REPOSITÓRIO DIGITAL DA PRODUÇÃO TÉCNICO CIENTÍFICA

 

 

 

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

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

 

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  • IPEN-DOC 27755

    MOREIRA, GREGORI de A. ; ANDRADE, IZABEL da S. ; CACHEFFO, ALEXANDRE ; LOPES, FABIO J. da S. ; YOSHIDA, ALEXANDRE C. ; GOMES, ANTONIO A. ; SILVA, JONATAN J. da ; LANDULFO, EDUARDO . Influence of a biomass-burning event in PM2.5 concentration and air quality: a case study in the Metropolitan Area of São Paulo. Sensors, v. 21, n. 2, p. 1-19, 2021. DOI: 10.3390/s21020425

    Abstract: Severe biomass burning (BB) events have become increasingly common in South America in the last few years, mainly due to the high number of wildfires observed recently. Such incidents can negatively influence the air quality index associated with PM2.5 (particulate matter, which is harmful to human health). A study performed in the Metropolitan Area of São Paulo (MASP) took place on selected days of July 2019, evaluated the influence of a BB event on air quality. Use of combined remote sensing, a surface monitoring system and data modeling and enabled detection of the BB plume arrival (light detection and ranging (lidar) ratio of (50 ± 34) sr at 532 nm, and (72 ± 45) sr at 355 nm) and how it affected the Ångström exponent (>1.3), atmospheric optical depth (>0.7), PM2.5 concentrations (>25 µg.m−3), and air quality classification. The utilization of high-order statistical moments, obtained from elastic lidar, provided a new way to observe the entrainment process, allowing understanding of how a decoupled aerosol layer influences the local urban area. This new novel approach enables a lidar system to obtain the same results as a more complex set of instruments and verify how BB events contribute from air masses aloft towards near ground ones.

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  • IPEN-DOC 27754

    SANTOS, ALLAN O.; RICCIARDI, JANAINA B.S.; PAGNANO, RODRIGO; PEREIRA, LUIS F.M.; SAKUMA, EMERSON T.; MATSUDA, MARGARETH M.N. ; BERNARDES, EMERSON S. ; ARAUJO, ELAINE B. ; BRUNETTO, SERGIO Q.; TAKAHASHI, MARIA E.S.; BRUNETTO, EDNA M.; ZULLI, ROBERTO; OZELO, MARGARETH C.; ETCHEBEHERE, ELBA C.S.C.. Knee radiosynovectomy with 153Sm‑hydroxyapatite compared to 90Y‑hydroxyapatite: initial results of a prospective trial. Annals of Nuclear Medicine, v. 35, n. 2, p. 232-240, 2021. DOI: 10.1007/s12149-020-01557-5

    Abstract: Introduction Radiosynovectomy (RS) with 90Y-hydroxyapatite (90Y-HyA) aims to control knee hemarthrosis in hemophiliac patients to prevent secondary arthropathy. However, knee RS using 153Sm-hydroxyapatite (153Sm-HyA) is considered less suitable due to the lower average soft tissue range and energy of 153Sm for large joints, such as the knees. Purpose The objective of this investigation was to assess the efficacy and safety of knee RS with 153Sm-HyA, compared to 90Y-HyA. Methods Forty patients were prospectively assigned to undergo knee RS with 153Sm-HyA (n = 19) or with 90Y-HyA (n = 21). The frequency of hemarthrosis episodes before and after treatment were compared. Results After six months of knee RS, 153Sm-HyA and 90Y-HyA promoted a similar reduction of hemarthrosis episodes (50% and 66.7%, respectively). However, after 12 months of knee RS, the reduction of hemarthrosis episodes was significantly (p = 0.037) higher using 153Sm-HyA (87.5%) compared to 90Y-HyA (50.0%). This discrepancy was more pronounced (p = 0.002) for 153Sm-HyA compared to 90Y-HyA in adults/adolescents. Conclusion Knee radiosynovectomy with 153Sm-HyA is safe, reduces hemarthrosis episodes after 12 months of treatments, especially in adults/adolescents and even with grades III/IV arthropathy, similar to 90Y-HyA. 90Y-HyA seems to promote better hemarthrosis control in small children.

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  • IPEN-DOC 27753

    KOHATSU, MARCIO Y.; PELEGRINO, MILENA T.; MONTEIRO, LUCILENA R. ; FREIRE, BRUNA M.; PEREIRA, RODRIGO M.; FINCHEIRA, PAOLA; RUBILAR, OLGA; TORTELLA, GONZALO; BATISTA, BRUNO L.; JESUS, TATIANE A. de; SEABRA, AMEDEA B.; LANGE, CAMILA N.. Comparison of foliar spray and soil irrigation of biogenic CuO nanoparticles (NPs) on elemental uptake and accumulation in lettuce. Environmental Science and Pollution Research, v. 28, n. 13, p. 16350-16367, 2021. DOI: 10.1007/s11356-020-12169-x

    Abstract: Nanoparticles (NPs) can be used in several ways in agriculture, including increasing production rates and improving nutritional values in plants. The present study aims to clarify how biogenic copper oxide nanoparticles (CuO NPs) applied by two routes of exposure (foliar spray and soil irrigation) affect the elemental uptake by lettuce. In vivo experiments using lettuce (n = 4) were performed with CuO NPs in comparison with copper salt (CuSO4), considering a final mass added of 20 mg of CuO per plant. The elemental composition of roots was mostly affected by the soil irrigation exposure for both Cu forms (NPs and salt). Neither Cu form added by soil irrigation was translocated to leaves. Copper concentration in leaves was mainly affected by foliar spray exposure for both Cu forms (NPs and salt). All Cu forms through foliar spray were sequestered in the leaves and no translocation to roots was observed. Foliar spray of CuO NPs caused no visual damage in leaves, resulted in less disturbance of elemental composition, and improved dry weight, number of leaves, CO2 assimilation, and the levels of K, Na, S, Ag, Cd, Cr, Cu, and Zn in leaves without causing significant changes in daily intake of most elements, except for Cu. Although Cu concentration increased in leaves by foliar spray of CuO NPs, it remained safe for consumption.

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  • IPEN-DOC 27752

    ALMEIDA, JORGE V. de; SILVA, EDUARDO C. da; MOSSO, MARBEY M.; SARTORI, CARLOS A.F. . A parametric study of inductive SWIPT systems assisted by metamaterial using virtual magnetic TL-based channel modeling. Journal of Microwaves, Optoelectronics and Electromagnetic Applications, v. 20, n. 1, p. 195-207, 2021. DOI: 10.1590/2179-10742021v20i1995

    Abstract: This paper presents a general methodology based on the description of the inductive channel as virtual magnetic transmission-lines (VMGTLs). In comparison with other existing methods, VMGTL approach presents a better physical insight of the channel behavior since the model correctly preserves the energy flow between the transmitting and receiving coils. Besides that, it facilitates the integration into the analysis of highly nonlinear and dispersive structures such as metamaterial (MTM) lenses. Particularly, the virtual-TL analogy clarifies that the enhancement of the transmission gain between any two coils assisted by MTM is not due to an enhanced coupling between the drivers, as usually claimed, but to the emergence of propagating near-field modes supported by the MTM. This approach, by means of a parametric study, also indicates, for the first time, that MTMs could be employed not only for the increasing of power but also of data transfer due to the emergence of a sub-resonant region of minimum distortion. Nonetheless, since both effects are mutually exclusive, no passive MTM structure could simultaneously improve power and data transmission.

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  • IPEN-DOC 27751

    SALES, T.S.N. ; BURIMOVA, A. ; RODRIGUES, P.S. ; MATOS, I.T. ; CABRERA-PASCA, G.A.; SAXENA, R.N. ; PEREIRA, L.F.D. ; OTUBO, L. ; CARBONARI, A.W. . Synthesis and characterization of Fe3O4-HfO2 nanoparticles by hyperfine interactions measurements. AIP Advances, v. 11, n. 1, p. 015047-1 - 015047-4, 2021. DOI: 10.1063/9.0000235

    Abstract: Nanoparticles (NPs) that combine biocompatibility and enhanced physical characteristics for biomedical applications are currently an area of intense scientific research. Hafnium oxide NPs are an innovative approach in the anticancer treatment by radiotherapy due to their low toxicity and enhancement of local dose in the tumor reducing the total radiation dose for the patient. The combination of this property with the excellent magnetic hyperthermia performance of Fe3O4 NPs can produce a promising nanomaterial for cancer therapy. In this work, we attempted to synthesize nanoscale samples of HfO2 doped with nominal 10 at.% Fe, and Fe3O4 doped with Hf at 10 at.% level using simple chemical routes. The crystal structure of the samples was characterized by X-ray diffraction. The material was irradiated with neutrons in a research reactor, the nuclear reaction 180Hf(n, γ)181Hf yielding the probe nucleus 181Hf(181Ta) used in the perturbed angular correlations experiments to measure hyperfine interactions. Despite their immediate response to the external magnetic field, at local level both samples showed only electric quadrupole interaction typical of the monoclinic hafnia indicating that Fe replaces Hf in HfO2 NPs, but, rather than substituting Fe, Hf enters magnetite in the form of HfO2 clusters. Transmission Electron Microscopy was exploited to study the morphology of these complex systems, as well as to localize hafnia clusters and understand the nature of their coupling to Fe3O4 specks.

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  • IPEN-DOC 27750

    ROSSI, MARIANA C.; BAYERLEIN, DANIEL L. ; BRANDAO, JAQUELINE de S.; PFEIFER, JOAO P.H.; ROSA, GUSTAVO dos S.; SILVA, WILLIAM de M.; MARTINEZ, LUIS G. ; SAEKI, MARGARIDA J.; ALVES, ANA L.G.. Physical and biological characterizations of TiNbSn/(Mg) system produced by powder metallurgy for use as prostheses material. Journal of the Mechanical Behavior of Biomedical Materials, v. 115, p. 1-10, 2021. DOI: 10.1016/j.jmbbm.2020.104260

    Abstract: Titanium scaffolds with non-toxic β stabilizing elements (Nb and Sn), Ti–34Nb–6Sn (TNS), and with magnesium as spacer (TNS/M), were processed by powder metallurgy, and sintered at 800 ◦C. The X-ray diffraction (XRD) pattern showed that materials are biphasic alloys, presenting 45 to 42% (wt %) in hcp (α-phase) and the rest is bcc (β-phase), and the presence of a slight peak relating to TiO2 in both materials. Pores of approximately 50 μm for TNS and 300 μm to TNS/M were observed in the micrographic analysis by scanning electron microscopy (SEM). The wettability was higher for TNS/M compared to TNS. The elastic modulus was higher for TNS compared to TNS/M. Stem cells derived from equine bone marrow (BMMSCs) were used for in vitro assays. The morphologic and adhesion evaluation after 72 h, carried out by direct contact assay with the materials showed that the BMMSCs were anchored and adhered to the porous scaffolds, in the way the cytoplasmic extension was observed. The cellular migration, using the “wound healing” method, was significant for the groups treated with conditioned medium with materials in 24 h. Osteogenic differentiation of BMMSCs, assessed by calcium deposition and staining with Alizarin Red, was greater in the conditioned medium with TNS/M in 10 days of culture. Since the biological effects was good and the elastic modulus decreased in the system with magnesium is a promising new content titanium alloy for biomedical application.

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  • IPEN-DOC 27749

    SILVA, FABIO F.A. da ; SANTOS, SOFIA N. dos ; PIJEIRA, MARTHA S.O. ; BERNARDES, EMERSON S. . Radiochemistry and pharmacokinetics of Pectin (MCP): a molecule with theranostics potential. In: CONGRESSO BRASILEIRO DE MEDICINA NUCLEAR, 34., 4-7 de setembro, 2020, Online. Resumo expandido... São Paulo, SP: Sociedade Brasileira de Medicina Nuclear, 2020.

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  • IPEN-DOC 27748

    SILVA, JOSE L. da ; MARTINS, PATRICIA de A. ; SANTOS, JOEL M. dos; SILVA, LAERCIO da ; SILVA, NATANAEL G. da ; FUKUMORI, NEUZA T.O. ; MATSUDA, MARGARETH M.N. . Determinação de estanho total por ICP-OES em reagentes liofilizados. In: CONGRESSO BRASILEIRO DE MEDICINA NUCLEAR, 34., 4-7 de setembro, 2020, Online. Resumo expandido... São Paulo, SP: Sociedade Brasileira de Medicina Nuclear, 2020.

    Abstract: O tecnécio-99m (99mTc) é o radioisótopo mais utilizado na medicina nuclear para obtenção de imagens para diagnóstico por SPECT. Seu estado de oxidação pode variar de -1 a +7, quando reage com uma variedade de compostos na presença de Sn(II).O cloreto estanoso diidratado é o agente redutor do 99mTc mais utilizado na formulação de reagentes liofilizados(RL). A determinação quantitativa de estanho total e Sn(II) são controles importantes para o processo de fabricação a fim de garantir a qualidade durante o prazo de validade dos RL. O objetivo deste trabalho foi quantificar o Sn total nos RL MDP-TEC e MIBI-TEC (IPEN) usando ICP-OES como método alternativo ao método colorimétrico descrito nas farmacopeias. As massas quantificadas de cloreto estanoso nos RL analisados estiveram compreendidas entre 90-110 % em relação ao descrito na bula do radiofármaco. O método analítico proposto por ICP-OES mostrou-se excelente para determinação de Sn total.

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  • IPEN-DOC 27747

    MARTINS, PATRICIA de A. ; SANTOS, JOEL M. dos; SILVA, JOSE L. da ; SILVA, LAERCIO da ; FUKUMORI, NEUZA T.O. ; ARAUJO, ELAINE B. de ; HIROMOTO, GORO ; MATSUDA, MARGARETH M.N. . Controle radionuclídico de radiofármacos de Lu-177. In: CONGRESSO BRASILEIRO DE MEDICINA NUCLEAR, 34., 4-7 de setembro, 2020, Online. Resumo expandido... São Paulo, SP: Sociedade Brasileira de Medicina Nuclear, 2020.

    Abstract: O lutécio-177 (Lu-177) é um radioisótopo produzido em reator, com meia-vida física (t/) de 6,73 dias e decaimento por emissão beta de 498,3 keV e raios y energias de 208,37 keV e 112,9 keV, adequados para o tratamento de câncer de tumores neuroendócrinos e de próstata. A determinação da pureza radionuclídica de radiofármacos de lutécio-177 visa verificar se a porcentagem de radionuclídeos atendem aos critérios estabelecidos na Farmacopeia Europeia (FE). Este trabalho tem por objetivo estabelecer as condições para realizar o controle radionuclídico de DOT-IPEN-177 produzido no IPEN-CNEN/ SP. Os resultados de identificação e pureza radionuclídica de DOT-IPEN-177 encontrados foram satisfatórios pois atenderam aos critérios estabelecidos na FE.

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  • IPEN-DOC 27746

    BALIEIRO, LUIZA M. ; BELLINI, MARIA H. ; ARAUJO, ELAINE B. de . Avaliação da biodistribuição do radiofármaco Fluorestradiol-18F em animais sadios e com modelo tumoral. In: CONGRESSO BRASILEIRO DE MEDICINA NUCLEAR, 34., 4-7 de setembro, 2020, Online. Resumo expandido... São Paulo, SP: Sociedade Brasileira de Medicina Nuclear, 2020.

    Abstract: O Fluorestradiol-18F (FES-18F) é um radiofármaco promissor para utilização, por método não-invasivo de tomografia de emissão de pósitrons (PET) no diagnóstico de câncer de mama ER+. Estudos pré-clínicos em animais sadios e com modelo tumoral desenvolvido com células MCF-7 apresentaram captação do FES-18F nos órgãos com receptores de estrogênio, tumor e significativa captação no fígado e intestinos, com perfil metabólico semelhante ao estradiol.

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  • IPEN-DOC 27745

    ASFORA, VIVIANE K.; ANTONIO, PATRICIA L. ; GONCALVES, JOSEMARY A.C. ; BUENO, CARMEN C. ; BARROS, VINICIUS S.M. de; OLIVEIRA, CHARLES N.P.; CALDAS, LINDA V.E. ; KHOURY, HELEN J.. Evaluation of TL and OSL responses of CaF2:Tm for electron beam processing dosimetry. Radiation Measurements, v. 140, p. 1-8, 2021. DOI: 10.1016/j.radmeas.2020.106512

    Abstract: The thermoluminescence (TL) and infrared stimulated luminescence (IRSL) responses of in-house produced CaF2:Tm dosimeters are investigated in this work, envisaging their application in electron beam (EB) radiation processing. The irradiations were performed at an industrial EB accelerator (1.5 MeV) covering a dose rate range of 2–8 kGy/s and dose up to 10 kGy. In general, the TL glow curves display four peaks, termed as peaks 2, 3, 4, and 5, corresponding to temperatures at ~150, 200, 240, and 300 °C, respectively. The intensity of the low-temperature peaks (2 and 3) grows with the dose, while the others remain constant (saturated). Nevertheless, an evident dose effect on the glow curves manifests in decreased peak3/peak2 ratio with increasing doses. The CW-IRSL curves exhibit similar patterns with an initial signal increase, followed by an exponential decay. Instead of the normal monotonic decays, these peak-shaped curves might be due to the charge capture competition between empty shallow traps and recombination centers. Both TL and IRSL intensities increase linearly with doses up to 6 kGy, and for higher doses, they become sub-linear with a saturation trend around 10 kGy. Another common feature of TL/IRSL response is its dose rate dependence, being more sensitive at higher dose rates. Despite being dose-rate dependent, the CaF2:Tm dosimeters might be suitable for EB processing dosimetry. However, for their use as routine dosimeters, relevant dosimetric characteristics, such as fading and response reproducibility, have to be investigated. Work in this direction is underway.

    Palavras-Chave: thermoluminescence; infrared radiation; luminescence; electron dosimetry; calcium fluorides; dosimetry; irradiation; evaluation

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  • IPEN-DOC 27744

    DUARTE, EDICLE de S.F.; FRANKE, PHILIPP; LANGE, ANNE C.; FRIESE, ELMAR; LOPES, FABIO J. da S. ; SILVA, JONATAN J. da ; REIS, JEAN S. dos; LANDULFO, EDUARDO ; SILVA, CLAUDIO M.S. e; ELBERN, HENDRIK; HOELZEMANN, JUDITH J.. Evaluation of atmospheric aerosols in the metropolitan area of São Paulo simulated by the regional EURAD-IM model on high-resolution. Atmospheric Pollution Research, v. 12, n. 2, p. 451-469, 2021. DOI: 10.1016/j.apr.2020.12.006

    Abstract: We present a high-resolution air quality study over São Paulo, Brazil with the EURopean Air Pollution Dispersion - Inverse Model (EURAD-IM) used for the first time over South America simulating detailed features of aerosols. Modeled data are evaluated with observational surface data and a Lidar. Two case studies in 2016 with distinct meteorological conditions and pollution plume features show transport (i) from central South America, associated to biomass burning activities, (ii) from the rural part of the state of São Paulo, (iii) between the metropolitan areas of Rio de Janeiro and São Paulo (MASP) either through the Paraíba Valley or via the ocean, connecting Brazil's two largest cities, (iv) from the port-city Santos to MASP and also from MASP to the city Campinas, and vice versa. A Pearson coefficient of 0.7 was found for PM10 at MASP CENTER and EURAD-IM simulations vary within the observational standard deviation, with a Mean Percentual Error (MPE) of 10%. The model's vertical distributions of aerosol layers agree with the Lidar profiles that show either characteristics of long-range transported biomass burning plumes, or of local pollution. The distinct transport patterns that agree with satellite Aerosol Optical Death and fire spot images as well as with the ground-based observations within the standard deviations, allows us exploring patterns of air pollution in a detailed manner and to understand the complex interactions between local to long-range transport sources.

    Palavras-Chave: air pollution; urban areas; evaluation; aerosols; atmospheres; air pollution monitoring; combustion; environmental impacts

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  • IPEN-DOC 27743

    COSTA, OSVALDO L. da ; SOUZA, DAIANE C.B. de ; CASTANHO, FABIO G. ; FEHER, ANSELMO ; MOURA, JOÃO A. ; SOUZA, CARLA D. ; OLIVEIRA, HENRIQUE B. ; MADUAR, MARCELO F. ; ZEITUNI, CARLOS A. ; ROSTELATO, MARIA E.C.M. . Gamma spectrometry of iodine-125 produced in IEA-R1 nuclear reactor, using HPGe detector and fixation into epoxy matrix disc. Applied Radiation and Isotopes, v. 169, p. 1-6, 2021. DOI: 10.1016/j.apradiso.2020.109568

    Abstract: Few places in the world produce iodine-125. In Brazil, the first production was achieved by using the IEA-R1 nuclear reactor located at Nuclear and Energy Research Institute – IPEN. To verify the quality of iodine-125 produced, and the amount of contaminants such as iodine-126, cesium-134 and caesium-137 among others, iodine-125 samples were immobilized into epoxy matrix disc, with the same geometry of a barium-133 reference radioactive source, used to calibrate an HPGe detector. The HPGe detector has a thin carbon composite window, which allows measure the iodine-125 photopeaks, between 27.1 and 35.4 keV. The method employed here was successful in producing and measurement of iodine-125.

    Palavras-Chave: contamination; gamma spectroscopy; high-purity ge detectors; iodine 125; irradiation; quality control; volatility; brazilian cnen

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  • IPEN-DOC 27742

    MIRANDA, ANA C.C. ; DURANTE, ANA C.R.; FUSCALDI, LEONARDO L.; BARBEZAN, ANGELICA B. ; LIMA, CILENE R. de; PERINI, EFRAIN ; ARAUJO, ELAINE B. de . Anti-HER2 monoclonal antibody based-radioimmunoconjugates: assessment of the chelating agent influence. Bioorganic & Medicinal Chemistry, v. 33, p. 1-9, 2021. DOI: 10.1016/j.bmc.2021.115996

    Abstract: In the present work, the radioimmunoconjugates 111In-DTPA-trastuzumab and 177Lu-DOTA-trastuzumab were evaluated regarding the influence of the chelating agents on the physical–chemical parameters and human epidermal growth factor receptor 2 (HER2) tumor cell binding. Data showed that both chelating agents, at predetermined molar ratios (antibody:chelator 􀀀 1:10 and 1:20), did not influence the immunoconjugates integrity, the radiolabeling process and the radiolabeled antibodies stability. However, differences were observed in the lipophilic feature between DOTA and DTPA radioimmunoconjugates and in the specific binding to SK-BR-3 tumor cells (HER2 positive). Therefore, this study showed the importance of assessing the influence of chelating agents and their molar ratios in the development process of radioimmunoconjugates.

    Palavras-Chave: tumor cells; neoplasms; drugs; therapeutic uses; radioimmunotherapy; chelating agents; radioisotopes

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  • IPEN-DOC 27741

    FONTES, E.H. ; RAMOS, C.E.D. ; OTTONI, C.A.; SOUZA, R.F.B. de ; ANTOLINI, E.; NETO, A.O. . Glycerol dehydrogenation steps on Au/C surface in alkaline medium: an in-situ ATR-FTIR approach. Renewable Energy, v. 167, p. 954-959, 2021. DOI: 10.1016/j.renene.2020.12.026

    Abstract: The glycerol oxidation reaction (GLYOR) was evaluated using an Au/C electrocatalyst under alkaline conditions and varying glycerol (GLY) concentration. This electrocatalyst was synthesized by the borohydride reduction method. Au/C was characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), and electrochemical techniques associated with in situ attenuated total reflectance Fourier transformed infrared spectroscopy (ATR-FTIR). XRD diffractograms showed the presence of Au (fcc). Cyclic voltammetry assisted by ATR-FTIR in situ measurements revealed that GLY oxidation on gold leads to the formation of a high amount of glyceraldehyde (GLYAD) for low GLY concentrations, while a lower amount of GLYAD was observed and the formation of dihydroxyacetone (DHA) was prevalent for high GLY concentrations. For high GLY concentrations DHA is almost stable, whereas for low GLY concentration DHA is fast oxidized to hydroxypyruvate. The excellent GLYOR activity of the Au/C catalyst in low GLY concentrations leads to the formation of deeper oxidized C1 species.

    Palavras-Chave: glycerol; dehydrogenation; gold; carbon; infrared spectrometers; fourier transform spectrometers; integral equations; oxidation; electrocatalysts; monosaccharides

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  • IPEN-DOC 27740

    SILVA, ANDERSON M.B.; SILVEIRA, WELLISSON S.; MATOS, TAWANY S.; JUNOT, DANILO O. ; REZENDE, MARCOS V.S.; SOUZA, DIVANIZIA N.. Effect of terbium and silver co-doping on the enhancement of photoluminescence in CaSO4 phosphors. Optical Materials, v. 111, p. 1-8, 2021. DOI: 10.1016/j.optmat.2020.110717

    Abstract: In this work, the photoluminescence properties of CaSO4 crystals co-doped with terbium and silver from silver oxide or silver nanoparticles (NPs) in different concentrations are investigated. Phosphors are obtained by means of a slow evaporation route and calcined at 600 °C for 1 h. X-ray diffraction analysis shows the formation of a single-phase anhydrite structure with orthorhombic symmetry. The photoluminescence properties are investigated using vacuum ultraviolet, ultraviolet and X-ray excitation. All luminescent measurements reveal the characteristic emissions of Tb3+. The analyses using excitation with ultraviolet light show that the Ag NPs are able to generate structural defects more satisfactorily compared to CaSO4:Tb with silver oxide. We also observe that higher concentrations of Ag increase the Tb3+ emission intensity, while higher concentrations of Ag NPs decrease it. The good stability of CaSO4 results in an efficient energy transfer from the host lattice to the activator under X-ray excitation, with the NPs contributing to the increase in luminescent intensity. Investigation of the terbium valence in the CaSO4 host shows a complete reduction of the Tb4+ present in Tb4O7 to Tb3+, as indicated by the X-ray absorption near edge structure. The vacuum ultraviolet excitation spectra reveal three broad bands, attributed to the charge-transfer excitations within SO42− complexes and to the 4f8 → 4f75d1 transitions on Tb3+. Our results also reveal that silver particles are responsible for generating deeper capture centers.

    Palavras-Chave: calcium sulfates; terbium; silver; phosphors; doped materials; photoluminescence; optical properties; crystals; nanoparticles; x-ray diffraction; ultraviolet radiation

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  • IPEN-DOC 27739

    MARUM, VICTOR J. de O.; REIS, LIVIA B.; MAFFEI, FELIPE S.; RANJBARZADEH, SHAHIN; KORKISCHKO, IVAN ; GIORIA, RAFAEL dos S.; MENEGHINI, JULIO R.. Performance analysis of a water ejector using Computational Fluid Dynamics (CFD) simulations and mathematical modeling. Energy, v. 220, p. 1-9, 2021. DOI: 10.1016/j.energy.2021.119779

    Abstract: A quasi-one-dimensional (1D) mathematical model coupled with Computational Fluid Dynamics (CFD) simulations of a water ejector is presented. Using data from CFD simulations, the mathematical model was used to calculate the friction loss coefficients of the ejector components, to predict its maximum efficiency point and to delimit its envelope of operation. The CFD approach was validated with experimental data and employed the finite element method to test the main turbulence models found in the literature (k-ε, k-u and k-u SST) for incompressible-flow ejectors. A set of operational conditions (OP) was tested and results show that the k-u SST turbulence model is the most suitable to capture the ejector flow characteristics in all OP. In addition, for higher entrainment ratio (M) values, it was observed a possible correlation between how well the boundary layer can be solved and how the model is able to capture the ejector efficiency curve. Moreover, for lower M values, another possible correlation may be stated between how the turbulence model is able to capture the velocity profile.

    Palavras-Chave: computerized simulation; fluid mechanics; mathematical models; performance testing; efficiency; water; friction

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  • IPEN-DOC 27738

    SANTOS, DIOGO F. dos ; SANTOS, ADIMIR dos . Zero-power noise up to 100 kHz in the IPEN/MB-01 research reactor facility. Annals of Nuclear Energy, v. 152, p. 1-16, 2021. DOI: 10.1016/j.anucene.2020.107974

    Abstract: Subcritical noise experiments at frequencies up to 100 kHz employing two distinct boron dilution in the reactor tank water (286.8 and 578.6 ppm of natural boron) were performed in the IPEN/MB-01 reactor. The Auto Power Spectral Densities (APSD) were inferred employing the IPEN/MB-01 Correlator and were best described by a four-mode decay model up to about 70 kHz. The analyses reveal that the first two modes were related to thermal neutron and the other two to the fast ones. The coupling between thermal and fast neutrons was weak, and they could be considered uncoupled. A two-region two-group kinetic model was built and for the first time important parameters, such as the subcritical reactivities, generation times, and the prompt neutron decay constants all in the core and reflector in the 286.8 ppm case were inferred. The experiments can be considered unique of its kind and the theory/experiment comparisons reached good agreements.

    Palavras-Chave: zero power reactors; reactor noise; ipen-mb-1 reactor; spectral density; criticality; frequency measurement; lifetime; neutrons

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  • IPEN-DOC 27737

    BENTO, RODRIGO T. ; CORREA, OLANDIR V. ; PILLIS, MARINA F. . On the surface chemistry and the reuse of sulfur-doped TiO2 films as photocatalysts. Materials Chemistry and Physics, v. 261, p. 1-7, 2021. DOI: 10.1016/j.matchemphys.2021.124231

    Abstract: The surface chemistry and recyclability of sulfur-doped titanium dioxide (TiO2) films was evaluated. The photocatalysts were grown by metalorganic chemical vapor deposition (MOCVD) at 400 ◦C. The films were sulfur-doped at 50 ◦C by using hydrogen sulfide (H2S) as sulfur source. The photocatalytic behavior of the films was measure by monitoring the methyl orange dye decolorization under visible light for several cycles. The films are formed only for the anatase crystalline phase. The results demonstrated that no structural modifications or significant differences in the morphology of the films occurred after their use. The sulfur-doped TiO2 films presented good photocatalytic activity, with an efficiency of 72.1% under visible light in its first use. The durability experiments suggest that even with the dye impregnation on the catalyst surface, the photocatalytic activity of the S-doped TiO2 films remained around 70% in the first 3 cycles, which allows their practical application for water treatment and purification under sunlight.

    Palavras-Chave: titanium oxides; sulfur; doped materials; films; vapor phase epitaxy; recycling; photocatalysis; surfaces; chemical vapor deposition

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  • IPEN-DOC 27736

    SANTOS, S.C. ; RODRIGUES JUNIOR, O. ; CAMPOS, L.L. . Towards a new promising dosimetric material from formation of thulium-yttria nanoparticles with EPR response. Materials Chemistry and Physics, v. 259, p. 1-7, 2021. DOI: 10.1016/j.matchemphys.2020.124005

    Abstract: Advances toward new materials for dosimetry application is essential to enhance quality assurance and quality improvement practices based on radiation protection concept. Face to this challenge the present work reports an approach to produce thulium-yttria nanoparticles with electron paramagntic resonance response by an alternative hydrothermal synthesis based on a relative low temperature and pressure. Distinct compositions of thulium-yttria nanoparticles with up to 2 at.%Tm (at.%, atomic percentage) were prepared and characterized by XRD, SEM, PCS, and EPR. The proposed synthesis method followed by thermal treatment of the precursor powder at 1100 ◦C for 2 h provided thulium-yttria nanoparticles with rounded shape, cubic C-type structure, and mean particle size (d50) less than 160 nm. Among all compositions formed, thulium-yttria nanoparticles prepared with 0.1%Tm presented the most remarkable EPR response. The production of fine thulium-yttria nanoparticles with EPR response supply meaningful parameters to advance in the formation of new dosimetry materials based on rare earths.

    Palavras-Chave: dosimetry; thulium oxides; yttrium; nanoparticles; rare earths; electron paramagnetic resonance; ceramics

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  • IPEN-DOC 27735

    ANDRADE, LUANA dos S.; OTUBO, LARISSA ; CASTANHEIRA, BRUNA; BROCHSZTAIN, SERGIO. Novel periodic mesoporous organosilicas containing pyromellitimides and their application for the photodegradation of asphaltenes. Microporous and Mesoporous Materials, v. 312, p. 1-8, 2021. DOI: 10.1016/j.micromeso.2020.110740

    Abstract: Periodic mesoporous organosilicas containing pyromellitic diimide units embedded in the pore walls (PMOPMI) were synthesized by co-condensation of the bridged silsesquioxane precursor N,N′-bis(3-triethoxysilylpropyl)pyromellitimide with tetraethoxysilane (TEOS) in acidic conditions, in the presence of the structure-directing agent Pluronics P-123. PMOPMI were also synthesized from the corresponding amic acid precursors. The PMOPMI were studied by different techniques, including N2 adsorption isotherms, transmission electron microscopy, infrared and diffuse reflectance spectroscopy and contact angles. The studied samples displayed well-organized 2D-hexagonal structures. The PMOPMI were able to adsorb petroleum asphaltenes from toluene solutions, and were efficient photosensitizers for the photodegradation of the adsorbed asphaltenes when irradiated. Most of the asphaltenes were removed from solutions by the combined action of adsorption and photodegradation processes.

    Palavras-Chave: porous materials; silica; nanocomposites; asphaltenes; photocatalysis; petroleum; ultraviolet radiation

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  • IPEN-DOC 27734

    GOTARDO, ANDRE T.; LIPPI, LUCIANA L.; VIOLIN, KALAN B. ; BEVILACQUA, ESTELA M.A.F.; GORNIAK, SILVANA L.. The effect of Ipomoea carnea on maternal reproductive outcomes and fetal and postnatal development in rats. Toxicon, v. 190, p. 3-10, 2021. DOI: 10.1016/j.toxicon.2020.11.012

    Abstract: Ipomoea carnea is a toxic plant found in Brazil and other tropical countries. The plant contains the alkaloids calystegines and swainsonine, which inhibit key cellular enzymes and cause systematic cell death. It is known that swainsonine is excreted in the amniotic fluid of dams exposed to the plant. Thus, the aim of this study was to verify whether the toxic effect of I. carnea on fetuses is due to exclusively the passage of the active principle of the plant through the placenta, or if the placentotoxic effect of swainsonine could collaborate in the adverse effects observed in the fetus. The teratogenic effects of exposure to the toxic principles of I. carnea were evaluated not only using the conventional protocol but also at later stages in the postnatal developmental period. Females were treated, from gestation day (GD) 6 until GD19, with 0.0, 1.0, 3.0 or 7.0 g/kg body weight of I. carnea dry leaves. The plant did not induce changes in reproductive performance or biochemical profile of the dams. Dams that received the highest dose of I. carnea showed cytoplasmic vacuolization in the liver, kidney and placental tissue. I. carnea promoted different lectin binding patterns in different areas of placental tissue. No fetal skeletal or visceral malformations was observed. The postnatal evaluation revealed a lower litter weight and a lower pup body weight one day after birth in the group that received the highest dose of I. carnea. Physical milestones were unaffected by the treatments. Female pups from all experimental groups exhibited a delay in achieving a negative geotaxis response. The results show that the toxic principle of I. carnea produces injury in utero in mothers and fetuses, but these deleterious effects were better demonstrated using postnatal evaluation.

    Palavras-Chave: toxicity; plants; reproduction; placenta; fetuses; teratogens; alkaloids; bioassay; tropical regions

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  • IPEN-DOC 27733

    OLIVEIRA, LUCAS N. de ; NASCIMENTO, ERIBERTO O. do; CALDAS, LINDA V.E. . New Fricke Xylenol Liquid detector doped with methylene blue (FXL-mblue) irradiated with red LED light. Journal of Luminescence, v. 230, p. 1-9, 2021. DOI: 10.1016/j.jlumin.2020.117730

    Abstract: In photodynamic therapy, a beam of incident light on the target causes interactions with the photosensitizing agent in the patient, subsequently killing cancerous cells through chemical and biological processes. The objective of this work was to describe for the first time the use of the FXL-mblue detector in dosimetric applications with irradiations from red LED light and using the UV–Vis spectrophotometry as an evaluation technique. The FXL-mblue samples were irradiated with doses of 2.40 kJ/cm2 up to 21.6 kJ/cm2 using a red LED light system. The results showed good results on uncertainties, sensitivity, reproducibility, repeatability, minimum detectable dose (MDD) and fading times for a promising dosimeter in measurements with visible light. In conclusion, the results indicate good dosimetric characteristics which could be used in quality control of photodynamic therapy measurements.

    Palavras-Chave: chemical dosemeters; dosemeters; xylenols; methylene blue; light emitting diodes; ultraviolet spectrometers; therapy; photosensitivity

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  • IPEN-DOC 27732

    GONCALVES, JOSEMARY A.C. ; MANGIAROTTI, ALESSIO; ASFORA, VIVIANE K.; KHOURY, HELEN J.; BUENO, CARMEN C. . The response of low-cost photodiodes for dosimetry in electron beam processing. Radiation Physics and Chemistry, v. 181, p. 1-8, 2021. DOI: 10.1016/j.radphyschem.2020.109335

    Abstract: The response of thin diodes (SFH206k) as dosimeters has been investigated employing the beam of an electron accelerator within the dose rate range of 2–8 kGy/s and accumulated doses up to 100 kGy. These devices, operating in the short-circuit mode and under industrial irradiation conditions, deliver current signals nonlinearly dependent on the dose rate, whichever the dose history of the diodes, due to the high density of the generated electron-hole pairs herein achieved. Despite this nonlinearity, the dose rate response is stable and characterized by current signals with repeatability better than 2.0%, regardless of the accumulated dose. It is also found that the dose responses are quite linear with sensitivities slightly dependent on the accumulated dose at a constant dose rate. The decrease in the charge sensitivity, taking as reference that obtained before any radiation damage, reaches only 9% (k = 2) at 100 kGy, which is much smaller than the values reported in the literature. From this low aging and the repeatability of both dose rate and dose responses, it seems that the photodiode under investigation is a low budget alternative, good enough for routine dosimetry, provided it has been previously calibrated in the same processing facility.

    Palavras-Chave: photodiodes; dosimetry; electron beams; dosemeters; electron dosimetry; si semiconductor detectors; dose rates

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  • IPEN-DOC 27731

    MENDES, BRUNO M.; ANTUNES, PAULA C.G. ; BRANCO, ISABELA S.L. ; NASCIMENTO, EDUARDO do; SENIWAL, BALJEET; FONSECA, TELMA C.F.; YORIYAZ, HELIO . Calculation of dose point kernel values for monoenergetic electrons and beta emitting radionuclides: intercomparison of Monte Carlo codes. Radiation Physics and Chemistry, v. 181, p. 1-8, 2021. DOI: 10.1016/j.radphyschem.2020.109327

    Abstract: Targeted radionuclide therapy (TRT) and beta-emitting seeds brachytherapy (BSBT) exploit the characteristics of energy deposited by beta-emitting radionuclides. Monte Carlo (MC) modelling of electron transport is crucial for calculations of absorbed dose for TRT and BSBT. However, computer codes capable of providing consistent results are still limited. Since experimental validations show several difficulties, the estimation of electron dose point kernel (DPK) is often used to verify the accuracy of different MC codes. In this work, we compared DPK calculations for various point, isotropic and monoenergetic electron sources and several beta-emitting radioisotopes using the codes MCNP, EGSnrc, PENELOPE and TOPAS with different simulation options. The simulations were performed using latest versions of EGSnrc and Penelope, TOPAS version 3.3.1 and MCNP version 6.1 Monte Carlo codes. In our simulations, the geometrical model consists of a point electron source placed at the center of a water sphere emitting isotropically. The water sphere was divided into 28 shells and the energy deposition was scored within these shells. The radius of the outermost shell was 1.2R0, where R0 is the continuous slowing down approximation (CSDA) range. Five monoenergetic beta sources with energies of 0.05, 0.1, 0.5, 1 and 3 MeV were studied. Six beta-emitting radionuclides were also simulated: Lu-177, Sm-153, Ho-166, Sr-89, I-131 and Y-90. Monoenergetic electron simulations showed large deviations among the codes, larger than 13% depending on the electron energy and the distance from the source. In the cases where beta spectra of radionuclides were simulated, all MC codes showed differences from EGSnrc (used as reference value - RV) less than 3% within rE90 range (radius of the sphere in which 90% of the energy of the spectrum electrons would be deposited). TOPAS showed results comparable to EGSnrc and PENELOPE. DPK values for 0.1 MeV monoenergetic electrons, calculated using MCNP6, led to differences higher than ±5% from RV despite our attempts to tune electron transport algorithms and physics parameters.

    Palavras-Chave: point kernels; computer calculations; computerized simulation; electron emission; electrons; beta particles; radionuclides; monte carlo method; therapy; brachytherapy

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  • IPEN-DOC 27730

    MANGIAROTTI, A.; PETRI, A.R.; MALAFRONTE, A.A.; GONCALVES, J.A.C. ; BARROS, S.F.; BUENO, C.C. ; FERNANDEZ-VAREA, J.M.; MAIDANA, N.L.; MARTINS, M.N.; VANIN, V.R.. A low-cost small-size commercial PIN photodiode: II. Comparison of measurements with monoenergetic electrons to analytical expressions and Monte Carlo simulations. Radiation Physics and Chemistry, v. 182, p. 1-20, 2021. DOI: 10.1016/j.radphyschem.2020.109102

    Abstract: Commercial PIN photodiodes, repurposed as particle detectors, have received a lot of attention along the past decades because they can offer a low-cost solution suitable for several applications. The BPX-65 photodiode has been chosen because of its interesting features for measuring electrons in a harsh radiation environment close to the beam of an accelerator. Its electrical characterisation and its application to photon spectrometry have been presented in the companion paper I. Here, its response function (RF) to electrons is investigated using the beam from an electron accelerator with a small energy spread. The empirical expressions for the RF available in the literature have been improved, simplified, and combined to obtain a final form with 7 free parameters: 4 non-linear and 3 linear. A special fitting procedure, which takes advantage of the presence of the linear parameters, is described. The behaviour of these parameters with beam energy and bias is investigated to uncover the physical origin of the three components included in the proposed RF. The interpretation of the features of the spectra is confirmed by Monte Carlo simulations carried out employing the general-purpose PENELOPE/penEasy package. To take into account the charge-collection properties of the device, a simple model has been implemented and is compared to data. It has then been possible to estimate the thickness of the partially dead layer from the experiment.

    Palavras-Chave: photodiodes; silicon; monte carlo method; plasma; experiment planning; response functions

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  • IPEN-DOC 27729

    RODRIGUES, FLAVIO T.; KOIKE, AMANDA C.R. ; SILVA, PAMELA G. da ; NEGRAO, BIANCA G. ; ALENCAR, SEVERINO M. de; MANCINI FILHO, JORGE; VILLAVICENCIO, ANNA L.C.H. . Effects of electron beam irradiation on the bioactive components of goji-berry. Radiation Physics and Chemistry, v. 179, p. 1-5, 2021. DOI: 10.1016/j.radphyschem.2020.109144

    Abstract: The goji-berry (Lycium barbarum) is an oval-shaped orange-red fruit with a slightly sweet flavor. This berry has a high antioxidant potential and presents interesting nutritional and therapeutic properties. Irradiation is a safe method that has long used to reduce the microbiological contamination of dried and dehydrated food products. This study aimed to evaluate the irradiation effects on the bioactive compounds of goji berries by irradiating samples with an electron beam at doses of 2.5, 5.0, 7.5, and 10.0 kGy. The 2,2-diphenyl-1-picrylhydrazyl (DPPH) scavenging activity and oxygen radical absorbance capacity (ORAC) were assessed by analyzing the hydroalcoholic extracts. The total phenolic compounds determined by the Folin-Ciocalteu assay. Doses up to 10.0 kGy did not significantly affect the antioxidant activity in the DPPH assay, and electron beam irradiation improved the total antioxidant activity of the samples in ORAC, as well as a total flavonoid and phenolics assays.

    Palavras-Chave: electron beams; irradiation; fruits; ionizing radiations; food additives; antioxidants; food processing; safety; food industry

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  • IPEN-DOC 27728

    BERBEL, GLAUCIA B.B.; HORTELLANI, MARCOS A. ; SARKIS, JORGE E. de S. ; CHIOZZINI, VITOR G.; FAVARO, DEBORAH I.T. ; SUTTI, BRUNO O.; SAKAZAKI, NIXON C.; BRAGA, ELISABETE de S.. Emerging contaminants (Rh, Pd, and Pt) in surface sediments from a Brazilian subtropical estuary influenced by anthropogenic activities. Marine Pollution Bulletin, v. 163, p. 1-13, 2021. DOI: 10.1016/j.marpolbul.2020.111929

    Abstract: The concentrations of Platinum (Pt), Rhodium (Rh) and Palladium (Pd) were evaluated from a highly impacted estuary in Brazil influenced by industrial pole, highway traffic and sewage outfall. The Santos-São Vicente region presents important economic activities derived from a largest harbor of Latin America and an industrial pole surrounded by intensive highway traffic. Values of Rh varied from 0.08 to 1.7 ng g−1 with highest values at stations impacted by domestic waste. Pt ranged from 0.15 to 40.3 ng g−1 with highest concentrations located close to the ferryboat traffic. Pd levels varied from 1.05 to 22.0 ng g−1 with values >5 ng g−1 in 50% of the stations. The spatial distribution of PGEs was not always directly associated with muddy sediments, because high PGE levels found even in sandy sediments. Pollution indexes, including anthropogenic factor (AF), geoaccumulation index (Igeo), Enrichment factor (EF), and Pollution Load Index (PLI) were used for evaluating contaminant potential. Based on EF, Igeo, and PLI, 50% of samples of the sediments from Santos-São Vicente Estuarine System (SSV) were classified with significant to strong PGE contamination. All stations on the Santos Channel (SC), São Vicente Channel (SVC) and Bertioga Channel (BC) had AF higher than 80% in at least one of PGE elements, as showed in station 2A, which presented AF <50% for Rh and Pd and 86% for Pt. Despite high anthropogenic enrichment, no correlations among PGE elements were observed in surface sediments. Only two stations presented Pd/Pt, Pt/Rh, and Pd/Rh typical ratios of auto catalyst (st. 14 and Piaçaguera) both located in the vicinity of highways. This could be due to the PGE deposition process in road dust, soil, and water as well as the biogeochemical cycling of PGEs involving organic metallic and inorganic complexes formed in the estuarine and seawaters.

    Palavras-Chave: estuaries; sediments; indexes; environment; coastal regions; water pollution; coastal waters; platinum; rhodium; palladium; chemical composition

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  • IPEN-DOC 27727

    OLIVEIRA, MARIA J.A. de ; VILLEGAS, GETHZEMANI M.E.; MOTTA, FLAVIA D.; FABELA-SANCHEZ, OMAR; ESPINOSA-ROA, ARIAN; FOTORAN, WESLEY L.; PEIXOTO, JANAINA C.; TANO, FABIA T.; LUGAO, ADEMAR B. ; VASQUEZ, PABLO A.S. . Influence of gamma radiation on Amphotericin B incorporated in PVP hydrogel as an alternative treatment for cutaneous leishmaniosis. Acta Tropica, v. 215, p. 1-8, 2021. DOI: 10.1016/j.actatropica.2020.105805

    Abstract: Amphotericin B (Amph-B) is an antifungal drug used intravenously for the treatment of leishmaniasis. Side-effects from Amph-B treatment can arise such as cardiac arrhythmia and renal dysfunctions, which will lead to discontinuation of treatment. Unfortunately, patients in endemic countries do not have access to alternative therapies. The objective of this study was to analyze the effects of Cobalt-60 gamma irradiation on crosslinking polymeric hydrogels (Hydg) and the incorporation of Amph-B into the gel as a controlled-release drug delivery alternative. Polyvinylpyrrolidone (PVP)/Amph-B solutions were irradiated with 15 kGy at 0 °C and 25 °C. The drug's stability was ascertained by UV–visible spectrometry, liquid chromatography/mass spectrometry and proton nuclear magnetic resonance. Irradiated Hydg/Amph-B achieved similar stability to the standard Amph-B solution and was enough to promote hydrogel crosslinking. In vitro trials were carried out to ensure Amph-B was still biologically active after irradiation. The results from flow cytometry and MTT assay show that Amph-B had an IC50 = 16.7 nM. A combination of Hydg at 1.324 gmL−1 and Amph-B at 25.1 nM for 24 h lead to the greatest inhibition of L. amazonensis promastigotes, and could be used as an alternative treatment method for cutaneous leishmaniosis.

    Palavras-Chave: antimicrobial agents; gamma radiation; hydrogels; drugs; delivery; parasitic diseases; irradiation

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  • IPEN-DOC 27726

    LOPEZ-SAUCEDO, FELIPE; FLORES-ROJAS, GUADALUPE G.; VARCA, JUSTINE P.R.O. ; VARCA, GUSTAVO H.C. ; BUCIO, EMILIO. Antimicrobial materials and devices for biomedical applications. In: UR-RAHMAN, ATTA (Ed.). Frontiers in Clinical Drug Research: Anti-Infectives. Singapore: Bentham Science Publishers, 2020. p. 78-126, v. 6, cap. 3. DOI: 10.2174/9789811425745120060005

    Abstract: Bioaccumulation in sanitary devices, caused by opportunistic pathogens, intervenes negatively in the recovery of a patient since these are able to provoke a mild or life-threatening infection. Thus, surfaces of certain materials such as gauzes, catheters, sutures, etc., which are adjacent or directly exposed to a healing zone, are prone to become sites for the growth, proliferation, and spread of pathogenic microorganisms. Although in surgical or healing processes, sterile materials are usually applied, the time of contact with biological interfaces is long enough to make the sterilization but not enough to control and prevent an infection since pathogens abound in the surroundings. Air, water, and soil can be potential vectors, without considering those factors related to iatrogenesis that also play a role in the opportunities for the patient's recovery. Within this context, engineered materials are currently being developed and explored towards devices and biomaterials with improved design, performance, duration, biocompatibility aiming to be safer for the user. The surface functionalization of materials with antimicrobial agents is a highlighted alternative to overcome this issue. This chapter addresses current antimicrobial materials, as well as strategies for obtaining antimicrobial surfaces and coating as well as their properties. In addition, the safety assessment of biomedical applications and international standards are discussed.

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  • IPEN-DOC 27725

    VIEIRA, RAPHAEL R. da C.F. ; VICENTE, ROBERTO . Caracterização geológica de sítios para um repositório profundo de rejeitos radioativos. São Paulo: Instituto de Pesquisas Energéticas e Nucleares - GRR, Dezembro, 2020. (IPEN/GRR-REL-01/21). Restrito.

    Título do projeto: Relatório Técnico de Iniciação Científica

    Abstract: O presente trabalho tem como finalidade contribuir para o desenvolvimento de métodos, no Serviço de Gerência de Rejeitos Radioativos do Instituto de Pesquisas Energéticas e Nucleares- IPEN, direcionados à identificação de áreas potenciais para a instalação de repositórios do tipo poço tubular profundo, destinados à deposição de fontes seladas em desuso. Trata-se de exercício para avaliar a viabilidade de instalação de um repositório sobre o recorte regional referente ao alto e médio Vale do Rio Paraíba do Sul, utilizado como modelo para o objeto de análise, segundo os requisitos da segurança do homem e do meio ambiente, em curto e em longo prazo, e conforme os critérios estabelecidos pela norma CNEN NE 6.06. Resolução CNEN 014/89 - Seleção e Escolha de Locais para Depósitos de Rejeitos Radioativos, de janeiro de 1990.

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  • IPEN-DOC 27724

    OLIVA, AMAURY M.; ALVES FILHO, HERMES; HERNANDEZ, CARLOS R.G.; MORAES, LEONARDO R. da C.. Método Espectral Determinístico para problemas de transporte de nêutrons na formulação SN, multigrupo de energia, geometria unidimensional, espalhamento anisotrópico e fonte fixa / The multigroup Spectral Deterministic Method for SN neutron transport theory in slab geometry, anisotropic scattering with fixed-source problems. Revista Cereus, v. 12, n. 2, p. 277-291, 2020. DOI: 10.18605/2175-7275/cereus.v12n2p277-291

    Abstract: Neste artigo é apresentada uma nova metodologia numérica contemplando o desenvolvimento de um método da classe dos espectro-nodais (malha grossa) para a solução de problemas de transporte de nêutrons na formulação das ordenadas discretas (𝑆𝑁), em geometria unidimensional, considerando o espalhamento anisotrópico, fonte fixa e multigrupo de energia. O método, denominado Método Espectral Determinístico (MED), baseia-se, inicialmente, na análise espectral das equações de transporte de nêutrons 𝑆𝑁. As incógnitas dessa metodologia são os fluxos angulares nos contornos e o fluxo angular médio no interior dos nodos espaciais. Os valores numéricos obtidos para essas grandezas, a menos dos erros da aritmética finita computacional, concordam com a solução analítica da equação de transporte 𝑆𝑁 no domínio espacial utilizado. Os resultados numéricos são mostrados e comparados com o tradicional método de malha fina, DD,cf., Diamond Difference e os métodos nodais SGF, cf., spectral Green’s function e o método FN para ilustrar a precisão numérica nos resultados obtidos pelo MED.

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  • IPEN-DOC 27723

    TORRES, WALMIR M. ; UMBEHAUN, PEDRO E. ; MATTAR NETO, MIGUEL ; BELCHIOR JUNIOR, ANTONIO ; FREITAS, ROBERTO L. . RMB experimental program on the hydrodynamical behavior of fuel assemblies. Brazilian Journal of Radiation Sciences, v. 8, n. 3A, p. 1-12, 2020. DOI: 10.15392/bjrs.v8i3A.1555

    Abstract: The Brazilian Multipurpose Reactor - RMB is a 30 MW pool type research reactor, that uses Materials Testing Reactor - MTR type fuel assemblies. It has a 5x5 square array core with 23 fuel assemblies and two in-core irradiation positions, operating with upward flow and average velocities nearly 10 m/s in the fuel plates channels. The IEA-R1 is a 5 MW pool type research reactor, which also has a 5x5 square array core with 19 standard fuel assemblies, four control fuel assemblies and a central beryllium irradiation device. It operates with downward flow nearly 1.8 m/s in the channels. In order to verify and provide data and information about the dynamical behavior of fuel assemblies under nominal and critical conditions, the experimental circuit ORQUÍDEA is being designed. This circuit will permit upward and downward flow and dynamical behavior of the fuel assemblies and its parts will be tested and verified. Flow rate, temperature, pressure and differential pressure transducers are the instruments of the circuit. Endurance and critical flow velocity tests will be performed. The COLIBRI experimental circuit is being designed to make tests that allow the studies of the fluid-structure phenomenology of fuel plates similar to those of the RMB fuel assemblies when subjected to high flow velocities, which can induce pressure differences between the channels formed by the fuel plates. This work presents a preliminary design for the ORQUÍDEA and COLIBRI experimental circuits to be built at the Instituto de Pesquisas Energéticas e Nucleares - IPEN of the Comissão Nacional de Energia Nuclear - CNEN.

    Palavras-Chave: comparative evaluations; computerized simulation; critical flow; critical velocity; experimental data; finite element method; flow rate; fuel assemblies; fuel plates; hydrodynamics; pressure range mega pa 10-100; rmb reactor; temperature range 0065-0273 k; temperature range 0400-1000 k

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  • IPEN-DOC 27722

    GABE, CESAR A.; FREIRE, LUCIANO O. ; ANDRADE, DELVONEI A. de . Modeling dynamic scenarios for safety, reliability, availability, and maintainability analysis. Brazilian Journal of Radiation Sciences, v. 8, n. 3A, p. 1-11, 2020. DOI: 10.15392/bjrs.v8i3A.1464

    Abstract: Safety analysis uses probability combinatorial models like fault tree and/or event tree. Such methods have static basic events and do not consider complex scenarios of dynamic reliability, leading to conservative results. Reliability, availability, and maintainability (RAM) analysis using reliability block diagram (RBD) experience the same limitations. Continuous Markov chains model dynamic reliability scenarios but suffer from other limitations like states explosion and restriction of exponential life distribution only. Markov Regenerative Stochastic Petri Nets oblige complex mathematical formalism and still subject to state explosions for large systems. In the design of complex systems, distinct teams make safety and RAM analyses, each one adopting tools better fitting their own needs. Teams using different tools turns obscure the detection of problems and their correction is even harder. This work aims to improve design quality, reduce design conservatism, and ensure consistency by proposing a single and powerful tool to perform any probabilistic analysis. The suggested tool is the Stochastic Colored class of Petri Nets, which supplies hierarchical organization, a set of options for life distributions, dynamic reliability scenarios and simple and easy construction for large systems. This work also proposes more quality rules to assure model consistency. Such method for probabilistic analysis may have the effect of shifting systems design from “redundancy, segregation and independency” approach to “maintainability, maintenance and contingency procedures” approach. By modeling complex human and automated interventional scenarios, this method reduces capital costs and keeps safety and availability of systems.

    Palavras-Chave: availability; computerized simulation; dynamical systems; maintenance; probabilistic estimation; redundancy; reliability; safety analysis; sensitivity analysis; stochastic processes

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  • IPEN-DOC 27721

    NIELSEN, G.F. ; MORAIS, N.W.S. ; LIMA, N.B. . Crystallographic texture of hot rolled uranium-molybdenum alloys. Brazilian Journal of Radiation Sciences, v. 8, n. 3A, p. 1-14, 2020. DOI: 10.15392/bjrs.v8i3A.1406

    Abstract: The uranium molybdenum (U-Mo) alloys have the potential to be used as low enriched uranium nuclear fuel in research, test, and power nuclear reactors. U-Mo alloy with composition between 7 and 10 wt% molybdenum shows excellent body centered cubic phase (γ phase) stabilization and presents a good nuclear fuel testing performance. Hot rolling is commonly utilized to produce nuclear fuel plate where it promotes the cladding and the fuel alloy bonding. The mechanical deformation generates crystallographic preferential orientation, the texture, which influences the material properties. This work studied the texture evolution in hot rolled U-Mo alloys. The U7.4Mo and U9.5Mo alloys were melted in a vacuum induction furnace, homogenized at 1000°C for 5 h, and then hot rolled at 650°C in three height reductions: 50, 65 and 80%. The crystalline phases and the texture were evaluated by X-ray diffraction (XRD). The as-cast and processed alloys microstructures were characterized by optical and electronic microscopies. The as-cast, homogenized, and deformed alloys have the γ phase. It was found microstructural differences between the U7.4Mo and U9.5Mo alloys. The homogenized treatment showed effective for microsegregation reduction and was not observed substantial grain size increasing. The deformed uranium molybdenum alloys presented α, γ, θ texture fibers. The intensity of these texture fibers changes with rolling reduction.

    Palavras-Chave: chemical composition; crystal structure; deformation; microstructure; molybdenum alloys; nuclear fuels; optical microscopy; rolling; scanning electron microscopy; texture; uranium alloys; x-ray diffraction

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  • IPEN-DOC 27720

    SMITH, RICARDO B. ; SACHDEVA, MAHIMA; BISURI, INDRANIL; VICENTE, ROBERTO . Advanced heavy water reactor: a new step toward sustainability. Brazilian Journal of Radiation Sciences, v. 8, n. 3A, p. 1-18, 2020. DOI: 10.15392/bjrs.v8i3A.1368

    Abstract: One of the great advances in the current evolution of nuclear power reactors is occurring in India, with the Advanced Heavy Water Reactor (AHWR). It is a reactor that uses thorium as part of its fuel, which in its two fueling cycle options, in conjunction with plutonium or low enriched uranium, produces energy at the commercial level, generating less actinides of long half-life and inert thorium oxide, which leads to an optimization in the proportion of energy produced versus the production of burnt fuels of the order of up to 50%. The objective of this work is to present the most recent research and projects in progress in India, and how the expected results should be in compliance with the current sustainability models and programs, especially the "Green Chemistry", a program developed since the 1990s in the United States and England, which defines sustainable choices in its twelve principles and that can also be mostly related to the nuclear field. Nevertheless, in Brazil, for more than 40 years there has been the discontinuation of research for a thorium-fueled reactor, and so far there has been no prospect of future projects. The AHWR is an important example as an alternative way of producing energy in Brazil, as the country has the second largest reserve of thorium on the planet.

    Palavras-Chave: fuel element clusters; hwlwr type reactors; nuclear fuels; radioactive wastes; reactor design; sustainable development; thorium; india

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  • IPEN-DOC 27719

    SMITH, R.B. ; SALVETTI, T.C. ; TESSARO, A.P.G. ; MARUMO, J.T. ; VICENTE, R.V. . Knowledge management in the decommissioning of nuclear facilities in Brazil. Brazilian Journal of Radiation Sciences, v. 8, n. 3A, p. 1-15, 2020. DOI: 10.15392/bjrs.v8i3A.1315

    Abstract: In the second half of the twentieth century in Brazil, several nuclear facilities were built for the most varied objectives. The largest number of such facilities is at the Nuclear and Energy Research Institute in São Paulo (IPEN-CNEN/SP). For different reasons, some of these facilities had their projects finalized and were deactivated. Some of the equipment was then dismantled, but the respective nuclear and radioactive material remained isolated in the original sites waiting for the proper decommissioning procedures. The Celeste Project is an example of a facility where the nuclear material has been kept, and is subject to Argentine-Brazilian Agency for Accounting and Control of Nuclear Materials (ABACC) periodic inspections. Because of a number of interests, including financial and/or budgeting situations at the institutions, decades have passed without any further action; the people who originally worked there, and possessed information and knowledge about these facilities, have already moved away from the area, or are in the process of. Therefore, because of the absence of knowledge management techniques in force at the time of establishing and operating these installations, this work proposes an analysis about the possible consequences in case of loss of perhaps the only one remaining knowledge, the one from the people who designed those departments and worked there.

    Palavras-Chave: decommissioning; historical aspects; information dissemination; information needs; knowledge management; nuclear facilities; radioactive materials; radioactive waste management; safety; brazilian cnen

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  • IPEN-DOC 27718

    PUGLIESI, R. ; STANOJEV PEREIRA, M.A. ; ANDRADE, M.L. . Concentration and distribution of oil in the reservoir mineral Dolomite studied by neutron tomography. Brazilian Journal of Radiation Sciences, v. 8, n. 3A, p. 1-12, 2020. DOI: 10.15392/bjrs.v8i3A.1291

    Abstract: Neutron Tomography – NT is a non-destructive technique, ideal for imaging hydrogen-rich substances even when wrapped up by thick rock layers. In the present study, the NT was employed for investigating the oil concentration and distribution in the mineral Dolomite, a natural oil reservoir. Two types of Dolomite samples, one of which dry, and the second one in oil-saturated were prepared. The applied oil was EMCAplus® 070 usually employed in permeability experiments to reproduce conditions of natural oil reservoirs. Three small fragments of the dry sample and three of the oil sample were inspected by NT and the comparison between the obtained results enabled, to distinguish several regions in which the oil is stored, to indicate that the oil is dispersed throughout the volume of the samples, and to quantify the storage concentration. The obtained data for oil concentration, for the three fragments, were compared to each other and to the one obtained by the conventional gravimetric technique, and they agreed within their uncertainties, demonstrating the viability of the NT technique to inspect, either in a qualitative as in a quantitative level, this oil reservoir mineral.

    Palavras-Chave: concentration ratio; distribution; dolomite; neutrons; petroleum; petroleum deposits; prospecting; scanning electron microscopy; tomography

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  • IPEN-DOC 27717

    CURBELO, J.P.; LIBOTTE, R.B.; OLIVA, A.M.; BARROS, R.C.; ALVES FILHO, H.. The modified spectral deterministic method applied to fixed–source discrete ordinates problems in X, Y–geometry. Brazilian Journal of Radiation Sciences, v. 8, n. 3A, p. 1-14, 2020. DOI: 10.15392/bjrs.v8i3A.1268

    Abstract: A new approach for the application of the coarse–mesh Modified Spectral Deterministic method to numerically solve the two–dimensional neutron transport equation in the discrete ordinates (𝑺𝑵) formulation is presented in this work. The method is based on within node general solution of the conventional one–dimensional 𝑺𝑵 transverse integrated equations considering constant approximations for the transverse leakage terms and obtaining the 𝑺𝑵 spatial balance equations. The discretized equations are solved by using a modified Source Iteration scheme without additional approximations since the average angular fluxes are computed analytically in each iteration. The numerical algorithm of the method presented here is algebraically simpler than other spectral nodal methods in the literature for the type of problems we have considered. Numerical results to two typical model problems are presented to test the accuracy of the offered method.

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  • IPEN-DOC 27716

    FIGUEIREDO, C.D.R. ; MATTAR NETO, M. . Recommendation for linearization procedure in nuclear pressure vessel-nozzle intersections. Brazilian Journal of Radiation Sciences, v. 8, n. 3A, p. 1-13, 2020. DOI: 10.15392/bjrs.v8i3A.1572

    Abstract: The pressure vessel design is a fundamental step during the construction of new pressurized water reactors (PWRs). In these facilities, several safety requirements are necessary to guarantee the protection of workers, community and environment against the release of radioactive materials. The Design by Analysis is the procedure presented in the ASME Code, Section III, for nuclear components, which consist of rigorous analysis and classification of all types of stresses and loading conditions to incorporate smaller safety factors increasing the general safety. The limits presented in the ASME Code, Section III, were based on the shell theory. However, precise rules for achieving the various stress categories, in solid finite element analysis, have not been implemented yet in the code. For this reason, this work presents a methodology for the linearization procedure of elastic stresses in pressure vessel-nozzle intersections. Therefore, a vessel was modelled in tridimensional solid finite elements, analyzed and verified as a nuclear component. Then, a discussion of how to perform the code verifications was presented, as well as a mapping of stresses. The lines that were constructed in pressure vessel between transition and structural elements in the longitudinal plane (0º) and lines in structural elements in the nozzle in the transversal plane (90º) present higher stresses and are compared with the ASME Code, Section III limits.

    Palavras-Chave: a codes; design; finite element method; mesh generation; nozzles; pressure vessels; pwr type reactors; stress analysis

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  • IPEN-DOC 27715

    BUSTILLOS, OSCAR V. . Mobilidade iônica acoplada a espectrometria de massas. Revista Analytica, v. 111, p. 21-23, 2021.

    Palavras-Chave: mass spectroscopy; ion mobility; electron capture; electron detection; isomers; drugs

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  • IPEN-DOC 27714

    BUSTILLOS, OSCAR V. . O espectro de massas na espectrometria de massas. Revista Analytica, v. 110, p. 24-26, 2021.

    Palavras-Chave: mass spectra; mass spectroscopy; ion sources; chemical analysis; electron scanning; ionization

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  • IPEN-DOC 27713

    LIMA, VERA M.F. de ; PEREIRA JUNIOR, ALFREDO; OLIVEIRA, GUILHERME L. de. The spreading depression propagation: how electrochemical patterns distort or create perception. Open Journal of Biophysics, v. 11, n. 2, p. 133-146, 2021. DOI: 10.4236/ojbiphy.2021.112003

    Abstract: At the transition from quiescence to propagating waves recorded in isolated retinas, a circular electric current closes in the extracellular matrix; this circular current creates a magnetic torus flow that, when entering quiescent tissue in front of the wave, recruits elements and when leaving behind, helps to build the absolute refractory state. The waving magnetic torus is the consequence of the vortex effect and explains the energy boost that drives propagation. Methods: We interpret experimental results from intrinsic and extrinsic fluorescence dyes, voltage, calcium and pH sensitive, optical signals from isolated retinas, and time series recordings using ion exchange resins: Ca, K, pH, Na, Cl recorded extracellularly at retinas, cerebellums and cortices coupled to spreading depression waves. Finally, we checked the ECoG activity, also a time series, at the transition from after discharges to spreading depression in rat hippocampus. Results: The integrated assessment of the diversified measurements led to the realization that the magnetic flow at the wavefront is a major contributor to the wave propagation mechanisms. This flow couples mass and charge flows as a swirling torus from excited to quiescent tissue. Conclusions: An alternative model of the brain is possible, apart from the classical HH and molecular biology model. Physical chemistry of charged gels and its flows explains the results. The conceptual framework uses far from equilibrium thermodynamics.

    Palavras-Chave: brain; electrochemistry; retina; resonance; central nervous system; vortices; vortex flow

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  • IPEN-DOC 27712

    KLUMPP, RAFAEL E. ; DONATUS, UYIME ; SILVA, REJANE M.P. da ; ANTUNES, RENATO A.; MACHADO, CARULINE de S.C. ; MILAGRE, MARIANA X. ; ARAUJO, JOAO V. de S. ; VIVEIROS, BARBARA V.G. de ; COSTA, ISOLDA . Corrosion protection of the AA2198-T8 alloy by environmentally friendly organic-inorganic sol-gel coating based on bis-1,2-(triethoxysilyl) ethane. Surface and Interface Analysis, v. 53, n. 3, p. 314-329, 2021. DOI: 10.1002/sia.6919

    Abstract: In this work, a surface coating composed of organic‐inorganic hybrid sol‐gel based on bis‐1,2‐(triethoxysilyl) (BTSE) ethane was applied on AA2198‐T8 samples, and its effect on corrosion resistance was investigated and compared with that of a chromate layer formed in a solution with hexavalent chromium ions. The corrosion resistance of BTSE coated samples was evaluated by immersion tests in sodium chloride solution (0.005 mol/L NaCl) and monitored by global electrochemical techniques such as electrochemical impedance spectroscopy (EIS) and local electrochemical techniques such as scanning vibrating electrode technique (SVET) and scanning electrochemical microscopy (SECM). The formed coating layers were characterized by X‐ray photoelectron spectroscopy (XPS). The results pointed out that the BTSE is an effective alternative coating for corrosion protection of new generation Al‐Cu‐Li alloys and could replace chromates obtained in toxic and carcinogenic CrVI containing solutions leading to improved corrosion protection.

    Palavras-Chave: corrosion; corrosion protection; surface coating; silanes; aluminium alloys; sol-gel process; hybrid systems; corrosion resistance

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  • IPEN-DOC 27711

    NUNES, MARIO A.B.S.; MATOS, BRUNO R. de ; SILVA, GLAURA G.; ITO, EDSON N.; MELO, TOMAS J.A. de; FECHINE, GUILHERMINO J.M.. Hybrids nanocomposites based on a polymer blend (linear low-density polyethylene/poly(ethylene-co-methyl acrylate) and carbonaceous fillers (graphene and carbon nanotube). Polymer Composites, v. 42, n. 2, p. 661-677, 2021. DOI: 10.1002/pc.25856

    Abstract: Interfacial or separate phase location of carbonaceous nanofillers (graphene and carbon nanotubes) in polymer blends with co-continuous phases can lead to double percolation behavior, significantly increasing rheological and electrical properties. The prediction of the morphology and the location of the nanofillers has been used as a tool to evaluate the proprieties of co-continuous polymer blends. This work aims to highlight the superior conductivity levels achieved using a low amount of carbon-based fillers, by the proper selection in a multiphase polymer matrix as a template for controlled dispersion and spatial distribution of the nanoparticles, offering a compromise between easy processability and enhanced performance. Here, two polymers (linear low-density polyethylene [LLDPE] and ethylene-co-methylacrylate [EMA]) and their cocontinuous blend (LLDPE/EMA) were loaded with nanofillers (few-layer graphene [FLG], few-walled carbon nanotube [FWCNT]) via continuous melt mixing in twin-screw extrusion, separate and simultaneously. It was observed that the addition of the nanofillers changed the co-continuity of the blend, with the probable migration of the nanofillers from the EMA (hydrophilic) phase to the LLDPE (hydrophobic) phase. Rheological percolation occurred preferentially in blends containing FWCNT and FLG/FWCNT. Electrical conductivity was observed in all compositions, with higher electrical conductivity being noticed in hybrids.

    Palavras-Chave: nanocomposites; hybridization; nanotechnology; polyethylenes; polymers; electric conductivity; carbon nanotubes; graphene

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  • IPEN-DOC 27710

    ZANINI, NATHALIA A. ; RABELO, THAIS F. ; ZAMATARO, CLAUDIA B. ; CARAMEL-JUVINO, AMANDA ; ANA, PATRICIA A.; ZEZELL, DENISE M. . Morphological, optical, and elemental analysis of dental enamel after debonding laminate veneer with Er,Cr:YSGG laser: a pilot study. Microscopy Research and Technique, v. 84, n. 3, p. 489-498, 2021. DOI: 10.1002/jemt.23605

    Abstract: Laminate veneer removal is becoming a routine procedure at the dental clinic and the use of laser can facilitate its removal. This work aimed to evaluate the morphological, elemental, and optical changes in the remaining enamel after veneer removal using Er,Cr:YSGG laser. Forty‐four enamel slabs were prepared and randomly distributed into nine experimental groups, for bonding using lithium disilicate laminates with three different luting agents (Variolink Veneer, RelyX U200, and RelyX Veneer). Then each agent was debonded using Er,Cr:YSGG laser (2.78 μm) using two different protocols:3.5 W, 48.14 J/cm2, 20 Hz non‐contact and 3.0 W, 48.14 J/cm2, 20 Hz non‐contact. The morphological, optical, and elemental analysis of enamel was performed before cementation and after laser debonding, using scanning electron microscopy (SEM), optical coherence tomography (OCT), and energy‐dispersive X‐ray spectroscopy (EDS). The level of statistical significance adopted was 5%. The EDS analysis of enamel after debonding revealed a significant increase in silane and carbon, as well as a decrease in calcium and phosphate contents. Analysis showed the presence of residual cement in most experimental groups but the morphological analysis showed alteration of the enamel's prisms only in the groups that used RelyX Veneer and Variolink Veneer cements. There was no evidence of deleterious morphological changes resulting from irradiation. However, an increase in the optical attenuation coefficient by the OCT was observed due to the presence of the remaining cement. It can be concluded that the Er,Cr:YSGG laser, in the mean powers used, is efficient for veneer removal without causing deleterious effects for the enamel.

    Palavras-Chave: dentistry; enamels; lasers; laser radiation; lithium; tomography; optical properties; coherent radiation; teeth

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  • IPEN-DOC 27709

    GODOI, C.M. ; SANTOS, M.C.L. ; SILVA, A.J. ; TAGOMORI, T.L.; RAMOS, A.S. ; SOUZA, R.F.B. de ; OLIVEIRA NETO, A. . Methane conversion to higher value‑added product and energy co‑generation using anodes OF PdCu/C in a solid electrolyte reactor: alkaline fuel cell type monitored by differential mass spectroscopy. Research on Chemical Intermediates, v. 47, n. 2, p. 743-757, 2021. DOI: 10.1007/s11164-020-04296-4

    Abstract: PdxCuy/C catalysts combinations were employed to CH4 partial oxidation in mild condition using a solid electrolyte reactor—alkaline fuel cell type. The differential mass spectroscopy on line method was used to monitor the oxidation products obtained as methanol, dimethyl ether, methyl formate and potassium formate. It was observed that as the electrical potential of the reactor increases, the generation of products decreases. The best results for conversion of methane into methanol and energy co-generation was obtained from Pd90Cu10/ C and Pd50Cu50/ C due to better H2O activation effects and adsorption site for CH4 oxidation.

    Palavras-Chave: methane; electrocatalysts; solid electrolytes; oxidation; methanol; fourier transformation; infrared spectra; mass spectroscopy

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  • IPEN-DOC 27708

    LOPES, MONICA S.; PEREIRA, DAISA L. ; MOTA, CLAUDIA C.B. de O.; AMARAL, MARCELLO M.; ZEZELL, DENISE M. ; GOMES, ANDERSON S.L.. The lingual enamel morphology and bracket shear bond strength influenced by Nd:YAG laser and aluminum oxide sandblasting preconditioning. Clinical Oral Investigations, v. 25, n. 3, p. 1151-1158, 2021. DOI: 10.1007/s00784-020-03418-x

    Abstract: Objectives This study aimed to investigate the influence of Nd:YAG laser and aluminum oxide sandblasting on the shear bond strength (SBS) of lingual brackets and to optically analyze the behavior of the enamel morphology. Materials and methods Thirty-five bovines’ incisors teeth were divided into 5 groups (n = 7), according to the surface preconditioning: G1, control group; G2, Nd:YAG laser; G3, laser + aluminum oxide sandblasting (Al2O3); G4, Al2O3; and G5, Al2O3 + laser. All groups had lingual brackets bonded and shear debonded after 72 h. SBS values were analyzed, and the enamel morphology was evaluated by optical coherence tomography (OCT) and scanning electron microscope (SEM), before and after preconditioning surface. The optical attenuation coefficient (α) analysis was obtained from OCT images. Data analysis used the ANOVA test, followed by post hoc Tukey, Kruskal Wallis, and post hoc Dunn tests (significance of 5%). Results The SBS values presented similarly among groups, but the value of α showed statistical difference (p-value = 0.0124) between G3 and G5 with the others. Optical analyses indicated a melting on the enamel that suffered laser irradiation for G2 and G5 and crystal surface disorganization for G4. Sandblasting partially removes the melting of the laser effect (G3). Conclusion The sandblasting is a dispensable step for bonding lingual brackets, and the melting of the enamel after laser irradiation does not compromise the bracket adhesive resistance. Clinical relevance The Nd:YAG laser became an interesting tool to prevent caries and decrease prevalence of white spot lesions in orthodontic treatments, without systemic effects in patients with genetic high risks of caries.

    Palavras-Chave: dentistry; lasers; teeth; enamels; aluminium oxides; oral cavity; tongue; tomography

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  • IPEN-DOC 27707

    AZEVEDO, LUCIANA C. de ; ROVANI, SUZIMARA ; SANTOS, JONNATAN J.; DIAS, DJALMA B. ; NASCIMENTO, SANDI S.; OLIVEIRA, FABIO F.; SILVA, LEONARDO G.A. ; FUNGARO, DENISE A. . Study of renewable silica powder influence in the preparation of bioplastics from corn and potato starch. Journal of Polymers and the Environment, v. 29, n. 3, p. 707-720, 2021. DOI: 10.1007/s10924-020-01911-8

    Abstract: In the present study, 0.5–1.5% silica powder, from sugarcane waste ash, was incorporated into corn and potato starch bioplastics doped with sodium silicate solution to improve the properties of elongation at break and increase the thermal resistance of the bioplastics. The starch-based bioplastics were produced by casting and characterized by color analyses, transparency, opacity apparent, humidity, thickness, tensile strength, elongation at break, FTIR, DSC, SEM, and biodegradation assay. The addition of 0.5% of silica powder improved the elongation at break of the corn starch-based bioplastics. The sample CS5-P0.5 presented the highest percentage of elongation at the break among the studied samples, increased from 59.2% (without silica powder) to 78.9% (with silica powder). For potato starch bioplastic the addition of 0.5% of silica powder did not improve elongation at break but increased the thermal resistance. Increased until 17 °C for PS5-P0.5 sample and until 11 °C for PS7.5-P0.5 sample. The bioplastics of potato starch were biodegraded in 5 days, and those of corn starch took almost 40 days. Silica powder inhibited the growth of fungi in starch bioplastics.

    Palavras-Chave: silica; powders; temperature dependence; thermal conductivity; sugar cane; ashes; silica; biodegradation; plastics

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  • IPEN-DOC 27706

    ASSIS, GABRIEL P.; GARCIA, RAFAEL H.L. ; DERENZO, SILAS; BERNARDO, ANDRE. Solid-liquid equilibrium of paracetamol in water-ethanol and water-propylene glycol mixtures. Journal of Molecular Liquids, v. 323, p. 1-13, 2021. DOI: 10.1016/j.molliq.2020.114617

    Abstract: Solubility is one of most important property to produce active pharmaceutical ingredients (APIs), beyond of being related to its bioavailability. In this context, itwas determined paracetamol solid-liquid equilibriumin temperatures from20 to 50 °C for two solvent systems:water - ethanol andwater - propylene glycol (PG), by refractometry method. The experimental results were compared with five thermodynamic models (Apelblat,Wilson, UNIQUAC, NRTL and λh) and data from the literature, showing good correlations for Apelblat and the best predictive fit for the NRTL model in both solvent mixtures. Maximum solubility values were observed in a 75% ethanol composition, this result being unusual and not the same with PG. the results of this work were compared with the literature and some references point to similar behavior. Optical microscopy and X-ray diffractionmeasurements of the solids in equilibrium with the liquid indicate that maximum solubility is not associated with a change in the crystalline structure of the solid

    Palavras-Chave: chemical preparation; drugs; solubility; ethanol; propylene; glycols; x-ray diffraction; thermodynamics

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A pesquisa no RD utiliza os recursos de busca da maioria das bases de dados. No entanto algumas dicas podem auxiliar para obter um resultado mais pertinente.

É possível efetuar a busca de um autor ou um termo em todo o RD, por meio do Buscar no Repositório , isto é, o termo solicitado será localizado em qualquer campo do RD. No entanto esse tipo de pesquisa não é recomendada a não ser que se deseje um resultado amplo e generalizado.

A pesquisa apresentará melhor resultado selecionando um dos filtros disponíveis em Navegar

Os filtros disponíveis em Navegar tais como: Coleções, Ano de publicação, Títulos, Assuntos, Autores, Revista, Tipo de publicação são autoexplicativos. O filtro, Autores IPEN apresenta uma relação com os autores vinculados ao IPEN; o ID Autor IPEN diz respeito ao número único de identificação de cada autor constante no RD e sob o qual estão agrupados todos os seus trabalhos independente das variáveis do seu nome; Tipo de acesso diz respeito à acessibilidade do documento, isto é , sujeito as leis de direitos autorais, ID RT apresenta a relação dos relatórios técnicos, restritos para consulta das comunidades indicadas.

A opção Busca avançada utiliza os conectores da lógica boleana, é o melhor recurso para combinar chaves de busca e obter documentos relevantes à sua pesquisa, utilize os filtros apresentados na caixa de seleção para refinar o resultado de busca. Pode-se adicionar vários filtros a uma mesma busca.

Exemplo:

Buscar os artigos apresentados em um evento internacional de 2015, sobre loss of coolant, do autor Maprelian.

Autor: Maprelian

Título: loss of coolant

Tipo de publicação: Texto completo de evento

Ano de publicação: 2015

Para indexação dos documentos é utilizado o Thesaurus do INIS, especializado na área nuclear e utilizado em todos os países membros da International Atomic Energy Agency – IAEA , por esse motivo, utilize os termos de busca de assunto em inglês; isto não exclui a busca livre por palavras, apenas o resultado pode não ser tão relevante ou pertinente.

95% do RD apresenta o texto completo do documento com livre acesso, para aqueles que apresentam o significa que e o documento está sujeito as leis de direitos autorais, solicita-se nesses casos contatar a Biblioteca do IPEN, bibl@ipen.br .

Ao efetuar a busca por um autor o RD apresentará uma relação de todos os trabalhos depositados no RD. No lado direito da tela são apresentados os coautores com o número de trabalhos produzidos em conjunto bem como os assuntos abordados e os respectivos anos de publicação agrupados.

O RD disponibiliza um quadro estatístico de produtividade, onde é possível visualizar o número dos trabalhos agrupados por tipo de coleção, a medida que estão sendo depositados no RD.

Na página inicial nas referências são sinalizados todos os autores IPEN, ao clicar nesse símbolo será aberta uma nova página correspondente à aquele autor – trata-se da página do pesquisador.

Na página do pesquisador, é possível verificar, as variações do nome, a relação de todos os trabalhos com texto completo bem como um quadro resumo numérico; há links para o Currículo Lattes e o Google Acadêmico ( quando esse for informado).

ATENÇÃO!

ESTE TEXTO "AJUDA" ESTÁ SUJEITO A ATUALIZAÇÕES CONSTANTES, A MEDIDA QUE NOVAS FUNCIONALIDADES E RECURSOS DE BUSCA FOREM SENDO DESENVOLVIDOS PELAS EQUIPES DA BIBLIOTECA E DA INFORMÁTICA.

O gerenciamento do Repositório está a cargo da Biblioteca do IPEN. Constam neste RI, até o presente momento 20.950 itens que tanto podem ser artigos de periódicos ou de eventos nacionais e internacionais, dissertações e teses, livros, capítulo de livros e relatórios técnicos. Para participar do RI-IPEN é necessário que pelo menos um dos autores tenha vínculo acadêmico ou funcional com o Instituto. Nesta primeira etapa de funcionamento do RI, a coleta das publicações é realizada periodicamente pela equipe da Biblioteca do IPEN, extraindo os dados das bases internacionais tais como a Web of Science, Scopus, INIS, SciElo além de verificar o Currículo Lattes. O RI-IPEN apresenta também um aspecto inovador no seu funcionamento. Por meio de metadados específicos ele está vinculado ao sistema de gerenciamento das atividades do Plano Diretor anual do IPEN (SIGEPI). Com o objetivo de fornecer dados numéricos para a elaboração dos indicadores da Produção Cientifica Institucional, disponibiliza uma tabela estatística registrando em tempo real a inserção de novos itens. Foi criado um metadado que contém um número único para cada integrante da comunidade científica do IPEN. Esse metadado se transformou em um filtro que ao ser acionado apresenta todos os trabalhos de um determinado autor independente das variáveis na forma de citação do seu nome.

A elaboração do projeto do RI do IPEN foi iniciado em novembro de 2013, colocado em operação interna em julho de 2014 e disponibilizado na Internet em junho de 2015. Utiliza o software livre Dspace, desenvolvido pelo Massachusetts Institute of Technology (MIT). Para descrição dos metadados adota o padrão Dublin Core. É compatível com o Protocolo de Arquivos Abertos (OAI) permitindo interoperabilidade com repositórios de âmbito nacional e internacional.

1. Portaria IPEN-CNEN/SP nº 387, que estabeleceu os princípios que nortearam a criação do RDI, clique aqui.


2. A experiência do Instituto de Pesquisas Energéticas e Nucleares (IPEN-CNEN/SP) na criação de um Repositório Digital Institucional – RDI, clique aqui.