expensive "Vacuum-Pressure Impregnation" provides total impregnation, cheaper methods such as "Dip" or "Spray" provides only a superficial treatment which may be removed during steps involved in furniture manufacture and similar processes. Analysis of "Mechanism of Impregnation in Vacuum-Pressure Process" indicate several short comings in the common explanation available. A new hypothesis suggested was verified with experimentation. Based on this explanation a "Novel Method", which uses simple equipment, yet ensuring total and perfect impregnation, though at a slightly lower rate, was developed. In this process the timber, immediately after sawing, is stacked in a tank (or a pit) to which the chemical solution pumped to completely submerge the timber. After the lapse of a specified period of time solution is pumped to a similar tank located adjoining (or close by) which too has a similar load of timber. While one tank is tilled with chemical solution air is blown through the timber stacks of the dry tank. A spray of steam, if available, will be advantageous. While laboratory tests have proved the efficiency of the process field tests have proved the consistency of the process and durability of treated items. Cost analysis shows that the novel process is a very economical alternative, particularly attractive to Medium and Small Scale Industries.
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Comparative analysis of milling of copper and graphite electrodes for EDM and identifying machine capabilities
(2014-05-29) De Silva, KCJ; Fernando, MARV
Copper and graphite are the two mostly used materials in Electrical Discharge Machining electrodes in injection mould making. This work is done in collaboration with a local company and a foreign tool maker. Though several research papers found on comparative analysis of copper and graphite milling, they are not applicable to the selected foreign tool maker, since the machines used are different and it is totally applications-driven and so much depends on what has to be done on the shop floor in the way of support equipment. In this work, a tool is developed to be used on the shop floor for a collaborated work done by a local company and a foreign tool maker for the comparative analysis of milling of copper and graphite electrodes for EDM. Machine capabilities of copper and graphite milling are analyzed by experimental methods with the optimum parameters set in the machines. Material removal rate for rough milling and surface finishing rate for fine milling are found to be indicators of machine capabilities. An experienced tool maker can provide the necessary inputs to calculate the cost and time of producing electrodes, leads to a proper comparison of EDM electrode milling in economical terms rather than a guess, which is the current practice. With the use of the calculator the costs and time of producing electrodes are analyzed and recommendations made based on the data available with EDM machines in general. The cost calculator improved by EDM analysis is to be integrated with the existing costing system of the company. Also the flexibility is provided in the cost calculator to change the values fed in the calculator, so that it can be customized for the use of any other tool shop. Keywords: sinking EDM, graphite and copper electrodes, machine capabilities, CNC milling, cost calculator.
item: Conference-Abstract
Critical analysis of banki turbine
(2006) Fernando, MARV
'Banki turbine', named after its inventor professor Banki, is different from other types in that the flow through the turbine is across it. Thus some literature prefers to call it 'crossflow turbine', while some others try to name it after 'Osberger' who too seems to have developed the same concept independently, though well after Prof Banki who holds the patent for this invention.
item: Thesis-Abstract
Critical evaluation of container trailer failures and improvements in their manufacture
(2014-08-06) Mugunthan, S; Fernando, MARV
Container trailer manufacturing is a growing industry in Sri Lanka. Only two organizations are involved in this business and the monthly production was recorded as 100 to 125 trailers. Like other manufacturing industries, trailer industry also faces problems due to trailer failures and difficulties to improve the trade. Failures are mainly due to lack of design stage analysis of the product. The primary objective of my research project is to analyze trailer failure problems and suggest solutions to improve the trailer industry in Sri Lanka. The methodology of this research is a combination of research training programme, questionnaire based study and a finite element analysis of the trailer solid model. Research training programme was arranged in a leading manufacturing and servicing organization in Sri Lanka by the Department of Mechanical Engineering, University of Moratuwa. It was very useful to understand the trailer manufacturing concepts, designs, trailer failures and the general problems faced by the trailer industry. Questionnaires are produced to two different categories of industries such as Trailer manufacturers and Trailer users. Questionnaires for trailer manufacturers are oriented towards identifying the techniques used by manufacturers to control the failures especially in design stage and identifying their problems and limitations in manufacturing trailers. Questionnaires for trailer users are oriented towards identifying trailer failures. A finite element analysis was carried out to study the present design of a particular type of trailer to identify the efficiency in design and to present any solutions if needed. Further, there were several rounds of semi-structured interviews with technical specialists, designers, supervisors and welders who were involved in trailer manufacturing. By the combination of all the efforts, it is found that trailer failures are mainly due to the problems due to design, fabrication, materials and parts selection, human resource and trailer misuse. Suggestions to present trailer problems and future improvements in trailer manufacture are produced.
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Critical evaluation of container trailer failures and improvements in their manufacture
(6/17/2011) Mugunthan, S; Fernando, MARV
Container trailer manufacturing is a growing industry in Sri Lanka. Only two organizations are involved in this business and the monthly production was recorded as100 to 125 trailers. Like other manufacturing industries, trailer industry also faces problems due to trailer failures and difficulties to improve the trade. Failures are mainly due to lack of design stage analysis of the product. The primary objective of my research project is to analyze trailer failure problems and suggest solutions to improve the trailer industry in Sri Lanka. The methodology of this research is a combination of research training programme ,questionnaire based study and a finite element analysis of the trailer solid model. Research training programme was arranged in a leading manufacturing and servicing organization in Sri Lanka by the Department of Mechanical Engineering, University of Moratuwa. It was very useful to understand the trailer manufacturing concepts, designs ,trailer failures and the general problems faced by the trailer industry. Questionnaires are produced to two different categories of industries such as Trailer manufacturers and Trailer users. Questionnaires for trailer manufacturers are oriented to wards identifying the techniques used by manufacturers to control the failurese specially in design stage and identifying their problems and limitations in manufacturing trailers. Questionnaires for trailer users are oriented towards identifying trailer failures. A finite element analysis was carried out to study the present design of a particular type of trailer to identify the efficiency in design and to present any solutions if needed. Further, there were several rounds of semi-structured interviews with technical specialists, designers, supervisors and welders who were involved in trailer manufacturing. By the combination of all the efforts, it is found that trailer failures are mainly due to the problems due to design, fabrication, materials and parts selection, human resource and trailer misuse. Suggestions to present trailer problems and future improvements in trailer manufacture are produced.
item: Conference-Extended-Abstract
Critical investigation of pumps as turbines(pat) for mini, micro and pico hydro applications
(2004) Fernando, MARV
Reverse running of standard centrifugal pumps as turbines (PAT), or more particularly pump-motor (PM) sets as turbine-generator (TO) sets had been advocated for some time, especially for mini/micro-hydro applications. This has the claimed main advantage of cost benefit of equipment.due to mass production of PM sets compared to turbines and/or generators, which are usually 'order made' or tailer made. Though some PM sets are reported to be in operation as TOs, even in Sri Lanka, their widespread use as initially anticipated has not been achieved. This is due to very low efficiency of such units observed under practical situations, which negates the cost advantage.
item: Conference-Extended-Abstract
Critical investigation of tongue and groove joint in wooden furniture design and manufacture in Sri Lanka
(2002) Fernando, MARV
Furniture manufacture during early days was a highly skilled craft where appearance and functions were innovatively designed, but the joints were done in the traditional manner. Though high quality timber was invariably used at that time, its scarcity has forced manufacturers to go for other varieties among which treated rubber is very common.
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Design and development of a machine for selective plucking of tea or similar items
(2006) Krishantha, RPP; Fernando, MARV
First stage of Tea manufacture is plucking. This may be done in two ways, "Pluck and select" OR "Select and pluck - called selective plucking". First method can use simple machines, such as grass trimmers even, and impurities such as stork, matured leaves etc are removed later. This method is suitable only for lower grades of tea and also causes damage to plant and reduces growth and yield. While first method is used in certain countries such a Kenya, Japan etc., Sri Lanka being the HIGHEST quality tea manufacturer in the world, invariably use "Selective plucking" due to its many advantages. However this at present is a completely manual process and is responsible for a substantial portion of the cost of tea manufacture. Problem is further aggravated by the pluckers leaving this job due to strenuous nature and the low social status attached to it. Plantation sector thus is now finding it very difficult to retain pluckers, particularly with younger generation, and payment rates are also continuously increasing.
item: Thesis-Abstract
Design of a garbage compacting tractor trailer hydraulic system
(7/22/2011) Wanigasinghe, N; Fernando, MARV
The most common motorized vehicle used for garbage transportation in Sri Lanka is the tractor with an open trailer. Garbage is transported in an open system causing unpleasantness, pollution, bad smell, poor hygiene and over spillage. The objective of the proposed design is to improve the capacity of garbage handled by the open tractor-trailer per each transport cycle and to improvise a closed system for waste transport to improve hygienic standards. The proposed design is one in which an existing tractor-trailer is modified to a rear loading trailer. While loading, the garbage will be compacted using a hydraulic system to overcome the low productivity. A hydraulic pump, solenoid valves, hydraulic cylinders and an electrical system are used for this construction. Apart from this, the trailer body is modified into a closed body. The measured value of solid waste currently handled per single load which is approximately 1000 kg, will be improved to about 2000 kg per load. The closed system will minimise the environmental pollution present in the existing system. These modifications to the existing tractor trailer would help to improve the present standards of , solid waste management at a relatively low cost. The cost of installation of the hydraulic system and constructing a closed body IS approximately seven hundred thousand rupees.
item: Conference-Abstract
Design of a human powered vehicle for urban environments - frame and body
(2006) Molligoda, MLCY; Fernando, MARV
The future of "green transport" is of great concern to rational planners and politicians who want to find solutions to the many environmental problems caused by the extreme popularity of the automobiles. Therefore, a research group met, studied and discussed the state of the art of human powered vehicles (HPVs).
item: Thesis-Abstract
Design of a power transmission system of a pedal car
(3/28/2011) Edirisinghe, A; Fernando, MARV
Transportation has become a major socio-economic and environmental problem in urban environments today. Escalation of oil prices, environmental pollution, unsafe conditions, unbalanced designs of bicycles, motorcycles, and three wheelers and complex lifestyle are some of those significant contributing factors to it. Ergonomically designed Human Powered transport is one of the feasible solutions for urban requirements. Ergonomics deals with human comfort in any work situation in order to operate it efficiently and effectively. Concept of pedal car came into being in order to eliminate discomfort and unsafe conditions due to heat, dust, rain, unbalanced designs, uncovered body, and fatigue due to uneasy- postures. In addition to the above it provides cheap transport and recreational facility, physical exercise, while providing additional value for the rider to iron out complex health hazards./ Design of Power transmission system integrates with Engineering aspects, strength, rigidity, stability and ergonomics aspects. One of the major innovative steps taken in fabrication of first embodiment of the pedal car is to eliminate long chains by introducing pedal linkage with a shorter chain. First embodiment incorporates positive achievements such as; ergonomically designed compact long wheel base and seat, shorter chain, standard parts, small wheel sizes. Affordable price, environmentally friendly, fashionable appearance, F.asy manufacturability and maintainability of Driving Mechanism, and physical exercise to the rider. Over weight of frame and wheel assembly deprived acceleration in gradient at 30° to Kim/h and 15-18Km/h in level roads. Reduction of weight of the first embodiment by rc-design and re-selection of parts with lighter hood cover with additional power supply to the system also required to overcome the above problem. One of the major limitations of this study is maximum human power in put. Further study on maximum power application in relation to pedal height, seat angle, toot position and crank length is also important for further improvements.
item: Thesis-Abstract
Design of selective tea plucking machine
(3/28/2011) Krishantha, RPP; Fernando, MARV
This thesis focuses on the research project is "Selective Tea Plucking Machine". /According to my literature survey I have found that Tea plucking machines are designed in many countries but they are designed only for plucking and selecting method. These machines are very large and expensive. It is used only for flat land. However this at present is a completely manual process and is responsible for a substantial portion of the cost of tea manufacture./ In manual plucking, plucking tea leaves are retained between fingers till reasonable amount of leaves are collected. Then 'holding between fingers' often cause some degree of crushing leading to commencement of premature fermentation. Therefore quality will be reduced. Thus it has become essential to mechanize this process to improve productivity, yet retaining the high quality and accuracy of selective plucking. Due to above technical and financial restrictions facing with research as well as depth of expected research study to be performed by using own methods to design low cost and portable machine. In this context is carried out considering selective plucking method. Further, considering the ergonomics aspects are essential for this design, it is useful to operate this machine without fatigue. It is based on less weight of the machine, holding and bag (container) arrangement. It is understood that the given detailed of the cutting mechanism and the tea leaves are transported to the bag (container) with suitable convey system. This report contains literature survey, field test, design details, and economic feasibilities.
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Effect of blade friction on performance of Micro-Hydro pelton turbines : mathematical modeling and experimental verification
(2015-02-08) Atthanayake, IU; Fernando, MARV; Sugathapala, AGT
Water turbines have been used in electricity generation for well over a century. Hydroelectricity now supplies 19% of world electricity and 44% (as at 2012) of Sri Lanka's electricity also comes from hydropower. Micro Hydro is a term used for hydroelectric power installations that typically produce up to 20 kW of power in Sri Lankan context. Many Micro-hydro power plants are operated with Pelton turbines. The main reasons for using Pelton turbines are that they are very simple and relatively cheap. As the stream flow varies, water flow to the turbine can be easily controlled by changing the number of nozzles or by using adjustable nozzles. Since most of the micro hydro Pelton turbines are now manufactured locally, it was revealed that much attention is not paid to the surface finish of the turbine buckets. On the other hand due to sand erosion of turbine parts bucket surface are getting rough day by day. Most of the research that had been done on turbines were focused on improving the performance with particular reference to turbine components such as shaft seals, speed increasers and bearings. There is not much information available on effects of blade/bucket friction on the performance of Pelton turbine. The main objective of this research is to analyze the performance of Micro hydro Pelton turbine particularly with respect to their blade friction. The governing laws of fluid dynamics, relevant to the application were used to develop a theoretical model to estimate the effect of blade friction on Pelton turbine performance. Then the developed mathematical model was validated experimentally. All the experiments are carried out in a Pelton turbine standard test bench. The power developed by the turbine was measured by keeping all the relevant parameters that affect to the power development, constant other than the friction of the bucket. The friction of the buckets was varied by varying surface roughness of the buckets. Different roughnesses of the surface was obtained by pasting various grades of sands one at a time on the surface of the buckets . It was concluded from the developed mathematical model and the experimental testing that power developed by a Pelton turbine increases when the surface roughness of the turbine bucket decreases. It was also proved from the research that splitter thickness of the buckets is also affect the power developed by the turbine. When the thickness of the splitter increases power developed by the turbine decreases. Therefore it is recommended from the study that Pelton turbine buckets must be smooth as much as possible and splitter of the buckets should be as sharp as much as possible to generate more power from a power plant.
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Effect of cryogenic cooling on machining performance on hard to cut metals - a literature review
(2013) Senevirathne, SWMAI; Fernando, MARV
This paper presents a literature review done on Cryogenic cooling, Liquid Nitrogen Cooling(LNC), and 'Chilled Air and Minimum Quantity Lubrication' (CAMQL) cooling methods used in machining operations, targeting to recognise better cooling methods for the Sri Lankan die and mould making sector (SLDMMS). The state of the art in cryogenic machining was searched and reviewed first, and then its benefits, limitations, and applications were studied. Alternative cooling methods for conventional emulsion cooling were searched. The benefits from cryogenic cooling and other alternative methods were analysed and compared. LNC and CAMQL cooling were chosen as subjects for further comparative study. A substantial amount of literature was found on the effect of these cooling methods on hard-to-cut materials such as lnconel, Titanium alloys etc., but very few or no studies had been carried out on materials used in the Sri Lankan die and mould making sector. A survey on materials used in SLDMMS is recommended to identify the most commonly used material types. An economic feasibility study of cryogenic cooling and chilled air cooling is recommended.
item: Conference-Full-text
Effect of cryogenic cooling on machining performance on hard to cut metals - a literature review
(The Engineering Research Unit, University of Moratuwa, 2013-02) Senevirathne, SWMAI; Fernando, MARV; Rodrigo, R
This paper presents a literature review done on Cryogenic cooling, Liquid Nitrogen Coot,ng(LNC) and •Chilled Air and Minimum Quantity Lubrication (CAMQL) cooling methods used ,n targeting to recognise belter cooling methods for the Sri Lankan d,e and mould making sector (SLDMMS). The state of the art in cryogenic machining was searched and reviewed first, and then its benefits, limitations and applications were studied. Alternative cooling methods for conventional emulsion cooling were seai ched. The benefits from cryogenic cooling and other alternative methods were analysed and compared. LNC and CAMQL cooling were chosen as subjects for further comparative study. A substantial amount of literature was found on the effect of these cooling methods on hard-to-cut materials such as Inconel, Titanium alloys etc., but very few or no studies had been carried out on materials used in the Sri Lankan die and mould making sector A survey on materials used in SLDMMS is recommended to identify the most commonly used material types. An economic feasibility study of cryogenic cooling and chilled air cooling is recommended.