PURSE 2003

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https://ir.lib.pdn.ac.lk/handle/20.500.14444/50

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    Effect of coconut fat on guinea pig serum lipid composition
    (The University of Peradeniya, 2003-10-23) Edirisinghe, E. M. I.; Fernando, P. H. P.; Perera, P. A. J.; Kappagoda, C. T.
    Epidemiological studies have shown that there is a highly significant correlation between the daily intake of saturated fat, serum cholesterol, and mortality from coronary heart disease. It has been demonstrated that of the fatty acids investigated, the most hypercholesterolemic was myristic (14:0), followed by palmitic (16:0), lauric (12:0) and stearic acids (18:0), respectively. Hence, nutritionists recommend the limiting of the proportion of energy derived from saturated fat, as a means of reducing the incidence of coronary atherosclerosis. The aim of this study was to find the effect of coconut fat ingestion on serum fatty acid composition, and it's relationship to serum cholesterol level, in an animal model. Three groups of male Hartley guinea pigs were fed ad lib. With isocaloric diets containing coconut oil, com oil, or coconut/ com oil (1:1) mixture added to the diet at 5 %( w/w). Test diets were prepared according to specific guinea pig requirements by Dyets Inc. Company, Pennsylvania USA. Test diets were fed for a period of 3 months and blood was collected by cardiac puncture after a 14-h fast. Serum cholesterol was analysed using enzymatic colorimetric method. Total fats in the serum were extracted, saponified, acidified and the fatty acids composition was analysed using gas chromatography method. Results were analysed using one-way ANOV A. Among the fatty acids analysed, myristic and palmitic acids levels in the fasting blood sera were significantly different (p<0.05) in the coconut oil consuming group compared to the other two groups. The highest levels of myristic and palmitic acids, 41.2 ± 9.8 and 22.4 ± 9.1 mg/dl, respectively, were recorded in the coconut oil group. In the com oil group, the values were 22.0 ± 7.5 and 11.1± 3.7 mg/dl respectively. In the group consuming coconut/com oil (1: 1) mixture, the values were 21.4 ± 11.2 and 11.9 ± 4.4 mg/dl respectively. However, there was no significant difference between the com oil and the coconut/com oil (1:1) mixture group. This shows that the cholesterolgenic fatty acid levels in fasting blood sera were significantly higher in the coconut oil consuming group. Serum cholesterol levels were significantly different (p
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    Diversity of mosses on some selected sites at Hantana range -a preliminary study
    (The University of Peradeniya, 2003-10-23) Jayawardana, J. K. M. B.; Abeyagoonasekera, R. M. K.; Wijetunga, A. S. T. B.
    Studies on bryophytes are very few and scanty; and further there are no active bryologists in Sri 'Lanka, The present study was planned to fill the gaps of knowledge on mosses of the island to a certain extent. A survey was done to study the diversity of mosses in some selected sites at Hantana range, from June to December 2002. Three main habitats (viz. forest patch, stream side and road side) and three microhabitats within each main habitat (viz. rock surface, tree trunk and soil surface) were selected to sample mosses. A total of 468 moss samples (stream side-295, forest patch-89 and road side-84) were collected during the survey. These belong to 16 families (33%) and 26 genera (15%) out of the 48 families and the 174 genera of mosses, which have been recorded from Sri Lanka to date. The results revealed a relatively high diversity and richness of mosses in the study area
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    Distributed control of permanet magnet drives systems via ethernet
    (The university of Peradeniya, 2003-10-23) Samaranayake, Lilantha; Alahakoon, Sanath
    The recent. advancements of permanent magnet (PM) materials, solid-state devices and microelectronics have contributed to new energy efficient, high performance electric drives that use modern PM synchronous motors. Not surprisingly, these motors are continuously receiving serious considerations for various applications such as traction, automotive, robotics, aerospace etc. In general, PM synchronous motors can be classified into the brushless d.c. (BLDC) motors and a.c. synchronous motors (PMSMs). These motors can be further grouped based on the rotor configurations as surface mounted, inset and interior permanent magnet type motors. In this study, surface-mounted brushless d.c. motors are used in the distributed control drive system operated via Ethernet Distributing the main system modules i.e., mainly the controller in the closed loop, widens the single location applications of PMSM to applications with motors located at different places but are operating towards a common goal. The gild wing position operation of an air craft, driving wheel speed control of electric vehicles with no mechanical links between wheels are some of such applications. Hence it is a common requirement in all distributed motor control applications to maintain the speed locked (synchronized) condition among each other under respective load torque variations. That is, if one or a few motors of such a system encounter torque disturbances, the corresponding changes in speeds have to be reflected to the rest of the motors in the group with a minimum synchronizing error. Operating many machines in parallel with local controllers always result in a complicated and expensive wiring system. It is also difficult for fault diagnosis and maintenance. This results in increased system down time. Hence the distributed architecture of system control is vital in this kind of synchronization applications. In contrast to the centralized control systems, in a distributed control system, a communication network (Ethernet in this case) is used to connect the sensor to controller and controller to actuator of each control loop. Usually communication through the Ethernet is time constrained and makes the analysis and controller design complicated. The reason for this is the invalidity of the ideal centralized assumptions such as synchronized sensor and/or controller signal availability, non-delayed sensing and actuation. Hence the challenge of making the system distributed via Ethernet is first to handle the timing problems in the communicating media. The speed synchronization of different drives in the system is another challenge. Both the problems are addressed in this paper with extensive emphasis on different controller strategies