{"title":"Human exposure to RF radiation in Sri Lanka","authors":"M. Karunarathna, I. J. Dayawana","doi":"10.4038/SLJP.V6I0.198","DOIUrl":"https://doi.org/10.4038/SLJP.V6I0.198","url":null,"abstract":"This paper presents the exposure levels of major cities in Sri Lanka due to the different RF emitters. As the RF emitters, the transmitting antennas of FM radio, TV and Cellular Mobile Base stations were considered. Field strength measurements were made at several locations in big cities and the exposure levels were obtained using a dipole antenna mounted 1.4m above the ground level to consider the exposure to RF radiation by the general public. The results were compared with the internationally recognized FCC standards and the present exposure levels were found to be well below the maximum limits set by the standards. The percentage distribution of electromagnetic field radiated from FM radio, TV and Cellular Mobile services for different environments are also presented. In addition, the unsafe distances to live from different transmitting antennas are presented.","PeriodicalId":21880,"journal":{"name":"Sri Lankan Journal of Physics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2005-12-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87140987","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}
M. Alam, M. Kabir, Ka Zaman, M. Rafiuddin, G. Ahmad
{"title":"Internal Dosimetry of Human Brain for 99m tc and 131 I Using Nuclear Imaging in Bangladesh","authors":"M. Alam, M. Kabir, Ka Zaman, M. Rafiuddin, G. Ahmad","doi":"10.4038/SLJP.V6I0.199","DOIUrl":"https://doi.org/10.4038/SLJP.V6I0.199","url":null,"abstract":"Internal dosimetry deals with the measurement of the radiation dose absorbed internally by an organ after the application of isotopes for diagnosis and treatment. In the present study radiation absorbed dose has been calculated for 99m Tc-pertechnetate, 99m Tc-DTPA, 99m Tc–hepatate and 131 I (NaI) which are used frequently for functioning test of disordered organs and therapeutic treatment of thyroid in Bangladesh. In these cases a small amount of isotopes are accumulated in other soft tissues like brain, gonads etc. Brain tissues are soft and cannot be regenerated if it is damaged. So, to ensure the safety of brain, the internal radiation absorbed dose has been calculated from direct measurement by using planer image of gamma cameras. International Commission for Radiological Protection (ICRP) and National Commission for Radiation Protection (NCRP) have laid emphasis on direct measurement because it provides more accurate result than that of other methods which are based on few mathematical assumption, bio-kinetic modeling and extrapolation of animal data to human etc. Finally these results have been compared with the data of ICRP publication 71.","PeriodicalId":21880,"journal":{"name":"Sri Lankan Journal of Physics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2005-12-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81020119","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}
{"title":"Redistribution of Energy in Electromagnetic Wave Interactions: Interference of electromagnetic waves; a different approach","authors":"C. Piyadasa","doi":"10.4038/sljp.v6i0.201","DOIUrl":"https://doi.org/10.4038/sljp.v6i0.201","url":null,"abstract":"One of the well-known effects of electromagnetic waves is interference. Redistribution of energy in interference is well documented in literature but the mechanism has not been discussed in detail. A set of new experiments has been designed and conducted to observe the actual redistribution of the energy of the electromagnetic waves while being interfered and after leaving the region of interference. In this paper, it is shown that the redistribution of energy in interference of electromagnetic waves maintains the energy distribution prevailed at the moment they leave the disturbance (interference) area. Modified wave fronts which separated after intersection of two coherent waves in microwave frequency is demonstrated. Results are presented in pictorial and graphical models in order to understand the phenomena,. Further experiments are underway and possible mechanism will be discussed later.","PeriodicalId":21880,"journal":{"name":"Sri Lankan Journal of Physics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2005-12-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78621828","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}
{"title":"Light Scattering Intensity and Viscosity Correlation for the Letters Printed on the Tobacco Cigarettes","authors":"P. Jayaweera, C. Pathiraja, R. Rajapaksha","doi":"10.4038/SLJP.V6I0.196","DOIUrl":"https://doi.org/10.4038/SLJP.V6I0.196","url":null,"abstract":"The quality of the letters printed on the tobacco cigarettes, brand name “John Player™” is found to be viscosity dependent on the ink used for printing. The viscosity changes of the ink used, cause the printed letters to be smudged and of poor quality. At present selection of bad quality prints are done by visual identification, as no scientific technique is available. We have developed a light scattering technique using a 632.8 nm 20 mW He-Ne laser system to correlate the scattering intensity with the viscosity of the ink used, LogoRed TC2582. As a result, a standard has been assigned and quality of the cigarette prints can be maintained during the manufacturing process.","PeriodicalId":21880,"journal":{"name":"Sri Lankan Journal of Physics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2005-12-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76667303","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}
{"title":"Synthesis of Triphenylamine Trisazo Dye and Study of its Uses in Dye Sensitized Solar Cells","authors":"G. Senadeera, K. Jiang","doi":"10.4038/SLJP.V6I0.200","DOIUrl":"https://doi.org/10.4038/SLJP.V6I0.200","url":null,"abstract":"A new triazo dye was synthesized from tri(p-aminophenyl)amine and 2 hydroxy-3-napthoic acid and explored the possibilities of its uses in dye sensitized solar cells for the first time. The photocells were able to generate reasonably high photocurrent in the presence of the electron donating ionic liquids in the electrolyte composed of redox couple I3 /I . Cells fabricated by sensitizing TiO2 generated a short-circuit photocurrent of ~ 3.5 mA cm -2 , an open-circuit photovoltage of ~ 500 mV with a total power conversion efficiency of ~ 1 % under simulated full sunlight of 100 mW cm -2 (Air Mass 1.5).","PeriodicalId":21880,"journal":{"name":"Sri Lankan Journal of Physics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2005-12-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88202991","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}
{"title":"Employing NiO as a hole collector in solid-state dye-sensitized solar cell","authors":"J. Bandara, H. Weerasinghe","doi":"10.4038/SLJP.V5I0.193","DOIUrl":"https://doi.org/10.4038/SLJP.V5I0.193","url":null,"abstract":"","PeriodicalId":21880,"journal":{"name":"Sri Lankan Journal of Physics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2004-12-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85951189","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}
{"title":"Efficient solid-state dye sensitized solar cells fabricated on a compact Ti) 2 barrier layer preventing short-circuit current","authors":"J. Bandara, H. Weerasinghe","doi":"10.4038/SLJP.V5I0.195","DOIUrl":"https://doi.org/10.4038/SLJP.V5I0.195","url":null,"abstract":"","PeriodicalId":21880,"journal":{"name":"Sri Lankan Journal of Physics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2004-12-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91327697","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}
{"title":"Semi classical chaos in a 2-D exactly solvable system","authors":"A. Nanayakkara","doi":"10.4038/SLJP.V5I0.192","DOIUrl":"https://doi.org/10.4038/SLJP.V5I0.192","url":null,"abstract":"","PeriodicalId":21880,"journal":{"name":"Sri Lankan Journal of Physics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2004-12-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81265166","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}
{"title":"Electric field penetration effects in time-of-flight measurements","authors":"Uk Abeywarna, T. Ariyaratne","doi":"10.4038/SLJP.V4I0.191","DOIUrl":"https://doi.org/10.4038/SLJP.V4I0.191","url":null,"abstract":"The field imperfections in the mass spectrometers were studied by means of two Plasma desorption time-of-flight mass spectrometers. The experiment was performed by investigating the influence of the field leakage due to the post acceleration on the measured values of the initial axial energy of secondary ions, in the presence of the grounded grids, which are usually employed to separate the fields inside the mass spectrometers. It has been found that the changes of 0.4% in the effective lengths of the acceleration gap and the field free region respectively are possible due to the field penetration into those regions from the post acceleration gap of the mass spectrometer. The analyses also show clearly the significance of the influence of the field penetration of the post acceleration on the measured values of the initial axial energy. The initial axial energies of H*, Hj , Li, ^Li , Na + and Cs + measured under the minimum field penetration condition were found to be 4.7 eV, 4.7 eV, 0.6 eV, 0.7 eV, 0.7 eV and 1.3 eV respectively, and they had been reduced to 4.4 eV, 4.4 eV, 0.3 eV, 0.4 eV, 0.4 eV and 1.0 eV once the values were corrected separately for field penetration. These results indicate that the field penetration through a grid is a secondary effect and it is hardly unavoidable in the mass spectrometers.","PeriodicalId":21880,"journal":{"name":"Sri Lankan Journal of Physics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2003-12-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74691124","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}