IPEN: Recent submissions

  • IPEN-DOC 27420

    VIANA, J.L.; SA, R.C.L.; ARAUJO, T.E.S.; RIBEIRO, R.P.; RANGEL, E.C.; CRUZ, N.C.; MARTINEZ, L.G. ; BOCK, E.G.P.. Filmes finos de alumina em substratos de alumínio 5052 por processo de Oxidação Eletrolítica à Plasma. The Academic Society Journal, v. 4, n. 3, p. 167-180, 2020. DOI: 10.32640/tasj.2020.3.167

    Abstract: A alumina, ou óxido de alumínio, tem diversas aplicações como Biomaterial, além de ser utilizada em ferramentas de usinagem, retificas, isolamento térmico, blindagens, refratários para fornos de aquecimento, isoladores elétricos, componentes eletrônicos, devido a sua elevada resistência a altas temperaturas, dureza, resistência mecânica e resistência química. Sua obtenção é decorrente de processos intermediários da fabricação do alumínio primário e também de processos de deposição físicos e químicos. Este trabalho tem como objetivo a obtenção de filmes finos de alumina por meio do processo de Oxidação Eletrolítica à Plasma ou Plasma Eletrolítico de Oxidação (PEO), usando como substrato a liga de alumínio 5052. Este estudo serve de base para aplicações de filmes de finos de alumina em rotores de bombas de sangue centrífugas implantáveis, usadas como dispositivos de assistência ventricular desenvolvidos pelo Laboratório de Bioengenharia e Biomateriais do Instituto Federal de Educação, Ciência e Tecnologia de São Paulo. As amostras foram preparadas com a mesma área superficial do rotor, visando simular o mesmo comportamento da deposição do filme no rotor e, desta forma, estudar a morfologia em diferentes tempos e energias de oxidação e como a influência do tempo e da energia na geração dos micro-arcos de plasma agem na formação do filme de alumina. A caracterização do filme foi realizada por Microscopia Eletrônica de Varredura, Espectroscopia por Energia Dispersiva e Difração de Raios X. Os filmes cerâmicos no PEO são criados através da reação da solução eletrolítica com as descargas elétricas produzidas por uma fonte, sendo depositados na superfície das amostras através de micro arcos. Em trabalhos futuros os filmes serão testados quanto à sua viabilidade celular e também serão avaliados como recobrimento interno de bombas de sangue centrífugas implantáveis para utilização em dispositivos de assistência ventricular.

    Palavras-Chave: aluminium oxides; thin films; oxidation; electrolytes; plasma; blood cells; blood flow; blood circulation; heart failure; biological materials; equipment

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  • IPEN-DOC 27419

    SILVA, FELIPE C.; TUNES, MATHEUS A.; SAGAS, JULIO C.; FONTANA, LUIS C.; LIMA, NELSON B. de ; SCHON, CLAUDIO G.. Mechanical properties of homogeneous and nitrogen graded TiN thin films. Thin Solid Films, v. 710, p. 1-10, 2020. DOI: 10.1016/j.tsf.2020.138268

    Abstract: Coating of metallic industrial parts with titanium nitride (TiN) is widely used with the aim to improve the mechanical and tribological properties of these parts. In the present work, TiN films were deposited via grid-assisted magnetron sputtering on aluminium substrates. The films were grown under different substrate bias voltage (-40, -75 or -100 V) and two different modes of nitrogen supply during deposition (constant and variable), resulting in homogeneous and N-graded films. The results of tension fractures observed in situ were correlated with the film microstructure and residual stress levels obtained through grazing incidence X-ray diffraction measurements. Elastic properties of the films were analysed via nanoindentation and adhesive properties were investigated by nanoscratching tests. Results show that the delamination load of the graded films is higher than in the homogeneous counterparts, suggesting the graded film have improved tribological properties.

    Palavras-Chave: thin films; coatings; titanium nitrides; mechanical properties; fractures; stresses; x-ray diffraction; ceramics; nitrogen

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  • IPEN-DOC 27418

    ARAUJO, JOAO V. de S. ; MILAGRE, MARIANA X. ; FERREIRA, RAPHAEL O.; MACHADO, CARULINE de S.C. ; ABREU, CAIO P. de ; COSTA, ISOLDA . Microstructural characteristics of the Al alloys: the dissimilarities among the 2XXX alloys series used in aircraft structures. Metallography, Microstructure, and Analysis, v. 9, n. 5, p. 744-758, 2020. DOI: 10.1007/s13632-020-00688-5

    Abstract: Microstructure characteristics of two high-strength aluminum alloys, the 2024-T3 Al–Cu–Mg, and the new generation Al–Cu–Li alloy 2198, in the T8 and T851 tempers, were investigated in this study. For this purpose, microstructural and statistical analyses were carried out. The results showed equiaxed grains for the 2024-T3 and 2198-T851 alloys, whereas, elongated grains for the 2198-T8. Besides, the 2198-T851 alloy displayed slip bands in the grains due to the stretching stage, “51”. The 2024-T3 alloy showed at least two types of constituent particles, Al–Cu–Mg and Al–Cu–Mn–Fe–(Si); whereas Al–Cu–Li alloys showed only one type, Al–Cu–Fe, in their composition. Statistical analyses showed that the percentage of area covered by constituent particles was larger in the 2024-T3 alloy compared to the 2198 in both tempers, T8 and T851. On the other hand, the Al–Cu–Li alloys showed higher microhardness values relatively to the Al–Cu one. The differences among the nanometric phases present in Al–Cu and Al–Cu–Li alloys were analyzed by transmission electron microscopy. All the results were related to the different chemical composition and industrial thermomechanical processing of each alloy.

    Palavras-Chave: alloys; microstructure; aluminium alloys; copper alloys; magnesium alloys; lithium alloys; statistics; systems analysis; corrosion; corrosion resistant alloys; scanning electron microscopy; transmission electron microscopy; nanoparticles

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  • IPEN-DOC 27417

    BUGARIN, A.F.S. ; ABREU, C.P. de ; TERADA, M.; MELO, H.G. de; COSTA, I. . Effect of friction stir welding (FSW) on the electrochemical behavior and galvanic coupling of AA2024-T3 and AA7475-T651. Materials Today Communications, v. 25, p. 1-11, 2020. DOI: 10.1016/j.mtcomm.2020.101591

    Abstract: In this study, the local electrochemical activity of AA2024-T3 and AA7475-T761 joined by friction stir welding (FSW) was investigated as a function of time by electrochemical tests in 0.01 mol L−1 NaCl solution using a mini cell. The welding procedure resulted in increased electrochemical activity of the weld affected zones of both alloys, which electrochemical activities increased with immersion time, as demonstrated by the electrochemical behavior. In the heat affected zone (HAZ) and the thermomechanically affected zone (TMAZ) of AA7475-T651 the increased activity was due to precipitation of η phase at the grain boundaries stimulated by thermomechanical effects. On the other hand, the enhanced activity in the TMAZ/HAZ of the AA2024-T3 was associated to a large concentration of copper rich cathodic particles broken by tool rotation that were spread along this zone. However, the zone of highest electrochemical activity was the stir zone (SZ) and this was ascribed to galvanic coupling between the two alloys, AA2024-T3 and the AA7475-T651, where the former acted as cathodic and the latter as anodic area.

    Palavras-Chave: welding; friction welding; tensile properties; miscrostructure; corrosion; corrosion resistance; aluminium alloys

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  • IPEN-DOC 27416

    FARIA, MARCELA E.M. ; LEITE, MARINA M.; ICHIKAWA, RODRIGO U. ; VICHI, FLAVIO M.; TURRILLAS, X. ; MARTINEZ, L.G. . Thickness estimation of TiO2-based nanotubes using X-ray diffraction techniques. Materials Science Forum, v. 1012, p. 179-184, 2020. DOI: 10.4028/www.scientific.net/MSF.1012.179

    Abstract: TiO2-based nanotubes are a very promising material with many applications in solar cells, biomedical devices, gas sensors, hydrogen generation, supercapacitors, and lithium batteries, among others. Nanotube thickness is a very important property since it is related to electronic and surface mechanics. In this sense, transmission electron microscopy (TEM) can be used. However, it can be difficult to acquire a good TEM image because the transversal section of the nanotubes needs to be visible. In this work, TiO2-based nanotubes obtained via hydrothermal synthesis were studied using X-ray line profile analysis. Scherrer and Single-Line methods provided consistent results for the thickness of the nanotubes (≃ 5 nm) when compared with TEM. Additionally, Single-Line method was also applied to estimate the microstrain. The advantage of using XRD is given by the fact that it is a quick and statistically significant analysis when compared with TEM. The results show that XRD can be used as a rapid and reliable alternative for the thickness estimation of nanotubes.

    Palavras-Chave: x-ray diffraction; titanium oxides; nanotubes; transmission electron microscopy; hydrothermal synthesis; thickness; equations

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  • IPEN-DOC 27415

    CRUZ, P.V.D. ; COSENTINO, I.C. ; GALEGO, E. ; YOSHIKAWA, D.S. ; FARIA, R.N. . The effect of vacuum annealing and HDDR processing on the electrochemical characteristics of activated carbon and graphene oxide for the production of supercapacitors electrodes. Materials Science Forum, v. 1012, p. 125-130, 2020. DOI: 10.4028/www.scientific.net/MSF.1012.125

    Abstract: Electric double-layer capacitors prepared using activated carbons have been subjected to vacuum heat treatments at low and high temperatures (200, 400, 600, 800 and 1000oC). The electrodes have been tested at a potential of 1.1 V employing a KOH electrolyte (1.0 and 6.0 mol.L-1). The effect of or HDDR upon the electrical properties has been investigated by cyclic voltammetry. It has been shown that the specific capacitance at 5 msV-1 increases from 50 Fg-1 to 130 Fg-1 after a heat treatment at 400oC for 1 hour under back pump vacuum. At 400°C the diminution in the specific capacitance with higher scanning rate (10 msV-1) was much less pronounced (from 130 Fg-1 to 100 Fg-1). Equivalent series resistance (ESR) and equivalent parallel resistance of supercapacitors electrodes have also been investigated. Internal resistances of the supercapacitors were calculated using the galvanostatic curves at current densities (100 mAg-1). A compositional and morphological evaluation of these electrodes showed no significant change on the activated carbon structure.

    Palavras-Chave: electrochemistry; capacitive energy storage equipment; hydrogenation; graphene; activated carbon; energy storage; capacitance

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  • IPEN-DOC 27414

    ARAUJO, S.G. ; LANDINI, L. ; SALVADOR, V.L.R. ; SCAPIN, M.A. ; MASSANARES, B.F. ; URBANINHO, A.B. . Study of the feasibility of biodiesel production, from vegetable oils and catalysts of seafood residues, in a batch hydrogenation reaction unit, assisted by microwave and conventional heating. Materials Science Forum, v. 1012, p. 483-488, 2020. DOI: 10.4028/www.scientific.net/MSF.1012.483

    Abstract: In this work, it was proposed to study the feasibility of biodiesel production, from residues of vegetable oils used in domestic activities, employing (CaCO3) shells prepared like calcium oxide (CaO) as catalysts, in a batch reaction unit, on bench scale, installed at IPENCNEN/ SP. This unit is capable of operating with high pressure hydrogen gas (up to 200bar) and high temperature (up to 500°C, using microwave - MW (2.450MHz, with up to 2kW continuous and 8kW pulsed) and conventional heating – (electric) MC. In the tests, the oil load (mL), type and mass of catalyst, with or without hydrogen gas pressure (bar), temperature (°C), reaction time (h), microwave power (W), the speed of the load (rpm) agitation and the conventional heating were evaluated. The analytical determinations of the samples were carried out by means of density, gas chromatography (GC) and X-ray fluorescence. Data were collected in order to be compared with other methodologies, already used in the literature. The purpose of this work was to analyze the efficiency of the use of these types of catalysts and oils in the production of biodiesel, as an alternative technology. The Ca and CaO contents found in the pink shell, before and after the calcination, were 36.2% and 98.8%, respectively. The best result obtained for the density was 0.875182g/cm3, for the test with 4g of calcined shell catalyst and reaction of 1h. As to the methyl ester content, the highest result was 95.33%, in a test with 4g of catalyst and reaction of 3h. In the non-calcined shell test (22.5g), although the amount of mass used was much larger (5% of the oil mass), the ester content was very low, 2.11%.

    Palavras-Chave: biodiesel fuels; feasibility studies; residues; vegetable oils; catalysts; calcium oxides; calcium carbonates; alternative fuels; seafood; waste disposal

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  • IPEN-DOC 27413

    SILVA, PAULA M. da ; SERNA, MARILENE M. ; GALEGO, EGUIBERTO ; FARIA, RUBENS N. . Study of supercapacitors for use in dye sensitized solar cells. Materials Science Forum, v. 1012, p. 114-118, 2020. DOI: 10.4028/www.scientific.net/MSF.1012.114

    Abstract: The storage of energy generated by photovoltaic system is one problem of it. In this aspect, integrated energy conversion and storage systems, IECSS, using supercapacitors are presented as a solution. Dye sensitized solar cell becomes a main candidate for use in IECSS due its variety of applications. Recent studies shown that zinc oxide (ZnO) is a natural candidate for use in solar cells and supercapacitor due to its high energy density of the order 650 A g-1. The aims of this paper were: i) the study of the influence of the morfology of nanostructured ZnO nanoparticles obtained by the hydrothermal method using distincts complexing agents: etylenediaminetetraacetic acid (EDTA); hexamethyltetramine (HMT) and diaminometanal (urea), besides commercial ZnO; ii) study of the ZnO and activated carbon at ratio X:Y of 10:90, 20:80 and 30:70 in proportion of mass (%) in the preparation of electrodes. The commercial ZnO, which presents particles with spherical and porous morphology, presented the best capacitance result 8.38 Fg-1 at 10:90 ratio, that demonstrates the ZnO is an excellent candidate for material for supercapacitor coupled with dye solar cell.

    Palavras-Chave: capacitive energy storage equipment; capacitors; energy storage; zinc oxides; solar cells; sensitizers; electrodes; hydrothermal systems

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  • IPEN-DOC 27412

    REZENDE, RENATO P. ; NEVES, MAURICIO D.M. das . Microstructural characterization of joints of Inconel 718 brazed on vacuum furnace. Materials Science Forum, v. 1012, p. 354-359, 2020. DOI: 10.4028/www.scientific.net/MSF.1012.354

    Abstract: The spacer grids are part of the Fuel Element (FE) set of the PWR (Pressurized Water Reactor) type reactor. These grids maintain the position of the fuel rods within the arrangement of the FE, conserving among them the spacing necessary for the operation of the reactor. The grids are manufactured from the union of the intersecting points of stamped strips of Base Material (BM) Inconel 718, by a joint process called brazing. The addition metal (AM) used consists of a brazing paste based on Ni-Cr-P (nickel-chromium-phosphorus), which is added dropwise in the intersection of grids with a clearance of 0.025 mm. For this purpose, Inconel 718 smooth strips of 0.35 mm thick nickel plated samples were prepared, the AM was added and the vacuum oven was 10-3 mbar, in different time and temperatures. The samples were prepared by metallography and characterized using optical microscopy (OM), scanning electron microscopy (SEM) and mechanical microhardness test. The purpose of this work is to characterize the brazing joint by means evaluate the size of precipitates and the different compounds formed in the joint. It was found different precipitates composed mainly of titanium and niobium. Phosphorus rich phases were found in the brazed region. The mean hardness of the BM was 469 ± 12 HV and in the joint region hardness of 1345 ± 34 HV was found in the lighter phases.

    Palavras-Chave: fuel elements; inconel 718; microstructure; spacers; metals; brazing; precipitation; grids

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  • IPEN-DOC 27411

    CRUZ, RICARDO A. da; SANTOS, GIVANILDO A. dos; NASCIMENTO, MAURICIO S.; FRAJUCA, CARLOS; NAKAMOTO, FRANCISCO Y.; SILVA, MARCIO R. da; SANTOS, VINICIUS T. dos; BATALHA, GILMAR F.; COUTO, ANTONIO A. . Microstructural characterization and mathematical modeling for determination of volume fraction of eutectoid mixture of the Cu-8.5wt% Sn alloy obtained by unidirectional upward solidification. Materials Science Forum, v. 1012, p. 302-307, 2020. DOI: 10.4028/www.scientific.net/MSF.1012.302

    Abstract: The Cu-8.5wt % Sn alloy presents an extensive microsegregation during its solidification. That microsegregation results in the formation of a eutectoid mixture, which is detrimental to subsequent forming processes. This study deals with the influence of solidification time and cooling rate on the microstructure of that alloy. The unidirectional solidification technique allowed the acquisition of thermal data. The optical microscopy enabled the microstructural characterization of the material, the measurement of dendrite arm spacings and the quantification of the volume fraction of the eutectoid mixture. A semi-analytical mathematical model was proposed to estimate the volume fraction of the eutectoid mixture. The model expresses the volume fraction as an implicit function of the Fourier number. The results showed that the microstructure is dendritic and that the characteristic spacings increase with the solidification time between the liquidus and the peritectic temperatures. The data also showed that for higher cooling rates the dendrite arm spacings are smaller and that there is a tendency for the volume fraction of eutectoid mixture in the columnar zone to increase with the Fourier number and to decrease with the cooling rate. The proposed model allowed obtaining values of volume fraction with the same order of magnitude of the experimental data, but with behavior tendency opposite to that observed.

    Palavras-Chave: microstructure; solidification; segregation; eutectoids; copper alloys; tin alloys; mathematical models

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  • IPEN-DOC 27410

    BENITEZ JARA, F.G. ; CRUZ, P.D.V. ; BARBOSA, L.P. ; CASINI, J.C.S.; SAKATA, S.K. ; PERUZZI, A.J.; FARIA, R.N. . Low-temperature reduction of graphene oxide using the HDDR process for electrochemical supercapacitor applications. Materials Science Forum, v. 1012, p. 141-146, 2020. DOI: 10.4028/www.scientific.net/MSF.1012.141

    Abstract: In the present work, attempts of reducing a graphene oxide powder using a low temperature hydrogenation disproportionation desorption and the recombination process (L-HDDR) has been carried out. A lower processing temperature in large scale production is significant when costs are concerned. Graphite oxide was prepared using a modified Hummers’ method dispersed in ethanol and exfoliated using ultrasonication to produce Graphene Oxide (GO). Investigations have been carried out by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The experimental results of L-HDDR processing graphene oxide powder, using unmixed hydrogen at 400°C and relatively low pressures (<2 bars) have been reported. X-ray diffraction patterns showed a reduction of graphene oxide with the L-HDDR process. The results showed that both processes, the L-HDDR as well as the standard HDDR, may be applied to the reduction of graphene oxide in order to produce supercapacitor materials. The advantage of employing the L-HDDR process is a relatively low temperature reducing the cost of treatment, what is a very important factor for producing a large amount of material. Thus, the L-HDDR process has been considered a promising alternative method of reducing graphene oxide with efficiency, with the possibility of large scale production.

    Palavras-Chave: graphene; capacitors; energy storage; capacitance; equivalent circuits; hydrogenation; desorption; recombination

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  • IPEN-DOC 27409

    SANTOS, GIVANILDO A. dos; RIBEIRO, ALEXANDRE N.; NASCIMENTO, MAURICIO S.; FRAJUCA, CARLOS; NAKAMOTO, FRANCISCO Y.; SILVA, MARCIO R. da; SANTOS, VINICIUS T. dos; BATALHA, GILMAR F.; COUTO, ANTONIO A. . Influence of the thermal parameters on the microstructure, corrosion resistance and hardness on the unidirectional solidification of Al-10wt% Si-5wt% Cu alloy. Materials Science Forum, v. 1012, p. 308-313, 2020. DOI: 10.4028/www.scientific.net/MSF.1012.308

    Abstract: This study aims to correlate thermal parameters in the directional solidification of Al- 10wt% Si-5wt% Cu alloy with the resulting microstructure and, in addition, with hardness and corrosion resistance. The results include primary dendritic arm spacing (PDAS), tip growth rate (VL), cooling rate (TR), scanning electron micrographs (SEM), hardness values and corrosion resistance parameters obtained by electrochemical impedance spectroscopy (EIS) and by the Tafel extrapolation method, conducted in 3% (m/v) NaCl solution at room temperature. The results show that coarser PDAS exhibit a tendency to increase in corrosion resistance, except in the positions with higher concentrations of the intermetallic compound Al2Cu, that surrounded by an aluminum rich phase tends to have a higher resistance to corrosion. The hardness values remained constant.

    Palavras-Chave: solidification; thermal analysis; microstructure; corrosion resistance; copper alloys; alloys; hardness; intermetallic compounds

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  • IPEN-DOC 27408

    SILVA, L.S.V.; MANSANI, G.L.; YOSHIKAWA, D.S. ; CASINI, J.C.S.; FARIA, R.N. . Influence of the electrolyte potential window on the electrical characteristics of supercapacitors operating elevated temperatures. Materials Science Forum, v. 1012, p. 147-152, 2020. DOI: 10.4028/www.scientific.net/MSF.1012.147

    Abstract: The equivalent series resistances (ESR) and specific capacitances (Cs) of supercapacitors carbon electrodes have been investigated using cyclic voltammetry and electrochemical impedance spectroscopy. Commercial activated carbon electrodes employing organic electrolyte have been tested using a potential window in the range of 2.7–3.8 V. Specific capacitances were calculated from cyclic voltammetry curves at room temperature employing various scan rates (30 and 100mVs-1). Internal series resistances of the supercapacitors were measured using the galvanostatic curves at room temperature and above (25 and 50°C). The ESR increase to 9.8 Ω at 25° and 2.7V to 78.8 Ω at with operating temperature raise and also with overpotential. A compositional and morphological evaluation of these electrodes showed a very homogeneous structure. It has been shown that the specific capacitance decreased considerably with scan rate, current density, electrochemical potential window and working temperature.

    Palavras-Chave: capacitive energy storage equipment; electrochemistry; capacitance; equivalent circuits; energy storage; impedance; spectroscopy

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  • IPEN-DOC 27407

    SILVA, D.V. ; GALDINO, G.S. ; BARBOSA, L.P. ; CASINI, J.C.S. ; FARIA, R.N. . Influence of separator thickness on the performance of electric double layer supercapacitors in aqueous electrolyte. Materials Science Forum, v. 1012, p. 109-113, 2020. DOI: 10.4028/www.scientific.net/MSF.1012.109

    Abstract: The effects of the separator thickness (δ) upon the equivalent series resistances (ESR) and specific capacitances (Cs) of supercapacitors electrodes have been investigated using commercially available porous filter paper (δ=150 μm, pores size=7.5 μm, 80 gm-2). Commercial activated carbon electrodes immersed in 1molL-1 KOH electrolyte (25°C) have been employed in this study. The specific capacitances were calculated from cyclic voltammetry curves at room temperature employing various scan rates (5, 10, 15 and 30 mVs-1). Internal series resistances of the supercapacitors were measured using the galvanostatic charge discharge curves also at room temperature. A maximum of 28 separators (δ=4200 μm) have been employed in this investigation. It has been shown that the ESR increases substantially with separator thickness (from 3.1 to 7.9 Ωcm2). The specific capacitance decreased somewhat with increasing separator thickness and scan rates (from 64 to 52 Fg-1; at 5 mVs-1). The microstructures of the electrode material have been investigated using scanning electron microscopy (SEM) and chemical microanalyses employing energy dispersive X-ray analysis (EDX). A compositional and morphological evaluation of these electrodes showed a very homogeneous microstructure.

    Palavras-Chave: capacitive energy storage equipment; capacitors; microstructure; equivalent circuits; energy storage; aqueous solutions; electrolytes; capacitance

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  • IPEN-DOC 27406

    PIERETTI, EURICO F. ; LEIVAS, TOMAZ P.; PILLIS, MARINA F. ; NEVES, MAURICIO D.M. . Failure analysis of metallic orthopedic implant for total knee replacement. Materials Science Forum, v. 1012, p. 471-476, 2020. DOI: 10.4028/www.scientific.net/MSF.1012.471

    Abstract: Fractures resulting from wear and fatigue process have been identified as the main causes of failure in biomaterials, especially in implants that act in place of bone or other hard tissue, as they are subject to conditions involving severe cyclic loadings. In biomaterialscase, the types of failures mentioned above must also be evaluated under the effect of degradation or corrosion, due to the direct contact with body fluids. The present research analyzed the fatigue induced by corrosion fracture of an orthopaedic implant for total knee replacementproduced with an austenitic ASTM F138 stainless steel. The morphology, compositions of the interfaces and subsequent corrosive pitting were characterized by stereoscopy and scanning electron microscopy (SEM) coupled with energy dispersive spectroscopy (EDS). Stress concentration, inclusions and high carbon levels were the main reasons of failure.

    Palavras-Chave: biological materials; implants; metals; bone joints; prostheses; fractures; bone fractures; decomposition; stainless steels; chemical composition

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  • IPEN-DOC 27405

    FANTIN, L.B. ; YOSHIKAWA, D.S. ; GALEGO, E. ; FARIA, R.N. . Effects of electrolyte substitution on the specific capacitance and equivalent series resistance of energy storage electrochemical supercapacitors. Materials Science Forum, v. 1012, p. 131-135, 2020. DOI: 10.4028/www.scientific.net/MSF.1012.131

    Abstract: The microstructure, chemical composition, equivalent series resistance (ESR) and specific capacitance (Cs) of supercapacitors electrodes have been investigated. Commercial activated carbon electrodes employing organic electrolyte have been tested at a potential window of 1.1 and 2.7 V. Specific capacitances were calculated from cyclic voltammetry curves at room temperature employing various scan rates (2-70 mVs-1). Internal resistances of the supercapacitors were calculated using the galvanostatic cycling curves at several current densities (10-175 mAg-1). A maximum specific capacity of 58 Fg-1 has been achieved with the organic electrolyte at a current density of 30 mAg-1 and a potential window of 2.7V. After this initial study, the organic electrolyte was removed from the electrodes by back pumping vacuum. Two new aqueous electrolytes have been substituted in the commercial electrodes for a comparison: Na2SO4 and KOH (1.0 mol.L-1). At a discharge density of 75 mAg-1, the electrodes with KOH showed a maximum specific capacitance of 53 Fg-1 whereas the Na2SO4 showed only 6 Fg-1. ESR of the electrodes with organic electrolyte and KOH were in the range of 20 Ωcm2 whereas with Na2SO4 of 14 Ωcm2. The microstructures of the electrode material have been investigated using scanning electron microscopy (SEM) and chemical microanalyses employing energy dispersive X-ray analysis (EDX). A compositional and morphological evaluation of these electrodes showed a very homogeneous structure.

    Palavras-Chave: microstructure; capacitive energy storage equipment; electrochemistry; capacitance; equivalent circuits; energy storage; activated carbon; electrodes

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  • IPEN-DOC 27404

    MARANHAO, W.C.A. ; ICHIKAWA, R.U. ; TURRILLAS, X.; YOSHITO, W.K. ; SAEKI, M.J.; ORLANDO, M.T.D.; MARTINEZ, L.G. . Characterization of nanostructured Mn-Zn ferrites synthesized by coprecipitation method using CTAB. Materials Science Forum, v. 1012, p. 207-211, 2020. DOI: 10.4028/www.scientific.net/MSF.1012.207

    Abstract: In this work it was investigated the influence of CTAB surfactant concentration on the synthesis of the compound Mn0.75Zn0.25Fe2O4 by the coprecipitation method. It was also compared the influence of hydrothermal treatment on the synthesized materials. The magnetic properties were characterized by AC susceptometry for the determination of the magnetic susceptibility and magnetic density energy. The phases, crystal structure and morphology of the nanoferrites were determined by Rietveld analysis of X-ray diffraction data. It was found the presence of two phases: Franklinite and Akaganeite and it was shown that the samples synthesized only by coprecipitation presented the tendency to increasing the crystallite sizes of the akaganeite phase and decreasing of crystallite sizes of the Franklinite phase as a function of CTAB concentration. The samples submitted to subsequent hydrothermal treatment presented a tendency to decreasing the crystallite sizes of both phases and increasing in Franklinite phase fraction, compared to the samples synthesized only by coprecipitation, suggesting that the hydrothermal treatment was effective in obtaining nanostructured materials of smaller particles.

    Palavras-Chave: ferrites; manganese; zinc; nanostructures; manganese carbides; zinc oxides; coprecipitation; hydrothermal synthesis; x-ray diffraction; calculation methods

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  • IPEN-DOC 27403

    OLIVEIRA, LOUISE F.R. ; NEVES, MAURICIO D.M. das ; ORTEGA, FERNANDO dos S.. AISI 310 stainless steel formed by gelcasting: an alternative manufacturing method. Materials Science Forum, v. 1012, p. 325-330, 2020. DOI: 10.4028/www.scientific.net/MSF.1012.325

    Abstract: This work evaluates the microstructure and the yield strength under compression at room temperature and at 800°C of specimens prepared with AISI 310 stainless steel powder (D50 = 10 μm), manufactured by gelcasting. Parts were vacuum sintered in a single batch at 1280°C. At room temperature, specimens presented average yield strength of 270 MPa, and at 800°C, 105 MPa. Microstructure analysis involved the measurement of grain size along the vertical axis of cylindrical specimens, with special attention to the effect of particles settling, and was conducted using scanning electron and optical microscopy, and X-ray diffraction. Settling effect was assessed considering the position where the specimen was taken and was negligible: both density and yield strength did not vary significantly along the vertical axis.

    Palavras-Chave: microstructure; casting; stainless steels; stainless steel-310; powder metallurgy; yield strength; polymerization

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  • IPEN-DOC 27402

    ARAUJO, JOAO V. de S. ; SILVA, REJANE M.P. da ; DONATUS, UYIME ; MACHADO, CARULINE de S.C. ; COSTA, ISOLDA . Microstructural, electrochemical and localized corrosion characterization of the AA2198-T851 alloy. Materials Research, v. 23, n. 4, p. 1-10, 2020. DOI: 10.1590/1980-5373-MR-2020-0161

    Abstract: In the present work, the microstructure, electrochemical behavior and localized corrosion of the AA2198-T851 Al-Cu-Li alloy were studied. The microstructure was correlated with corrosion results obtained by immersion, gel visualization and scanning electrochemical microscopy (SECM) tests. Immersion and gel visualization tests showed high kinetics of corrosion attack during the first hours of immersion. SECM analyzes by means of surface generation/tip collection (SG/TC) mode detected hydrogen evolution generated during spontaneous corrosion from severe localized corrosion (SLC) sites on the metal surface. SECM results revealed sites of intense hydrogen evolution after 2 h of immersion and increased amounts of corrosion products after 4 h of immersion. Hydrogen evolution sites detected by SECM were associated with severe localized corrosion (SLC).

    Palavras-Chave: microstructure; corrosion; aluminium alloys; hydrogen; electrochemistry; scanning electron microscopy; copper alloys; lithium alloys; gels; data visualization

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  • IPEN-DOC 27401

    ALENCAR, CATARINE S.L. ; PAIVA, ANA R.N. ; SILVA, JULIO C.M. da ; VAZ, JORGE M. ; SPINACE, ESTEVAM V. . One-step synthesis of AuCu/TiO2 catalysts for CO preferential oxidation. Materials Research, v. 23, n. 5, p. 1-6, 2020. DOI: 10.1590/1980-5373-MR-2020-0181

    Abstract: Au/TiO2 (1wt% Au), Cu/TiO2 (1wt% Cu) and AuCu/TiO2 (1wt% AuCu) catalysts with different Au:Cu mass ratios were prepared in one-step synthesis using sodium borohydride as reducing agent. The resulting catalysts were characterized by X-ray diffraction (XRD), X-ray Dispersive Energy (EDX), Transmission Electron Microscopy (TEM) and Temperature Programmed Reduction (TPR) and tested for the preferential oxidation of carbon monoxide (CO-PROX reaction) in H2-rich gases. EDS analysis showed that the Au contents are close to the nominal values whereas for Cu these values are always lower. X-ray diffractograms showed only the peaks of TiO2 phase; no peaks of metallic Au and Cu species or oxides phases were observed. TPR and high-resolution TEM analysis showed that AuCu/TiO2 catalysts exhibited most of Au in the metallic form with particles sizes in the range of 3-5 nm and that Cu was found in the form of oxide in close contact with the Au nanoparticles and well spread over the TiO2 surface. The AuCu/TiO2 catalysts exhibited good performance in the range of 75-100 °C and presented a better catalytic activity when compared to the monometallic ones. A maximum CO conversion of 98.4% with a CO2 selectivity of 47% was obtained for Au0.50Cu0.50/TiO2 catalyst at 100°C.

    Palavras-Chave: carbon monoxide; catalysts; hydrogen; oxidation; titanium oxides; gold; proton exchange membrane fuel cells; nanoparticles; copper

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  • IPEN-DOC 27400

    ROSERO, WILMMER A.A. ; GUIMARAES, ROBSON R.; MATIAS, TIAGO A.; ARAKI, KOITI. Effect of push-pull ruthenium complex adsorption conformation on the performance of dye sensitized solar cells. Journal of the Brazilian Chemical Society, v. 31, n. 11, p. 2250-2264, 2020. DOI: 10.21577/0103-5053.20200077

    Abstract: A new series of tris-(bipyridyl)ruthenium-like complexes based on the 4-tripheylamine-2,2’:6’,2’’-terpyridine (TPA) push-pull ligand was prepared by incorporation of 4-carboxypyridine (cpy), 4,4’-dicarboxi-2,2’-bipyridine (dcbpy) and 4-carboxyterpyridine ligands (ctpy) ligands, in order to adsorb them on TiO2 in different anchoring conformations. The electron photoinjection and electron recombination processes of the respective dye-sensitized solar cells were greatly influenced by the molecular structure, which defined the surface concentration and surface charge on TiO2, such that the photoconversion efficiency was 10 times larger for [Ru(py)(dcbpy)(TPAtpy)] than for the [Ru(cpy)(bpy)(TPAtpy)](PF6) dye. Molecules anchoring in a more upright position and by a larger number of sites were shown to enhance the electron injection into TiO2 conduction band (CB) improving the short-circuit current (JSC), open circuit voltage (Voc) and the overall photoconversion efficiency. However, a positive net charge in the dye increased the back electron-transfer reactions and induced a decrease in both Voc and conversion efficiency.

    Palavras-Chave: ruthenium; dyes; titanium oxides; films; photoelectrochemical cells; solar cells; photosensitivity; adsorption

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  • IPEN-DOC 27399

    GAIOLLO, EDSON L. ; MOREIRA, RENAN P. ; FELINTO, MARIA C.F.C. ; BARBOSA, HELLIOMAR P.; PEDROSO, CASSIO C.S.; TEOTONIO, ERCULES E.S.; MALTA, OSCAR L.; BRITO, HERMI F.. Blue-emitting MWO4:Tm3+ (M: Sr, Ba) phosphors prepared by coprecipitation method at room temperature. Journal of the Brazilian Chemical Society, v. 31, n. 11, p. 2430-2438, 2020. DOI: 10.21577/0103-5053.20200191

    Abstract: MWO4 host matrices (M: Sr, Ba) doped with different Tm3+ concentrations (0.02, 0.04, 0.06, 0.08 and 0.10 mol%) have been successfully prepared by the coprecipitation method at room temperature. The as-prepared nanophosphors were characterized by infrared spectroscopy showing intense absorption bands in the range of 700-1000 cm-1 attributed to the symmetrical and asymmetrical stretching vibrations (ν) of the tetrahedral [WO4]2- group. The X-ray diffraction (XRD) measurements reveal the tetragonal scheelite phase with the I41/a (No. 88) space group. The emission spectra of the MWO4:Tm3+ materials are dominated by the highest intensity narrow band of the intraconfigurational 1D2 → 3F4 transitions in the blue region (ca. 456 nm) arising from the Tm3+ ions. Additional low-intensity emission bands originated from the 1G4 → 3H6 (ca. 475 nm), 1G4 → 3F4 (660 nm) and 3H4 → 3H6 (700 nm) transitions are also observed. These optical results indicate that the materials can be used as an alternative to blue-emitting markers.

    Palavras-Chave: thulium; strontium compounds; tungstates; coprecipitation; photoluminescence; barium

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  • IPEN-DOC 27398

    ZAPATA, S.; PATINO, A.; CARDONA, A.; PARRA, M.; VALENCIA, V.; REINERS, P.; OBOH-ILKUENOBE, F.; GENEZINI, F. . Bedrock and detrital zircon thermochronology to unravel exhumation histories of accreted tectonic blocks: an example from the Western Colombian Andes. Journal of South American Earth Sciences, v. 103, p. 1-15, 2020. DOI: 10.1016/j.jsames.2020.102715

    Abstract: The Northern Andes are the result of multiple tectonic phases, which include extensional and compressional volcanic arcs, strike-slip fragmentation, and accretion of exotic terranes. The alternations of these tectonic settings have overprinted and fragmented the geological record, which has hindered precise paleogeographic and tectonic reconstructions. In the western segment of the Colombian Andes, the oceanic-cored Western Cordillera (WC) and the continental Central Cordillera (CC) are separated by the Romeral Fault Zone (RFZ). This segment of the Andes preserves the record of Cretaceous back-arc extension, the onset of compression, and the accretion of the Caribbean plateau during the Late Cretaceous-Paleocene. To refine the tectonic evolution of the Western Colombian Andes, this study documents new detrital zircon fission-track (ZFT) data from the Meso-Cenozoic sedimentary cover in the CC, the RFZ, and the WC; new ZFT and zircon helium (ZHe) bedrock data from the CC and the RFZ; and new U–Pb detrital data from the Miocene sedimentary cover of the RFZ. Within the RFZ, we obtained bedrock ZFT ages of 239.0 ± 11.0 Ma and 111.1 ± 4.3 Ma, and detrital ZFT data from the Abejorral Formation are interpreted as the result of post-magmatic cooling and Cretaceous rifting. Late Cretaceous to Eocene ZFT and ZHe ages (~61–50 Ma) in the CC and detrital ZFT data in the WC record exhumation and deformation of the CC during and after the collision of the Caribbean plateau with the continental margin. Finally, detrital U–Pb and ZFT data from the Amagá Formation record the formation of a Miocene intermountain basin. This study reconstructs the basin geometries and the deformation patterns before, during, and after the collision of the Caribbean plateau with the South American margin. We highlight that in accretionary orogens, in which prolonged deformation and erosion have removed the sedimentary cover, the quantification of differential basement exhumation is key to reconstruct thick-skin deformation and to define major tectonic boundaries.

    Palavras-Chave: tectonics; rocks; sedimentary rocks; geologic ages; age estimation; archaeology; zircon

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  • IPEN-DOC 27397

    PRADO, EDUARDO S.P.; MIRANDA, FELIPE S.; ARAUJO, LEANDRO G. de ; PETRACONI, GILBERTO; BALDAN, MAURICIO R.. Thermal plasma technology for radioactive waste treatment: a review. Journal of Radioanalytical and Nuclear Chemistry, v. 325, n. 2, p. 331-342, 2020. DOI: 10.1007/s10967-020-07269-4

    Abstract: In this paper, a review of radioactive wastes treatment using thermal plasma technology is presented as a treatment method for radioactive waste management.Virtually all waste streams can be treated by the thermal plasma technologies, resulting in a conditioned product, free from organics and liquids, definitely meeting the acceptance criteria for safe storage and disposal. The application of the thermal plasma system in the nuclear area is still one of the current research topics due to the theoretical and practical complexity of the treatment. This paper discusses the performance of the thermal plasma systems, addressing the advantages and limitations of the method.

    Palavras-Chave: plasma technology; radioactive waste management; radioactive waste processing; management; processing

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  • IPEN-DOC 27396

    WAKASUGI, DENISE S.M. ; DAMATTO, SANDRA R. ; ULRICH, JOAO C. . Natural radionuclides 226Ra, 228Ra, 210Pb and 210Po and inorganic chemical elements determined in mineral waters from Águas de Contendas and Lambari, Brazil. Journal of Radioanalytical and Nuclear Chemistry, v. 326, n. 1, p. 51-63, 2020. DOI: 10.1007/s10967-020-07357-5

    Abstract: Natural radionuclides 226Ra, 228Ra, 210Pb and 210Po activity concentrations and the inorganic chemical composition were determined in radioactive mineral water springs from the Water Parks of Águas de Contendas and Lambari, located in the Water Circuit of the state of Minas Gerais, Brazil. Radionuclides were determined by gross alpha and beta measurements and alpha spectrometry, and the chemical elements by ICP-OES. Among the radionuclides analyzed, the highest activity concentrations obtained were for 226Ra and 228Ra and the chemical elements Ca, Fe and Na presented higher values of concentrations. Pearson’s correlation coefficient analysis was performed to verify the correlation between natural radionuclides and the chemical elements.

    Palavras-Chave: radioisotopes; chemical composition; alpha spectroscopy; radium 226; radium 228; lead 210; polonium 210; chemical analysis; elements; water; ground water

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  • IPEN-DOC 27395

    COME, BENEDETTA; DONATO, MARESSA ; POTENZA, LUCIA F.; MARIANI, PAOLO; ITRI, ROSANGELA; SPINOZZI, FRANCESCO. The intriguing role of rhamnolipids on plasma membrane remodelling: from lipid rafts to membrane budding. Journal of Colloid and Interface Science, v. 582, n. Part B, p. 669-677, 2021. DOI: 10.1016/j.jcis.2020.08.027

    Abstract: Rhamnolipids (RLs) comprise a class of glycolipids produced by Pseudomonas aeruginosa under appropriate culture medium. They act as biosurfactants being composed by a hydrophilic head of either one (mono-RL) or two (di-RL) rhamnose moieties coupled to hydroxyaliphatic chains. It is well accepted that RLs present low biolitic activity as compared to other synthetic surfactants. However, their mechanisms of action in biological systems are not well defined yet. The interaction of RLs with lipid bilayers are here investigated to address how they impact on plasma membrane at molecular level. Our experimental approach was based on a deep analysis of optical microscopy data from giant unilamellar vesicles (GUVs) dispersed in aqueous solutions containing up to 0.5 mM of commercially available RLs (a mixture of mono-RL, 33–37 mol%, and di-RL, 63–67 mol%, cmc of 0:068 ± 0:005 mM). GUVs were made up of a single lipid POPC and a ternary system containing DOPC, sphingomyelin and cholesterol, which mimic lipid raft platforms. Our results demonstrate that RLs have a low partition in the lipid bilayer in respect to the total molecules in solution. We suppose that RLs insert in the outer leaflet with low propensity to flip-flop. In the case of POPC GUVs, the insertion of RL molecules in the outer leaflet impairs changes in spontaneous membrane curvature with incubation time. Then, small buds are formed that remain linked to the original membrane. No changes in membrane permeability have been detected. A remarkable result refers to the insertion of RLs in membranes containing liquid ordered (Lo) - liquid disordered (Ld) phase coexistence. The rate of interaction has been observed to be higher for Ld phase than for Lo phase (0:12 . 10-6 s-1 and 0:023 . 10-6 s-1 for Ld and Lo, respectively, at RL concentration of 0.5 mM). As a consequence, the preferential RL insertion in Ld phase may also alter the membrane spontaneous curvature which, coupled to the change in the line tension associated to the domains boundary, conducted to Lo domain protrusion. Even if it has been observed on a model system, such membrane remodelling might correlate to endocytic processes activated in cell membranes, regardless of the participation of specific proteins. Further, changes imposed by RLs in lipid rafts may affect the association of key proteins enrolled in cell signaling, which may perturb cell homeostasis.

    Palavras-Chave: membranes; lipids; cell membranes; microorganisms; plasma; pseudomonas; surfactants

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  • IPEN-DOC 27394

    SABINO, CAETANO P.; BALL, ANTHONY R.; BAPTISTA, MAURICIO S.; DAI, TIANHONG; HAMBLIN, MICHAEL R.; RIBEIRO, MARTHA S. ; SANTOS, ANA L.; SELLERA, FABIO P.; TEGOS, GEORGE P.; WAINWRIGHT, MARK. Light-based technologies for management of COVID-19 pandemic crisis. Journal of Photochemistry and Photobiology B: Biology, v. 212, p. 1-8, 2020. DOI: 10.1016/j.jphotobiol.2020.111999

    Abstract: The global dissemination of the novel coronavirus disease (COVID-19) has accelerated the need for the implementation of effective antimicrobial strategies to target the causative agent SARS-CoV-2. Light-based technologies have a demonstrable broad range of activity over standard chemotherapeutic antimicrobials and conventional disinfectants, negligible emergence of resistance, and the capability to modulate the host immune response. This perspective article identifies the benefits, challenges, and pitfalls of repurposing light-based strategies to combat the emergence of COVID-19 pandemic.

    Palavras-Chave: visible radiation; coronaviruses; ultraviolet radiation; antimicrobial agents; inactivation; photosensitivity; modulation; radiobiology; epidemiology; lasers; viruses

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  • IPEN-DOC 27393

    TOLEDO, VICTOR H.; YOSHIMURA, TANIA M. ; PEREIRA, SAULO T. ; CASTRO, CARLOS E.; FERREIRA, FABIO F.; RIBEIRO, MARTHA S. ; HADDAD, PAULA S.. Methylene blue-covered superparamagnetic iron oxide nanoparticles combined with red light as a novel platform to fight non-local bacterial infections: a proof of concept study against Escherichia coli. Journal of Photochemistry and Photobiology B: Biology, v. 209, p. 1-10, 2020. DOI: 10.1016/j.jphotobiol.2020.111956

    Abstract: Currently, antimicrobial photodynamic therapy (APDT) is limited to the local treatment of topical infections, and a platform that can deliver the photosensitizer to internal organs is highly desirable for non-local ones; SPIONs can be promising vehicles for the photosensitizer. This work reports an innovative application of methylene blue (MB)-superparamagnetic iron oxide nanoparticles (SPIONs). We report on the preparation, characterization, and application of MB-SPIONs for antimicrobial photodynamic therapy. When exposed to light, the MB photosensitizer generates reactive oxygen species (ROS), which cause irreversible damage in microbial cells. We prepare SPIONs by the co-precipitation method. We cover the nanoparticles with a double silica layer – tetraethyl orthosilicate and sodium silicate – leading to the hybrid material magnetite-silica-MB. We characterize the as-prepared SPIONs by Fourier transform infrared spectroscopy, powder X-ray diffraction, and magnetic measurements. We confirm the formation of magnetite using powder X-ray diffraction data. We use the Rietveld method to calculate the average crystallite size of magnetite as being 14 nm. Infrared spectra show characteristic bands of iron‑oxygen as well as others associated with silicate groups. At room temperature, the nanocomposites present magnetic behavior due to the magnetite core. Besides, magnetite-silica-MB can promote ROS formation. Thus, we evaluate the photodynamic activity of Fe3O4-silica-MB on Escherichia coli. Our results show the bacteria are completely eradicated following photodynamic treatment depending on the MB release time from SPIONs and energy dose. These findings encourage us to explore the use of magnetite-silica-MB to fight internal infections in preclinical assays.

    Palavras-Chave: antimicrobial agents; therapy; methylene blue; silica; iron oxides; superparamagnetism; escherichia coli; magnetite; photosensitivity; reactivity; oxygen

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  • IPEN-DOC 27392

    KODALI, DEEPA; UDDIN, MD-JAMAL; MOURA, ESPERIDIANA A.B. ; RANGARI, VIJAK K.. Mechanical and thermal properties of modified Georgian and Brazilian clay infused biobased epoxy nanocomposites. Materials Chemistry and Physics, v. 257, 2021. DOI: 10.1016/j.matchemphys.2020.123821

    Abstract: This study focuses on the preparation and characterization of nanocomposite system with bio-based epoxy resin (Super SAP 100/1000, contains 37% bio-based carbon content) and natural clays including Georgian clay and Brazilian clay. Georgian clay was surface modified using an ultrasound processing in presence of Decalin. Brazilian clay was modified to organophilic bentonite using quaternary ammonium salts. The resulting nano clay particles were characterized using XRD and TEM to confirm the particle size reduction and uniform distribution. The as-fabricated nanocomposites were characterized using flexure, DMA, TMA and TGA. The flexure analysis showed that the modified clay composites have significant improvement in strength (23–38%) and modulus (28–37%). Delayed thermal degradation was observed from TGA analysis which showed that the major degradation temperatures improved from 7°-25°C. DMA and TMA analysis showed improvements in storage moduli (4–6%) and coefficient of thermal expansion (CTE) (6–64%), respectively. The notable improvement in thermal and mechanical properties suggested the effective dispersion and the high degree of polymer particle interaction. The bio based content present in the Super Sap 100/1000 acts as plasticizer resulting in the extensive ductility of the polymer.

    Palavras-Chave: nanocomposites; epoxides; clays; mechanical properties; thermal degradation; bentonite; thermomechanical treatments; differential thermal analysis; calorimetry

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  • IPEN-DOC 27391

    MILAGRE, MARIANA X. ; DONATUS, UYIME; SILVA, REJANE M.P. ; BETANCOR-ABREU, ABENCHARA M.; RAMIREZ, OSCAR M.P.; MACHADO, CARULINE S.C. ; ARAUJO, JOAO V.S. ; SOUTO, RICARDO M.; COSTA, ISOLDA . Galvanic coupling effects on the corrosion behavior of the 6061 aluminum alloy used in research nuclear reactors. Journal of Nuclear Materials, v. 541, p. 1-11, 2020. DOI: 10.1016/j.jnucmat.2020.152440

    Abstract: The 6061 alloy is used in different thermomechanical conditions in research nuclear reactors. Nuclear fuel plates are manufactured by the picture frame technique (PFT) and the 6061 alloy is used as cladding for the nuclear fuel “sandwiches”. After the PFT process, these nuclear plates are placed in a case made of 6061-T6 alloy. In this work, the galvanic effects of coupling the 6061 alloy in the T6 and PFT temper conditions were investigated in different chloride-containing solutions. The results showed that galvanic coupling was favored between the PFT and 6061-T6 alloy. A potential difference of about 50 mV was observed between the temper conditions. This was attributed to differences in β’’ phase density between the two conditions (T6 and PFT) which was indicated by microhardness results. The 6061 alloy in the PFT condition was cathodic in relation to the T6 one. Results from conventional electrochemical techniques were in agreement with the local measurements. Local electrochemical techniques such as the SVET, SECM and LEIS were useful in characterizing the electrochemical behavior of the galvanically coupled alloys.

    Palavras-Chave: corrosion; electrochemical corrosion; aluminium alloys; electrochemistry; scanning electron microscopy; research reactors; reactors; nuclear fuels

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  • IPEN-DOC 27390

    MILAGRE, MARIANA X. ; DONATUS, UYIME; MOGILI, NAGA V.; MACHADO, CARULINE S.C. ; ARAUJO, JOAO V.S. ; KLUMPP, RAFAEL E. ; FERNANDES, STELA M.C. ; SOUZA, JOSE A.B. de ; COSTA, ISOLDA . Effects of Picture Frame Technique (PFT) on the corrosion behavior of 6061 aluminum alloy. Journal of Nuclear Materials, v. 539, p. 1-13, 2020. DOI: 10.1016/j.jnucmat.2020.152320

    Abstract: The 6061 Al–Mg–Si alloy is used in nuclear fuel plates of nuclear research reactors which are fed with fuel in plate shapes. The production of these plates is based on the picture frame technique (PFT). The picture frame technique (PFT) is a manufacturing process for the fabrication of nuclear fuel plates where the nuclear fuel is encapsulated by Al alloy plates and thermomechanically processed to generate a set with reduced thickness. The effects of PFT on the corrosion resistance of the 6061 aluminum alloy were evaluated in this study by immersion and electrochemical tests in 0.005 mol L−1 NaCl solution. The results showed that the PFT fabrication process increases the corrosion resistance of the 6061 alloy in relation to the conventional 6061-T6, due phase dissolution and lower content of β’’ phase. Also, corrosion propagation gradually changes, with an increasing number of processing steps, from intergranular to intragranular corrosion attack.

    Palavras-Chave: aluminium alloys; corrosion; fuel elements; pitting corrosion; differential thermal analysis; magnesium; silica; fuel plates

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  • IPEN-DOC 27389

    OLIVEIRA, RODRIGO K. de; CORREA, OLANDIR V. ; OLIVEIRA, MARA C.L. de; ANTUNES, RENATO A.. Surface chemistry and semiconducting properties of passive film and corrosion resistance of annealed surgical stainless steel. Journal of Materials Engineering and Performance, v. 29, n. 9, p. 6085-6100, 2020. DOI: 10.1007/s11665-020-05067-3

    Abstract: ASTM F-139 surgical stainless steel was subjected to annealing treatments at 700 °C for different times. The effect of annealing on the chemical composition of the passive film was evaluated by x-ray photoelectron spectroscopy. The correlation of the surface chemistry with the corrosion behavior and semiconducting properties of the passive film was also investigated. Potentiodynamic polarization tests were conducted in phosphate-buffered solution at 37°C. The semiconducting character of the passive film was assessed by the Mott–Schottky approach. The microstructure of the annealed samples was characterized by optical microscopy. The grain size increased after annealing, but the differences between each annealing condition were not significant and could not be associated with the corrosion behavior of the annealed samples. The corrosion resistance was improved depending on the heat treatment condition due to compositional changes of the passive film upon annealing. The best corrosion properties were observed after annealing for 8 h which was ascribed to Cr2O3, MoO3 and FeO enrichment in the passive film.

    Palavras-Chave: annealing; heat treatments; corrosion; schottky barrier diodes; surfaces; chemistry; austenitic steels; stainless steels; surfaces; chemistry; microstructure

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  • IPEN-DOC 27388

    ALI, BAKHAT; STEFANI, HELIO A.; IMRAN, MUHAMMAD; IRFAN, AHMAD; ASSIRI, MOHAMMED A.; FELINTO, MARIA C.F.C. ; KHALID, MUHAMMAD; AL-SEHEMI, ABDULLAH G.. Synthesis, structure study, first-principles investigations and luminescence properties of europium and terbium complexes. Journal of Fluorescence, v. 30, n. 6, p. 1345-1355, 2020. DOI: 10.1007/s10895-020-02613-z

    Abstract: The synthesis of 1-benzyl-2-((2-Aminoethyl) amino)-5-oxopyrrolidine-3,4-diyl diacetate (boad), an oxopyrrolidine type ligand; designed to coordinate lanthanides (Eu3+ and Tb3+) to get luminescent material. The target complexes showed good photoluminescence properties, which indicate that this type of compound can be used as sensitizers having luminescence for the green (Tb3+) and red (Eu3+) emission. The obtained results revealed that sensitizer efficiency can be improved by adding ligands like acac (Eu(acac)3, which has also enhanced the luminescence quantum output and period for Eu3+ ions. The ground state geometries were developed by using density functional theory at B3LYP/6-31G** level. The charge transfer analysis and electronic properties were performed. The Europium and Terbium complexes formation with boad ligand was explored based on molecular electrostatic potential, MDC-q charges, and frontier molecular orbitals (FMOs) analysis.

    Palavras-Chave: synthesis; europium complexes; terbium complexes; luminescence; tartaric acid; pyrrolidines; rare earths; photoluminescence; density functional method; nmr spectra

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  • IPEN-DOC 27387

    ARAUJO, LEANDRO G. de ; BORBA, TANIA R. de ; FERREIRA, RAFAEL V. de P.; CANEVESI, RAFAEL L.S.; SILVA, EDSON A. da; DELLAMANO, JOSE C. ; MARUMO, JULIO T. . Use of calcium alginate beads and Saccharomyces cerevisiae for biosorption of 241Am. Journal of Environmental Radioactivity, v. 223-224, p. 1-10, 2020. DOI: 10.1016/j.jenvrad.2020.106399

    Abstract: Calcium alginate beads, inactivated Saccharomyces cerevisiae and inactivated S. cerevisiae immobilized in calcium alginate beads (S. cerevisiae–calcium alginate beads) are examined as potential biosorption materials as regards their capacity to remove 241Am. In this study, initial experiments were carried out to evaluate the effects of pH (2 and 4) and 241Am initial concentration: 75, 150, and 300 Bq mL-1. The experiments were conducted in a batch reactor. Higher removal capacity was observed at pH 2 with the use of S. Cerevisiae, whereas pH 4 performed better for the essays with calcium alginate beads and S. Cerevisiae-calcium alginate beads. The pseudo-first-order kinetic model described the kinetics of biosorption. Calcium alginate was the adsorbent of choice to further experiments with synthetic organic liquid waste. A lower removal rate was observed in the organic waste, although calcium alginate beads have also been able to achieve high sorption capacity in less than 4 h. With the organic waste, the highest value of sorption capacity of 241Am was 4.38 × 10−7 mmol g−1 with an initial 241Am concentration of 2.31 × 10−8 mmol L−1.

    Palavras-Chave: bioadsorbents; sorption; adsorbents; americium 241; saccharomyces cerevisiae; calcium; alginates; ph value

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  • IPEN-DOC 27386

    RIGHI, HENRIETTE; ARRUDA-NETO, JOAO D.T.; GOMEZ, JOSE G.C.; SILVA, LUIZIANA F. da; SOMESSARI, ELIZABETH S.R. ; LEMOS, ALINE C.C.. Exposure of Deinococcus radiodurans to both static magnetic fields and gamma radiation: observation of cell recuperation effects. Journal of Biological Physics, v. 46, n. 3, p. 309-324, 2020. DOI: 10.1007/s10867-020-09554-5

    Abstract: The extremophilic bacterium Deinococcus radiodurans displays an extraordinary ability to withstand lethal radiation effects, due to its complex mechanisms for both proteome radiation protection and DNA repair. Published results obtained recently at this laboratory show that D. radiodurans submitted to ionizing radiation results in its DNA being shattered into small fragments which, when exposed to a “static electric field’ (SEF), greatly decreases cell viability. These findings motivated the performing of D. radiodurans exposed to gamma radiation, yet exposed to a different exogenous physical agent, “static magnetic fields” (SMF). Cells of D. radiodurans [strain D.r. GY 9613 (R1)] in the exponential phase were submitted to 60Co gamma radiation from a gamma cell. Samples were exposed to doses in the interval 0.5–12.5 kGy, while the control samples were kept next to the irradiation setup. Exposures to SMF were carried out with intensities of 0.08 T and 0.8 T delivered by two settings: (a) a device built up at this laboratory with niobium magnets, delivering 0.08 T, and (b) an electromagnet (Walker Scientific) generating static magnetic fields with intensities from 0.1 to 0.8 T. All samples were placed in a bacteriological incubator at 30 °C for 48 h, and after incubation, a counting of colony forming units was performed. Two sets of cell surviving data were measured, each in triplicate, obtained in independent experiments. A remarkable similarity between the two data sets is revealed, underscoring reproducibility within the 5% range. Appraisal of raw data shows that exposure of irradiated cells to SMF substantially increases their viability. Data interpretation strongly suggests that the increase of D. radiodurans cell viability is a sole magnetic physical effect, driven by a stochastic process, improving the efficiency of the rejoining of DNA fragments, thus increasing cell viability. A type of cut-off dose is identified at 10 kGy, above which the irradiated cellular system loses recovery and the cell survival mechanism collapses.

    Palavras-Chave: gamma radiation; micrococcus radiodurans; bacteria; ionizing radiations; survival curves; magnetic fields; dna

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  • IPEN-DOC 27385

    MAZIERO, JOANA S. ; THIPE, VELAPHI C. ; ROGERO, SIZUE O. ; CAVALCANTE, ADRIANA K. ; DAMASCENO, KELME C. ; ORMENIO, MATHEUS B. ; MARTINI, GISELA A. ; BATISTA, JORGE G.S. ; VIVEIROS, WILLIAM; KATTI, KAVITA K.; KARIKACHERY, ALICE R.; MOHANDOSS, DARSHAKUMAR D.; DHURVAS, RASHMI D.; NAPPINNAI, MOHANAVELU; ROGERO, JOSE R. ; LUGAO, ADEMAR B. ; KATTI, KATTESH V.. Species-specific in vitro and in vivo evaluation of toxicity of silver nanoparticles stabilized with gum arabic protein. International Journal of Nanomedicine, v. 15, p. 7359-7376, 2020. DOI: 10.2147/IJN.S250467

    Abstract: Introduction: We report, herein, in vitro, and in vivo toxicity evaluation of silver nanoparticles stabilized with gum arabic protein (AgNP-GP) in Daphnia similis, Danio rerio embryos and in Sprague Dawley rats. Purpose: The objective of this investigation was to evaluate in vitro and in vivo toxicity of silver nanoparticles stabilized with gum arabic protein (AgNP-GP), in multispecies due to the recognition that toxicity evaluations beyond a single species reflect the environmental realism. In the present study, AgNP-GP was synthesized through the reduction of silver salt using the tri-alanine-phosphine peptide (commonly referred to as “Katti Peptide”) and stabilized using gum arabic protein. Methods: In vitro cytotoxicity tests were performed according to ISO 10993– 5 protocols to assess cytotoxicity index (IC50) values. Acute ecotoxicity (EC50) studies were performed using Daphnia similis, according to the ABNT NBR 15088 protocols. In vivo toxicity also included evaluation of acute embryotoxicity using Danio rerio (zebrafish) embryos following the OECD No. 236 guidelines. We also used Sprague Dawley rats to assess the toxicity of AgNP-GP in doses from 2.5 to 10.0 mg kg− 1 body weight. Results: AgNP-GP nanoparticles were characterized through UV (405 nm), core size (20± 5 nm through TEM), hydrodynamic size (70– 80 nm), Zeta (ζ) potential (- 26 mV) using DLS and Powder X ray diffraction (PXRD) and EDS. PXRD showed pattern consistent with the Ag (1 1 1) peak. EC50 in Daphnia similis was 4.40 (3.59– 5.40) μg L− 1. In the zebrafish species, LC50 was 177 μg L− 1. Oral administration of AgNP-GP in Sprague Dawley rats for a period of 28 days revealed no adverse effects in doses of up to 10.0 mg kg− 1 b.w. in both male and female animals. Conclusion: The non-toxicity of AgNP-GP in rats offers a myriad of applications of AgNP-GP in health and hygiene for use as antibiotics, antimicrobial and antifungal agents.

    Palavras-Chave: nanoparticles; nanotechnology; fishes; antimitotic drugs; toxicity; aquatic organisms; daphnia; rats; gum acacia; in vitro; in vivo

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  • IPEN-DOC 27384

    COUTO, VERONICA M.; OLIVEIRA-NASCIMENTO, LAURA de; CABEÇA, LUIZ F.; GERALDES, DANILO C.; COSTA, JULIANA S.R.; RISKE, KARIN A.; FRANZ-MONTAN, MICHELLE; YOKAYCHIYA, FABIANO ; FRANCO, MARGARETH K.K.D. ; PAULA, ENEIDA de. Capsaicin-cyclodextrin complex enhances mepivacaine targeting and improves local anesthesia in inflamed tissues. International Journal of Molecular Sciences, v. 21, n. 16, p. 1-18, 2020. DOI: 10.3390/ijms21165741

    Abstract: Acidic environments, such as in inflamed tissues, favor the charged form of local anesthetics (LA). Hence, these drugs show less cell permeation and diminished potency. Since the analgesic capsaicin (CAP) triggers opening of the TRPV1 receptor pore, its combination with LAs could result in better uptake and improved anesthesia. We tested the above hypothesis and report here for the first time the analgesia effect of a two-drug combination (LA and CAP) on an inflamed tissue. First, CAP solubility increased up to 20 times with hydroxypropyl-beta-cyclodextrin (HP-β-CD), as shown by the phase solubility study. The resulting complex (HP-β-CD-CAP) showed 1:1 stoichiometry and high association constant, according to phase-solubility diagrams and isothermal titration calorimetry data. The inclusion complex formation was also confirmed and characterized by differential scanning calorimetry (DSC), X-ray diffraction, and 1H-NMR. The freeze-dried complex showed physicochemical stability for at least 12 months. To test in vivo performance, we used a pain model based on mouse paw edema. Results showed that 2% mepivacaine injection failed to anesthetize mice inflamed paw, but its combination with complexed CAP resulted in pain control up to 45 min. These promising results encourages deeper research of CAP as an adjuvant for anesthesia in inflamed tissues and cyclodextrin as a solubilizing agent for targeting molecules in drug delivery.

    Palavras-Chave: anesthesia; inflammation; anesthetics; dextrin; scanning electron microscopy; differential thermal analysis; calorimetry

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  • IPEN-DOC 27383

    RAMOS, A.S. ; SANTOS, M.C.L. ; GODOI, C.M. ; QUEIROZ, L.C. de; NANDENHA, J. ; FONTES, E.H. ; BRITO, W.R.; MACHADO, M.B.; NETO, A.O. ; SOUZA, R.F.B. de . High CO tolerance of Pt nanoparticles synthesized by sodium borohydride in a time-domain NMR spectrometer. International Journal of Hydrogen Energy, v. 45, n. 43, p. 22973-22978, 2020. DOI: 10.1016/j.ijhydene.2020.06.105

    Abstract: The CO poisoning effect was overcome using a novel synthesis method. This method consists of using sodium borohydride reducing agent assisted by magnetic field and radiofrequency pulses in the time-domain NMR spectrometer. This synthesis was useful to disperse the Pt nanoparticles over the carbon support and to compress the lattice strain of the Pt crystalline structure. Besides that, Pt/C MFP90° showed a multi-CO oxidation component in cyclic voltammetry, and this can avoid the poisoning effect by creating a large availability of CO species to be adsorbed, desorbed, and re-adsorbed. Pt/C MFP90° has also shown the best performance in the PEMFC regarding H2 and CO + H2 experiments.

    Palavras-Chave: carbon compounds; carbon monoxide; platinum; carbon; fuel cells; nanoparticles; borohydrides; sodium compounds; nmr spectra; nuclear magnetic resonance

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  • IPEN-DOC 27382

    PERIGO, E.A.; FARIA, R.N. . Temperature dependence of irreversible flux loss field in sintered ferrite magnets: a connection with chemical composition and physical properties. IEEE Magnetics Letters, v. 11, 2020. DOI: 10.1109/LMAG.2020.3028842

    Abstract: This letter discusses the temperature dependence of the magnetic field at which irreversible magnetic flux loss of ferrite sintered magnets is initiated. In this material class such a field might reduce linearly: comparable behavior to that observed for Nd-Fe-B-based sintered counterparts increases linearly or even peaks for temperatures above 350 K. These differences are attributed to variations in the saturation polarization and magnetocrystalline anisotropy constant(s) of the hard-magnetic phase arising from changes in the chemical composition. A comparison between HK and HD5, where the latter is defined in an IEC standard, is also presented and discussed.

    Palavras-Chave: microstructure; ferrites; magnetic materials; hardness; coercive force; magnetic properties; temperature dependence

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  • IPEN-DOC 27381

    PERIGO, E.A.; FARIA, R.N. . Experimental assessment of coercivity microstructural parameters of a Nd-Fe-B sintered magnet. IEEE Magnetics Letters, v. 11, 2020. DOI: 10.1109/LMAG.2020.3029745

    Abstract: We examined the microstructural parameter α in order to investigate the influence of its components on the intrinsic coercivity of an isotropic Nd-Fe-B sintered magnet. By applying boundary conditions for the assessment of grain (mis)alignment αψ and exchange coupling αexc and combining with magnetic measurements and structural characterization results obtained by magnetic small angle neutron scattering, the parameter αK—associated with the reduction of the magnetocrystalline field—plays a major role on the reduction of coercivity of the case study. Approaches in determining〈αK〉are also discussed.

    Palavras-Chave: magnetic materials; magnetic properties; microstructure; coercive force; defects; magnets; neodymium alloys; boron alloys; iron alloys; sintered materials

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  • IPEN-DOC 27380

    MAKHUVELE, RHULANI; NAIDU, KAYLEEN; GBASHI, SEFATER; THIPE, VELAPHI C. ; ADEBO, OLUWAFEMI A.; NJOBEH, PATRICK B.. The use of plant extracts and their phytochemicals for control of toxigenic fungi and mycotoxins. Heliyon, v. 6, n. 10, p. 1-11, 2020. DOI: 10.1016/j.heliyon.2020.e05291

    Abstract: Mycotoxins present a great concern to food safety and security due to their adverse health and socio-economic impacts. The necessity to formulate novel strategies that can mitigate the economic and health effects associated with mycotoxin contamination of food and feed commodities without any impact on public health, quality and nutritional value of food and feed, economy and trade industry become imperative. Various strategies have been adopted to mitigate mycotoxin contamination but often fall short of the required efficacy. One of the promising approaches is the use of bioactive plant components/metabolites synergistically with mycotoxinabsorbing components in order to limit exposure to these toxins and associated negative health effects. In particular, is the fabrication of β-cyclodextrin-based nanosponges encapsulated with bioactive compounds of plant origin to inhibit toxigenic fungi and decontaminate mycotoxins in food and feed without leaving any health and environmental hazard to the consumers. The present paper reviews the use of botanicals extracts and their phytochemicals coupled with β-cyclodextrin-based nanosponge technology to inhibit toxigenic fungal invasion and detoxify mycotoxins.

    Palavras-Chave: mycotoxins; fungi; food; safety; detoxification; plants; botany; toxicity; agriculture

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  • IPEN-DOC 27379

    PEREIRA, S.H.; LIMA, R. de C.; ALVES, M.E.S.; GUIMARÃES, T.M.; JESUS, J.F.; SOUZA, A.P.S. . Cosmology with mass dimension one fields: recent developments. European Physical Journal - Special Topics, v. 229, n. 11, p. 2079-2116, 2020. DOI: 10.1140/epjst/e2020-900271-x

    Abstract: The recent developments with mass dimension one fermionic fields in a cosmological context are briefly presented. The main results for inflation, dark matter, dark energy, cosmological perturbations, particle creation and interacting models are discussed. The Friedmann–Robertson–Walker equations for both torsion and torsion free cases are compared and discussed in different scenarios. We review and call attention for some important assumptions made on derivation of the motion equations. Other approaches and generalizations are suggested and some limitations are presented.

    Palavras-Chave: cosmology; cosmological models; field equations; fermions; einstein field equations; cosmological inflation; inflationary universe; universe; galaxies; growth; gravitational fields

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  • IPEN-DOC 27378

    BIANCOLLI, ANA L.G. ; LOPES, THIAGO; PAGANIN, VALDECIR A.; TICIANELLI, EDSON A.. PEM fuel cells fed by hydrogen from ethanol dehydrogenation reaction: unveiling the poisoning mechanisms of the by-products. Electrochimica Acta, v. 355, p. 1-9, 2020. DOI: 10.1016/j.electacta.2020.136773

    Abstract: This work investigates the influence of hydrogen contaminated with the main by-products of the ethanol dehydrogenation reaction, i.e. ethyl acetate, acetaldehyde and unreacted ethanol, on the anode perfor- mance of a proton exchange membrane fuel cell employing different catalysts, aiming at understanding and minimizing the efficiency losses caused by these molecules. Pt-W/C and Pt-Sn/C catalysts were inves- tigated, having Pt/C as reference, which were chosen due their ability to oxidize small organic molecules without breaking of C –C bonds and without producing strong poisoning intermediates (i.e. less prone to have its active sites blocked by side reactions). Results evidence that anode catalysts that presents lower activity for small organic molecules oxidation and/or weaker reactant adsorption, which is the case of Pt- Sn/C, are best suited for PEMFC systems directly fed by hydrogen from ethanol dehydrogenation reaction. It is also found that crossover of the considered by-products from the anode towards the cathode also has a major impact on fuel cell efficiency losses.

    Palavras-Chave: hydrogen; oxidation; chemical reactions; fuel cells; dehydrogenation; ethanol; catalysts; electrocatalysts; platinum; proton exchange membrane fuel cells

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  • IPEN-DOC 27377

    MIRANDA, RANULFO B. de P.; LEITE, TAYNA P.; PEDRONI, ANA C.F.; MARQUES, MARCIA M.; LIMA, NELSON B. de ; MARCHI, JULIANA; CESAR, PAULO F.. Effect of titania addition and sintering temperature on the microstructure, optical, mechanical and biological properties of the Y-TZP/TiO2 composite. Dental Materials, v. 36, n. 11, p. 1418-1429, 2020. DOI: 10.1016/j.dental.2020.08.014

    Abstract: Objective. The aims of this study were: 1) to evaluate the effect of sintering temperatureon microstructure, density and flexural strength of a 3Y-TZP/TiO2composite containing12.5 wt% of TiO2compared to 3Y-TZP specimens (control); 2) to compare 3Y-TZP with theexperimental 3Y-TZP/TiO2composite, both sintered at 1400°C, with respect to the followingparameters: optical properties, characteristic strength, Weibull modulus, fatigue behavior,induction of osteoblasts proliferation and differentiation (mineralization nodules forma-tion).Methods. The 3Y-TZP and 3Y-TZP/TiO2powders were uniaxially pressed and sintered at 1200°C, 1300°C, 1400°C or 1500°C for one hour in a furnace. The microstructural analysis con-sisted of X-ray diffraction and scanning electron microscopy. The density was measured bythe Archimedes’ principle and the flexural strength was obtained by the biaxial flexure test.The optical properties were measured using a spectrophotometer operating in the visiblelight wavelength range. The step-stress accelerated life testing was performed by the pneu-matic mechanical cycler and the biological behavior achieved by using osteoblast-like cells(Osteo-1 cell line).Results. Tetragonal zirconia was identified in all groups and cubic zirconia was identified onlyat 3Y-TZP group. The addition of TiO2decreased the values of density and flexural strength ofthe composite 3Y-TZP/TiO2in relation to 3Y-TZP regardless of the sintering temperature. Thecolor difference between the two materials was not significant regarding L*a*b* parameters.The composite showed higher probability of failure, and induced higher proliferation anddifferentiation than control. Significance. The composite developed have good aesthetic and biologics properties. However, its microstructure and mechanical properties need to be improved for future dental implant applications.

    Palavras-Chave: nanotubes; titanium oxides; dentistry; implants; yttrium oxides; zirconium oxides; sintering; behavior; biological effects; optical properties; mechanical properties; composite materials; mineralization

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  • IPEN-DOC 27376

    MALAFRONTE, A.A.; PETRI, A.R.; GONCALVES, J.A.C. ; BARROS, S.F.; BUENO, C.C. ; MAIDANA, N.L.; MANGIAROTTI, A.; MARTINS, M.N.; QUIVY, A.A.; VANIN, V.R.. A low-cost small-size commercial PIN photodiode: I. Electrical characterisation and low-energy photon spectrometry. Radiation Physics and Chemistry, v. 179, p. 1-11, 2021. DOI: 10.1016/j.radphyschem.2020.109103

    Abstract: Silicon PIN (p-type-intrinsic-n-type) photodiodes are well suited as particle detectors. Here the interest is on a low-cost solution by repurposing a commercial device meant to be used as a light sensor. The intended application is to measure the energy spectra of electrons scattered by thin metallic foils covering small angles close to the beam of the accelerator. The main requirements for a suitable device are: 1) a low-cost solution to allow frequent replacements; 2) a small size to avoid as much as possible an unused area that contributes with unnecessary capacitance; 3) a good energy resolution; and 4) an easy repurposing as a charged-particle detector. The photodiode type BPX 65 manufactured by Osram® fulfils well these requirements. Four samples of these commercial devices have been electrically characterised with respect to reverse current and depleted-region capacitance. At the selected working point of 18 V, comfortably below the maximum rating of 20 V recommended by the manufacturer for continuous operation, the total thickness of the depleted and intrinsic regions is estimated to be (60 ± 3) μm. For the four samples considered, the measured reverse currents for a reverse bias of 18 V are around 0.1 nA, well below the typical value specified by the manufacturer (1 nA). To evaluate the performance of the device as a detector, energy spectra have been acquired for γ-rays with energies from 10 to 140 keV using 241Am, 133Ba, and 57Co radioactive sources. The resolution of the BPX 65 encountered with the γ-rays emitted by 241Am at 59.5-keV is 2.5 keV (FWHM - Full Width at Half Maximum), which is close to the value obtained with a pulser, showing that its main limitation is the electronic chain employed in the setup. The response function to monoenergetic electrons in the same energy range is studied in the companion paper.

    Palavras-Chave: photodiodes; p-type conductors; silicon; si semiconductor detectors; x-ray spectroscopy; gamma spectroscopy; semiconductor diodes; plasma

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  • IPEN-DOC 27375

    TUSI, MARCELO M.; CANCIAN, RICARDO; POLANCO, NATALY S. de O.; ANAISSI, FAUZE J.; VILLALBA, JUAN C.; OLIVEIRA NETO, ALMIR ; SPINACE, ESTEVAM V. . Synthesis and characterization of PtRu/Carbon hybrids with different metallic load by hydrothermal carbonization method. Ciência e Natura, v. 42, p. 1-15, 2020. DOI: 10.5902/2179460X41273

    Abstract: Híbridos PtRu/Carbono com diferentes cargas metálicas (5, 10 e 20% em massa) foram preparados por carbonização hidrotérmica utilizando celulose como fonte de carbono e agente redutor e H2PtCl6.6H2O e RuCl3.xH2O como fontes de metais e catalisadores do processo de carbonização. Os materiais como-sintetizados foram tratados sob atmosfera de Argônio a 900 °C e caracterizados por espectroscopia por energia dispersiva de raios-X, análise termogravimétrica, difração de raios-X, microscopia eletrônica de transmissão e voltametria cíclica em meio ácido. A eletro-oxidação do methanol foi estudada por cronoamperometria. O material preparado utilizando uma carga metálica de 5% em massa apresentou a melhor eletroatividade para a eletro-oxidação do metanol comparado aos outros materiais provavelmente devido ao menor tamanho de partículas e conteúdo de óxidos superficiais.

    Palavras-Chave: carbonization; hydrothermal systems; platinum alloys; ruthenium alloys; electrocatalysts; fuel cells; methanol; oxidation; electrodes

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  • IPEN-DOC 27374

    RAMOS, ANDREZZA S. ; SANTOS, MONIQUE C.L. ; GODOI, CAMILA M. ; OLIVEIRA NETO, ALMIR ; SOUZA, RODRIGO F.B. de . Obtaining C2 and C3 products from methane using Pd/C as anode in a solid fuel cell-type electrolyte reactor. ChemCatChem, v. 12, n. 18, p. 4517-4521, 2020. DOI: 10.1002/cctc.202000297

    Abstract: Methane was converted into C2 and C3 products under mild conditions using a single stage solid electrolyte reactor, using a proton exchange membrane fuel cell as a SER-FC and Pd/C as an electrocatalyst prepared by the reduction method of sodium borohydride. This electrocatalyst has a cubic pattern of palladium centered on the face and an average size of nanoparticles close to 6.4 nm, according to the literature. Differential mass spectrometry reveals the chemical profile of species obtained from the oxidation of methane with ionic currents (Ii) at m/z=16, 28, 30, 32, 44, 46 and 60. In many cases, Ii can be assigned to more than one species; therefore, complementary ATR-FTIR experiments were performed. The ATR-FTIR spectra confirmed the presence of C2 and C3 compounds such as ethane, ethanol, acetaldehyde, acetic acid and propane. Considering the low amount of water in the reaction medium, these results may be associated with the use of Pd/C electrocatalysts responsible for the activation of the water molecule.

    Palavras-Chave: methane; solid oxide fuel cells; electrolytes; proton exchange membrane fuel cells; electrocatalysts; oxidation; fast reactors

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  • IPEN-DOC 27373

    ALVES, F.M.T. ; CALDAS, L.V.E. . Determinação da dose em pacientes submetidos a exames de tomografia computadorizada de abdome em um serviço de radiologia e diagnóstico por imagem. Brazilian Journal of Radiation Sciences, v. 8, n. 3, p. 1-18, 2020. DOI: 10.15392/bjrs.v8i3.1204

    Abstract: A incorporação de novas tecnologias nos últimos anos proporcionou um aumento expressivo no número de exames de tomografia computadorizada (TC) realizados no mundo e no Brasil e consequentemente seus efeitos deletérios relacionados à radiação ionizante. O objetivo foi verificar a dose dos exames de tomografia computadorizada do abdome realizados em um serviço de radiologia e diagnóstico por imagem para determinar as ações técnicas que visam diminuí-la, bem como suas consequências. Foram analisados os relatórios de dose (emitidos automaticamente pelo próprio aparelho) dos exames de TC de abdome realizados no ano de 2018. As doses estimadas dos exames foram correlacionadas com a indicação clínica, de acordo com o pedido médico, anexado ao cadastro do paciente e ao número de fases realizadas em cada exame. Os resultados dos indicadores avaliados dos exames estavam dentro dos níveis de referência recomendados pela American College of Radiology. Em todas as indicações clínicas foi possível observar uma variabilidade grande no número de fases executadas. Foi possível observar a urgente necessidade de se readequar e padronizar os protocolos de exames dirigidos para a suspeita clínica, permitindo o uso racional com imediata redução no número de fases realizadas e consequentemente minimizar a dose que os pacientes estão recebendo na realização destes exames.

    Palavras-Chave: abdomen; computerized tomography; radiation doses; radiation effects; body; diagnostic techniques

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  • IPEN-DOC 27372

    CASORLA, M. ; BITELLI, U.D. ; ANDRADE, D.A. ; ROCHA, M.S. . Computer simulator for the research reactor IPEN/MB-01. Brazilian Journal of Radiation Sciences, v. 8, n. 3, p. 1-12, 2020. DOI: 10.15392/bjrs.v8i3.1273

    Abstract: A computer simulator for the Nuclear Research Reactor IPEN / MB-01 was developed to be a tool for teaching, training, and recycling professionals. The simulator was developed on a SCADA platform (Supervision and Data Acquisition System) with support calculation software, where mathematical models, and graphical interface configurations form a friendly platform, which allows the trainee to be identified with the physical systems of the research reactor. Simplified modeling of the main physical phenomena related to the operation of the reactor, and the reactivity control systems, reactor cooling and reactor protection was used. The Simulator allows an HMI (Human-Machine Interaction) by manipulating system variables and monitoring trends in quantities during the operation of the reactor, showing an interactive tool for teaching, training and recycling for professionals in the Nuclear Reactor IPEN / MB -01, allowing simulations of the start, power and stop operations.

    Palavras-Chave: computerized simulation; control rooms; ipen-mb-1 reactor; reactivity; reactor cooling systems; reactor protection systems; training

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  • IPEN-DOC 27371

    SANCHES, T.P. ; GENEZINI, F.A. ; SAIKI, M. . A study on trace elements in fingernails and toenails from adult individuals by instrumental neutron activation analysis. Brazilian Journal of Radiation Sciences, v. 8, n. 3, p. 1-18, 2020. DOI: 10.15392/bjrs.v8i3.1281

    Abstract: This study presents results of instrumental neutron activation analysis (INAA) of nails from healthy adult individuals living in São Paulo city, Brazil. Concentrations of As, Br, Ca, Co, Cr, Fe, K, La, Na, Sb, Se and Zn were determined in fingernails and toenails and their variations with gender, age, body mass index among individuals and inter-element correlations were evaluated. These results indicated that several factors might affect in the nail element composition. In addition, there are few published data for finger and toenails analyses. However, comparisons made between the concentrations of elements obtained in fingernails were reasonable within the range of literature values. The findings of this study may contribute to establish an appropriate protocol to obtain data of nail element composition to be used as reference values.

    Palavras-Chave: adults; concentration ratio; elements; nails; neutron activation analysis; quality control; trace amounts

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  • IPEN-DOC 27370

    CASTRO, M.C. ; SILVA, N.F. ; CALDAS, L.V.E. . Some characterization tests for an extrapolation chamber in CT standard beams in a specific chamber depth. Brazilian Journal of Radiation Sciences, v. 8, n. 1A, p. 1-6, 2020. DOI: 10.15392/bjrs.v8i1A.1085

    Abstract: Among all diagnostic exams, the computed tomography (CT) is responsible for the highest dose values to the patients. So, the radiation doses in this procedure must be accurate for the dosimetry procedure in CT scanner beams making use of pencil ionization chambers with sensitive volume lengths of 10 cm. However, there is no primary standard system for this kind of radiation beam. An extrapolation ionization chamber, built at the Cali-bration Laboratory (LCI) was tested to establish a CT primary standard. The aim of this work was to perform some characterization tests (short- and medium-term stabilities, energy dependence, angular dependence) in the standard X-ray beams established for computed tomography at the LCI in a specific chamber depth (1.25 mm). The results showed to be within the international recommended limits except for the energy dependence.

    Palavras-Chave: aluminium; computerized tomography; depth; electrodes; energy dependence; extrapolation chambers; fabrication; radiation detectors; stability; testing; x radiation

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  • IPEN-DOC 27369

    SILVA, C.R. ; PEREIRA, S.T. ; NAPOLITANO, C.M. ; SOMESSARI, E.S.R. ; RIBEIRO, M.S. . Development of a shielding device for radiotherapy of breast cancer-bearing mice. Brazilian Journal of Radiation Sciences, v. 8, n. 1, p. 1-9, 2020. DOI: 10.15392/bjrs.v8i1A.1164

    Abstract: Breast cancer is the fifth most common cause of death worldwide. Currently, one of the standard treatments for breast cancer is radiation therapy (RT). On the other hand, mouse models have been used in pre-clinical studies for breast cancer RT, requiring dedicated shielding to exposure the breast region. In this work, we considered the values of the lead attenuation coefficient and the material tenth reducing layer for 60Co gamma radiation and developed a lead shielding device for breast cancer-bearing mice to be exposed to localized breast RT. Five-kg of lead were heated to of 340ºC and inserted into an aluminum mold previously adjusted to the dimensions of the device. After solidification, the device was shaped into a cylinder with dimension of 14 x 15 x 7 cm (height x width x thickness, respectively). A round cut-out for breast exposure of 1 cm in diameter was made at 5 cm from the basis of the device. For shielding device validation, we performed calibrations to establish a dose of 10 Gy to the target volume. Fifteen CaSO4:Dy thermoluminescent dosimeters were distributed inside the conical tube to mimic the mouse position inside the shielding. The shielding device was placed at a fixed distance of 10 cm from the target for optimal exposure time. After irradiation, the dosimeters were read using a thermoluminescent reader. According to our results, we were able to develop a body-shielding device that assured the required dose for RT of breast cancer in mice.

    Palavras-Chave: absorbed radiation doses; cobalt 60; gamma radiation; ionizing radiations; lead; mammary glands; mice; neoplasms; radiotherapy; shielding; thermoluminescent dosemeters

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  • IPEN-DOC 27368

    ANTONIO, P.L. ; CALDAS, L.V.E. . Comportamento do sinal TL/OSL e PTTL/PTOSL após tratamento térmico pós-irradiação com fonte de 60Co, em amostras de LiF:Mg,Ti e CaSO4:Dy. Brazilian Journal of Radiation Sciences, v. 8, n. 1A, p. 1-16, 2020. DOI: 10.15392/bjrs.v8i1A.1083

    Abstract: Materiais diferentes são utilizados em dosimetria das radiações e podem ter o seu sinal avaliado pelas técnicas de termoluminescência (TL) e luminescência opticamente estimulada (OSL). Outras formas de avaliação são feitas iluminando as amostras com luz ultravioleta (UV) antes da medição do sinal; são as técnicas de TL fototransferida (PTTL) e OSL fototransferida (PTOSL). Para tal, o material deve ser irradiado, tratado termicamente após a irradiação, exposto à luz UV e analisado com relação aos seus sinais PTTL e PTOSL. O LiF:Mg,Ti e o CaSO4:Dy são materiais dosimétricos com dados de TL e OSL já relatados na literatura. Os objetivos deste trabalho foram estudar a presença das respostas PTTL e PTOSL nestas amostras, verificar o efeito que o tratamento térmico pós-irradiação de 280°C/15 min pode causar nestas respostas, e observar se elas apresentam valores suficientes para permitir um prosseguimento destes estudos, para aplicá-las em dosimetria de doses altas. Inicialmente, as amostras foram irradiadas com 60Co (1 kGy) e analisadas com relação aos seus sinais TL e OSL. Na segunda etapa, as pastilhas foram novamente irradiadas, tratadas termicamente (280°C/15 min) e, então, tiveram medições TL, OSL e TL após a OSL, tomadas. Na terceira fase, as amostras foram irradiadas, tratadas termicamente, expostas à luz UV e avaliadas com relação aos sinais PTTL e PTOSL. Os resultados obtidos revelaram dados consideráveis e significativos para o prosseguimento dos estudos dos sinais PTTL e PTOSL das amostras.

    Palavras-Chave: calcium sulfates; cobalt 60; dosimetry; heat treatments; irradiation; light emitting diodes; lithium fluorides; magnesium; thermoluminescence; thermoluminescent dosemeters

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  • IPEN-DOC 27367

    LITVAC, D. ; CALDAS, L.V.E. . Caracterização dosimétrica do LiF-NRPB para calibração de aplicadores clínicos de betaterapia. Brazilian Journal of Radiation Sciences, v. 8, n. 1, p. 1-15, 2020. DOI: 10.15392/bjrs.v8i1A.1087

    Abstract: A National Radiological Protection Board era uma instituição que trabalhava com radioproteção pessoal e utilizava materiais dosimétricos de LiF. Um destes materiais, empregado antigamente na rotina de trabalho da instituição, consiste de uma placa de liga de alumínio, onde dois discos de politetrafluoroetileno carregados com fluoreto de lítio são retidos por anéis de alumínio. São oficializados, no Sistema Único de Saúde, procedimentos radioterápicos em betaterapia dérmica, betaterapia oftalmológica e betaterapia para profilaxia de pterígio. Na norma NN 3.01, “Diretrizes Básicas de Proteção Radiológica”, exige-se a calibração regular destes aplicadores. O objetivo deste trabalho foi caracterizar dosimetricamente as amostras de LiF-NRPB, verificar se são adequadas para utilização em um sistema para calibrações de aplicadores clínicos de betaterapia e identificar se há a possibilidade de novas aplicações dosimétricas.

    Palavras-Chave: angular correlation; beta particles; calibration; dose rates; dose-response relationships; dosimetry; lithium fluorides; microwave ovens; strontium 90; thermoluminescence; yttrium 90

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  • IPEN-DOC 27366

    COELHO, EDNEI; REIS, TATIANA A.; COTRIM, MARYCEL ; RIZZUTTO, MARCIA; CORREA, BENEDITO. Bioremediation of water contaminated with uranium using Penicillium piscarium. Biotechnology Progress, v. 36, n. 5, p. 1-8, 2020. DOI: 10.1002/btpr.3032

    Abstract: Penicillium piscarium can be indicated as promising in the treatment of sites contaminated with uranium. Thus, this research aimed to analyze the P. piscarium dead biomass in uranium biosorption. This fungus was previously isolated from a highly contaminated uranium mine located in Brazil. Biosorption tests were carried out at pH 3.5 and 5.5 in solutions contaminated with concentrations of 1 to 100 mg/L of uranium nitrate. Our results showed that the dead biomass of P. piscarium was able to remove between 93.2 and 97.5% uranium from solutions at pH 3.5, at the end of the experiment, the pH of the solution increased to values above 5.6. Regarding the experiments carried out in solutions with pH 5.5, the dead biomass of the fungus was also able to remove between 38 and 92% uranium from the solution, at the end of the experiment, the pH of the solution increased to levels above 6.5. The analysis of electron microscopy, Energy-dispersive spectroscopy, and X-ray fluorescence demonstrated the high concentration of uranium precipitated on the surface of the fungal biomass. These results were impressive and demonstrate that the dead biomass of P. piscarium can be an important alternative to conventional processes for treating water contaminated with heavy metals, and we hope that these ecofriendly, inexpensive, and effective technologies be encouraged for the safe discharge of water from industrial activities.

    Palavras-Chave: bioremediation; penicillium; uranium; waste water; absorption; biomass; contamination; fungi; water treatment

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  • IPEN-DOC 27365

    CASSOL, HENRIQUE L.G.; DOMINGUES, LUCAS G.; SANCHEZ, ALBER H.; BASSO, LUANA S.; MARANI, LUCIANO; TEJADA, GRACIELA; ARAI, EGIDIO; CORREIA, CAIO ; ALDEN, CAROLINE B.; MILLER, JOHN B.; GLOOR, MANUEL; ANDERSON, LIANA O.; ARAGÃO, LUIZ E.O.C.; GATTI, LUCIANA V. . Determination of region of influence obtained by aircraft vertical profiles using the density of trajectories from the HYSPLIT model. Atmosphere, v. 11, n. 10, p. 1-20, 2020. DOI: 10.3390/atmos11101073

    Abstract: Aircraft atmospheric profiling is a valuable technique for determining greenhouse gas fluxes at regional scales (104–106 km2). Here, we describe a new, simple method for estimating the surface influence of air samples that uses backward trajectories based on the Lagrangian model Hybrid Single-Particle Lagrangian Integrated Trajectory Model (HYSPLIT). We determined “regions of influence” on a quarterly basis between 2010 and 2018 for four aircraft vertical profile sites: SAN and ALF in the eastern Amazon, and RBA and TAB or TEF in the western Amazon. We evaluated regions of influence in terms of their relative sensitivity to areas inside and outside the Amazon and their total area inside the Amazon. Regions of influence varied by quarter and less so by year. In the first and fourth quarters, the contribution of the region of influence inside the Amazon was 83–93% for all sites, while in the second and third quarters, it was 57–75%. The interquarter differences are more evident in the eastern than in the western Amazon. Our analysis indicates that atmospheric profiles from the western sites are sensitive to 42–52.2% of the Amazon. In contrast, eastern Amazon sites are sensitive to only 10.9–25.3%. These results may help to spatially resolve the response of greenhouse gas emissions to climate variability over Amazon.

    Palavras-Chave: aircraft; atmospheres; greenhouses; air quality; sampling; greenhouse gases; air pollution; air flow; carbon dioxide; carbon footprint

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  • IPEN-DOC 27364

    PCHEPIORKA, ROBSON; MOREIRA, MARIA S.; LASCANE, NELISE A. da S.; CATALANI, LUIZ H.; ALLEGRINI JUNIOR, SERGIO; LIMA, NELSON B. de ; GONÇALVES, FLAVIA. Effect of ozone therapy on wound healing in the buccal mucosa of rats. Archives of Oral Biology, v. 119, p. 1-7, 2020. DOI: 10.1016/j.archoralbio.2020.104889

    Abstract: Objective: The objective of this study was to evaluate the effects of ozone therapy on wound healing formed experimentally in the oral cavity of rats. Design: Two surgical wounds were generated on the cheeks of 24 Wistar rats, bilaterally. Half of the animals were submitted to ozone therapy on both wounds (experimental group) and the other half received no treatment (control group). In the experimental group, wounds were exposed to ozone gas 1, 2 or 3 (60 μg/mL) times. Evaluation of wound healing of the buccal mucosa was followed for 1, 3 and 7 days. The distribution of neutrophils, fibroplasia and angiogenesis were analyzed. Samples were classified in a healing numerical scale according to the inflammatory intensity. Data were submitted to Mann-Whitney and Kruskal-Wallis tests (α = 0.05). Results: On day 1, wounds were similar in both groups, lesions were open and bloody with slightly minor bleeding in the ozone therapy group. On day 3, the group with ozone therapy was almost all refurbished and with higher angiogenesis, while the control group still had more bloody points and lower blood vessels. On day 7, both wounds were remodeled, with higher fibroplasia in the group that received ozone therapy. Conclusion: It can be concluded that ozone therapy was effective in improving angiogenesis and fibroblasts count in the buccal mucosa of rats.

    Palavras-Chave: ozone; therapeutic uses; therapy; oral cavity; angiogenesis; healing; biological recovery; mucous membranes; wounds

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  • IPEN-DOC 27363

    YSNAGA, ORLANDO E.; AGUIAR, KELEN M.F.R. de; ZAMBONI, CIBELE B. ; POLITO, WAGNER L.; RODRIGUES-FILHO, UBIRAJARA P.. Qualitative and semiquantitative determination of the atomic and molecular tungsten distributions in hybrid hydroxyurethanes–poly(dimethylsiloxane) films containing phosphotungstates ([PW12O40]3–). Applied Spectroscopy, v. 74, n. 12, p. 1515-1529, 2020. DOI: 10.1177/0003702820945018

    Abstract: In this study, hybrid poly(dimethylsiloxane)-derived hydroxyurethanes films (PDMSUr-PWA) containing phosphotungstic acid (H3PW12O40/PWA) were characterized using field emission gun scanning electron microscopy (FEG-SEM), in attenuated total reflectance Fourier transform mid-infrared mode (ATR FT-MIR), and analyzed using synchrotron radiation micro-X-ray fluorescence (SR-mXRF), synchrotron radiation grazing incidence X-ray fluorescence (SR-GIXRF), laserinduced breakdown spectroscopy (LIBS), and instrumental neutron activation analysis (NAA) in order to correlate the distribution patterns of tungsten and properties of PDMSUr-PWA films. PDMS constitute elastomers with good mechanical, thermal, and chemical (hydrophobicity/non-hygroscopy) resistance. Currently, products based on urethanes (e.g., polyurethanes) are widely used in many applications as plastics, fiber-reinforced polymers, high-performance adhesives, corrosion-resistant coatings, photochromic films, among others. The possibility to combine inorganic and organic components can produce a hybrid material with unique properties. PWA has an important role as agent against the corrosion of steel surfaces in different media, besides exhibiting amazing catalytic and photochromic properties in these films. PWA kept its structure inside of these hybrid films through interactions between the organic matrix of PDMSUr and silanol from the inorganic part (organically modified silica), as was shown using ATR FT-MIR spectra. The FEG-SEM/SR-mXRF/wideangle X-ray scattering (WAXS)/X-ray diffraction (XRD)/energy dispersive X-ray results proved the presence of PWA in the composition of domains of PDMSUr-PWA films. At PWA concentrations higher than 50 wt%/wt, tungsten segregation across the thickness is predominant, while that at PWA concentrations lower than 35 wt%/wt, tungsten segregation at surface is predominant. Inhomogeneities in the tungsten distribution patterns (at micrometric and millimetric level) may play an important role in the mechanical properties of these films (elastic modulus and hardness).

    Palavras-Chave: hydroxy compounds; hybridization; films; synchrotron radiation; neutron activation analysis; spectroscopy; breakdown; laser spectroscopy; x-ray fluorescence analysis; x-ray sources

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  • IPEN-DOC 27362

    SOUZA, CARLA D. de ; ZEITUNI, CARLOS A. ; FEHER, ANSELMO ; MOURA, JOÃO A. ; COSTA, OSVALDO L. da ; ANGELOCCI, LUCAS V. ; ROSTELATO, MARIA E.C.M. . New core configuration for the fabrication of 125I radioactive sources for cancer treatment. Applied Radiation and Isotopes, v. 165, p. 1-8, 2020. DOI: 10.1016/j.apradiso.2020.109307

    Abstract: In order to provide prostate brachytherapy treatment for more Brazilian men, IPEN is building a laboratory for the manufacture of radioactive sources. The new methodology for the production of iodine-125 seeds with yield 71.7% ± 5.3%. Points of importance were evaluated/discussed: photo-sensibility, reaction vial type, the substitution for iodine-131, pH, and solution volume. The surface was analyzed by FTIR and EDS. At the end, a Monte Carlo-MCNP6 simulation was performed to evaluate the TG-43 parameters.

    Palavras-Chave: radiation sources; iodine 125; brachytherapy; radiation chemistry; monte carlo method; neoplasms; tumor cells; prostate; iodination

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  • IPEN-DOC 27361

    AVELAR, ALAN M.; MOURAO, MARCELO B.; MATURANA, MARCOS; GIOVEDI, CLAUDIA; ABE, ALFREDO Y. ; PEDRASSANI, RAFAELA; SU, JIAN. On the nuclear safety improvement by post-inerting small modular reactor with stainless steel cladding. Annals of Nuclear Energy, v. 149, p. 1-8, 2020. DOI: 10.1016/j.anucene.2020.107775

    Abstract: After Fukushima Daiichi accident, the replacement of zirconium-based fuel cladding in Light Water Reactors (LWR) became one of the main challenges of the nuclear industry. Austenitic steel–clad presents some safety advantages comparing to zirconium alloys, noticeably, higher activation energy and lower enthalpy of metal-water reaction. Thus, it produces a slower hydrogen release into the containment following a postulated accident. In this study, a Loss-of-Coolant Accident (LOCA) aggravated by the complete failure of the Emergency Core Cooling System (ECCS) is analyzed for a Small Modular Reactor (SMR). Post-accident injection of inert gas into the containment is used as one of the hydrogen control systems, to enhance safety margins during Severe Accidents (SA). The inertization system is successful in complementing Passive Autocatalytic Recombiners (PAR) to perform combustible gas control.

    Palavras-Chave: radiation protection; stainless steels; hydrogen; small modular reactors; containment; accident management; fukushima accident data; zirconium; fuel-cladding interactions

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  • IPEN-DOC 27360

    ALVARENGA, TALLYSON S. ; POLO, IVON O. ; PEREIRA, WALSAN W.; MAYHUGH, MICHAEL R.; CALDAS, LINDA V.E. . Application of the Reduced-Fitting Method to determine neutron scattering. Radiation Physics and Chemistry, v. 179, p. 1-8, 2021. DOI: 10.1016/j.radphyschem.2020.109207

    Abstract: As the number of techniques using neutron radiation has grown, the number of neutrons detectors has increased along with need for their calibration. In Brazil this substantial demand for neutron detector calibration falls on a single laboratory located in Rio de Janeiro. One of the major problems in the calibration of neutron detectors is neutron scattering, which varies depending on the size and configuration of the laboratory. This is due to the neutrons that interact with the experimental setup and the surrounding, walls, floor and ceiling. This scatter influences the reading of the instrument to be calibrated and causes systematic errors in the calibration of neutron detectors. ISO 8529-2 recommends the following methods to correct these effects: The Semi-Empirical Method (SEM), the Reduced-Fitting Method (RFM), the Shadow-Cone Method (SCM) and the Generalized Fit Method (GFM). In this study, the neutron scattering characterization was performed in the Neutron Calibration Laboratory (LCN) of IPEN/CNEN, using the RFM method. The neutron source used was 241AmBe, which was positioned in the center of the calibration room. Neutron spectra were obtained using a scintillation detector based on 6Lil(Eu) in combination with a Bonner sphere spectrometer (BSS) at source-detector distances from 30 cm to 258 cm.

    Palavras-Chave: scattering; neutrons; radiations; neutron detectors; calibration; calculation methods; bonner sphere spectrometers; neutron spectra

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  • IPEN-DOC 27359

    VIKRANT, K.S.N.; GROSSO, ROBSON L. ; FENG, LIN; MUCCILLO, ELIANA N.S. ; MUCHE, DERECK N.F.; JAWAHARRAM, GOWTHAM S.; BARR, CHRISTOPHER M.; MONTERROSA, ANTHONY M.; CASTRO, RICARDO H.R.; EDWIN GARCIA, R.; HATTAR, KHALID; DILLON, SHEN J.. Ultrahigh temperature in situ transmission electron microscopy based bicrystal coble creep in zirconia I: nanowire growth and interfacial diffusivity. Acta Materialia, v. 199, p. 530-541, 2020. DOI: 10.1016/j.actamat.2020.08.069

    Abstract: This work demonstrates novel in situ transmission electron microscopy-based microscale single grain boundary Coble creep experiments used to grow nanowires through a solid-state process in cu- bic ZrO 2 between ≈1200 °C and ≈2100 °C. Experiments indicate Coble creep drives the for- mation of nanowires from asperity contacts during tensile displacement, which is confirmed by phase field simulations. The experiments also facilitate efficient measurement of grain boundary diffusivity and surface diffusivity. 10 mol% Sc 2 O 3 doped ZrO 2 is found to have a cation grain boundary diffusivity of D gb = ( 0 . 056 ±0 . 05 ) exp ( −380 , 0 0 0 ±41 , 0 0 0 RT ) m 2 s −1 , and surface diffusivity of D s = ( 0 . 10 ±0 . 27 ) exp ( −380 , 0 0 0 ±28 , 0 0 0 RT ) m 2 s −1 .

    Palavras-Chave: creep; temperature range 0400-1000 k; transmission electron microscopy; transmission; zirconium oxides; nanowires; grain boundaries

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  • IPEN-DOC 27358

    GROSSO, ROBSON L. ; VIKRANT, K.S.N.; FENG, LIN; MUCCILLO, ELIANA N.S. ; MUCHE, DERECK N.F.; JAWAHARRAM, GOWTHAM S.; BARR, CHRISTOPHER M.; MONTERROSA, ANTHONY M.; CASTRO, RICARDO H.R.; EDWIN GARCIA, R.; HATTAR, KHALID; DILLON, SHEN J.. Ultrahigh temperature in situ transmission electron microscopy based bicrystal coble creep in Zirconia II: interfacial thermodynamics and transport mechanisms. Acta Materialia, v. 200, p. 1008-1021, 2020. DOI: 10.1016/j.actamat.2020.08.070

    Abstract: This work uses a combination of stress dependent single grain boundary Coble creep and zero-creep ex- periments to measure interfacial energies, along with grain boundary point defect formation and migra- tion volumes in cubic ZrO 2 . These data, along with interfacial diffusivities measured in a companion paper are then applied to analyzing two-particle sintering. The analysis presented indicates that the large acti- vation volume, v ∗= v f + v m primarily derives from a large migration volume and suggests that the grain boundary rate limiting defects are delocalized, possibly due to electrostatic interactions between charge compensating defects. The discrete nature of the sintering and creep process observed in the small-scale experiments supports the hypothesis that grain boundary dislocations serve as sources and sinks for grain boundary point defects and facilitate strain during sintering and Coble creep. Model two-particle sintering experiments demonstrate that initial-stage densification follows interface reaction rate-limited kinetics.

    Palavras-Chave: grain boundaries; creep; transmission electron microscopy; temperature range 0400-1000 k; zirconium oxides; sintering; bicrystals; thermodynamics

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  • IPEN-DOC 27357

    SÁ, ANA P.N. de ; NEGRAO, BIANCA G. ; NABESHIMA, ELIZABETH H.; KOIKE, AMANDA C.R. ; VILLAVICENCIO, ANNA L.C.H. . Effect of ionizing radiation on traditional and bacon “farofa”. Radiation Physics and Chemistry, v. 179, p. 1-7, 2021. DOI: 10.1016/j.radphyschem.2020.109109

    Abstract: Seasoned “farofa” is a typical Brazilian dish made with toasted cassava flour. It is known that ionizing radiation is widely employed to improve food products extending its shelf life. In this context, this work analyzes the effects of ionizing radiation on the rheological and physicochemical properties of bacon (BF) and traditional (TF) “farofa”. The samples were obtained from local markets (São Paulo/Brazil) and irradiated in the electron beam accelerator of Nuclear and Energy Research Institute (IPEN/CNEN-SP, São Paulo, Brazil) in doses of 1, 5 and 10 kGy, and analyzed on the first, fifteenth and thirtieth storage day. The results showed that the irradiated TF and BF samples displayed acidic pH throughout the storage period, regardless of dose increase. The different irradiation doses did not significantly affect (Tukey test p > 0.05) the water activity, keeping the products in the safe range. The colorimetric analysis, also showed no significant difference (p ≥ 0.05) among the samples and ionizing radiation doses, indicating that the yellowish coloration remained stable throughout the experiment. After the thirtieth day, the moisture of the TF and BF samples ranged from 7.06% to 9.75%. Irradiation had a significant impact on the viscosity profile and texture characteristics of the “farofa”, such as hardness, cohesiveness, and the springiness at 5 and 10 kGy.

    Palavras-Chave: chemical properties; flour; food industry; food processing; ionizing radiations; oxidation; radiation dose units; radiation effects; radurization; technology utilization

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  • IPEN-DOC 27356

    CORAZZA, FULVIO G.; ERNESTO, JULIA V.; NAMBU, FELIPE A.N.; CALIXTO, LEANDRO A.; VARCA, GUSTAVO H.C. ; VIEIRA, DANIEL P. ; LEITE-SILVA, VANIA R.; ANDREO-FILHO, NEWTON; LOPES, PATRICIA S.. Enhancing the furosemide permeability by papain minitablets through a triple co-culture in vitro intestinal cell model. AAPS PharmSciTech, v. 21, n. 7, p. 1-10, 2020. DOI: 10.1208/s12249-020-01796-9

    Abstract: The administration of medicines by the oral route is the most used approach for being very convenient. Although it is the most popular, this route also has absorption, and consequently, bioavailability limitations. In this sense, several pharmacotechnical strategies have been used to improve drug absorption, one of which is the use of permeation promoters. Papain is a very versatile plant enzyme that can be used as a permeation promoter of various active compounds. This study aimed to evaluate the safety of papain and the formulation of native papain minitablets to promote in vitro permeation of furosemide through an innovative biomimetic triple co-culture model of Caco-2, HT29-MTX, and Raji cells. Regarding permeation, furosemide and metaprolol concentrations are determined with HPLC; those are used to calculate Papp. Monolayer integrity was evaluated using TEER and Lucifer Yellow. In the presence of papain, TEER decreased two-fold and the Papp of furosemide increased six-fold. The results suggest that native papain minitablets can be used as therapeutic adjuvants to enhance the permeation of drugs significantly improving bioavailability.

    Palavras-Chave: drugs; diuretics; papain; permeability; in vitro; animal cells; intestines; mucous membranes; cell cultures; electrical properties

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  • IPEN-DOC 27355

    MAIA, TIAGO C. dos S. ; LUGAO, ADEMAR B. ; AZOUBEL, ROBERTA; RAPOSO, MARCOS T.; OLIVEIRA, MARIA J.A. de . Effect of gamma radiation cobalt-60 on caffeine. International Journal of Development Research, v. 9, n. 5, p. 27749-27751, 2019.

    Abstract: Objective: The objective of the study was to evaluate the effects of the incidence of gamma radiation of Cobalt-60 on caffeine. Material and Methods: The samples were studied in aqueous solution and powdered form after irradiation at doses: 2, 4, 8, 16 and 32 kGy by ionizing radiation source of 60Co. After wards, they were analyzed by differential scanning calorimetry (DSC), thermogravimetry (TG), and high performance liquid chromatography (HPLC). Results and Discussion: For the DSC technique no changes were observed in the curves after irradiation, which could witness changes in physicochemical properties after irradiation. The TG corroborated with the expected mass loss of caffeine, independent of the action of ionizing radiation. Furthermore, the results obtained by the chromatographic analysis did not show a percentage of caffeine degradation in the dose of the applied radiation when compared to the nonirradiated caffeine. Conclusion: In view of the results obtained, it was possible to observe the stability of caffeine on the influence of gamma radiation on the Cobalt-60 source.

    Palavras-Chave: gamma radiation; cobalt 60; ionizing radiations; caffeine; chromatography; thermal gravimetric analysis; biological radiation effects

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  • IPEN-DOC 27354

    SALES, JORGE N. de . Efeito da incorporação da argila Verde Lago nas propriedades do polipropileno / Effect of the incorporation of clay Verde Lago in the properties of polypropylene . 2020. Tese (Doutorado em Tecnologia Nuclear) - Instituto de Pesquisas Energéticas e Nucleares - IPEN-CNEN/SP, São Paulo, SP. 106 p. Orientador: Leonardo Gondim de Andrade e Silva. DOI: 10.11606/T.85.2020.tde-24092020-153819

    Abstract: O polipropileno é um polímero cristalizável, pois possui regularidade em sua estrutura e polaridade em seus grupos laterais. O grau de cristalinidade de um polímero interfere em uma série de propriedades deste tipo de material. Neste trabalho a argila Verde Lago foi caracterizada por meio dos ensaios de fluorescência de raios X e difração de raios X, organofilizada e incorporada à matriz polimérica de polipropileno em adições de 0,5%, 1% e 2%, em massa. A eficiência do processo de organofilização foi verificada por meio dos ensaios de inchamento Foster, difração de raios X e espectroscopia vibracional de absorção no infravermelho com transformada de Fourier. As formulações propostas tiveram suas propriedades avaliadas pelos ensaios de resistência à tração, resistência ao impacto Izod, análises termogravimétricas, calorimetria exploratória diferencial, ensaios colorimétricos CIE Lab, índice de fluidez e microscopia eletrônica de varredura. Os resultados obtidos foram comparados às formulações produzidas na mesma condição com o agente nucleante comercial Hyperform HPN-20E. O processo de organofilização da argila Verde Lago se mostrou eficiente e as formulações preparadas com a argila Verde Lago organofilizada e com o agente nucleante comercial apresentaram elevação na tensão na ruptura e redução em sua deformação. As formulações preparadas com a argila Verde Lago resultaram em um menor decréscimo na propriedade de resistência ao impacto Izod do que as formulações preparadas com o agente nucleante comercial. Todas as formulações preparadas geraram uma elevação no índice de cristalinidade do polipropileno e não alteraram a estabilidade térmica do material próximo a sua temperatura de trabalho além de não apresentarem uma grande alteração no índice de fluidez. As microscopias realizadas mostraram dispersões similares para as formulações preparadas. As formulações feitas com a argila Verde Lago se mostraram mais amareladas e opacas que as formulações feitas com o nucleante comercial. Os resultados obtidos permitiram concluir que a argila Verde Lago foi efetiva como agente nucleante para o polipropileno.

    Palavras-Chave: crystallization; polarizability; polypropylene; polymers; physical properties; clays; smectite; additives; materials testing; performance testing; impact tests; wear resistance; ruptures; stress analysis; deformation; x-ray diffraction; fluorescence; thermal gravimetric analysis; differential thermal analysis

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  • IPEN-DOC 27353

    BASEIO, JOAO H.B. . Efeito da adição de silício na reação AI/U7Mo em dispersões combustíveis à base de UMo-AI / Effect of silicon addition on Al/U7Mo reaction in UMo-Al fuel dispersions . 2020. Dissertação (Mestrado em Tecnologia Nuclear) - Instituto de Pesquisas Energéticas e Nucleares - IPEN-CNEN/SP, São Paulo, SP. 5 p. Orientador: Michelangelo Durazzo. Coorientador: Ricardo Mendes Leal Neto. DOI: 10.11606/D.85.2020.tde-24092020-152910

    Observação: Há arquivos retidos devido a solicitação (publicação de dados, patentes ou diretos autorais). Data de Liberação: 19/02/2024.

    Abstract: No contexto do programa de redução do enriquecimento de urânio em reatores nucleares de pesquisa, combustíveis com alta densidade de urânio tem sido considerados e estudados, incluindo-se as dispersões à base de UMo-Al, alternativa próxima de ser implantada comercialmente. No entanto, a reação entre as partículas de UMo e a matriz de alumínio tem que ser controlada, em prol da estabilidade do combustível sob as condições de fabricação e operação. A adição de Si à matriz de Al sobre a reação entre as partículas de UMo e a matriz é uma das soluções possíveis apontadas na literatura para melhorar o desempenho sob irradiação desse tipo de combustível. Foram estudadas duas formas de incorporação de Si à matriz: mistura mecânica simples dos pós de Al e Si e a comoagem de alta energia de ambos os pós. Avaliou-se também o efeito da concentração de Si na matriz de Al. Por meio de análise térmica diferencial foi demonstrado que a incorporação de Si via comoagem diminuiu sensivelmente a reação do Al com o UMo, sendo comparável com o comportamento da dispersão de U3Si2 em Al, adotada como padrão, por ser um combustível já qualificado internacionalmente. O efeito da incorporação via mistura mecânica foi bem menor. Foi verificado também que maiores teores de silício são mais eficientes para o controle da reação. Os melhores resultados da comoagem foram atribuídos à superior homogeneidade da distribuição de Si na matriz de Al.

    Palavras-Chave: nuclear fuels; manufacturers; operation; uranium dioxide; aluminium alloys; uranium-molybdenum fuels; silicon additions; nuclear matrix; stability; dispersions; milling; differential thermal analysis

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  • IPEN-DOC 27352

    FERREIRA, ARYEL H. . Avaliação de nanopartículas proteicas radiomarcadas dirigidas a tecidos tumorais como agentes diagnósticos / Evaluation of radiolabeled protein-based nanoparticles to target tumor tissue as a potential diagnosis agent . 2020. Tese (Doutorado em Tecnologia Nuclear) - Instituto de Pesquisas Energéticas e Nucleares - IPEN-CNEN/SP, São Paulo, SP. 6 p. Orientador: Ademar Benévolo Lugão. DOI: 10.11606/T.85.2020.tde-24092020-145109

    Observação: Há arquivos retidos devido a solicitação (publicação de dados, patentes ou diretos autorais). Data de Liberação: 09/03/2024.

    Abstract: Recentes avanços em nanomedicina e nanotecnologia têm expandido o desenvolvimento de nanoestruturas multifuncionais que combinem especificidade e funções terapêuticas e de diagnóstico em complexos nanoestruturados, a fim de superar barreiras biológicas que podem dificultar a administração e a captação seletiva e eficaz de medicamentos e agentes diagnósticos em tecidos tumorais. Nanopartículas vêm sendo utilizadas em Medicina Nuclear como carreadores de radionuclídeos emissores de radiação gama (γ) ou pósitron (+1β) para imagens diagnósticas por PET, SPECT e emissores de partículas α e -1β utilizados em endorradioterapia para destruir especificamente o tecido tumoral. O objetivo deste trabalho concentrou-se no estudo da marcação com Tecnécio-99m de nanopartículas de papaína e albumina, sintetizadas por reticulação induzida por radiação, e na caracterização de seus comportamentos in vitro e in vivo, de modo a desenvolver novos nanorradiofármacos e avaliar seu potencial para realização de diagnóstico de tumores mamários utilizando a técnica de medicina nuclear SPECT. Técnicas de microscopia eletrônica e espalhamento de luz evidenciaram formação de nanopartículas esféricas com dispersão de tamanho de 9,3 ± 1,9 nm para as nanopartículas de papaína e 25,1 ± 2,9 nm para as nanopartículas de albumina. Um elevado rendimento radioquímico (>90%) e estabilidade frente aos agentes transquelantes presentes no soro foram observados para ambas as nanopartículas até pelo menos 6h. A biodistribuição em animais saudáveis demonstrou diferentes perfis de excreção, sendo a 99mTc-P-NPs excretada principalmente pelo rim, enquanto a 99mTc-BSA-NPs é excretada principalmente por via hepática. Nos estudos in vitro, as nanopartículas mostraram-se promissoras com 74% e 57,6% da captação total em células MDA-MB231, respectivamente para 99mTc-P-NPs e 99mTc-BSA-NPs. Nos estudos in vivo verificou-se acentuada captação tumoral com boa visualização em imagens adquiridas em micro-SPECT/CT. Deste modo, as nanopartículas proteicas utilizadas no corrente trabalho mostraram-se promissoras para serem utilizadas como sistema de veiculação de radionuclídeos diagnósticos para estudos de sua distribuição sistêmica, bem como de sua aplicação como traçador SPECT em tumores mamários.

    Palavras-Chave: neoplasms; tumor cells; blood cells; gamma radiation; technetium 99 target; product labeling; microstructure; nanotechnology; proteins; carriers; albumins; blood serum; enzymes; papain; excretion; physiology; biological effects; in vivo; in vitro; positron computed tomography; single photon emission computed tomography; biological localization; diagnosis; radiotherapy

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  • IPEN-DOC 27351

    KLUMPP, RAFAEL E. . Desenvolvimento de tratamento por tecnologia limpa para a superfície da liga AA2024 com clad AA1230 / Development of clean technology treatments for AA2024-T3 alloy surface with AA1230 clad. 2020 . 2020. Tese (Doutorado em Tecnologia Nuclear) - Instituto de Pesquisas Energéticas e Nucleares - IPEN-CNEN/SP, São Paulo, SP. 156 p. Orientador: Isolda Costa. DOI: 10.11606/T.85.2020.tde-24092020-154830

    Abstract: Há grande interesse na busca por tratamentos de superfície por tecnologia limpa para substituição dos tratamentos que geram rejeitos altamente tóxicos, mutagênicos e carcinogênicos, como é o caso dos tratamentos em meios contendo íons de cromo hexavalente para proteção contra a corrosão de ligas de alumínio. Neste trabalho, foram testados vários tratamentos para a superfície da liga AA2024-T3 Clad visando a resistência à corrosão para substituição dos tratamentos que utilizam cromo hexavalente, alguns realizados em várias etapas, e outros em etapa única. As superfícies da liga AA2024-T3 Clad, após tratamentos selecionados com base em resultados do ensaio de névoa salina (ASTM B117), foram caracterizadas química, morfológica e eletroquimicamente. O efeito dos tratamentos testados na resistência à corrosão da liga AA2024-T3 Clad foi estudado. A composição química da superfície após tratamentos foi investigada por espectroscopia de fotoelétrons excitados por raios-X (XPS); a morfologia por microscopia eletrônica de varredura (MEV) e microscopia de força atômica (AFM), e a resistência à corrosão por técnicas eletroquímicas globais, especificamente espectroscopia de impedância eletroquímica (EIE) e curvas de polarização anódica, e técnicas eletroquímicas locais, tais como, a técnica de varredura do eletrodo vibratório (SVET).A resistência à corrosão foi também avaliada pelo ensaio acelerado de névoa salina (ASTM B117). As superfícies após tratamentos foram caracterizadas quanto a tensão superficial e adesão à uma camada de verniz. Dos resultados obtidos foi proposto um tratamento de etapa única baseado em um híbrido Sol-Gel modificado com nitrato de cério, processo que não gera resíduos tóxicos. Os resultados deste tratamento foram comparados com os da mesma liga com revestimento de conversão obtido em solução contendo íons de cromo hexavalente. A resistência à corrosão da superfície com o tratamento selecionado entre os testados foi similar ao do tratamento de conversão em solução com cromo hexavalente. Além disso, a superfície com o tratamento proposto apresentou ótima adesão à camada de verniz. Os resultados indicaram que o tratamento proposto é uma alternativa viável para substituição de tratamentos que geram resíduos tóxicos e cancerígenos, com a vantagem em relação aos tratamentos que vêm sendo propostos na literatura de ser obtido em um processo de etapa única.

    Palavras-Chave: surface treatments; surface coating; surface ionization; cladding; varnishes; aluminium alloys; corrosion protection; corrosion resistance; performance testing; mode conversion; environmental protection; health hazards; insurance; safety margins; chromium oxides; dichromates; salts; cerium nitrides; sol-gel process; hydride moderators; x-ray photoelectron spectroscopy; scanning electron microscopy; atomic force microscopy; electrochemical cells; impedance; probes; scanning tunneling microscopy; electrodes; signal conditioners

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  • IPEN-DOC 27350

    AGODI, C.; CAPPUZZELLO, F.; ACOSTA, L.; AMADOR-VALENZUELA, P.; AUERBACH, N.; BAREA, J.; SILVEIRA, M.A.G. da; BELLONE, J.; BELMONT, D.; BIJKER, R.; BONANNO, D.; BORELLO-LEWIN, T.; BOZTOSUN, I.; BRANCHINA, V.; BRASOLIN, S.; BRISCHETTO, G.; BRUNASSO, O.; BURRELLO, S.; CALABRESE, S.; CALABRETTA, L.; CALVO, D.; CAPIROSSI, V.; CARBONE, D.; CAVALLARO, M.; CHAVEZ LOMELI, E.R.; CHEN, R.; CIRALDO, I.; COLONNA, M.; D’AGOSTINO, G.; DE FARIA, P.N.; DE GERONIMO, G.; DEHSMUKH, N.; DELAUNAY, F.; DJAPO, H.; ESPEJEL, R.; FERRARESI, C.; FERREIRA, J.L.; FERRETTI, J.; FINOCCHIARO, P.; FIRAT, S.; FISICHELLA, M.; FLORES, A.; FOTI, A.; GALLO, G.; GARCIA-TECOCOATZI, H.; GONGORA, B.; HACISALIHOGLU, A.; HAZAR, S.; HUERTA, A.; IAZZI, F.; KOTILA, J.; KUCUK, Y.; LA VIA, F.; LANZALONE, G.; LAY, J.A.; LENSKE, H.; LINARES, R.; LO PRESTI, D.; LONGHITANO, F.; LUBIAN, J.; MA, J.; MARIN-LAMBARRI, D.; MARTINEZ, S.; MAS, J.; MEDINA, N.; MENDES, D.R.; MEREU, P.; MORALLES, M. ; OLIVEIRA, J.R.B.; ORDONEZ, C.; PAKOU, A.; PANDOLA, L.; PETRASCU, H.; PIETRALLA, N.; PINNA, F.; REITO, S.; REZA, G.; RIES, P.; RIFUGGIATO, D.; RODRIGUES, M.; RUSSO, G.; RUSSO, A.D.; SANDOVAL, S.; SANTOPINTO, E.; SANTOS, R.B.B.; SCALTRITO, L.; SGOUROS, O.; SOLAKCI, S.O.; SOUKERAS, V.; SOULIOTIS, G.; SPATAFORA, A.; TUDISCO, S.; VARGAS, H.; VEGA, G.; VEGA, G.; WANG, J.S.; WERNER, V.; YANG, Y.Y.; YILDRIN, A.; ZAGATTO, V.A.B.. New results from the NUMEN project. In: MARRONE, ANTONIO (Ed.); MIRIZZI, ALESSANDRO (Ed.); MONTANINO, DANIELE (Ed.) NEUTRINO OSCILLATION WORKSHOP, September 9-16, 2018, Ostuni, Brindisi, Italy. Resumo expandido... Trieste, Italy: Proceedings of Science, 2018. p. 1-5.

    Abstract: The idea of NUMEN project is to study heavy-ion induced Double Charge Exchange (DCE) reactions with the aim to get information on the nuclear matrix elements for neutrinoless double beta (0nbb) decay. To infer the neutrino average masses from the possible measurement of the halflife of 0nbb decay, the knowledge of the nuclear matrix elements is crucial. DCE reactions and 0nbb decay present some similarities, the initial and final-state wave functions are the same and the transition operators are similar. The experimental measurements of DCE reactions induced by heavy ions present a number of challenging aspects, since they are characterized by very low cross sections.

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  • IPEN-DOC 27349

    VAZ, ANTONIO C.A. ; BORGES, VINICIUS F. ; GENEZINI, FREDERICO A. ; RODRIGUES, VALDEMIR G. ; SILVA, DAVILSON G. da . Human factors evaluation in operators with attention to insider threat detection. In: INTERNATIONAL CONFERENCE ON NUCLEAR SECURITY, February 10-14, 2020, Vienna, Austria. Poster... 2020.

    Palavras-Chave: human factors; research reactors; control rooms; personnel; reactor operators; training; behavior; reactors

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  • IPEN-DOC 27348

    LEMOS, F.L. ; BIANCHI, P.H. . A systemic approach to information and cyber security. In: INTERNATIONAL CONFERENCE ON NUCLEAR SECURITY, February 10-14, 2020, Vienna, Austria. Proceedings... 2020. p. 1-6.

    Abstract: Design Based Threat, or DBT, is a common principle for physical and cyber protection, which is based on threat assessments. The protection, cyber or physical, will be planned based on the type of the identified threat. While we acknowledge the importance of the DBT, we argue that following this line of reasoning may limit our ability to grasp other vulnerabilities the system may have due to the following assumptions: a) The system will behave according to the way we think it should, based on a predetermined fashion. b) If each component of the system is reliable, then the system will be reliable. Systems theory assumes that accidents are a result of systemic factors, and does not have a single root-cause, generally a failure, that starts a chain of events leading to the accident. Moreover, systems theory assumes that security and safety are emergent properties of a system that result from the interactions between the components of that system. Therefore, accidents are a problem of control of the interactions between the components of the system rather than a problem of failures of components. In the systemic approach a cyber security system is treated as part of the whole socio-technical complex system, where humans are components of the system and interact with the computerized controls. The organizational culture permeates the entire system affecting decisions and, consequently, the interactions between the components. Weak safety and security cultures will eventually contribute for the system to migrate to hazardous states leading to losses or accidents. The paper analyzes the roles of organizational, safety and security cultures, as underlying factors that can lead to the deterioration of the hierarchical control structure, which is supposed to keep the interactions between the components of the system within desirable constraints.

    Palavras-Chave: cybernetics; security; risk assessment; information systems; organizational models; management

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  • IPEN-DOC 27347

    LIMA, MARIANA ; BONTURIM, EVERTON ; ANDREOLI, MARCO ; LIMA, NELSON B. de ; SEO, EMILIA S.M. . Obtenção e caracterização de BaxSr1-xCoyFe1-yO3±δ para preparação de camada funcional do eletrodo catódico das células a combustível do tipo IT-SOFC. In: HOLZMANN, HENRIQUE A. (Org.); DALLAMUTA, JOÃO (Org.); MAZUR, VIVIANE T. (Org.). As engenharias e seu papel no desenvolvimento autossustentado. Ponta Grossa, PR: Atena, 2020. p. 294, cap. 19. DOI: 10.22533/at.ed.46620300619

    Abstract: A demanda mundial por energia elétrica é uma tendência crescente, desta maneira há necessidade de diversificar e buscar por novas matrizes energéticas. Insere-se neste contexto, as células a combustível de Óxido Sólido de Temperatura Intermediária (Intermediate Temperature Solid Oxide Fuel Cells - IT-SOFC), que converte diretamente a energia de reações químicas em água e em energia elétrica e também em energia térmica (calor). As células a combustível do tipo IT-SOFC por utilizarem materiais cerâmicos em sua concepção, são capazes de suportarem temperaturas até 800ºC e sem perderem suas propriedades físicas, químicas, elétricas e microestruturais. O presente trabalho tem como objetivo a síntese e a caracterização do material particulado de BaxSr1-xCoyFe1- yO3±δ – BSCF (variando os valores de x iguais a 0,4; 0,6 e 0,5), visando sua utilização para fabricação de componente catódico de IT-SOFC. O particulado de BSCF foi obtido por meio do método de complexação por EDTA – Citratos, que consiste nas reações de estado sólido e reações em fase líquida. A reação em fase líquida consiste no processo de complexação em que os agentes quelantes atraem os íons metálicos presentes na solução precursora. A caracterização do material particulado BSCF foi realizada por difração de raios X (DRX), Espectroscopia de raios X por energia dispersiva (EDS), Análise Química por Fluorescência de raios X (identificação dos elementos constituintes na composição), Análise de Microscopia Eletrônica de Varredura - MEV (observação de morfologia e do tipo de aglomeração das partículas), e Picnometria por Gás Hélio (medidas de densidade real) e BET. Os resultados da caracterização dos particulados para a confecção do material catódico do BSCF apresentaram adequados para fabricação de componente catódico de IT-SOFC.

    Palavras-Chave: fuel cells; ceramics; solid oxide fuel cells; synthesis; energy; edta; x-ray fluorescence analysis

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  • IPEN-DOC 27346

    MUNITA, CASIMIRO S. ; BATALLA, NICOLAS; COSTA, ANGISLAINE F.; BARROS, JOANNA F. ; NOGUEIRA, ANDRE L.; CARVALHO, PATRICIA R. ; CARVALHO, PRISCILLA R. . Explorando problemas arqueológicos com técnicas físico-químicas: a trajetória do Grupo de Estudos Arqueométricos do Instituto de Pesquisas Energéticas e Nucleares, São Paulo, Brasil / Exploring archaeological problems with physico-chemical techniques: the trajectory of the Group of Archaeometric Studies of the Nuclear and Energy Research Institute, São Paulo, Brazil. Boletim do Museu Paraense Emílio Goeldi. Ciências Humanas, v. 15, n. 3, p. 1-19, 2020. DOI: 10.1590/2178-2547-BGOELDI-2020-0004

    Abstract: O presente artigo traz uma revisão da principal literatura produzida pelo Grupo de Estudos Arqueométricos do Instituto de Pesquisas Energéticas e Nucleares, Comissão Nacional de Energia Nuclear, de São Paulo (IPEN-CNEN/SP), criado em 1997, como consequência de uma iniciativa internacional para motivar o uso de técnicas nucleares para caracterização de materiais arqueológicos. Desde aquele momento, e até hoje, o grupo tem desenvolvido parcerias com pesquisadores/as de diferentes regiões do Brasil e de outros países para oferecer subsídios à compreensão interdisciplinar das cadeias operatórias de produção da cerâmica. Além disso, também vem aportando dados para o estudo multielementar e mineralógico de depósitos arqueológicos. Ao descrever brevemente os princípios das técnicas empregadas e a síntese dos resultados obtidos para cada estudo de caso, o objetivo foi demonstrar a contribuição das análises físico-químicas para questões relacionadas a aspectos culturais, como escolhas tecnológicas compartilhadas, redes de trocas e interações sociais em diferentes períodos do passado.

    Palavras-Chave: archaeology; archaeological specimens; historical aspects; chemical properties; archaeological sites; ceramics; cultural objects; brazil

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  • IPEN-DOC 27345

    SARRA, G.; SCARDINI, I.L.; ZEZELL, D.M. ; MACHADO, E.L.M.; GAVINI, G.; CALDEIRA, C.L.; SANTOS, M.. Avaliação da superfície de intrumentos WaveOne e WaveOne Gold novos e após o uso. In: CONGRESSO INTERNACIONAL DA SBENDO, 11th, September 26-28, 2019, Fortaleza, CE. Poster... 2019.

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  • IPEN-DOC 27344

    ZEZELL, DENISE M. . Biophotonics and lasers shining light into diseases. In: ENCONTRO DE FÍSICOS DO NORTE E NORDESTE, 34., 3-5 de novembro, 2019, Maceió, AL. Resumo... 2019.

    Abstract: Light-tissue interaction became the basis of many sciences. The development of new diagnostic and therapeutic methods in Dentistry and Medicine based on Photonics, have been performed at the Center for Lasers and Applications, IPEN-CNEN/SP, Brazil in the last 27 years, in close cooperation with School of Dentistry and Faculty of Medicine of USP, UNIFESP, etc, as well as other Physics departments such as UFPE and FFCLRP- USP. The study of the spectroscopic properties of biological tissues can be used as a diagnostic tool for various diseases, as well as to determine their different stages. My group has been studying normal, precancerous and tumor tissues, such as thyroid, lung, skin, as well as hard dental tissues by FTIR. Results of studies that have become clinical methods, such as the prevention of dental caries or the diagnosis of various stages of dental enamel lesion, will be presented. Fluorescence spectroscopy was used to monitor carious lesions. The evaluation of optical coherence tomography (OCT) images obtained during the during the caries or erosion development process, or after the ionizing irradiation of bones, provide information on the optical attenuation coefficient, which is related to the lesion stage. The application of ultra-short high intensity laser (femtosecond laser) to ablate hard tissue, resin, ceramics, or burned skin is underway.

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  • IPEN-DOC 27343

    PIERETTI, EURICO F. ; NEVES, MAURICIO D.M. das ; ANTUNES, RENATO A.. Estudo da degradação de um biomaterial metálico tratado a laser. In: CONGRESSO BRASILEIRO DE BIOMECÂNICA, 18th; ENCONTRO LATINO AMERICANO DE BIOMECÂNICA, 2nd, May 1-4, 2019, Manaus, AM. Abstract... Manaus, AM: Maloka Publicidade, 2019. p. 212-212.

    Abstract: Biomateriais tratam, auxiliam ou substituem partes do corpo humano para que estas possam desempenhar as suas funções adequadamente. Estes devem apresentar composição química adequada e condição de superfície apropriada, de maneira que não sejam rejeitados durante o período em que estiverem inseridos no corpo. A seleção do biomaterial a ser utilizado deve levar em consideração as propriedades físicas, químicas e biomecânicas do biomaterial. As principais propriedades que devem ser levadas em conta são: rugosidade, resistência mecânica, módulo de elasticidade, flexão e torção, resistência à fadiga, resistência à corrosão. Os dispositivos médicos implantáveis sofrem degradação, o que pode causar hipersensibilidade ou a necessidade de uma nova cirurgia para remoção e substituição. O presente trabalho teve o objetivo de avaliar o efeito do tratamento superficial a laser na resistência à degradação de amostras de implantes ortopédicos produzidos em aço inoxidável austenítico ISO 5832-1, um dos mais utilizados no Brasil para a confecção de próteses e implantes. Foram realizados testes eletroquímicos, in vitro, em solução tamponada de fosfato, de pH 7,4 em temperatura corpórea de 37ºC, simulando um período superior a uma década de implantação. Os testes consistiram no monitoramento do potencial de corrosão em função do tempo de imersão, espectroscopia de impedância eletroquímica e polarização potenciodinâmica cíclica. Os resultados desta pesquisa permitiram concluir que a técnica de tratamento superficial a laser para biomateriais metálicos teve efeito deletério na resistência à corrosão localizada.

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  • IPEN-DOC 27342

    PIERETTI, EURICO F. ; NEVES, MAURICIO D.M. das ; ANTUNES, RENATO A.. Avaliação de biomaterial texturizado a laser para aplicações ortopédicas. In: CONGRESSO BRASILEIRO DE BIOMECÂNICA, 18th; ENCONTRO LATINO AMERICANO DE BIOMECÂNICA, 2nd, May 1-4, 2019, Manaus, AM. Abstract... Manaus, AM: Maloka Publicidade, 2019. p. 223-223.

    Abstract: A constante melhoria na qualidade de vida em diversos grupos de indivíduos com lesões graves se deve ao aprimoramento dos biomateriais. Avanços nas áreas de produção, desenvolvimento e caracterização de biomateriais para implantes e próteses incluem as recentes técnicas de soldagem, gravação, corte e texturização por feixe de lasers. Ensaios biomecânicos em biomateriais são importantes para se determinar níveis e limites de resistência dos mesmos. O presente trabalho avaliou a influência do processo de texturização a laser sobre o comportamento de resistência ao desgaste do aço inoxidável austenítico (SS) ISO 5832-1, mais utilizado no Brasil para a fabricação de implantes ortopédicos, no coeficiente de atrito e no volume de desgaste em testes tribológicos. A texturização aumenta a rugosidade da superfície proporcionando maior aderência entre o implante e o osso. O processo de texturização a laser foi realizado com um laser pulsado de fibra óptica, dopado com itérbio, de nanossegundos, em quatro diferentes frequências de pulso. Por razões de comparação, superfícies não tratadas também foram avaliadas. O acabamento superficial das amostras foi analisado por microscopia óptica e microscopia confocal, antes e após os ensaios. Os testes de desgaste foram realizados durante 10 min, utilizando-se como contra-corpo esferas sólidas de 52-100 aço cromado, com 2 mm de diâmetro, em equipamento tipo nanotribômetro calibrado. Os resultados indicaram que o comportamento tribológico foi influenciado pelos parâmetros do processo de texturização do laser utilizados para este biomaterial, sendo a taxa de desgaste dependente da força normal entre amostra e esfera. Palavras-chave: biomateriais, implantes, desgaste.Declaramos, para os devidos fins, que a pesquisa apresentada neste trabalho NÃO envolve “seres humanos, animais de laboratório ou animais silvestres, de forma direta ou indireta, em sua totalidade ou partes deles, incluindo o manejo de informações ou materiais”; tratando-se de pesquisa oriunda de ensaios biomecânicos em biomateriais metálicos, realizada com amostras “in vitro” de corpos-de-prova produzidos em liga de aço inoxidável para a confecção de implantes e próteses ortopédicas. Não sendo necessária a aprovação por comitês de ética em pesquisa com seres humanos ou com o uso de animais em experimentos.

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  • IPEN-DOC 27341

    ROMERO, FERNANDA C.; VICENTE, ROBERTO ; FARIAS, LUCIANA A.. Risk perception and social representation on radioactive waste: a case study with students of IPEN. In: ANNUAL WASTE MANAGEMENT CONFERENCE, 45th, March 3-7, 2019, Phoenix, Arizona, USA. Poster... 2019.

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  • IPEN-DOC 27340

    WATANABE, NAOMI ; SILVA, THALITA T. ; MARUMO, JULIO T. ; ARAUJO, LEANDRO G. de . Disposal of a pretreated oil sludge by the cementation method. In: ANNUAL WASTE MANAGEMENT CONFERENCE, 45th, March 3-7, 2019, Phoenix, Arizona, USA. Poster... 2019.

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  • IPEN-DOC 27339

    TESSARO, ANA P.G. ; ROLINDO, NATALIE C. ; MARUMO, JULIO T. ; VICENTE, ROBERTO ; LAS CASAS, ALEXANDRE . Use of ionizing radiation for treatment and extraction of organic compounds from petroleum sludge. In: ANNUAL WASTE MANAGEMENT CONFERENCE, 45th, March 3-7, 2019, Phoenix, Arizona, USA. Proceedings... Tempe, Arizona, USA: Waste Management Symposia, 2019. p. 1-7.

    Abstract: This paper presents preliminary results of a technical feasibility study of the use of an electron beam accelerator for the treatment of petroleum sludge and the degradation of organic and inorganic compounds. After analyzing the results of previous studies, the doses of the pilot study were defined.

    Palavras-Chave: chemical radiation effects; electron beams; feasibility studies; inorganic compounds; ionizing radiations; organic compounds; petroleum; radiation doses; sludges

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  • IPEN-DOC 27338

    ROLINDO, NATALIE C. ; TESSARO, ANA P.G. ; SMITH, RICARDO B. ; CAMPOS, CESAR ; SAID, YASSER ; MARUMO, JULIO T. ; VICENTE, ROBERTO . Inventory and characterization of categories 3-5 disused sealed radioactive sources. In: ANNUAL WASTE MANAGEMENT CONFERENCE, 45th, March 3-7, 2019, Phoenix, Arizona, USA. Proceedings... Tempe, Arizona, USA: Waste Management Symposia, 2019. p. 1-10.

    Abstract: Brazil has one of the biggest inventories of SRS in the world, not only because of the large industrial park, the well-developed health care infrastructure and the numerous mining operations, but also by the use of radioactive sources in consumer products, such as smoke detectors, lightning arresters, surge protectors and even cardiac pacemakers. Presently, the inventory of DSRS at the WML is of more than 10,000; if the sources from lightning arresters, smoke detectors and Ir-192 with activities above the clearance levels are included, the estimate is over 150,000. The Waste Management Laboratory (WML) of the Nuclear and Energy Research Institute (IPEN/CNEN-SP) is responsible for the management and treatment of these sources. An important aspect to consider is that Brazil does not have a defined strategy or a protocol for screening and inventorying these sources, whose management was limited only to storage. The WML started the development of methods and operational work, to characterize and reduce the total volume of this inventory for the borehole-type final disposal facility yet to be constructed, where the DSRS will be disposed of. The information available from these sources is in a database created in 1980, when the sources began to be received. Several records on the FRSD that were checked are incomplete or simply incorrect, since there is no correspondence between the dates of entry of these sources in the storage and their physical characteristics. Some reasons can be listed to try to understand the divergences: the inspection when receiving the sources was not possible, no inspection procedure was defined, there were technical difficulties to open the packages. The objective of this work is to organize the inventory in a standardized way, control access, traceability, reduction of the necessary time to locate and characterize the sources upon reception, and of the repetitive work in the operational routine, and finally release of space in the storage.

    Palavras-Chave: boreholes; inspection; iridium 192; lightning arresters; radiation sources; radioactive waste storage; smoke detectors

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  • IPEN-DOC 27337

    SMITH, RICARDO B. ; TESSARO, ANA P.G. ; ROLINDO, NATALIE C. ; VICENTE, ROBERTO . Further analyses of the unburied Goiania Accident packages. In: ANNUAL WASTE MANAGEMENT CONFERENCE, 45th, March 3-7, 2019, Phoenix, Arizona, USA. Proceedings... Tempe, Arizona, USA: Waste Management Symposia, 2019. p. 1-7.

    Abstract: In 1987, in the city of Goiania, Brazil, a derelict teletherapy machine was disassembled by scavengers and Cs-137 was released in the environment, unleashing the biggest radiological accident in Brazil. During the 15 days before the accident was acknowledged, some contaminated materials were sold and delivered to recycling factories in a few cities in the state of Sao Paulo, Brazil, in the form of metal scrap and recycled paper bales. The contaminated material was then collected, the metal scrap was conditioned in forty-three 200-liter drums, and the paper bales were stored in fifty 1.6 cubic meter steel boxes at the interim storage of the Nuclear and Energy Research Institute (IPEN), in the city of Sao Paulo, and there remained ever since. In 2017, 30 years later, initial analyses were performed at a sample of these boxes, checking for their activity, weight, and incongruences between the original values recorded at the time of collection and the measurement results 30 years later. The results indicated that none of the boxes checked were close to the clearance limit and that, without any sort of treatment, this radioactive waste should be stored for at least 150 years more. Visual inspection could not be performed at that time. Nowadays, some of the boxes were opened and samples from the contaminated material inside were taken for analysis. The main objective of this work is to report the results from the evaluation of the physical state of this material. After these analyses, the treatment options for volume reduction that were previously proposed were reviewed, and the method that best suits the current characteristics of the waste was chosen.

    Palavras-Chave: cesium 137; environment; radiation accidents; radiation hazards; radiation protection; radioactive waste storage; radioactive wastes; radiotherapy; recycling; scrap metals; steels; urban areas

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  • IPEN-DOC 27336

    SILVA, SIDNEY L. da; PRADO, FELIPE M.; TOFFOLI, DANIEL J.; WETTER, NIKLAUS U. . Measuring photoelastic dispersion coefficients in material samples with digital holography. In: BJELKHAGEN, HANS I. (Ed.) SPIE PHOTONICS WEST; SPIE OPTO, February 1-6, 2020, San Francisco, USA. Proceedings... Washington, USA: SPIE, 2020. p. 113060P-1 - 113060P-7. (Proceedings SPIE 11306, Practical Holography XXXIV: Displays, Materials, and Applications). DOI: 10.1117/12.2544874

    Abstract: Polarized Digital Holography (PHD) is a fast and efficient tool for analyzing mechanical effects in materials. Especially when the task requires non-invasive techniques that do not damage the material in study, the use of PHD has great perspectives. The most common methods of digital reconstruction use the convolution theory to discretize the Huygens- Fresnel integral. When external stresses are applied to photoelastic materials, the relationship between these stresses and phase differences observed by polarization holography is an intrinsic characteristic of the material called the photoelastic dispersion coefficient. In photoelasticity, this coefficient depends on the wavelength. By using PHD the authors show in the present paper that the photoelastic dispersion coefficient also depends on the wavelength in Holography. A Mach- Zehnder interferometer, modified with the inclusion of linear polarizers, was built to verify this effect in a sample of photoelastic material. In this set-up, two coherent light sources with different wavelengths were used. For the analysis, a digital method was created that correlated the mean stresses differences on the photoelastic material sample and the mean phases differences at each distinct wavelength.

    Palavras-Chave: interferometry; holography; stresses; polarization; photoelasticity

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  • IPEN-DOC 27335

    FREITAS, ANDERSON Z. de ; RIBEIRO, LUCAS A. de S. ; NEGRINI NETO, OSVALDO ; SARKIS, JORGE E.S. ; SIQUEIRA, ANDRESSA N. . Optical-coherence-tomography-based algorithm for handwriting forensic analysis. In: JALALI, BAHRAM (Ed.); KITAYAMA, KEN-ICHI (Ed.) SPIE PHOTONICS WEST; SPIE OPTO, February 1-6, 2020, San Francisco, USA. Proceedings... Washington, USA: SPIE, 2020. p. 112990P-1 - 112990P-8. (Proceedings SPIE 11299, AI and Optical Data Sciences). DOI: 10.1117/12.2543356

    Abstract: This work describes a new method for handwriting forensic analysis using optical coherence tomography (OCT) images. The region of interest (ROI) in documents signature to be analyzed were pre-selected with a traditional optical analyzer (Docucenter 2000 – Projectina®) equipped with different wavelengths light sources and bandpass filters coupled detector. The ROI where then submitted to OCT to 3D imaging (OCP930SR, Thorlabs Inc.) with optical resolution of 6.0 microns. One original and 5 falsified signatures were produced by 5 different individuals, using a block of 5 sheets of white sulfite paper A4 size and weight of 75 g/m^2, using the same blue ballpoint pen and in the same surface. For pressure pen calibration, were developed a system computer controlled to maintain the pressure constant during writing linear traces, 15 different pressure configuration were applied to each linear trace, resulting in a relation between deformation and applied pressure. An autonomous algorithm was developed to make surface detection, across OCT tomographic images, correct the paper surface curvature, detect and measure deformation on paper due to pen pressure, generating a new image in false color from differential pressure, based in previous calibration. This new image can be considered as a “fingerprint pressure” signature. This methodology may assist the forensic expert in correctly determining the authorship of a signature.

    Palavras-Chave: coherent radiation; tomography; crime detection; nuclear forensics; pressure measurement; hands

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  • IPEN-DOC 27334

    DIPOLD, JESSICA ; SILVA, DANILO A.A. da ; BERECZKI, ALLAN ; JIMENEZ-VILLAR, E. ; WETTER, NIKLAUS U. . Polydispersed Nd3+:YVO4+SiO2 powders for highly efficient random lasers. In: JIANG, SHIBIN (Ed.); DIGONNET, MICHEL J.F. (Ed.) SPIE PHOTONICS WEST; SPIE OPTO, February 1-6, 2020, San Francisco, USA. Proceedings... Washington, USA: SPIE, 2020. p. 112760N-1 - 112760N-8. (Proceedings SPIE 11276, Optical Components andMaterials XVII). DOI: 10.1117/12.2545028

    Abstract: Random lasers are cheap and easy to fabricate, having several different applications such as early cancer detection, encryption and Speckle-free imaging. However, few fabricated random lasers present high efficiency, which limits their possible applications. In a recent work, our group achieved a record efficiency by developing random lasers that use compacted, polydispersed yttrium vanadate doped with neodymium (Nd3+:YVO4 ) powders to create separate regions for gain and light diffusion. Large particles are responsible for the light diffusion, while the small particles that occupy the spaces between them create gain pockets, absorbing the pumped light. In this work, this strategy is refined by using passive particles (SiO2) for light diffusion, restricting the laser active particles to the gain pockets. The first attempt with this strategy used 30% of Nd3+:YVO4 small powders and 70% of large SiO2 particles. Without any further optimization, the result achieved is already 40% of the highest obtained efficiency in the previously studied Nd3+:YVO4 polydisperse sample, showing a promising result to further improve this new strategy and reach even larger efficiencies with less laser active material.

    Palavras-Chave: randomness; lasers; optical pumping; gain; absorption

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  • IPEN-DOC 27333

    WETTER, NIKLAUS U. ; SILVA, DIEGO S. da ; KASSAB, LUCIANA R.P.; ROSSI, WAGNER de . Double line Neodymium doped GeO2-PbO waveguide amplifier for the second telecom window. In: JIANG, SHIBIN (Ed.); DIGONNET, MICHEL J.F. (Ed.) SPIE PHOTONICS WEST; SPIE OPTO, February 1-6, 2020, San Francisco, USA. Proceedings... Washington, USA: SPIE, 2020. p. 112760M-1 - 112760M-7. (Proceedings SPIE 11276, Optical Components and Materials XVII). DOI: 10.1117/12.2544291

    Abstract: We report the production of active double waveguides in germanate glasses, GeO2-PbO doped with Nd3+, by direct femtosecond laser writing. The glasses were produced using the melt-quenching technique and the active waveguides were written using 30 fs laser pulses at 800 nm with different parameters of writing speeds and pulse energies depending on the rare earth elements used for doping. The photo-induced refractive index change was 5.2x10-3. The Nd doped sample exhibited a relative gain of 3.6 dB/cm for 1.6 mW of 805 nm pump power. The results obtained in present work demonstrate that Nd3+ doped GeO2-PbO glasses are promising materials for the fabrication of integrated amplifiers, lossless components and lasers based on germanate glasses.

    Palavras-Chave: optical systems; spectroscopy; amorphous state; doped materials; metallic glasses; neodymium; germanium oxides; lead oxides

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  • IPEN-DOC 27332

    BERECZKI, A. ; PAES, JOAO P.F. ; WETTER, NIKLAUS U. . Three-level Nd:YLF Raman laser directly pumped by a beam shaped diode bar. In: KUDRYASHOV, ALEXIS V. (Ed.); PAXTON, ALAN H. (Ed.); ILCHENKO, VLADIMIR S. (Ed.); ARMANI, ANDREA M. (Ed.) SPIE PHOTONICS WEST; SPIE LASE, February 1-6, 2020, San Francisco, USA. Proceedings... Washington, USA: SPIE, 2020. p. 1126614-1 - 1126614-8. (Proceedings SPIE 11266, Laser Resonators, Microresonators, and Beam Control XXII). DOI: 10.1117/12.2544844

    Abstract: Low heat generation can be obtained when pumping Nd:YLF at wavelengths of 872 nm and 880 nm and emitting at the three-level transition of 908 nm. These transitions show very low quantum defect with efficiencies of 0.96 and 0.97, respectively. However, the low average absorption cross-section at these wavelengths makes efficient absorption even for longitudinal pump setups difficult. Using a beam-shaped pump diode instead of a fiber-coupled diode bar may be an effective means of increasing absorption because it can provide for π-polarized radiation which shows higher absorption cross section. In this work, a Nd:YLF was pumped at 872 nm by a diode bar using beam-shaping. Results were compared to pumping at 872 and 880 nm with non-polarized fiber-coupled diodes. Stimulated Raman scattering was also obtained with a KGW crystal generating first Stokes emissions at 990 nm and 976 nm.

    Palavras-Chave: laser radiation; raman spectra; neodymium lasers; yttrium; lithium; beam shaping; energy levels

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  • IPEN-DOC 27331

    BERECZKI, A. ; WETTER, NIKLAUS U. . Dynamically stable lasers from commercial Nd:YAG modules with high beam quality and single-frequency: the correct choice of the fundamental waist size at the rod. In: KUDRYASHOV, ALEXIS V. (Ed.); PAXTON, ALAN H. (Ed.); ILCHENKO, VLADIMIR S. (Ed.); ARMANI, ANDREA M. (Ed.) SPIE PHOTONICS WEST; SPIE LASE, February 1-6, 2020, San Francisco, USA. Proceedings... Washington, USA: SPIE, 2020. p. 1126617-1 - 1126617-10. (Proceedings SPIE 11266, Laser Resonators, Microresonators, and Beam Control XXII). DOI: 10.1117/12.2545005

    Abstract: Diode-side pump Nd:YAG rod modules are widely available, reliable and commercially very attractive for building continuous-wave solid-state lasers in the 10-1000 W range. Newer technologies such as fiber or thin disk lasers are generally much more expensive but have the benefit of better beam quality and higher output powers if necessary. By using well-known techniques for designing dynamically stable resonators (DSRs), lasers with high extraction efficiency and high beam quality (fundamental mode, TEM00) can be obtained also with diode side-pumped modules. However, a successful project for a dynamic stable laser depends critically on the correct choice of the fundamental mode diameter within the rod. DSR design rules are based on the beam waist, w3, at the rod principal planes by considering the rod as a thin thermal lens, which differs significantly from real resonators. Here we give guidelines and criteria on how to establish the correct diameter in each case. Using off-the-shelf 75 W Nd:YAG modules it was possible to obtain linearly polarized TEM00-mode output of 30 W with M2=1.08 from a single module, M2=1.2 and 76.5 W of output power using two modules and 100.5 W of polarized, continuous output with M2=1.8. A single-frequency ring laser was also built, using two modules, generating 51.6 W of fundamental wave single-frequency output.

    Palavras-Chave: neodymium lasers; yttrium compounds; resonators; diode-pumped solid state lasers

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  • IPEN-DOC 27330

    FERREIRA, MERILYN S. ; PASK, HELEN M.; WETTER, NIKLAUS U. . Nd:YLF/KGW intracavity Raman laser in DBMC configuration at 1147 and 1163 nm in TEM00. In: CLARKSON, W. ANDREW (Ed.); SHORI, RAMESH K. (Ed.) SPIE PHOTONICS WEST; SPIE LASE, February 1-6, 2020, San Francisco, USA. Proceedings... Washington, USA: SPIE, 2020. p. 112590K-1 - 112590K-7. (Proceedings SPIE 11259, Solid State Lasers XXIX: Technology and Devices). DOI: 10.1117/12.2545092

    Abstract: A Nd:YLF / KGW intracavity Raman laser in DBMC (double-beam-mode-controlling) configuration has been investigated in this work. The fundamental wavelength laser was generated using a Nd:YLF crystal pumped in DBMC configuration generating an emission wavelength of 1053 nm in σ-polarization. A VBG (volume-Bragg-grating) equipped diode emitting at 797 nm was used as pump source. The KGW crystal has two strong Raman lines, 768 cm-1 and 901 cm-1, generating two Raman wavelengths at 1147 nm and 1163 nm, respectively. The DBMC technique allows to produce TEM00 stable output in a side-pumped configuration with no requirement to introduce any additional mode selection technique, thus achieving high efficiency for fundamental TEM00 operation. The high power density of the fundamental laser combined with intracavity Stokes conversion produces an efficient Raman laser. Allying both techniques, the Nd:YLF in DBMC configuration and the intracavity Raman generation, it was possible to generate an output power at 1163 nm of 3.2 W corresponding to a diode-to-Raman conversion efficiency of 8% with slope efficiency of 8.8 %. For the emission at 1147 nm, 3.5 W of output power was achieved with a diode-to-Raman conversion efficiency of 11% and slope efficiency of 9%. The beam quality was M2 =1.9 and 1.1 in the horizontal and vertical direction, respectively. This is, to our knowledge, the first report of a side-pumped Nd:YLF/KGW intracavity Raman laser in DBMC configuration.

    Palavras-Chave: raman spectra; raman effect; optical pumping; diode-pumped solid state lasers

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  • IPEN-DOC 27329

    NOGUEIRA, K.M. ; VARCA, J.O. ; LIMA, C.S.A. ; VARCA, G. ; LUGAO, A.B. ; FREITAS, L.F. . The effects gamma radiation dose on the swelling capacity of PVP/lignin hydrogels dressings for wound treatment. In: WORKSHOP DE BIOMATERIAIS, ENGENHARIA DE TECIDOS E ORGÃOS ARTIFICIAIS, 6th, October 29-31, 2019, São Paulo, SP. Abstract... 2019. p. 246-246.

    Abstract: Lignin is a carbon renewable source and has been widely explored in different areas in the last years, especially in the biomaterials field as dressings and other biomedical devices due its natural origin and low cost (1). Its chemical structure confers important properties to this macromolecule such as antioxidant capacity, UV protection and bactericidal activity (2,3). Polivinylpirrolidone (PVP) is a polymer widely applied for biomedical applications due to its relevant properties, such as the water absorption capacity, suitable mechanical properties for wound healing applications, and the capacity to originate hydrogels with different characteristics (4). Gamma radiation is a relevant option to produce biomedical devices, as the technology allows polymer crosslinking and sterilization in a single step (5). Two polymer solutions were prepared, PVP 10% (w, v) in distiled water (neutral pH) with poly(ethylene glycol) diacrylate (1.0% w/v) and lignin 6% (w, v) (pH > 13) and homogenized separately, until complete dissolution. The solutions were mixed in the follow ratios 95/5, 90/10 and 80/20, in which were added to a 2% (w, v) of agar and mixed at 70 ºC for 30 minutes. Samples were disposed in glass moulds and irradiated at 25, 50 and 100 kGy at dose rate of 5 kGy/h in a 60Co irradiator. Samples assessed by autoclave presented higher swelling than the PVP control, but lower gel fraction in comparison with the standard, except for formulation 90:10. Swelling and Gel Fraction were also evaluated by shaker at 37 ºC for 24 h. The results showed that the increase of dose decrease the swelling capacity and gel fraction decrease with the increase of lignin in the formulations. In general, the hydrogels irradiated at 25 and 50 kGy, except for formulation 80:20 at 25 kGy, presented good integrity and suitable results to be considered for the next steps of the study and are promising for biomedical application.

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  • IPEN-DOC 27328

    DE FREITAS, L.F. ; DA CRUZ, C.C. ; VARCA, G. ; LUGAO, A.B. . The presence or absence of ethanol in radiolytic synthesis medium leads to different kinds of hybrid papain-gold nanoparticles. In: WORKSHOP DE BIOMATERIAIS, ENGENHARIA DE TECIDOS E ORGÃOS ARTIFICIAIS, 6th, October 29-31, 2019, São Paulo, SP. Abstract... 2019. p. 27-27.

    Abstract: Gold nanoparticles are widely used for a plethora of applications, however, the short and long term environmental impacts of those nanoparticles when they reach the soil, rivers, and sea have just recently been taken into consideration. Novel synthetic routes have been developed without the use of toxic reducing or capping agents so that the products are biocompatible and environment-friendly, in the so-called Green Nanotechnology. One of these methods is the radiolytic synthesis using gamma radiation, which does not require the use of any reducing agent. Different conditions in the synthesis medium can lead to different products, therefore the aim of this study was to investigate the effect of the presence of ethanol on the nanoparticles generated via radiolysis using gamma radiation. The synthesis medium consisted on a mixture of NaAuCl4 (5 x 10-4 mol L-1), isopropanol (0.2 mol-1); and papain as a stabilizer and coating agent (1 mg mL-1), with or without the presence of 20% ethanol. The samples were irradiated with 10 kGy in a gamma multipurpose irradiator (60Co source) and stored at 4 ºC until use. Their hydrodynamic diameter and zeta potential was assessed with a Zetasizer Nano ZS90 device (Malvern Instruments UK), and images of transmission electron microscopy (TEM) were taken in order to observe the real size and morphology of the nanoparticles in a 40,000X magnification. The presence of ethanol indeed leads to different kinds of nanoparticles. Their hydrodynamic diameter was 8.773 ± 2.3 nm (papain-AuNPs without ethanol) and 9.976 ± 2.9 nm (papain- AuNPs with 20% ethanol), and their zeta potentials were 34.4 ± 4,2 mV and 25.3 ± 3.58 mV, respectively. The TEM images revealed that when ethanol is absent, the nanoparticles formed consist on a gold core (approximately 5 nm in diameter) with papain coating. When ethanol is present, though, the nanoparticles consist on a papain core (approximately 10 nm) decorated with smaller gold nanoparticles. In conclusion, both protocols lead to stable nanoparticles with good control of size, especially in the absence of ethanol, but according to the desired applications, ethanol can be useful for the generation of nanoparticles with higher enzymatic activity from papain, i.e. proteolytic and permeation-enhancing activities.

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  • IPEN-DOC 27327

    BALOGH, T.S. ; KADLUBOWSKI, S.; BONTURIM, E. ; VARCA, G. ; LUGAO, A.B. . Synthesis and characterization of PVP nanogels prepared by gamma radiation using 60Co source. In: WORKSHOP DE BIOMATERIAIS, ENGENHARIA DE TECIDOS E ORGÃOS ARTIFICIAIS, 6th, October 29-31, 2019, São Paulo, SP. Abstract... 2019. p. 245-245.

    Abstract: Nanogels are promising and innovative systems in nanometer scale, with particle size range varying from 0 to 100 nm, of great potential in nanomedicine, pharmaceutics and bionanotechnology. They present several advantages such as capacity of injection into the circulation reaching target tissues and ability to deliver their payloads locally and intracellularly. Nanogels are defined as two-component system on nanometer scale consisting of a permanent three-dimensional network of linked polymer chains, and molecules of a solvent filling the pores of this network. They are formed by intramolecular crosslinking that can be achieved by the use of ionizing radiation, this method allows the formation of nanogels free of additives, rendering them non-toxic, a fundamental requirement for biomedical application. In this work, five samples of nanogels were developed using a 25 mM PVP solution. The samples were saturated with argon and prepared in multipurpose cobalt-60 gamma irradiator using doses of 1, 2, 5, 10 and 25 kGy at a dose rate of 10 kGy/hour corresponding, respectively, to samples A, B, C, D and E. These samples were morphologically characterized using atomic force microscopy (AFM) as well as the pristine PVP solution. The mean particle size of the samples as well as the determination of polydispersity index was performed in equipment Zetasizer Nano ZS - Malvern® and the determination of radius of gyration and molecular weight was realized in equipment Heleos - Wyatt®. The mean particle size of the samples A, B, C, D and E, were, respectively, 41.89, 46.85, 61.04, 62.79 and 62.11 nm and the mean particle size of the pristine PVP solution was 43.28 nm. The AFM results revealed the presence of spherical nanostructures in the samples prepared with dose equal to or more than 5 kGy (samples C, D and E). Under the conditions evaluated in the study the morphological characterization of the nanogels revealed that the doses of 5 kGy, 10 and 25 kGy are the most suitable doses for the nanogel formation as it led to spherical structures when compared to the other conditions assayed.

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  • IPEN-DOC 27326

    LIMA, C.S.A. ; VARCA, G. ; DE FREITAS, L.F. ; VARCA, J.O. ; LUGAO, A.B. . Natural polymer hydrogels with gold nanoparticles for bladder cancer chemotherapy delivery. In: WORKSHOP DE BIOMATERIAIS, ENGENHARIA DE TECIDOS E ORGÃOS ARTIFICIAIS, 6th, October 29-31, 2019, São Paulo, SP. Abstract... 2019. p. 127-127.

    Abstract: The treatment of bladder cancer is done by transurethral resection for tumor removal, followed by immune or chemotherapy intravesical, according to the stage of the disease. The main objective of this work was to develop and characterize strategies to increase the residence time and specificity of chemotherapy through the application of hydrogels for chemotherapy and /or immunotherapy administration. Natural polymers gellan gum and microcrystalline cellulose were chosen to prepare the hydrogels as they are already widely used in the biomedical area due to characteristics such as the absence of toxicity, high biocompatibility, and biodegradability. Papain-coated gold nanoparticles were added to the gels to promote chemo or immunotherapeutic permeation. Preliminary stability assays were carried out to evaluate the compatibility between the polymeric matrices and the gold nanoparticles. The systems were characterized by Scanning Electron Microscopy, and Fourier Transform Infrared Spectroscopy. The results allowed the identification of the polymer groups present in the formulations, as well as the evaluation of the interactions between the hydrogel network and the nanoparticles. The formulations were suitable for the proposed application.

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  • IPEN-DOC 27325

    BATISTA, J.G.S. ; LUGAO, A.B. ; DA CRUZ, C.C. ; DE FREITAS, L.F. ; SANTOS, L.O. ; RODRIGUES, A.S. . Nanotecnologia verde: síntese de nanopartículas de ouro utilizando extrato de Annona muricata L.. In: WORKSHOP DE BIOMATERIAIS, ENGENHARIA DE TECIDOS E ORGÃOS ARTIFICIAIS, 6th, October 29-31, 2019, São Paulo, SP. Abstract... 2019. p. 29-29.

    Abstract: O câncer está entre as doenças com maior índice de mortalidade, com mais de 100 tipos diferentes ocorrendo devido a mutações no material genético das células. É a terceira principal causa de morte em todo o mundo após doenças cardiovasculares e infecciosas. Além disso, percebe-se cada vez mais que muitas das doenças se devem ao “estresse oxidativo” que resulta de um desequilíbrio entre a formação e a neutralização de espécies oxidantes. O estresse oxidativo é iniciado pelos radicais livres, que buscam estabilidade através do pareamento de elétrons com macromoléculas biológicas, como proteínas, lipídios e DNA, em células humanas saudáveis e causam danos às proteínas e ao DNA, juntamente com a peroxidação lipídica. Essas mudanças contribuem para o câncer, aterosclerose, doenças cardiovasculares, envelhecimento e doenças inflamatórias. Todas as células são expostas ao estresse oxidativo e, portanto, a oxidação e os radicais livres desempenham um papel importante no desenvolvimento do câncer e na carcinogênese.Portanto, ainda estão sendo feitos esforços para procurar substâncias eficazes que ocorrem naturalmente e que possam impedir, desacelerar ou reverter o desenvolvimento do câncer. Plantas medicinais têm um lugar especial na gestão do câncer. Diversos estudos de pesquisa sobre o câncer foram realizados utilizando plantas medicinais tradicionais, em um esforço para descobrir novos agentes terapêuticos que não possuem efeitos secundários associados aos presentes agentes quimioterápicos. Estudos utilizando extrato de Annona muricata L., popularmente conhecida como araticum, demonstraram potencial ação anti-inflamatória e anticâncer, devido suas propriedades antioxidante e imunológica. O objetivo do presente trabalho foi sintetizar nanopartículas de ouro utilizando o extrato seco de Annona muricata L. e verificar suas propriedades físico-químicas, como tamanho, formato e estabilidade. E assim unir as propriedades do araticum com as das nanopartículas de ouro que possuem aplicações na terapia e diagnóstico de câncer. Os resultados obtidos, demonstram que é possível sintetizar nanopartículas de ouro com potencial aplicação na medicina utilizando o extrato de araticum. A caracterização foi realizada por meio das técnicas de espectrofotometria UV-Vis, espalhamento de luz dinâmico (DLS), microscopia eletrônica de transmissão (TEM). O estudo de estabilidade in vitro foi realizado misturando-se a solução de nanopartículas de ouro com NaCl, histidina, cisteína, BSA, pH 5, 7 e 9. As nanopartículas apresentaram tamanho médio de 15 nm por TEM e tamanho hidrodinâmico médio de 30 nm por DLS. No teste de estabilidade in vitro, as nanopartículas de ouro sintetizadas com o extrato seco de araticum apresentaram estabilidade em todos os meios testados por até 14 dias, não havendo diminuição na absorbância no comprimento de 525 nm, que é característico do dipolo gerado pela ressonância plasmônica de superfície em nanopartículas de ouro.

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  • IPEN-DOC 27324

    SILVA, C.A.J. ; BRAGUIN, L.N.M. ; VIVEIROS, B.G. ; BERBEL, L.O. ; ROSSI, J.L. ; COSTA, I. ; SAIKI, M. . Estudo do comportamento frente à corrosão da liga de magnésio AZ31 de uso em implantes temporários utilizando soluções simuladoras de fluidos corpóreos. In: WORKSHOP DE BIOMATERIAIS, ENGENHARIA DE TECIDOS E ORGÃOS ARTIFICIAIS, 6th, October 29-31, 2019, São Paulo, SP. Abstract... 2019. p. 158-158.

    Abstract: Atualmente, ligas de magnésio estão ganhando grande interesse para aplicações médicas devido a sua propriedade de degradação no corpo humano, principalmente para aplicações de interesse como stents cardiovasculares e próteses ortopédicas. Estes implantes temporários fornecem uma estabilidade mecânica necessária para o reparo e corroem completamente após o tempo de vida útil e fim do tratamento. Contudo, uma dificuldade na aplicação destes materiais na indústria de biomateriais é a corrosão antecipada e precoce à cura celular. Amostras da liga de magnésio AZ31 foram cortadas em lascas e a técnica escolhida para análise química elementar foi a Análise por Ativação com Nêutrons (NAA). Irradiações de curta e longa duração foram realizadas nas amostras juntamente com padrões sintéticos no reator IEA-R1 em um fluxo de nêutrons térmicos abaixo de 4,0x1012 n cm-2s-1. Concentrações dos elementos As, La, Mg, Mn, Na, Sb e Zn foram determinadas na liga AZ31, calculadas pelo método comparativo. Para os ensaios de corrosão, as amostras foram limpas com álcool etílico, acetona e água purificada MilliQ por agitação ultrassônica, e, em seguida foram lixadas com lixas de SiC com granulometria de #500, #800, #1200, #2000 e #4000. Testes de visualização em ágar-ágar e imersão foram realizados em solução de cloreto de sódio 0,90 % (massa), solução tampão de fosfato (PBS) e solução simuladora de fluidos corpóreos (SBF) utilizando fenolftaleína como indicador ácido-base. A observação das superfícies das amostras, antes e após exposição às soluções, foi realizada por microscopia óptica (MO) e microscopia eletrônica de varredura (MEV). A superfície também foi observada após remoção dos produtos de corrosão por desmutting e irradiação para análise quantitativa pela técnica NAA. Visualizações em gel ágarágar revelaram aumento do pH local proveniente da liberação de íons hidroxila da reação catódica e menor liberação de íons ocorreu em SBF em comparação às soluções de NaCl e PBS. As micrografias da superfície evidenciaram a formação instantânea de uma camada de produtos de corrosão após uma hora de ensaio e o desmutting revelou microcavidades caracterizadas por pites.

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  • IPEN-DOC 27323

    BRAGUIN, L.N.M. ; SILVA, C.A.J. ; BERBEL, L.O. ; COSTA, I. ; SAIKI, M. . Estudo da resistência à corrosão do aço inoxidável austenítico ISO 5832-1 utilizado como implante ortopédico. In: WORKSHOP DE BIOMATERIAIS, ENGENHARIA DE TECIDOS E ORGÃOS ARTIFICIAIS, 6th, October 29-31, 2019, São Paulo, SP. Abstract... 2019. p. 156-156.

    Abstract: O aço inoxidável austenítico ISO 5832-1 utilizado como biomaterial é muito aplicado na área de ortopedia, especialmente na fabricação de implantes, como substituição temporária ou permanente de estruturas ósseas. Este aço apresenta biocompatibilidade, alta resistência mecânica, resistência à corrosão e baixo custo quando comparado a outros biomateriais, como ligas de titânio e de Cr-Co. O objetivo deste estudo foi avaliar a resistência à corrosão localizada do aço inoxidável ISO 5832-1 utilizado em implantes ortopédicos por ensaios eletroquímicos em duas soluções diferentes. Este estudo é de grande interesse para avaliar a corrosão dos implantes metálicos que podem prejudicar a estrutura do biomaterial e liberar produtos de corrosão nos fluidos corpóreos causando possíveis reações biológicas adversas. A determinação dos elementos químicos da composição do aço inoxidável austenítico ISO 5832- 1 foi realizada por análise por ativação com nêutrons (NAA). Para estas análises foram obtidas lascas deste material. Cerca de 50 mg de amostra foram pesadas em envelopes de polietileno e irradiados junto com padrões sintéticos de elementos. Irradiações de curta e longa duração foram realizadas no reator nuclear de pesquisa, IEA-R1, utilizando um fluxo de neutrons térmicos de cerca de 4,5 x 10^12 n cm^-2 s^-1. Para os ensaios eletroquímicos, as amostras de liga foram lixadas com lixas de SiC de granulometria #320, #500, #1200, #2000 e #4000 e polidas com pasta de diamante de 1μm. As medidas de potencial de circuito aberto e polarização potenciodinâmica catódica e anódica foram realizadas em solução de 0,90 % (massa) de NaCl e de solução simuladora de fluido corpóreo (SBF). A alta resistência à corrosão deste aço foi atribuída à formação de filme de óxido passivo que reduz a taxa de corrosão, dificultando o transporte de íons metálicos e de elétrons, que provocam a possível liberação de íons tóxicos para o corpo humano.

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  • IPEN-DOC 27322

    ALCANTARA, M.T.S. ; OLIVEIRA, M.J.A. ; LIERMANN, G.M. ; LUGAO, A.B. . Efeito do CMC no intumescimento de curativos de hidrogel à base de PVP com nanoprata. In: WORKSHOP DE BIOMATERIAIS, ENGENHARIA DE TECIDOS E ORGÃOS ARTIFICIAIS, 6th, October 29-31, 2019, São Paulo, SP. Abstract... 2019. p. 48-48.

    Abstract: Hidrogéis de PVP são redes poliméricas tridimensionais, hidrofílicas, que apresentam propriedades de intumescimento e biocompatibilidade o que favorece seu uso como curativos. Por propiciar umidade no leito da ferida mantém o ambiente ideal para cicatrização, além de não aderir a ela. Por outro lado as nanopartículas de prata apresentam propriedades antimicrobianas e antiinflamatórias e o uso de radiação ionizante permite a reticulação e esterilização simultânea do curativo. O objetivo deste estudo foi avaliar o efeito do CMC no intumescimento de curativos de hidrogel com 22 e 80 ppm de nanopartículas de prata, reticulado por radiação ionizante, assim como avaliar a resistência mecânica dos curativos estudados. Os curativos foram avaliadas a partir de ensaios de fração gel, intumescimento e resistência mecânica. Os resultados indicaram um aumento importante no intumescimento do curativo com a adição de CMC, principalmente para o curativo com maior concentração de nanoprata, porém um menor grau de reticulação e consequentemente redução da sua resistência mecânica.

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  • IPEN-DOC 27321

    MAZIERO, J.S. ; ROGERO, S.O. ; DAMASCENO, K.C. ; ORMENIO, M.B. ; CAVALCANTE, A.K. ; MARTINI, G.A. ; BATISTA, J.G.S. ; KATTI, K.V.; LUGAO, A.B. ; ROGERO, J.R. . Avaliação da toxicidade de nanopartículas de prata estabilizadas com goma arábica. In: WORKSHOP DE BIOMATERIAIS, ENGENHARIA DE TECIDOS E ORGÃOS ARTIFICIAIS, 6th, October 29-31, 2019, São Paulo, SP. Proceedings... 2019. p. 403-413.

    Abstract: As nanopartículas de prata (NPAg), devido a seus diversos atributos (formato variado, elevada área superficial e alto poder bactericida), vem sendo amplamente utilizadas em diversos setores da indústria. Esta utilização abrangente, tem provocado grande preocupação, quanto aos impactos e riscos potenciais que as NPAg podem causar ao meio ambiente e à saúde humana. Este trabalho teve como objetivo verificar a toxicidade de uma amostra de NPAg estabilizada com Goma Arábica e reduzida com Tri-Alanina, utilizando ensaios in vitro e in vivo. O teste in vitro de citotoxicidade, foi realizado seguindo a norma ISO 10993 - 5, em células da linhagem NCTC-L929; os ensaios in vivo de ecotoxicidade aguda, de acordo com a norma brasileira ABNT NBR 12713, utilizando como organismo teste a Daphnia similis; e embriotoxicidade aguda de acordo com o protocolo da OECD 236, utilizando como organismo teste o Danio rerio. Os resultados obtidos foram: IC50 de 2,61 mg L-1, CE50 de 6,55 μg L-1 e CL50 de 673 μg L-1. Os organismos aquáticos apresentaram maior sensibilidade às NPAg do que as células em cultura, elevando a importância de se realizar mais estudos em várias espécies de interesse biológico. Além disso, mostra-se necessário verificar o descarte apropriado dessas nanopartículas, visto que no Brasil ainda não há legislações que quantifiquem os limites permissíveis para esse descarte.

    Palavras-Chave: fishes; seafood; gum acacia; daphnia; silver; nanoparticles; toxicity

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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.