Browsing by Author "Watugala, GK"

Now showing 1 - 10 of 10

item: Conference-Abstract
Design, fabrication and testing of a thermo-electric refrigeration unit
(2008) Fernando, SVA; Wijesekara, RGRP; Wijewardane, MA; Watugala, GK; Attalage, RA
A Thermo-Electric Refrigeration Unit to be used as a portable vaccine cooler in rural areas, where the main grid supply is unavailable was designed and constructed. Thermo-Electric modules working on the Peltier Effect, which causes to generate hot and cold sources when a current passes through dissimilar semiconductor materials, have been employed. The cold source is used to cool the refrigerating environment within its cabin and heat of the hot source is evacuated to the surrounding environment. The designed refrigerator is smaller in size and light in weight. The input power to the refrigerator is around 90 W. Minimum designed temperature is 15 oc less than the ambient temperature which is suitable for vaccine preservation. The cooling volume of the refrigerator is 18 liters.
item: SRC-Report
Enhancement of output of solar panels by means of reflectors
Watugala, GK; Attalage, RA
The energy supply from the sun is truly enormous: on average, the earth’s surface receives about 1.2*1017W of solar power. This means that less than one hour enough energy is supplied to the earth to satisfy the entire energy demand of the human population over the whole year. Indeed, it the energy of sunlight assimilated by biological organisms over millions of years that has made possible the industrial growth as we know. Most of the other renewable means of power generation also depend on the sun as the primary source: hydroelectric, wind and wave power all have the same origin. Solar cells did not have to wait long to find application. The year 1958 witnessed the launch of Vanguard 1, the first satellite to use electricity from the sun. The technology has been developing ever since. Much interest in solar electricity appeared particularly in the wake of the oil crisis in the early seventies. Today, the direct conversion of light into electricity, or photovoltaic, is becoming accepted as an important form of power generation.
item: Article-Full-text
Generation of Sinhala characters in autocad drawings
Watugala, GK; Janaka Mangala, KH
More and more industries in Sri Lanka are now turning to computers to make engineering drawings. The most popular software package for computer aided drawing (CAD) is AutoCAD developed by AutoDESK Inc. of USA. The computer-Aided Design and Computer Aided Manufacturing (CAD/CAM) centre of the Department of Mechanical Engineering obtained the AutoCAD package as early as 1991. CAD/CAM Centre has so far trained over 300 personnel in industry on the use of AutoCAD by running weekend short courses.
item: Article-Full-text
Generation of Sinhala characters in autocad drawings
Watugala, GK
More and more industries in Sri Lanka are now turning to computers to make engineering drawings. The most popular software package for computer aided drawing (CAD) is AutoCAD developed by AutoDESK Inc. of USA. computer-Aided Design and Computer Aided Manufacturing (CAD/CAM) centre of the Department of Mechanical Engineering obtained the AutoCAD package as early as 1991. CAD/CAM Centre has so far trained over 300 personnel in industry on the use of AutoCAD by running weekend short courses.
item: Conference-Extended-Abstract
High-precision thickness measurement using a laser-based optical method
(2002) Watugala, GK; Damgampola, PS; Priyanka, MTD; Wickramanayaka, DRK; Wickramasinghe, PDOJS
In metal rolling and in calendaring operations, the raw material is squeezed through two horizontal cylindrical rollers rotating in opposite directions. The thickness of the sheet coming out of the two rollers must be kept within a certain tolerance so that the sheet can go to the next stage in the production process.
item: Thesis-Abstract
Low cost one axis solar tracking operated by water pressure
(3/28/2011) Jayampathy, KAM; Watugala, GK
The scope of this study is to design a simple & low cost solar tracking system, which make uses downward movement of a piston cause by controlled discharge of water from water filled cylinder. The solar panels are mounted on the lever and when the lever rotates, the panels also rotate by the same angle, which is required. Rotation is done by connecting two pistons to the frame of panel via two links. In the method describe here. PV panel is mounted on a frame that pivot on an axis running from South to north with a slight inclination towards the north. As the sun moves from the morning to afternoon, the PV panel is rotated around the axis to make it normal to the Sun's rays as far as possible. The rotation is not done continuously since it will drain some of the solar energy collected with great difficulty. Instead, the rotation is done intermittently./ The tracking is activated by the controlled discharge of water from water filled cylinder. When water is discharged by a controlled rate, the piston on top of water column moves down. The downward motion of piston is then converted to a rotary motion of the frame around the pivot axis by means of two links. The discharge of water is controlled by an electronic circuit, which gets signals from two sensors mounted on the lever. There is an opaque screen normal to the PV panel and between the light sensors. When the incident solar rays are normal to the lever, the two sensor readings arc equal. When it is not so. The difference of the two signals from the sensors is fed to an electronic circuit which opens the discharge valve of the water cylinder causing the piston to go dow n and rotate the frame w ith solar panel. When the solar panel is rotated in the correct direction by the required amount, the sensors generate the same readings and the electronic circuit stops the water discharge./ Test on this tracking system shows that the total power output of the solar panel can be increase by about 25 % on a sunny day. On a cloud} day . because of the diffused radiation the tracking is not that much advantage, and this is true for other tracking systems as well. It is expected that this low cost one axis tracking system would pave the w ay for future research to increase of solar energy output in a sunny day by employing reflectors fixed to the frame and rotating together.
item: Conference-Extended-Abstract
Low-cost one-axis solar tracking operated by water pressure
(2006) Jayampathy, M; Watugala, GK
Solar photovoltaic CPV)panels are increasingly used in rural areas of Sri Lanka where the main grid electricity is not available. The high initial cost is a major deterrent in the popularization of this renewable energy source. Because of the complexities and additional cost involved, solar tracking is not done for these panels, and the panels are mounted at a fixed orientation, normally at an inclination of about 6-10°, facing the South. The additional solar power obtainable by having one-axis solar tracking can not justify the additional cost needed for tracking mechanisms available now.
item: Conference-Abstract
Measurement of ocean wave height using a capacitance-based liquid level sensor
(1998) Watugala, GK; Dilhara, WA; Perera, NGDI; Ariyathilake, KKKC; Perera, SCR
A digital liquid level measuring gauge has been designed, constructed and laboratory tested. The prototype gauge is specially made for ocean wave height measurement, but the underlined principle can be extended to level measurements in other situations. The gauge consists of a field unit anchored at the location where the ocean wave height is to be measured, and a base unit stationed in land.. The base unit can be connected to a computer to download wave height data for analysis. The field unit (see Fig.) consists of (1) an air-filled torus-shaped fully submerged platform anchored to sea bed, (2) a level sensing column hinged to the platform, and (3) a control box with electronic circuits, a radio transmitter, and rechargeable batteries. The anchoring is done in such a way that the mean sea level is roughly at the centre of the level sensing column. The sensing columns should be longer than twice the amplitude of sea waves. The control circuits perform many tasks: it converts the variation of capacitance between the two vertical tubes in the sensing column to variable frequency radio signal; it determines the sampling periods and sampling rates; it also communicates with the base unit by radio signals. The field unit is designed to consume very little power and the rechargeable batteries alone can power the unit for 10 days. The base unit consists of a radio receiver, control circuits, and an interface. This unit can receive radio signals from the field unit which must be within 2 km. It decodes radio signals and obtains digital wave height data for transmission to a computer using the parallel port.
item: Thesis-Abstract
Operation of two – axis solar tracking by the discharge of water from a tank hanging by a non - circular sprocket wheel
(2014-07-14) Indika, MHS; Watugala, GK; Wimalasiri, WK
Two-axis solar tracking system operated by the discharge of water from a bottom hole of a tank filled with water was designed, constructed and tested. The water tank is hanged by a chain passing over a non-circular sprocket wheel which is fixed to the rotating shaft along the first solar tracking axis. A counterweight is also hanged by another chain passing over a regular circular sprocket. In the morning, the tank is full and the water tank and the counterweight on either side of the shaft balance in such a way that the solar panel is facing the East as required. This study shows that the contour of the non-circular sprocket wheel can be designed taking into consideration the reduction of weight of water tank with time and the required rotation for solar tracking. In addition to the hourly tracking by the above mechanism, provision has been made to tilt the second tracking axis of the solar panel manually on a weekly basis to compensate for the seasonal variation of the Sun's declination. Results show that the additional cost involved in making this mechanism is justifiable when considering the increase of about 30% of more solar power obtainable by two-axis tracking. The paper published regarding this tracking system at Sri Lanka Association for the Advancement of Science (SLAAS) in 64th Annual Sessions held on 01-06 December 2008 shown in Appendix A.
item: Conference-Full-text
Optical character recognition for sinhala text using feature analysis
(1999) Watugala, GK; Kumara, WMP
Optical Character Recognition (OCR) is now a reality for documents printed in English. In the present study, the groundwork for the recognition of Sinhala characters is done. Matrix Matching and Feature Analysis are the two commonly used methods for the recognition of English letters. In this study the Feature Analysis method is investigated to recognize Sinhala characters. Matrix matching method is found to be suitable for recognizing documents containing text with known font and typeface. It should also be used to identify and extract the modifiers used on top, down or after the character. This helps in the identification of the base character using feature analysis. Several features of Sinhala characters can be extracted by running simple programs on the pixel array of the character. These features include aspect ratio, inscribing octagon, and number of pixel curves crossed when the character is sliced at different angles. By running these programs on Sinhala characters one can prepare a set of values of these features for standard characters. Afterwards the features of an unknown character can be compared with the standard data for recognition. Programming for Sinhala Character Recognition is done using MathCAD, an application package for complex mathematical calculations. Since the algorithms are written in pseudocode it is easy to convert these algorithms to a C++ program.