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

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

 

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  • IPEN-DOC 26449

    ARAUJO-SILVA, R.A. de; JORGE JUNIOR, A.M.; VEGA, L.E.R.; LEAL NETO, R.M. ; LEIVA, D.R.; BOTTA, W.J.. Hydrogen desorption/absorption properties of the extensively cold rolled β Ti-40Nb alloy. International Journal of Hydrogen Energy, v. 44, n. 36, p. 20133-20144, 2019. DOI: 10.1016/j.ijhydene.2019.05.211

    Abstract: β Ti-Nb BCC alloys are potential materials for hydrogen storage in the solid state. Since these alloys present exceptional formability, they can be processed by extensive cold rolling (ECR), which can improve hydrogen sorption properties. This work investigated the effects of ECR accomplished under an inert atmosphere on H2 sorption properties of the arc melted and rapidly solidified β Ti40Nb alloy. Samples were crushed in a rolling mill producing slightly deformed pieces within the millimeter range size, which were processed by ECR with 40 or 80 passes. Part of undeformed fragments was used for comparison purposes. All samples were characterized by scanning electron microscopy, x-ray diffractometry, energy-dispersive spectroscopy, hydrogen volumetry, and differential scanning calorimetry. After ECR, samples deformed with 40 passes were formed by thick sheets, while several thin layers composed the specimens after 80 passages. Furthermore, deformation of β Ti-40Nb alloys synthesized samples containing a high density of crystalline defects, cracks, and stored strain energy that increased with the deformation amount and proportionally helped to overcome the diffusion's control mechanisms, thus improving kinetic behaviors at low temperature. Such an improvement was also correlated to the synergetic effect of resulting features after deformation and thickness of stacked layers in the different deformation conditions. At the room temperature, samples deformed with 80 passes absorbed ~2.0 wt% of H2 after 15 min, while samples deformed with 40 passes absorbed ~1.8 wt% during 2 h, excellent results if compared with undeformed samples hydrogenated at 300 C that acquired a capacity of ~1.7 wt% after 2 h. The hydrogen desorption evolved in the same way as for absorption regarding the deformation amount, which also influenced desorption temperatures that were reduced from ~270 C, observed for the undeformed and samples deformed with 40 passes, to ~220 C, for specimens rolled with 80 passes. No significant loss in hydrogen capacity was observed in the cold rolled samples.

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  • IPEN-DOC 26447

    SILVA, ANDERSON F.V. da; FAGUNDES, ANA P.; MACUVELE, DOMINGOS L.P.; CARVALHO, ELITA F.U. de ; DURAZZO, MICHELANGELO ; PADOIN, NATAN; SOARES, CINTIA; RIELLA, HUMBERTO G.. Green synthesis of zirconia nanoparticles based on Euclea natalensis plant extract: optimization of reaction conditions and evaluation of adsorptive properties. Colloids and Surfaces A, v. 583, p. 1-10, 2019. DOI: 10.1016/j.colsurfa.2019.123915

    Abstract: The development of nanomaterials has attracted increasing attention recently. The study of new technologies to obtain these materials becomes extremely important since the majority of the nanomaterials synthesized require reagents and solvents. These reagents and solvents are sometimes toxic and may generate harmful residues to the environment and the health of living beings. Therefore, green synthesis is a potential alternative to obtain nanoparticles, sustainably, using ecological sources. This study developed a method of synthesizing the green of zirconia (ZrO2) nanoparticles using Euclea natalensis (Natal gwarri or Natal ebony tree with African origin) plant extract. Moreover, the adsorptive properties against tetracycline were evaluated. A factorial design was applied in the synthesis process, and an optimization of the reaction parameters (plant extract concentration, precursor concentration, and calcination temperature) was also described for the first time in literature. The nanoparticles were characterized using the XRD, FTIR and TEM techniques, and then subjected to batch adsorption tests. The samples presented the zirconia monoclinic and tetragonal phases, according to the XRD analysis, yielding materials with minimum crystallite sizes equal to 5.25 nm. The FTIR spectra confirmed the results obtained by the XRD, presenting band characteristic of the zirconia monoclinic and tetragonal phases. The particles had a rounded morphology with a very low average diameter ranging from 5.90 to 8.54 nm. Moreover, the nanoparticles were applied to the adsorption of tetracycline. The samples were synthesized with vegetal extract and precursor concentration equal to 50 g L−1 and 0.03 mol L−1, respectively, and calcination temperature of 550 °C, presented in the best performance (loading of 30.45 mg g−1). The adsorption capacity of the zirconia synthesized in this study was significantly higher than other common materials applied to tetracycline removal. The green synthesis procedure, as well as the application of the zirconia nanoparticles to the adsorption of an emerging pollutant, were promising.

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  • IPEN-DOC 26446

    AMARAL, MARCELLO M. ; ZEZELL, DENISE M. ; MONTE, ADAMO F.G.; CARA, ANA C.B. de ; ARAUJO, JEANN C.R.; ANTUNES, ANDREA; FREITAS, ANDERSON Z. . General model for depth-resolved estimation of the optical attenuation coefficients in optical coherence tomography. Journal of Biophotonics, v. 12, n. 10, p. 1-13, 2019. DOI: 10.1002/jbio.201800402

    Abstract: We present the proof of concept of a general model that uses the tissue sample transmittance as input to estimate the depth-resolved attenuation coefficient of tissue samples using optical coherence tomography (OCT). This method allows us to obtain an image of tissue optical properties instead of intensity contrast, guiding diagnosis and tissues differentiation, extending its application from thick to thin samples. The performance of our method was simulated and tested with the assistance of a home built single-layered and multilayered phantoms (~100 μm each layer) with known attenuation coefficient on the range of 0.9 to 2.32 mm−1. It is shown that the estimated depth-resolved attenuation coefficient recovers the reference values, measured by using an integrating sphere followed by the inverse adding doubling processing technique. That was corroborated for all situations when the correct transmittance value is used with an average difference of 7%. Finally, we applied the proposed method to estimate the depth-resolved attenuation coefficient for a thin biological sample, demonstrating the ability of our method on real OCT images.

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  • IPEN-DOC 26445

    LEMOS, F.S.; PEREIRA, J.X.; CARVALHO, V.F.; BERNARDES, E.S. ; CHAMMAS, R.; PEREIRA, T.M.; CARVALHO, R.S.; LUISETTO, R.; EL-CHEIKH, M.C.; CALIL-ELIAS, S.; OLIVEIRA, F.L.. Galectin-3 orchestrates the histology of mesentery and protects liver during lupus-like syndrome induced by pristane. Scientific Reports, v. 9, 2019. DOI: 10.1038/s41598-019-50564-8

    Abstract: Galectin-3 (Gal-3) controls intercellular and cell-extracellular matrix interactions during immunological responses. In chronic inflammation, Gal-3 is associated with fibrotic events, regulates B cell differentiation and delays lupus progression. Gal-3 deficient mice (Lgals3−/−) have intense germinal center formation and atypical plasma cell generation correlated to high levels IgG, IgE, and IgA. Here, we used pristane (2,6,10,14-tetramethylpentadecane) to induce lupus-like syndrome in Lgals3−/− and Lgals3+/+ BALB/c mice. Mesentery and peritoneal cells were monitored because promptly react to pristane injected in the peritoneal cavity. For the first time, mesenteric tissues have been associated to the pathogenesis of experimental lupus-like syndrome. In Lgals3+/+ pristane-induced mice, mesentery was hallmarked by intense fibrogranulomatous reaction restricted to submesothelial regions and organized niches containing macrophages and B lymphocytes and plasma cells. In contrast, Lgals3−/− pristane-treated mice had diffuse mesenteric fibrosis affecting submesothelium and peripheral tissues, atypical M1/M2 macrophage polarization and significant DLL1+ cells expansion, suggesting possible involvement of Notch/Delta pathways in the disease. Early inflammatory reaction to pristane was characterized by significant disturbances on monocyte recruitment, macrophage differentiation and dendritic cell (DC) responses in the peritoneal cavity of pristane-induced Lgals3−/− mice. A correlative analysis showed that mesenteric damages in the absence of Gal-3 were directly associated with severe portal inflammation and hepatitis. In conclusion, it has suggested that Gal-3 orchestrates histological organization in the mesentery and prevents lupoid hepatitis in experimental lupus-like syndrome by controlling macrophage polarization, Notch signaling pathways and DC differentiation in mesenteric structures.

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  • IPEN-DOC 26444

    YORIYAZ, HELIO ; BRANCO, ISABELA S.L. ; ALMEIDA, ISABEL P.; FONSECA, GABRIEL P.. Fundamentos de transporte e cálculo de dose em tratamentos com feixes de prótons / Fundamentals of transport and dose calculation in proton beam therapy. Revista Brasileira de Física Médica, v. 13, n. 1, p. 109-115, 2019. DOI: 10.29384/rbfm.2019.v13.n1.p109-115

    Abstract: Este artigo de revisão apresenta um breve histórico, com os principais fatos da evolução da terapia com feixe de prótons, seguido de uma descrição das principais características dosimétricas apresentadas em faixas de energia utilizadas em terapia. É feita uma breve comparação entre a protonterapia e as demais modalidades de radioterapia com feixe de fótons. Também estão descritos alguns códigos de Monte Carlo atualmente utilizados na simulação do transporte de prótons no meio e suas peculiaridades.

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  • IPEN-DOC 26443

    SILVA, FELIPE D. ; OLIVEIRA, JOÃO E. ; FREIRE, RENAN P. ; SUZUKI, MIRIAM F. ; SOARES, CARLOS R. ; BARTOLINI, PAOLO . Expression of glycosylated human prolactin in HEK293 cells and related N‑glycan composition analysis. AMB Express, v. 9, n. 1, p. 1-11, 2019. DOI: 10.1186/s13568-019-0856-8

    Abstract: Prolactin (PRL) is a hormone produced by the pituitary gland with innumerable functions, such as lactation, reproduction, osmotic and immune regulation. The present work describes the synthesis of hPRL in human embryonic kidney (HEK293) cells, transiently transfected with the pcDNA-3.4-TOPO® vector carrying the hPRL cDNA. A concentration of ~ 20 mg/L, including glycosylated (G-hPRL) and non-glycosylated (NG-hPRL) human prolactin, was obtained, with ~ 19% of G-hPRL, which is higher than that observed in CHO-derived hPRL (~ 10%) and falling within the wide range of 5–30% reported for pituitary-derived hPRL. N-Glycoprofiling analysis of G-hPRL provided: (i) identification of each N-glycan structure and relative intensity; (ii) average N-glycan mass; (iii) molecular mass of the whole glycoprotein and relative carbohydrate mass fraction; (iv) mass fraction of each monosaccharide. The data obtained were compared to pituitary- and CHO-derived G-hPRL. The whole MM of HEK-derived G-hPRL, determined via MALDI–TOF-MS, was 25,123 Da, which is 0.88% higher than pit- and 0.61% higher than CHO-derived G-hPRL. The main difference with the latter was due to sialylation, which was ~ sevenfold lower, but slightly higher than that observed in native G-hPRL. The “in vitro” bioactivity of HEK-G-hPRL was ~ fourfold lower than that of native G-hPRL, with which it had in common also the number of N-glycan structures.

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  • IPEN-DOC 26442

    SANTOS, O.C.B.; VANIN, V.R.; MAIDANA, N.L.; MARTINS, M.N.; TABACNIKS, M.H.; RODRIGUES, C.L.; SILVA, T.F.; SANTOS, A.D.; BARROS, S.F.; GARCIA-ALVAREZ, J.A.; KOSKINAS, M.F. ; FERNANDEZ-VAREA, J.M.; PINDZOLA, M.S.. Experimental and theoretical cross sections for K-shell ionization of 52Te, 73Ta, and 83Bi by electrons with energies up to 100 keV. Physical Review A, v. 100, n. 2, p. 022703-1 - 022703-9, 2019. DOI: 10.1103/PhysRevA.100.022703

    Abstract: In this work we present a combined experimental and theoretical study of K-shell ionization by electrons with energies close to the threshold. The ionization cross sections of the K shells of Te, Ta, and Bi atoms have been measured up to 100 keV with uncertainties ranging from 4% to 8%. In turn, calculations have been done using the subconfiguration average distorted-wave (SCADW) method, which includes the full two-body retarded electromagnetic interaction between the projectile and target electrons. The predictions of the SCADW method are in good agreement with the experimental data. In contrast, theoretical cross sections based on first-order perturbation theory where the transverse interaction is computed with plane waves instead of distorted waves underestimate the SCADW values as well as the experimental data. The difference between the two investigated ab initio formalisms grows with atomic number, being 3% for Te, 15% for Ta, and 25% for Bi. An additional comparison of both theoretical approaches with recent measurements for Au K supports the conclusion that the SCADW method reproduces well the experimental K-shell ionization cross section of atoms with intermediate to large Z near the threshold.

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  • IPEN-DOC 26405

    FERREIRA, THIAGO DOS SANTOS . Compósitos Si3N4-TiN para aplicações estruturais / Si3N4-TiN composites for structural applications . 2019. Dissertação (Mestrado em Tecnologia Nuclear) - Instituto de Pesquisas Energéticas e Nucleares - IPEN-CNEN/SP, São Paulo. 103 p. Orientador: Cecilia Chaves Guedes e Silva. DOI: https://doi.org/10.11606/D.85.2019.tde-06112019-110637

    Abstract: O nitreto de silício (Si3N4) é um material utilizado em diversas aplicações estruturais devido à suas ótimas propriedades mecânicas inclusive a altas temperaturas, como elevada dureza e resistência mecânica, além de alta resistência ao choque térmico e ao desgaste. Visando ampliar seu campo de aplicação, busca-se a melhoria da tenacidade à fratura do material e a simplificação de seu processamento. A produção de compósitos cerâmicos contendo o Si3N4 como matriz cerâmica e uma segunda fase como reforço tem sido estudada por gerar o aumento da tenacidade à fratura. No presente trabalho, estudou-se a influência de diferentes percentuais de TiN (até 30% em massa) na matriz de Si3N4, contendo Al2O3 e Y2O3 (5% em massa de cada) como aditivos. Os compósitos cerâmicos foram avaliados quanto ao comportamento de densificação, microestrutura, propriedades mecânicas e resistência à oxidação. Amostras foram obtidas por prensagem uniaxial e isostática, e sinterizadas com baixa pressão de nitrogênio em duas condições (1750°C/1 hora e 1815°C/1 hora). As composições foram caracterizadas pelo estudo das densidades relativas (geométrica e aparente pelo método de Arquimedes), porosidade e perda de massa. A densidade das composições atingiu valores entre 97,0 e 98,0% da densidade teórica, com porosidade aparente inferiores a 0,5%, comprovando a eficiência dos aditivos de sinterização. O aumento da quantidade de nitreto de titânio no compósito cerâmico ocasionou uma tendência de redução da densidade relativa e de aumento da porosidade aparente. As análises por difração de raios X, MEV e EDS mostraram a presença da fase TiN dispersa na matriz de β-Si3N4, com a presença de fase amorfa intergranular. O método da impressão Vickers foi utilizado para medição da dureza e da tenacidade à fratura. A dureza medida apresentou valores entre 12,5 e 13,2 GPa, condizente com os valores apresentados pelo material monolítico, enquanto a tenacidade à fratura variou entre 6,3 e 9,3 MPa.m1/2, aumentando com a proporção de TiN no compósito cerâmico. A resistência à flexão, obtida pelo ensaio de flexão biaxial do disco apoiado em três esferas, apresentou o mesmo comportamento da tenacidade à fratura, atingindo 397,4 MPa no compósito contendo 30% de TiN e sinterizado a 1750°C, condição na qual os valores de resistência foram superiores. O estudo de oxidação foi avaliado submetendo as amostras a tratamento térmico ao ar a 1400°C por até 64 horas e apresentou valores de ganho de massa por área entre 0,7 e 6,4 mg/cm2, crescente em função do percentual de TiN presente no compósito e do tempo de ensaio. As camadas superficiais das amostras também foram analisadas por difração de raios X, MEV e EDS, identificando a presença do β-Si3N4, da SiO2 (cristobalita α), do TiO2 (rutilo), Y2Ti2O7 e Y2Si2O7 (Keiviite). A presença destas fases após a oxidação indica que ocorreu a liberação de N2 a partir do Si3N4 e do TiN, e a reação do O2 do ambiente com os elementos da fase vítrea presente nos contornos de grãos. Conforme esperado ocorreu a formação de uma camada superficial de TiO2 (rutilo), seguida por uma camada de SiO2 contendo precipitados compostos pelo óxido de titânio-ítrio e pelo silicato de ítrio, formados a partir dos cátions provenientes dos aditivos de sinterização.

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  • IPEN-DOC 23190

    QUINTO JUNIOR, JOSE ; AMARAL, MARCELLO M. ; FRANCCI, CARLOS E.; ANA, PATRICIA A. ; MORITZ, ANDREAS; ZEZELL, DENISE M. . Evaluation of intra root canal Er,Cr:YSGG laser irradiation on prosthetic post adherence. Journal of Prosthodontics, v. 28, n. 1, p. e181-e185, 2019. DOI: 10.1111/jopr.12609

    Abstract: Purpose: In clinical prosthetics procedures, including endodontics and post fixation, the presence of a smear layer can reduce the post bond strength. An Er,Cr:YSGG laser, which emits at 2780 nm, can promote a smear-layer-free surface due to the ablation process. Considering these aspects, the purpose of this work was to evaluate the influence of Er,Cr:YSGG laser irradiation using either a radial or an axial fiber tip on the bond strength of three resin cements to the fiber-reinforced composite posts. Materials and Methods: Ninety recently extracted single rooted human teeth had their root canal instrumented and were randomly distributed into nine experimental groups, in which three resin cements (total-etching Variolink II, self-etching Panavia F, and self-adhesive RelyX Unicem Aplicap) and three root canal treatments (no treatment, laser irradiation using the radial fiber tip, laser irradiation using the axial fiber tip) were used. Specimens were then sectioned into three sections (cervical, middle, and apical thirds) with two slices on each section. A push-out test was performed on each slice, and the values were recorded as MPa. The push-out data were analyzed by a Ryan-Joiner normality test followed by a two-way ANOVA test and Tukey pairwise comparison. The statistical analysis was performed on each third section separately, with a 5% significance level. Results: Laser irradiation with axial fiber tip significantly increased the post bond strength of RelyX Unicem Aplicap on middle third of specimens (p < 0.001) when compared to other root canal treatments (unlased or irradiated with radial tip). Considering the Panavia resin cement, laser irradiation with either axial or radial tips promoted a significant increase on the post bond strength of middle third when compared to unlased specimens (p < 0.001); however, laser irradiation did not influence the post bond strength of Variolink resin cement. Conclusions: The use of the Er,Cr:YSGG laser for clinical prosthetics procedures enhances the post bond strength of Panavia and RelyX Unicem Aplicap resin cements, mainly at middle third of roots, and does not interfere with the bond strength of Variolink resin cement. For the RelyX Unicem Aplicap system, the use of axial tip is most advantageous and can be recommended for future clinical application.

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  • IPEN-DOC 26440

    SOUZA, ARMANDO C. de; CIONE, FRANCISCO C. ; SILVA, ALINE C. da; GOUVEA, ADRIANA de F.G.; MACHADO, NOE G.P. ; RAELE, MARCUS P. ; ROSSI, JESUALDO L. . Evaluation of a metal-organic composite (tungsten-lignin) for attenuation of gamma radiation. Materials Research, v. 22, S1, p. 1-5, 2019. DOI: 10.1590/1980-5373-MR-2019-0045

    Abstract: The objective of this work was to use tungsten and lignin as precursors to obtain a metal-organic composite tungsten-lignin (W-Lig) using different sintering temperatures. Tungsten is a refractory metal and it was selected for the composite since it is widely used for high-energy radiation shielding as it has an excellent absorption cross section for thermal neutrons. Lignin extracted from lignocelluloses biomass and it was selected to be the organic precursor for the composite due to its multiple applications. Analysis of the composite was performed after sintering processes, using a 3D optical surface profiler and measurement of the gamma radiation attenuation coefficient using cobalt source (Co-60). Metalorganic composites in ratios of W2.5%Lig and W5%Lig (in mass % of lignin) were used. The gradient of the attenuation coefficient differed when standard tungsten and the composites of W2.5%Lig and W5%Lig were compared. Therefore, the attenuation coefficient between unobstructed free radiation and the W5%Lig 90 ºC composite showed a gradient of about 43% in the two characteristic Co-60 energy peaks, with a sample thickness of 0.679 cm the calculated linear attenuation coefficient was 0.832 cm-1.

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  • IPEN-DOC 26439

    GARDA, GIANNA M.; FILGUEIRA, DIEGO A.; PUGLIESI, REYNALDO ; PEREIRA, MARCO A.S. ; SAYEG, ISAAC J.. Estudo da mineralização de cobre em basaltos do Grupo Serra Geral, utilizando difratometria de raios X, microscopia eletrônica de varredura-espectroscopia por energia dispersiva e tomografia com nêutrons / Study of copper mineralization in basalts of the Serra Geral Group, using X-ray diffraction, scanning electron microscopy-energy dispersive spectroscopy, and neutron tomography. Geologia USP - Série Científica, v. 19, n. 3, p. 111-127, 2019. DOI: 10.11606/issn.2316-9095.v19-152501

    Abstract: Mineralizações de cobre do tipo Michigan ocorrem nos derrames basálticos do Grupo Serra Geral na região de Nova Prata do Iguaçu, sudoeste do estado do Paraná. Nessas mineralizações, o cobre nativo é o principal mineral de minério e, com a alteração supérgena, transforma-se em óxidos de cobre, malaquita e crisocola, sendo esta encontrada na forma de um precipitado gelatinoso que preenche amígdalas e impregna fraturas no basalto, além de recobrir minerais secundários e outros produtos de alteração. Neste estudo, foram utilizadas as técnicas de difratometria de raios X e microscopia eletrônica de varredura-espectroscopia por energia dispersiva (MEV-EDS) para a caracterização do grau de cristalinidade e composição química da crisocola e a identificação de outros materiais hidrogenados, como subsídio para o imageamento 3D por tomografia com nêutrons. A crisocola destacou-se como um eficiente atenuador de nêutrons, obtendo-se coeficiente de atenuação linear da ordem de 0,8–1,3 cm-1, ao passo que, para o corpo de minério (basalto), obteve-se 0,5–0,6 cm-1. O contraste entre os coeficientes permitiu a obtenção de imagens tomográficas e filmes de boa resolução, em que se pôde visualizar a distribuição da crisocola na amostra de basalto e estimar como fração volumétrica de crisocola no corpo de minério valores entre 0,9 e 1,4%, obtendo-se o valor de 7,8% em volume de crisocola para uma das amostras. A utilização integrada das três técnicas analíticas demonstrou que esta pode ser uma ferramenta para avaliação do potencial mineral nas fases iniciais da prospecção mineral, especialmente quando as substâncias de interesse são ricas em hidrogênio.

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  • IPEN-DOC 26438

    MEDINA, MIDILANE S. ; CARVALHO, SABRINA G.M. ; MUCCILLO, ELIANA N.S. ; MUCCILLO, REGINALDO . Enhancement of the ionic conductivity in electric field-assisted pressureless sintered BITIVOX solid electrolytes. Ceramics, v. 2, n. 3, p. 502-513, 2019. DOI: 10.3390/ceramics2030038

    Abstract: Bi4V1.8Ti0.2O11 (BITIVOX) ceramic pellets, prepared with powders obtained by a sol gel technique, were sintered either conventionally at 800 C/8 h or by applying an AC electric voltage, limiting the electric current through the pellets. Electric voltages were applied isothermally at 700 C and 800 C during 5 min in the green pellet positioned in the sample holder of a dilatometer for monitoring thickness variation. The BITIVOX pellets shrank 13.6% after applying 200 V cm􀀀1 at 800 C and 10.4% heating to 800 C for 8 h. Thermal analysis and X-ray di raction of the powders were performed to evaluate the crystallization temperature and the structural phase, respectively. The electrical behavior of the sintered BITIVOX pellets was analyzed by the impedance spectroscopy technique, showing that the sample flash sintered at 800 C/5 min had lower bulk resistivity than the sample conventionally sintered at 800 C/8 h. The surfaces of the sintered pellets were observed in a scanning electron microscope showing similar grain sizes and pore content in all sintered samples.

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  • IPEN-DOC 26437

    REIS, SHIRLEY L. ; CARVALHO, SABRINA G.M. ; MUCCILLO, ELIANA N.S. ; MUCCILLO, REGINALDO . Electrical behavior of electric field-assisted pressureless sintered ceria-20 mol% samaria. Ceramics, v. 2, n. 2, p. 385-392, 2019. DOI: 10.3390/ceramics2020030

    Abstract: CeO2:20 mol% Sm2O3 green ceramic pellets were sintered conventionally at 1500 C/2 h and flash sintered by applying a 200 V cm􀀀1 electric field at 800 C, 1000 C and 1200 C. The thickness shrinkage of the pellets was followed bythe specimen being positioned inside a dilatometer adapted with platinum electrodes and terminal leads connected to a power supply for application of the electric voltage. The microstructure of the surfaces of the sintered samples were observed in a scanning electron microscope. The electrical properties were evaluated by the impedance spectroscopy technique in the 5 Hz–13 MHz frequency range from 210 C to 280 C. The main results show that (i) the final shrinkage level is nearly independent of the temperature when the electric field is applied and slightly better than that of the 1500 C sintered pellet, and (ii) the bulk conductivity of the sample flash sintered at 1200 C is similar to that of the sample sintered at 1500 C. The availability of a pathway for the electric current pulse derived from the applied electric field is proposed as the reason for the achieved shrinkages. Scavenging of the grain boundaries by Joule heating is proposed as the reason for the improved oxide ion bulk conductivity.

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  • IPEN-DOC 26436

    BETINI, EVANDRO G. ; GOMES, MAURILIO P. ; MUCSI, CRISTIANO S. ; ORLANDO, MARCOS T.D.; LUZ, TEMISTOCLES de S.; AVETTAND-FENOEL, MARIE-NOELLE; ROSSI, JESUALDO L. . Effect of nitrogen addition to shielding gas on cooling rates and in the microstructure of thin sheets of duplex stainless steel welded by pulsed gas tungsten arc welding process. Materials Research, v. 22, 1, p. 1-9, 2019. DOI: 10.1590/1980-5373-MR-2019-0247

    Abstract: The effect of the nitrogen content in the shielding gas and its effect on temperature distributions at the welded zone of thin sheets of duplex stainless steel have been evaluated. The duplex stainless steels have many features due to unique microstructural combination of austenite and ferrite grains. The phase balance can be easily shifted depending on the welding parameters. Two sheets were welded using pure argon and pure argon plus 2% of nitrogen as shielding gas. The thermal profile had shown that N2-supplemented shielding gas lead to higher peaks of temperature using similar welding parameters. Microstructural examination showed that the austenite phase in the weld increased with the presence of nitrogen in the shielding gas. The added nitrogen promoted primary austenite formation and slightly increases the microhardness at the solidified zone. Microhardness mapping and metallographic imaging presented information about microstructures, confirming the formation of secondary phases during thermal cycle in the temperature range 850 °C and 950 °C. Control of ferrite amounts in the welds is essential mainly to improve mechanical properties and corrosion resistance of welding zones.

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  • IPEN-DOC 26435

    SALGADO, MARIA de F.; CARVALHO, IURE S.; SANTOS, RAFAEL S.; PORTO, JOÃO A.S.; CORREA, OLANDIR V. ; RAMANATHAN, LALGUDI V. ; BRANDIM, AYRTON de S.; LINS, VANESSA F.C.. Effect of oxygen partial pressure on oxidation behavior of ferritic stainless steel AISI 441 at high temperatures. Engineering Failure Analysis, v. 105, p. 215-226, 2019. DOI: 10.1016/j.engfailanal.2019.07.011

    Abstract: In this investigation the oxidation behavior of AISI 441 stainless steel (SS) in the range from 850 °C to 950 °C was determined during 50 h in two different atmospheres: (a) synthetic air in a tubular oven; (b) argon with 1 ppm of O2 in a thermal balance. The oxidation kinetics was determined from the measured mass change as a function of oxidation time. Examination of the microstructure of the oxides and determination of their chemical composition were performed by using scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS) and glancing angle X-ray diffraction (GAXRD). Chemical analyses showed that films formed on the AISI 441 steel surface consisted mostly of chromium oxide but manganese, iron, titanium and silicon oxides were found in the oxidized layer. In synthetic air, the steel oxidation rate increased gradually as the temperature increased, but in the argon atmosphere with 1 ppm of oxygen, the highest oxidation rate was observed at 900 °C and the lowest at 950 °C.

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  • IPEN-DOC 26171

    AFFA, GABRIEL B. ; PECEQUILO, BRIGITTE R.S. . Preliminary results of natural radioactivity evaluation in underground waters of the city of Campos do Jordao, SP, Brazil. In: ABEN (Ed.) INTERNATIONAL NUCLEAR ATLANTIC CONFERENCE, October 21-25, 2019, Santos, SP. Proceedings... Rio de Janeiro, 2019. p. 672-680.

    Abstract: Twenty-eight 5-liter samples were collected during the year of 2018 on four different campaings (January, April, August and December) for seven selected sources (SP-123, Britania, Amizade, Dom Bosco, Volta Fria, Simao and Renato) of easy and free access to the population on the city of Campos do Jordão, SP, Brazil. Samples were concentrated from 1L to 50 mL of which 4 mL pipetted on 60 mm diameter stainless steel planchet were analyzed with a Berthold’s PC-controlled 10-channel Low-level Alpha-Beta Counter LB 770 Win in three 120-minute counting cycles. Preliminary results have shown low alpha and beta activity concentrations for all sources with values ranging between 0.0288 Bq/L ± 0.0036 Bq/L and 0.1059 Bq/L ± 0.0118 Bq/L for alpha activity and between 0.0371 Bq/L ± 0.005 Bq/L and 0.1352 Bq/L ± 0.0148 Bq/L for beta activities. Results showed a tendency of higher concentrations during periods of drier weather. All obtained values are below the limits of 0.5 Bq/L and 1 Bq/L, respectively for alpha and beta activity concentrations, recommended by the 2017 WHO Guideline on Drinking Water Management.

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  • IPEN-DOC 26170

    GERALDES, LARISSA L.; BORRELY, SUELI I. . Hyalella azteca used for the evaluation of cyanotoxins before and after irradiation with electron beam: preliminary results. In: ABEN (Ed.) INTERNATIONAL NUCLEAR ATLANTIC CONFERENCE, October 21-25, 2019, Santos, SP. Proceedings... Rio de Janeiro, 2019. p. 667-671.

    Abstract: The occurrence of cyanobacteria blooms in water bodies used for human consumption represents risks to the population due to the ability of these microorganisms to produce metabolites, known as cyanotoxins. They can be classified as hepatotoxins, dermatotoxins and neurotoxins. Cyanotoxins are water soluble and are not removed by the conventional water treatment system for public supply. Several studies have been carried out to minimize this type of contamination. Electron beam irradiation has been applied in aqueous solution containing the cyanobacteria of the genus Microcystis, in 40% of growth medium content and applying 2.5 kGy. The amphipod Hyalella azteca was the aquatic organism selected for the evaluation of the potential of cyanotoxins risks to the biota of the reservoirs where the cyanobacteria blooms occurs, being demonstrated high toxicity.

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  • IPEN-DOC 26169

    FUNGARO, DENISE A. ; SILVA, PAULO S.C. da ; GROSCHE, LUCAS C. ; BIBIANO, RAMIRO H.N.. Assessment of natural radioactivity levels in flue gas desulfurization gypsum and clinker samples. In: ABEN (Ed.) INTERNATIONAL NUCLEAR ATLANTIC CONFERENCE, October 21-25, 2019, Santos, SP. Proceedings... Rio de Janeiro, 2019. p. 660-666.

    Abstract: Coal Combustion Products (CCPs) are the by-products generated from burning coal in coal-fired power plants. which includes fly ash, bottom ash, boiler slag and flue gas desulfurization wastes. These by-products contain trace quantities of naturally occurring radionuclides from the uranium and thorium series, as well as other naturally occurring radionuclides such as 40K derived from the original coal matrix that tend to become enriched in the ashes. Flue gas desulfurization gypsum (FGD gypsum) is the hydrated calcium sulphate produced when SOx is removed from gases produced during the combustion of coal. FGD gypsum can be used as an alternative material to natural gypsum as retarder additive for Portland cement. In this work, analysis of the radioactive content in FGD gypsum samples were performed to determine if beneficial uses of this CPP in building materials could be of radiological concern. Analysis of clinker sample was also performed. The FGD gypsum samples were collected at Presidente Médici thermoelectric power plant, located in Candiota, RS. The radioactive content of 238U, 232Th, 226Ra, 228Ra, 210Pb and 40K was determined using Neutron activation analysis and Gamma-ray spectrometry. The specific activities (Bq kg−1) were compared to results from literature studies including different building materials and coal ashes specific activities.

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  • IPEN-DOC 26431

    SILVA, DIEGO S. da ; WETTER, NIKLAUS U. ; KASSAB, LUCIANA R.P.; ROSSI, WAGNER de ; ARAUJO, MARIANA S. de . Double line waveguide amplifiers written by femtosecond laser irradiation in rare-earth doped germanate glasses. Journal of Luminescence, v. 217, p. 1-5, 2020. DOI: 10.1016/j.jlumin.2019.116789

    Abstract: We report the production of active double waveguides in Er/Yb doped GeO2-PbO glasses, by direct femtosecond laser writing. The glasses were produced using the melt-quenching technique and the active waveguides were written using 30 fs laser pulses, at 800 nm, with writing speed of 0.06 mm/s and pulse energy of 32 μJ. The photo-induced negative refractive index change was of 􀀀 7.4 � 10􀀀 3. The Er/Yb doped sample showed a relative gain (signal enhancement of 7.5 dB/cm, for 105 mW of 980 nm pump power. The relative gain compensates both, the propagation losses and the absorption losses, and a positive maximum internal gain of 4.6 dB/cm can be obtained at the signal wavelength of 1550 nm. The results obtained in present work demonstrate that Er/Yb glasses are promising materials for the fabrication of integrated amplifiers, lossless components and lasers based on germanate glasses.

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  • IPEN-DOC 26168

    BOIANI, NATHALIA F. ; VILLARDI, BRUNO D.Q.; GARCIA, VANESSA S.G. ; BORRELY, SUELI I. . Electron beam irradiation of combined pharmaceuticals: propranonol and fluoxetine and related ecotoxicity. In: ABEN (Ed.) INTERNATIONAL NUCLEAR ATLANTIC CONFERENCE, October 21-25, 2019, Santos, SP. Proceedings... Rio de Janeiro, 2019. p. 641-649.

    Abstract: There are serious evidences that justify the search for treatment technologies or processes combination for the improvement of decomposition for dozens of pharmaceuticals in wastewaters. Electron beam irradiation may play an important role in this scenario and relatively low doses have been reported for such purposes. The aim of the present study was to evaluate the toxic response of the crustacean Daphnia similis exposed to individual and combined pharmaceuticals. Several experimental trials of an acute immobilization test were performed with a mixture of pharmaceuticals composed of fluoxetine hydrochloride (Prozac®), and propranolol. Single pharmaceuticals were first tested separately. Toxicity of binary mixture was then assessed using five concentrations and 5 percentages of each substance in the mixture (0, 25, 50, 75, and 100%). Acute EC50% values ranged from 5.0 to 7.4 for fluoxetine and from 11.3 to 13.7 for propranolol. In mixture, values ranged from 6.4 to 9.8. Fluoxetine was more toxic for D.similis than propranolol. The different pharmaceuticals concentrations employed in a mixture showed no difference in toxicity values. When electron beam irradiation was applied, approximately 80% of acute effects were reduced at 5 kGy, and the mixture containing a higher percentage of fluoxetine, also showed a greater reduction of toxicity.

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  • IPEN-DOC 26167

    SOUFIA, LAYLA B. ; GOUVEA, PAULO F. de M. ; SILVA, PAULO S.C. da . Determination of mineral elements and traces present in the fractions of the humic substances of Peruíbe Black Mud. In: ABEN (Ed.) INTERNATIONAL NUCLEAR ATLANTIC CONFERENCE, October 21-25, 2019, Santos, SP. Proceedings... Rio de Janeiro, 2019. p. 628-640.

    Abstract: Peruíbe Black Mud (PBM) found in the city of Peruíbe in state of São Paulo, is known for its curative and anti-inflammatory properties. Considered as a material with high cation exchange capacity, microbiological analyzes revealed a large amount of sulfate reducing bacteria and high content of organic material from the biological-metabolic process. In order to provide data that may be useful to understand its therapeutic effects and secondly to certify its quality for use in medical treatments it is necessary to determine the presence of trace elements and minerals present in the different fractions of humic substances and, for this, the technique of neutron activation analysis (INAA) associated with gamma spectrometry was used. Results demonstrate that elements such as Cr and Zn may be concentrated in the humic fraction over the mineral fraction of the mud.

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  • IPEN-DOC 26166

    ARMELIN, MARIA J.A. ; MOREIRA, EDSON G. . Importance of the neutron activation analysis for the determination of elements in different organic materials. In: ABEN (Ed.) INTERNATIONAL NUCLEAR ATLANTIC CONFERENCE, October 21-25, 2019, Santos, SP. Proceedings... Rio de Janeiro, 2019. p. 621-627.

    Abstract: Instrumental Neutron Activation Analysis (INAA) was the analytical technique used to determine the concentrations of As, Ba, Br, Ca, Ce, Cl, Co, Cr, Fe, La, K, Mg, Mn, Pr, Sb, Sm, V and Zn in the following materials: petroleum, rubber, plastics and petroleum coke. The precision of the results were mostly between 1 and 20%. The technique is non-destructive and fast for Cl, Cu, Mg and V analyses. For this reason, INAA showed to be a good option to be applied in organic matrices.

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  • IPEN-DOC 26165

    MAIHARA, VERA A. ; OLIVEIRA, MUNIQUE A.P. ; OLIVEIRA, DAVI F. . Characterization of nutrient composition in functional foods. In: ABEN (Ed.) INTERNATIONAL NUCLEAR ATLANTIC CONFERENCE, October 21-25, 2019, Santos, SP. Proceedings... Rio de Janeiro, 2019. p. 614-620.

    Abstract: Functional foods contain in their composition some biologically active substances that when added to a usual diet produce metabolic or physiological processes, resulting in disease risk reduction and health maintenance. Acai, green tea, quinoa, chia, flaxseed and goji berry are examples functional foods due to their health benefits. The concentrations of Br, Ca, Co, Cl, K, Fe, Mn, Mg, Na, Rb and Zn were determined in quinoa, chia and flaxseed samples by Neutron Activation Analysis. The obtained results were discussed using the Dietary Reference Intake (DRI) for essential elements provided by the Institute of the Medicine of National Academy and a comparison between the different functional foods was carried out.

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  • IPEN-DOC 26164

    SOUZA, LUCAS S.G. de ; SILVA, PAULO S.C. da . Uranium determination in tap water by INAA. In: ABEN (Ed.) INTERNATIONAL NUCLEAR ATLANTIC CONFERENCE, October 21-25, 2019, Santos, SP. Proceedings... Rio de Janeiro, 2019. p. 594-601.

    Abstract: Uranium can exist in the water as a result of soil leaching or technological processes (mining and processing of phosphate minerals to fertilizer production). The INAA (instrumental neutron activation analysis) usually is used to determination of trace elements through the conversion of stable nuclei to another via nuclear reactions. The present work used INAA method for determination of U in water samples. The goals are validate a methodology to determine U in water samples, apply this methodology and determinate the physical chemical parameters pH, total solids and alkalinity in tap waters samples. The validation was stablished based on varying the irradiation and counting times. A-one-liter sample with 87 g of U was prepared from the standard solution of U 1000 mg L􀀀1 (SPEX CERTIPREP). From this prepared solution was taken ten samples of 100 mL each. After complete evaporation at 100oC in hot plate and at 60oC in infrared lamp, the ten samples were irradiated in the IEA-R1 nuclear research reactor. Two samples from di erent regions were collected for determination of pH, total solids, alkalinity and U concentration.

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  • IPEN-DOC 26163

    CARVALHO, GLAUBER M. de ; SEMMLER, RENATO ; MENEZES, MARIO O. de . Development of a semantic layer for a data repository prototype for neutron activation analysis domain data. In: ABEN (Ed.) INTERNATIONAL NUCLEAR ATLANTIC CONFERENCE, October 21-25, 2019, Santos, SP. Proceedings... Rio de Janeiro, 2019. p. 584-593.

    Abstract: In order to provide greater transparency for scienti c research and the results achieved, a great e ort is ongoing to make available scienti c data repositories, which allow for di erent researchers to validate, reproduce and reuse third party scienti c data. With the always increasing use of technology in all kinds of scienti c facilities, a growing amount of data is collected even from simple experiments. This scenario presents a new paradigm: the understanding of third party data easily found on data repositories. Consequently, being able to do useful searches on these data repositories poses a new challenge for traditional search engines. In this work, the approach taken to help solve these problems was to propose a semantic layer for scienti c data repository. By using ontologies, with appropriated integration of traditional search mechanisms, it will be easier for users to nd related data that could be used in their work, improving the overall scienti c yield. In order to achieve this goal, a ontology was developed, using the Prot eg e software, for the Neutron Activation Analysis (NAA) data domain. This ontology was validated by experts from NAA Laboratory of the Reactor Research Center (CERPq) at the Nuclear and Energy Research Institute (IPEN-CNEN/SP). A prototype of a semantic data repository is, thus, being developed using the Django web development framework. RDFlib, a software library written in Python is being used to allow the integration of semantic operations, based on the NAA ontology, with the relational database layer provided by Django.

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  • IPEN-DOC 26162

    TICIANELLI, REGINA B. ; ZAHN, GUILHERME S. ; SILVA, PAULO S.C. da ; GENEZINI, FREDERICO A. . Radionuclide analysis of the IEA-R1 pool water. In: ABEN (Ed.) INTERNATIONAL NUCLEAR ATLANTIC CONFERENCE, October 21-25, 2019, Santos, SP. Proceedings... Rio de Janeiro, 2019. p. 579-583.

    Abstract: IEA-R1 is a 5MW pool-type research reactor built in the late 1950's. In the last years, it operates at 4.5MW for 8h on Mondays, Tuesdays and Wednesdays. In every day of operation, a sample is taken from the pool water both before starting the reactor and at the end of the day and analyzed in an HPGe detector, in order to verify for possible problems with the fuel elements or other issues. In this work, the results obtained in these analyses spanning for some months are discussed regarding the radionuclides frequently identi ed and the dependence of their activities with time.

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  • IPEN-DOC 26161

    BARIA, ROGÉRIO ; WATANABE, SHIGUEO ; MUNITA, CASIMIRO S. ; SILVA, PAULO S. ; TATUMI, SONIA H.. Comparative study of the determination of (238)U, (232)TH, and (40)K in geological samples using INAA and gamma-ray spectroscopy. In: ABEN (Ed.) INTERNATIONAL NUCLEAR ATLANTIC CONFERENCE, October 21-25, 2019, Santos, SP. Proceedings... Rio de Janeiro, 2019. p. 569-578.

    Abstract: Physical dating methods including thermoluminescence (TL), optically stimulated luminescence (OSL) and electron paramagnetic resonance (EPR) require the precise determination of the dose rate of experimental ionizing radiation. To determine the age of sediment by TL and OSL or EPR, it is necessary to accurately determine the exact mass fractions of 238U, 232Th, and 40K, since these concentrations are used in the calculation of the annual radiation dose. This work presents a comparative study of the determination of 238U, 232Th, and 40K using two analytical techniques: instrumental activation analysis (INAA) and γ-ray spectroscopy. The results presented in this paper are concordant between the two techniques.

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  • IPEN-DOC 26430

    PEREIRA, MARCO A.M.; SILVEIRA, LUCAS M.; NANNINI, FELIX; NEVES, LUCIO P.; PERINI, ANA P.; SANTOS, CARLA J.; BELINATO, WALMIR; SANTOS, WILLIAM S. . Dosimetric evaluation of individuals to 238U series, 232Th series and 40K radionuclides present in Brazilian ornamental rocks using computational simulation. Ecotoxicology and Environmental Safety, v. 173, p. 401-410, 2019. DOI: 10.1016/j.ecoenv.2019.02.038

    Abstract: Granites are widely used in construction and they may be potential sources of ionizing radiation, due to the presence of radionuclides such as 40K and decay products from 238U series and 232Th series. These radionuclides occur in the minerals constituting the rocks. To evaluate the doses in humans exposed to 40K, and decay products from 238U series and 232Th series radiation, a room with dimensions of 4.0 × 5.0 × 2.8m3, with uniformly distributed radiation source on the floor of granitic rocks, was computationally modeled. Adult individuals were represented in the virtual scenario by two virtual anthropomorphic phantoms FASH3 and MASH3, incorporated simultaneously in the software MCNPX 2.7.0. The mean energy deposited on each organ and tissue of FASH3 and MASH3 phantoms was determined using the MCNPX F6 tally (MeV/g/particle), while the photon flux within the room was calculated with the MCNPX F4 tally (MeV/cm2/particle). The organs that obtained the highest conversion coefficients CC[HT] (Sv/Gy) were the red bone marrow (0.94), skin (0.90), breast (0.81) and bladder (0.73) for the FASH3; skin (0.89), gonads (0.88), breast (0.79) and bladder (0.70) for the MASH3. The simulated air absorbed dose rates varied between 23.4 (11%) and 25.8 (12%) nGy/h, and the annual dose rates were 0.10 (6%) and 0.11 (6%) mSv/year. These results presented acceptable statistical uncertainties and they are in agreement with the literature. Fluency of photons pointed to the central region of the room floor as the place of greatest exposure. The results showed that the organs closer to the radiation source had the highest deposited energy values. Based on the annual effective dose data obtained, it was possible to note that the values are within the literature. We believe that the methodology used will allow the investigation of any ornamental material that emits natural radiation.

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  • IPEN-DOC 26429

    SANTOS, MONIQUE C.L. ; NUNES, LIVIA C.; SILVA, LUIS M.G. ; RAMOS, ANDREZZA S.; FONSECA, FABIO C. ; SOUZA, RODRIGO F.B. de ; NETO, ALMIR O. . Direct alkaline anion exchange membrane fuel cell to converting methane into methanol. ChemistrySelect, v. 4, n. 39, p. 11430-11434, 2019. DOI: 10.1002/slct.201902421

    Abstract: Methane is the main constituent of natural gas and can be converted in higher value-added products for electricity cogeneration. It could be used as a solid membrane reactor (SMR) for application in Alkaline Anion-Exchange Membrane Fuel Cell (AAEMFC). The investigation for the conversion of methane was based on sodium borohydride (NaBH4) method using Pt/C Basf, Pd/C, Ni/C as catalysts. The electrocatalysts were prepared with 20 wt% of metals loading on carbon. The X-ray diffraction (XRD) analysis revealed a face-centered cubic structure (FCC) for Pt/C and Pd/C catalysts, was observed Ni/ NiO phases for Ni/C electrocatalyst. The Transmission Electron Microscopy (TEM) exhibited a good dispersion of nanoparticles and some agglomerations on the support, with a mean size of 6.4 nm for Pd/C, 5.7 nm for Ni/C and near to 2 nm size for Pt/C. The experiments with AAEMFC showed that all materials can carry out the reaction spontaneously. Pt/C catalyst presents energy density higher than the other materials. FTIR data suggest that methane was converted into small products organic molecules such as methanol and formate in different potentials for Pt/C, Pd/C, and Ni/C. The products were quantified by Raman spectroscopy. The high conversion efficiency obtained was about 20% at 0.3 V using Pt/C catalyst, the maximum conversion over Pd/C was 17.5% at 0.15 V, associated with the formation of a thin layer of PdO on the catalytic surface. The highest conversion rate (13%) was observed in closed circuit potentials to the short circuit in the cell with Ni/C catalyst. The results suggest that for the selective conversion of methane to methanol are most promising using materials containing Pt or Pd.

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  • IPEN-DOC 26428

    KAISER, THIAGO J.S.; SEMMLER, RENATO ; LIMA, GEAN B. de. Development of a web free software for the absolute efficiency calibration for HPGe type detectors. International Journal of Advanced Engineering Research and Science, v. 6, n. 5, p. 318-327, 2019. DOI: 10.22161/ijaers.6.5.42

    Abstract: The IEA-R1, swimming pool research reactor, from the Institute of Energy and Nuclear Research (IPEN), among other uses, the instrumental neutron activation analysis technique is widely used, and successfully, by the Neutron Activation Laboratory (LAN), using the comparative method. In this method a sample is irradiated simultaneously with a standard. In order to overcome the difficulty of a multi -elementary analysis, because it was necessary to prepare several standards, the k0 method of neutron activation was developed. In method k, the concentration of sample elements is calculated in relation to a comparator element, generally gold. However, for the use of the k0 method, it is necessary to accurately determine the detection efficiency in the energy range of interest and the geometry of the experimental arrangement. In order to circumvent the manual processing of the data in spreadsheets, which could be affected by errors, a free code web software was developed for calibration in absolute efficiency of an HPGe type detector for neutron activation analysis based on the k0. We used the free, low learning curve standardized Python programming language in the eScience project, which is part of the software, and the Django web framework with a simple and intuitive interface. In the system it is possible to register the detectors, radioactive sources and their manufacturers, projects and spectra, attributes necessary to calculate the absolute efficiency of an HPGe type detector. In addition to calculating efficiency, the system plots the graph with the efficiency points, trend curve, with possibility of adjustments, and error bar representing the uncertainties. The system issues reports on spectra and efficiency data for each project. The reports make it possible to check the data as well as its use in other applications. Because it is a web software, its access is allowed from any device with an internet connection. Another result obtained with the system is the reduction of the possibility of errors with the manual treatment of the data in spreadsheets.

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  • IPEN-DOC 26427

    FRANCISCO, L.H.C. ; FELINTO, M.C.F.C. ; BRITO, H.F.; TEOTONIO, E.E.S.; MALTA, O.L.. Development of highly luminescent PMMA films doped with Eu3+β‑diketonate coordinated on ancillary ligand. Journal of Materials Science: Materials in Electronics, v. 30, n. 18, SI, p. 16922-16931, 2019. DOI: 10.1007/s10854-019-01639-9

    Abstract: In this work, [Eu(tta)3(4-picNO)2] and [Eu(dbm)3(4-picNO)] complexes were incorporated on different concentrations (x = 1, 3, 5, 10 and 15%) in PMMA polymeric matrix (4-picNO: 4-Methylpyridine N-oxide) by the solvent casting method, yielding transparent and highly luminescent polymeric films. These materials were analyzed by X-ray diffraction, scanning electron microscopy and by energy dispersive, ultraviolet–visible spectroscopy, luminescence and vacuum ultraviolet–ultraviolet spectroscopies. The luminescence spectra of doped PMMA films are in agreement with an efficient intramolecular diketonate (tta) ligand-to-europium energy transfer. Furthermore, the values of experimental intensity parameters (Ω2,4) for luminescent polymeric materials were quite similar to those ones for isolated complexes, indicating that there is a homogeneous dispersion of Eu3+ complexes in the polymeric matrix, preserving their chemical and structural features. These behavior were also observed from the CIE diagram that show great similarity between the (x,y) coordinates for the doped PMMA samples compared to the isolated β-diketonate complexes with a reddish color tuning. The photostability investigation of the doped PMMA polymeric films and Eu3+ complexes has been also reported.

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  • IPEN-DOC 26426

    BARROS, L.F. ; RIBEIRO, R.V. ; DIAS, M.S. ; MORALLES, M. ; SEMMLER, R. ; YAMAZAKI, I.M. ; KOSKINAS, M.F. . Determination of k0 and Q0 for 74Se, 113In, 186W and 191Ir targets applying covariance analysis. Applied Radiation and Isotopes, v. 154, p. 1-7, 2019. DOI: 10.1016/j.apradiso.2019.108846

    Abstract: In the present work, the determinations of k0 and Q0 for 74Se, 113In, 186W and 191Ir targets were performed. The irradiations were conducted near the core of the IEA-R1 4.5MW swimming-pool nuclear research reactor of the Instituto de Pesquisas Energéticas e Nucleares (IPEN-CNEN/SP – Nuclear and Energy Research Institute), in São Paulo, Brazil. The irradiation position was chosen where the neutron spectrum shape parameter α is very close to zero. For this reason, the correction to be applied for the determination of Q0 is very close to one, thus improving the accuracy of the results. For each experiment, two irradiations were carried out in sequence: the first one with bare samples and the second with a cadmium cover around the samples. All partial uncertainties were considered, applying the covariance matrix methodology. The final results were compared with the literature.

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  • IPEN-DOC 26425

    ALVARENGA, TALLYSON S. ; FREITAS, BRUNO M.; FONSECA, EVALDO S.; PEREIRA, WALSAN W.; CALDAS, LINDA V.E. . Determination of the scattered radiation at the neutron calibration laboratory of IPEN using the Shadow Cone method. Brazilian Journal of Radiation Sciences, v. 7, n. 2B, p. 1-9, 2019. DOI: 10.15392/bjrs.v7i2B.386

    Abstract: Because of the increase in the demand for the calibration of neutron detectors, there is a need for new calibration services. In this context, the Calibration Laboratory of Instituto de Pesquisas Energéticas e Nucleares (IPEN), São Pau-lo, which already offers calibration services of radiation detectors with standard X, gamma, beta and alpha beams, has recently projected a new test laboratory for neutron detectors. This work evaluated the contribution of dispersed neutron radiation in this laboratory, using the Cone Shadow Method and a Bonner Sphere Spectrometer to take the measure-ments at a distance of 100 cm from the neutron source. The dosimetric quantities Ambient Dose Equivalent Rate (Ḣ*(10)) and Ambient Dose Equivalent Conversion Coefficient (h*(10)) were obtained at the laboratory, allowing the calibration of detectors.

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  • IPEN-DOC 26424

    BERBEL, LARISSA O. ; BANCZEK, EVERSON do P.; KAROUSIS, IOANNIS K.; KOTSAKIS, GEORGIOS A.; COSTA, ISOLDA . Determinants of corrosion resistance of Ti-6Al-4V alloy dental implants in an In Vitro model of peri-implant inflammation. PLoS ONE, v. 14, n. 1, p. 1-17, 2019. DOI: 10.1371/journal.pone.0210530

    Abstract: Background Titanium (Ti) and its alloys possess high biocompatibility and corrosion resistance due to Ti ability to form a passive oxide film, i.e. TiO2, immediately after contact with oxygen. This passive layer is considered stable during function in the oral cavity, however, emerging information associate inflammatory peri-implantitis to vast increases in Ti corrosion products around diseased implants as compared to healthy ones. Thus, it is imperative to identify which factors in the peri-implant micro-environment may reduce Ti corrosion resistance. Methods The aim of this work is to simulate peri-implant inflammatory conditions in vitro to determine which factors affect corrosion susceptibility of Ti-6Al-4V dental implants. The effects of hydrogen peroxide (surrogate for reactive oxygen species, ROS, found during inflammation), albumin (a protein typical of physiological fluids), deaeration (to simulate reduced pO2 conditions during inflammation), in an acidic environment (pH 3), which is typical of inflammation condition, were investigated. Corrosion resistance of Ti-6Al-4V clinically-relevant acid etched surfaces was investigated by electrochemical techniques: Open Circuit Potential; Electrochemical Impedance Spectroscopy; and Anodic Polarization. Results Electrochemical tests confirmed that most aggressive conditions to the Ti-6Al-4V alloy were those typical of occluded cells, i.e. oxidizing conditions (H2O2), in the presence of protein and deaeration of the physiological medium. Conclusions Our results provide evidence that titanium’s corrosion resistance can be reduced by intense inflammatory conditions. This observation indicates that the micro-environment to which the implant is exposed during peri-implant inflammation is highly aggressive and may lead to TiO2 passive layer attack. Further investigation of the effect of these aggressive conditions on titanium dissolution is warranted.

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  • IPEN-DOC 26423

    BENTO, RODRIGO T. ; SILVA, ROGER W.O.; DIAS, LUCAS A.; FERRUS FILHO, ANDRE; PITTA, ANTONIO J.C.. Design, development and application of a real‑time capacitive sensor for automatically measuring liquid level. SN Applied Sciences, v. 1, n. 7, 2019. DOI: 10.1007/s42452-019-0770-3

    Abstract: In the present study a real-time capacitive sensor based on a capacitance step method is designed, developed and applied on measuring the liquid level by immersion. The capacitive sensor consists of two electrodes from copper plated phenolite plates separated by a gap distance and mounted inside a non-conductive storage tank. Water is used as the dielectric material. The analyzed sensor behavior with liquid level variation is semi-linear and obtained in function of the output voltage variation by using proper signal conditioning circuit. For converting the voltage variation into level variation, a parallel R–C circuit is used instead of conventional bridge circuit. Under suitable parameter settings it provided good reading accuracy. The experimental results demonstrate the high efficiency of the proposed model, which confirm the satisfactory performance of the capacitive sensor for liquid level measurement. The sensor presents an excellent ease of construction and installation, linked to the good measurements precision and high autonomy of system operation. The behavior experiments under different salt concentrations show that the water chemical composition does not interfere on the sensor operation. The proposed model exhibits a promising employment in several applications, such as control equipment for irrigation, biomedical area—in the interaction between antibody–antigen or protein-DNA, aerospace and pharmaceutical industry, gas sensors, and automation solutions.

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  • IPEN-DOC 26422

    RODRIGUES, FLAVIO T. ; MARCHIONI, ERIC; LORDEL-MADELEINE, SONIA; KUNTZ, FLORENT; VILLAVICENCIO, ANNA L.C.H. ; JULIEN-DAVID, DIANE. Degradation of profenofos in aqueous solution and in vegetable sample by electron beam radiation. Radiation Physics and Chemistry, v. 166, p. 1-7, 2020. DOI: 10.1016/j.radphyschem.2019.108441

    Abstract: In this study, the role of accelerated electron irradiation on the removal of profenofos in aqueous solution and in peas was investigated. The samples were irradiated with a Rhodotron E-beam accelerator with 10 MeV energy at doses of 0 (control), 4.6, 12 and 32 kGy. Irradiated vegetable samples were extracted using a QuEChERS protocol (quick, easy, cheap, effective, rugged, and safe), allowing analysis of pesticide traces. Quantification of profenofos in aqueous solution was performed by using GC-MS in SIM mode and GC-MS/MS in MRM mode in vegetable sample. Degradation of profenofos increased with the E-beam dose and was much more important in aqueous solution than in vegetable. In irradiated aqueous solution, one degradation product was detected.

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  • IPEN-DOC 26420

    BRANCACCIO, F. ; DIAS, M.S. ; KOSKINAS, M.F. ; MOREIRA, D.S. ; TOLEDO, F. de . Data analysis software package for radionuclide standardization with a digital coincidence counting system. Applied Radiation and Isotopes, v. 155, p. 1-10, 2020. DOI: 10.1016/j.apradiso.2019.108900

    Abstract: The Nuclear Metrology Laboratory (LMN) – IPEN, S~ao Paulo, Brazil – developed a Digital Coincidence System (DCS), based on the Coincidence Counting Methodology, in order to improve its capabilities in radionuclide primary-standardization. Digital process is implemented in two steps: data-acquisition (a set of measurements) and offline software data-analysis and calculation. The present work shows the basics of the data-acquisition unit (Software Coincidence System – SCS), describes the DCS’ data-analysis process and the initial approaches chosen for the implementation of the software package (Coincidence Analyzing Task – CAT). 152Eu standardization, performed for DCS testing, software expansion and validation, is briefly discussed.

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  • IPEN-DOC 26160

    SILVA, PAULO S.C. da ; EL HAJJ, THAMMIRIS M.; DANTAS, G.A.S.A.; TORQUATO, HENRIQUE. Exhalation rates determined in construction material produced from niobium waste. In: ABEN (Ed.) INTERNATIONAL NUCLEAR ATLANTIC CONFERENCE, October 21-25, 2019, Santos, SP. Proceedings... Rio de Janeiro, 2019. p. 556-568.

    Abstract: Mining operations annually generate large volumes of mining waste that can have several environmental impacts requiring appropriate management strategies in the short and long term. Recently, in Brazil, we have witnessed the catastrophic consequences of poor management of these tailings. One way to better manage mining waste may be to reduce its quantity by reusing it. In the case of niobium industry one possibility for the huge amount of solid tailing generated is its application as construction material. Nevertheless, these tailing also carries some radioactive elements. Exposure to radiation originated from construction material is mainly due to the presence of radionuclides from uranium and thorium series. The external exposure comes from the gamma emitters present in the material while internal exposure can come from radon and thoron gas. This study had evaluated the radiological impact of using niobium waste tailing in concrete plates and proof bodies, for use in construction material. It was determined the activity concentration of 238U, 226Ra, 210Pb, 232Th, 228Th, 228Ra and 40K in cement made with niobium waste to compare with commercial cement. Exhalation rates for 222Rn and 220Rn were determined for cement plates and proof bodies made with 0, 50 and 100% of niobium waste. Results showed that the exhalation rates varied from 0.032 ± 0.004 to 0.20 ± 0.01 Bq/m2.s for 222Rn and from 0.044 ± 0.005 to 0.8 ± 0.1 Bq/m2.s for 220Rn in the different cements. The exhalation rate of the plates varied from 0.035 ± 0.002 to 0.35 ± 0.02 Bq/m2.s for 222Rn and from 0.048 ± 0.006 to 1.2 ± 0.1 Bq/m2.s for 220Rn and the variation for the proof bodies was 0.0042 ± 0.0006 to 0.2 ± 0.1 Bq/m2.s and from 0.008 ± 0.001 to 0.054 ± 0.006 Bq/m2.s for 222Rn and 220Rn, respectively.

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  • IPEN-DOC 26159

    SUSSA, FÁBIO V. ; FURLAN, MARCOS R.; VICORINO, MARCOS; SILVA, PAULO S.C. . Soil-to-plant transfer factors for stable elements in lemon balm (Melissa Officinalis L.) commonly used as a medicinal plant. In: ABEN (Ed.) INTERNATIONAL NUCLEAR ATLANTIC CONFERENCE, October 21-25, 2019, Santos, SP. Proceedings... Rio de Janeiro, 2019. p. 545-555.

    Abstract: This study evaluated the transfer factors (TF) of stable elements (essential and non-essential) As, Ba, Br, Ca, Cd, Co, Cr, Cu, Fe, Hf, K, La, Mg, Mn, Na, Ni, Pb, Rb, Sb, Sc, Sm, Th, Ti, V and Zn from soil to Melissa officinalis L. (Lemon balm). The transfer factors were calculated by dividing the metal concentration in Lemon balm leaf by the total metal concentrations in the soil. The experiments were conducted from January 2013 to January 2014 at the Municipal Gardening School area, in Ibirapuera Park, São Paulo, Brazil. The experimental design was completely randomized (CRD), with three treatment: control (site soil), organic (2 t ha-1 poultry manure) and conventional (30 t ha-1 of NPK, 6:14:8), and four harvest (April, July, October and January) with four replications. The soil samples collected (0 – 20 cm) were dried at 100 °C and grounded to 100 mesh size particles and homogenized. Lemon balm samples were collected and washed with ultrapure water to remove impurities and soil particles present in all plant structures, air-dried and the leaves were separated. After these processes, the Lemon balm leaves were dried at 100 °C and grounded to 100 mesh size particles. Instrumental neutron activation analysis (INAA), graphite furnace atomic absorption spectrometry (GFAAS) and inductively coupled plasma optical emission spectrometry (ICP-OES) were applied to determine the elemental concentration in the samples. The results showed that the metals accumulate in species with different intensity. Our findings indicated that Ca, Cd, K, Ni and Rb accumulated the most with the transfer factor of 1.0 – 12, followed by Ba, Br, Co, Cr, Cu, Mg, Mn, Na, Pb, Sb and Zn with TF of 0.1 – 1.0, while As, Fe, Hf, La, Sm, Th, Ti and V had the lowest accumulation with TF usually < 0.1.

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  • IPEN-DOC 26158

    CAVALCANTI, HELOISA S. ; ZAMBONI, CIBELE B. ; MIURA, VIVIANI M. ; AZEVEDO, MARIA R.. The reference value for blood potassium in inhabitants of Brazil by EDXRF technique. In: ABEN (Ed.) INTERNATIONAL NUCLEAR ATLANTIC CONFERENCE, October 21-25, 2019, Santos, SP. Proceedings... Rio de Janeiro, 2019. p. 541-544.

    Abstract: In the present study was intend to use the Energy Dispersive X-Ray Fluorescence technique (EDXRF) to perform potassium dosage in human beings using whole blood aiming its application, in the future, for studying in more details the common deficienciesin Brazilian population helping their diagnostic. To perform this investigation a total of 227 whole blood samples were analyzed. The influence of gender was also investigated. The results provide information which permit to perform a discussion about the advantages and limitations of using this alternative methodology for biochemistry examinations.

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  • IPEN-DOC 26157

    MENEGHINI, ARTHUR A. ; WAKASUGI, DENISE S.M. ; SANTOS, LAISSA A.B. dos ; DAMATTO, SANDRA R. ; SALVADOR, VERA L.R. . Inorganic chemical elements determined in mineral water springs from the water circuit of Minas Gerais, Brazil by X-ray fluorescence spectrometry. In: ABEN (Ed.) INTERNATIONAL NUCLEAR ATLANTIC CONFERENCE, October 21-25, 2019, Santos, SP. Proceedings... Rio de Janeiro, 2019. p. 529-540.

    Abstract: Water Circuit of Minas Gerais (Circuito das Águas de Minas Gerais) is known by its mineral water parks located in the cities of Cambuquira, Caxambu, Conceição do Rio Verde, Lambari and São Lourenço. The mineral water of these parks is consumed regularly by the local population and tourists that are motivated by the medicinal use of the mineral water. One of the characteristics that defines a mineral water is its chemical composition, hence a water is considered mineral due to the chemical elements present in its composition. The objective of this work was to determine the inorganic chemical characterization of the mineral waters from the Water Parks of Cambuquira, Caxambu, Conceição do Rio Verde, Lambari and Marimbeiro analyzing the elements Ag, As, Ba, Ca, Cd, Co, Cr, Cu, Fe, K. Mn, Ni, Pb, Se, Ti, V and Zn by energy dispersive X-ray fluorescence spectrometry – EDXRF. Each water park presented different chemical elements with different concentrations, in spite of the parks are located near each other. The elements that presented the highest concentrations in all the samples analyzed were the major elements Ca, Fe, K and Mn. Among the four water parks studied, the mineral waters from Water Park of Caxambu presented the highest concentrations for all the elements determined. This study is part of a research project developed at CMR that studied the natural radionuclides 226Ra, 228Ra, 210Pb and 210Po and the inorganic chemical elements of the mineral waters of the Water Circuit of Minas Gerais.

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  • IPEN-DOC 26156

    TAPPIZ, BRUNO ; MOREIRA, EDSON G. . Measurement uncertainty evaluation in fish samples analyzed by INAA and AAS. In: ABEN (Ed.) INTERNATIONAL NUCLEAR ATLANTIC CONFERENCE, October 21-25, 2019, Santos, SP. Proceedings... Rio de Janeiro, 2019. p. 521-528.

    Abstract: Measurement uncertainty was estimated following the EURACHEM guide (Quantifying Uncertainty in Analytical Measurement) for the elements As, Br, Cl, Co, Cr, Cs, Fe, K, Mg, Mn, Na, Rb, Sb, Se and Zn determined by Instrumental Neutron Activation Analysis (INAA) and for the elements Cd, Hg and Pb determined by Atomic Absorption Spectrometry (AAS) in the fillet of the most consumed fish species at São Paulo city, Brazil. INAA expanded uncertainties ranged from 1.0 to 21% and the main contributions were due the counting statistics of sample and pipetted standards. For AAS, expanded uncertainties ranged from 6.5 to 13% and the main contributions were associated to the calibration curves. Uncertainty results were compared with the standard deviations of the mass fraction in the fishes (n = 10). Due to the wide variability in the mass fraction in the analyzed fish tissues, explained by factors such gender, age, fat content and fishing location of the specimens of each specie, standard deviations were greater than expanded uncertainties, which means that the natural variability of the elements determined is greater than the data dispersion associate

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  • IPEN-DOC 26155

    JUNQUEIRA, LUCAS S. ; SILVA, SHARLLENY A.; FRANKLIN, ROBSON L.; FAVARO, DEBORAH I.T. . Trace element assessment in sediment cores from Graminha reservoir, São Paulo State, by INAA. In: ABEN (Ed.) INTERNATIONAL NUCLEAR ATLANTIC CONFERENCE, October 21-25, 2019, Santos, SP. Proceedings... Rio de Janeiro, 2019. p. 505-520.

    Abstract: In the present study, sediment cores were collected in the Graminha (Caconde) water supply reservoir in Feb/2015 (points 1 and 3) and Aug/2015 (points 1 and 4) sampling campaigns. The four sediment cores with different depths were cut every 2.5 cm, yielding 36, 21, 33 and 37 slices of sediments, respectively, that were individually analyzed by INAA (Instrumental Neutron Activation Analysis). This analytical technique was used to quantify the elements: As, Ba, Br, Co, Cr, Cs, Fe, Hf, Rb, Sb, Sc, Ta, Zn, U and Th. The validation of precision of the methodolody was made by analyzing certified reference material. The concentration values obtained for As, Cr and Zn were compared with TEL and PEL oriented values established by the CCME (Canada) and adopted by CETESB for sediment quality evaluation. None of the sediment cores analyzed surpassed the PEL value for these elements. Sediment samples from points 2 and 3 presented the worst sediment quality but were still classified as good quality for sediments. The enrichment factor (EF) and Geoacumulation Index (IGeo) tools used for contamination level assessment were used for all sediment cores and mostly presented enrichment on As and U. The results from concentrations, EF and IGeo showed a significant increase mostly below 30 cm of depth in every core. Statistical analyses were applied to the elemental concentration values for better interpretation of the results.

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  • IPEN-DOC 26154

    JUNQUEIRA, LUCAS S. ; ANGELINI, MATHEUS ; ZAHN, GUILHERME S. ; SILVA, PAULO S.C. da . Determination of I-129 on radioactive waste from Angra 1 and 2 Power Plants. In: ABEN (Ed.) INTERNATIONAL NUCLEAR ATLANTIC CONFERENCE, October 21-25, 2019, Santos, SP. Proceedings... Rio de Janeiro, 2019. p. 492-495.

    Abstract: Radioactive waste must be characterized in order to be deposited in a suitable place for its confinement, avoiding any contamination of the environment. This study determined 129I, one of the difficult-to-measure nuclides that make up the radioactive waste from Angra 1 and 2 nuclear power plants. The methodology used a 129-I (1Bq/mL) liquid certified standard and consisted on guarantying that all the iodine was converted into iodide before the addition of PdCl2 for the precipitation of PdI2. After the separation procedure the 129I was quantified by gamma spectrometry by measuring its X-ray emissions with energies of 29.7 keV and 33.8 keV, as well as the gamma-ray emission of 39.6 keV. The chemical yield of the procedure was 74.4% (0,2).

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  • IPEN-DOC 26153

    JUNQUEIRA, LUCAS S. ; ZAHN, GUILHERME S. ; SILVA, PAULO S.C. da . Ni-59 determination by measurement of annihilation energy. In: ABEN (Ed.) INTERNATIONAL NUCLEAR ATLANTIC CONFERENCE, October 21-25, 2019, Santos, SP. Proceedings... Rio de Janeiro, 2019. p. 486-491.

    Abstract: Radioactive waste is subject to regulations regarding its inventory, transportation and final deposition. Such standards require the knowledge of the tailing contents in a way that is possible to accommodate them in a repository capable of containing their radiation completely. In this study a methodology was established for determining the concentration of 59Ni using the annihilation energy (0.511 MeV) between a positron from its + emission, and an electron that is widely present in matter. To ensure the reliability of the methodology, the area of the annihilation peak was compared to 59Ni Kα and Kβ x-ray peaks. To make this method viable the separations of Ni from the other components of the sample was necessary. This was done by using dimethylglyoxime (DMG) for Ni precipitation. Of all the Ni radioisotopes only 59Ni have a half-life longer than a few days, so that 59Ni can be determined without radioisotopical interferences. After precipitation with DMG, the substrate was vacuum filtered on filter paper, using an apparatus to preserve the geometry of the precipitate in different samples. The 59Ni precipitate was then counted in an extended range gamma spectrometer and the 511 keV peak compared to the Ni x-rays in order to verify the reliability of the method.

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  • IPEN-DOC 26152

    LIMA, GEAN B. de ; KAISER, THIAGO J. S.; MOREIRA, EDSON G. . Z-score, a tool for quality assurance of analytical results in neutron activation analysis. In: ABEN (Ed.) INTERNATIONAL NUCLEAR ATLANTIC CONFERENCE, October 21-25, 2019, Santos, SP. Proceedings... Rio de Janeiro, 2019. p. 478-485.

    Abstract: The Nuclear and Energy Research Institute (IPEN CNEN / SP), through the Research Reactor Center (CERPq), conducts several studies using Instrumental Neutron Activation Analysis (INAA) in its Activation Analysis Laboratory (LAN). The present study performed a critical analysis of the way Certified Reference Materials (CRM) are used to assess accuracy in LAN activities, from a statistical point of view. With the wide dissemination and application of metrological concepts, the use of regulatory standards (ABNT and INMETRO) became increasingly necessary. The literature defines several approaches to the statistical principles for the use of the obtained values. CRMs are used to assess the accuracy of analytical methods, being essential for trueness assessment. There are a few ways to quantify trueness, and this can be done by percent relative error and z score, determining the trend of the analytical method, which is defined as the estimation of a systematic error. The use of z scores is interesting in evaluating the quality of analytical methods, as it is less subject to the influence of the concentration value. Theses and dissertations developed at LAN were selected as the object of study and the calculations were performed using the concepts presented to verify the data treatment, at a 95% confidence level, presenting satisfactory results.

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  • IPEN-DOC 26151

    RIBEIRO JR., IBERÊ S. ; GENEZINI, FREDERICO A. ; ZAHN, GUILHERME S. . Comparison of two methodologies for spectra analysis in coincidence neutron activation analysis. In: ABEN (Ed.) INTERNATIONAL NUCLEAR ATLANTIC CONFERENCE, October 21-25, 2019, Santos, SP. Proceedings... Rio de Janeiro, 2019. p. 459-468.

    Abstract: The Research Reactor Center (CERPq) of IPEN-CNEN/SP has been developing a facility for Coincidence Neutron Activation Analysis (CNAA), a variation of the Neutron Activation Analysis technique in which gamma-gamma coincidence is used to reduce spectral interferences and improve detection limits of some elements. As the acquisition results in 2D-coincidence spectra, the spectrum analysis had to be dealt with accordingly. There are two distinct ways to perform these analyses, either directly, by fitting bidimensional peaks in the coincidence matrix, or by gating the spectra in one detector around each peak of interest and fitting the resulting 1D-spectrum in the usual way. In this work the concentrations of As, Co, Cs, Sb and Se were determined in geological and biological reference materials by CNAA using two different methodologies of analysis, using the BIDIM software, which provides 2D-peak-fitting; and a combination of the AnalisaCAEN suite, which gates the 2D-spectra, with Canberra’s Genie2000, which fits the resulting unidimensional spectra. The results allow for a discussion of the advantages and shortcomings of each method, both in terms of usability and of the reliability of the results.

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  • IPEN-DOC 26419

    PRETTO, LUCAS R. de ; MOULT, ERIC M.; ALIBHAI, A.Y.; CARRASCO-ZEVALLOS, OSCAR M.; CHEN, SIYU; LEE, BYUNGKUN; WITKIN, ANDRE J.; BAUMAL, CAROLINE R.; REICHEL, ELIAS; FREITAS, ANDERSON Z. de ; DUKER, JAY S.; WAHEED, NADIA K.; FUJIMOTO, JAMES G.. Controlling for artifacts in widefield optical coherence tomography angiography measurements of non-perfusion area. Scientific Reports, v. 9, p. 1-15, 2019. DOI: 10.1038/s41598-019-43958-1

    Abstract: The recent clinical adoption of optical coherence tomography (OCT) angiography (OCTA) has enabled non-invasive, volumetric visualization of ocular vasculature at micron-scale resolutions. Initially limited to 3 mm × 3 mm and 6 mm × 6 mm fields-of-view (FOV), commercial OCTA systems now offer 12 mm × 12 mm, or larger, imaging fields. While larger FOVs promise a more complete visualization of retinal disease, they also introduce new challenges to the accurate and reliable interpretation of OCTA data. In particular, because of vignetting, wide-field imaging increases occurrence of low-OCT-signal artifacts, which leads to thresholding and/or segmentation artifacts, complicating OCTA analysis. This study presents theoretical and case-based descriptions of the causes and effects of low-OCTsignal artifacts. Through these descriptions, we demonstrate that OCTA data interpretation can be ambiguous if performed without consulting corresponding OCT data. Furthermore, using wide-field non-perfusion analysis in diabetic retinopathy as a model widefield OCTA usage-case, we show how qualitative and quantitative analysis can be confounded by low-OCT-signal artifacts. Based on these results, we suggest methods and best-practices for preventing and managing low-OCT-signal artifacts, thereby reducing errors in OCTA quantitative analysis of non-perfusion and improving reproducibility. These methods promise to be especially important for longitudinal studies detecting progression and response to therapy.

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  • IPEN-DOC 26418

    SIMA, O.; DE VISMES OTT, A.; DIAS, M.S. ; DRYAK, P.; FERREUX, L.; GURAU, D.; HURTADO, S.; JODLOWSKI, P.; KARFOPOULOS, K.; KOSKINAS, M.F. ; LAUBENSTEIN, M.; LEE, Y.K.; LEPY, M.C.; LUCA, A.; MENEZES, M.O. ; MOREIRA, D.S. ; NIKOLIC, J.; PEYRES, V.; SAGANOWSKI, P.; SAVVA, M.I.; SEMMLER, R. ; SOLC, J.; THANH, T.T.; TYMINSKA, K.; TYMINSKI, Z.; VIDMAR, T.; VUKANAC, I.; YUCEL, H.. Consistency test of coincidence-summing calculation methods for extended sources. Applied Radiation and Isotopes, v. 155, p. 1-11, 2020. DOI: 10.1016/j.apradiso.2019.108921

    Abstract: An internal consistency test of the calculation of coincidence-summing correction factors FC for volume sources is presented. The test is based on exact equations relating the values of FC calculated for three ideal measurement configurations. The test is applied to a number of 33 sets of FC values sent by 21 teams. Most sets passed the test, but not the results obtained using the quasi-point source approximation; in the latter case the test qualitatively indicated the magnitude of the bias of FC.

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  • IPEN-DOC 26417

    RIBEIRO, AMON S.L. ; ARATA, ANELYSE ; LIMA, NELSON B. de ; USSUI, VALTER ; LAZAR, DOLORES R.R. . Comparison of a laboratorial scale synthesized and a commercial yttria‐tetragonal zirconia polycrystals ceramics submitted to microwave sintering. International Journal of Applied Ceramic Technology, v. 16, n. 5, SI, p. 2020-2027, 2019. DOI: 10.1111/ijac.13310

    Abstract: Conventional sintering techniques of yttria‐tetragonal zirconia polycrystals (Y‐TZP) ceramics have presented limitations regarding the sintering time and temperature, increasing the cost of the final dental and biomedical products. Herein, microwave sintering comes to be an interesting alternative by providing fast heating, high densification, and grain‐size control. The aim of this study was to compare the effect of microwave sintering of Y‐TZP dental ceramics prepared from a pre‐sintered commercial block and produced from powders synthesized in a laboratorial scale by the precipitation route. The synthetized and commercial discs were submitted to microwave sintering at 1450°C and 1350°C for 15, 30, and 60 minutes. Densification, fracture toughness, grain size, and crystalline phase quantification of the sintered groups were evaluated. Both synthetized and commercial groups sintered at 1450°C for 15 and 30 minutes showed the higher densification results (98% TD). XRD quantitative phase analysis indicates that samples present 89% tetragonal and 11% cubic phases, except for the group prepared from coprecipitated powders sintered at 1450°C for 30 minutes, that presented 79% and 21% of tetragonal and cubic phases. The microwave sintering at 1450°C allows hardness and fracture toughness values comparable to conventional sintering.

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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.