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Wyświetlanie 1-7 z 7
Tytuł:
Studies of colored varieties of Brazilian quartz produced by gamma radiation
Autorzy:
Enokihara, Cyro T.
Schultz-Güttler, Rainer A.
R. Rela, Paulo
Calvo, Wilson A. P.
Powiązania:
https://bibliotekanauki.pl/articles/971525.pdf
Data publikacji:
2013
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
gemstone treatment
quartz color enhancements
color centers
quartz gamma irradiation
Opis:
Quartz occurs in Brazil mainly in two geological environments, called pegmatitic and hydrothermal. The quartz of hydrothermal origin occurs mainly in geodes in the basaltic rocks of the Parana Basin and the quartz formed in fracture systems of the Espinhaço Range. Quartz of pegmatitic origin forms often the core of pegmatites. The detailed mechanism of color center formation of these two types of quartz will be investigated by spectroscopic and chemical analysis. Until yet, it can be shown that due to chemical differences of the nature of mineral forming fluids, the two types behave differently. All quartz contains mainly traces of iron, aluminum, lithium and some amounts of water. The quartz of hydrothermal origin incorporated much structurally bound water, and despite some similarities with the chemical composition of pegmatitic quartz, this high water content is the reason for the formation of silanol radicals, giving green color to the quartz. The main difference in chemical composition of pegmatitic quartz is the presence of higher amounts of Al and Li, responsible for the brownish and yellowish colors formed by irradiation.
Źródło:
Nukleonika; 2013, 58, 4; 469-474
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Remediation of polluted waters and wastewater by radiation processing
Autorzy:
Sampa, M. H. O.
Takács, E.
Gehringer, P.
Rela, P. R.
Ramirez, T.
Amro, H.
Trojanowicz, M.
Botelho, M. L.
Han, B.
Solpan, D.
Cooper, W. J.
Emmi, S. S.
Wojnárovits, L.
Powiązania:
https://bibliotekanauki.pl/articles/147644.pdf
Data publikacji:
2007
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
electron beam
wastewater treatment
pesticides
dyes
degradation
radiation technology
Opis:
Application of radiation processing for drinking water, wastewater, and groundwater treatment is a cost effective process which may insure adequate availability of that resource worldwide. This paper summarizes the results of a Coordinated Research Project (organized by the IAEA) with participants from 10 countries with the purpose of describing the degradation mechanism of organic impurities, and establishing optimal treatment conditions. Decoloration, disinfection, microbiological and toxicological experiments are also mentioned. These experiments led to pilot plants and also to a large scale industrial realization of radiation technology.
Źródło:
Nukleonika; 2007, 52, 4; 137-144
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Recent studies of irradiated mangoes in Brazil : a trend towards commercial approach
Autorzy:
Sabato, S. F.
Silva, J. M.
Cruz, J. N.
Broisler, P. O.
Rela, P. R.
Salmieri, S.
Lacroix, M.
Powiązania:
https://bibliotekanauki.pl/articles/148822.pdf
Data publikacji:
2008
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
gamma radiation
mangoes
physicochemical properties
sensory evaluation
Opis:
Mango is an important commodity to our country as Brazil is a great producer and exporter of tropical fruits. Nowadays, Mexico and India are the main exporters of mango in the world and Brazil occupies the third position in this ranking. As these countries have adopted gamma radiation as a phytosanitary treatment and signed a bilateral agreement with the United States for exporting mango to this country, Brazil has to be up-to-dated with this trend. The Institute of Nuclear and Energy Researches together with field producers in the northeastern region and partners like the International Atomic Energy Agency, the Canadian Irradiation Center and Empresa Brasileira de Agropecuária joined to demonstrate this technology, its application and its commercial feasibility. The whole project was structured in two parts that involved around 1300 mangoes. The first step consisted mainly in studying the quality of irradiated mangoes within our territory, using a multipurpose semi-commercial cobalt facility, and comparing two harvesting points of the fruits. The second one was an international consignment of irradiated fruits from Brazil to Canada, where the control sample consisted of fruits treated with a hot water dip. The financial part of the feasibility study covers the scope of the investment, including the net working capital and production costs. In a summarized way to express, the results from physicochemical analysis and sensory evaluation were favorable, indicating that gamma radiation is a potential quarantine treatment.
Źródło:
Nukleonika; 2008, 53, suppl. 2; 77-79
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Leakage test evaluation used for qualification of iodine-125 seeds sealing
Autorzy:
Feher, A.
Rostelato, M. E. C. M.
Zeituni, C. A.
Calvo, W. A. P.
Somessari, S. L.
Moura, J. A.
Moura, E. S.
Souza, C. D.
Rela, P. R.
Powiązania:
https://bibliotekanauki.pl/articles/147662.pdf
Data publikacji:
2011
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
leakage test
iodine-125 seeds
prostate cancer
brachytherapy
titanium tube
standard ISO-9978
Opis:
Brachytherapy is one of the possible treatments with ionizing radiation available for prostate cancer, in which small seeds containing iodine-125 radioisotope are implanted directly into the prostate. The seed consists of a sealed titanium tube containing a central silver wire with adsorbed iodine-125. The tube sealing is made with titanium at the ends, using plasma arc-welding (PAW) or laser process. This sealing must be leakage-resistant and free of cracks, therefore avoiding iodine-125 to deposit in the silver wire to escape and spread into the human body. To ensure that this problem is not occurring, rigorous leakage tests in accordance with the standard ISO-9978 should be applied. The aim of this study is to determine, implement and evaluate the leakage test to be used in the iodine-125 seeds production, in order to qualify the sealing procedure. The standard ISO-9978 presents a list of tests to be carried out according to the type of source. The preferential methods for brachytherapy sources are soaking and helium. To assess the seeds leakage, the method of immersion test at room temperature was applied. The seeds are considered leakage-free if the detected activity does not exceed 185 Bq (5 nCi). An iodine standard was prepared and its value determined in a sodium iodide detector. A liquid scintillation counter was calibrated with the standard for seed leakage tests. Forty-eight seeds were plasma arc-welded for these tests.
Źródło:
Nukleonika; 2011, 56, 4; 375-379
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Gamma-ray computed tomography SCANNERS for applications in multiphase system COLUMNs
Autorzy:
Calvo, W. A. P.
Hamada, M. M.
Sprenger, F. E.
Vasquez, P. A. S.
Rela, P. R.
Martins, J. F. T.
de Matos Pereira, J. C. S.
Omi, N.
de Mesquita, C. H.
Powiązania:
https://bibliotekanauki.pl/articles/148082.pdf
Data publikacji:
2009
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
industrial computed tomography
multiphase flow systems
non-destructive testing
gas absorption column
industrial process optimization
packed distillation columns
scanning systems
Opis:
Gamma-ray tomography experiments have been carried out to detect spatial patterns in the porosity, in a 0.27 m diameter packed steel column using a first generation computed tomography (CT) system. The CT scanner consists of a NaI(Tl) detector 5.08 cm in diameter, and an encapsulated 137Cs (3.7 GBq) radioactive source, located opposite to the center of the detector. The detector and the source, mounted on a fixed support and the column, can rotated and dislocate by two stepping motors controlled through a microprocessor. Different sizes of stainless steel Raschig rings (12.6, 37.9 and 76 mm) have been examined. The primary objective of this work is to detect spatial patterns and statistical information on porosity variation in packed distillation columns. Horizontal scans, at different vertical positions of the packed bed were made for each size of Raschig rings. Radial porosity variation within the packed bed has been determined. This study has demonstrated that the porosity and its spatial distribution in a metallic packed column can be measured with adequate spatial resolution using the gamma-ray tomography technique. After validation of this first generation CT, the turntable design to rotate and dislocate the 60Co or 137Cs sealed gamma-ray sources and multidetector array for the third generation industrial computed tomography was also developed.
Źródło:
Nukleonika; 2009, 54, 2; 129-133
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Development of an irradiation system for a small size continuous run multipurpose gamma irradiator
Autorzy:
Calvo, W. A. P.
Rela, P. R.
Napolitano, C. M.
Kodama, Y.
Omi, N. M.
da Costa, F.
de Andrade e Silva, L. G.
Powiązania:
https://bibliotekanauki.pl/articles/148041.pdf
Data publikacji:
2009
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
multipurpose irradiator
gamma irradiator
compact irradiator
cobalt-60 irradiator
gamma facility
Opis:
The Radiation Technology Center from IPEN-CNEN/SP, Brazil, developed a revolutionary design and national technology, a small-sized continuous run and multipurpose industrial gamma irradiator, to be used as a demonstration facility for manufacturers and contract service companies, which need economical and logistical in-house irradiation system alternatives. Also, to be useful for supporting the local scientific community on development of products and process using gamma radiation, assisting the traditional and potential users on process validation, training and qualification of operators and radioprotection officers. The developed technology for this facility consists of a continuous tote box transport system, comprising a single concrete vault, where the automated transport system of products inside and outside of the irradiator utilizes a rotating door, integrated with the shielding, avoiding the traditional maze configuration. Covering 76 m2 of floor area, the irradiator design is a product overlap sources and the maximum capacity of cobalt-60 wet sources is 37 PBq. The performed qualification program of this multipurpose irradiator was based on AAMI/ISO 11137 standard, which recommends the inclusion of the following elements: installation and process qualification. The initial load of the multipurpose irradiator was 3.4 PBq with 13 cobalt-60 sources model C-188, supplied by MDS Nordion – Canada. For irradiator dose optimization, the source distribution was done using the software Cadgamma developed by IPEN-CNEN/SP. The polymethylmetacrylate (PMMA) dosimeter system, certified by the International Dose Assurance Service (IDAS) of the International Atomic Energy Agency (IAEA) was used for irradiator dose mapping. The economic analysis, performance concerning with dose uniformity and cobalt-60 utilization efficiency were calculated and compared with other commercial gamma irradiators available on the market.
Źródło:
Nukleonika; 2009, 54, 2; 93-97
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Development and production of radioactive sources used for cancer treatment in Brazil
Autorzy:
Rostelato, M. E. C. M.
Rela, P. R.
Zeituni, C. A.
Feher, A.
Manzoli, J. E.
Moura, J. A.
Moura, E. S.
Silva, C. P. G.
Powiązania:
https://bibliotekanauki.pl/articles/148305.pdf
Data publikacji:
2008
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
radioactive sources production
iodine-125 seeds
iridium-192 wires
brachytherapy
cancer treatment
Opis:
The number of cancer patients in Brazil is increasing and part of the patients are submitted to brachytherapy treatment using iridium-192 wire and iodine-125 radioactive seeds. The Nuclear Energy Research Institute established a programme to produce iridium-192 wire and iodine-125 radioactive seeds. With the purpose of settling a laboratory for iridium-192 sources production, a wire activation method was developed and a hot cell for the wire manipulation, quality assurance and packaging was built. The iodine-125 seeds consist of a welded titanium capsule containing iodine-125 adsorbed onto a silver rod. Concerning the setup of the local production, the following activities were carried out: superficial treatment of the silver rod, development of a process to absorb the iodine in the silver rod, welding methodology to seal the seeds, leakage and contamination test and source activity measurement.
Źródło:
Nukleonika; 2008, 53, suppl. 2; 99-103
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-7 z 7

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