Volume 03 - 2007
Permanent URI for this collectionhttp://repository.kln.ac.lk/handle/123456789/13900
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Item Investigation of anisotropy constants dependence of ultra-thin ferromagnetic films with second order perturbed Heisenberg Hamiltonian(University of Kelaniya, 2007) Samarasekara, P.The variation of energy of ferromagnetic ultra-thin films with second and fourth order anisotropy was investigated using Heisenberg Hamiltonian with second order perturbation. The study was limited to sc(001) film with three layers. Graphs indicate energy minimums at certain values of second order anisotropy, fourth order anisotropy and angle. Films with fourth order anisotropy ω )4( Dm =4 can be easily oriented in the direction given by angle of 2.66 radians for the values of other energy terms used in this simulation. When the second order anisotropy ( ω )2( Dm ) is 3.1, preferred direction is 0.754 radians. When the second order anisotropy varies at a constant value of fourth order anisotropy, the graph indicates more energy minimums.Item Studies on antioxidant activity of Indian gooseberry fruit and seed(University of Kelaniya, 2007) Nadheesha, M.K.F.; Bamunuarachchi, A.; Edirisinghe, E.M.R.K.B.M.; Weerasinghe, W.M.S.K.Fruits and seeds of Indian Gooseberry (Phylanthus emblica, S. Nelli) were investigated to evaluate their antioxidant activity. Antioxidant activity was evaluated by the estimation of peroxide values (PV) of shark liver oil, treated with fruit and seed extracts incubated at 600 C for a period of nine days. Seed extracts showed higher antioxidant activity than fruit extracts. The ethanol and ethyl acetate extracts of the fruit and all extracts of the seed were found to have higher antioxidant activity than the synthetic antioxidant butylated hydroxy toluene (BHT).Item New Interpretation Of Primitive Pythagorean Triples And A Conjecture Related To Fermat’s Last Theorem(University of Kelaniya, 2007) Piyadasa, R.A.D.; Munasinghe, J.; Mallawa Arachchi, D.K.; Kumara, K.H.In this study primitive Pythagorean triples have been carefully examined and found that all of them satisfy a simple rule related to mean value theorem. It is pointed out that integral triples satisfying the equation on Fermat’s Last Theorem should satisfy a special rule related to mean value theorem. A conjecture is proposed which may lead to find a simple proof of Fermat’s Last Theorem.Item Practical Issues in the Development of TTS and SR For The Sinhala Language(University of Kelaniya, 2007) Wickramasinghe, R.I.P.; Kumara, K. H.; Dias, N.G.J.In this study, discussed some issues that are arising in the development of Text-to-Speech (TTS) and Speech Recognition (SR) systems for the Sinhala language are discussed. There are numerous benefits of TTS and SR to Sinhala community. In the context of Sinhala language, the Natural Language Processing (NLP) technologies are in the primary stage in comparison with other languages such as English, French, German, Japanese etc. Since current TTS and SR development environments are far from being language independent, the existing systems cannot be adopted directly to the Sinhala language. This contribution outlines problematic areas that come across in the development of TTS and SR systems for Sinhala language. While discussing those problems, some of the possible solution strategies for both TTS and SR development have been formulated.Item Automatic Segmentation Of Given Set Of Sinhala Text Into Syllables For Speech Synthesis(University of Kelaniya, 2007) Kumara, K.H.; Dias, N.G.J.; Sirisena, H.A dictionary based automatic syllabification tool has been given for Speech Synthesis in Sinhala language. This tool is also capable of providing frequency distributions of Vowels, Consonants and Syllables for a given set of Sinhala text. A method of determining syllable boundaries has also been shown. Detection of Syllable boundaries for a given Sinhala sentence is achieved by four main phases and those phases have been described with examples. Rules for the automatic segmentation of words into syllables have been derived based on a dictionary. An algorithm has been produced for the implementation of these rules which utilizes the dictionary together with an accurate mark up of the syllable boundaries.Item Determination of Protonation Constants for 2-Hydroxy-1-(2-Hydroxy-4-Sulpho-1-Naphthylazo)-3-Naphthoic Acid(University of Kelaniya, 2007) Liyanage, J.A.; Janaratne, T.K.Chemical speciation modelling in combination with potentiometric titration method was used to determine the protonation constants for 2-hydroxy-1-(2-hydroxy-4-sulpho-1-naphthylazo)-3-naphthoic acid, the Patton and Reeder’s reagent, at 25° C in three ionic strengths of 0.1 mol dm-3, 0.01 mol dm-3 and 0.001 mol dm-3 NaNO3. Potentiometric titrations were performed and pH, titrant volume, temperature and free and total proton concentrations at each titration point were measured. Constants were determined for three of the four protonated sites and the forth one being a very low value as this site is always in the ionic form and is readily ionized in aqueous solutionsItem Methyl Transferase, a Polyketide Biosynthetic Enzyme from Dreschlera Monoceras: Purification and Properties(University of Kelaniya, 2007) Weerasooriya, M.K.B.; Crosby, J.Methyl transferase, a polyketide biosynthetic enzyme in monocerin biosynthesis was isolated and purified from Dreschlera monoceras. The enzyme was purified to near homogeneity with 11.1% recovery, using ammonium sulphate fractionation followed by ultra filtration, SP Sepharose chromatography and gel filtration chromatography. The molecular mass of the purified enzyme as determined by elution through Superdex TM gel filtration chromatography was found to ~ 165kDa. SDS-PAGE of the purified enzyme showed a single band at ~55kDa indicating that possibly enzyme could be a trimer of 3 subunits. The enzyme showed optimum pH at 7.5-7.7, whereas optimum assay temperature was 35-37°C. Enzyme was stable up to 45°C and above this temperature enzyme activity slowly declined and inactivated around 70°C. Apparent Km of the enzyme was found to be ~ 0.083mM.Item Study on approaches to integrated control of Meloidogyne graminicola in rice(Journal of Science of the University of Kelaniya Sri Lanka, 2007) Amarasinghe, L.D.; Kariyapperuma, K.A.D.P.S.; Pathirana, H.N.I.Item Evaluationion of immune responses in an Indian carp, Labeorohita (Hamilton) fed with levamisole incorporated diet(Journal of the Science of the University of Kelaniya, 2007) Wijendra, G.D.N.P.; Pathiratne, A.