Reposiório IPEN: Recent submissions

  • IPEN-DOC 26460

    URIOSTE, ARIEL; ZAJAC, MARIA A.L.; AQUINO, SIMONE ; RIBEIRO, ANDREZA P.. Logística reversa de explantes cirúrgicos em um hospital filantrópico: implantação de um novo modelo ecoeficiente de gerenciamento de resíduo hospitalar / Reverse logistics of surgical explant in a philanthropic hospital: implementation of a new ecoefficient model of management hospital waste. Revista de Gestão em Sistemas de Saúde, v. 7, n. 3, p. 257-273, 2018. DOI: 10.5585/rgss.v7i3.415

    Abstract: Explantes cirúrgicos são dispositivos metálicos que foram implantados cirurgicamente em pacientes e que depois de retirados seguem uma destinação diferenciada dos demais resíduos hospitalares, já que devem ser submetidos ao processo de esterilização para serem considerados resíduos sem risco biológico. O presente estudo teve como objetivo implantar um sistema de gerenciamento de descarte de explantes cirúrgicos, após um diagnóstico realizado por meio do uso parcial da ferramenta de avaliação o Sistema Contábil Gerencial Ambiental (SICOGEA), considerando as etapas de preparação dos materiais, desde a geração do resíduo até sua disposição final. Para a implantação do sistema de gerenciamento foram aplicadas ferramentas de controle, elaboração de fluxo e capacitação dos funcionários, cujos métodos foram preparados em conjunto com os responsáveis pelas as áreas técnicas envolvidas e, por fim, após o explante ser considerado resíduo inservível é encaminhado a uma empresa especializada no tratamento dos resíduos de explantes para a manufatura reversa. Estudos futuros devem ser realizados para ampliar a análise para outros estabelecimentos de serviços de saúde, bem como realizar uma análise mais aprofundada da ecoeficiência do processo hospitalar. Com as medidas supracitadas implantadas, foi observado que houve um aumento de 45% para 100% da ecoeficiência nas operações relacionadas à destinação de resíduos de explantes, como resultado das melhorias implantadas no gerenciamento de descarte e encaminhamento para manufatura reversa.

    Palavras-Chave: management; surgical materials; manufacturing; reverse-field pinch; residues; accounting; environment; efficiency; sustainability; waste disposal; waste management

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  • IPEN-DOC 26458

    CARVALHO, LEANDRO G. de; PLAUT, RONALD L.; LIMA, NELSON B. de ; PADILHA, ANGELO F.. Kinetics of martensite reversion to austenite during overaging in a maraging 350 steel. ISIJ International, v. 59, n. 6, p. 1119-1127, 2019. DOI: 10.2355/isijinternational.ISIJINT-2018-610

    Abstract: The present work has studied the kinetics of partial reversion of martensite into austenite, which occurred during overaging between 520 and 600°C in a maraging 350 steel. The microstructural modifications were followed using optical microscopy, scanning electron microscopy, X-ray diffraction and ferritoscopy. The observations carried out using microscopy showed that the reverted austenite is formed at interface regions such as grain boundaries, boundaries of the packets and martensite laths boundaries of the martensitic structure starting at 520°C, while the reverted austenite observed inside the martensite lath was formed starting at 560°C. The maximum percentage volumetric fractions of retained austenite were 18%, 25% and 37%, respectively for 520, 560 and 600°C. The higher the aging temperature, the faster the volumetric fraction attained its plateau of maximum constant value. The activation energy for the kinetics of the austenite reversion process has been determined as being 332 kJ/mol. The Avrami constant for the kinetics of the reverted austenite at 520°C was close to 1, while at 560°C was close to 2. The values determined for the activation energy and of the Avrami constants have been discussed and correlated with the possible transformation mechanisms.

    Palavras-Chave: maraging steels; phase transformations; kinetics; austenite; martensite; optical microscopy; scanning electron microscopy; x-ray diffraction

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  • IPEN-DOC 26457

    PIRES, J.A. ; HARDER, M.N.C.; ARTHUR, V.; SILVA, L.C.A.S.. Ionizing radiation effects in Brazilian grape tree wine. Brazilian Journal of Radiation Sciences, v. 7, n. 2A, p. 1-14, 2019. DOI: 10.15392/bjrs.v7i2A.630

    Abstract: The aim of this work was to irradiate brazilian grape tree (Myrciaria cauliflora) wines with gamma radiation (Co60) to investigate the effect of radiation on its components and to create a new product with quality for the superior fermented beverages market. For this wine was produced in an artisan way, but with all the care of hygiene and sanitation. The brazilian grape tree was femented for five days and the wine was then filtered and stored in inert material containers then irradiated at 2.5 and 5 kGy doses. The samples were evaluated in relation to the radiation doses used. Physical and chemical analyzes of pH; total and volatile acidity; alcohol content; anthocyanins; tannins and colorimetry were performed. As a result, in most product analysis, had little effect on irradiation, except for anthocyanins and tannins. For this can be concluded that it is possible to develop a new fermented drink based on brazilian grape tree, according to the standards required by the legislation and that the irradiation at the dose of 5kGy was the sample that shown to have the most effect on the color because it was the one that degraded most molecules of anthocyanins and tannins.

    Palavras-Chave: absorption spectroscopy; alcohols; beverages; chemical analysis; cobalt 60; gamma radiation; grapes; ph value; physical properties; radiation doses; radiation effects; tannic acid; trees

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  • IPEN-DOC 26456

    SILVA, HARYANE R.M.; FAUSTINO, WAGNER M.; TEOTONIO, ERCULES E.S.; BRITO, HERMI F.; MALTA, OSCAR L.; FELINTO, MARIA C.F.C. . Investigation on the formation of highly luminescent β-diketone-Ln(III)-EDTA water-soluble complexes. Journal of Luminescence, v. 207, p. 182-187, 2019. DOI: 10.1016/j.jlumin.2018.10.021

    Abstract: Three new β-diketone–Ln-EDTA (β-diketone=TTA, BTFA, ACAC; Ln=Eu3+ and Tb3+) water-soluble complexes were prepared, and their photophysical properties were investigated in aqueous solutions and compared with the Eu–EDTA complex. A very strong red and green luminescence was observed by the addition of ligands to the aqueous solutions of the Eu–EDTA and Tb–EDTA complexes, respectively, due to the formation of watersoluble β-diketone–Ln–EDTA complexes. To confirm the formation and stoichiometry of the new β- diketone–Ln–EDTA complex, the Judd–Ofelt intensity parameters Ω2 for Eu3+ complexes and the band width at half height (Δλ) for Tb3+ complexes were used. The dependence of these parameters on the addition of the β- diketone strongly suggests that only one β-diketonate ligand is in the first coordination sphere of the β- diketone–Ln–EDTA complexes. These new Eu3+ and Tb3+ systems may act as red and green optical markers for bioassay or bioimaging.

    Palavras-Chave: rare earths; rare earth complexes; luminescence; edta; ketones; photoluminescence; solubility

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  • IPEN-DOC 26455

    FUJIMOTO, TALITA G. ; REIS, SHIRLEY L. ; MUCCILLO, ELIANA N. dos S. . Influence of yttria-stabilized zirconia on microstructure and electrical properties of doped lanthanum gallate. Materials Research, v. 22, S1, p. 1-6, 2019. DOI: 10.1590/1980-5373-MR-2019-0043

    Abstract: Lanthanum gallate with partial substitutions for strontium and magnesium shows higher ionic conductivity than traditional ionic conductors such as yttria-stabilized zirconia (8YSZ), and has been considered for application as solid electrolyte and electrode in Solid Oxide Fuel Cells operating at intermediate temperatures (500-700ºC). Parallel to the development of new solid electrolytes, improvement of the already known electrolytes has been one goal. In this work, the effects of adding 8YSZ to La0.9Sr0.1Ga0.8Mg0.2O3-δ (LSGM), on the microstructure and electrical performance were investigated. Compound electrolytes consisting of up to 20 wt.% 8YSZ were prepared by solid state reactions. Sintered pellets with up to 10 wt.% 8YSZ achieved near full density after sintering at 1450ºC and reduction in the fraction of impurity phases. Addition of 8YSZ promoted grain growth to LSGM. The higher ionic conductivity was obtained for 1 wt.% 8YSZ addition with slight decrease of the apparent activation energy.

    Palavras-Chave: lanthanum; zirconium; microstructure; magnesium; ionic conductivity; solid oxide fuel cells; impedance; electrical properties; electrolytes

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  • IPEN-DOC 26453

    SABINO, CAETANO P.; WAINWRIGHT, MARK; ANJOS, CAROLINA dos; SELLERA, FABIO P.; BAPTISTA, MAURICIO S.; LINCOPAN, NILTON; RIBEIRO, MARTHA S. . Inactivation kinetics and lethal dose analysis of antimicrobial blue light and photodynamic therapy. Photodiagnosis and Photodynamic Therapy, v. 28, p. 186-191, 2019. DOI: 10.1016/j.pdpdt.2019.08.022

    Abstract: Background: Antimicrobial Photodynamic therapy (A-PDT) has been used to treat infections. Currently, microbial inactivation data is reported presenting survival fraction averages and standard errors as discrete points instead of a continuous curve of inactivation kinetics. Standardization of this approach would allow clinical protocols to be introduced globally, instead of the piecemeal situation which currently applies. Methods: To this end, we used a power-law function to fit inactivation kinetics and directly report values of lethal doses (LD) and a tolerance factor (T) that informs if inactivation rate varies along the irradiation procedure. A deduced formula was also tested to predict LD for any given survival fraction value. We analyzed the photoantimicrobial effect caused by red light activation of methylene blue (MB-APDT) and by blue light (BL) activation of endogenous microbial pigments against 5 clinically relevant pathogens. Results: Following MB- APDT, Escherichia coli and Staphylococcus aureus cells become increasingly more tolerant to inactivation along the irradiation process (T < 1). Klebsiella pneumoniae presents opposite behavior, i.e., more inactivation is observed towards the end of the process (T > 1). P. aeruginosa and Candida albicans present constant inactivation rate (T˜1). In contrast, all bacterial species presented similar behavior during inactivation caused by BL, i.e., continuously becoming more sensitive to blue light exposure (T > 1). Conclusion: The power-law function successfully fit all experimental data. Our proposed method precisely predicted LD and T values. We expect that these analytical models may contribute to more standardized methods for comparisons of photodynamic inactivation efficiencies.

    Palavras-Chave: antimicrobial agents; therapy; chemotherapy; inactivation; lethal doses; light sources; data analysis; candida; methylene blue

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  • IPEN-DOC 26452

    GAROFALO, S.A.; SAKAE, L.O.; MACHADO, A.C.; CUNHA, S.R.; ZEZELL, D.M. ; SCARAMUCCI, T.; ARANHA, A.C.. In vitro effect of innovative desensitizing agents on dentin tubule occlusion and erosive wear. Operative Dentistry, v. 44, n. 2, p. 168-177, 2019. DOI: 10.2341/17-284-L

    Abstract: Purpose: The purpose of this study was to evaluate the effects of four in-office desensitizing products on dentin tubule occlusion and erosive wear. Methods: Dentin hypersensitivity was simulated by EDTA application for five minutes. The specimens were randomly allocated into five groups (n=11), according to treatment:No treatment - Control (C), Duraphat (DUR), Desensibilize Nano P (NP), ClinPro XT Varnish (XTV), and ClinPro White Varnish (CWV). They were then submitted to erosive/abrasive cycling for five days. After EDTA, treatment, and cycling, the specimens were analyzed with an environmental scanning electron microscope (ESEM) to verify the number of opened dentin tubules (ODT) which were counted by using ImageJ software, and with a profilometer to determine the surface curvature/loss. ESEM data were analyzed with two-way repeated measure analysis of variance and Tukey tests. For the profilometer, data were analyzed with Kruskal- Wallis, Tukey, and Mann-Whitney tests. Results: After treatment, all groups showed lower ODT than the control, without significant differences between them. After cycling, the only group that showed lower ODT than the control was group XTV; however, it did not significantly differ from the other groups. For the profilometric analysis, there were significant differences in SL between the experimental times after treatment and after cycling for all groups (p,0.05). After cycling, no surface loss was detected in groups DUR and XTV, which presented a significantly different curvature than group NP and the control group, but not from group CWV. Surface loss was detected for the control and groups NP and CWV, without difference among them. Conclusion: All desensitizing agents tested presented promising results concerning the obliteration of dentin tubules immediately after treatment. XTV was the only desensitizer capable of preventing the reopening of the tubules after the erosive/abrasive challenges. XTV and DUR presented a protective effect against dentin erosive wear.

    Palavras-Chave: dentistry; in vitro; tubules; clathrates; environment; scanning electron microscopy; statistical data

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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.

    Palavras-Chave: titanium; niobium; bcc lattices; desorption; absorption; hydrogen; cold working; rolling; hydrogenation; hydrogen storage

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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.

    Palavras-Chave: nanoparticles; synthesis; zirconium; plants; adsorption; sorptive properties; tetracyclines; antibiotics

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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.

    Palavras-Chave: tomography; optical systems; photon computed tomography; coherence length; backscattering; attenuation; coefficient of performance; phantoms

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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.

    Palavras-Chave: proteins; lectins; immunology; cytochemistry; biochemical reaction kinetics; blood cells; hematologic agents; immune reactions

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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.

    Palavras-Chave: calculation methods; comparative evaluations; computerized simulation; dosimetry; monte carlo method; photon beams; planning; proton beams; proton transport; radiation dose distributions; radiotherapy

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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.

    Palavras-Chave: hormones; pituitary gland; lth; kidneys; animal cells; mass spectroscopy; glycoproteins; bioassay

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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.

    Palavras-Chave: ionization; inner-shell ionization; k shell; tellurium; tantalum; bismuth; cross sections; theoretical data; experimental data; data analysis

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  • IPEN-DOC 26405

    FERREIRA, THIAGO dos S.. 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: 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.

    Palavras-Chave: ceramics; silicon nitrides; yttrium alloys; aluminium oxides; oxide minerals; titanium oxides; nitrogen additions; microstructure; materials testing; trace amounts; sintering; hardness; fracture properties; mechanical properties; implants; x-ray diffraction; scanning electron microscopy; dispersion relations

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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 - Implant Esthetic and Reconstructive Dentistry, 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.

    Palavras-Chave: lasers; laser radiation; erbium; prostheses; dentistry; adhesives; fibers; teeth; roots

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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.

    Palavras-Chave: attenuation; cobalt 60; composite materials; gamma radiation; lignin; sintering; tungsten; beta decay radioisotopes; transition elements; years living radioisotopes

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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.

    Palavras-Chave: mineralization; copper; x-ray diffraction; scanning electron microscopy; energy; dispersion relations; spectroscopy; tomography; neutrons; neutron radiography

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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.

    Palavras-Chave: ionic conductivity; bismuth; metals; vanadium oxides; solid electrolytes; ceramics; sintering; impedance; spectroscopy; solid oxide fuel cells

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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.

    Palavras-Chave: electrical properties; sintering; samarium; cerium; doped materials; thermal expansion; dilatometry; impedance; spectroscopy; ceramics; scanning electron microscopy

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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.

    Palavras-Chave: nitrogen; stainless steels; steels; cooling; gas tungsten-arc welding; thermal cycling; microhardness; microstructure

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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.

    Palavras-Chave: argon; ferritic steels; films; kinetics; microstructure; oxidation; oxygen; partial pressure; scanning electron microscopy; stainless steels; temperature range 0400-1000 k; x-ray diffraction

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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: INTERNATIONAL NUCLEAR ATLANTIC CONFERENCE, October 21-25, 2019, Santos, SP. Proceedings... Rio de Janeiro: Associação Brasileira de Energia Nuclear, 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.

    Palavras-Chave: aquifers; concentration ratio; ecological concentration; natural radioactivity; radiation detectors; recommendations; underground; water; who; brazil

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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: INTERNATIONAL NUCLEAR ATLANTIC CONFERENCE, October 21-25, 2019, Santos, SP. Proceedings... Rio de Janeiro: Associação Brasileira de Energia Nuclear, 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.

    Palavras-Chave: aqueous solutions; cyanobacteria; electron beams; irradiation; radiation doses; toxicity; toxins; water

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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: INTERNATIONAL NUCLEAR ATLANTIC CONFERENCE, October 21-25, 2019, Santos, SP. Proceedings... Rio de Janeiro: Associação Brasileira de Energia Nuclear, 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.

    Palavras-Chave: building materials; construction industry; desulfurization; flue gas; gamma spectroscopy; gypsum; natural radioactivity; neutron activation analysis; public health; radiation effects

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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.

    Palavras-Chave: laser spectroscopy; optical systems; amorphous state; rare earths; germanates; doped materials; glass; laser radiation; waveguides

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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: INTERNATIONAL NUCLEAR ATLANTIC CONFERENCE, October 21-25, 2019, Santos, SP. Proceedings... Rio de Janeiro: Associação Brasileira de Energia Nuclear, 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.

    Palavras-Chave: aqueous solutions; drugs; ecological concentration; electron beams; environmental effects; environmental protection; irradiation; toxicity; waste water

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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: INTERNATIONAL NUCLEAR ATLANTIC CONFERENCE, October 21-25, 2019, Santos, SP. Proceedings... Rio de Janeiro: Associação Brasileira de Energia Nuclear, 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.

    Palavras-Chave: elements; gamma spectroscopy; humidity; minerals; sludges; trace amounts; brazil

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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: INTERNATIONAL NUCLEAR ATLANTIC CONFERENCE, October 21-25, 2019, Santos, SP. Proceedings... Rio de Janeiro: Associação Brasileira de Energia Nuclear, 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.

    Palavras-Chave: coke; concentration ratio; elements; neutron activation analysis; nondestructive testing; petroleum; plastics; quantitative chemical analysis; rubbers

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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: INTERNATIONAL NUCLEAR ATLANTIC CONFERENCE, October 21-25, 2019, Santos, SP. Proceedings... Rio de Janeiro: Associação Brasileira de Energia Nuclear, 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.

    Palavras-Chave: diet; elements; food; health hazards; neutron activation analysis; nutrients; toxicity

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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: INTERNATIONAL NUCLEAR ATLANTIC CONFERENCE, October 21-25, 2019, Santos, SP. Proceedings... Rio de Janeiro: Associação Brasileira de Energia Nuclear, 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.

    Palavras-Chave: acid neutralizing capacity; concentration ratio; elements; iear-1 reactor; irradiation; neutron activation analysis; ph value; solids; trace amounts; uranium; water

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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: INTERNATIONAL NUCLEAR ATLANTIC CONFERENCE, October 21-25, 2019, Santos, SP. Proceedings... Rio de Janeiro: Associação Brasileira de Energia Nuclear, 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.

    Palavras-Chave: computer codes; data; data base management; information; information retrieval; information systems; neutron activation analysis; standardized terminology

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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: INTERNATIONAL NUCLEAR ATLANTIC CONFERENCE, October 21-25, 2019, Santos, SP. Proceedings... Rio de Janeiro: Associação Brasileira de Energia Nuclear, 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.

    Palavras-Chave: fuel elements; high-purity ge detectors; iear-1 reactor; radiochemical analysis; radioisotopes; radiometric analysis; time dependence; water

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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: INTERNATIONAL NUCLEAR ATLANTIC CONFERENCE, October 21-25, 2019, Santos, SP. Proceedings... Rio de Janeiro: Associação Brasileira de Energia Nuclear, 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.

    Palavras-Chave: comparative evaluations; gamma spectroscopy; geology; isotope ratio; neutron activation analysis; potassium 40; radioactivity; sediments; thorium 232; uranium 238

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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.

    Palavras-Chave: rocks; granites; ionization; ionizing radiations; computerized simulation; natural radioactivity; dosimetry; monte carlo method; phantoms; radioisotopes; uranium 238; thorium 232; potassium 40; brazil

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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.

    Palavras-Chave: methane; fuel cells; methanol; spectroscopy; electrocatalysts; catalysts; natural gas; raman spectroscopy; transmission electron microscopy

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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.

    Palavras-Chave: compton effect; computer codes; efficiency; high-purity ge detectors; iear-1 reactor; neutron activation analyzers; programming languages; spectra; brazilian cnen; ge semiconductor detectors

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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.

    Palavras-Chave: pmma; luminescence; scanning electron microscopy; synthesis; emission spectra; europium complexes; rare earth complexes; doped materials

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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.

    Palavras-Chave: accuracy; cadmium; corrections; iear-1 reactor; indium 113 target; iridium 191 target; irradiation; neutron activation analysis; neutron spectra; selenium 74 target; tungsten 186 target; brazilian cnen

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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.

    Palavras-Chave: americium 241; bonner sphere spectrometers; brazilian cnen; calibration; neutron detectors; neutron sources; radiation scattering analysis; shadow effect

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  • IPEN-DOC 26424

    BERBEL, LARISSA O. ; BANCZEK, EVERSON do P.; KAROUSSIS, 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

    Observação: Correction anexado. PLoS ONE, v. 14, n. 5, 2019. DOI: 10.1371/journal.pone.0217671

    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.

    Palavras-Chave: titanium alloys; implants; dentistry; corrosion protection; inflammation; infectious diseases; oral cavity; corrosion resistant alloys; electrochemistry; corrosion products

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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.

    Palavras-Chave: sensors; real time systems; capacitance; liquids; level indicators; measuring methods; capacitors; voltmeters

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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.

    Palavras-Chave: insecticides; pesticides; electron beams; mass spectroscopy; decontamination; chemical composition; irradiation; neutrons; ionization; electron beams

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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.

    Palavras-Chave: control systems; computer codes; standardization; radionuclide metrology; coincidence methods; data analysis; counting techniques; brazilian cnen

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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: INTERNATIONAL NUCLEAR ATLANTIC CONFERENCE, October 21-25, 2019, Santos, SP. Proceedings... Rio de Janeiro: Associação Brasileira de Energia Nuclear, 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.

    Palavras-Chave: breath; building materials; cements; construction; dose rates; exhalation; gamma spectroscopy; neutron activation analysis; niobium; public health; radon; statistical data; thorium

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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: INTERNATIONAL NUCLEAR ATLANTIC CONFERENCE, October 21-25, 2019, Santos, SP. Proceedings... Rio de Janeiro: Associação Brasileira de Energia Nuclear, 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.

    Palavras-Chave: absorption spectroscopy; concentration ratio; ecological concentration; elements; medicinal plants; neutron activation analysis; public lands; recreational areas; brazil

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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: INTERNATIONAL NUCLEAR ATLANTIC CONFERENCE, October 21-25, 2019, Santos, SP. Proceedings... Rio de Janeiro: Associação Brasileira de Energia Nuclear, 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.

    Palavras-Chave: biochemistry; blood; brazil; doses; human populations; potassium; x-ray fluorescence analysis; x-ray spectroscopy

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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: INTERNATIONAL NUCLEAR ATLANTIC CONFERENCE, October 21-25, 2019, Santos, SP. Proceedings... Rio de Janeiro: Associação Brasileira de Energia Nuclear, 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.

    Palavras-Chave: drinking water; elements; environment; fluorescence spectroscopy; public lands; recreational areas; water springs; x-ray fluorescence analysis; brazil

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  • IPEN-DOC 26156

    TAPPIZ, BRUNO ; MOREIRA, EDSON G. . Measurement uncertainty evaluation in fish samples analyzed by INAA and AAS. In: INTERNATIONAL NUCLEAR ATLANTIC CONFERENCE, October 21-25, 2019, Santos, SP. Proceedings... Rio de Janeiro: Associação Brasileira de Energia Nuclear, 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

    Palavras-Chave: absorption spectroscopy; brazil; data covariances; elements; evaluation; fishes; neutron activation analysis; toxicity

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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: INTERNATIONAL NUCLEAR ATLANTIC CONFERENCE, October 21-25, 2019, Santos, SP. Proceedings... Rio de Janeiro: Associação Brasileira de Energia Nuclear, 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.

    Palavras-Chave: elements; evaluation; metals; neutron activation analysis; sampling; sediments; trace amounts; water reservoirs; brazil

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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: INTERNATIONAL NUCLEAR ATLANTIC CONFERENCE, October 21-25, 2019, Santos, SP. Proceedings... Rio de Janeiro: Associação Brasileira de Energia Nuclear, 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).

    Palavras-Chave: activity meters; energy spectra; gamma spectroscopy; iodides; iodine 129; nuclear power plants; radioactive wastes; x-ray emission analysis

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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: INTERNATIONAL NUCLEAR ATLANTIC CONFERENCE, October 21-25, 2019, Santos, SP. Proceedings... Rio de Janeiro: Associação Brasileira de Energia Nuclear, 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.

    Palavras-Chave: annihilation; comparative evaluations; dimethylglyoxime; gamma spectrometers; nickel 59; radioactive wastes; reliability; sampling

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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: INTERNATIONAL NUCLEAR ATLANTIC CONFERENCE, October 21-25, 2019, Santos, SP. Proceedings... Rio de Janeiro: Associação Brasileira de Energia Nuclear, 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.

    Palavras-Chave: accuracy; calibration standards; data; data analysis; neutron activation analysis; quality assurance; statistical data; statistical models

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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: INTERNATIONAL NUCLEAR ATLANTIC CONFERENCE, October 21-25, 2019, Santos, SP. Proceedings... Rio de Janeiro: Associação Brasileira de Energia Nuclear, 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.

    Palavras-Chave: biological materials; calibration standards; comparative evaluations; concentration ratio; geology; neutron activation analysis; spectra

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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.

    Palavras-Chave: ophthalmology; retina; biomedical radiography; tomography; vascular diseases; optical equipment; coherent radiation; images; blood vessels; beam scanners

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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.

    Palavras-Chave: gasers; gamma radiation; spectroscopy; coincidence methods; corrections; gamma spectroscopy; high-purity ge detectors; radiation detectors; monte carlo method

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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.

    Palavras-Chave: sintering; ceramics; polycrystals; yttrium oxides; zirconium oxides; tetragonal lattices; microwave radiation; mechanical properties; microstructure; dentistry; teeth; biological materials

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  • IPEN-DOC 26415

    ZAHN, GUILHERME S. ; JUNQUEIRA, LUCAS S. ; GENEZINI, FREDERICO A. . CAX and Xsel: a software bundle to aid in automating NAA spectrum analysis. Brazilian Journal of Radiation Sciences, v. 7, n. 2A, p. 1-7, 2019. DOI: 10.15392/bjrs.v7i2A.565

    Abstract: In this work, the scripting capabilities of Genie-2000 were used to develop a software (CAX) that automatically anal-yses all spectrum files in either ORTEC's CHN or CANBERRA's MCA or CNF formats in a folder, generating two output files: a print-ready text file (.DAT) and a Comma-Separated Values (.CSV) file which can be easily imported in any major spreadsheet software. A second tool, named Xsel, consists in an EXCEL spreadsheet which automatically identifies the spectrum lines associated with the elements of interest, generating a clean output sheet which can be easily imported in a general spreadsheet that calculates the concentrations; an important addition to this spreadsheet is the ability to automatically recalibrate each spectrum, increasing the reliability of the peak identification procedure. These software tools are already used in daily routines at IPEN's Neutron Activation Laboratory, greatly reducing the time required for sample analyses, as well as reducing the possibility of transcription errors.

    Palavras-Chave: automation; neutron activation analysis; gamma radiation; gamma spectra; computer codes; calibration; performance; brazilian cnen; data processing

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  • IPEN-DOC 26414

    SCAGLIUSI, SANDRA R. ; CARDOSO, ELIZABETH C.L. ; ESPER, FABIO ; LUGAO, ADEMAR B. . Butyl rubber recycling via gamma radiation followed by mechanical shear. Ecology, Pollution and Environmental science: Open Access (EEO), v. 1, n. 4, p. 84-88, 2018.

    Abstract: Polymeric materials (plastics and rubber) have been contributing in a continuously and raising way for the generation of litter and industrial wastes discarded in landfills. The implementation of new technologies for the reduction of polymeric materials, acceptable from the environmental viewpoint and at an effective cost, proved to be a great problem, due to complexities inherent for the re-use, especially of rubbers. Gamma ionizing radiation has capacity for changing structure and properties of polymeric materials and can be applied to almost all types of polymers; irradiation is an expectation for problem-solving of rubber wastes management that can be utilized as raw-materials or chemical additives. The relatively low degree of unsaturation presented by butyl rubber (IIR) is responsible for the great resistance of butyl rubber to oxygen, ozone and heat, as well as low gas and water vapor permeability. At the initial stage of irradiation, the degradation of bromobutyl rubber occurs predominantly via random chain-scission and chain-crosslinking may occur caused from the isoprene copolymerized units. This work aims to the introduction of a new recovery technique for bromobutyl rubber, by using processing via gamma rays followed by shear. Rubber was irradiated at 0 kGy, 5 kGy, 15 kGy, 25 kGy, 50 kGy, 100 KGy, 150 kGy and 200 KGy doses, in order to study the feasibility of bromobutyl rubber for recycling. 25 kGy doses, applied to butyl rubber further sheared, pointed toward a less degraded material, indicating that this type of elastomer is able to be incorporated to a new rubber compound and replacing some parts of pristine rubber in formulations without imparting great losses in physical-chemical properties.

    Palavras-Chave: rubbers; recycling; gamma radiation; ionizing radiations; environmental protection; shear; mechanical properties; tensile properties

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  • IPEN-DOC 26413

    COELHO, GUILHERME R.; PREZOTTO NETO, PEDRO ; BARBOSA, FERNANDA C.; SANTOS, RAFAEL S. dos; BRIGATTE, PATRICIA; SPENCER, PATRICK J. ; SAMPAIO, SANDRA C.; D’AMELIO, FERNANDA; PIMENTA, DANIEL C.; SCIANI, JULIANA M.. Biochemical and biological characterization of the Hypanus americanus mucus: a perspective on stingray immunity and toxins. Fish and Shellfish Immunology, v. 93, p. 832-840, 2019. DOI: 10.1016/j.fsi.2019.08.049

    Abstract: Stingrays skin secretions are largely studied due to the human envenoming medical relevance of the sting puncture that evolves to inflammatory events, including necrosis. Such toxic effects can be correlated to the biochemical composition of the sting mucus, according to the literature. Fish skin plays important biological roles, such as the control of the osmotic pressure gradient, protection against mechanical forces and microorganism infections. The mucus, on the other hand, is a rich and complex fluid, acting on swimming, nutrition and the innate immune system. The elasmobranch's epidermis is a tissue composed mainly by mucus secretory cells, and marine stingrays have already been described to present secretory glands spread throughout the body. Little is known about the biochemical composition of the stingray mucus, but recent studies have corroborated the importance of mucus in the envenomation process. Aiming to assess the mucus composition, a new noninvasive mucus collection method was developed that focused on peptides and proteins, and biological assays were performed to analyze the toxic and immune activities of the Hypanus americanus mucus. Pathophysiological characterization showed the presence of peptidases on the mucus, as well as the induction of edema and leukocyte recruitment in mice. The fractionated mucus improved phagocytosis on macrophages and showed antimicrobial activity against T. rubrumç. neoformans and C. albicans in vitro. The proteomic analyses showed the presence of immune-related proteins like actin, histones, hemoglobin, and ribosomal proteins. This protein pattern is similar to those reported for other fish mucus and stingray venoms. This is the first report depicting the Hypanus stingray mucus composition, highlighting its biochemical composition and importance for the stingray immune system and the possible role on the envenomation process.

    Palavras-Chave: fishes; skin; secretion; animal tissues; hazardous materials; venoms; proteins; biochemistry; antimicrobial agents; biological materials; immune reactions; immunity

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  • IPEN-DOC 26410

    OTTONI, CRISTIANE A.; SIMÕES, MARTA F.; SANTOS, JONAS G.; PEIXOTO, LUCIANA; MARTINS, CLEITON R.; SILVA, BRUNO P.; NETO, ALMIR O. ; BRITO, ANTONIO G.; MAIORANO, ALFREDO E.. Application of microbial fuel cell technology for vinasse treatment and bioelectricity generation. Biotechnology Letters, v. 41, n. 1, p. 107-114, 2019. DOI: 10.1007/s10529-018-2624-2

    Abstract: Objective Our study evaluated the performance of different two-chambered microbial fuel cell (MFC) prototypes, operated with variable distance between electrodes and Nafion membrane and specific inoculum concentration, applied for vinasse treatment. Results The performance of the developed MFC resulted in a maximum current density of 1200 mA m-2 and power density of 800 mW m-2 in a period of 61 days. MFC performed a chemical oxygen demand removal at a rate ranging from 51 to 60%. Conclusions Taking our preliminary results into consideration, we concluded that the MFC technology presents itself as highly promising for the treatment of vinasse.

    Palavras-Chave: fuel cells; biofuels; biological materials; ethanol; biomass; bioethanol; bioelectricity; chemical oxygen demand; energy sources

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  • IPEN-DOC 26409

    IZIDORO, JULIANA ; CASTANHO, DAVI ; ROSSATI, CARLOS ; FUNGARO, DENISE ; GUILHEN, SABINE ; NOGUEIRA, THIAGO; ANDRADE, MARIA de F.. Application of high-purity zeolite a synthesized from different coal combustion by-products in carbon dioxide capture. International Journal of Environmental Impacts, v. 2, n. 3, p. 215-228, 2019. DOI: 10.2495/EI-V2-N3-215-228

    Abstract: High-purity zeolites A were synthesized from different coal combustion by-products (baghouse filter fly ash, cyclone filter ash, and bottom ash) and characterized in terms of morphology, chemical, and mineralogical composition. The products were tested for carbon dioxide capture by using a continuous CO2 flow system passing through a column packed with the adsorbent material, which was connected to an analyser that directly measures the concentration of CO2. The values of CO2 adsorption capacities calculated for the unmodified Na-A zeolites (ZABF, ZACF, and ZABA) were 556.48, 494.29 and 654.82 mg g–1, respectively. These values were higher than those achieved by the calcium-modified zeolite samples. ZABA adsorbent presented the best performance in CO2 capture when compared to the other adsorbent material and achieved an adsorption capacity 32% higher than a 4A commercial zeolite. In the adsorption cycles study, the percentage of CO2 desorption by ZABA at the second and third cycles reached 93%, showing that zeolite A can be regenerated by heating at 150 ºC. The use of coal ashes to obtain zeolites and the application of these products for the CO2 adsorption can be an important strategy to mitigate both the problem of waste management and the greenhouse gases emission in coal-fired power plants.

    Palavras-Chave: zeolites; carbon dioxide; coal; combustion; ashes; combustion products; adsorbents; waste management

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  • IPEN-DOC 26406

    GUILHEN, SABINE N. ; COTRIM, MARYCEL E.B. ; SAKATA, SOLANGE K. ; SCAPIN, MARCOS A. . Application of the fundamental parameter method to the assessment of major and trace elements in soil and sediments from Osamu Utsumi uranium mine by WDXRF. REM - International Engineering Journal, v. 72, n. 4, p. 609-617, 2019. DOI: 10.1590/0370-44672018720146

    Abstract: Wavelength dispersive X-ray fluorescence spectrometry (WDXRF) is a suitable technique for the characterization of contaminated mining sites, providing a quick and reliable screening for areas of significant contamination. This study established and validated a non-destructive methodology for quantitative simultaneous determination of major and minor constituents in soil and sediments by WDXRF, which was further applied to quantify soil and sediment samples from Osamu Utsumi uranium mine (Caldas, Minas Gerais, Brazil). Elements such as Ce, La, Nd, Mn and U were found in more concentrated levels in the calcium diuranate deposit (DUCA), whereas Fe and Al were found at higher levels in the soil samples corresponding to sites where accentuated leaching processes have occurred. Comparatively, the levels of U and rare-earth elements were found in significantly higher levels in the sediments retrieved from the mine’s pit as a result of acid mine drainage. These findings are believed to be useful as an initial environmental assessment for the decommissioning process of the mine.

    Palavras-Chave: uranium mines; wavelengths; x-ray fluorescence analysis; x-ray spectroscopy; fluorescence spectroscopy; calculation methods; validation; soils; sediments; brazil; environmental impacts

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  • IPEN-DOC 26404

    MOREIRA, GREGORI de A. ; LOPES, FABIO J. da S. ; GUERRERO-RASCADO, JUAN L.; SILVA, JONATAN J. da ; GOMES, ANTONIO A. ; LANDULFO, EDUARDO ; ALADOS-ARBOLEDAS, LUCAS. Analyzing the atmospheric boundary layer using high-order moments obtained from multiwavelength lidar data: impact of wavelength choice. Atmospheric Measurement Techniques, v. 12, n. 8, p. 4261-4276, 2019. DOI: 10.5194/amt-12-4261-2019

    Abstract: The lowest region of the troposphere is a turbulent layer known as the atmospheric boundary layer (ABL) and characterized by high daily variability due to the influence of surface forcings. This is the reason why detecting systems with high spatial and temporal resolution, such as lidar, have been widely applied for researching this region. In this paper, we present a comparative analysis on the use of lidar-backscattered signals at three wavelengths (355, 532 and 1064 nm) to study the ABL by investigating the highorder moments, which give us information about the ABL height (derived by the variance method), aerosol layer movement (skewness) and mixing conditions (kurtosis) at several heights. Previous studies have shown that the 1064 nm wavelength, due to the predominance of particle signature in the total backscattered atmospheric signal and practically null presence of molecular signal (which can represent noise in high-order moments), provides an appropriate description of the turbulence field, and thus in this study it was considered a reference. We analyze two case studies that show us that the backscattered signal at 355 nm, even after applying some corrections, has a limited applicability for turbulence studies using the proposed methodology due to the strong contribution of the molecular signature to the total backscatter signal. This increases the noise associated with the high-order profiles and, consequently, generates misinformation. On the other hand, the information on the turbulence field derived from the backscattered signal at 532 nm is similar to that obtained at 1064 nm due to the appropriate attenuation of the noise, generated by molecular component of backscattered signal by the application of the corrections proposed.

    Palavras-Chave: troposphere; optical radar; boundary layers; atmospheres; aerosols; turbulence; air quality; monitoring

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  • IPEN-DOC 26403

    OLIVEIRA, ALINE M. de; SOUZA, CRISTINA T.; OLIVEIRA, NARA P.M. de; MELO, ALINE K.S.; LOPES, FABIO J.S. ; LANDULFO, EDUARDO ; ELBERN, HENDRIK; HOELZEMANN, JUDITH J.. Analysis of atmospheric aerosol optical properties in the northeast Brazilian atmosphere with remote sensing data from MODIS and CALIOP/CALIPSO satellites, AERONET photometers and a ground-based Lidar. Atmosphere, v. 10, n. 10, p. 1-22, 2019. DOI: 10.3390/atmos10100594

    Abstract: A 12-year analysis, from 2005 to 2016, of atmospheric aerosol optical properties focusing for the first time on Northeast Brazil (NEB) was performed based on four di erent remote sensing datasets: the Moderate Resolution Imaging Spectroradiometer (MODIS), the Aerosol Robotic Network (AERONET), the Cloud-Aerosol LIDAR with Orthogonal Polarization (CALIOP) and a ground-based Lidar from Natal. We evaluated and identified distinct aerosol types, considering Aerosol Optical Depth (AOD) and Angström Exponent (AE). All analyses show that over the NEB, a low aerosol scenario prevails, while there are two distinct seasons of more elevated AOD that occur every year, from August to October and January to March. According to MODIS, AOD values ranges from 0.04 to 0.52 over the region with a mean of 0.20 and occasionally isolated outliers of up to 1.21. Aerosol types were identified as sea spray, biomass burning, and dust aerosols mostly transported from tropical Africa. Three case studies on days with elevated AOD were performed. All cases identified the same aerosol types and modeled HYSPLIT backward trajectories confirmed their source-dependent origins. This analysis is motivated by the implementation of an atmospheric chemistry model with an advanced data assimilation system that will use the observational database over NEB with the model to overcome high uncertainties in the model results induced by still unvalidated emission inventories.

    Palavras-Chave: aerosols; aerosol monitoring; optical radar; dusts; datasets; satellites; atmospherics; meteorology; optical properties; brazil; atmospheric circulation

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  • IPEN-DOC 26402

    RIOS, D.A.S. ; RIOS, P.B.; SORDI, G.M.A.A. ; CARNEIRO, J.C.G.G. . Análise de situações de exposição potencial em aceleradores de elétrons autoblindados. Brazilian Journal of Radiation Sciences, v. 7, n. 3, p. 1-15, 2019. DOI: 10.15392/bjrs.v7i3.851

    Abstract: Neste estudo foram estimadas as doses decorrentes de situações de exposição potencial em uma indústria de embalagens que utiliza um acelerador de elétrons autoblindado para a cura de tintas e vernizes em substratos poliméricos. Para isso foram avaliadas as probabilidades de falhas no sistema de segurança do acelerador e realizadas simulações envolvendo duas situações acidentais que poderiam levar à exposição potencial de Indivíduos Ocupacionalmente Expostos e Indivíduos do Público. Embora estas situações de exposição sejam pouco prováveis e envolva um número pequeno de indivíduos o estudo ressalta a importância de realizar exercícios de simulação permitindo identificar as possíveis falhas de operação e as consequências radiológicas para esse tipo de evento. Os exercícios de simulação realizados apontaram a necessidade de incluir a equipe de intervenção para saneamento do acidente, representada pela brigada de incêndio a qual foi incluída nos treinamentos periódicos de proteção radiológica. Além disso, as estimativas de falha no sistema de segurança e as doses resultantes demonstraram a conformidade aos requisitos de proteção radiológica.

    Palavras-Chave: accelerators; accidents; failures; occupational exposure; probabilistic estimation; radiation protection; safety analysis; self-shielding; simulation

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  • IPEN-DOC 26401

    FERRARI, MARCELLO ; NEVES, MAURICIO D.M. das ; PANÃO, JULIANO N.. Análise das propriedades mecânicas de juntas de aço carbono estrutural soldadas pelo processo arco submerso com os arcos simples e duplo (Tandem-Arc) / Mechanical properties assessment of structural carbon steel welded joints by means of submerged arc welding process with single arc and double arc (Tandem-Arc). Soldagem & Inspeção, v. 24, p. 1-11, 2019. DOI: 10.1590/0104-9224/SI2304.07

    Abstract: Diante de um cenário econômico onde a concorrência é cada vez mais acirrada, a busca por processos, técnicas e equipamentos de soldagem que proporcionem ganhos na produtividade é uma exigência para garantir a competitividade das empresas no mercado. Com o desenvolvimento e a adoção de novas tecnologias é possível inovar os processos convencionais, otimizando o desempenho e aumentando a produtividade dos mesmos, sem detrimento dos requisitos de qualidade exigidos. O processo de soldagem arco submerso permite a obtenção de juntas soldadas de excelente qualidade e produtividade e, com a utilização de múltiplos arames, é possível aumentar ainda mais a taxa de deposição. Entretanto, o emprego de múltiplos arames implica na necessidade de maiores correntes e, mesmo com o aumento da velocidade de soldagem, o aporte de calor sofre um acréscimo considerável, o que pode afetar a tenacidade da junta. Assim, em estruturas soldadas onde há requisitos de impacto torna-se necessário avaliar os efeitos dos altos aportes de calor. Neste trabalho foi comparada a tenacidade de duas juntas soldadas em aço carbono ASTM A36 pelo processo arco submerso, sendo a primeira soldada com arco simples e a outra com arco duplo (Tandem-Arc). Após a soldagem, as peças de testes foram submetidas ao tratamento térmico de alívio de tensões (TTAT) e submetidas aos ensaios de tração, dobramento, impacto Charpy, perfil de dureza Vickers, exame macrográfico e caracterização microestrutural realizada por meio de microscopia óptica. Os resultados obtidos em todos os ensaios foram considerados satisfatórios e aprovados, mostrando assim que é possível o emprego do processo Tandem-Arc na soldagem de aços carbono quando há requisitos de impacto.

    Palavras-Chave: mechanical properties; carbon steels; arc welding; submerged arc welding; tandem electrostatic accelerators; fracture properties; optical microscopy; charpy test; chemical composition; microstructure

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  • IPEN-DOC 26400

    ZANI, MARINA R.; BIANCHI, PAULO H. ; ARENA, RAQUEL. Análise do comportamento aplicada às organizações: A Gestão do Comportamento Organizacional (Organizacional Behavior Management – OBM) aplicado: desafios e oportunidades na atualidade. Boletim Paradigma, v. 13, p. 7-12, 2018.

    Palavras-Chave: management; behavior; organizational models; employment; working conditions; feedback; performance

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  • IPEN-DOC 26399

    ROVANI, SUZIMARA ; SANTOS, JONNATAN J.; CORIO, PAOLA; FUNGARO, DENISE A. . An alternative and simple method for the preparation of bare silica nanoparticles using sugarcane waste ash, an abundant and despised residue in the Brazilian industry. Journal of the Brazilian Chemical Society, v. 30, n. 7, p. 1524-1533, 2019. DOI: 10.21577/0103-5053.20190049

    Abstract: Sugarcane waste ash, a Si-rich waste product, is generated in large quantities and creates a serious disposal problem in the Brazilian ethanol-sugar industry, affecting the environment and public health. Here, a simple method capable of generating bare silica nanoparticles utilizing this residue is demonstrated. Firstly, the crystalline silica present in sugarcane waste ash (SWA) was converted into amorphous by melting a mixture of sodium hydroxide and SWA at 550 °C for 1 h. The silica nanoparticles (SiO2NPs) were formed by lowing pH. This production process of SiO2NPs from SWA was optimized varying the ash:NaOH mass ratio, increasing the silica extraction up to 96%. The sample’s composition was characterized by total X-ray fluorescence spectroscopy, morphology and physical-chemical properties were investigated by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction, specific surface area measurements, Fourier-transform infrared spectroscopy (FTIR) and thermogravimetric analyses (TGA), followed by use as adsorbent for the removal of methylene blue dye. With this process of extraction, nanoparticles smaller than 100 nm were generated, with a surface area of 63 m2 g-1 and a maximum adsorption capacity of 37 mg g-1 for methylene blue. The results indicate a successful process for obtaining an adsorbent from an industrial waste product using a cost effective and rapid synthesis procedure rendering renewable product.

    Palavras-Chave: sugar cane; wastes; adsorbents; silica; nanoparticles; ethanol fuels; ashes; sodium hydroxides; agriculture; agricultural wastes

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  • IPEN-DOC 26398

    PAPAI, RODRIGO; FREITAS, MILLENA A.S. de; FONSECA, KARINA T. da; ALMEIDA, GILMAR A. de ; SILVEIRA, JOÃO R.F. da; SILVA, ANDRE L.N. da; FERREIRA NETO, JOÃO B.; SANTOS, CELIA A.L. dos; LANDGRAF, FERNANDO J.G.; LUZ, MACIEL S.. Additivity of optical emissions applied to neodymium and praseodymium quantification in metallic didymium and (Nd,Pr)-Fe-B alloy samples by low-resolution atomic emission spectrometry: an evaluation of the mathematical approach used to solve spectral interferences. Analytica Chimica Acta, v. 1085, p. 21-28, 2019. DOI: 10.1016/j.aca.2019.07.049

    Abstract: In this work, the effectiveness of a mathematical approach to solve the spectral interferences involved in the optical emission of two chemical species (neodymium and praseodymium) when using monochromators with low-resolution in atomic spectrometry is evaluated. Although recent technological advances have promoted spectrometers equipped with high-resolution monochromators, which have a great instrumental capability in the separation of nearby lines and consequently avoid spectral interferences, many laboratories still have old spectrometers installed with insufficient resolution to overcome such interferences. In order to evaluate a mathematical approach based on Lambert-Beer's Law, the optical emissions of neodymium and praseodymium were monitored on a low-resolution (200 pm) flame atomic emission spectrometry (F-AES). These two elements were strategically chosen as an application model because they exhibit similar physicochemical properties, joint occurrence in nature and because they are increasingly used in the manufacture of super-magnets, a material increasingly required by the high technology industry. The effectiveness of the mathematical approach was evaluated in three different ways: (i) by recovery of the analytes in synthetic mixtures containing known quantities of the species; (ii) by spike and recovery trials on a representative blend of dissolved samples and (iii) by comparing the results obtained with another analytical method: Inductively coupled plasma optical emission spectrometry (ICP-OES) with a higher spectral resolution. The results indicate the effectiveness of this simple mathematical approach, allow the “survival” of instruments equipped with low-resolution monochromators and demonstrate the applicability of this approach to spectral correction. In addition, this work contributes an analytical method for the quantification of neodymium and praseodymium in metallic alloy samples involved in the production of super-magnets, aiding in the strict quality control of these materials.

    Palavras-Chave: additives; emission; absorption spectroscopy; neodymium; praseodymium; spectra; interference; atoms

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  • IPEN-DOC 26397

    QUEIROZ, CARLA M.S. ; MACHADO, ARTHUR P. ; PAIVA, ANA R.N. ; ANTONIASSI, RODOLFO M. ; VAZ, JORGE M. ; SPINACE, ESTEVAM V. . Active Pt/CeO2 catalysts prepared by an alcohol‑reduction process for low‑temperature CO‑PROX reaction. Materials for Renewable and Sustainable Energy, v. 8, n. 3, p. 1-8, 2019. DOI: 10.1007/s40243-019-0155-y

    Abstract: Pt/CeO2 catalysts were prepared with 0.5 and 1 wt% of Pt loadings by an alcohol-reduction process using a solution of ethylene glycol and water as a reducing agent and solvent. The obtained catalysts were characterized by energy-dispersive X-ray spectroscopy, X-ray diffraction, and transmission electron microscopy. Transmission electron micrographs showed Pt nanoparticles with average sizes of 2.2 and 2.4 nm for Pt content of 0.5 and 1 wt%, respectively. The preferential oxidation of carbon monoxide in hydrogen-rich stream (CO-PROX reaction) was studied in the temperature range of 25–150 °C. Pt/CeO2 catalysts showed maximum CO conversions in the range of 80–98% and CO2 selectivity in the range of 50–70% at 50 °C.

    Palavras-Chave: catalysts; cerium; cerium oxides; platinum; alcohols; reduction; hydrogen; carbon monoxide; selective catalytic reduction

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  • IPEN-DOC 26396

    LINO, JULIANA dos S. ; AQUINO, AFONSO R. de . A study of contaminated land in São Paulo city, Brazil and mainly adopted remediation process face a deficient database. International Journal of Environmental Pollution and Remediation, v. 7, p. 23-35, 2019. DOI: 10.11159/ijepr.2019.003

    Abstract: Since emblematic environment contaminated cases, as Love Canal in United States was found out, the discussion regarding contaminated land are common in scientific community, covering subjects as urban planning, public health and availability of natural resources. Concerns with environment contamination are also relevance because can impact the progress to The Sustainable Development Goals, a global blueprint to develop a sustainable future. Contaminated land refers to areas that have been contaminated by industrial activities, irregular waste disposal or toxic substances. Lack of management of these areas can harm the development of sustainable future, for the cities and citizens. Therefore, the existence and availability of data on the areas that are contaminated is necessary to create better urban planning. In Brazil there are not federal programs to deal with contaminated sites and a federal database regarding this information is absent. However, São Paulo State has been a pioneer in management of contaminated areas in Brazil, developing laws and regulations, since 1999. The aim of this research is to present data regarding contaminated areas in municipality of São Paulo, in five districts, providing information about the scattering of contaminated areas across the districts, the main polluting activity, also observing aspects as revitalization and clean-up process to realize if the remediation process is occurring in the city. This study is a qualitative exploratory research, with information obtained from secondary sources. The results indicated that the main polluting activity is gas station, the process of revitalization and clean-up is happening in all districts evaluated, also showed that environment compartment more affected is Groundwater.

    Palavras-Chave: sustainable development; pollution; land pollution; brownfield sites; urban areas; data analysis; ground water; brazil; environmental impacts; public policy

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  • IPEN-DOC 26395

    REDÍGOLO, MARCELO M. ; ALVES, MARCOS V.R. ; COSTA, ISOLDA ; BUSTILLOS, OSCAR V. . A multi-analytical study of Brazilian commercial acrylic paint of artistic use. International Journal of Conservation Science, v. 10, n. 3, p. 405-414, 2019.

    Abstract: Contemporary Brazilian artists worked massively with paints made in Brazil. Conservation of acrylic paints is an issue and has been studied for the past two decades. European and North American paints were studied in detail, but there is scarce information on paints produced in other countries. Therefore, it is vital to characterize Brazilian artist paint and better understand their ageing process, outlining proper conservation methodologies then. Complementary analytical techniques were employed to characterize the paint samples, namely pyrolysis gas chromatography-mass spectrometry (Py-GC/MS), Fourier transform infrared (FTIR) and Raman spectroscopies and scanning electron microscopy-energy dispersive X-ray spectroscopy (SEM-EDS). Results indicate that Brazilian acrylic blue paints (phthalocyanine and Prussian) are composed of polystyrene (PS) copolymers, in contrast to imported paints, mainly composed of poly(metyhl methacrylate) (PMMA) copolymers.

    Palavras-Chave: paints; pmma; gas chromatography; mass spectroscopy; copolymers; fourier transformation; raman spectroscopy; phthalocyanines; ferrocyanides; brazil; cultural objects; x-ray spectroscopy

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  • IPEN-DOC 26394

    SCURO, N.L. ; UMBEHAUN, P.E. ; ANGELO, E.; ANGELO, G. ; ANDRADE, D.A. . A CFD analysis of blockage length on a partially blocked fuel rod. Brazilian Journal of Radiation Sciences, v. 7, n. 2B, p. 1-20, 2019. DOI: 10.15392/bjrs.v7i2B.437

    Abstract: After a loss of coolant accident (LOCA), fuel rods may balloon. The swelling can partially block the flow channel, affecting the coolability during reflood phase. In order to analyze the influence of blockage length, using a radial block-age of 90%, varying just the blockage length, many steady state numerical simulations has been done using Ansys-CFX code to verify thermal-hydraulic properties according to different forced cooled conditions. Temperature peaks are observed on cladding, followed by a temperature drop. A 5x5 fuel assembly, with 9 centered ballooned fuel rod, flow redistribution inside channels can also be captured, indicating an overheating zone. Therefore, this study conclude, for the same boundary conditions, the longer the blockage length originated after LOCA events, the higher are the clad temperatures, indicating the possibility of overheat during transient conditions on reflood.

    Palavras-Chave: boundary conditions; computerized simulation; flow blockage; fluid mechanics; fuel rods; heat transfer; loss of coolant; numerical analysis; steady-state conditions; turbulence

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  • IPEN-DOC 26393

    FERREIRA, EDUARDO G.A. ; MARUMO, JULIO T. ; FRANCO, MARGARETH K.K.D. ; YOKAICHIYA, FABIANO; VICENTE, ROBERTO . 10000 years cement: Can hydrated cement last as much as long-lived radionuclides?. Cement and Concrete Composites, v. 103, p. 339-352, 2019. DOI: 10.1016/j.cemconcomp.2019.05.016

    Abstract: This review is focused on the long-term performance of cementitious materials in a repository for radioactive waste. During the last few years, the disposal of disused sealed radioactive sources (DSRS) in a borehole type repository has been studied by many countries. The borehole concept is particularly useful to dispose of spent nuclear fuel and DSRS. In boreholes for DSRS, cementitious materials are intended to be used as structural material, immobilization matrix and as backfill. The understanding of the performance of these materials is essential to ensure the safety of the facilities during their required lifetime, from centuries to many thousands of years, depending on the initial activity and half-life of the waste. This review approaches the behavior of the cement from the hydration and hardening to the long-term processes that can affect its durability. Three main causes of failure of repository-engineered barriers are recognized: a) the formation of a preferential pathway for the migration of the contained radionuclides to the biosphere; b) loss of resistance and cohesion of the structural cementitious material; and c) the increase in the corrosion processes of the metallic components of the structures that affect the overall containment of the facility.

    Palavras-Chave: cement industry; portland cement; radioactive wastes; geologic formations; underground disposal; performance; chemical composition; mineralogy; radiations; magnetic fields; hydration

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  • IPEN-DOC 26150

    OLIVEIRA, J.P. ; SILVA, P.S.C. ; SEMMLER, R. . Calibration of the short irradiation facility for K0 − NAA implementation at the IEA-R1 Reactor. In: INTERNATIONAL NUCLEAR ATLANTIC CONFERENCE, October 21-25, 2019, Santos, SP. Proceedings... Rio de Janeiro: Associação Brasileira de Energia Nuclear, 2019. p. 454-458.

    Abstract: The short irradiation facility of the IEA-R1 nuclear research reactor at IPEN, S~ao Paulo, Brazil, has been used for short irradiation of samples for the purpose of determining the concentration of elements of these samples through the use of the instrumental neutron activation analysis technique. With the aim of implementing the k0-NAA method at the Neutron Activation Analysis Laboratory (LAN), the reactor parameters and f were obtained using the bare triple method. In this method, a set of three neutron ux monitors were irradiated without Cd-cover. The e ciency curve of the gamma-ray spectrometer used were determined by measuring calibrated radioactive sources at the usually utilized counting geometries. The results obtained for the parameters and f were respectively 0:0384 0:0016 and 35:67 0:26. The obtained value of f shows that the neutrons in the irradiation position are well thermalized, in other words, the value of f, means that thermal neutron ux is 35 times higher than epithermal neutron ux. It means that this irradiation position is well thermalized. The variation of these parameters was studied with time and the reproducibility was veri ed.

    Palavras-Chave: calibration; cobalt 60; high-purity ge detectors; iear-1 reactor; irradiation; neutron activation analysis; neutron flux

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  • IPEN-DOC 26149

    ANGELINI, MATHEUS ; SILVA, PAULO S.C. da ; JUNQUEIRA, LUCAS S. . Activity determination of the difficult to measure radionuclide 55Fe in operational radioative waste from the Angra Nuclear Power Plant. In: INTERNATIONAL NUCLEAR ATLANTIC CONFERENCE, October 21-25, 2019, Santos, SP. Proceedings... Rio de Janeiro, 2019. p. 446-453.

    Abstract: Pressurized Water Reactors, PWR, are responsible for converting nuclear energy from the nuclear reactions, in the core, into thermal energy by heat exchange with the water in the primary system and then into mechanical energy by the pressure increase from the heat exchange and at last, electrical energy, from the turbine rotation due to the resultant pressure. In a reactor such as described, cool water must flow through the Primary System (where the nuclear core is located) in order to allow heat exchange for electrical energy generation and also to refrigerate the core, providing it will not to be melted or causing any acci dent. Materials that make up the internal part of the primary system such as the walls or core coating may suffer effects like drag force due to the high water pressure or neutron activation due to the high l evels of radiation. Therefore some of these nucl ides that compose these materials are expected to be present in the core water and so, a filtration system is required to reduce these nuclides concentrations. At Angra Nuclear Power Plant two types of filtration systems are used , ion exchange resin, respo nsible for adsorbing these nuclides and a polymer type filter responsible for withholding solid particles in suspension. After a while, these filters become saturated and must b e replaced; once replaced , the old ones become Radioactive Waste of Low or Medi um Activity. This study has evaluated the chemical yield of different procedures for 55 Fe determination by using anion exchange chromatography, to be further applied to determine the activity concentration in nuclear waste samples. The activity concentrati ons were determined by Liquid Scintillation Counting (LSC) and Gamma Spectrometry (GS). This project is part of a bigger objective that aims to fulfill several regulations from the Brazilian National Nuclear Energy Commission (CNEN) and the development of a repository for proper storage of radioactive waste materials

    Palavras-Chave: activity levels; activity meters; ion exchange chromatography; iron 55; nuclear power plants; pwr type reactors; radioactive wastes

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  • IPEN-DOC 26148

    SILVA, CAIO A.J. da ; COSTA, ISOLDA ; ROSSI, JESUALDO L. ; SAIKI, MITIKO . Determination of chemical elements in magnesium- based materials by neutron activation analysis. In: INTERNATIONAL NUCLEAR ATLANTIC CONFERENCE, October 21-25, 2019, Santos, SP. Proceedings... Rio de Janeiro: Associação Brasileira de Energia Nuclear, 2019. p. 427-437.

    Abstract: Over the last decades there was an increasing interest in using magnesium alloys for medical applications due to their biodegradability in the human body, providing a temporary mechanical support and corroding completely after the tissue healing. Although magnesium is a non-toxic element, it is of great importance to evaluate the element concentration, as well as the impurities present in both, pure magnesium and magnesium alloys, as the AZ31. The purpose of this study was to analyze the element composition of these materials using the method of neutron activation analysis (NAA). Standard Reference Materials (SRMs) acquired from National Institute of Standards and Technology (NIST) were analyzed for analytical quality control. Short and long term irradiations were carried out at the IEA-R1 nuclear research reactor and gamma-ray activities induced to the samples and element standard were measured using HPGe detector coupled to a Digital Spectrum Analyzer. The radioisotopes were identified by gamma ray energies and half-life. Concentrations of the elements As, Cr, Cd, Co, Fe, In, La, Mg, Mn, Mo, Na, Sb, V, W and Zn were determined in pure magnesium sample and the Al, As, La, Mg, Mn, Na, Sb and Zn in the AZ31 alloy, calculated by comparative method. The SRMs were analyzed by applying the same experimental conditions used for magnesium-based materials and their results presented good accuracy and precision. Thus, from the measurements obtained in this study it can be concluded that NAA is a suitable method for element determinations in magnesium-based materials providing reliable results.

    Palavras-Chave: biological materials; chemical analysis; iear-1 reactor; irradiation; magnesium alloys; medicine; neutron activation analysis; prostheses

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  • IPEN-DOC 26147

    BRAGUIN, LILIAN N.M. ; COSTA, ISOLDA ; SAIKI, MITIKO . Elemental determination of austenitic stainless steel alloy used as biomaterial by neutron activation analysis. In: INTERNATIONAL NUCLEAR ATLANTIC CONFERENCE, October 21-25, 2019, Santos, SP. Proceedings... Rio de Janeiro: Associação Brasileira de Energia Nuclear, 2019. p. 416-426.

    Abstract: Austenitic stainless steel alloys, mainly those produced according to ISO 5832-1, have received much attention due to their promising characteristics to be used as biomaterials. The aim of this study was to establish the proper conditions of neutron activation analysis (NAA) in order to determine chemical elements in a sample of ISO 5832-1 stainless steel. These determinations are of great interest for further evaluation of its corrosion resistance and of cytotoxicity of corrosion products. For the analyses, chips of ISO 5832-1 austenitic stainless steel were obtained. Aliquots of this material were weighed in polyethylene involucres and irradiated together with synthetic element standards at the IEA-R1 nuclear research reactor. Short and long irradiations were carried out using thermal neutron flux of about 4.5 x 1012 n cm-2 s -1. Quality control of the results was performed by analyzing two certified reference materials (CRMs). The elements concentrations of Cr, Cu, Mn, Mo and Ni obtained in the ISO 5832-1 austenitic alloy are within the specification values of this material. Besides, the elements As, Co, V and W were determined in this alloy. The sensitivity of the technique was verified by the determination of detection and quantification limits. In the case of CRMs, their results presented precision and accuracy for most of elements with relative standard deviations and relative errors lower than 15 %. Results obtained in this study demonstrated the viability of applying NAA in the analysis of the ISO 5832-1 stainless steel alloy.

    Palavras-Chave: alloys; austenitic steels; biological materials; calibration standards; iear-1 reactor; irradiation; neutron activation analysis; prostheses; stainless steels

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  • IPEN-DOC 26146

    MEDEIROS, ILCA M.M.A. ; ZAMBONI, CIBELE B. ; GIOVANNI, DALTON N.S. ; MEDEIROS, JOSÉ A.G. de. Investigation of elements in sweeteners by NAA analytic technique. In: INTERNATIONAL NUCLEAR ATLANTIC CONFERENCE, October 21-25, 2019, Santos, SP. Proceedings... Rio de Janeiro: Associação Brasileira de Energia Nuclear, 2019. p. 402-407.

    Abstract: In this study, brands of sweeteners (aspartame and sucralose) marketed in Brazil were investigated by Neutron Activation Analysis (NAA). The measurements were performed using the IEA-R1 nuclear reactor at IPEN - CNEN/SP. The elements Cl and Na were identified in all samples. The Na concentration in sweeteners samples showed low content for most of the brands (0.013 –3.81 g kg-1), while Cl had high concentration variation (0.04 – 11.10 g kg-1). These data provide knowledge regarding nutritional aspect and toxicity derived from sweetener consumption.

    Palavras-Chave: chlorine; iear-1 reactor; irradiation; neutron activation analysis; nutrition; saccharose; sodium

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  • IPEN-DOC 26145

    ZAMBONI, CIBELE B. ; METAIRON, SABRINA ; MEDEIROS, JOSE A.G. de ; SILVA, DALTON G.N. da ; TASSO, ORION G. . Progress and trends for radiation applications in clinical practice. In: INTERNATIONAL NUCLEAR ATLANTIC CONFERENCE, October 21-25, 2019, Santos, SP. Proceedings... Rio de Janeiro: Associação Brasileira de Energia Nuclear, 2019. p. 396-401.

    Abstract: In this study, we intend to optimize the use of equipment based on the X-Ray Fluorescence technology to perform ions dosage in body fluids. This procedure can be an efficient alternative for clinical diagnosis, mainly in underserved regions of Brazil with the deficit of medical care in the hospitals. In addition, this procedure has potential use when the biological material is scarce, case of the pediatric practice in newborns and premature infants (blood collection is the main cause of transfusions) as well as in Hemodialysis units which requires several biochemical tests (before and after dialysis).

    Palavras-Chave: biological materials; blood; body fluids; diagnostic uses; experimental data; neutron activation analysis; numerical data; x radiation; x-ray spectrometers

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  • IPEN-DOC 26144

    CHAMAS, CLAUDIA ; MOREIRA, EDSON G. ; MENEZES, MARIO O. de . Data governance for neutron activation analysis. In: INTERNATIONAL NUCLEAR ATLANTIC CONFERENCE, October 21-25, 2019, Santos, SP. Proceedings... Rio de Janeiro: Associação Brasileira de Energia Nuclear, 2019. p. 383-395.

    Abstract: This study describes the importance of managing scientific research data, and incorporating the demands that are currently presented such as data sharing, data repositories, metadata management, as well as ensuring the truth and value of data. A proper data management helps in gaining insight on data governance. The area of study is the Nuclear and Energy Research Institute (IPEN – CNEN/SP) where there is a wide variety of researches, yielding lots of data. IPEN has already recognized the importance of proper management of research data as an essential part of the research's good practices and of the institution's commitment to the truthfulness and quality of its scientific research. Following this commitment, IPEN has established the necessity of data management and sharing in order to ensure the greatest possible benefits for scientific and technological advancement. A case study with data from neutron activation analysis experiments, belonging to the Neutron Activation Analysis Laboratory (LANCERPq) of IPEN is presented. The current status of data management was assessed and a basic implementation plan for a proper data management was proposed, delineating also a path to the adoption of data governance practices at a larger scale in the whole IPEN-CNEN/SP.

    Palavras-Chave: data; data processing; information dissemination; management; neutron activation analysis; planning; technology transfer

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  • IPEN-DOC 26143

    CORREIA, RUANYTO W. ; ROSTELATO, MARIA E.C.M. ; ZEITUNI, CARLOS A. . Study and calibration of the HPGe detector for radionuclide analysis of iodine-125. In: INTERNATIONAL NUCLEAR ATLANTIC CONFERENCE, October 21-25, 2019, Santos, SP. Proceedings... Rio de Janeiro: Associação Brasileira de Energia Nuclear, 2019. p. 370-382.

    Abstract: In this work, a theoretical-experimental methodology was developed for the calibration of HPGe Detector for quantitative analysis of iodine-125. Photopick efficiencies was measured between 0 - 40 keV using a certified calibration source (iodine-129) with well-known activity. The efficiency curve was determined for an energy range that covers the region of interest for iodine-125 (0 - 40 keV). The calibrate spectrum was obtained for study and the result was saved in the detector directory for future analysis and determination of the iodine-125 activity.

    Palavras-Chave: calibration; computer codes; high-purity ge detectors; iodine 125; quantitative chemical analysis

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  • IPEN-DOC 26142

    MANTOVANI, JULIANA ; SCAPIN, MARCOS A. ; MACACCINI, JOSÉ. F.; COTRIM, MARYCEL E.B. ; PIRES, MARIA A.F. . Applying multi-incremental sampling methodology to soils for radiological and environmental risks evaluation. In: INTERNATIONAL NUCLEAR ATLANTIC CONFERENCE, October 21-25, 2019, Santos, SP. Proceedings... Rio de Janeiro: Associação Brasileira de Energia Nuclear, 2019. p. 362-369.

    Abstract: Multi-increment soil sampling is a methodology that allows evaluating environmental liability inside decision unit, providing a representative aliquot for laboratory analysis with associated uncertainties lower than conventional sampling. The literature has reported much works about environmental liabilities evaluation in soil using multi-increment sampling however, for nuclear facilities soils are practically nonexistent. Therefore, aim of this study was to determinate radionuclides concentration (by Gamma spectroscopy), major and minor constituents (by X-ray fluorescence spectrometry) and metals (by Inductively Coupled Plasma-Atomic Emission Spectrometry) in soils of nuclear material storage facilities in Nuclear and Energy Research Institute (IPEN/CNEN-SP) using multi-increment sampling. The natural radionuclides (210Pb, 226Ra, 228Ra, 238U), major and minor constituents (MgO, Al2O3, SiO2, P2O5, K2O, CaO, TiO2, and others) and metals (Cr, Fe, Co, Ni, Zn, As, Pb, and other) were determined in 120 soil samples, in-depth between 0 and 150 mm at 30 quadrants. The results showed specific activity of 57 ± 16 Bq kg-1 (210Pb), 51 ± 22 Bq kg-1 (226Ra), 81 ± 12 Bq kg-1 (228Ra) and 48 ± 14 Bq kg-1 (238U), corresponding uncontaminated soil, according reference values. With regarding metals concentration, results also were lower than values reference. The statistical tests showed that methodology is efficient for environmental impact studies and monitoring programs and adequate to attend established conditions in IPEN-CNEN / SP environmental licensing.

    Palavras-Chave: elements; environmental impacts; gamma spectroscopy; metals; nuclear materials management; radioisotopes; sampling; soils; trace amounts; x-ray fluorescence analysis

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  • IPEN-DOC 26111

    UMBELINO, U.; PIRES, K.C.C.; LICHTENTHALER, R.; SCARDUELLI, V.; SCOTTON, G.A.; LEPINE-SZILY, A.; GUIMARÃES, V.; LUBIAN, J.; PAES, B.; FERREIRA, J.L.; ALVAREZ, M.A.G.; SHORTO, J.M.B. ; APPANNABABU, S.; ASSUNÇÃO, M.; CONDORI, R.P.; MORCELLE, V.. Two-neutron transfer in 7Be + 9Be collisions. Physical Review C, v. 99, n. 6, p. 064617-1 - 064617-13, 2019. DOI: 10.1103/PhysRevC.99.064617

    Abstract: Elastic scattering and transfer cross sections for the 7Be + 9Be system have been measured at Elab = 23.1 MeV using the 7Be radioactive secondary beam produced at Radioactive Ion Beams in Brazil facility at the University of São Paulo. The elastic scattering has been measured by detecting the 7Be scattered at forward angles in the laboratory system. The transfer reaction 9Be(7Be, 9Be)7Be was identified by detecting the 9Be scattered at the same laboratory angles. The elastic angular distribution has been analyzed by optical model calculations using a Woods-Saxon form factor whose parameters have been varied to best reproduce the experimental data at forward angles. Coupled reaction channels calculations (CRC) have been performed to describe the transfer, considering the coupling to the transfer channel and including contributions to the ground state and to the first excited state of 7Be(1/2−; 429 keV) in the final state. The spectroscopic amplitudes used in the CRC calculation have been derived from shell-model calculations. Similar CRC calculations were applied to existing 9Be(p, t )7Be data to check the consistency of our results results for the (7Be, 9Be) transfer reaction.

    Palavras-Chave: beryllium 7; beryllium 9; elastic scattering; coupled channel theory; ion beams; neutrons; neutron beams; neutron transfer

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  • IPEN-DOC 26109

    COSTA, ISRAEL F.; MOURA, JANDEILSON L.; ADERNE, RIAN E.; AVILA, HAROLD C.; CREMONA, MARCO; BRITO, HERMI F.; FELINTO, MARIA C.F.C. ; FAUSTINO, WAGNER M.; TEOTONIO, ERCULES E.S.. Tuning emitting color of electroluminescent devices containing tris(2‑acyl‑1,3‑indandionate)aluminum(III) complexes as emitting layers. Journal of the Brazilian Chemical Society, v. 30, n. 8, p. 1647-1656, 2019. DOI: 10.21577/0103-5053.20190064

    Abstract: In this study, a novel type of tris(2-acyl-1,3-indandione)-aluminum(III) coordination compounds of the general formula [Al(acind)3]H2O, where 2-acyl-1,3-indandione (acind), 2-acetyl- 1,3-indandione (aind), 2-benzoyl-1,3-indandione (bind), and 4-methyl-2-benzoyl-1,3-indandione (mbind), were synthesized and characterized by elemental analysis (CHN), Fourier transform infrared (FTIR) and nuclear magnetic resonance (1H NMR) spectroscopies, thermal analysis (TG/DTG and DTA), and optical absorption spectroscopy in the UV-Vis region. These compounds present remarkably high green luminescence in powder and in thin-film forms. However, when these compounds are applied in glass/ITO/β-NPB/spiro-2CBP/[Al(acind)3]/Al and glass/ITO/β‑NPB/ [Al(acind)3]/LiF/Al electroluminescent devices, where spiro-2CBP is 2,7-bis(carbazol-9-yl)-9,9- spirobifluorene and β-NPB is N,N’-bis(naphthalen-2‑yl)-N,N’-bis(phenyl)-benzidine, the emission color tuned from green to red, reflecting a change from the direct charge recombination in the emitting layer of the [Al(acind)3] complexes to an exciplex-based emission in which [Al(acind)3] complexes and spiro 2-CBP acted as acceptor and donor, respectively. These results suggest that [Al(acind)3] complexes have potential applications as molecular light converter materials for fabricating new electroluminescent devices.

    Palavras-Chave: electroluminescence; light emitting diodes; tuning; fourier transformation; infrared spectra; aluminium complexes; wavelengths

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  • IPEN-DOC 26141

    COTIS, DÉBORA S.; MARQUES, LEILA S.; FIGUEIREDO, ANA M.G. ; CORVAL, ARTUR; VALENTE, SÉRGIO C.. Application of neutron activation analysis to the study of low-titanium tholeiitic dykes of the Serra do Mar Swarm (RJ). In: INTERNATIONAL NUCLEAR ATLANTIC CONFERENCE, October 21-25, 2019, Santos, SP. Proceedings... Rio de Janeiro: Associação Brasileira de Energia Nuclear, 2019. p. 330-343.

    Abstract: The tholeiitic dykes of the Serra do Mar Swarm (SMS) outcrop along the coast of the São Paulo and Rio de Janeiro states (Southeastern Brazil), spreading over the Rio Paraiba Valley. Previous studies carried out in such dykes showed that they are related to the tectonic and magmatic processes that took place during the South Atlantic Ocean opening and gave rise to the Paraná Magmatic Province (PMP). The dykes are vertical to subvertical and preferentially NE-SW trending, with thicknesses ranging from centimeters to tens of meters. Most of the SMS intrusive rocks have relatively high concentrations of TiO2 (>3wt%), except for occurrences in the Região dos Lagos (Costa Azul Suite), as well as around Nova Friburgo Town (Serrana Suite), where they are characterized by basic rocks with low TiO2 (<2wt%) contents, whose genesis are still not completely understood. Therefore, a detailed study is being carried out in rocks of the Suite Serrana, with the determination of the concentrations of the rare earth (REE: La, Ce, Nd, Sm, Eu, Tb, Yb, and Lu) and other trace (Ta, Th, U, Hf, Cs, Sc, and Co) elements by instrumental neutron (thermal and epithermal) activation analysis, which has accuracy and precision required for petrogenetic studies. The data obtained so far show a substantial enrichment of highly incompatible trace elements (light REE, Th and U) and a remarkable geochemical similarity with the low-TiO2 basaltic flows of Gramado type found in southern PMP, suggesting important processes of crustal contamination during the genesis of the investigated dykes.

    Palavras-Chave: elements; geology; igneous rocks; neutron activation analysis; radioisotopes; titanium; trace amounts; brazil

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  • IPEN-DOC 26140

    NOGUEIRA, ANDRÉ L.; MUNITA, CASIMIRO S. . The effect of data standardization in cluster analysis. In: INTERNATIONAL NUCLEAR ATLANTIC CONFERENCE, October 21-25, 2019, Santos, SP. Proceedings... Rio de Janeiro: Associação Brasileira de Energia Nuclear, 2019. p. 321-329.

    Abstract: The application of multivariate techniques to experimental results requires a responsibility on behalf of the researcher to understand, evaluate and interpret their results, especially the ones that are more complex. In this work, the impact of three standardization techniques on the formation of clusters by the SOM (self-organizing map) neural network were studied. The techniques studied were logarithm (log10), generalized-log and improved min-max. The studies were performed using two databases consisting of 298 and 146 samples and containing the mass fractions of As, Na, K, La, Yb, Lu, U, Sc, Cr, Fe, Cs, Eu, Tn, Hf and Th, determined by neutron activation analysis. The results were evaluated using validation indices.

    Palavras-Chave: algorithms; cluster analysis; computer codes; data; mass; neural networks; neutron activation analysis; standardization; statistical models

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  • IPEN-DOC 25565

    SERRA, PEDRO L.S.; MASOTTI, PAULO H.F. ; ROCHA, MARCELO S. ; ANDRADE, DELVONEI A. de ; TORRES, WALMIR M. ; MESQUITA, ROBERTO N. de . Two-phase flow void fraction estimation based on bubble image segmentation using Randomized Hough Transform with Neural Network (RHTN). Progress in Nuclear Energy, v. 118, p. 1-21, 2020. DOI: 10.1016/j.pnucene.2019.103133

    Abstract: The International Atomic Energy Agency (IAEA) has been encouraging the use of passive cooling systems in new designs of nuclear power plants. Next nuclear reactor generations are intended to have simpler and robust safety resources. Natural Circulation based systems hold an undoubtedly prominent position among these. The study of limiting conditions of these systems has led to instability behavior analysis where many different two-phase flow patterns are present. Void fraction is a key parameter in thermal transfer analysis of these flow instability conditions. This work presents a new method to estimate void fraction from images captured of an experimental two-phase flow circuit. The method integrates a set of Artificial Neural Networks with a modified Randomized Hough Transform to make multiple scans over acquired images, using crescent-sized masks. This method was called Randomized Hough Transform with Neural Network (RHTN). Each different mask size is chosen according with bubble sizes, which are the main ‘objects of interest’ in this image analysis. Images are segmented using fuzzy inference with different parameters adjusted based on acquisition focus. Void fraction calculation considers the volume of the imaged geometrical section of flow inside cylindrical glass tubes considering the acquisition depth-of-field used. The bubble volume is estimated based on geometrical parameters inferred for each detected bubble. The image database is obtained from experiments performed on a vertical two-phase flow circuit made of cylindrical glass where flow-patterns visualization is possible. The results have shown that the estimation method had good agreement with increasing void fraction experimental values. RHTN has been very efficient as bubble detector with very low ‘false-positive’ cases (< 0.004%) due robustness obtained through integration between Artificial Neural Networks with Randomized Hough Transforms.

    Palavras-Chave: two-phase flow; void fraction; neural networks; image processing; bubbles; fuzzy logic; transformations; nuclear power plants; pattern recognition; natural convection; randomness

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  • IPEN-DOC 26139

    GUILHEN, SABINE N. ; SOUZA, ALEXANDRE L.; COTRIM, MARYCEL E.B. ; PIRES, MARIA A.F. . Direct determination of aluminum in low-enriched UALx targets ( UAlx-Al) by inductively coupled plasma optical emission spectrometry. In: INTERNATIONAL NUCLEAR ATLANTIC CONFERENCE, October 21-25, 2019, Santos, SP. Proceedings... Rio de Janeiro: Associação Brasileira de Energia Nuclear, 2019. p. 298-311.

    Abstract: The production of molybdenum-99 (99Mo) using low-enriched uranium targets (< 20% 235U) dispersed in aluminum (UAlx) is a very promising strategy towards the independence in 99Mo local production. A thorough control must be performed to ensure that these targets meet the regulatory requirements to achieve the expected efficiency in the reactor. The determination of the targets’ composition is of high interest, because the distribution of Al in different phases may have an impact on the U concentration. Among the techniques used for this purpose, inductively coupled plasma optical emission spectrometry (ICP OES) stands out because of its high sensitivity and precision, allowing for simultaneous determination of several elements in a variety of samples and matrices. However, because U exhibits a complex emission spectrum, spectral interferences are prone to affect the analysis of Al, calling for time consuming preparation steps to remove the U from the matrix. This study proposes a method of direct determination of Al in UAlx targets through the selection of specific emission lines enabled by the evaluation of the associated interferences on the recovery values.

    Palavras-Chave: aluminium; chemical analysis; emission spectroscopy; molybdenum 99; plasma; technetium 99; uranium 235 target

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  • IPEN-DOC 23928

    FERREIRA, MERILYN S. ; WETTER, NIKLAUS U. . Yb:KGW self-Raman laser with 89 cm(−1) Stokes shift and more than 32% diode-to-Stokes optical efficiency. Optics and Laser Technology, v. 121, p. 1-4, 2020. DOI: 10.1016/j.optlastec.2019.105835

    Abstract: We report on a Yb3+:KGW self-Raman laser operating at 1096 nm. A 100 μm fiber-coupled diode end-pumped configuration is used to generate a fundamental emission wavelength that strongly depends on internal resonator losses. Stokes emission at 1096 nm is achieved with a slope efficiency of 42 ± 8%, an optical conversion efficiency of more than 32% and a maximum output power of 4.5W for quasi-continuous operation (1 ms pulses). The explored Stokes conversion of 89 cm−1 shows excellent laser characteristics, indicating that this still little explored Stokes shift could pave the way to continuous-wave Raman frequency-comb lasers.

    Palavras-Chave: lasers; raman effect; doped materials; solid state lasers; raman spectra; stokes parameters; wavelengths; crystals

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  • IPEN-DOC 26138

    RODRIGUES JR ., ORLANDO ; SANTOS, SILAS C. dos . Stability study of the alanine epr dosimetry system at IPEN/CNEN SP. In: INTERNATIONAL NUCLEAR ATLANTIC CONFERENCE, October 21-25, 2019, Santos, SP. Proceedings... Rio de Janeiro: Associação Brasileira de Energia Nuclear, 2019. p. 259-264.

    Abstract: The dosimetry system using alanine EPR is a standard secondary calibration system for high doses. IPEN's High Doses Dosimetry Laboratory (LDA) has an Electron Paramagnetic Resonance equipment operating in the X band which performs high dose dosimetry service for electron and X ray fields for the dose range of 10Gy to 200kGy. IPEN has established a dosimetry system based on an alanine dosimeter developed at the institute. The system is composed of pure DL alanine encapsulated in a polyethylene microtube, which allows estimated doses of 10Gy to 200kGy. The advantages of this system are the low signal fading over a long period of time (over 90 days) and dose measurements above 150kGy. The main disadvantage is the difficulty in measures below 10Gy. In order to improve quality assurance services delivered in radiotherapy, commercial alanine dosimeters are being tested and compared with the already established system for measurements with time intervals longer than 90 days. The present work is an evaluation of the commercial L alanine dosimeter signal compared to the alanine dosimeter produced in IPEN. The dosimeters were irradiated with X ray and E beam and doses of 1, 10 and 20Gy. All measurements were performed following the same laboratory protocol based in ISO/ASTM guidelines. Environmental effects such as temperature, sensitivity to light and air humidity, and other storage conditions were evaluated. The results show that the decay of commercial dosimeters over 36 months was 11% higher than that observed in the dosimeter developed in IPEN, indicating the need for a correction factor for the comparison of dosimetry systems.

    Palavras-Chave: alanine-l; calibration; dosemeters; dosimetry; irradiation; radiation dose ranges; radiation doses

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  • IPEN-DOC 26137

    CARDOSO, JOAQUIM C.S. ; XAVIER, MARCOS . The whole body counting experience on the internal contamination of radionuclides at IPEN/CNEN-SP. In: INTERNATIONAL NUCLEAR ATLANTIC CONFERENCE, October 21-25, 2019, Santos, SP. Proceedings... Rio de Janeiro: Associação Brasileira de Energia Nuclear, 2019. p. 234-238.

    Abstract: The intake of radioactive material by workers can occur in the radiopharmaceuticals production, during the handling of radiopharmaceuticals in nuclear medicine and in bi ological and research laboratories. The members of staff occupationally exposed to radionuclides are routinely monitored for the purpose of quantitative assessment of internal exposure . Direct measurements of whole body and t hyroid contents provide an estimate of the activity of these radionuclides in the potentially exposed workers. The whole body measurements of the workers, trainees and visitors are routinely performed by the In Vivo Monitoring Laboratory (LMIV) of the Ener gy and Nuclear Research Institute (IPEN/CNEN SP). The frequency of measurements is defined by the Radioprotection Service (SRP) and the Dose Calculation Group of IPEN. For this purpose LMIV has two counters, whole body. NaI(Tl) (8x4”), and thyroid one, NaI (Tl) (3x3”). The system was calibrated in energy and efficiency, with calibration sources of Am 241, Co 60, Cs 137 and Eu 152 with gamma emissions between 59.54 and 1408.08 keV, positioned within Alderson Research Labs. anthropomorphic phantom. The backgro und measures were obtained of worker’s spectrum that wasn’t exposed occupationally yet. The concepts adopted in the HPS N13.30 Standard and proposed in ISO documents for standardization were used for activity measurements. During the period January 2014 to December 2018, approximately 3500 measurements had been carried in workers who develop tasks related to the production and research. The activities of the radionuclides and the workers’ tasks relationship had been evaluated.

    Palavras-Chave: calibration; dose equivalents; nai detectors; occupational exposure; personnel; radiation doses; radiation protection; radioisotopes; radionuclide kinetics; thyroid; whole-body counting; brazilian cnen

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  • IPEN-DOC 26136

    ANGELOCCI, LUCAS V. ; NOGUEIRA, BEATRIZ R. ; ABREU, RODRIGO T. ; ZEITUNI, CARLOS A. ; ROSTELATO, MARIA E.C.M. . End-weld thickness variation effects on dose rate for a new ir-192 brachytherapy source. In: INTERNATIONAL NUCLEAR ATLANTIC CONFERENCE, October 21-25, 2019, Santos, SP. Proceedings... Rio de Janeiro: Associação Brasileira de Energia Nuclear, 2019. p. 198-206.

    Abstract: Brachytherapy is a form of radiation therapy that uses small sealed sources close to the tumor to deliver a high dose to target while keeping dose on neighboring healthy tissues as low as possible. A wide variety of radionuclides and different sources are available for brachytherapy, each with his own unique geometry. The Laboratory of Sources Production for Radiotherapy (IPEN/CNEN) developed a new Ir-192 seed for eye tumor treatment that is currently under dosimetric definition. This work is part of a larger project that aims the full dosimetry of this new source, but rather than calculate the usual parameters proposed by the American Association of Physicists in Medicine, the specific contribution to the dose rate of a usually not considered factor was investigated under a statistical approach: end-weld thickness variation, which is important due to this source being welded by an in-house method. Its effects were investigated using the Monte Carlo radiation transport code MCNP4C and an in-house routine programmed with MATLAB® to analyze the data. Final results are presented as a mean value for dose rate at different points of interest and their associated standard deviations. The results are discussed based on the influence of said parameter on different points around the source.

    Palavras-Chave: brachytherapy; dose rates; dosimetry; eyes; iridium 192; monte carlo method; radiation source implants; sealed sources; thickness; welding

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  • IPEN-DOC 26135

    GONCALVES, JOSEMARY A.C. ; MANGIAROTTI, ALESSIO; BUENO, CARMEN C. . Comparative evaluation of the performance of thin diodes used as on-line dosimeters in radiation processing applications. In: INTERNATIONAL NUCLEAR ATLANTIC CONFERENCE, October 21-25, 2019, Santos, SP. Proceedings... Rio de Janeiro: Associação Brasileira de Energia Nuclear, 2019. p. 192-197.

    Abstract: In this work, we report a comparison between the performance of two samples of commercial PIN photodiodes (SFH206K from OsramÒ and S2506-04 from HamamatsuÒ) mainly addressing the variation of their current sensitivities with accumulated dose ranging from 0-15 kGy. All the results so far obtained have revealed that the radiation induced currents are linearly dependent on dose rates from 3.65 to 55.64 Gy/h. The current sensitivity of both unirradiated diodes (0.178 nA.h/Gy.mm3) slightly decreases with accumulated dose, namely 0.32%/kGy (SFH206K) and 1.4%/kGy (S2506-04). Although the SFH206K device compares favorably with the S2506-04, both diodes can be considered as a low budge alternative, good enough for on-line dosimetry applications in the field of radiation processing.

    Palavras-Chave: cobalt 60; comparative evaluations; dose rates; dosemeters; electrical faults; gamma radiation; performance; photodiodes; sensitivity

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  • IPEN-DOC 26134

    SANTOS, WILLIAM S. ; NEVES, LUCIO P.; PERINI, ANA P.; SANTOS, CARLA J.; BELINATO, WALMIR; CALDAS, LINDA V.E. . The influence of the lead eyewear geometry on the doses to the eye lens. In: ABEN (Ed.) INTERNATIONAL NUCLEAR ATLANTIC CONFERENCE, October 21-25, 2019, Santos, SP. Proceedings... Rio de Janeiro, 2019. p. 186-191.

    Abstract: The scattered radiation from interventional procedures is an important source of radiological risk for the medical staff. Considering all affected organs, the eye lens are among the most critical organs. As pointed out by several studies, even for low radiation doses, the appearance of cataract may occur. Considering this scenario, the radiation doses to the eye lens were determined using three different lead eyewear models commonly employed. The fluoroscopist was represented by an adult virtual anthropomorphic phantom (MASH3), coupled to the Monte Carlo code MCNP6.1™, in a typical cardiac interventional radiology procedure. The eyewear had 0.5 mmPb each, and the evaluation was carried out for four different beam angulations (PA, LAO90, LAO65 e RAO65), 80 kVp of tube voltage and HVL of 4 mmAl. The results pointed out that the shielding efficiency has a strong dependence on the eyewear type utilized, which may be very useful for the decision-making during the acquisition of such equipments.

    Palavras-Chave: crystalline lens; equivalent radiation doses; fluoroscopy; lead; monte carlo method; occupational exposure; phantoms; radiation protection; shielding

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  • IPEN-DOC 26133

    ABREU, RODRIGO T. ; ANGELOCCI, LUCAS V. ; NOGUEIRA, BEATRIZ R. ; SANTOS, HAMONA N. dos ; ZEITUNI, CARLOS A. ; ROSTELATO, MARIA E.C.M. . Anisotropy function of a new 192-Ir brachytherapy source. In: INTERNATIONAL NUCLEAR ATLANTIC CONFERENCE, October 21-25, 2019, Santos, SP. Proceedings... Rio de Janeiro: Associação Brasileira de Energia Nuclear, 2019. p. 175-185.

    Abstract: Brachytherapy is a type of radiotherapy that uses radioactive sources (seeds, wires, among others) close to the tumor. Is important to provide a detailed description of seed dosimetry, so only the tumor will be irradiated avoiding unnecessary dose on adjacent organs and structures. To evaluate the dosimetric parameter of the anisotropy function for a new brachytherapy source, this work proposes the use of microcube TLD-100 dosimeters to find the dose rate using the AAPM Task Group 43 protocol (TG-43). The anisotropy function represents dose distribution around the source and has a major role for characterization of a new iridium source being implemented in Brazil. The value of D(r,θ) was measured using Solid Water phantoms, r value being the distance from the geometric center of the source to the position of the dosimeter on the phantom, and θ being the angle formed between the longitudinal axis of the source and the line connecting the geometric center to the TLD. Monte Carlo calculations were performed to evaluate the anisotropy function to validate the experimental measurements. For each distance value (r), an anisotropy function was plotted (1.0, 2.0, 3.0, 4.0, 5.0, and 10.0 cm). The results obtained with Monte Carlo calculations agreed ±2% with the experimental values for r greater than 3.0 cm, so these results show a good distribution of dose around the seed considering the high energy of 192-Ir (average of 380 KeV) and encapsulation thickness.

    Palavras-Chave: anisotropy; brachytherapy; dose rates; dosimetry; iridium 192; monte carlo method; phantoms; radiation dose distributions; radiation source implants; sealed sources; thermoluminescent dosemeters

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  • IPEN-DOC 26132

    PRIMO, CAMILA de O. ; ANGELOCCI, LUCAS V. ; KARAM JUNIOR, DIB; ZEITUNI, CARLOS A. ; ROSTELATO, MARIA E.C.M. . Dose-rate constant and air-kerma strength evaluation of a new 125-I brachytherapy source using Monte-Carlo. In: INTERNATIONAL NUCLEAR ATLANTIC CONFERENCE, October 21-25, 2019, Santos, SP. Proceedings... Rio de Janeiro: Associação Brasileira de Energia Nuclear, 2019. p. 167-174.

    Abstract: Brachytherapy is a modality of radiotherapy which treats tumors using ionizing radiation with sources located close to the tumor. The sources can be produced from several radionuclides in various formats, such as Iodine-125 seeds and Iridium-192 wires. In order to produce a new Iodine-125 seed in IPEN/CNEN and ensure its quality, it is essential to describe the dosimetry of the seed, so when applied in a treatment the lowest possible dose to neighboring healthy tissues can be reached. The report by the AAPM’s Task Group 43 U1 is a document that indicates the dosimetry procedures in brachytherapy based on physical and geometrical parameters. In this study, dose-rate constant and air-kerma strength parameters were simulated using the Monte Carlo method radiation transport code MCNP4C. The air-kerma strength is obtained from an ideal modeled seed, since its actual value should be measured for seeds individually in a specialized lab with a Wide-Angle Free-Air Chamber (WAFAC). Dose-rate constant and air-kerma strength are parameters that depends on intrinsic characteristics of the source, i.e. geometry, radionuclide, encapsulation, and together they define the dose-rate to the reference point, defined as the dose-rate to a point 1 cm away from the geometric center of the source, in its transverse plane. This study presents the values found for these parameters with associated statistical uncertainty, and is part of a larger project that aims the full dosimetry of this new seed model, including experimental measures.

    Palavras-Chave: brachytherapy; computerized simulation; dose rates; dosimetry; iodine 125; kerma; monte carlo method

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  • IPEN-DOC 26131

    MAZER, AMANDA C ; SHORTO, JULIAN M.B. ; SIQUEIRA, PAULO T.D. ; NAKANDAKARI, MARCOS V.N.; RIBEIRO, VICTOR A.B.; YORIYAZ, HELIO . Interpolation studies of a 3D dosimetric system for quality assurance in radiation therapy. In: INTERNATIONAL NUCLEAR ATLANTIC CONFERENCE, October 21-25, 2019, Santos, SP. Proceedings... Rio de Janeiro: Associação Brasileira de Energia Nuclear, 2019. p. 153-160.

    Abstract: With the evolution of radiation therapy techniques, treatments have become increasingly accurate. To ensure a good quality assurance program for modern equipment, Sun Nuclear Corporation has developed ArcCHECK, a 3D dosimetric system, which contains 1386 helically arranged diodes within a PMMA cylindrical structure. The outputs of this system show, in addition to dose values acquired directly from the diodes, also matrices with interpolated dose values, in order to provide values at more than 5000 points for quality assurance. The main purpose of this work is to analyze the interpolated dose values provided by ArcCHECK. For this, simple measurements were taken with ArcCHECK, with a 10x10 cm2 static field of 6 MeV photons and 100 MU. A algorithm for MATLAB software was also developed so that it was possible to interpolate crude dose values obtained from the diodes and compare them with the values interpolated by the dosimetric system software. Significant dose differences values were found in the relative dose difference between the matrices interpolated by the algorithm and by ArcCHECK. The method used by this dosimetric system presented a diode selection pattern for the interpolation and different when compared to the developed method, even if both were calculated in the 2D plane, based on the dose map acquired by ArcCHECK.

    Palavras-Chave: algorithms; computerized simulation; dose rates; dosemeters; dosimetry; interpolation; monte carlo method; photons; quality assurance; radiation doses; radiotherapy

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  • IPEN-DOC 26130

    ISIDORO, ROBERTA A. ; SANTOS, GABRIEL S. dos; FONSECA, FABIO C. . CoNi/C electrocatalysts for alkaline fuel cell. In: BRAZILIAN MRS MEETING, 17th, September 16-20, 2018, Natal, RN. Abstract... São Carlos: Aptor Software, 2018. p. 228-228.

    Abstract: Solid alkaline fuel cell (SAFC) has been studied as possible alternatives in the production of electricity for portable and stationary applications. The oxygen reduction reaction (ORR) is key electrochemical processes, because his low kinetics decreases system efficiency. The main progresses in the cathodic side have been related to the development and improvement of activity and stability. In this way, non precious material has been studied, in the last years. Cobalt oxides have been reported to exhibit good performance for ORR. However, cobalt bimetallic can be more eficient catalysts for ORR, especially for its bifunctional function. Some Ni-based electrocatalysts have shown relevant good results for ORR in four-electron pathway. Song et al. Showed, for example, that Ni addition into Ag-based electrocatalysts for ORR decreases the ORR overpotential, while an increasing in the limiting current density is observed. In this way, a bimetallic CoNi/ C was produced to be used as a cathode in alkaline fuel cell.

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