Sri Lankan Journal of Physics
Permanent URI for this collectionhttps://dl.nsf.gov.lk/handle/1/8218
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Item A Cyclic Voltammetry study of a gel polymer electrolyte based redox-capacitor(Institute of Physics:Colombo, 2015) Bandaranayake, C.M.; Weerasinghe, W.A.D.S.S.; Vidanapathirana, K.P.; Perera, K.S.Item A model for thundercloud charge separation(Institute of Physics:Colombo, 2012) Tennakone, K.; Hewageegana, P.Item A quantitative approach to gemstone identification using Raman spectroscopy combined with machine learning(Institute of Physics:Colombo, 2022) Boteju, W.I.W.Y; Gunarathna, M.K.A.S.; Fonseka, T.L.M.D; Peiris, H.N.S.; Silva, L.A.R.; Jayathilaka, N.N.S.S.; Jayasekara, L.A.G.D.; Perera, P.N.; Jayaweera, H.H.E.; Gunewardene, M.S.; Jayawardhana, S.Raman spectroscopy is an ideal technique for gemstones identification due to its nondestructive nature, rapid detection, no sample preparation, and ability to analyze interior compositions. Notwithstanding the benefits, most routine gemstone analysis requires complementary techniques to verify the accuracy due to difficulties in matching Raman spectra against a known database, while ensuring high sensitivity, specificity, and accuracy. This work presents a technique where computational methods are used to accurately identify gemstones for routine operations. The acquired Raman spectroscopic data is preprocessed using baseline subtraction and signal smoothing for optimal signal extraction and then cross correlated with a verified database of spectra. The correlation coefficient results are then clustered using a K-means algorithm to distinguish the gemstone families. The locally sourced unknown gemstone was found to belong to the quartz family with a sensitivity of 100%, specificity of 98% and accuracy of 98%. A second technique was also introduced by considering both cross correlation and overlap between the area under the curves of matched spectra. Both methods converged on the same conclusion and was backed up by three common cluster validation indices thereby assuring the validity of the identification. The technique was further validated to be used with other gemstone families such as beryl, diamond, and corundum.Item A theoretical investigation of nonrelativistic bound state solution at finite temperature using the sum of modified Cornell plus inverse quadratic potential(Institute of Physics:Colombo, 2020) Maireche, A.; Ikot, A.N.Item Activity of cloud-to-ground lightning observed in Sri Lanka and in surrounding area of the Indian Ocean(Institute of Physics. Colombo, 2001) Weerasekera, A.B.; Sonnadara, D.U.J.; Fernando, I.M.K.; Liyanage, J.P.; Lelwala, R.; Ariyaratne, T.R.Item Adaptation of a technique to estimate rainfall from satellite data in Bangladesh(Institute of Physics. Colombo, 2003) Islam, M.N.; Wahid, C.M.M.Item Applicability of natural rubber based polymer electrolyte for electrochemical double layer capacitors(Institute of Physics:Colombo, 2019) Sanjaya, N.A.A.K.; Perera, K.S.; Vidanapathirana, K.P.Item Application of mass spectrometry to characterize the components present in a curcumin sample(Institute of Physics. Colombo, 2003) Coorey, R.V.; Hakansson, P.Item Appraisal of mechanical properties of different particle sizes of palm kernel shell, coconut shell and mixed palm kernel-coconut shells particles epoxy-filled composites(Institute of Physics:Colombo, 2020) Alabi, A.B.; Salawu, M.A.; Jimoh, R.A.; Akomolafe, T.; Oluwayemi, M.Item Approximate Analytical Solutions of the Effective Mass Klein-Gordon Equation for Two Interacting Potentials(Institute of Physics:Colombo, 2018) Ebomwonyi, O.; Onate, A.C.; Onyeaju, M.C.; Okoro, J.; Oluwayemi, M.Item Approximate energy expressions for confining polynomial potentials(Institute of Physics:Colombo, 2002) Nanayakkara, A.; Bandara, V.Item Approximate l-States Solutions to the Schrodinger Equation with Manning-Rosen plus Hellmann Potential via WKB Approximation Scheme(Institute of Physics:Colombo, 2018) Benedict, I.I.; Louis, H.; Nelson, N.I.; Lkeuba, A.; Ozioma, A.U.; Thomas, M.O.; Pigweh, A.I.; Michael, M.O.Item Artificial muscles based on Polyacrylonitrile based polymer electrolyte(2007) Perera, K.; Vidanapathirana, K.P.; Dissanayake, M.A.K.L.Item Bound state solutions of the Klein - Gordon equation for deformed Hulthen potential with position dependent mass(Institute of Physics:Colombo, 2012) Antia, A.D.; Ikot, A.N.; Ituen, E.E.; Akpan, I.O.Item Bound states of two dyons and two fermions(Institute of Physics. Colombo, 2000) Pant, P.C.; Pandey, V.P.; Rajput, B.S.Item Calculation of Feynman diagrams using a symbolic manipulation programme in personal computers(Institute of Physics. Colombo, 2000) Dharmaratna, W.G.D.; Karunarathna, M.A.A.Item Capacitive and Bioenzymevoltaic Characteristics of Photosynthetic Chromolena Odorata – Nanostructured Zinc Oxide System(Institute of Physics:Colombo, 2016) Obasuyi, A.R.; Alabi, A.B.; Kajewole, E.D.; Robert, O.; Abejide, F.; Adeleke, T.J.; Akomolafe, T.Item Characterization of electrochemically prepared CuSCN films and their capabilities of application in dye sensitized photovoltaic cells(2008) Sirimanne, P.M.; Zhang, J.B.Item Comparison of RegCM3 simulated meteorological parameters in Bangladesh: Part I-preliminary result for rainfall(2007) Rahman, Md.M.; Islam, Md.N.; Ahmed, A.U.; Afroz, R.Item Comparison of RegCM3 simulated meteorological parameters in Bangladesh: Part II-preliminary result for temperature(2007) Rahman, Md.M.; Islam, Md.N.; Ahmed, A.U.; Afroz, R.