Pub Date : 2021-12-28DOI: 10.4038/josuk.v14i2.8034
M. Udawatta, R. D. De Silva, D. D. De Silva
{"title":"Calcium ion adsorption of Leucaena leucocephala wood biochar activated with coconut vinegar","authors":"M. Udawatta, R. D. De Silva, D. D. De Silva","doi":"10.4038/josuk.v14i2.8034","DOIUrl":"https://doi.org/10.4038/josuk.v14i2.8034","url":null,"abstract":"","PeriodicalId":444777,"journal":{"name":"Journal of Science of the University of Kelaniya Sri Lanka","volume":"19 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-12-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121531582","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-11-03DOI: 10.4038/josuk.v14i2.8036
L. Usgodaarachchi, C. Thambiliyagodage
{"title":"Photocatalytic activity of GO/Fe3O4 fabricated by Sri Lankan graphite under visible light irradiation","authors":"L. Usgodaarachchi, C. Thambiliyagodage","doi":"10.4038/josuk.v14i2.8036","DOIUrl":"https://doi.org/10.4038/josuk.v14i2.8036","url":null,"abstract":"","PeriodicalId":444777,"journal":{"name":"Journal of Science of the University of Kelaniya Sri Lanka","volume":"82 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-11-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131480830","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-09-10DOI: 10.4038/josuk.v14i0.8033
P. Samarasekara, M. K. Abeyratne
The magnetic properties of ferromagnetic thin films with three spin layers were investigated for the first time using fourth-order perturbed Heisenberg Hamiltonian. Total magnetic energy was determined for ferromagnetic materials with simple cubic lattice. The simulation was carried out for Heisenberg Hamiltonian with different second-order magnetic anisotropy constants in different spin layers. The total magnetic energy periodically varies with spin-exchange interaction, azimuthal angle of spin and the secondorder magnetic anisotropy constant in each spin layer. The peaks along the axis of the angle are closely packed except in the 3-D plot of energy versus angle and second-order magnetic anisotropy constant of the middle spin layer. 2-D plots were perceived by rotating 3-D plots in MATLAB. According to the 3-D plot, the angle between magnetic easy and hard directions is 90 degrees. The minimum energy range was found in the 3-D plot of energy versus angle and the second order anisotropy constant of the middle spin layer. The samples with the minimum magnetic anisotropy energies have potential application in transformer cores, magnetic switching and magnetic amplifiers.
{"title":"Magnetic properties of ferromagnetic thin films with three spin layers as described by fourth-order perturbed Heisenberg Hamiltonian","authors":"P. Samarasekara, M. K. Abeyratne","doi":"10.4038/josuk.v14i0.8033","DOIUrl":"https://doi.org/10.4038/josuk.v14i0.8033","url":null,"abstract":"The magnetic properties of ferromagnetic thin films with three spin layers were investigated for the first time using fourth-order perturbed Heisenberg Hamiltonian. Total magnetic energy was determined for ferromagnetic materials with simple cubic lattice. The simulation was carried out for Heisenberg Hamiltonian with different second-order magnetic anisotropy constants in different spin layers. The total magnetic energy periodically varies with spin-exchange interaction, azimuthal angle of spin and the secondorder magnetic anisotropy constant in each spin layer. The peaks along the axis of the angle are closely packed except in the 3-D plot of energy versus angle and second-order magnetic anisotropy constant of the middle spin layer. 2-D plots were perceived by rotating 3-D plots in MATLAB. According to the 3-D plot, the angle between magnetic easy and hard directions is 90 degrees. The minimum energy range was found in the 3-D plot of energy versus angle and the second order anisotropy constant of the middle spin layer. The samples with the minimum magnetic anisotropy energies have potential application in transformer cores, magnetic switching and magnetic amplifiers.","PeriodicalId":444777,"journal":{"name":"Journal of Science of the University of Kelaniya Sri Lanka","volume":"32 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116536477","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-06-18DOI: 10.4038/josuk.v14i0.8031
Y. S. S. Ariyarathne, N. Jayatissa, D. M. Silva
In this empirical study, socioeconomic factors that can easily be extracted from families have been used to build a "home electricity usage prediction" model based on two variables, family monthly income and family size. Each of these factors was evaluated individually. Two machine learning models were built using those factors as features. Models are based on “Linear regression” and “Random Forest” algorithms. This study revealed that the socioeconomic factors such as family size and family income are very effective in domestic electricity usage prediction model building, where the end usages are not known. Furthermore, the random forest algorithm was found to be more effective for unseen data than the linear regression algorithm. The accuracy of the models can be further improved by adding more data into the both models.
{"title":"Domestic electricity usage estimation model using socio-economic factors","authors":"Y. S. S. Ariyarathne, N. Jayatissa, D. M. Silva","doi":"10.4038/josuk.v14i0.8031","DOIUrl":"https://doi.org/10.4038/josuk.v14i0.8031","url":null,"abstract":"In this empirical study, socioeconomic factors that can easily be extracted from families have been used to build a \"home electricity usage prediction\" model based on two variables, family monthly income and family size. Each of these factors was evaluated individually. Two machine learning models were built using those factors as features. Models are based on “Linear regression” and “Random Forest” algorithms. This study revealed that the socioeconomic factors such as family size and family income are very effective in domestic electricity usage prediction model building, where the end usages are not known. Furthermore, the random forest algorithm was found to be more effective for unseen data than the linear regression algorithm. The accuracy of the models can be further improved by adding more data into the both models.","PeriodicalId":444777,"journal":{"name":"Journal of Science of the University of Kelaniya Sri Lanka","volume":"38 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-06-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125292704","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-05-13DOI: 10.21203/RS.3.RS-498370/V1
L. D. Amarasinghe, P. Nadeeka
{"title":"Population dynamics and breeding preference of Aedes aegypti and Ae. albopictus attributing to dengue threat in Kelaniya medical officer of health area in Sri Lanka","authors":"L. D. Amarasinghe, P. Nadeeka","doi":"10.21203/RS.3.RS-498370/V1","DOIUrl":"https://doi.org/10.21203/RS.3.RS-498370/V1","url":null,"abstract":"","PeriodicalId":444777,"journal":{"name":"Journal of Science of the University of Kelaniya Sri Lanka","volume":"385 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-05-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134063914","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-07-20DOI: 10.4038/josuk.v13i0.8023
S. Mahagama, D.S.M. de Silva, S. Wimalasena
Selenium is considered as an essential micronutrient. The daily requirement of selenium is 55 µg. As a result, the World Health Organization (WHO) has drawn their attention to establish the micronutrient range of selenium, required by the human body. Report from China has shown that an ecological correlation exists with the selenium content in the soil and increased mortality due to cancer and cardiovascular diseases with light intake of selenium. This led to the interest in assessing the nutritional status of selenium. Rice is the staple food of Sri Lankans and studies on selenium content in rice grown in Sri Lanka have not been reported. The present study reports the selenium content in Bg 350 variety of rice and soil obtained from twelve districts (Gampaha, Colombo, Matara, Hambantota, Kegalle, Matale, Anuradhapura, Pollanaruwa, Kurunegalle, Puttalam, Ampara and Moneragalle), in Sri Lanka determined using Hydride Generation Atomic Absorption spectrometer (HGAAS). The results of the study showed that selenium content in rice and soil obtained from Gampaha and Colombo districts were very low and less than the detectable levels of the instrument (0.5 μg/kg). Except for rice and soil from Pollanaruwa district that had a very high selenium content in rice (61.2 μg/kg) and soil (69.8 μg/kg), the respective values from other districts were low [13.8 μg/kg (Kegalle) -6.3 μg/kg (Anuradhapura)] and [20.3 μg/kg (Matara) -9.5 μg/kg (Matale)].
{"title":"Selenium content in Bg 350 variety of rice consumed by Sri Lankans","authors":"S. Mahagama, D.S.M. de Silva, S. Wimalasena","doi":"10.4038/josuk.v13i0.8023","DOIUrl":"https://doi.org/10.4038/josuk.v13i0.8023","url":null,"abstract":"Selenium is considered as an essential micronutrient. The daily requirement of selenium is 55 µg. As a result, the World Health Organization (WHO) has drawn their attention to establish the micronutrient range of selenium, required by the human body. Report from China has shown that an ecological correlation exists with the selenium content in the soil and increased mortality due to cancer and cardiovascular diseases with light intake of selenium. This led to the interest in assessing the nutritional status of selenium. Rice is the staple food of Sri Lankans and studies on selenium content in rice grown in Sri Lanka have not been reported. The present study reports the selenium content in Bg 350 variety of rice and soil obtained from twelve districts (Gampaha, Colombo, Matara, Hambantota, Kegalle, Matale, Anuradhapura, Pollanaruwa, Kurunegalle, Puttalam, Ampara and Moneragalle), in Sri Lanka determined using Hydride Generation Atomic Absorption spectrometer (HGAAS). The results of the study showed that selenium content in rice and soil obtained from Gampaha and Colombo districts were very low and less than the detectable levels of the instrument (0.5 μg/kg). Except for rice and soil from Pollanaruwa district that had a very high selenium content in rice (61.2 μg/kg) and soil (69.8 μg/kg), the respective values from other districts were low [13.8 μg/kg (Kegalle) -6.3 μg/kg (Anuradhapura)] and [20.3 μg/kg (Matara) -9.5 μg/kg (Matale)].","PeriodicalId":444777,"journal":{"name":"Journal of Science of the University of Kelaniya Sri Lanka","volume":"257 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-07-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134091209","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-11-21DOI: 10.4038/josuk.v12i0.8016
W. P. Wasana, K. A. P. P. Kuruppuarachchi, P. N. Yapa, S. Hettiarachi
Pectobacterium carotovorum is the most common causative organism of bacterial soft rot which gives rise to great economic losses. It is important to implement disease control measures and management strategies on this bacterium in order to prevent further crop loss. Among the various management strategies, using the antibacterial nature of spices offer promising solutions to pesticidal hazards and also to increasing cost of plant protection operations. Although there are many reports on the antibacterial nature of spices on various pathogens, its effect on P. carotovorum is limited. Objectives of this study were to determine the antimicrobial activity of selected spices and then to ascertain the minimum inhibitory concentration (MIC) of aqueous and ethanolic extracts of those spices against P. carotovorum. Among the nine tested spices, four were active against P. caratovorum. As depicted by agar well diffusion assay, the highest inhibitory effect on P. carotovorum was shown by the aqueous and ethanol extracts of Allium sativum while the aqueous and ethanolic extracts of Cinnamomum verum gave the smallest zones of inhibition. Garcinia cowa and Tamarindus indica displayed moderate antibacterial activity. There was no significant difference (p>0.05) in inhibition zones between aqueous and ethanol extract of a particular spice. MIC of the spices, which inhibited the growth of P. carotovorum was 0.5 g/ml within the test range. Positive extracts can be used as a cost effective and eco-friendly preventive strategy to minimize the effects of P. carotovorum. Evaluation of the antibacterial activity of these extracts under field conditions is necessary before a cost-effective formulation is developed.
{"title":"Antimicrobial activity of selected spices against Pectobacterium carotovorum isolated from some vegetables in Sri Lanka","authors":"W. P. Wasana, K. A. P. P. Kuruppuarachchi, P. N. Yapa, S. Hettiarachi","doi":"10.4038/josuk.v12i0.8016","DOIUrl":"https://doi.org/10.4038/josuk.v12i0.8016","url":null,"abstract":"Pectobacterium carotovorum is the most common causative organism of bacterial soft rot which gives rise to great economic losses. It is important to implement disease control measures and management strategies on this bacterium in order to prevent further crop loss. Among the various management strategies, using the antibacterial nature of spices offer promising solutions to pesticidal hazards and also to increasing cost of plant protection operations. Although there are many reports on the antibacterial nature of spices on various pathogens, its effect on P. carotovorum is limited. Objectives of this study were to determine the antimicrobial activity of selected spices and then to ascertain the minimum inhibitory concentration (MIC) of aqueous and ethanolic extracts of those spices against P. carotovorum. Among the nine tested spices, four were active against P. caratovorum. As depicted by agar well diffusion assay, the highest inhibitory effect on P. carotovorum was shown by the aqueous and ethanol extracts of Allium sativum while the aqueous and ethanolic extracts of Cinnamomum verum gave the smallest zones of inhibition. Garcinia cowa and Tamarindus indica displayed moderate antibacterial activity. There was no significant difference (p>0.05) in inhibition zones between aqueous and ethanol extract of a particular spice. MIC of the spices, which inhibited the growth of P. carotovorum was 0.5 g/ml within the test range. Positive extracts can be used as a cost effective and eco-friendly preventive strategy to minimize the effects of P. carotovorum. Evaluation of the antibacterial activity of these extracts under field conditions is necessary before a cost-effective formulation is developed.","PeriodicalId":444777,"journal":{"name":"Journal of Science of the University of Kelaniya Sri Lanka","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-11-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129855474","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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