Navegação Periódicos - Artigos por ano de publicação "2018"

Classificar por: Ordenar: Resultados:

  • IPEN-DOC 24804

    UMBEHAUN, PEDRO E. ; TORRES, WALMIR M. ; SOUZA, JOSE A.B. ; YAMAGUCHI, MITSUO ; SILVA, ANTONIO T. e ; MESQUITA, ROBERTO N. de ; SCURO, NIKOLAS L. ; ANDRADE, DELVONEI A. de . Thermal hydraulic analysis improvement for the IEA-R1 research reactor and fuel assembly design modification. World Journal of Nuclear Science and Technology, v. 8, n. 2, p. 54-69, 2018. DOI: 10.4236/wjnst.2018.82006

    Abstract: This paper presents the sequence of activities to improve the thermal hydraulic analysis of the IEA-R1 research reactor to operate in safe conditions after power upgrade from 2 to 5 MW and core size reduction from 30 to 24 fuel assemblies. A realistic analysis needs the knowledge of the actual operation conditions (heat flow, flow rates) beyond the geometric data and the uncertainties associated with manufacturing and measures. A dummy fuel assembly was designed and constructed to measure the actual flow rate through the core fuel assemblies and its pressure drop. First results showed that the flow distribution over the core is nearly uniform. Nevertheless, the values are below than the calculated ones and the core bypass flow rate is greater than those estimated previously. Based on this, several activities were performed to identify and reduce the bypass flow, such as reduction of the flow rate through the sample irradiators, closing some unnecessary secondary holes on the matrix plate, improvement in the primary flow rate system and better fit of the core components on the matrix plate. A sub-aquatic visual system was used as an important tool to detect some bypass flow path. After these modifications, the fuel assemblies flow rate increased about 13%. Additional tests using the dummy fuel assembly were carried out to measure the internal flow distribution among the rectangular channels. The results showed that the flow rate through the outer channels is 10% - 15% lower than the internal ones. The flow rate in the channel formed between two adjacent fuel assemblies is an estimated parameter and it is difficult to measure because this is an open channel. A new thermal hydraulic analysis of the outermost plates of the fuel assemblies takes into account all this information. Then, a fuel design modification was proposed with the reduction of 50% in the uranium quantity in the outermost fuel plates. In order to avoid the oxidation of the outermost plates by high temperature, low flow rate, a reduction of 50% in the uranium density in the same ones was shown to be adequate to solve the problem.

    Palavras-Chave: thermal hydraulics; reactors; research reactors; uranium; fuel assemblies; iear-1 reactor; flow rate; loss of coolant; materials testing reactors; eccs

    Como referenciar este item
    Icon

  • IPEN-DOC 24778

    PORFIRIO, T.C. ; MUCCILLO, E.N.S. . Thermal and electrical properties of CaCu3Ti4O12 synthesized by soft chemistry route. Journal of Thermal Analysis and Calorimetry, v. 133, n. 2, p. 851–857, 2018. DOI: 10.1007/s10973-018-7184-0

    Abstract: Calcium copper titanate powders were synthesized by a soft chemistry route, aiming to establish a cost-effective solution method to obtain sintered ceramics with giant electric permittivity (ε′) and low dissipation factor (tanδ). Powders and sintered pellets were characterized by several techniques. The thermal decomposition behavior of the porous foam evidences that a hydroxycitrate was formed below 200 °C. Single cubic perovskite-type phase was obtained after calcination of the precursor powder at 700 °C for 5 h. Negligible mass loss occurs above 400 °C. During heating the precursor material, CuO is the first crystallized phase. A giant ε′ and low tanδ are obtained after sintering. The extension of the thermal window of ε′ is wider than those of powders prepared by other methods.

    Palavras-Chave: calcination; calcium compounds; ceramics; copper compounds; copper oxides; differential thermal analysis; dissipation factor; mass transfer; permittivity; perovskite; porous materials; synthesis; titanates

    Como referenciar este item
    Icon

  • IPEN-DOC 25133

    AKBARI-JEYHOUNI, REZA; OCHBELAGH, DARIUSH R.; MAIORINO, JOSE R.; DAURIA, FRANCESCO; STEFANI, GIOVANNI L. de . The utilization of thorium in Small Modular Reactors – Part I: neutronic assessment. Annals of Nuclear Energy, v. 120, p. 422-430, 2018. DOI: 10.1016/j.anucene.2018.06.013

    Abstract: This work presents a neutronic assessment to convert a Small Modular Reactor (SMR) with uranium core to the thorium mixed oxide core with minimum possible changes in the geometry and main parameters of SMR core. This option is due to most of SMR are designed to be strongly poisoned in the beginning of cycle and to have a long cycle. Thorium can be used as an absorber in the beginning of the cycle and also be used as a fertile material during the cycle, it seems to be a good option to use (Th/U)O2 as SMR’s fuel. The main neutronic objectives of this study is achieving longer cycle length for SMR by using the minimum possible amount of burnable poison and soluble boron in comparison with reference core. The Korean SMART reactor as a certified design SMR has been chosen as the reference core. The calculations have been performed by MCNP code for homogeneous and heterogeneous seed and blanket concept fuel assemblies. The results obtained show that the heterogeneous fuel assembly is the one which gives longer cycle length and used lower amount of burnable poison and soluble boron, and also consumes almost the same amount of 235U.

    Palavras-Chave: small modular reactors; thorium; smr reactor; m codes; feasibility studies; neutron reactions; fuel assemblies

    Como referenciar este item
    Icon

  • IPEN-DOC 25116

    MOREIRA, TIANA C.L.; AMATO-LOURENCO, LUIS F.; SILVA, GISELA T. da; ANDRE, CARMEN D.S. de; ANDRE, PAULO A. de; BARROZO, LIGIA V.; SINGER, JULIO M.; SALDIVA, PAULO H.N.; SAIKI, MITIKO ; LOCOSSELLI, GIULIANO M.. The use of tree barks to monitor traffic related air pollution: a case study in São Paulo–Brazil. Frontiers in Environmental Science, v. 6, n. 72, p. 1-12, 2018. DOI: 10.3389/fenvs.2018.00072

    Abstract: The analysis of chemical elements in the barks of trees is an alternative procedure to access spatial heterogeneity of traffic related air pollution. However, the role of tree species in the characterization of the variability of airborne pollution is poorly known. We present an observational study conducted in São Paulo, Brazil, based on the analysis of 498 trees from three common species: Tipuana tipu, Poincianella pluviosa, and Ligustrum sp. We considered ANCOVA models to compare the concentrations of Al, Fe, Zn, Cu, Mn, Ba, and S in the bark (periderm) of trees located close to streets with different levels of traffic intensity controlling for the extension of nearby green areas. The expected trend of increasing elemental concentration in the bark of trees located near streets with greater traffic intensity or close to smaller green areas was only fully evidenced by T. tipu. For instance, the concentrations of Zn, Fe, Al, and Ba increase by 200, 350, 230, and 280% respectively, for trees of this species located near arterial streets when compared to those observed near local streets. On the other hand, the concentrations of Zn, Fe, Al, and Ba are reduced by 41, 45, 50, and 30%, respectively, for trees located near green areas. For P. pluviosa, the capacity to suggest an association between the tree bark concentration of chemical elements with increasing levels of air pollution and presence of green areas was only fully observed for Zn and Cu. For Ligustrum sp., weaker and sometimes non-expected associations between bark concentrations of the chemical elements and either street classification or green area extension were observed. Our results indicate that the choice of species is a key element in the use of tree barks as a biomonitoring tool in urban landscapes. Species like T. tipu, with rough and highly porous bark, are the most appropriate for such purpose.

    Palavras-Chave: monitoring; biological indicators; air pollution; bark; x-ray fluorescence analysis; morphology; urban areas; environment; trees

    Como referenciar este item
    Icon

  • IPEN-DOC 24802

    TANGO, RUBENS N.; ARATA, ANELYSE ; BORGES, ALEXANDRE L.S.; COSTA, ANNA K.F.; PEREIRA, LUCIANO J.; KAMINAGAKURA, ESTELA. The role of new removable complete dentures in stimulated salivary flow and taste perception. Journal of Prosthodontics - Implant Esthetic and Reconstructive Dentistry, v. 27, n. 4, p. 335-339, 2018. DOI: 10.1111/jopr.12507

    Abstract: Purpose: To evaluate the effect of replacement of inadequate complete dentures on salivary flow and taste perception in geriatric patients. Materials and Methods: Thirty-three patients, 13 males and 20 females, with amean age of 64.4 years were submitted to stimulated and unstimulated salivary flow rate and salivary pH measurements, and sense of taste evaluation. Tests were performed 3 months before complete denture substitution and 3 weeks after denture insertion. Results: The mean for unstimulated saliva (USS) was 2.1 ml before and 2.7 ml after replacement (p = 0.003). The mean volume of stimulated saliva was 6.3 ml before and 8.2 ml after replacement (p = 0.004). The pH mean of USS was 7.8 ± 0.44 before and 8.02 ± 0.41 after replacement (p = 0.005). No statistically significant difference was determined in the sense of taste before and 3 weeks after complete denture replacement. Conclusions: The replacement of inadequate complete dentures increases saliva flow; however, it does not improve taste perception.

    Palavras-Chave: dentistry; oral cavity; patients; saliva; salivary glands; prostheses; aged adults; elderly people

    Como referenciar este item
    Icon

  • IPEN-DOC 24776

    PEREIRA, LUIZ A.T. ; ROSSI, JESUALDO L. . The recycling through melting Zircaloy machining chips, preliminary results. Brazilian Journal of Radiation Sciences, v. 6, n. 2, p. 01-11, 2018. DOI: 10.15392/bjrs.v6i2.425

    Abstract: PWR (Pressurized Water Reactor) reactors employ as nuclear fuel UO2 pellets packed in zirconium alloy tubes, called cladding. In the manufacture of the tubes, machining chips are generated which can not be discarded, since the recycling of this material is strategic in terms of nuclear technology, legislation, economics and the environment. These nuclear alloys are very expensive and are not produced in Brazil and are imported for the manufacture of nuclear fuel. In this work, we will discuss methods not yet studied to recycle Zircaloy chips using electron beam furnaces in order to obtain ingots. In addition, it is intended to carry out the melting of new Zircaloy alloys, from the fusion of zirconium sponge produced in IPEN and imported and Zircaloy bars. The mechanical properties and the present phases of the material should be determined, as well as, the characterization of the microstructures by optical microscopy. This work, therefore, aims at the creation of a new line of research where methods will be approached to recycle the chips and to reduce in 30 times by means of fusion the enormous volume of material stored in the form of machining chips, being able to do others components for nuclear or chemical industry use, as well as conducting basic development research.

    Palavras-Chave: cladding; electron beam melting; heat treatments; mechanical properties; microstructure; nuclear fuels; optical microscopy; recycling; zircaloy

    Como referenciar este item
    Icon

  • IPEN-DOC 25074

    CARDOSO, QUEZIA ; SILVA, FRANKS M.; VIEIRA, LIGIA S.; CASINI, JULIO C.S.; SAKATA, SOLANGE K. ; FARIA, RUBENS N. de . The production of reduced graphene oxide by a low-cost vacuum system for supercapacitor applications. Materials Science Forum, v. 930, p. 609-612, 2018. DOI: 10.4028/www.scientific.net/MSF.930.609

    Abstract: Graphene has attracted significant interest because of its excellent electrical properties. However, a practical method for producing graphene on a large scale is yet to be developed. Graphene oxide (GO) can be partially reduced to graphene-like sheets by removing the oxygencontaining groups and recovering the conjugated structure. GO can be produced using inexpensive graphite as the raw material via cost-effective chemical methods. High vacuum and temperature (10−7 mbar and 1100°C, respectively) conditions are well-known to enable the preparation of reduced powder at the laboratory scale. However, a large-scale high vacuum reduction system that can be routinely operated at 10−7 mbar requires considerable initial capital as well as substantial operational and maintenance costs. The current study aims at developing an inexpensive method for the large-scale reduction of graphene oxide. A stainless steel vessel was evacuated to backing-pump pressure (10−2 mbar) and used to process GO at a range of temperatures. The reduction of GO powder at low vacuum pressures was attempted and investigated by X-ray diffraction and Fourier transform infrared spectroscopy. The experimental results of processing GO powder at various temperatures (200–1000°C) at relatively low pressures are reported. The microstructures of the processed materials were investigated using scanning electron microscopy and chemical microanalyses via energy dispersive X-ray analysis.

    Palavras-Chave: capacitors; fourier transformation; graphene; infrared spectra; microstructure; oxides; production; reduction; scanning electron microscopy; temperature dependence; x-ray diffraction

    Como referenciar este item
    Icon

  • IPEN-DOC 25124

    NASCIMENTO, C.R.; ASFORA, V.K.; GONCALVES, J.A.C. ; KHOURY, H.J.; BARROS, V.S.M.; KALIL, L.F.; BUENO, C.C. . The performance of a multi guard ring (MGR) diode for clinical electron beams dosimetry. Applied Radiation and Isotopes, v. 141, p. 112-117, 2018. DOI: 10.1016/j.apradiso.2018.07.002

    Abstract: The dosimetric response of a multi guard ring structure (MGR) diode has been studied with clinical electron beam energies from 5 MeV to 15 MeV. The results showed that the MGR dose response is linear in the range of 5–320 cGy and presents reproducibility with variation coefficients less than 0.4%. The field output factors measured with the MGR agreed within 2% with those measured with an ionization chamber. This study evidences that this diode can be used for clinical electron beam dosimetry.

    Palavras-Chave: electron beams; electron dosimetry; ionization chambers; mev range 01-10; mev range 10-100; rings; security personnel; semiconductor detectors; semiconductor materials

    Como referenciar este item
    Icon

  • IPEN-DOC 24715

    CAPPUZZELLO, F.; AGODI, C.; CAVALLARO, M.; CARBONE, D.; TUDISCO, S.; LO PRESTI, D.; OLIVEIRA, J.R.B.; FINOCCHIARO, P.; COLONNA, M.; RIFUGGIATO, D.; CALABRETTA, L.; CALVO, D.; PANDOLA, L.; ACOSTA, L.; AUERBACH, N.; BELLONE, J.; BIJKER, R.; BONANNO, D.; BONGIOVANNI, D.; BORELLO-LEWIN, T.; BOZTOSUN, I.; BRUNASSO, O.; BURRELLO, S.; CALABRESE, S.; CALANNA, A.; CHAVEZ LOMELI, E.R.; DAGOSTINO, G.; DE FARIA, P.N.; DE GERONIMO, G.; DELAUNAY, F.; DESHMUKH, N.; FERREIRA, J.L.; FISICHELLA, M.; FOTI, A.; GALLO, G.; GARCIA-TECOCOATZI, H.; GRECO, V.; HACISALIHOGLU, A.; IAZZI, F.; INTROZZI, R.; LANZALONE, G.; LAY, J.A.; LA VIA, F.; LENSKE, H.; LINARES, R.; LITRICO, G.; LONGHITANO, F.; LUBIAN, J.; MEDINA, N.H.; MENDES, D.R.; MORALLES, M. ; MUOIO, A.; PAKOU, A.; PETRASCU, H.; PINNA, F.; REITO, S.; RUSSO, A.D.; RUSSO, G.; SANTAGATI, G.; SANTOPINTO, E.; SANTOS, R.B.B.; SGOUROS, O.; SILVEIRA, M.A.G. da; SOLAKCI, S.O.; SOULIOTIS, G.; SOUKERAS, V.; SPATAFORA, A.; TORRESI, D.; MAGANA VSEVOLODOVNA, R.; YILDIRIM, A.; ZAGATTO, V.A.B.. The NUMEN project: NUclear Matrix Elements for Neutrinoless double beta decay. European Physical Journal A, v. 54, n. 5, 2018. DOI: 10.1140/epja/i2018-12509-3

    Abstract: The article describes the main achievements of the NUMEN project together with an updated and detailed overview of the related R&D activities and theoretical developments. NUMEN proposes an innovative technique to access the nuclear matrix elements entering the expression of the lifetime of the double beta decay by cross section measurements of heavy-ion induced Double Charge Exchange (DCE) reactions. Despite the fact that the two processes, namely neutrinoless double beta decay and DCE reactions, are triggered by the weak and strong interaction respectively, important analogies are suggested. The basic point is the coincidence of the initial and final state many-body wave functions in the two types of processes and the formal similarity of the transition operators. First experimental results obtained at the INFN-LNS laboratory for the Ca-40(O-18, Ne-18)(40) Ar reaction at 270 MeV give an encouraging indication on the capability of the proposed technique to access relevant quantitative information. The main experimental tools for this project are the K800 Superconducting Cyclotron and MAGNEX spectrometer. The former is used for the acceleration of the required high resolution and low emittance heavy-ion beams and the latter is the large acceptance magnetic spectrometer for the detection of the ejectiles. The use of the high-order trajectory reconstruction technique, implemented in MAGNEX, allows to reach the experimental resolution and sensitivity required for the accurate measurement of the DCE cross sections at forward angles. However, the tiny values of such cross sections and the resolution requirements demand beam intensities much larger than those manageable with the present facility. The on-going upgrade of the INFN-LNS facilities in this perspective is part of the NUMEN project and will be discussed in the article.

    Palavras-Chave: nuclear matrix; matrix elements; charge-exchange reactions; accelerator experimental facilities; oxygen 18 reactions; oxygen 20; particle identification; radiation detectors; readout systems; superconducting cyclotrons; calibration; counting techniques; target chambers; cross sections; data processing; ion detection; lifetime; magnetic spectrometers; mev range 100-1000; neon 20 reactions; neutrinoless double beta decay

    Como referenciar este item
    Icon

  • IPEN-DOC 25106

    KAFER, KARINE A.; BERNARDI, HEIDE H.; SANTOS, OSMAR de S.; OTUBO, LARISSA ; LIMA, NELSON B. de ; OTUBO, JORGE. The influence of microstructure and mechanical resistance on the shape memory of ECAE processed stainless Fe-Mn-Si-Cr-Ni-Co steel. Materials Research, v. 21, n. 5, 2018. DOI: 10.1590/1980-5373-MR-2017-0958

    Abstract: In the current work, XRD, SEM, EBSD and TEM techniques were used to evaluate the microstructure of stainless Fe-Mn-Si-Cr-Ni-Co shape memory steel processed by ECAE and annealed for one hour at temperatures ranging from 650ºC to 950ºC. The results were then correlated with the mechanical and shape-memory properties of the steel. It was observed that the samples containing large grains and a microstructure free of defects or precipitates presented a high volume fraction of multi-variant thermal martensite and stress-induced martensite, resulting in good shape recovery, owing to the memory effect. The grain refinement and precipitation of second-phase particles decreased the volume fraction and number of martensite variants and considerably increased the mechanical resistance, enhancing the elastic shape recovery. It was shown that shape memory properties were essentially related to the mechanical resistance of the matrix, which in turn was related to the microstructure.

    Palavras-Chave: backscattering; grain size; martensite; mechanical properties; microstructure; scanning electron microscopy; shape memory effect; stainless steels; transmission electron microscopy; x-ray diffraction

    Como referenciar este item
    Icon

  • IPEN-DOC 24345

    VILLAVICENCIO, ANNA L.C.H. ; HELENO, SANDRINA A.; CALHELHA, RICARDO C.; SANTOS-BUELGA, CELESTINO; BARROS, LILLIAN; FERREIRA, ISABEL C.F.R.. The influence of electron beam radiation in the nutritional value, chemical composition and bioactivities of edible flowers of Bauhinia variegata L. var. candida alba Buch.-Ham from Brazil. Food Chemistry, v. 241, p. 163-170, 2018. DOI: 10.1016/j.foodchem.2017.08.093

    Abstract: As edible flowers are highly perishable, irradiation technology can be applied to increase their shelf life, as also for phytosanitary purposes. Herein, flowers of Bauhinia variegata L. var. candida alba Buch.- Ham were submitted to electron beam irradiation at the doses of 0.5, 0.8 and 1 kGy, to study the effects in the nutritional and chemical profiles, and also in antioxidant, cytotoxic and anti-inflammatory activities. The petals of white flowers revealed interesting bioactive properties being kaempferol derivatives the most abundant compounds, especially kaempferol-3-O-rutinoside. The applied irradiation doses did not highly affect the nutritional profile. No changes were produced in cytotoxicity, but the anti-inflammatory activity slightly decreased. However, the antioxidant activity was increased, especially in the dose of 0.5 kGy, in agreement with the higher content in phenolic compounds found at this dose.

    Palavras-Chave: flowers; food; electron beams; radiations; nutrients; chemical composition; biochemistry; decontamination; food processing; radiopreservation; brazil

    Como referenciar este item
    Icon

  • IPEN-DOC 24382

    SILVA, RITA C.A. ; SAIKI, MITIKO ; MOREIRA, EDSON G. ; OLIVEIRA, PAULO T.M.S.. The great egret (Ardea alba) as a bioindicator of trace element contamination in the São Paulo Metropolitan Region, Brazil. Journal of Radioanalytical and Nuclear Chemistry, v. 315, n. 3, p. 447-458, 2018. DOI: 10.1007/s10967-017-5687-y

    Abstract: To investigate great egret as a possible bioindicator of trace element contamination, the concentrations of Br, Cd, Co, Cs, Cu, Fe, Hg, K, Mg, Mn, Na, Rb, Se and Zn were determined in livers of great egrets (Ardea alba) by the methods of Instrumental Neutron Activation Analysis and Atomic Absorption Spectrometry. It was observed that the levels of trace elements found in their livers may indicate contamination of the studied region. Thus, the livers of this species can be considered as a suitable bioindicator of contamination of the aquatic systems in the So Paulo Metropolitan Region.

    Palavras-Chave: birds; contamination; elements; trace amounts; liver; brazil; neutron activation analysis; absorption spectroscopy

    Como referenciar este item
    Icon

  • IPEN-DOC 24785

    SALLES, FERNANDA J.; SATO, ANA P.S.; LUZ, MACIEL S.; FAVARO, DEBORAH I.T. ; FERREIRA, FRANCISCO J.; PAGANINI, WANDERLEY da S.; OLYMPIO, KELLY P.K.. The environmental impact of informal and home productive arrangement in the jewelry and fashion jewelry chain on sanitary sewer system. Environmental Science and Pollution Research, v. 25, n. 11, p. 10701-10713, 2018. DOI: 10.1007/s11356-018-1357-z

    Abstract: The outsourcing informal home practices adopted in jewelry and fashion jewelry chain can cause toxic substance elimination in the effluents and raise a concern for its environmental impact. This study evaluates if this informal work alters the concentration of potentially toxic elements (PTEs: As, Cd, Cr total and Cr-VI, Cu, Hg, Ni, Pb, Sn, and Zn) in the sewage network. The sanitary sewage samples (n = 540) were collected in 15 manholes during two campaigns in three different areas of Limeira-SP, Brazil (industrial area, with informal work and without known industrial/informal activity). The sewage sludge (n = 12), raw (n = 12), and treated sewage (n = 12) were collected in two wastewater treatment plants (WWT: AS and TATU) operating with different treatment process. The PTE determination was performed by ICP-OES, direct mercury analysis, and UV-Vis spectroscopy. Cr-VI, Cu, Ni, and Zn were the only elements above the quantification limit. Four samples exceeded Cu or Zn values permitted to be discharged into sewage system; however, the concentration average was lower than that established by Brazilian legislation. A difference was found between values above and below the 75th percentile for campaign and total organic carbon values (p < 0.015). The AS-treated sewage presented low concentrations of Cu (p < 0.05), Zn (p = 0.02), and Ni (p = 0.01) compared to treated sewage from TATU. In the sludge samples, the Cu means exceeded the limits of the Brazilian legislation (1500 mg kg(-1)) and the Zn results were very close to the limits (2800 mg kg(-1)). The heterogeneity of the results can indicate the sporadic nature of the PTE's sanitary disposal. PTEs used in jewelry and fashion jewelry chain may precipitate on the sludge, where presented high concentrations of Cu and Zn which require controlled destination.

    Palavras-Chave: environmental impacts; ecological concentration; emission spectroscopy; waste water; legislation; water treatment; comparative evaluations; waste water; zinc; sewage sludge; concentration ratio; mercury; brazil; sampling

    Como referenciar este item
    Icon

  • IPEN-DOC 26450

    BARDELLA, FERNANDO ; RODRIGUES, ANDRE M. ; LEAL NETO, RICARDO M. . The use of crystallographic software as educational support to materials science and engineering. Journal of Materials Education, v. 40, n. 3-4, p. 79-106, 2018.

    Abstract: Justified by the lack of proper didatic tools, a systematic review process was executed to verify at what extent existing crystallographic software can support the teaching process and the understanding of crystal structures in materials science and engineering disciplines. A revision protocol was established and executed, where 26 references were selected and analyzed from a total of 804 software from the International Union of Crystallography (IUCr) software database. The research questions were deemed properly answered by this revision, where both a group of top performers (Class A) and gaps not fulfilled by any software, revealed enhancement possibilities and opportunities for development of new software focused on the educational support to materials science and engineering curricula.

    Palavras-Chave: education; crystallography; data processing; computer codes; engineering; educational tools; training

    Como referenciar este item
    Icon

  • IPEN-DOC 25078

    CASTRO, M.C. ; SILVA, N.F. ; CALDAS, L.V.E. . Testing an extrapolation chamber in computed tomography standard beams. Journal of Physics: Conference Series, v. 975, p. 1-4, 2018. DOI: 10.1088/1742-6596/975/1/012066

    Abstract: The computed tomography (CT) is responsible for the highest dose values to the patients. Therefore, the radiation doses in this procedure must be accurate. However, there is no primary standard system for this kind of radiation beam yet. In order to search for a CT primary standard, an extrapolation ionization chamber built at the Calibration Laboratory (LCI) of the Instituto de Pesquisas Energéticas e Nucleares (IPEN), was tested in this work. The results showed to be within the international recommended limits.

    Palavras-Chave: computerized tomography; depth; dosimetry; extrapolation chambers; leakage current; performance testing; stabilization; standards; x-ray sources; brazilian cnen

    Como referenciar este item
    Icon

  • IPEN-DOC 24772

    PACHECO, RAFAEL R. ; ANDRADE, DELVONEI A. de . Technological perspectives for propulsion on nuclear attack submarines. World Journal of Nuclear Science and Technology, v. 8, n. 1, p. 1-10, 2018. DOI: 10.4236/wjnst.2018.81001

    Abstract: This work aims to present the historical context in which the current understanding of the phenomenon of the direct contact condensation started to call the scientific society attention. The development of nuclear power plants Light Water Reactors demanded a safe way to collect and treat the water used to cool the reactor. Some characteristics of this water in a high energetic thermodynamic state made it unsuitable to be directly discharged in the atmosphere. Small room relieves tanks were developed to contain this discharge. These tanks were partially fulfilled with water, and the vapor injection created a vapor plume. In the interface of liquid and vapor, the thermal exchange would be increased by the characteristic turbulence of this region.

    Palavras-Chave: propulsion systems; submarines; nuclear ships; ship propulsion reactors; emergency plans; cooling systems; vapor condensation; heat transfer; water; nuclear energy; nuclear weapons; technology utilization

    Como referenciar este item
    Icon

  • IPEN-DOC 25094

    FREIRE, LUCIANO O. ; ANDRADE, DELVONEI A. de ; MONTERRAIN, DANIEL. A system status definition to improve behavior description in specifications based on constructal law. Open Journal of Applied Sciences, v. 8, n. 8, p. 315-337, 2018. DOI: 10.4236/ojapps.2018.88024

    Abstract: System behavior description using states faces problems like state explosion, lack of clear definition of state, state identification and coordination between multiple agents. The goals of this work are to ease design activity, to reduce engineering efforts, and to mitigate project risks. The proposed way is to improve information flow during design by adding definitions and some protocols or rules for communicating a specification or design description. This work presented an objective definition of system status (way of interaction with the rest of the world) along other concepts. This work focused in definitions as mind entities and their importance to rationalize work and mitigate project risks during design. This article presented some simple examples to illustrate the advantages of each aspect of proposed definition of system status and discussed limits and exceptions for such definition. The key finding was the proposed definition which was the simplest while keeping completeness at a given product breakdown level. Such definition of status enforced formal segregation of needs and solutions, and eased the inclusion of behavior definition in specifications.

    Palavras-Chave: behavior; cooling systems; machining; control systems; systems analysis; engineering; automation; management; control systems; specifications; laws

    Como referenciar este item
    Icon

  • IPEN-DOC 24751

    GONZALES-LORENZO, CARLOS D.; WATANABE, SHIGUEO; CANO, NILO F.; AYALA-ARENAS, JORGE S.; BUENO, CARMEN C. . Synthetic polycrystals of CaSiO3 un-doped and Cd, B, Dy, Eu-doped for gamma and neutron detection. Journal of Luminescence, v. 201, p. 5-10, 2018. DOI: 10.1016/j.jlumin.2018.04.037

    Abstract: The undoped and B, Cd, Dy, Eu doped synthetic CaSiO3 polycrystals were produced in the laboratory. They are very sensitive γ-ray detectors with main prominent TL peak occurring at about 270 °C, this peak was obtained using 4 °C/s heating rate. The TL behavior changes very little by doping with B, Cd and Dy while Eu doping brings changes. These minerals can be used also for neutron dosimetry. Thermal neutrons react with Ca, Si and O through (n, γ) process and γ emitted in this reaction added to γ-rays of the reactor that produces thermal neutrons and are responsible for induction of thermoluminiscence. The TL response of CaSiO3 is linear for dose < 10 Gy and then has a supralinear behavior up to about 7 kGy and saturating beyond.

    Palavras-Chave: calcium silicates; silicate minerals; polycrystals; gamma dosimetry; neutron dosimetry; doped materials; thermoluminescence

    Como referenciar este item
    Icon

  • IPEN-DOC 25214

    SANTOS, S.C. ; RODRIGUES JUNIOR, O. ; CAMPOS, L.L. . Synthesis, processing, and electron paramagnetic resonance response of Y1.98Eu0.02O3 micro rods. International Journal of Modern Physics: Conference Series, v. 48, p. 1860112-1 - 1860112-8, 2018. DOI: 10.1142/S2010194518601126

    Abstract: Innovating dosimetric materials, which includes design and development of new dosimetric materials based on rare earth oxides, is challenging. Yttrium oxide (Y2O3) is one of the most important sesquioxides and presents crystal characteristics that enable doping with rare earth ions, making it a promising material for radiation dosimetry. This paper reports on the development and measurement of Electron Paramagnetic Resonance (EPR) signal response for Y1.98Eu0.02O3 micro rods that have undergone facile low-pressure hydrothermal synthesis and bio-prototyping. Assynthesized powders with narrow sub-micrometer particle size distribution with d50 of 584 nm exhibited a reactive surface, which led to the formation of stable aqueous suspensions by controlling the surface charge density of particles through alkaline pH adjustment. Ceramic samples with dense microstructure were formed by sintering at 1600 ºC for 4h at ambient atmosphere. Y1.98Eu0.02O3 micro rods were irradiated using a 60Co source with doses from 1 to 100 kGy, and EPR spectra were measured at room temperature in X-band microwave frequencies. Sintered samples exhibited linearity of the main EPR signal response from 10 Gy to 10 kGy. Supralinearity was observed for higher doses, which is possibly ascribed to formation of more defects. Using europium as a dopant enhanced the EPR signal of yttrium rods remarkably, due to 4f–4f transitions of the Eu3+ ion. These innovative findings make europium-doped yttrium oxide a promising material for radiation dosimetry.

    Palavras-Chave: synthesis; rare earths; yttrium oxides; electron spin resonance; magnetic resonance; dosimetry; ceramics; europium; doped materials

    Como referenciar este item
    Icon

  • IPEN-DOC 25075

    CASTANHEIRA, BRUNA; TRIBONI, EDUARDO R.; ANDRADE, LUANA dos S.; TRINDADE, FABIANE de J.; OTUBO, LARISSA ; TEIXEIRA, ANTONIO C.S.C.; POLITI, MARIO J.; QUEIROZ, THIAGO B. de; BROCHSZTAIN, SERGIO. Synthesis of novel periodic mesoporous organosilicas containing 1,4,5,8-Naphthalenediimides within the pore walls and their reduction to generate wall-embedded free radicals. Langmuir, v. 34, n. 28, p. 8195-8204, 2018. DOI: 10.1021/acs.langmuir.8b00220

    Abstract: Novel periodic mesoporous organosilicas (PMOs) containing 1,4,5,8-Naphthalenediimide (NDI) chromophores as an integral part of the pore walls were synthesized in acidic conditions, in the presence of inorganic tetraethyl orthosilicate, using triblock copolymer surfactant Pluronic P-123 as a template. The NDI precursor, the bridged silsesquioxane N,N′-bis(3-triethoxysilylpropyl)-1,4,5,8-naphthalenediimide, was synthesized by reaction of 1,4,5,8-naphthalenetetracarboxylic dianhydride with excess 3-aminopropyltriethoxysilane. A series of samples containing up to 19% (weight %) of NDI were prepared (the materials were labeled PMONDIs). 13C and 29Si solid-state nuclear magnetic resonance revealed that the NDI moiety was intact in the PMONDIs and efficiently grafted to the silica network. Samples with up to 16% NDI load presented an ordered two-dimensional-hexagonal mesoscopic structure, according to small-angle X-ray scattering, transmission electron microscopy, and nitrogen adsorption isotherms. Fluorescence spectra of the PMONDIs showed excimer formation upon excitation, suggesting high flexibility of the organic moieties. Reduction of PMONDIs with aqueous sodium dithionite led to the formation of wall-embedded NDI anion radicals, as observed by the appearance of new visible/near-infrared absorption bands. The PMONDIs were also shown to be efficient photocatalysts in the degradation of sulfadiazine, an antibiotic selected here as a model pollutant, which is usually present in water bodies and wastewater.

    Palavras-Chave: carbon 13; copolymers; fluorescence spectroscopy; naphthalene; nuclear magnetic resonance; photocatalysis; pluronics; porous materials; silica; silicon 29; synthesis; transmission electron microscopy

    Como referenciar este item
    Icon

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.