1,721,026 research outputs found
Reply to 'gamma radiation measurement'
Get PDFOn page 441, Ramli et al make a statement that the Ludlum micro-R meter has an almost flat response to gamma radiation. I think this is unlikely, as the instrument is basically a simple sodium iodide scintillator based ratemeter with a fixed energy threshold. Such instruments generally have a response which varies considerably over the range of interest for environmental dosimetry. This ranges from the highest significant energy generated, 2.615 MeV from Tl-208, down to the lowest energy which is likely to escape from bulk material as a consequence of Compton scatter, around 60 keV. As an example, the response of a 38 mm × 55 mm sodium iodide detector varies over a range of 10 from Co-60 (1.25 MeV) to 109 keV when used in the gross count mode. The range varies by a factor of 2 between Co-60 and Cs-137 (662 keV), which are reasonably close to K-40 at 1.46 MeV and the 609 keV line from Bi-214, both of which are, or can be, major contributors to environmental gamma dose rates. This is with a much bigger detector than the one employed by the authors. Moving to a smaller detector, such as the 25.4 mm × 19 mm one in the Thermo 41 detector, the energy response varies by a factor of 30 from 87 keV to 1.25 MeV, with a Cs-137/Co-60 ratio also of 2. The detector in the instrument used is likely to have a range of response somewhere between the two
Study on high radiation area, Palong, Segamat
Get PDFPengukuran kadar dos sinar gama daratan, terrestrial gamma radiation dose-rate (TGRD) di alam sekitar telah dilakukan di negeri Johor. Dari data yang diperolehi hubungan di antara latarbelakang geologi dan jenis tanah dengan aras TGRD telah dianalisis secara statistik menggunakan kaedah analisis varians sehala, one way analysis of variance, ANOVA. Semasa penyiasatan kawasan sinaran latarbelakang tabi’I tinggi telah ditemui di Palong, daerah segamat, Johor. Kajian radiology telah dilakukan untuk menetukan aras TGRD dan dos kepada penduduk di kawasan tersebut. Rangkaian kepekatan uranium-238 dan torium-232 dalam sample tanah, air, rumput rampai, lumut dan buah kelapa sawit telah dilaksanakan untuk menetukan kemungkinan radiologi yang ada
Natural terrestrial gamma radiation dose rate and its radiation risk to the public in the high background area surrounding Kampung Sungai Durian, Perak,Malaysia
No full textGamma rays (also called gamma radiation), are penetrating electromagnetic radiation of a kind arising from the radioactive decay of atomic nuclei. It consists of photons in the highest observed range of photon energy
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Selection of possible candidate area for nuclear power plant in Johor, Malaysia
Get PDFNuclear power is considered as one of the best option for future energy development in Malaysia. Since Malaysia has no experience in nuclear energy generation, commissioning the first nuclear power plant needs tremendous effort in various aspects. Site selection is one of important step in nuclear power plant commissioning process. This paper proposes candidate sites for nuclear power plant in Mersing, Kota Tinggi, Muar and Batu Pahat district in Johor, Malaysia. The candidate selection process uses the IAEA document and AELB guideline as main reference, supported by site selection procedure by various countries. MapInfo Professional software was used to simulate the selection process for candidate areas for the nuclear power plant. This paper concluded that Tenggaroh and Jemaluang area are the most suitable area for nuclear power plant facilities in Johor, Malaysia
The world's high background natural radiation areas (HBNRAs) revisited: A broad overview of the dosimetric, epidemiological and radiobiological issues
No full textThe residents of the world's high background natural radiation areas (HBNRAs), such as Ramsar (in Iran), Guarapari (in Brazil), Orissa and Kerala (in India) and Yangjiang (in China) have lived in these areas for generations under extraordinary radiation fields. The failure of earlier epidemiological studies to report any substantial increase in cancer incidence in HBNRAs has raised some controversy regarding the validity of the linear no-threshold hypothesis. This paper reviews some of the most recent studies of HBNRAs with the intent of stimulating greater research interest in the dosimetric, epidemiological and radiobiological issues related to the world's HBNRAs and proposes solutions to the challenges facing HBNRA studies. This paper may serve as a useful reference for some of the harder-to-find literature
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Terrestrial gamma radiation dose study to determine the baseline for environmental radiological health practices in Melaka state, Malaysia
No full textEnvironmental terrestrial gamma radiation dose rates were measured throughout Melaka, Malaysia, over a period of two years, with the objective of establishing baseline data on the background radiation level. Results obtained are shown in tabular, graphic and cartographic form. The values of terrestrial gamma radiation dose rate vary significantly over different soil types and for different underlying geological characteristics present in the study area. The values ranged from 54 ± 5 to 378 ± 38 nGy h-1. The highest terrestrial gamma dose rates were measured over soil types of granitic origin and in areas with underlying geological characteristics of an acid intrusive (undifferentiated) type. An isodose map of terrestrial gamma dose rate in Melaka was drawn by using the GIS application 'Arc View'. This was based on data collected using a NaI(Tl) scintillation detector survey meter. The measurements were taken at 542 locations. Three small 'hot spots' were found where the dose rates were more than 350 nGy h-1. The mean dose rates in the main population areas in the mukims (parishes) of Bukit Katil, Sungai Udang, Batu Berendam, Bukit Baru and Bandar Melaka were 154 ± 15, 161 ± 16, 160 ± 16, 175 ± 18 and 176 ± 18 nGy h -1, respectively. The population-weighted mean dose rate throughout Melaka state is 172 ± 17 nGy h-1. This is lower than the geographical mean dose rate of 183 ± 54 nGy h-1. The lower value arises from the fact that most of the population lives in the central area of the state where the lithology is dominated by sedimentary rocks consisting of shale, mudstone, phyllite, slate, hornfels, sandstone and schist of Devonian origin which have lower associated dose rates. The mean annual effective dose to the population from outdoor terrestrial gamma radiation was estimated to be 0.21 mSv. This value is higher than the world average of 0.07 mSv
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
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