Navegação por ano de publicação "2017"

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  • IPEN-DOC 24165

    BARROSO, ALINE G. ; GARCIA, RAFAEL H.L. ; DEL MASTRO, NELIDA L. . X-ray diffraction pattern and relative crystallinity of irradiated arrowroot starch. In: INTERNATIONAL NUCLEAR ATLANTIC CONFERENCE, October 22-27, 2017, Belo Horizonte, MG. Proceedings... Rio de Janeiro, RJ: Associação Brasileira de Energia Nuclear, 2017.

    Abstract: After cereals, tubers and roots are the major source of starch for food and industrial uses. Arrowroot refers to any plant of the genus Marantha, but the term is most commonly used to describe the easily digested starch obtained from the rhizomes of Marantha arundinacae. The rhizomes of this herbaceous plant contain about 20% of starch. As few studies exist on arrowroot starch, the objective of this preliminary work was to study the X-ray diffraction patterns (XRD) patterns of arrowroot starch when treated by γ-radiation with doses up to 15 kGy in a 60Co source. The XRD patterns of the arrowroot starch exhibited A-type crystalline arrangements with strong peaks at approximately 15º, 17º, 18º and 23º (2θ). A slight increase of diffractogram peaks intensity was noticed after the irradiation process. The cristallinity index was calculated using Bruker DIFFRAC.EVA version 4.2 software. Relative crystallinity seems to increase with radiation doses, and this effect is more noticeable at low doses. That can be attributed to different radiation sensitivity among the amorphous and crystalline regions of the arrowroot starch molecule. Present results will contribute to elucidate the behavior under radiation treatment of this starchy component increasingly employed by the food industry.

    Palavras-Chave: cobalt 60; crystal structure; gamma radiation; irradiation; peaks; radiation doses; radiation effects; roots; starch

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  • IPEN-DOC 24174

    ICHIKAWA, RODRIGO U. ; LINHARES, HORACIO M.S.M.D.; SILVA, ANDRE S.B. da ; TEIXEIRA, MARIA I. ; RANIERI, IZILDA M. ; TURRILLAS, XAVIER; MARTINEZ, LUIS G. . X-ray diffraction analysis of KY3F10 nanoparticles doped with Nd and preliminary studies for its use in high-dose radiation dosimetry. In: INTERNATIONAL NUCLEAR ATLANTIC CONFERENCE, October 22-27, 2017, Belo Horizonte, MG. Proceedings... Rio de Janeiro, RJ: Associação Brasileira de Energia Nuclear, 2017.

    Abstract: In this work, the structure and microstructure of Nd:KY3F10 nanoparticles was probed using X-ray synchrotron diffraction analysis. Rietveld refinement was applied to obtain cell parameters, atomic positions and atomic displacement factors to be compared with the ones found in literature. X-ray line profile methods were applied to determine mean crystallite size and crystallite size distribution. Thermoluminescent (TL) emission curves were measured for different radiation doses, from 0.10kGy up to 10.0kGy. Dose-response curves were obtained by area integration beneath the peaks from TL. The reproducibility of the results in this work has shown that this material can be considered a good dosimetric material.

    Palavras-Chave: critical size; doped materials; dose-response relationships; dosimetry; nanoparticles; neodymium; radiation doses; thermoluminescence; x-ray diffraction; yttrium fluorides

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  • IPEN-DOC 24517

    BARBOSA, HELLIOMAR P.; PEDROSO, CASSIO C.S.; FELINTO, MARIA C.F.C. ; MALTA, OSCAR L.; BRITO, HERMI F.. White light emission of the single-phase CaWO4:Dy3+ phosphors by simple synthesis and fast heating. In: INTERNATIONAL CONFERENCE ON LUMINESCENCE, 18th, August 27 - September 01, 2017, João Pessoa, PB. Abstract... 2017. p. 374-374.

    Abstract: Tungstates activated by trivalent rare earth ions (R3+) can be used for many optical devices [1]. Nowadays, there is an increasing interest in white phosphors emitting to application in white-light-emitting devices (WLEDs) replacing the conventional fluorescent lamps due its ecofriendliness and tuneable colours. Here we report preparation as well as the spectroscopic properties of the single phase new highly luminescent white emitting of Dy3+ doped into the CaWO4 materials. The materials were prepared by coprecipitation method at room temperature with stoichiometry aqueous solutions of Na2WO4, CaCl2 and DyCl3 (0.1 to 5.0 mol% of the Ca2+ amount). The as-prepared materials were heated for 22 min between 900 – 1000 W in a domestic microwave oven and using Fe3O4 (60 g) susceptor as heating source. The XPD measurements revealed the CaWO4:Dy3+ particles belong to the tetragonal scheelite phase with I41/a (#88) space group. The emission arising mainly from the 4F9/26H15/2 (blue) and 6H13/2 (yellow) transitions are corresponding to the 488 and 575 nm, respectively (Fig.). At lower doping concentrations the broad band (~420 nm) is due to the WO4 group emission. Increasing the RE3+ doping concentration the main emission lines transitions of the Dy3+ are enhanced. After heating, the 1.0 mol% Dy3+ doped material exhibit a better whitish emission due to the simultaneous presence of broad band of the host in blue region and emission lines at longer wavelengths (Fig.). The lifetimes decrease monotonously in function of the Dy3+ concentration which indicates that the energy transfer from host to the Dy3+ becomes more efficient. These results suggest that CaWO4:Dy3+ could act as a white emitting phosphor in solid state-lighting technology.

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  • IPEN-DOC 26960

    BARBOSA, HELLIOMAR P.; SILVA, IVAN G.N.; FELINTO, MARIA C.F.C. ; TEOTONIO, ERCULES E.S.; MALTA, OSCAR L.; BRITO, HERMI F.. White light emission materials based on simultaneous Tb3+, Eu3+ and Dy3+ doping in CaWO4 single-phased. In: WORLD CHEMISTRY CONGRESS, 46th; ANNUAL MEETING OF THE BRAZILIAN CHEMICAL SOCIETY, 40th; IUPAC GENERAL ASSEMBLY, 49th, July 07-14, 2017, São Paulo, SP. Abstract... Durham, NC, USA: International Union of Pure and Applied Chemistry, 2017.

    Abstract: Tungstates activated by trivalent rare earth ions (RE3+) can be used for many optical devices [1]. Over the last decades, the solid-state lighting sources based on phosphor converted white lightemitting diodes (pc-WLEDs) has improved to overtake fluorescent lighting types because of many advantages such as high ecofriendliness, brightness, low power consumption and fast response time [2]. Here we report preparation and spectroscopic properties of the single phase new highly luminescent white emitting of the Tb3+/Eu3+/Dy3+ triply-doped CaWO4 material. The CaWO4:xTb3+,xEu3+,xDy3+(x mol% of the Ca2+ amount) materials were prepared by fast coprecipitation method at room temperature with stoichiometry aqueous solutions of Na2WO4, CaCl2 and RECl3 (RE3+: Tb, Eu and Dy). The XPD measurements revealed the CaWO4:RE3+ particles belong to the tetragonal scheelite phase with I41/a (#88) space group. The emission spectra exhibit only narrow emission bands arising from the doping Tb3+, Dy3+ and Eu3+ ions. These emission bands are assigned to the 4f transitions from the 4F9/2 (Dy3+), 5D4 (Tb3+) and 5D0 (Eu3+) emitting states to their energy levels corresponding to (in nm): 702 5D07F4(Eu3+), 655 5D07F3(Eu3+), 615 5D07F2(Eu3+), 592 5D07F1(Eu3+), 575 4F9/26H13/2(Dy3+), 544 5D47F5(Tb3+), 488 5D47F6(Tb3+), 478 4F9/26H15/2(Dy3+) (Fig. left). The presence of the emission bands assigned to the doping Dy3+, Tb3+ and Eu3+ ions suggests clear evidence of nonradiative energy transfer from 4F9/2 (Dy3+)5D4 (Tb3+)5D0 (Eu3+) emitter states (Fig. center). The white light emission was mainly reached for 5.0 mol% RE3+ with x: 0.333; y: 0.352 CIE (Commission Internationale l'Éclairage) coordinates (Fig. right). These phosphors could be suitable as triply-doped white light emitters with only single-phased for solid state lighting applications. Since warm white light is preferred for reading, while cold white light is preferred for public lighting the tunability of this single-phase emitting phosphor exhibit promising applications for solid-state lighting.

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  • IPEN-DOC 23753

    LEVY, DENISE ; VILLAVICENCIO, ANNA L.C.H. . Web-based tools to increase public understanding of nuclear technology and food irradiation. International Journal of Social, Behavioral, Educational, Economic, Business and Industrial Engineering; International Scholarly and Scientific Research & Innovation, v. 11, n. 1, p. 70-74, 2017.

    Abstract: Food irradiation is a processing and preservation technique to eliminate insects and parasites and reduce diseasecausing microorganisms. Moreover, the process helps to inhibit sprouting and delay ripening, extending fresh fruits and vegetables shelf-life. Nevertheless, most Brazilian consumers seem to misunderstand the difference between irradiated food and radioactive food and the general public has major concerns about the negative health effects and environmental contamination. Society´s judgment and decision making are directly linked to perceived benefits and risks. The web-based project entitled ‘Scientific information about food irradiation: Internet as a tool to approach science and society’ was created by the Nuclear and Energetic Research Institute (IPEN), in order to offer an interdisciplinary approach to science education, integrating economic, ethical, social and political aspects of food irradiation. This project takes into account that, misinformation and unfounded preconceived ideas impact heavily on the acceptance of irradiated food and purchase intention by the Brazilian consumer. Taking advantage of the potential value of the Internet to enhance communication and education among general public, a research study was carried out regarding the possibilities and trends of Information and Communication Technologies among the Brazilian population. The content includes concepts, definitions and Frequently Asked Questions (FAQ) about processes, safety, advantages, limitations and the possibilities of food irradiation, including health issues, as well as its impacts on the environment. The project counts on eight selfinstructional interactive web courses, situating scientific content in relevant social contexts in order to encourage self-learning and further reflections. Communication is a must to improve public understanding of science. The use of information technology for quality scientific divulgation shall contribute greatly to provide information throughout the country, spreading information to as many people as possible, minimizing geographic distances and stimulating communication and development.

    Palavras-Chave: food processing; irradiation; learning; educational tools; educational facilities; nuclear energy; nuclear engineering; reactor technology; scientific personnel

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  • IPEN-DOC 23779

    LEVY, DENISE ; SORDI, GIAN M.A.A. . Web-based instructional program to improve professional development: recommendations and standards for radioactive facilities in Brazil. International Journal of Social, Behavioral, Educational, Economic, Business and Industrial Engineering; International Scholarly and Scientific Research & Innovation, v. 11, n. 1, p. 75-80, 2017.

    Abstract: This web based project focuses on continuing corporate education and improving workers' skills in Brazilian radioactive facilities throughout the country. The potential of Information and Communication Technologies (ICTs) shall contribute to improve the global communication in this very large country, where it is a strong challenge to ensure high quality professional information to as many people as possible. The main objective of this system is to provide Brazilian radioactive facilities a complete web-based repository - in Portuguese - for research, consultation and information, offering conditions for learning and improving professional and personal skills. UNIPRORAD is a web based system to offer unified programs and inter-related information about radiological protection programs. The content includes the best practices for radioactive facilities in order to meet both national standards and international recommendations published by different organizations over the past decades: International Commission on Radiological Protection (ICRP), International Atomic Energy Agency (IAEA) and National Nuclear Energy Commission (CNEN). The website counts on concepts, definitions and theory about optimization and ionizing radiation monitoring procedures. Moreover, the content presents further discussions related to some national and international recommendations, such as potential exposure, which is currently one of the most important research fields in radiological protection. Only two publications of ICRP develop expressively the issue and there is still a lack of knowledge of fail probabilities, for there are still uncertainties to find effective paths to quantify probabilistically the occurrence of potential exposures and the probabilities to reach a certain level of dose. To respond to this challenge, this project discusses and introduces potential exposures in a more quantitative way than national and international recommendations. Articulating ICRP and AIEA valid recommendations and official reports, in addition to scientific papers published in major international congresses, the website discusses and suggests a number of effective actions towards safety which can be incorporated into labor practice. The WEB platform was created according to corporate public needs, taking into account the development of a robust but flexible system, which can be easily adapted to future demands. ICTs provide a vast array of new communication capabilities and allow to spread information to as many people as possible at low costs and high quality communication. This initiative shall provide opportunities for employees to increase professional skills, stimulating development in this large country where it is an enormous challenge to ensure effective and updated information to geographically distant facilities, minimizing costs and optimizing results.

    Palavras-Chave: nuclear facilities; radioactive waste facilities; education; learning; websites; scientific personnel; standards; educational facilities

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  • IPEN-DOC 24671

    PIERETTI, EURICO F. ; COZZA, RONALDO C.; NEVES, MAURICIO D.M. das . Wear evaluation of the ASTM F138 austenitic stainless steel for biomedical applications treated by optical fiber laser. In: WORLD TRIBOLOGY CONGRESS, 6th, September 17-22, 2017, Beijing, China. Resumo expandido... 2017. p. 1-4.

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  • IPEN-DOC 24342

    GARCIA, VANESSA S.G. ; MATSUSHITA, EDUARDO T.D.; MESQUITA, LETICIA C.A. ; FAVARO, DEBORAH I.T. ; BORRELY, SUELI I. . Water quality and ecotoxicity assessment in surface waters from Cubatão River and surroundings, São Paulo, Brazil. Journal of Water Resource and Protection, v. 09, n. 12, p. 1510-1525, 2017. DOI: 10.4236/jwarp.2017.912096

    Abstract: The monitoring of water bodies means the attempt of protecting vulnerable groups of organisms inhabiting streams and rivers. Industrial and domestic discharges may worsen the water quality and affect biological balance, structure and the functioning of the ecosystem. Cubatão City, is one of the largest industrial centers in Brazil and in Latin America, where the constant discharge of effluents into Cubatão River and its tributaries caused a degradation scenario in the hydrographic basin of the region. The objective of this study was to evaluate the acute and chronic effects of surface water from Cubatão River and two of its tributaries (Perequê and Pilões) by ecotoxicological assays. In addition, physical chemical parameters were analyzed. Ceriodaphnia dubia and Vibrio fischeri were exposed-organisms during the studied period. The study was conducted between 2010 and 2011 in four campaigns and nine sites along the basin of Cubatão River. The ecotoxicity was measured by Vibrio fischeri bioluminescence, EC50 values ranging from 31.25% to 71.61%. In contrast, based on a bioequivalence t-test statistical analysis, the results obtained with Ceriodaphnia dubia revealed no toxicity in the sampling sites. A critical analysis of raw data of luminescence was carried out showing higher values during the 2nd campaign. From the numbers obtained for physical- chemical parameters P5 was far the worst due to chlorides, hardness and conductivity. From the Pearson correlation analysis carried out with toxicity to V. fischeri and the physical chemical parameters, the dissolved oxygen in water resulted in a moderate positive correlation. Sediment contamination was also demonstrated in the region.

    Palavras-Chave: water; water quality; toxicity; surfaces; chronic exposure; chronic exposure; ecosystems; environmental impacts; environment

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  • IPEN-DOC 24374

    ROSTELATO, M.E.C.M. ; SOUZA, D.C.B. ; SOUZA, C.D. ; ZEITUNI, C.A. ; VICENTE, R. ; COSTA, O.L. ; RODRIGUES, B.T. ; MOURA, J.A. ; FEHER, A. ; MOURA, E.S. ; MARQUES, J.R.O. ; CARVALHO, V.S. ; NOGUEIRA, B.R. . Waste management protocols for iridium-192 sources production laboratory used in cancer treatment in Brazil. International Journal of Engineering Research & Science, v. 3, n. 9, p. 45-50, 2017.

    Abstract: Objective: The iridium-192 wired sources production results in radioactive waste that needs to follow the guidelines. The aim of this study is to do a radioactive waste management of wastes from iridium-192 sources production laboratory used in cancer treatment in Brazil. Methods: The wire is acquired in an alloy form with 80% platinum and 20% iridium encapsulated with 100%. Electronic microscopy, X-ray fluorescence, and posterior iridium neutron activation (to determine contaminants) are performed to ensure quality. A 50-cm twisted wire is placed in an aluminum tube. The tube is sealed and place inside the reactor irradiator system and is left for decay during 30 hours to wait for the others undesired activation products to decay. The wire is prepared for treatment with 48 cm length with 192 mCi maximum activity. All the equipment use inside the hot cell must be calibrated every four months. All the waste must be removed from the hot cell. Results: The solid waste is previously characterized in the analysis phase. The contaminants are already known and they are insignificant due to their fast half-life. The iridium-192 half-life is 74.2 days, classified as very short half-life waste. The reminiscent activity is 8mCi. Conclusion: The radioactive waste generated during the I192 wires production is solid, was a short half-life and a weakly activity of 9.7 GBq.g-1. According to the standards, this activity is too high to be discarded into the environment (limit 10 Bq.g-1). The waste must be managed by the R&R (retain e retard) system.

    Palavras-Chave: waste management; radioactive materials; radioactive wastes; neoplasms; therapy; iridium 192; radioactive waste management; sealed sources; brachytherapy

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  • IPEN-DOC 23328

    SILVA, A.C. ; ARAUJO, M.S. ; COSTA E SILVA, D.L. ; MELLO-CASTANHO, S.R.H. . Vitrificação de metais de transição: A estabilidade química no sistema quaternário Na2O-CaO-SiO2-RxOy. In: CONGRESSO BRASILEIRO DE CERAMICA, 61., 04-07 de junho, 2017, Gramado, RS. Anais... 2017. p. 2166-2177.

    Abstract: A estabilização de resíduos industriais contendo metais de transição por meio de processos de vitrificação é de relevância tanto para a saúde pública como a ambiental. O sucesso destas ações depende de que material resultante apresente a necessária estabilidade química frente a meios corrosivos. Uma vez dispersos na massa vítrea fundida, os metais de transição podem assumir coordenações que lhes permite tomar parte na estrutura vítrea resfriada. Desta forma os óxidos destes metais (Cr, Ni, Cu, Zn) considerados genericamente como RxOy, interagem com os óxidos do sistema CaO:Na2O:SiO2, resultando no sistema quaternário CaO:Na2O:SiO2:RxOy, no qual composições adequadamente formuladas podem apresentar apreciável resistência química. No presente trabalho uma composição de matriz vítrea CaO:Na2O:SiO2 (10:30:60 em massa percentual) recebeu adições de metais de transição RxOy provenientes de resíduos industriais (Lama Galvânica) entre 10 e 40 % em massa, de modo a iniciar a exploração da região na qual a incorporação de RxOy no sistema CaO:Na2O:SiO2:RxOy incremente a resistência química. Tal estudo visa iniciar a construção de uma adequada ferramenta para a formulação de vidros contendo metais de transição. Os vidros foram obtidos por fusão (1500°C) em cadinhos de alumina seguida de “Quenching” em molde de aço. A caracterização dos vidros foi realizada por difração de raios-x (DRX), por infravermelho na transformada de Fourier (FTIR) e resistência hidrolítica. Os resultados indicaram alterações na distribuição entre as espécies de sílica Q3 e Q2 na rede vítrea e o aumento da estabilidade química em função da incorporação do RxOy.

    Palavras-Chave: vitrification; industrial wastes; stabilization; sustainable development

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  • IPEN-DOC 24432

    CAREZZATO, G.L. ; COUTO, C.P. ; ROSSI, J.L. ; MARTINEZ, L.G. ; TURRILLAS, X.. A versatile setup in reflection mode for in situ diffraction patterns acquisition from flat polycrystalline specimens bathed in a liquid medium. In: RAU ANNUAL USERS MEETING LNLS/CNPEM, November 22-24, 2017, Campinas, SP. Abstract... 2017. p. 50-50.

    Abstract: A cell to perform in situ diffraction measurements of specimens regularly immersed in a liquid medium has been developed. The assembly (see Fig. 1) has been adapted to work in beamline XRD2 in reflection mode. Basically consists of a polypropylene box with two windows made of poliimide to allow the passage of X-rays (incident and diffracted) at lower angles. The flat sample is placed in the middle of the box that is on top of the goniometer head. For safety reasons the central box is positioned over a tray to avoid spillage of liquid. On the bottom of the cell there is a connection to the pipe linked to the syringe. The syringe is driven by a beamline stepping motor. This way it is easy to synchronise the filling and evacuation of liquid from the cell with the actual data acquisition of diffraction patterns. The idea is to soak the flat specimen with the liquid and then remove it to acquire the diffraction data. This can be done in a sequential way for several hours to monitor the crystalline phases present on the surface (or rather a few microns deep) of the flat specimen. Various reactions can be investigated this way, provided that the sample is flat. Ceramics, metals, and polymers in contact with liquids could be studied. Preliminary tests have been performed in two theta – theta geometry on metal plates in contact with acid solutions to simulate accelerated corrosion. However a large variety of experiments with other geometries, (grazing incidence) could be carried out and of course this assembly could be used on SIRIUS with better time resolution.

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  • IPEN-DOC 24053

    SOUZA, CLAYTON H. ; SHORTO, JULIAN M.B. ; SIQUEIRA, PAULO T.D. ; NUNES, MAIRA G. ; SILVA JUNIOR, IREMAR A. ; YORIYAZ, HELIO . Verification of angular dependence in mosfet detector. In: INTERNATIONAL NUCLEAR ATLANTIC CONFERENCE, October 22-27, 2017, Belo Horizonte, MG. Proceedings... Rio de Janeiro, RJ: Associação Brasileira de Energia Nuclear, 2017.

    Abstract: In vivo dosimetry is an essential tool for quality assurance programs, being a procedure commonly performed with thermoluminescent dosimeters (TLDs) or diodes. However, a type of dosimeter that has increasing popularity in recent years is the metal-oxide-semiconductor field effect transistor (MOSFET) detector. MOSFET dosimeters fulfill all the necessary characteristics to realize in vivo dosimetry since it has a small size, good precision and feasibility of measurement, as well as easy handling. Nevertheless, its true differential is to allow reading of the dose in real time, enabling immediate intervention in the correction of physical parameters deviations and anticipation of small anatomical changes in a patient during treatment. In order for MOSFET dosimeter to be better accepted in clinical routine, information reporting performance should be available frequently. For this reason, this work proposes to verify reproducibility and angular dependence of a standard sensitivity MOSFET dosimeter (TN-502RD-H) for Cs-137 and Co-60 sources. Experimental data were satisfactory and MOSFET dosimeter presented a reproducibility of 3.3% and 2.7% (1 SD) for Cs-137 and Co-60 sources, respectively. In addition, an angular dependence of up to 6.1% and 16.3% for both radioactive sources, respectively. It is conclusive that MOSFET dosimeter TN-502RD-H has satisfactory reproducibility and a considerable angular dependence, mainly for the Co-60 source. This means that although precise measurements, special attention must be taken for applications in certain anatomical regions in a patient.

    Palavras-Chave: cesium 137; cobalt 60; dosemeters; dosimetry; experimental data; in vivo; mosfet; performance

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  • IPEN-DOC 23412

    SILVA, JOSE E.R. da ; JUNQUEIRA, FERNANDO de C. ; LIMA, JOSE R. de . Verificação da estrutura suporte do núcleo do reator IPEN/MB-01 considerando a nova configuração dos internos do núcleo para uso de ECs do tipo placa. São Paulo: Instituto de Pesquisas Energéticas e Nucleares - CEN, Novembro, 2017. (IPEN-CEN-PSE-RMB-005-00-RELT-054-00). Restrito.

    Título do projeto: Reator Multipropósito Brasileiro

    Abstract: Este documento apresenta a verificação da estrutura suporte do núcleo frente aos carregamentos que deverão atuar na mesma devido à substituição de componentes mecânicos associados ao novo núcleo do reator IPEN/MB-01 com o uso de elementos combustíveis (EC) do tipo placa.

    Palavras-Chave: reactor cores; fuel element clusters; fuel plates; control elements; deformation

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  • IPEN-DOC 23099

    POLO, IVON O. ; SANTOS, WILLIAM S. ; ANTONIO, PATRICIA de L. ; CALDAS, LINDA V.E. . Variance reduction technique in a beta radiation beam using an extrapolation chamber. Applied Radiation and Isotopes, v. 128, p. 154-157, 2017. DOI: 10.1016/j.apradiso.2017.06.017

    Abstract: This paper aims to show how the variance reduction technique “Geometry splitting/Russian roulette” improves the statistical error and reduces uncertainties in the determination of the absorbed dose rate in tissue using an extrapolation chamber for beta radiation. The results show that the use of this technique can increase the number of events in the chamber cavity leading to a closer approximation of simulation result with the physical problem. There was a good agreement among the experimental measurements, the certificate of manufacture and the simulation results of the absorbed dose rate values and uncertainties. The absorbed dose rate variation coefficient using the variance reduction technique “Geometry splitting/Russian roulette” was 2.85%.

    Palavras-Chave: absorbed radiation doses; dose rates; extrapolation chambers; monte carlo method; radiation sources

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  • IPEN-DOC 24970

    SANTOS, LAISSA A.B. dos ; DAMATTO, SANDRA R. ; OLIVEIRA, JOSELENE de . Variação sazonal das concentrações de 226Ra, 228Ra e 210Pb das fontes de água mineral do Parque das Águas de Cambuquira e Marimbeiro, MG / Seasonal variation of 226Ra, 228Ra and 210Pb concentrations of the mineral waters from park of waters of Cambuquira and Marimbeiro, MG. In: CONGRESSO BRASILEIRO DE GEOQUIMICA, 16., 22-25 de agosto, 2017, Búzios, RJ. Anais... Rio de Janeiro, RJ: Sociedade Brasileira de Geoquímica, 2017.

    Abstract: Os elementos radioativos podem sem extraídos e arrastados pelas águas subterrâneas, porém quando se fala de águas minerais provindas de fontes subterrâneas uma característica marcante são as concentrações dos radionuclideos 226Ra e 222Rn originalmente dissolvidos. No entanto, outros radionuclídeos naturais como 228Ra e 210Pb, quando presentes, também contribuem para a irradiação interna do individuo. Assim determinou-se as concentrações de 226Ra, 228Ra e 210Pb em dez fontes minerais localizadas no Parque das Águas de Cambuquira e Marimbeiro. Os radionuclideos foram determinados por procedimento radioquimico em quatro coletas em diferentes estações do ano. As concentrações variaram de 4 ±1 mBq/L a 509 ± 32 mBq/L para 226Ra, de < 3,7 ± 0,1 mBq/L a 594 ±35 mBq/L para 228Ra e 5 ± 1 mBq/L a 59 ± 4 mBq/L para 210Pb.

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  • IPEN-DOC 24042

    SILVA, GILBERTO D. ; RODRIGUES JUNIOR, ORLANDO ; DEL MASTRO, NELIDA L. . Variability of Electron Spin Resonance (ESR) signal of γ -irradiated starches. In: INTERNATIONAL NUCLEAR ATLANTIC CONFERENCE, October 22-27, 2017, Belo Horizonte, MG. Proceedings... Rio de Janeiro, RJ: Associação Brasileira de Energia Nuclear, 2017.

    Abstract: Food preservation is one of the practical applications of radiation processing of materials. Starch is an abundant and cheap nutritious biopolymer and also is the material for appropriate food systems and for technical industries. Starch granules are partially crystalline structures composed mainly of two types of starch: amylose, an essentially linear polymer, and amylopectin, with 3-44% of branch points. Electron spin resonance (ESR) spectroscopy is a very powerful and sensitive method for the characterization of the electronic structures of materials with unpaired electrons. The aim of the present work was to monitor the disappearance of the shortlife and long-life free radicals formed during γ-irradiation of 3 different starches. Corn, potato and fermented cassava starches were irradiated in a 60Co source Gammacell 220 with 20 kGy, dose rate around 1 kGy h-1. EPR spectra were obtained at room temperature using a Bruker EMX plus model, X band equipment. The main type of ESR signal from irradiated starch is a singlet with a g-value of about 2.0. The fading of ESR signals was followed for 350 hours, and presents differences among the different starch type reflecting differences in molecular arrangements of starch crystalline and amorphous fractions, although ESR spectra seemed to be common for all starches.

    Palavras-Chave: cassava; cobalt 60; decay; electron spin resonance; maize; potatoes; radiation effects; radicals; spectroscopy; starch

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  • IPEN-DOC 23180

    MERGULHAO, MARCELLO V. ; PODESTA, CARLOS E.; NEVES, MAURICIO D.M. das . Valuation of mechanical properties and microstructural characterization of ASTM F75 Co-Cr alloy obtained by Selective Laser Melting (SLM) and casting techniques. Materials Science Forum, v. 899, p. 323-328, 2017. DOI: 10.4028/www.scientific.net/MSF.899.323

    Abstract: Advances in processes using the powder metallurgy techniques are making this technology competitive compared to the other traditional manufacturing processes, especially in medicine area. The additive rapid prototyping technique – selective laser melting (SLM) was applied in a biomaterial of CoCrMoFe alloy (ASTM F75), to study the mechanical properties and microstructural characterization in comparison between the conventional technique – casting. The gas atomized powder was investigated by their physical (as apparent density, bulk density and flow rate) and the chemical properties. The powder was analyzed using scanning electron microscope with energy-dispersed X-ray spectroscopy (SEM-EDS) and X-ray fluorescence. Specimens of standard samples were manufactured using these techniques to evaluate the mechanical properties as uniaxial tensile (yield strength, rupture tensile and elongation), transverse rupture strength and the micro hardness. The mechanical properties showed higher values in the SLM specimens than the casting specimens. Before the mechanical tests the specimens were examined using optical microscope (OM) and SEM-EDS. The micrographs revealed a microstructure with finer morphology in the SLM technique and the dendrites in the casting technique.

    Palavras-Chave: microstructure; mechanical properties; biological materials; cobalt alloys; chromium alloys; molybdenum alloys; casting; lasers; melting; powder metallurgy

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  • IPEN-DOC 24038

    CARVALHO, PRISCILLA R. ; MUNITA, CASIMIRO S. ; LAPOLLI, ANDRE L. . Validity studies among hierarchical methods of cluster analysis using cophenetic correlation coefficient. In: INTERNATIONAL NUCLEAR ATLANTIC CONFERENCE, October 22-27, 2017, Belo Horizonte, MG. Proceedings... Rio de Janeiro, RJ: Associação Brasileira de Energia Nuclear, 2017.

    Abstract: The literature presents many methods for partitioning of data base, and is difficult choose which is the most suitable, since the various combinations of methods based on different measures of dissimilarity can lead to different patterns of grouping and false interpretations. Nevertheless, little effort has been expended in evaluating these methods empirically using an archaeological data base. In this way, the objective of this work is make a comparative study of the different cluster analysis methods and identify which is the most appropriate. For this, the study was carried out using a data base of the Archaeometric Studies Group from IPEN-CNEN/SP, in which 45 samples of ceramic fragments from three archaeological sites were analyzed by instrumental neutron activation analysis (INAA) which were determinated the mass fraction of 13 elements (As, Ce, Cr, Eu, Fe, Hf, La, Na, Nd, Sc, Sm, Th, U). The methods used for this study were: single linkage, complete linkage, average linkage, centroid and Ward. The validation was done using the cophenetic correlation coefficient and comparing these values the average linkage method obtained better results. A script of the statistical program R with some functions was created to obtain the cophenetic correlation. By means of these values was possible to choose the most appropriate method to be used in the data base.

    Palavras-Chave: archaeology; ceramics; cluster analysis; comparative evaluations; elements; multivariate analysis; quality control; validation

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  • IPEN-DOC 24606

    TEIXEIRA, L.F.L. ; MAZZILLI, B.P. ; NISTI, M.B. ; SAUEIA, C.H.R. . Validation of uranium and thorium determination in sediments by spectrophotometry with Arsenazo III. In: 60 YEARS OF IEA-R1: INTERNATIONAL WORKSHOP ON UTILIZATION OF RESEARCH REACTORS, November 28 - December 01, 2017, São Paulo, SP. Abstract... São Paulo, SP: Instituto de Pesquisas Energéticas e Nucleares, 2017. p. 84-84.

    Abstract: The evaluation of environmental contamination is one of the most important ways to check the anthropogenic interference. Human activities next to a water body, as mining, or on the waterbody, such as transportation ships, can pour unwanted wastes, increasing the concentration of metals or radionuclides. One way to evaluate this contamination on waterbodies is the quantification of radionuclides on sediments. The evaluation of uranium and thorium contamination is an important measurement of anthropogenic interference, because these two natural radionuclides can be found in many places on earth. The are many techniques to determinate the uranium and thorium concentration in sediments samples, and the spectrophotometric method with Arsenazo III is one of the quicker and cheaper method. The Arsenazo-III reacts with both radionuclides, producing a stable complex in low pH condition. The radionuclides were extracted from the sediments samples by an acid digestion, with HNO3, HF and H2O2, on a microwave. The interferences were removed by solvent extraction process, allowing the Arsenazo III react only with the uranium and thorium. The validation process was performed to evaluate if the whole process could reach reliable results with expected quality level. The Limit of Detection (LOD), Limit of Quantification (LOQ), Accuracy (Z-Score) and Precision (Relative Standard Deviation) of each method were evaluated following the INMETRO’s guidance document. The LOD and LOQ of the uranium determination are, respectively, 0.98 and 1.11 ppm, and for thorium determination are, 0.61 and 0.81 ppm, for the analysis of 0.5g of sediments samples. The methods validations were performed using the certified reference material (CRM) IAEA SL-1, for uranium determination, and IAEA SL-3, for thorium determination. Both validations reached satisfactory results of Accuracy and Precision for the analysis of 0.5g of sediments samples.

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  • IPEN-DOC 24104

    DEL NERO, RENATA A. ; NAKANDAKARI, MARCOS V.N.; YORIYAZ, HELIO . Validating a virtual source model based in Monte Carlo Method for profiles and percent deep doses calculation. In: INTERNATIONAL NUCLEAR ATLANTIC CONFERENCE, October 22-27, 2017, Belo Horizonte, MG. Proceedings... Rio de Janeiro, RJ: Associação Brasileira de Energia Nuclear, 2017.

    Abstract: The Monte Carlo method for radiation transport data has been adapted for medical physics application. More specifically, it has received more attention in clinical treatment planning with the development of more efficient computer simulation techniques. In linear accelerator modeling by the Monte Carlo method, the phase space data file (phsp) is used a lot. However, to obtain precision in the results, it is necessary detailed information about the accelerator's head and commonly the supplier does not provide all the necessary data. An alternative to the phsp is the Virtual Source Model (VSM). This alternative approach presents many advantages for the clinical Monte Carlo application. This is the most efficient method for particle generation and can provide an accuracy similar when the phsp is used. This research propose a VSM simulation with the use of a Virtual Flattening Filter (VFF) for profiles and percent deep doses calculation. Two different sizes of open fields (40 x 40 cm² and 40√2 x 40√2 cm²) were used and two different source to surface distance (SSD) were applied: the standard 100 cm and custom SSD of 370 cm, which is applied in radiotherapy treatments of total body irradiation. The data generated by the simulation was analyzed and compared with experimental data to validate the VSM. This current model is easy to build and test.

    Palavras-Chave: calculation methods; computerized simulation; monte carlo method; phase space; radiation dose distributions; radiation transport; v codes; validation; whole-body irradiation

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A pesquisa no RD utiliza os recursos de busca da maioria das bases de dados. No entanto algumas dicas podem auxiliar para obter um resultado mais pertinente.

✔ É possível efetuar a busca de um autor ou um termo em todo o RD, por meio do Buscar no Repositório , isto é, o termo solicitado será localizado em qualquer campo do RD. No entanto esse tipo de pesquisa não é recomendada a não ser que se deseje um resultado amplo e generalizado.

✔ A pesquisa apresentará melhor resultado selecionando um dos filtros disponíveis em Navegar

✔ Os filtros disponíveis em Navegar tais como: Coleções, Ano de publicação, Títulos, Assuntos, Autores, Revista, Tipo de publicação são autoexplicativos. O filtro, Autores IPEN apresenta uma relação com os autores vinculados ao IPEN; o ID Autor IPEN diz respeito ao número único de identificação de cada autor constante no RD e sob o qual estão agrupados todos os seus trabalhos independente das variáveis do seu nome; Tipo de acesso diz respeito à acessibilidade do documento, isto é , sujeito as leis de direitos autorais, ID RT apresenta a relação dos relatórios técnicos, restritos para consulta das comunidades indicadas.

A opção Busca avançada utiliza os conectores da lógica boleana, é o melhor recurso para combinar chaves de busca e obter documentos relevantes à sua pesquisa, utilize os filtros apresentados na caixa de seleção para refinar o resultado de busca. Pode-se adicionar vários filtros a uma mesma busca.

Exemplo:

Buscar os artigos apresentados em um evento internacional de 2015, sobre loss of coolant, do autor Maprelian.

Autor: Maprelian

Título: loss of coolant

Tipo de publicação: Texto completo de evento

Ano de publicação: 2015

✔ Para indexação dos documentos é utilizado o Thesaurus do INIS, especializado na área nuclear e utilizado em todos os países membros da International Atomic Energy Agency – IAEA , por esse motivo, utilize os termos de busca de assunto em inglês; isto não exclui a busca livre por palavras, apenas o resultado pode não ser tão relevante ou pertinente.

✔ 95% do RD apresenta o texto completo do documento com livre acesso, para aqueles que apresentam o significa que e o documento está sujeito as leis de direitos autorais, solicita-se nesses casos contatar a Biblioteca do IPEN, bibl@ipen.br .

✔ Ao efetuar a busca por um autor o RD apresentará uma relação de todos os trabalhos depositados no RD. No lado direito da tela são apresentados os coautores com o número de trabalhos produzidos em conjunto bem como os assuntos abordados e os respectivos anos de publicação agrupados.

✔ O RD disponibiliza um quadro estatístico de produtividade, onde é possível visualizar o número dos trabalhos agrupados por tipo de coleção, a medida que estão sendo depositados no RD.

✔ Na página inicial nas referências são sinalizados todos os autores IPEN, ao clicar nesse símbolo será aberta uma nova página correspondente à aquele autor – trata-se da página do pesquisador.

✔ Na página do pesquisador, é possível verificar, as variações do nome, a relação de todos os trabalhos com texto completo bem como um quadro resumo numérico; há links para o Currículo Lattes e o Google Acadêmico ( quando esse for informado).

ATENÇÃO!

ESTE TEXTO "AJUDA" ESTÁ SUJEITO A ATUALIZAÇÕES CONSTANTES, A MEDIDA QUE NOVAS FUNCIONALIDADES E RECURSOS DE BUSCA FOREM SENDO DESENVOLVIDOS PELAS EQUIPES DA BIBLIOTECA E DA INFORMÁTICA.

O gerenciamento do Repositório está a cargo da Biblioteca do IPEN. Constam neste RI, até o presente momento 20.950 itens que tanto podem ser artigos de periódicos ou de eventos nacionais e internacionais, dissertações e teses, livros, capítulo de livros e relatórios técnicos. Para participar do RI-IPEN é necessário que pelo menos um dos autores tenha vínculo acadêmico ou funcional com o Instituto. Nesta primeira etapa de funcionamento do RI, a coleta das publicações é realizada periodicamente pela equipe da Biblioteca do IPEN, extraindo os dados das bases internacionais tais como a Web of Science, Scopus, INIS, SciElo além de verificar o Currículo Lattes. O RI-IPEN apresenta também um aspecto inovador no seu funcionamento. Por meio de metadados específicos ele está vinculado ao sistema de gerenciamento das atividades do Plano Diretor anual do IPEN (SIGEPI). Com o objetivo de fornecer dados numéricos para a elaboração dos indicadores da Produção Cientifica Institucional, disponibiliza uma tabela estatística registrando em tempo real a inserção de novos itens. Foi criado um metadado que contém um número único para cada integrante da comunidade científica do IPEN. Esse metadado se transformou em um filtro que ao ser acionado apresenta todos os trabalhos de um determinado autor independente das variáveis na forma de citação do seu nome.

A elaboração do projeto do RI do IPEN foi iniciado em novembro de 2013, colocado em operação interna em julho de 2014 e disponibilizado na Internet em junho de 2015. Utiliza o software livre Dspace, desenvolvido pelo Massachusetts Institute of Technology (MIT). Para descrição dos metadados adota o padrão Dublin Core. É compatível com o Protocolo de Arquivos Abertos (OAI) permitindo interoperabilidade com repositórios de âmbito nacional e internacional.

1. Portaria IPEN-CNEN/SP nº 387, que estabeleceu os princípios que nortearam a criação do RDI, clique aqui.


2. A experiência do Instituto de Pesquisas Energéticas e Nucleares (IPEN-CNEN/SP) na criação de um Repositório Digital Institucional – RDI, clique aqui.

O Repositório Digital do IPEN é um equipamento institucional de acesso aberto, criado com o objetivo de reunir, preservar, disponibilizar e conferir maior visibilidade à Produção Científica publicada pelo Instituto, desde sua criação em 1956.

Operando, inicialmente como uma base de dados referencial o Repositório foi disponibilizado na atual plataforma, em junho de 2015. No Repositório está disponível o acesso ao conteúdo digital de artigos de periódicos, eventos, nacionais e internacionais, livros, capítulos, dissertações, teses e relatórios técnicos.

A elaboração do projeto do RI do IPEN foi iniciado em novembro de 2013, colocado em operação interna em julho de 2014 e disponibilizado na Internet em junho de 2015. Utiliza o software livre Dspace, desenvolvido pelo Massachusetts Institute of Technology (MIT). Para descrição dos metadados adota o padrão Dublin Core. É compatível com o Protocolo de Arquivos Abertos (OAI) permitindo interoperabilidade com repositórios de âmbito nacional e internacional.

O gerenciamento do Repositório está a cargo da Biblioteca do IPEN. Constam neste RI, até o presente momento 20.950 itens que tanto podem ser artigos de periódicos ou de eventos nacionais e internacionais, dissertações e teses, livros, capítulo de livros e relatórios técnicos. Para participar do RI-IPEN é necessário que pelo menos um dos autores tenha vínculo acadêmico ou funcional com o Instituto. Nesta primeira etapa de funcionamento do RI, a coleta das publicações é realizada periodicamente pela equipe da Biblioteca do IPEN, extraindo os dados das bases internacionais tais como a Web of Science, Scopus, INIS, SciElo além de verificar o Currículo Lattes. O RI-IPEN apresenta também um aspecto inovador no seu funcionamento. Por meio de metadados específicos ele está vinculado ao sistema de gerenciamento das atividades do Plano Diretor anual do IPEN (SIGEPI). Com o objetivo de fornecer dados numéricos para a elaboração dos indicadores da Produção Cientifica Institucional, disponibiliza uma tabela estatística registrando em tempo real a inserção de novos itens. Foi criado um metadado que contém um número único para cada integrante da comunidade científica do IPEN. Esse metadado se transformou em um filtro que ao ser acionado apresenta todos os trabalhos de um determinado autor independente das variáveis na forma de citação do seu nome.