Navegação Periódicos - Artigos por ano de publicação "2017"

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  • IPEN-DOC 24338

    NUNES, ROBERTA M. ; COSTA, DAMARIS ; ORTIZ, NILCE . The use of eucalyptus activated biocarbon for water treatment-adsorption processes. American Journal of Analytical Chemistry, v. 8, n. 8, p. 515-522, 2017. DOI: 10.4236/ajac.2017.88037

    Abstract: A biocarbon after activation process showed the removal percentage of 92% of methylene blue in solution, the equilibrium parameter—RL value was in the interval from 0 to 1, with 46% of surface coverage degree. The Freundlich constant (n) was higher than 1 as an indication of the physical adsorption process. The Radlich-Peterson calculations obtained the higher R2 value which g constant near 1, a high similarity with Langmuir model. Temkin constant B1 was a positive indication of endothermic process. All calculations provided favorable results for the use of activated biocarbon for dye removing and possible for other organic substances.

    Palavras-Chave: carbon; methylene blue; eucalyptuses; metals; toxic materials; pollution; adsorption; water pollution

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  • IPEN-DOC 23045

    FREIRE, LUCIANO O. ; ANDRADE, DELVONEI A. de . The role of nuclear power from a system engineering standpoint. World Journal of Nuclear Science and Technology, v. 7, n. 3, p. 167-188, 2017. DOI: 10.4236/wjnst.2017.73015

    Abstract: This work proposed the application of system engineering methods to identify organizations vital for society, seeking development and well-being. System engineering requires the identification of blocks (or systems), identification of their service functions, identification of states, identification of required quality and identification of constraints. Analyzing modern societies, vital functions were identified and countries behavior was modeled, identifying their states. In this context, nuclear power was found to be fundamental for development and defense because of its inherent advantages for military naval purposes at war. Another striking conclusion is that nuclear power is the best solution for country energy security, more than to avoid climate changes, but to help the nation to resist climate changes. A solution to mitigate the high overnight costs of nuclear power was also proposed. It was demonstrated qualitatively that the adoption of dual purpose mobile nuclear power plants military performances, economic development and risks management.

    Palavras-Chave: engineering; nuclear power; nuclear energy; energy security; climatic change; power reactors

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  • IPEN-DOC 23081

    MIRANDA, REGINA M. de; LOPES, FABIO; ROSARIO, NILTON E. do; YAMASOE, MARCIA A.; LANDULFO, EDUARDO ; ANDRADE, MARIA de F.. The relationship between aerosol particles chemical composition and optical properties to identify the biomass burning contribution to fine particles concentration: a case study for São Paulo city, Brazil. Environmental Monitoring and Assessment, v. 189, n. 6, p. 1-15, 2017. DOI: 10.1007/s10661-016-5659-7

    Abstract: The air quality in the Metropolitan Area of São Paulo (MASP) is primarily determined by the local pollution source contribution, mainly the vehicular fleet, but there is a concern about the role of remote sources to the fine mode particles (PM2.5) concentration and composition. One of the most important remote sources of atmospheric aerosol is the biomass burning emissions from São Paulo state’s inland and from the central and north portions of Brazil. This study presents a synergy of different measurements of atmospheric aerosol chemistry and optical properties in the MASP in order to show how they can be used as a tool to identify particles from local and remote sources. For the clear identification of the local and remote source contribution, aerosol properties measurements at surface level were combined with vertical profiles information. Over 15 days in the austral winter of 2012, particulate matter (PM) was collected using a cascade impactor and a Partisol sampler in São Paulo City. Mass concentrations were determined by gravimetry, black carbon concentrations by reflectance, and trace element concentrations by X-ray fluorescence. Aerosol optical properties were studied using a multifilter rotating shadowband radiometer (MFRSR), a Lidar system and satellite data. Optical properties, concentrations, size distributions, and elemental composition of atmospheric particles were strongly related and varied according to meteorological conditions. During the sampling period, PM mean mass concentrations were 17.4 ± 10.1 and 15.3 ± 6.9 μg/m3 for the fine and coarse fractions, respectively. The mean aerosol optical depths at 415 nm and Ångström exponent (AE) over the whole period were 0.29 ± 0.14 and 1.35 ± 0.11, respectively. Lidar ratios reached values of 75 sr. The analyses of the impacts of an event of biomass burning smoke transport to the São Paulo city revealed significant changing on local aerosol concentrations and optical parameters. The identification of the source contributions, local and remote, to the fine particles in MASP can be more precisely achieved when particle size composition and distribution, vertical profile of aerosols, and air mass trajectories are analyzed in combination.

    Palavras-Chave: urban areas; air quality; aerosol monitoring; biomass; burns; air pollution; air pollution monitoring; chemical composition; optical radar; environment; monitoring

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  • IPEN-DOC 24684

    BELLONI, M. ; CONTI, T. das N.. The need for changes in electric distribution network for the use of the mini and micro on grid generators. Journal “Scientific Israel - Technological Advantages", v. 19, n. 2, p. 52-58, 2017.

    Abstract: It is expected that with the diversification of utilization rates, the increased demand for electricity and the difficulties encountered in hydroelectric generation, promote the acquisition of more renewable energy generators connected to the network. There's no way to keep a nationwide system of interconnected components and mini-generation connected to the network, effectively without the deployment of the smart grid. Through studies carried out in some inverters used in solar generators, it was verified the existence of harmonics that are injected in the distribution network, creating fluctuations of voltage and current. Rectification of the sine wave inverter, and the connection of multiple network generators cause oscillations in both voltage and frequency, making necessary a network that not only identify these fluctuations, but to interpret, going further, as should take measures to mitigate the effects of these oscillations. This requires an intelligent, interconnected network to the central data processing, intuitive and with a certain degree of autonomy, reducing response time to problems, directing and compensating voltage spikes and rectifying the quality of electricity injected by miscellaneous generators connected to the same.

    Palavras-Chave: power distribution systems; electricity; electric power; electric generators; network analysis; renewable energy sources; smart grids; harmonics

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  • IPEN-DOC 23049

    GOMES, LAERCIO ; DENALDI, RAFAEL L. ; MORAES, JAIR R. de ; BALDOCHI, SONIA L. . The luminescence parameters of Yb3+:Er3+-doped LiLa(WO4)2 single crystal grown in the form of fiber for up-conversion green emission. Journal of Luminescence, v. 187, p. 479-485, 2017. DOI: 10.1016/j.jlumin.2017.03.072

    Abstract: This report details the first study of the luminescence properties of a single crystal grown in the form of fiber for prospective application as the gain medium for fiber laser emission at 552 nm. The excited state decay processes related with the 4S3/2→4I15/2 transition in double Yb3+:Er3+-doped LiLa(WO4)2 crystal have been investigated using time-resolved fluorescence spectroscopy with a Er3+ concentration of 0.5 mol% and Yb3+ with 2, 5, 7, 10 and 15 mol%. Selective laser excitation of the 2F5/2 energy level of Yb3+(972 nm) and selective laser excitations of the 4I11/2 and 4I13/2 energy levels of Er3+(972 and 1550 nm), respectively has established that in a similar way to other optical materials, a strong energy-transfer up-conversion by way of a dipole-dipole interactions between an Yb3+ excited and Er3+ ions, the 4F5/2 level (Yb3+) populates the 4S3/2 upper laser level of the 550 nm transition. The 4S3/2 energy level emits luminescence with peaks having the wavelength center at 550 nm with luminescence efficiency increasing from 7% for Er3+ singly doped to 36% for Yb3+(15 mol%) co-doped crystals. The 4S3/2 lifetime of Er3+ is observed to increase due to the saturation of the multiphonon relaxation rate at high excited-state density of Yb3+ ions. At high excited-state density, Yb3+ ions saturates the accepting modes inside of a critical volume of RC=39.4 Å centered at an excited Er3+(4S3/2) ion, by the high-energy phonons generated from emission sideband of Yb3+ ions in Yb(x%):Er(0.5%) crystals. It is established that the green (552 nm) upconversion luminescence of Er3+ is optimized using an Yb3+ concentration of 11.5 mol% for Er(0.5%):LiLa (WO4)2 crystal.

    Palavras-Chave: crystallization; doped materials; energy transfer; erbium ions; excitation; fluorescence spectroscopy; excited states; fibers; lasers; monocrystals; time resolution; tungstates; ytterbium ions

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  • IPEN-DOC 23229

    SOARES, E.P. ; ZARPELON, L.M.C. ; FARIA, R.N. . The influence of Pr and Mg content on the hydrogen decrepitation of LaNi-based battery alloys. Materials Science Forum, v. 899, p. 148-153, 2017. DOI: 10.4028/www.scientific.net/MSF.899.148

    Abstract: This paper reports the results of investigations of the hydrogenation and decrepitation of some LaNi-based hydrogen storage cast ingot alloys. A decrepitation procedure for battery negative electrode alloys has been applied using a combination of hydrogen pressure and heating from room temperature to 773K. It has been shown that the Pr and Mg content have a significant influence on the microstructures of the hydrogenated alloys and decrepitation efficiency. Alloys with high concentration of Pr and Mg required an activation quenching treatment for starting the absorption of hydrogen. The decrepitated materials were characterized by scanning electron microscopy (SEM). Electrodes for alloy discharge capacity studies were produced using a nickel screen and electrochemical measurement were carried out in a standard three-electrode cell. The H content of the negative electrode, expressed as the number o H atoms (n) per formula unit, was determined using the measured storage capacity.

    Palavras-Chave: lanthanum base alloys; nickel alloys; rare earths; transition elements; microanalysis; hydrogen; noise

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  • IPEN-DOC 23075

    MANTILLA, TAIS F.; TURSSI, CECILIA P.; RAMOS-OLIVEIRA, THAYANNE M.; SILVA, CAMILA V. da; SUZUKI, LUIS C. ; FREITAS, PATRICIA M. de. The In Situ effect of titanium tetrafluoride gel on erosion/abrasion progression in human dentin. Brazilian Dental Journal, v. 8, n. 3, p. 337-345, 2017. DOI: 10.1590/0103-6440201601247

    Abstract: Erosion incidence is increasing and its control is still a challenge in clinical practice. This study evaluated 4% TiF4-gel effects on eroded human dentin subjected to in situ erosive/ abrasive episodes. Seventy-two previously eroded dentin slabs (0.05 M citric acid, pH 2.3, 20 min) were allocated to 6 groups (n=12) according to the treatment to be performed during the in situ phase and number of erosive/abrasive cycles, as follows: 4% TiF4-gel applied once (TiF41), twice (TiF42) or three times (TiF43) followed by 1, 2 and 3 erosive/ abrasive cycles, respectively. Gel was applied before the beginning of the next cycle. Control groups were subjected to 1 (C1), 2 (C2) and 3 (C3) erosive/abrasive cycles only. A seventh group (n=12) comprised in vitro uneroded samples (UN) subjected to 3 erosive/ abrasive cycles. Each cycle corresponded to 2 days of erosive (citric acid 0.5%, pH 2.6, 6x/day) and abrasive (electric toothbrush, 10 s/sample, 1 x/day) challenges. Samples were evaluated under profilometry and environmental scanning electron microscopy (ESEM). Atomic force microscopy images (AFM) were also made (n=3). Repeated measures 2-way ANOVA and Tukey test (p<0.001) showed that TiF42, which did not differ from TiF41 and TiF43, revealed a significant reduction in surface loss compared to all control groups. TiF41 and TiF43 showed no significant difference from C1, but both groups demonstrated significantly smaller surface loss than C2 and C3. ESEM and AFM micrographs suggested alterations on treated surfaces compared to samples from control groups, showing reduced diameters of dentinal tubules lumens. Therefore, TiF4 was able to reduce the progression of erosive/abrasive lesions.

    Palavras-Chave: dentistry; titanium; titanium fluorides; scanning electron microscopy; atomic force microscopy; corrosion denting

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  • IPEN-DOC 23092

    MURA, LUIS F.L. ; SANTOS, ADIMIR dos ; DOMINGOS, DOUGLAS B. ; ROSSI, PEDRO C.R. ; JEREZ, ROGERIO . The experimental determination of the 238U(n,gamma) and total fission reaction rates along the pellet radius of the IPEN/MB-01 reactor. Annals of Nuclear Energy, v. 99, p. 399-409, 2017. DOI: 10.1016/j.anucene.2016.09.046

    Abstract: This work presents a new experimental approach to determine experimentally the reaction rate along the pellet radius of a research reactor facility. The methodology employs concentric hollow cylindrical lead collimators together with gamma-ray spectrometry in a special kind of HPGe detector for the discrimination of very low gamma energy emitted by Np-239 and Mo-99. The U-238 neutron capture and total fission rates were inferred, respectively, from the 106.2 keV gamma emitted by Np-239 and from the 140.51 keV gamma-ray emitted by Mo-99. These lower gamma-ray energies allow the thickness of the lead collimator to be small enough so that the correction factors applied to the procedure were minimized. This kind somewhat challenging experiment was successfully performed at the IPEN/MB-01 research reactor facility. The experiments are claimed to be well-defined, and they are suitable for a benchmark. The measured values of the total fission rates are mainly due to the thermal fissions in U-235 since in the IPEN/MB-01 reactor nearly 85% of the total fissions occur in the thermal neutron energy region. The theoretical analyses were performed using MCNP-5 together with the ENDF/B-VII.o library. The analyses reveal a very good agreement between the calculated and experimental results for the U-238 epithermal neutron capture reaction rates. However, the same can not be said for the thermal reaction rates which show discrepancies both in magnitude as well as in the shape of the attenuation of the reaction rates inside of the fuel pellet. The suspected reason for these discrepancies is the shape of the U-235 cross sections below 0.3 eV which might be different from that adopted in the ENDF/B-VII.o library. (C) 2016 Elsevier Ltd. All rights reserved.

    Palavras-Chave: experiment results; uranium 235; uranium 238; uranium dioxide; nuclear reactions; fuel pellets; fission ratio; ipen-mb-1 reactor

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  • IPEN-DOC 23038

    PEREZ, CLARICE F.; GHOBRIL, CARLOS N.; SORDI, GIAN M. ; SAHYUN, ADELIA . The evaluation of the real alpha value in Brazil and its projection until the year 2050. Radiation Protection Dosimetry, v. 173, n. 1-3, p. 69-72, 2017. DOI: 10.1093/rpd/ncw352

    Abstract: When a cost–benefit analysis is applied to the optimization of practices involving radiation protection, the alpha value is used to determine the amount of money required to be invested in a practice to minimize radiation doses to acceptable levels. The alpha value is often linked to the gross domestic product (GDP) per capita, so the monetary reference value of person-Sievert can often be different in each country. Evaluation of the alpha value in Brazil was performed in 1993 and 2000 making use of the procedure advised by ICRP to produce projections up to 2015 and subsequently in 2004 by using the procedure recommended by the IAEA. This paper, in response to the social and economic situation in Brazil, calculates the alpha value and compares it with the projections of the 1993 and 2000 papers and includes a dollar correction to take account of the differences in the purchasing power from that time. This procedure illustrates the significant gap of value in use and that the actual value should be two to three times higher. By GDP per capita, the authors could calculate the alpha value updated to various countries including the European Union and compare them with the official value currently in use. In conclusion, it is believed that all countries that adopt an alpha value should upgrade it to the present day.

    Palavras-Chave: corrections; cost benefit analysis; european union; gross domestic product; human populations; optimization; radiation doses; radiation protection; brazil; iaea; icrp

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  • IPEN-DOC 24351

    MENDES, N.M.F.; MENDES, M.W.D. ; BRESSIANI, A.H.A. ; TAKIISHI, H. . The effect of heat treatment on microstructure and mechanical properties of Ti-8.5Nb-4.5Ta-13Zr alloy. Materials Science Forum, v. 899, p. 389-394, 2017. DOI: 10.4028/www.scientific.net/MSF.899.389

    Abstract: The effects of the heat treatment on the phase transformations, microstructures and mechanical properties of Ti-8.5Nb-4.5Ta-13Zr alloy were studies in this work. Some of the starting powder were obtained by hydrogenation method and homogenized with metallic tantalum in a highenergy planetary mill. The samples were compacted in a uniaxial and cold isostatic presses and then, sintered at 1150 °C for 10 hours under high vacuum. The heat treatments were carried out at the same sintering temperature, above the α / β transus, at different cooling rates such as furnace cooling, air cooling and water quenching. The sintered samples were characterized using the Archimedes density method, X-ray diffraction (XRD) and scanning electron microscopy (SEM). The microhardness was measured using the Vickers indentation (ASTM E384-11 Standard). It was shown that the microstructure of Ti-8.5Nb-4.5Ta-13Zr alloy consists of beta-phase matrix and alpha-phase region of two structures: equiaxed and needle-like grains also known as Widmanstätten structure. The precipitation of the alpha-phase in the beta-phase matrix led to an increase in Vickers microhardness of the alloy which was furnace cooled. Moreover, a few remaining pores were still found and density above 98% was achieved.

    Palavras-Chave: titanium alloys; powder metallurgy; heat treatments; microstructure; mechanical properties; evaluation; phase transformations; x-ray diffraction; scanning electron microscopy

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  • IPEN-DOC 23227

    CUNHA, SANDRA R.; GAROFALO, STEPHANIE A.; SCARAMUCCI, TAIS; ZEZELL, DENISE M. ; ARANHA, ANA C.C.. The association between Nd:YAG laser and desensitizing dentifrices for the treatment of dentin hypersensitivity. Lasers in Medical Science, v. 32, n. 4, p. 873-880, 2017. DOI: 10.1007/s10103-017-2187-9

    Abstract: This study aims to evaluate the association between Nd: YAG laser (with and without a photoabsorber) and two desensitizing dentifrices containing 15% NovaMin or 8% arginine, as potential treatments for dentin hypersensitivity (DH). DH was simulated by EDTA application for 2 min. Specimens were then analyzed with an environmental scanning electron microscope (ESEM) to ensure open dentin tubules (ODT), counted by using ImageJ software. Specimens were randomized into eight groups (n = 10): Laser (L), Laser+ Photoabsorber (LP), Arginine (A), Arginine+Laser (AL), Arginine+Laser+Photoabsorber (ALP), NovaMin (N), NovaMin+Laser (NL), and NovaMin+ Laser+ Photoabsorber (NLP). Laser irradiation was performed with 1 W, 100 mJ, 10 Hz, congruent to 85 J/cm(2); 4 irradiations of 10 s each, with 10 s intervals between them. After treatment, specimens were again analyzed by ESEM and submitted to erosive/abrasive cycling for 5 days. A final ESEM analysis was performed. Data were analyzed with two-way repeated measure ANOVA and Tukey tests (alpha = 0.05). After treatment, groups N, NL, and NLP presented the lower number of ODT, but they did not different from LP, ALP, and AL. Group A presented the highest number of ODT and it did not differ from group L. Groups L, AL, ALP, and LP presented intermediate results, without differing from each other. After cycling, group A presented the highest number of ODT and did not differ significantly from the other groups, except NLP. None of the associations tested presented better tubule occlusion than NovaMin by itself. Arginine was the only treatment that presented improved tubule occlusion when associated with Nd: YAG laser.

    Palavras-Chave: dentin; dentistry; neodymium lasers; lasers; arginine; dentistry; scanning electron microscopy; environment

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  • IPEN-DOC 24417

    GOMES, MAURILIO P. ; SANTOS, IGOR P. dos ; COUTO, CAMILA P. ; MUCSI, CRISTIANO S. ; ROSSI, JESUALDO L. ; COLOSIO, MARCO A.. Têmpera ao ar de insertos de assentos de válvulas obtidos com o aço ferramenta AISI D2. Industrial Heating Brasil, p. 48-52, 2017.

    Palavras-Chave: sintered materials; valves; machining; powder metallurgy; heat treatments

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  • IPEN-DOC 22827

    FANTON, LEONARDO; LIMA, NELSON B. de ; HAYAMA, ALEXANDRA de O.F.; CARAM, RUBENS; FOGAGNOLO, JOAO B.. Texture development in cold deformed and recrystallized Ti–30Nb–4Sn alloy and its effects on hardness and young’s modulus. Advanced Engineering Materials, p. 1-6, 2017. DOI: 10.1002/adem.201600058

    Abstract: This study analyzes the effects of cold deformation and recrystallization on the microstructure, texture evolution, and mechanical properties of Ti–30Nb–4Sn alloy. The samples are cold rolled to reduce their thickness by up to 85%. The most deformed sample is subjected to recrystallization treatment. The crystallographic texture is determined by X-ray pole figures. The 51% deformed sample shows a {203}<010> texture. The 85% deformed sample shows two texture components: {203}<010> and {130}<-310>, while the recrystallized sample shows a fiber texture with the {130} plane parallel to the sample surface. Hardness increases and Young’s modulus tends to decrease in response to increasing deformation. The recrystallized sample shows low hardness and Young’s modulus.

    Palavras-Chave: texture; tin alloys; titanium alloys; niobium alloys; hardness; young modulus; recrystallization; microstructure; mechanical properties; x-ray fluorescence analysis; fluorescence spectroscopy; x-ray diffraction

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  • IPEN-DOC 24468

    MONTEIRO, N.K. ; CANDIDO, G.A.S. ; FONSECA, F.C. . Synthesis of Ru-doped double perovskite anode for SOFC. ECS Transactions, v. 78, n. 01, p. 1245-1252, 2017. DOI: 10.1149/07801.1245ecst

    Abstract: Pr0.5Ba0.5MnO3 was studied as the precursor phase of the double perovskite PrBaMn2O5+δ (PBMO) anode material for solid oxide fuel cells (SOFC). The general properties were studied in both the pristine compound and Ru-doped samples Pr0.5Ba0.5Mn1-xRuxO3 (PBMRu). Ru substitution at the B-site is expected to enhance the catalytic properties of the ceramic towards ethanol or methane fuels. The studied compounds were synthesized by the polymeric precursor method and characterized by thermogravimetric analyses, X-rays diffraction (XRD), and electrical transport properties. The experimental data show PBMO phase formation occurring at ~800°C and single phase compounds at ~1100°C up to ~10 at.% of Ru substituted. Similar ionic radius of Ru3+ and Mn3+ results in little effect on both the crystalline structure and electrical conductivity as compared to the pristine compound.

    Palavras-Chave: perovskite; anodes; solid oxide fuel cells; ruthenium; synthesis

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  • IPEN-DOC 23027

    ANTONIASSI, R.M. ; SILVA, J.C.M. ; OLIVEIRA NETO, A. ; SPINACE, E.V. . Synthesis of Pt+SnO2/C electrocatalysts containing Pt nanoparticleswith preferential (100) orientation for direct ethanol fuel cell. Applied Catalysis B: Environmental, v. 218, p. 91-100, 2017. DOI: 10.1016/j.apcatb.2017.06.031

    Abstract: The synthesis of Pt + SnO2/C electrocatalyst containing cubic Pt nanoparticles with preferential (100) ori-entation was performed by an alcohol-reduction process using KBr as a shape directing agent. The orderof addition of the Pt and Sn precursors and KBr was crucial to obtain cubic Pt particles and a SnO2phasewith small particle sizes highly dispersed on the carbon support. Electrochemical and DEFC experimentsshowed that Pt + SnO2/C electrocatalyst containing Pt nanoparticles with preferential (100) orientationprovided superior activity for EOR, power densities and CO2selectivity compared to Pt + SnO2/C electro-catalyst containing Pt polycrystalline.

    Palavras-Chave: electrocatalysts; synthesis; platinum; tin oxides; carbon; fuel cells; direct ethanol fuel cells; potassium bromides; polycrystals

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  • IPEN-DOC 22446

    PELEIAS JUNIOR, FERNANDO dos S. ; JONES, MATHEW D.; ZEITUNI, CARLOS A. ; ROSTELATO, MARIA E.C.M. ; MOREIRA JUNIOR, PAULO F.. Synthesis of PLGA using a Csub(3)-synmmetric Zr (IV) amine tris(phenolate) alkoxide initiator and the effects of gamma radiation on its properties. Polymer Bulletin, v. 74, p. 91-105, 2017.

    Palavras-Chave: synthesis; organic acids; zirconium; gamma radiation; irradiation; decomposition; radiation effects; thermodynamic properties

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  • IPEN-DOC 23231

    LEAL NETO, RICARDO M. ; SILVA, RAFAEL de A.; FLORIANO, RICARDO; COUTINHO, GRAZIELE C.S. ; FALCAO, RAILSON B. ; LEIVA, DANIEL R.; BOTTA, WALTER J.. Synthesis by high-energy ball milling of MgH2-TiFe composites for hydrogen storage. Materials Science Forum, v. 899, p. 13-18, 2017. DOI: 10.4028/www.scientific.net/MSF.899.13

    Abstract: The aim of this work is to investigate the influence of some processes variables on the microstructure and hydrogen absorption kinetics of MgH2 - X wt.% TiFe composites. Samples were synthesized by high-energy ball milling in a planetary (X = 40, 50, 60) and shaker mill (X = 40) under high-purity argon atmosphere. Commercial MgH2 instead of Mg powder was used in order to reduce adherence on the vial and balls. TiFe powder was previously produced by ball milling a mixture of TiH2 and Fe powders followed by a reaction synthesis at 600ºC. Milled composites samples were characterized by XRD and SEM analysis. Milling time was preliminary investigated (X = 40) in the planetary ball mill (6 to 36h). TiFe particle size reduction was shown to be difficult since they are surrounded by MgH2 matrix. Strong particle reduction was obtained by using a shaker mill only for 2 hours and adding cyclohexane as process control agent. No reaction between MgH2 and TiFe compound was observed in any milled sample. Hydrogen absorption kinetics measurements of the as-milled samples were conducted on an Sieverts' type apparatus at room temperature after hydrogen desorption at 350ºC under vacuum. The best hydrogen kinetics (3 wt% at the first hour) was attained by the planetary milled sample (36 h). Higher hydrogen capacity was observed for the sample milled in the shaker mill (4.0 wt.%), but only after 13h.

    Palavras-Chave: milling; hydrogen storage; magnesium hydrides; composite materials; iron base alloys; titanium

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  • IPEN-DOC 23117

    SILVA, LAURA L.; ALKIMIM, ISABELLA P.; VASQUEZ, PABLO A.S. ; CARDOSO, DILSON. Synthesis and properties of MCM-41 with polymerizable CADMA cationic surfactant. Catalysis Today, v. 289, p. 2-13, 2017. DOI: 10.1016/j.cattod.2016.06.041

    Abstract: The synthesis route of MCM-41 was modified by using a cationic surfactant different from the usual CTMABr (cetyltrimethylammonium bromide). This surfactant, cetylallyldimethylammonium bromide (CADMABr), differs from CTMABr by the substitution of a methyl group located in the hydrophilic head by a polymerizable allyl group. The CADMABr surfactant and the CADMA-MCM-41 hybrid silica were synthesized using different times. Formation of the surfactant was confirmed using elemental analysis (CHN),13C nuclear magnetic resonance (C-13 NMR), and small-angle X-ray scattering (SAXS) applied to the dispersions of different concentrations of the surfactants in water. The aqueous dispersions of CADMABr and the hybrid silicas were irradiated at different doses of gamma (gamma) radiation in order to obtain information about the polymerization of the surfactant. The hybrid silicas were characterized using X-ray diffraction (XRD) for phase identification, together with thermogravimetry (TGA), nitrogen physisorption, and scanning electron microscopy (SEM). The catalytic properties of the silicas were evaluated using the transesterification reaction of monoalcohols as a model for application in biodiesel manufacture. (C) 2016 Elsevier B.V. All rights reserved.

    Palavras-Chave: mobility; synthesis; catalysis; polymerization; ionizing radiations; radiations

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  • IPEN-DOC 23829

    MISSO, AGATHA M. ; BRITO, HEMI F.; RODRIGUES, LUCAS C.V.; MORAIS, VINICIUS R. ; YAMAGATA, CHIEKO . Synthesis and characterization of CaMgSi2O6 activated by Eu2+. Materials Science Forum, v. 881, p. 30-34, 2017. DOI: 10.4028/www.scientific.net/MSF.881.30

    Abstract: Rare earth silicate based MnMgSi2O5+n (M = Ca, Sr or Ba and n=1-2) phosphors, have attracted interest of researchers due to their high efficiency as a host, excellent thermal and chemical stability and high brightness adding to their low cost. These phosphors showed great potential in various applications such as fluorescent lamps, white light emitting diodes, and display components. High temperature solid-state reactions are usually employed to synthesize those compounds. This paper proposes an alternative method of obtaining nanophosphor host based on Eu-doped CaMgSi2O6 (CMS:Eu), persistent luminescence phosphor. Sol gel technique combined to a modified molten salt method was used. The resulted powder was calcined for 3h under an atmosphere of 5% H2 and 95% Ar2. Phase identification by XRD and the measurements of photoluminescence (PL) and photoluminescence excitation (PLE) were performed. Single phased CMS:Eu with persistent luminescence characteristics was prepared.

    Palavras-Chave: silicates; phosphors; synthesis; alkaline earth metals; europium; photoluminescence; x-ray diffraction

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  • IPEN-DOC 26922

    KIBRIT, EDUARDO ; AQUINO, AFONSO R. de ; MELLO, ADRIANA M. de; NASCIMENTO, PAULO T. de S.. Sustainable operations in nuclear research reactors: a bibliographical study. atw - International Journal for Nuclear Power, v. 62, n. 10, p. 589-596, 2017.

    Palavras-Chave: bibliographies; radioactive waste management; reactor operation; recycling; research reactors; sustainability; document types; management; operation; reactor life cycle; reactors; research and test reactors; waste management

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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.