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  • IPEN-DOC 27471

    COSTA, ANDREA da; NASCIMENTO, NANCI do ; GALISTEO JUNIOR, ANDRES J.; PASSOS, ALINE B.D. dos; ANDRADE JUNIOR, HEITOR F. de. Radiation effects on Toxoplasma antigens: different immune responses of irradiated intact tachyzoites or soluble antigens in experimental mice models. International Journal of Radiation Biology, v. 96, n. 5, p. 697-706, 2020. DOI: 10.1080/09553002.2020.1704298

    Abstract: Purpose: Purpose: Protein irradiation causes aggregation, chain breakage, and oxidation, enhancing its uptake by antigen-presenting cells. To evaluate if irradiated proteins participate on the protection, we studied the immune response induced in mice immunized with irradiated soluble extracts of T. gondii tachyzoites (STag) or irradiated intact T. gondii RH tachyzoites (RH0.25 kGy). Material and Methods: Soluble extracts of Toxoplasma gondii tachyzoites (STag) were irradiated at different dose by Cobalt-60 source. By polyacrylamide gel electrophoresis (SDS-Page) we evaluated the effects on primary structures of protein STags induced by irradiation. By Enzyme-linked Immunosorbent Assay (ELISA) we evaluated the difference between humoral immune response induced by irradiated STag or RH tachyzoites in immunized mice from the detection of specific immunoglobulin G (IgG) antibodies in the serum of immunized mice. From challenge with viable RH strain of T. gondii we evaluated the protection induced in the immunized animals. By cytometry we performed the phenotyping of T and B lymphocytes in the peripheral blood of the immunized animals. Results: Irradiation dose of 1.5 kGy induced minimal changes in most proteins, without affecting their antigenicity or immunogenicity. Immunization showed saturation at the dose of 10 µg/mice, with worst response at higher doses. STag irradiated at 1.5  kGy (STag1.5 kGy) induced higher survival and protection similar to T. gondii RH strain irradiated at 0.25 kGy (RH0.25 kGy), with higher serum levels of high affinity IgG compared to STag native. Blood immune memory cells of mice immunized with STag1.5 kGy had higher proportions of CD19+ (cluster of differentiation 19) and CD4+ (cluster of differentiation 14) cells, whereas mice RH0.25 kGy had high proportion of memory CD8+ (cluster of differentiation 8) cells. Conclusions: Our data suggest that major histocompatibility complex type I (MHCI) pathway, appears seem to be used by RH0.25 kGy to generate cytotoxic cells while STag1.5 kGy uses a major histocompatibility complex type II (MHCII) pathway for B-cell memory, but both induce sufficient immune response for protection in mice without any adjuvant. Irradiation of soluble protein extracts enhances their immune response, allowing similar protection against T. gondii in mice as compared to irradiated intact parasites.

    Palavras-Chave: protozoa; parasites; parasitic diseases; gamma radiation; radiation effects; vaccines; immunity; ionizing radiations; cobalt 60; antigens; mice

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  • IPEN-DOC 27440

    BUSTILLOS, OSCAR V. . Espectrometria de massas com plasma acoplado indutivamente ICP-MS. Revista Analytica, v. 109, p. 31-33, 2020.

    Palavras-Chave: mass spectroscopy; plasma; icp mass spectroscopy; absorption spectroscopy; atomic ions; atoms

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  • IPEN-DOC 27439

    BUSTILLOS, OSCAR V. . Espectrometria de massas por tempo de voo TOF-MS. Revista Analytica, v. 108, p. 26-27, 2020.

    Palavras-Chave: mass spectroscopy; time-of-flight mass spectrometers; ions; time measurement; mass number

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  • IPEN-DOC 27438

    BUSTILLOS, OSCAR V. . Processamento de dados na espectrometria de massas. Revista Analytica, v. 107, p. 24-25, 2020.

    Palavras-Chave: mass spectroscopy; data processing; computer codes; leak detectors; programming

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  • IPEN-DOC 27437

    BUSTILLOS, OSCAR V. . A cromatografia líquida acoplada à espectrometria de massas Tandem HPLC-MS/MS. Revista Analytica, v. 106, p. 34-35, 2020.

    Palavras-Chave: chromatography; high-performance liquid chromatography; mass spectroscopy; ions; chemical analysis

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  • IPEN-DOC 27436

    BUSTILLOS, OSCAR V. . A cromatografia a gás acoplada à espectrometria de massas - GC/MS. Revista Analytica, v. 105, p. 28-30, 2020.

    Palavras-Chave: mass spectroscopy; gas chromatography; physical chemistry; separation processes; ion sources

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  • IPEN-DOC 27435

    BUSTILLOS, OSCAR V. . O sistema de vácuo na espectrometria de massas. Revista Analytica, v. 104, p. 22-23, 2020.

    Palavras-Chave: mass spectroscopy; vacuum systems; baking; control systems; atoms

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  • IPEN-DOC 27434

    NASCIMENTO, SERGIO F. do ; RODAS, ANDREA C.D.; CARVALHO, FLAVIO M. de S.; HIGA, OLGA Z. ; SILVA, CECILIA C.G. e . Influence of silicon, strontium and aluminum oxides on silicon nitride ceramics for bone replacements. Revista Matéria, v. 25, n. 4, 2020. DOI: 10.1590/S1517-707620200004.1178

    Abstract: Although silicon nitride ceramics have been shown very propitious to be used for bone replacements, some characteristics can be controlled to improve their osseointegrations process. One of them is the intergranular phase whose composition can be specified to stimulate mineralization and osteoblastic production. In this paper, the intergranular glassy phase was projected in order to contain silicon, strontium and aluminum oxides. Silicon nitride samples containing different contents of SiO2, SrO and Al2O3 were sintered at 1815oC for 1 hour and characterized by scanning electron microscopy and X-ray diffraction. Hardness and fracture toughness were determined by Vickers hardness test and compressive strength was evaluated using an universal material testing machine. The biological behavior was studied in regard to cytotoxicity and cell proliferation by means of in vitro experiments. The samples reached high densities (higher than 95 %TD), total α→β-Si3N4 transformation, fracture toughness higher than 6.5 MPa.m1/2, compressive strength up to 2500 MPa and Vickers hardness less than 9.8 GPa. All samples were non-cytotoxic and able to promote cell proliferation with great potential to be used as components for bone replacements. However, that sample with high content of strontium had the best results of cell proliferation, proving the importance of a careful choice of intergranular phase composition in silicon nitride ceramics.

    Palavras-Chave: silicon nitrides; strontium oxides; aluminium oxides; silicon oxides; ceramics; skeleton; connective tissue cells; mechanical properties; microstructure; toxicity; cell proliferation

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  • IPEN-DOC 27433

    DE PRETTO, LUCAS R. ; AMARAL, MARCELO M.; FREITAS, ANDERSON Z. de ; RAELE, MARCUS P. . Nondestructive evaluation of fused filament fabrication 3D printed structures using optical coherence tomography. Rapid Prototyping Journal, v. 26, n. 10, p. 1853-1860, 2020. DOI: 10.1108/RPJ-12-2019-0314

    Abstract: Purpose – The quality of components under fused filament fabrication (FFF) is related to the correct filament spacing and bonding of successively deposited layers and is evaluated mainly by scanning electron microscopy (SEM). However, it is a destructive technique and real-time evaluation is not possible. Optical coherence tomography (OCT), on the other hand, is an optical method that acquires cross-sectional images non-invasively and in real-time. Therefore, this paper aims to propose and validate the use of OCT as a non-destructive quality evaluation tool for FFF using Polylactic Acid (PLA) filaments. Design/methodology/approach – PLA three-dimensional (3D) printed samples were made in a variety of nozzle temperatures and mesh spacing. These samples were fractured in liquid nitrogen and inspected using SEM (as a gold standard) to evaluate dimensions and morphology, then the samples were evaluated by OCT in the same area, allowing the results confrontation. Findings – Our results indicate a good correlation between OCT and SEM for the dimensional assessment of layers. When the filament was extruded in lower temperatures, the OCT images presented sharply defined interfaces between layers, in contrary to higher nozzle temperatures, denoting better fusion between them. However, higher extruding temperatures are incurred in greater deviations from nominal dimensions of the mesh. Finally, we demonstrate the advantage of a full 3D tomographic reconstruction to inspect within a FFF sample, which enabled the inspection of “hidden” information, not visible on a single cross-sectional cut. Originality/value – This paper proposes OCT as a novel and nondestructive evaluation tool for FFF.

    Palavras-Chave: nondestructive analysis; filaments; fabrication; tomography; adhesion; three-dimensional calculations; coherence length; scanning electron microscopy; deposition; simulation

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  • IPEN-DOC 27432

    ASFORA, VIVIANE K.; BUENO, CARMEN C. ; BARROS, VINICIUS M. de; KHOURY, HELEN; VAN GRIEKEN, RENE. X-ray spectrometry applied for characterization of bricks of Brazilian historical sites. X-Ray Spectrometry, v. 50, n. 1, p. 45-52, 2021. DOI: 10.1002/xrs.3194

    Abstract: This paper presents the results of X-ray fluorescence (XRF) analysis of bricks sampled from historical places in Pernambuco, a state in the northeastern region of Brazil. In this study, twenty bricks found in historical sites were analyzed. Two bricks made in the 17th century, presumably used as ballast in ships coming from Holland, five locally manufactured bricks: one from 18th century, three from 19th century, and one from 20th century, and thirteen bricks collected from a recent Archeological investigation of Alto da Sé, in the town of Olinda. Qualitative determination of the chemical elements present in the samples was undertaken using a self-assembled portable XRF system based on a compact X-ray tube and a thermoelectrically cooled Si-PIN photodiode system, both commercially available. X-ray diffraction analysis was also carried out to assess the crystalline mineral phases present in the bricks. The results showed that quartz (SiO2) is the major mineral content in all bricks. Although less expressive in the XRD patterns, mineral phases of illite, kaolinite, anorthite, and rutile are also identified. The trace element distribution patterns of the bricks, determined by the XRF technique, is dominated by Fe and, in decreasing order, by K, Ti, Ca, Mn, Zr, Rb, Sr, Cr, and Y with slight differences among them. Analyses of the chemical compositional features of the bricks, evaluated by principal component analysis of the XRF datasets, allowed the samples to be grouped into five clusters with similar chemical composition. These cluster groups were able to identify both age and manufacturing sites. Dutch bricks prepared with different geological clays compositions were defined.

    Palavras-Chave: archaeology; archaeological sites; building materials; bricks; manufacturing; construction; x-ray fluorescence analysis

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  • IPEN-DOC 27431

    TAMAGAWA, HIROHISA; MULEMBO, TITUS; LIMA, VERA M.F. de ; HANKE, WOLFGANG. GHK eq. and HH eq. for a real system is mathematically associable to each other but their physiological interpretation needs a reconsideration. Progress in Biophysics and Molecular Biology, v. 158, p. 4-15, 2020. DOI: 10.1016/j.pbiomolbio.2020.07.008

    Abstract: Despite the long and broad acceptance of the Goldman - Hodgkin - Katz equation (GHK eq.) and the Hodgkin - Huxley equation (HH eq.) as strong tools for the quantitative analysis of the membrane potential behavior, for a long time they have been utilized as separate concepts. That is the GHK eq. and the HH eq. have not been associated with each other mathematically. In this paper, an attempt to associate these equations to each other mathematically was demonstrated and was successful by viewing the system in question as a thermodynamically real system rather than an ideal system. For achieving that, two fundamental physical chemistry concepts, the mass action law, and the Boltzmann distribution were employed. Hence, this paper’s achievement is completely within the framework of common thermodynamics. Through this work, the origin of the membrane potential generation attributed to the ion adsorption-desorption process and governed by the mass action law and the Boltzmann distribution is expressed to be plausible, whereas the existing membrane potential generation mechanism states that membrane potential is generated by transmembrane ion transport. As at this moment, this work does not intend to deny the transmembrane ion transport as a membrane potential generation mechanism but urges the readers to reconsider its validity, since this work suggests that the ion adsorptiondesorption mechanism is as plausible as the transmembrane ion transport mechanism as a cause of membrane potential generation.

    Palavras-Chave: cell membranes; electric potential; physiology; mass; boltzmann equation; boltzmann statistics; adsorption; desorption; ions

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  • IPEN-DOC 27430

    ARAUJO, JOAO V. de S. ; MILAGRE, MARIANA X. ; FERREIRA, RAPHAEL O.; MACHADO, CARULINE de S.C. ; BUGARIN, ALINE de F.S. ; MACHADO, IZABEL F.; COSTA, ISOLDA . Exfoliation and intergranular corrosion resistance of the 2198 Al–Cu–Li alloy with different thermomechanical treatments. Materials and Corrosion, v. 71, n. 12, p. 1957-1970, 2020. DOI: 10.1002/maco.202011839

    Abstract: In this study, the resistance to exfoliation and intergranular corrosion (IGC) of the 2198 Al–Cu–Li alloy submitted to different thermomechanical treatments (T3, T8, and T851) was investigated. The tests were carried out following the standard practices, ASTM G34‐18 and ASTM G110‐15, respectively. All the tested alloys showed susceptibility to exfoliation and some alloys showed susceptibility to IGC, but the artificially aged alloys presented a higher tendency to exfoliation. The extensive hydrogen evolution reaction (HER) was observed on the surfaces of artificially aged alloys when immersed in the EXCO solution. The HER resulted in an increase in solution pH with the time of immersion. Also, the weight losses related to the artificially aged alloys were higher than that of the naturally aged ones. The T8 treatment was the only condition that resulted in susceptibility to both, intergranular and transgranular corrosion, whereas the T851 treatment did not show IGC susceptibility, only transgranular corrosion. Finally, the 2198‐T3 condition showed the highest corrosion resistance among the thermomechanical treatments tested. The results of the 2198 alloy subjected to various treatments were compared with that of the 2024‐T3 alloy. This last alloy showed higher resistance to exfoliation and IGC as compared with the 2198 alloy.

    Palavras-Chave: corrosion; corrosion resistance; intergranular corrosion; thermomechanical treatments; aluminium alloys; copper alloys; lithium alloys; optical systems; emission spectroscopy; plasma; friction welding

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  • IPEN-DOC 27429

    GERALDO, BIANCA ; ARAUJO, LEANDRO G. de ; VICENTE, ROBERTO ; TADDEI, MARIA H.T.; CHEBERLE, SANDRA M.; MARUMO, JULIO T. . Radioanalytical methods for sequential analysis of actinide isotopes in activated carbon filter‑bed waste. Journal of Radioanalytical and Nuclear Chemistry, v. 326, p. 1559-1568, 2020. DOI: 10.1007/s10967-020-07435-8

    Abstract: In this work, we compare methods for the sequential determination of U and the transuranium elements Np, Pu, Am, and Cm. The chemical yield, the time spent in the analysis, the amount of secondary waste, and the costs of each method are the aspects of interest. Two methods were compared: extraction chromatography (EC) and ion exchange plus extraction chromatography (IE + EC). The chemical yields of (EC) and (IE + EC) were similar for all radionuclides. The (EC) method is the more effective with respect to time of analysis, the amount of secondary waste and costs.

    Palavras-Chave: radioisotopes; radiochemistry; cost benefit analysis; ion exchange; radiopharmaceuticals; tracer techniques

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  • IPEN-DOC 27428

    CAVALLARO, M.; ACOSTA, L.; ADSLEY, P.; AGODI, C.; ALTANA, C.; AMADOR-VALENZUELA, P.; AUERBACH, N.; BAREA, J.; BELLONE, J.I.; BIJKER, R.; BORELLO-LEWIN, T.; BOZTOSUN, I.; BRANCHINA, V.; BRASOLIN, S.; BRISCHETTO, G.A.; BRUNASSO, O.; BURRELLO, S.; CAMPAJOLA, L.; CALABRESE, S.; CALABRETTA, L.; CALVO, D.; CAPIROSSI, V.; CAPPUZZELLO, F.; CARBONE, D.; CHARON GARCIA, L.E.; CHÁVEZ LOMELI, E.R.; CHEN, R.; CIRALDO, I.; COLONNA, M.; CUTULI, M.; D'AGOSTINO, G.; DELAUNAY, F.; DESHMUKH, N.; DJAPO, H.; GAMBACURTA, D.; DE GERONIMO, G.; DE LOS RÌOS, K.; EKE, C.; FERRARESI, C.; FERREIRA, J.L.; FERRETTI, J.; FINOCCHIARO, P.; FIRAT, S.; FISICHELLA, M.; FLECHAS GARCIA, D.C.; FOTI, A.; GANDOLFO, E.; GARCIA-TECOCOATZI, H.; HACISALIHOGLU, A.; HUERTA-HERNANDEZ, A.; KOTILA, J.; KUCUK, Y.; IAZZI, F.; JIVAN, H.; LANZALONE, G.; LAY, J.A.; LA FAUCI, L.; LA VIA, F.; LENSKE, H.; LINARES, R.; LUBIAN, J.; MA, J.; MARIN-LÁMBARRI, D.; MAS RUIZ, J.; MEDINA, N.H.; MENDES, D.R.; MEREU, P.; MORALLES, M. ; NERI, L.; NEVELING, R.; OLIVEIRA, J.R.B.; PAKOU, A.; PANDOLA, L.; PELLEGRI, L.; PETRASCU, H.; PIETRALLA, N.; PINNA, F.; REITO, S.; RIES, P.C.; RUSSO, A.D.; RUSSO, G.; SANTOPINTO, E.; SANTOS, R.B.B.; SERBINA, L.; SGOUROS, O.; SILVEIRA, M.A.G. da; SOLAKCI, S.O.; SOULIOTIS, G.; SOUKERAS, V.; SPATAFORA, A.; TORRESI, D.; TUDISCO, S.; VARGAS HERNANDEZ, H.; VSEVOLODOVNA, R.I.M.; WANG, J.; WERNER, V.; YANG, Y.; YILDIRIN, A.; ZAGATTO, V.A.B.. Recent results on heavy-ion direct reactions of interest for 0νββ decay at INFN - LNS. Journal of Physics: Conference Series, v. 1610, p. 1-7, 2020. DOI: 10.1088/1742-6596/1610/1/012004

    Abstract: Neutrinoless double beta decay of nuclei, if observed, would have important implications on fundamental physics. In particular it would give access to the effective neutrino mass. In order to extract such information from 0νββ decay half-life measurements, the knowledge of the Nuclear Matrix Elements (NME) is of utmost importance. In this context the NUMEN and the NURE projects aim to extract information on the NME by measuring cross sections of Double Charge Exchange reactions in selected systems which are expected to spontaneously decay via 0νββ. In this work an overview of the experimental challenges that NUMEN is facing in order to perform the experiments with accelerated beams and the research and development activity for the planned upgrade of the INFN-LNS facilities is reported.

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  • IPEN-DOC 27427

    CARBONE, D.; FERREIRA, J.L.; CALABRESE, S.; CAPPUZZELLO, F.; CAVALLARO, M.; HACISALIHOGLU, A.; LENSKE, H.; LUBIAN, J.; MAGAÑA VSEVOLODOVNA, R.I.; SANTOPINTO, E.; AGODI, C.; ACOSTA, L.; BONANNO, D.; BORELLO-LEWIN, T.; BOZTOSUN, I.; BRISCHETTO, G.A.; BURRELLO, S.; CALVO, D.; CHÁVEZ LOMELÍ, E.R.; CIRALDO, I.; COLONNA, M.; DELAUNAY, F.; DESHMUKH, N.; FINOCCHIARO, P.; FISICHELLA, M.; FOTI, A.; GALLO, G.; IAZZI, F.; LA FAUCI, L.; LANZALONE, G.; LINARES, R.; MEDINA, N.H.; MORALLES, M. ; OLIVEIRA, J.R.B.; PAKOU, A.; PANDOLA, L.; PETRASCU, H.; PINNA, F.; REITO, S.; RUSSO, G.; SGOUROS, O.; SOLAKCI, S.O.; SOUKERAS, V.; SOULIOTIS, G.; SPATAFORA, A.; TORRESI, D.; TUDISCO, S.; YILDIRIN, A.; ZAGATTO, V.A.B.. Analysis of two-nucleon transfer reactions in the 20Ne+116Cd system at 306 MeV. Physical Review C, v. 102, n. 4, p. 044606-1 - 044606-14, 2020. DOI: 10.1103/PhysRevC.102.044606

    Abstract: Background: Heavy-ion induced two-nucleon transfer reactions are powerful tools to reveal peculiar aspects of the atomic nucleus, such as pairing correlations, single-particle and collective degrees of freedom, and more. Also, these processes are in competition with the direct meson exchange in the double charge exchange reactions, which have recently attracted great interest due to their possible connection to neutrinoless double-β decay. In this framework, the exploration of two-nucleon transfer reactions in the 20Ne+116Cd collision at energies above the Coulomb barrier is particularly relevant since the 116Cd nucleus is a candidate for the double-β decay. Purpose: We want to analyze selected transitions to low-lying 0+ and 2+ states of the residual nuclei in the 116Cd(20Ne, 22Ne)114Cd two-neutron pickup and 116Cd(20Ne, 18O)118Sn two-proton stripping reactions at 306 MeV incident energy and determine the role of the couplings with inelastic transitions. Methods: We measured the excitation energy spectra and absolute cross sections for the two reactions using the MAGNEX large acceptance magnetic spectrometer to detect the ejectiles. We performed direct coupled reaction channels and sequential distorted wave Born approximation calculations using the double folding São Paulo potential to model the initial and final state interactions. The spectroscopic amplitudes for two- and singleparticle transitions were derived by different nuclear structure approaches: microscopic large-scale shell model, interacting boson model-2 and quasiparticle random phase approximation. Results: The calculations are able to reproduce the experimental cross sections for both two-neutron and twoproton transfer reactions. The role of couplings with the inelastic channels are found to be important in the two-proton transfer case. A competition between the direct and the sequential process is found in the reaction mechanism. For the two-proton transfer case, the inclusion of the 1g7/2 and 2d5/2 orbitals in the model space is crucial. Conclusions: The approach presented here, combination of nuclear structure and reaction mechanism ingredients, is a very promising tool for the analysis of two-neutron and two-proton transfer reactions between heavy nuclei.

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  • IPEN-DOC 27426

    FINOCCHIARO, PAOLO; ACOSTA, LUIS; AGODI, CLEMENTINA; ALTANA, CARMEN; AMADOR-VALENZUELA, PAULINA; BOZTOSUN, ISMAIL; BRASOLIN, SANDRO; BRISCHETTO, GIUSEPPE A.; BRUNASSO, OSCAR; CALABRESE, SALVATORE; CALABRETTA, LUCIANO; CALVO, DANIELA; CAPIROSSI, VITTORIA; CAPPUZZELLO, FRANCESCO; CARBONE, DIANA; CAVALLARO, MANUELA; CHÁVEZ LOMELI, EFRAIN R.; CIRALDO, IRENE; D'AGOSTINO, GRAZIA; DELAUNAY, FRANCK; DJAPO, HARIS; FERRARESI, CARLO; FISICHELLA, MARIA; FLECHAS GARCIA, DAVID C.; IAZZI, FELICE; LA FAUCI, LAURA; LANZALONE, GAETANO; LA VIA, FRANCESCO; LINARES, ROBERTO; MEDINA, NILBERTO H.; MEREU, PAOLO; MORALLES, MAURICIO ; OLIVEIRA, JOSÉ R.B.; PANDOLA, LUCIANO; PAPPALARDO, ALFIO; PETRASCU, HORIA; PINNA, FEDERICO; RUSSO, ANTONIO D.; SARTIRANA, DIEGO; SGOUROS, ONOUFRIOS; SOLAKCI, SELÇUK O.; SOUKERAS, VASILIS; SPATAFORA, ALESSANDRO; TORRESI, DOMENICO; TUDISCO, SALVATORE; YILDIRIN, AYDIN; ZAGATTO, VINICIUS A.B... The NUMEN heavy ion multidetector for a complementary approach to the Neutrinoless Double Beta Decay. Universe, v. 6, n. 9, p. 1-31, 2020. DOI: 10.3390/universe6090129

    Abstract: Neutrinos are so far the most elusive known particles, and in the last decades many sophisticated experiments have been set up in order to clarify several questions about their intrinsic nature, in particular their masses, mass hierarchy, intrinsic nature of Majorana or Dirac particles. Evidence of the Neutrinoless Double-Beta Decay (NDBD) would prove that neutrinos are Majorana particles, thus improving the understanding of the universe itself. Besides the search for several large underground experiments for the direct experimental detection of NDBD, the NUMEN experiment proposes the investigation of a nuclear mechanism strongly linked to this decay: the Double Charge Exchange reactions (DCE). As such reactions share with the NDBD the same initial and final nuclear states, they could shed light on the determination of the Nuclear Matrix Elements (NMEs), which play a relevant role in the decay. The physics of DCE is described elsewhere in this issue, while the focus of this paper will be on the challenging experimental apparatus currently under construction in order to fulfil the requirements of the NUMEN experiment. The overall structure of the technological improvement to the cyclotron, along with the newly developed detection systems required for tracking and identifying the reaction products and their final excitation level are described.

    Palavras-Chave: neutrinos; double beta decay; desulfurization; magnetic spectrometers; nuclear matrix; charge exchange; heavy ions; ion detection; cyclotrons

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  • IPEN-DOC 27425

    NANDENHA, J. ; YAMASHITA, J.Y. ; SOUZA, F.M.; FONTES, E.H. ; BATISTA, B.L.; SANTOS, M.C.; LINARDI, M. ; NETO, A.O. . Methane activation on PdMn/C‑ITO electrocatalysts using a reactor‑type PEMFC. Research on Chemical Intermediates, v. 46, n. 10, p. 4383-4402, 2020. DOI: 10.1007/s11164-020-04210-y

    Abstract: Various palladium and manganese supported in a mix of carbon and indium thin oxide (PdMn/C-ITO) compositions were synthesized by a sodium borohydride reduction process for methane activation at low temperatures in a proton exchange membrane fuel cell (PEMFC) reactor. These electrocatalysts were characterized by X-ray diffraction, transmission electron microscopy (TEM), X-ray photoelectron spectroscopy XPS, inductively coupled plasma mass spectrometry ICP-MS, attenuated total reflection-Fourier transform infrared spectroscopy, cyclic voltammetry and a PEMFC reactor. The diffractograms of PdMn/C-ITO electrocatalysts revealed the face-centered cubic structure of palladium and the bixbyite cubic structure of In2O3. TEM experiments showed mean nanoparticle sizes between 4.7 and 5.2 nm for all electrocatalysts. XPS results showed the presence of palladium and manganese oxides, as well as Pd0 species. Cyclic voltammograms of PdMn/C-ITO electrocatalysts showed an increase in current density values after the methane adsorption, this result is related to formation of methanol or formic acidic. Polarization curves at 80 °C acquired in a PEMFC reactor showed that PdMn(70:30)/C-ITO and PdMn(50:50)/C-ITO have superior performance when compared to Pd/C-ITO indicating the beneficial effect of adding Mn, this behavior can be attributed to the bifunctional mechanism or to the electronic effect of support.

    Palavras-Chave: methane; oxidation; borohydrides; reduction; sodium compounds; proton exchange membrane fuel cells; transmission electron microscopy; electrocatalysts; electrolytes

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  • IPEN-DOC 27424

    XIAO, DA; WANG, NANCHAO; SHEN, XUE; LANDULFO, EDUARDO ; ZHONG, TIANFEN; LIU, DONG. Development of ZJU high-spectral-resolution lidar for aerosol and cloud: extinction retrieval. Remote Sensing, v. 12, n. 18, p. 1-18, 2020. DOI: 10.3390/rs12183047

    Abstract: The retrieval of the extinction coefficients of aerosols and clouds without assumptions is the most important advantage of the high-spectral-resolution lidar (HSRL). The standard method to retrieve the extinction coefficient from HSRL signals depends heavily on the signal-to-noise ratio (SNR). In this work, an iterative image reconstruction (IIR) method is proposed for the retrieval of the aerosol extinction coefficient based on HSRL data, this proposed method manages to minimize the difference between the reconstructed and raw signals based on reasonable estimates of the lidar ratio. To avoid the ill-posed solution, a regularization method is adopted to reconstruct the lidar signals in the IIR method. The results from Monte-Carlo (MC) simulations applying both standard and IIR methods are compared and these comparisons demonstrate that the extinction coefficient and the lidar ratio retrieved by the IIR method have smaller root mean square error (RMSE) and relative bias values than the standard method. A case study of measurements made by Zhejiang University (ZJU) HSRL is presented, and their results show that the IIR method not only obtains a finer structure of the aerosol layer under the condition of low SNR, but it is also able to retrieve more reasonable values of the lidar ratio.

    Palavras-Chave: optical radar; aerosols; monte carlo method; signal-to-noise ratio; iterative methods; image processing; climatic change; scattering

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  • IPEN-DOC 27423

    CUEVAS-ARIZACA, E.E.; MAXIMO RONDON, R.; ROCCA, R.R.; GOMES, M.B. ; CORTEZ, B. ; GONZALES-LORENZO, C.D.; TAKARA, J.H.; GUNDU RAO, T.; CANO, N.F.; CHUBACI, J.F.D.; CAMPOS, L.L. ; WATANABE, S.. Study of thermoluminescence of green quartz pellets for low dose dosimetry. Radiation Physics and Chemistry, v. 177, p. 1-5, 2020. DOI: 10.1016/j.radphyschem.2020.109142

    Abstract: Green quartz is usually studied for low dose TL dosimetry of gamma and X radiation. The aim of the present work is the dosimetric characterization of natural green quartz in the dose range of 0.47 mGy up to 1000 mGy of gamma and X radiation. Green quartz pellets were produced by cold pressing green quartz powder. The pellets are very sensitive to gamma and X radiation with main prominent TL peak at 230 °C. The TL sensitivity of MTS-N (LiF:Mg,Ti) and green quartz pellets were also compared. The dose response curve presented linear behavior in the dose range studied. The glow curve was deconvoluted. Kinetic parameters such as trap depth, kinetic order (b) and frequency factor (s) are determined. The TL photon energy dependence was also evaluated.

    Palavras-Chave: quartz; thermoluminescence; thermoluminescent dosimetry; energy dependence; gamma radiation; x radiation; photons; photon temperature

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  • IPEN-DOC 27422

    SANTOS, WILLIAM S.; SOUZA, LUCAS W.G.; NEVES, LUCIO P.; PERINI, ANA P.; SANTOS, CARLA J.; BELINATO, WALMIR; CALDAS, LINDA V.E. . Evaluation of fetal, medical and occupational exposure in ERCP procedures using Monte Carlo simulation and virtual anthropomorphic phantoms. Radiation Physics and Chemistry, v. 177, p. 1-10, 2020. DOI: 10.1016/j.radphyschem.2020.109113

    Abstract: In this study, computational modeling was applied to evaluate medical and occupational exposure, to ionizing radiation, during the Endoscopic Retrograde Cholangiopancreatography (ERCP) procedure of a pregnant woman in the second gestational trimester. The fetal dose evaluation and the construction of a photon fluence map inside the procedure room were also performed. The medical staff and patient were represented by virtual anthropomorphic phantoms. These phantoms were incorporated to the radiation transport code MCNPX (version 2.7.0). The photon beam was projected on the right lateral lower section of the liver of the patient, producing a FOV of 15×15 cm2. The spectral influence was evaluated using tube voltages of 70 kVp and 80 kVp with a total filtration of 5 mmAl. The influence of the suspended shield, lead curtain and fetal shield were evaluated on the Conversion Coefficients for Equivalent Dose (CC[HT]) and Effective Dose (CC[E]) for the medical staff and patient. The removal of the lead curtain and suspended shield was considered the most critical configuration to the medical staff. In this situation, an increase up to 633% in the CC[HT]eye lens and 900% in CC[E], for the medical staff, was reached. The CC[E]Patient ranged between 0.13 mSv/Gy.cm2 (70 kVp with all protective devices) and 0.15 mSv/Gy.cm2 (80 kVp without fetal shield) and the values obtained are in agreement with the literature. The CC[HT]fetus oscillated between 2.2E-1 mSv/Gy.cm2 (70 kV with fetal shield) and 2.7E-1 mSv/Gy.cm2 (80 kV without fetal shield). The outcomes of this work are useful in the prior monitoring of the radiation doses and risks, and a reduction on these may be reached for the medical team and patient, which is a complicated arrangement in ERCP procedures.

    Palavras-Chave: biomedical radiography; digestive system; pregnancy; prenatal exposure; patients; monte carlo method; phantoms; medical personnel; nuclear medicine; conversion; computerized simulation; mathematical models; radiation doses; fetuses

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  • IPEN-DOC 27421

    MARANI, LUCIANO; GATTI, LUCIANA V. ; MILLER, JOHN B.; DOMINGUES, LUCAS G. ; CORREIA, CAIO C.S. ; GLOOR, MANUEL; PETERS, WOUTER; BASSO, LUANA S.; CRISPIM, STEPHANE P.; NEVES, RAIANE A.L.. Métodos de estimativas de fluxo de gases de efeito estufa e a influência da ação humana na redução da capacidade de remoção de CO2 na Floresta Amazônica / Estimation methods of greenhouse gases fluxes and the human influence in the CO2 removal capability of the Amazon Forest. Revista Virtual de Química, v. 12, n. 5, p. 1129-1144, 2020. DOI: 10.21577/1984-6835.20200091

    Abstract: A Floresta Amazônica desempenha um papel importante para o clima tropical da América do Sul, em particular para a recirculação do vapor d’água para a atmosfera e representa um potencial reservatório de carbono que se fosse liberado totalmente contribuiria significativamente com o aquecimento global. Toda a região está sob forte pressão humana, através de exploração madeireira, conversão de floresta e outras formas de exploração de recursos. Este trabalho apresenta uma forma de examinar os fluxos de carbono na Amazônia, ao realizar perfis verticais atmosféricos de CO2 com aeronaves de pequeno porte regularmente e que sejam representativos de escalas regionais. Ao combinar estas medidas com os registros de background nas ilhas de Barbados e de Ascenção, o fluxo médio mensal de carbono para cerca de 20 % da Amazônia Brasileira pode ser estimado. Existem dois desafios primários nas medidas de CO2: precisão e acurácia. O método desenvolvido para garantir tanto a precisão quanto a acurácia dessas medidas também é apresentado. A análise das linhas de tendência entre as medidas no topo de perfil e das medidas realizadas abaixo da Camada Limite Planetária mostra uma mudança de contribuição ao longo do período estudado, que é confirmada quando se analisam os fluxos médios anuais de CO2. A tendência de mudança nos fluxos mostra comportamentos similares aos observados na mudança do uso da terra, principalmente na conversão de áreas de floresta em áreas de agropecuária, destacando a influência da ação humana na mudança da Amazônia Oriental de um sumidouro para um emissor de CO2 atmosférico.

    Palavras-Chave: climatic change; greenhouse gases; carbon dioxide; greenhouse effect; environment; environmental impacts; ambient temperature; earth atmosphere; amazon river

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  • 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.

    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.

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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.

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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%.

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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.

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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.

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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.

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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.

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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.

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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.

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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.

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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.

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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.

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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.

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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.

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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).

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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.

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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.

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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.

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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.

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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.

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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.

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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.

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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.

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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.

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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.

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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.

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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.

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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.

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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.

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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.

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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.

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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.

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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.

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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.

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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.

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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.

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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.

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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.

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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.

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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.

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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.

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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.

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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.

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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.

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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.

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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.

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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.

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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.

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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.

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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.

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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.

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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.

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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 .

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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.

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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.

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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 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 27303

    CAETANO, GABRIELA A.; LUZ, TEMISTOCLES de S.; COELHO, LUCAS M.; ROSSI, JESUALDO L. ; ORLANDO, MARCOS T.D.. Efeito de tratamentos térmicos nas propriedades mecânicas de chapas soldadas do aço inoxidável duplex UNS S32304 / Effect of heat treatments on the mechanical properties in UNS S32304 duplex stainless steel welded plates. Tecnologia em Metalurgia, Materiais e Mineração, v. 16, Especial, 2019. DOI: 10.4322/2176-1523.20191931

    Abstract: O aço inoxidável duplex UNS S32304 tem sido investigado como candidato para construção de um receptáculo para transporte de material radioativo associado ao futuro Reator Multipropósito Brasileiro (RMB). O foco deste trabalho é avaliar o efeito de diferentes temperaturas de tratamento térmico em chapas de UNS S32304 com espessura de 1,8mm após processo de soldagem TIG autógeno. Utilizou-se corrente pulsada com polaridade direta, gás de proteção com uma mistura de argônio e 2% de nitrogênio e um sistema de acionamento automático com controle digital dos parâmetros. Os corpos de prova soldados e como recebido foram tratados termicamente durante 8h a temperaturas de 475, 600 e 750°C seguido de resfriamento ao ar. As amostras foram submetidas a ensaios de tração com taxa de deformação de 10-4s-1. Comprovou-se que somente a amostra tratada a 600°C mostrou um comportamento tensão-deformação similar à amostra como recebida. Para as amostras soldadas, o tratamento a 600°C aumentou o limite de resistência à tração e o alongamento % total em relação à amostra somente soldada e sem tratamento térmico.

    Palavras-Chave: heat treatments; stainless steels; gas tungsten-arc welding; strains; stresses; chemical composition; corrosion resistance; welding; plates

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  • IPEN-DOC 26680

    ESTRADA-VILLEGAS, G.M.; MORSELLI, G. ; OLIVEIRA, M.J.A. ; GONZALEZ-PEREZ, G. ; LUGAO, A.B. . PVGA/Alginate-AgNPs hydrogel as absorbent biomaterial and its soil biodegradation behavior. Polymer Bulletin, v. 77, n. 8, p. 4147-4166, 2020. DOI: 10.1007/s00289-019-02966-x

    Abstract: PVGA, silver nitrate ( AgNO3) and alginate (Alg) were cross-linked by using γ-ray radiation to obtain Alg/PVGA/AgNPs as a potential biomaterial. The hydrogel composition was characterized by several analytics methods, and the morphology was evaluated by scanning electron microscopy. The swelling behavior was tested in different mediums. The stability of AgNPs was followed by UV–Vis at 400 nm for 1 month. The hydrogel soil biodegradation was analyzed by visual observation, weight loss, Fourier transform infrared spectroscopy and thermogravimetric analysis for 120 days. A simple biodegradation mechanism has been proposed based on results. Additionally, cytotoxicity assays were carried out using NCTC 929 cells to observe cell viability.

    Palavras-Chave: hydrogels; silver; biological materials; biodegradation; cross-linking; nanoparticles; toxicity; bioassay; fourier transform spectrometers; spectroscopy

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  • IPEN-DOC 26565

    NOGUEIRA, ANDRE L.; MUNITA, CASIMIRO S. . Quantitative methods of standardization in cluster analysis: finding groups in data. Journal of Radioanalytical and Nuclear Chemistry, v. 325, n. 3, p. 719-724, 2020. DOI: 10.1007/s10967-020-07186-6

    Abstract: The aim of this paper is to evaluate the impact of three standardization methods (z-score, log10 and improved min–max) in determining the number of clusters for a dataset of 146 archaeological ceramic fragments in which mass fractions of chemical elements were determined by INAA. The results showed a tendency towards clustering, which did not occur to the non-standardized data. The standardization methods indicated the presence of three groups within the database. Quality evaluation of these clusters, by means of internal validation indexes, showed that the best performance was obtained with the log10 transformation. This transformation also performed well in the calculation of compactness, while the improved min–max showed better performance in terms of separability.

    Palavras-Chave: archaeological sites; cesium; europium; thorium; isotope dating; neutron activation analysis; quantitative chemical analysis; standardization

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  • IPEN-DOC 27255

    LO PRESTI, DOMENICO; MEDINA, NILBERTO H.; GUAZZELLI, MARCILEI A.; MORALLES, MAURICIO ; AGUIAR, VITOR A.P.; OLIVEIRA, JOSE R.B.; ADDED, NEMITALA; MACCHIONE, EDUARDO L.A.; SIQUEIRA, PAULO de T.D. ; ZAHN, GUILHERME ; GENEZINI, FREDERICO ; BONANNO, DANILO; GALLO, GIUSEPPE; RUSSO, SALVATORE; SGOUROS, ONOUFRIOS; MUOIO, ANNAMARIA; PANDOLA, LUCIANO; CAPPUZZELLO, FRANCESCO. Neutron radiation effects on an electronic system on module. Review of Scientific Instruments, v. 91, n. 8, p. 083301-1 - 083301-5, 2020. DOI: 10.1063/5.0010968

    Abstract: The NUMEN (NUclear Matrix Elements for Neutrinoless double beta decay) project was recently proposed with the aim to investigate the nuclear response to Double Charge Exchange reactions for all the isotopes explored by present and future studies of 0νββ decay. The expected level of radiation in the NUMEN experiment imposes severe limitations on the average lifetime of the electronic devices. During the experiments, it is expected that the electronic devices will be exposed to about 105 neutrons/cm2/s according to FLUKA simulations. This paper investigates the reliability of a System On Module (SOM) under neutron radiation. The tests were performed using thermal, epithermal, and fast neutrons produced by the Instituto de Pesquisas Energéticas e Nucleares 4.5MWNuclear Research Reactor. The results show that the National Instruments SOM is robust to neutron radiation for the proposed applications in the NUMEN project.

    Palavras-Chave: nuclear matrix; neutrons; modulation; silver nitrates; calculation methods; neutron beams; charge exchange

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  • IPEN-DOC 27254

    SARKAR, CHINMOY; GUENTHER, ALEX B.; PARK, JEONG-HOO; SECO, ROGER; ALVES, ELIANE; BATALHA, SARAH; SANTANA, RAONI; KIM, SAEWUNG; SMITH, JAMES; TOTA, JULIO; VEGA, OSCAR . PTR-TOF-MS eddy covariance measurements of isoprene and monoterpene fluxes from an eastern Amazonian rainforest. Atmospheric Chemistry and Physics, v. 20, n. 12, p. 7179-7191, 2020. DOI: 10.5194/acp-20-7179-2020

    Abstract: Biogenic volatile organic compounds (BVOCs) are important components of the atmosphere due to their contribution to atmospheric chemistry and biogeochemical cycles. Tropical forests are the largest source of the dominant BVOC emissions (e.g. isoprene and monoterpenes). In this study, we report isoprene and total monoterpene flux measurements with a proton transfer reaction time-of-flight mass spectrometer (PTR-TOF-MS) using the eddy covariance (EC) method at the Tapajós National Forest (2.857∘ S, 54.959∘ W), a primary rainforest in eastern Amazonia. Measurements were carried out from 1 to 16 June 2014, during the wet-to-dry transition season. During the measurement period, the measured daytime (06:00–18:00 LT) average isoprene mixing ratios and fluxes were 1.15±0.60 ppb and 0.55±0.71 mg C m−2 h−1, respectively, whereas the measured daytime average total monoterpene mixing ratios and fluxes were 0.14±0.10 ppb and 0.20±0.25 mg C m−2 h−1, respectively. Midday (10:00–14:00 LT) average isoprene and total monoterpene mixing ratios were 1.70±0.49 and 0.24±0.05 ppb, respectively, whereas midday average isoprene and monoterpene fluxes were 1.24±0.68 and 0.46±0.22 mg C m−2 h−1, respectively. Isoprene and total monoterpene emissions in Tapajós were correlated with ambient temperature and solar radiation. Significant correlation with sensible heat flux, SHF (r2=0.77), was also observed. Measured isoprene and monoterpene fluxes were strongly correlated with each other (r2=0.93). The MEGAN2.1 (Model of Emissions of Gases and Aerosols from Nature version 2.1) model could simulate most of the observed diurnal variations (r2=0.7 to 0.8) but declined a little later in the evening for both isoprene and total monoterpene fluxes. The results also demonstrate the importance of site-specific vegetation emission factors (EFs) for accurately simulating BVOC fluxes in regional and global BVOC emission models.

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  • IPEN-DOC 27253

    LANDULFO, EDUARDO ; VEGA, ALBEHT R.; YOSHIDA, ALEXANDRE C. ; BASTIDAS, ALVARO; SANTOS, AMANDA V. dos; SILVA, ANTONIETA; GOMES, ANTONIO A. ; GONZALEZ, BORIS B.; MELO-LUNA, CARLOS A.; HOYOS, CARLOS D.; RAE, CRISTINA T. de S.; CAMILO, DANIEL; VIVAS, DAVID; GOUVEIA, DIEGO A.; WOLFRAM, ELIAN; COLLINI, ESTELA; LOPES, FABIO J.S. ; MOREIRA, GREGORI de A. ; BARBOSA, HENRIQUE de M.J.; CIMINARI, HERNAN; REINA, JOHN H.; SILVA, JONATAN J. da ; CESPEDES, JONNATHAN; MARRERO, JUAN C.A.; RASCADO, JUAN L.G.; PALLOTTA, JUAN; HOELZEMANN, JUDITH; ARBOLEDAS, LUCAS A.; SALLES, M.ALEJANDRA; SILVA, MARCOS P.A. da; SAMMARA, RENATA; FORNO, RICARDO N.; PAPANDREA, SEBASTIAN. LALINET network status. EPJ Web Conferences, v. 237, p. 1-4, 2020. DOI: 10.1051/epjconf/202023705008

    Abstract: LALINET (Latin American Lidar Network) follows its goal to consolidation as a federative lidar network to provide regional coverage over Latin America in providing aerosol and greenhouse gas profiles following QA/QC protocols and promoting the development of researchers and students in atmopheric science field. We show recent results on different approaches for studying the optical properties of the atmosphere regarding aerosols at tropospheric and stratospheric level and greenhouse gas mixing ratio profiles followed by our recent support and validation efforts towards present and future satellite missions.

    Palavras-Chave: computer networks; optical radar; inventories; monitoring; optical properties; distribution

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  • IPEN-DOC 27252

    ROVANI, SUZIMARA ; SANTOS, JONNATAN J.; GUILHEN, SABINE N. ; CORIO, PAOLA; FUNGARO, DENISE A. . Fast, efficient and clean adsorption of bisphenol-A using renewable mesoporous silica nanoparticles from sugarcane waste ash. RSC Advances, v. 10, n. 46, p. 27706–27712, 2020. DOI: 10.1039/d0ra05198e

    Abstract: Even with all the biological problems associated with bisphenol-A (BPA), this chemical is still being widely used, especially in thermal paper receipts. In this study, renewable mesoporous silica nanoparticles (MSN), obtained from sugarcane ash, functionalized with hexadecyltrimethylammonium (CTAB) were applied as an adsorbent in the removal of BPA from the aqueous solution. The versatility of this material and its BPA adsorption capacity were tested at different pH values, being practically constant at pH between 4 and 9, with a slight increase in pH 10 and a greater increase in pH 11. The removal time evaluation indicates a very fast adsorption process, removing almost 90% of BPA in the first 20 min of contact. The kinetic model indicates a monolayer formation of BPA molecules on the MSN-CTAB surface. The maximum adsorption capacity (Qmax) was 155.78 mg g-1, one of the highest found in literature, and the highest for material from a renewable source.

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  • IPEN-DOC 27251

    SILVA, JONATAN da ; MORAIS, FERNANDO G. ; FRANCO, MARCO A.; LOPES, FABIO J.S. ; ARRUDA, GREGORI de A. ; YOSHIDA, ALEXANDRE C. ; CORREIA, ALEXANDRE; LANDULFO, EDUARDO . Exploring the twilight zone: a multi-sensor approach. EPJ Web Conferences, v. 237, p. 1-4, 2020. DOI: 10.1051/epjconf/202023707015

    Abstract: This study shows a set of analysis of measurements from ground-based and satellite instruments to characterize the twilight zone (TLZ) between clouds and aerosols in São Paulo, Brazil. In the vicinity of clouds turbulence measurements showed an intense upward movement of aerosol layers, while sunphotometer results showed an increase in aerosol optical depth, and lidar measurements showed an increase in the backscatter vertical profile signal.

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  • IPEN-DOC 27250

    MEDEIROS, VINICIUS L.; ARAUJO, LEANDRO G. de ; RATERO, DAVI R.; PAULA, ALEX S.; MOLINA, EDUARDO F.; JAEGER, CHRISTIAN; MARUMO, JULIO T. ; NERY, JOSE G.. Synthesis and physicochemical characterization of a novel adsorbent based on yttrium silicate: a potential material for removal of lead and cadmium from aqueous media. Journal of Environmental Chemical Engineering, v. 8, n. 4, p. 1-10, 2020. DOI: 10.1016/j.jece.2020.103922

    Abstract: A new metallosilicate based on yttrium was synthesized and characterized by XRD, FT-IR, 29Si MAS-NMR, and 89Y MAS-NMR. The mixed framework of the material was confirmed by the detection of distinct chemical shift groups using 29Si MAS-NMR (at -82 to -87 ppm, -91 to -94 ppm, -96 to -102 ppm, and -105 to -108 ppm), as well as four distinct chemical shifts in the 89Y MAS-NMR spectrum (at -89, -142, -160, and -220 ppm). Adsorption and kinetic analyses indicated the potential of the new material for the removal of lead and cadmium from aqueous media. The adsorption results for lead indicated that dynamic equilibrium was reached after five hours, with total lead removal of around 94 %, while for cadmium it was reached in the first hour, with total cadmium removal of around 74 %. The adsorptions of lead and cadmium were modeled using pseudo-first order (PFO) and pseudo-second order (PSO) kinetic models. Although both models provided high R2 values (0.9903 and 0.9980, respectively), the PSO model presented a much lower χ2 red value (4.41×10−4), compared to the PFO model (2.12×10−3), which indicated that the rate-limiting step was probably due to the chemisorption of lead from the solution onto the yttrium-based metallosilicate.

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  • IPEN-DOC 27249

    SILVA, E. ; SANTOS, L.R.; ASSEMANY, L.P.F. ; POTIENS, M.P.A. . Evaluation of the performance of radioprotection ionization chambers used in radiometric survey of clinical systems. Brazilian Journal of Radiation Sciences, v. 8, n. 1A, p. 1-10, 2020. DOI: 10.15392/bjrs.v8i1A.1076

    Abstract: The use of ionizing radiation for medical purposes was a major advancement for society due to the various possibilities of use for the treatment and diagnosis of diseases. On the other hand, knowledge about the damage caused by the biological effects of ionizing radiation requires a continuous improvement of the quality control of diagnostic radiology. Radiation detector equipment is used to measure the levels of radiation emitted by sources be they natural or artificial. For practicality and precision, among the most commonly used detectors are the ionization chambers. Especially in outdoor areas climatic factors may affect the behavior of these detectors at the time of measurement, but Brazilian legislation only recommends the calibration of these measuring instruments in a traceable laboratory every two years to ensure their reliability. The objective of this work was to evaluate the performance of an ionization chamber used in radioprotection measurements in diagnostic radiology equipment, considering the climatic variations in the different regions of Brazil. For this, a system was developed to simulate the environmental conditions found for the parameters of temperature and humidity at the time of clinical measurements, making it possible to estimate the influence of these factors on the values obtained.

    Palavras-Chave: climates; diagnostic techniques; dosimetry; humidity; ionization chambers; performance; radiation protection; radiometric surveys; simulation; strontium 90; yttrium 90; brazil

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  • IPEN-DOC 27248

    LIMA, B.L.; ALMEIDA, J.S. ; POTIENS, M.P.A. ; PELISSONI, R.A.; SAPIENZA, M.T.; BUCHPIGUEL, C.A.; WILLEGAIGNON, J.. Evaluation of biokinetics and dosimetry in [131I]-NaI therapies: quantification of whole body images versus thigh region. Brazilian Journal of Radiation Sciences, v. 8, n. 1A, p. 1-13, 2020. DOI: 10.15392/bjrs.v8i1A.1082

    Abstract: This study evaluate the possibility of restricting the current image quantification (ROI) from the whole body to a small area in thigh for therapy planning. Whole body planar images were obtained from 13 patients after the administration of 131I tracer dose, and OLINDA/EXM software was used for internal dose calculation. The average value of half-life time was 16.46 ± 3.45 h in whole body quantification, compared to 14.07 ± 2.89 h in thigh. The average absorbed dose in bone marrow from the whole body quantification was 0.0519 ± 0.0250 mGy/MBq, whilst the absorbed dose provided by the thigh quantification represented 87% of this value, with up to 95% in time reduction for dose calculation. Such doses become similar when a correction factor of 1.13 is applied in thigh dose results (p=0.67), which is within the variation coefficient assumed to internal dosimetry (20%). This study shows the possibility of a significant time reduction in internal dose calculation applied to therapy planning.

    Palavras-Chave: absorbed radiation doses; bone marrow; dosimetry; iodine 131; limbs; neoplasms; patients; planning; radionuclide kinetics; single photon emission computed tomography; thyroid; whole-body irradiation

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  • IPEN-DOC 27247

    VARCA, JUSTINE P.R.O. ; MARTINS, ELAINE A.J. ; VARCA, GUSTAVO H.C. ; ROMANO, RENATO L.; LEBRE, DANIEL T.; LAINETTI, PAULO E.O. ; BUSTILLOS, JOSE O.V. . Determination of organochlorines in soil of a suburban area of São Paulo Brazil. International Journal of Environmental Research and Public Health, v. 17, n. 16, p. 1-16, 2020. DOI: 10.3390/ijerph17165666

    Abstract: Technological advances have promoted improvements in several science fields, especially related to environmental and analytical areas with the improvement of detection and development of environmentally friendly extraction techniques. This study applied Quick, Easy, Cheap, Effective, Rugged and Safe method (QuEChERS) for soil extraction and assessed its performance through a validation study using samples from the soil of a contaminated area in Caieiras, SP, Brazil. Nine organochlorine pesticides, including the isomers alpha, beta, gamma and delta- hexachlorocyclohexane; cis- and trans-heptachlor epoxide; cis- and trans-chlordane and heptachlor were analyzed by gas chromatography coupled to electron capture detector. The method was validated according to ISO 5725-4 (2020), EURACHEM (2014) and DOQ-CGCRE-008 (2016). The limits of detection and quantification of the method for the nine organochlorines were α-HCH (1.2 and 12.6 µg kg−1), β-HCH (1.7 and 12.0 µg kg−1), γ-HCH (1.5 and 11.6 µg kg−1), δ-HCH (0.8 and 11.6 µg kg−1), heptachlor (1.0 and 10.8 µg kg−1), cis-heptachlor epoxide (0.9 and 11.5 µg kg−1), trans-heptachlor epoxide (0.9 and 11.5 µg kg−1), cis-chlordane (0.4 and 7.9 µg kg−1) and trans-chlordane (0.5 and 10.9 µg kg−1), respectively, and all of them were within the maximum limits recommended by the EPA for the compounds α-HCH (86.0 and 360.0 µg kg−1), β-HCH (300.0 and 1.3 × 103 µg kg−1), γ-HCH (570.0 and 2.5 × 103 µg kg−1), δ-HCH (not defined), heptachlor (130.0 and 630.0 µg kg−1), cis-/trans-heptachlor epoxide (7.0 and 330.0 µg kg−1), cis-/trans-chlordane (1.77 × 103 and 7.7 × 103 µg kg−1) in residential and industrial soil, respectively. Recovery results were between 65% and 105% for almost all compounds, which is an optimum result for multi-residue analytical methods, considering the complexity of the matrix used in the study. Caieiras presented contamination levels of α-HCH in the range of 2.0 to 66.0 µg g−1, which was higher than the limits established by EPA, corresponding to 0.077 µg g−1 for residential soil and 0.27 µg g−1 for industrial soil. According to the validation study, the analytical method proposed was reliable for organochlorine quantification, and the QuEChERS was considered efficient for organochlorine extraction from soil.

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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.