Reposiório IPEN: Recent submissions

  • IPEN-DOC 28574

    MENDES, LUCAS S.; NACARATTI, DAVI P.; SAMAD, RICARDO E. ; MOTTA, CLAUDIO C.. Theoretical analysis of the efficiency of a 7 × 1 end-pumped power combiner. In: SBMO/IEEE MTT-S INTERNATIONAL MICROWAVE AND OPTOELECTRONICS CONFERENCE, October 24-27, 2021, Fortaleza, CE. Proceedings... Danvers, MA, USA: Institute of Electrical and Electronic Engineers (IEEE), 2021. DOI: 10.1109/IMOC53012.2021.9624827

    Abstract: An analytical formulation for the power transmission efficiency of a 7 × 1 end-pumped combiner has been developed and is reported in this paper. The formulation is supported by the Coupled-Mode Theory, and considers the modal coupling in a straight, circular cross section, optical fiber whose radius decreases monotonically. Within this scope, the power efficiency for each input fiber is determined for different tapers shapes.

    Palavras-Chave: optical fibers; coupling; power transmission; pumping

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  • IPEN-DOC 28573

    MELO, PEDRO B. dos S.; CARDOSO, ELBIS S.; SAMAD, RICARDO E. ; MOTTA, CLAUDIO C.. Temperature analysis of a tandem-pumping YDCFL due photodarkening. In: SBMO/IEEE MTT-S INTERNATIONAL MICROWAVE AND OPTOELECTRONICS CONFERENCE, October 24-27, 2021, Fortaleza, CE. Proceedings... Danvers, MA, USA: Institute of Electrical and Electronic Engineers (IEEE), 2021. DOI: 10.1109/IMOC53012.2021.9624919

    Abstract: A theoretical analysis was developed to present the influence of the temperature photodarkening effect on the performance of high power ytterbium doped double-clad optic fiber lasers. To support the theoretical analysis, three fundamental equations were used to describe the heat generation in the fiber core, the intrinsic light absorption, the quantum defect, and the influence of the photodarkening effect in the laser performance. With these equations in hand it was possible to investigate the behavior of the total heat flux in the fiber and the temperature distribution, both in the fiber’s core in the steady state regime. The laser model presented in this study was developed to demonstrate the fundamental importance of the photodarkening effect in the heating generation of silica fiber lasers in a tandem pumping configuration.

    Palavras-Chave: ytterbium ions; optical fibers; doped materials; photons; heat transfer

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  • IPEN-DOC 28572

    NACARATTI, DAVI P.; MENDES, LUCAS S.; SAMAD, RICARDO E. ; MOTTA, CLAUDIO C.. Optimization of Fiber Bragg Grating for sidelobe reduction of reflectivity. In: SBMO/IEEE MTT-S INTERNATIONAL MICROWAVE AND OPTOELECTRONICS CONFERENCE, October 24-27, 2021, Fortaleza, CE. Proceedings... Danvers, MA, USA: Institute of Electrical and Electronic Engineers (IEEE), 2021. DOI: 10.1109/IMOC53012.2021.9624744

    Abstract: The reflectivity spectrum of a Fiber Bragg Grating with uniform modulation of refractive index is followed by a series of sidelobes at adjacent wavelengths. An efficient method to minimize these unwanted sidelobes is to increase gradually the coupling coefficient into the grating entrance, and decrease it gradually until the grating end. It is possible to vary the amplitude of the coupling coefficient along the length using an apodization function. This paper presents the development of an analytical formulation of the grating reflectivity to analyze the sidelobe reduction dependence on the apodization function. Additionally, simulations were performed to studying the grating peak reflectivity dependence on the apodization function and grating length.

    Palavras-Chave: gratings; fibers; bragg reflection; coupling

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  • IPEN-DOC 28571

    RODRIGUES, VANESSA G. ; ERETIDES, GABRIEL T. ; RODAS, ANDREA C.D. ; CASTANHO, SONIA R.H.M. ; YAMAGATA, CHIEKO . Síntese de pós biocerâmicos dos sistemas CaO-MgO-SiO2 e SiO2-ZrO2 por sol-gel e coprecipitação / Synthesis of bioceramic powders of CaO-MgO-SiO2 and SiO2-ZrO2 systems by sol-gel and co-precipitation. In: INTERNATIONAL CONFERENCE FOR ACADEMIA AND INDUSTRY CO-OPERATION, 2nd; INTERNATIONAL MEETING IN MATERIALS SCIENCE AND ENGINEERING OF MARANHAO, 2nd, November 8-12, 2021, São Luís, MA. Proceedings... 2021. p. 1-7.

    Abstract: Neste trabalho, foram sintetizados pós biocerâmicos dos sistemas CaO-MgO-SiO2 e SiO2-ZrO2 pela combinação das técnicas sol-gel e coprecipitação. Solução Na2SiO3, um efluente de alta pureza gerado no processo de fusão alcalina da zirconita, foi empregada como fonte de SiO2, e soluções clorídricas de Mg e Cl foram utilizadas como precursoras de CaO e MgO. O pó sintetizado de composição molar 43,30% CaO, 10,72% MgO e 45,98% SiO2 apresentou as fases cristalinas wollastonita e diopsita após tratamento térmico a 550 °C por 4h. Cerâmica obtida desta mesma amostra sinterizada a 1200 °C por 2h apresentou bioatividade a partir de 7 dias de imersão em Simulated Body Fluid (SBF) e teste de citotoxicidade mostrou que a amostra não é citotóxica. Para a síntese de pó cerâmico do sistema SiO2-ZrO2 foram utilizadas soluções Na2SiO3 e ZrOCl2 provenientes do processo da fusão alcalina da zirconita como fontes de SiO2 e ZrO2. O pó sintetizado de composição molar (SiO2:ZrO2) (62:38) foi calcinado a 900°C por 3h e a fase tetragonal foi obtida. Cerâmica obtida após sinterização a 1500 °C por 2h foi submetida a teste de bioatividade e citotoxicidade. O produto não apresentou citotoxicidade e até 21 dias de imersão em SBF não apresentou bioatividade.

    Palavras-Chave: sol-gel process; coprecipitation; biological materials; ceramics; oxide minerals

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  • IPEN-DOC 28570

    MATTOS, MARCIO V.R. de; SANTOS, GIVANILDO A. dos; TERAM, ROGERIO; NASCIMENTO, MAURICIO S. ; SANTOS, VINICIUS T. dos; SILVA, MARCIO R. da; COUTO, ANTONIO A. . Obtenção das variáveis térmicas de solidificação da liga Alpaca 2 c/ Pb: Obtaining the solidification thermal parameters of Alpaca 2 c/Pb alloy. In: INTERNATIONAL CONFERENCE FOR ACADEMIA AND INDUSTRY CO-OPERATION, 2nd; INTERNATIONAL MEETING IN MATERIALS SCIENCE AND ENGINEERING OF MARANHAO, 2nd, November 8-12, 2021, São Luís, MA. Proceedings... 2021. p. 1-7. DOI: 10.29327/2ndicaic2ndimmsem2020.434554

    Abstract: O objetivo deste trabalho é determinar experimentalmente as variáveis térmicas de solidificação da liga Alpaca 2 c/ Pb obtidas após a solidificação unidirecional ascendente do lingote. A liga foi solidificada em uma lingoteira de aço inoxidável AISI 304 montada em um dispositivo de resfriamento unidirecional ascendente. O calor foi extraído direcionalmente através de refrigeração por água na chapa base fabricada em grafite. A microestrutura foi analisada por meio de microscopia óptica (MO). As variáveis térmicas de solidificação velocidade de deslocamento da isoterma liquidus (VL), taxa de resfriamento (TR) e gradiente térmico (GL) foram avaliadas em função da distância da superfície de extração de calor. Como resultado observou-se que maiores taxas de resfriamento e velocidades de deslocamento da isoterma liquidus são obtidas nas posições mais próximas da base de extração de calor.

    Palavras-Chave: ternary alloy systems; solidification; copper alloys; nickel alloys; zinc alloys; castings; thermal analysis

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  • IPEN-DOC 28569

    MARTURANO, JOSE L.M.; SANTOS, GIVANILDO A. dos; TERAM, ROGERIO; NASCIMENTO, MAURICIO S. ; SANTOS, VINICIUS T. dos; SILVA, MARCIO R. da; COUTO, ANTONIO A. . Estudo das variáveis térmicas da liga UNS C90200 / Study of thermal parameters of the UNS C90200 alloy. In: INTERNATIONAL CONFERENCE FOR ACADEMIA AND INDUSTRY CO-OPERATION, 2nd; INTERNATIONAL MEETING IN MATERIALS SCIENCE AND ENGINEERING OF MARANHAO, 2nd, November 8-12, 2021, São Luís, MA. Proceedings... 2021. p. 1-7.

    Abstract: Este trabalho tem o objetivo de analisar as variáveis térmicas da liga UNS C90200 em um processo de solidificação unidirecional ascendente. A liga foi obtida em uma lingoteira de aço inoxidável AISI 304, com base de grafite montada em um dispositivo de resfriamento unidirecional ascendente. As variáveis térmicas de solidificação velocidade de deslocamento da isoterma liquidus (VL), taxa de resfriamento (TR) e gradiente térmico (GL) foram avaliadas em função da distância da superfície de extração de calor. A microestrutura foi analisada por meio de microscopia óptica (MO). Como resultado observou-se que maiores taxas de resfriamento e velocidades de deslocamento da isoterma liquidus são obtidas nas posições mais próximas da base de extração de calor.

    Palavras-Chave: copper alloys; solidification; microstructure; thermal analysis; castings

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  • IPEN-DOC 28568

    GERAMI, ADELEH M.; SCHELL, JULIANA; CARBONARI, ARTUR ; COSTA, MESSIAS S.; COSTA, CLEIDILANE; VIEJO, CARLOS D.G.; LORENZ, KATHARINA; PIRES, JULIO; MONTEIRO, JOAO; JOHNSTON, KARL; CORREIA, JOAO M.. Density functional theory study of Cd impurities in molybdenum trioxide. In: ISOLDE WORKSHOP AND USERS MEETING, December 14-16, 2021, Online. Abstract... 2021. p. 27-28.

    Abstract: Transition metal oxides semiconductors (TMOs) are known for their special optical and electrical properties with wide-ranging applications, including gas sensing, storage devices such as Li-ion batteries, solar cells, and catalysts[1,2]. Among different types of TMOs, there is a class of materials that are distinguished by their unique layered structure and multiple oxidation states, such as MoO3, WO3, and V2O5. The molybdenum trioxide (MoO3) is known for its photo-, thermo- and electrochromism, high catalytic activity[3]. The MoO3 has found in different structural phases including the orthorhombic phase, α-MoO3; monoclinic phase, β-MoO3; metastable phase at high-pressure conditions, β′-MoO3; and hexagonal phase, h-MoO3[4]. Among them, the α-MoO3 is the most stable crystal phase and it has a layered structure consisting of van der Waals bonded sheets of distorted edge-sharing Mo−O6 octahedra in which Mo atoms are bounded by three distinct types of oxygen atoms[5]. In this research, the structural properties and hyperfine parameters of 111mCd(111Cd) impurities in α-MoO3 are investigated by first-principle calculations in the framework of density functional theory (DFT). The Perdew–Burke–Ernzerh of generalized gradient approximation (GGA-PBE), and GGA-PBE plus Hubbard-U corrections for onsite Coulomb interactions are used in the DFT calculations. In the calculations performed, the effect of van der Waals forces between layers is employed using the DFT-D3 method[6]. To interpret the experimental results, different configurations around the Cd atom including the different types of oxygen vacancies are simulated. The comparison of experimental data with calculated hyperfine parameters indicates that the Cd atom is predominantly located in the interstitial lattice site of MoO3, and also the oxygen vacancy is most likely to form on the 2-fold coordinated (O2) atoms. The results of this work demonstrate the benefit of first-principle calculations for solving the outstanding questions arising from the experiment.

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  • IPEN-DOC 28567

    BURIMOVA, ANASTASIA ; LEITE NETO, OSMAR F. ; BOSCH-SANTOS, BRIANNA ; CORREA, EDUARDO L. ; PEREIRA, LUCIANO F.D. ; SALES, TATIANE S.N. ; RIBEIRO JUNIOR, IBERE S. ; COSTA, MESSIAS S.; COSTA, CLEIDILANE; DANG, THANH T.; ZYABKIN, DMITRY; VAN STIPHOUT, KOEN K.F.; GERAMI, ADELEH M.; CORREIA, JOAO M.; SCHELL, JULIANA; CARBONARI, ARTUR W. . Cd impurities in Vanadium oxides: a hyperfine interaction investigation using 111mCd nuclei. In: ISOLDE WORKSHOP AND USERS MEETING, December 14-16, 2021, Online. Abstract... 2021. p. 15-16.

    Abstract: The number of metastable phases, the capriciousness at changing external conditions, and lack of accurate description of local behavior already resulted in severe misinterpretation of experimental outcomes for vanadium oxides[1–3]. The scope of already implemented and potential applications of vanadium oxides is, indeed, impressive, particularly as a battery cathode for energy storage[ 4]. Doping is widely exploited as a means of application-oriented tuning of the material properties. The properties of each particular phase may be tuned by doping to satisfy specific requirements and/or improve the functional performance. In the work here reported, electric quadrupole interaction on 111mCd nuclei implanted in vanadium pentaoxide doped with different concentrations of Cd were measured with time-differential perturbed angular correlations (TDPAC). Pure V2O5 as well as doped with 1%, 5%, and 10% of Cd were measured at different temperatures. To correlate the results with the possible formation of different phases and compounds, samples of VO2, CdV2O6, and Cd2V2O7 were also measured. The intention is to provide a comprehensive description, at an atomic level, of the doping effects on the local crystal structure and the electronic structure around the impurity and the consequences on the properties of the host oxides. Preliminary results show that the probability of formation of cadmium vanadates is low but the temperature and atmosphere of measurements have an important effect on the local scale.

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  • IPEN-DOC 28566

    TESSARI-ZAMPIERI, MARIA C.; SANTIAGO, ALESSANDRO F. de; LOPES, WEDER F.; SILVA, ABRAAO R. da; SCAPIN, MARCOS A. . Utilização de projetos de nanossatélites na graduação em Engenharia de Computação: planejamento do subsistema energia elétrica para CubeSat. In: WORKSHOP EM ENGENHARIA E TECNOLOGIA ESPACIAIS, 12th, 6-7, 13-14 de novembro, 2021, Online. Anais... São José dos Campos, SP: Instituto Nacional de Pesquisas Espaciais (INPE), 2021. p. 1-10.

    Abstract: Para compreender como as disciplinas de Engenharia de Computação podem ser utilizadas em situações reais de desenvolvimento de nanossatélites, foi elaborado um protótipo de subsistema de energia para CubeSat e simulador de órbita. O protótipo foi elaborado com 2 painéis solares conectados em paralelo, permitindo redundância no sistema para evitar eventuais problemas de falta de energia. O protótipo Univesp.1 apresentou uma demanda estimada de energia de1.478 mAh, para ser utilizadas durante o período de 36 min. em que estará na região de eclipse. No simulador de órbita circular foram utilizados os resultados obtidos dos dados simulados e calculados para a missão, e disponibilizado na WEB para comparação de dados de planejamento para outros pesquisadores.

    Palavras-Chave: satellites; orbits; simulators; energy management systems; computerized control systems; engineering; training; educational tools

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  • IPEN-DOC 28565

    LINS, C. ; MOREIRA, E.G. ; SOUSA, E.P.. Ecotoxicological quality of Caraguatatuba Bay sediment, São Paulo, Brazil. In: SOCIETY OF ENVIRONMENTAL TOXICOLOGY AND CHEMISTRY (SETAC) LATIN AMERICA BIENNIAL MEETING, 14th, September 26-29, 2021, Online. Abstract... Pensacola, FL, USA: Society of Environmental Toxicology and Chemistry (SETAC), 2021. p. 54-54.

    Abstract: Caraguatatuba Bay (-23.66363, -45.43035), at the northern seashore of São Paulo State, Brazil, is exposed to significant sources of marine pollution: domestic effluents and spills of oil and its derivatives. This is due to its proximity to the São Sebastião Channel, where the submarine emissary outfall takes place and where the largest oil transport terminal in Brazil is located. Due to their hydrodynamic characteristics, pollutants tend to deposit in the sediment, impacting the organisms associated with it. These organisms are of great ecological importance, linked to the basis of the food chain and many species are of nutritional and commercial interest. The region remains an important stronghold of artisanal fishermen and mollusk pickers, which raises concerns about the consumption of these organisms by the local population and tourists. The aim of this study was to evaluate the quality of the bay sediment by means of ecotoxicological tests on sediments collected at six points distributed in the bay, in the 2018 winter and in the 2019 summer. Total sediment acute toxicity tests were performed using the amphipod Leptocheirus plumulosus. Samples that presented different results compared to the control sample were only observed in the winter campaign, in three points: Indaiá and Centro Beaches, according to Dunnett's test (p ≤ 0.05) and Indaiá, Centro and Camaroeiro Beaches, according to the t-test (p ≤ 0.05). Sediment samples of these beaches showed adverse effect to the organisms of the assay, being considered toxic. Sediment samples from Porto Novo, Flexeiras and Palmeiras Beaches in winter and all points in the summer campaign did not cause adverse effects to the organisms and were not considered toxic. The three points which samples were considered toxic are on the beaches located from the center to the northern end of the bay where an inlet is formed. The distribution of points with toxicity follows the pattern of particle deposition and approaches the results of sanitary quality of the region according to CETESB, the São Paulo State Environmental Protection Agency.

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  • IPEN-DOC 28564

    TOMINAGA, F. ; LEO, P.; BORRELY, S.I. . Toxicity assessment of acetylsalicylic acid using Saccharomyces cerevisiae. In: SOCIETY OF ENVIRONMENTAL TOXICOLOGY AND CHEMISTRY (SETAC) LATIN AMERICA BIENNIAL MEETING, 14th, September 26-29, 2021, Online. Abstract... Pensacola, FL, USA: Society of Environmental Toxicology and Chemistry (SETAC), 2021. p. 50-50.

    Abstract: Urban and industrial growth has triggered the release of toxic compounds into the environment, causing negative impacts on the population and ecosystems. Among the pollutants, pharmaceuticals have drawn attention due to potential of impacting the environment at ecological relevant concentrations. Aspirin is widely used in human medicine as an analgesic, antipyretic and in actively preventing platelet aggregation, and it is frequently detected in influent samples at relatively high concentrations. The yeast Saccharomyces cerevisiae consists in simple eukaryotic model, widely used for toxicity assessment. The current study aims to evaluate the toxicity of the anti-inflammatory acetylsalicylic acid (aspirin) using viability and conductometric assays. The viability assays were based on the evaluation of the number of viable cells present in a cell suspension after 1 hour exposure, while the conductometric tests were done by monitoring of changes in the specific conductivity of suspensions of S. cerevisiae due to inhibition of fermentation in toxic conditions after 30 minutes of exposure. The viability tests showed no reduction of viability at the evaluated concentrations (up to 100 mg L-1). The conductometric assays demonstrated low sensibility of the yeast to aspirin with EC5030min of 815 mg L-1. The results also indicated that there was no increase in the sensitivity of conductometric assays even at 6 hours of exposure. Furthermore, the acute toxicity data was compared with data obtained from in silico toxicity models (ECOSAR). Toxicity data collated from the software from different trophic levels showed EC5096h, LC5048h and LC96h of 867, 1774 and 777 mg L-1 for green algae, daphnid and fish, respectively, indicating low toxicity of aspirin.

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  • IPEN-DOC 28563

    FERREIRA, LUCAS A. dos S. ; MUCCILLO, ELIANA N. dos S. . Electrical conductivity and grain growth of 12Ce-TZP. In: BRAZIL MRS MEETING, 19th; INTERNATIONAL UNION OF MATERIALS RESEARCH SOCIETIES - INTERNATIONAL CONFERENCE ON ELECTRONIC MATERIALS, August 30 - September 3, 2021, Online. Abstract... São Carlos, SP: Aptor Software, 2021. p. 45-45.

    Abstract: Ceramic materials based on tetragonal zirconia polycrystals (TZP) with yttrium or cerium oxide have been thoroughly studied for a number of technological applications, due to their outstanding thermomechanical properties. In this work, tetragonal zirconia polycrystals containing 12 mol% cerium oxide (12Ce-TZP) were prepared by solid-state reaction using different sintering methods, to evaluate the influence of the final microstructure on the electrical conductivity. High purity zirconium oxide and cerium oxide starting chemicals were weighted in the stoichiometric proportion and ball-milled for 6 h for homogenization. Cylindrical specimens were prepared by pressing followed by sintering. Sintering experiments were carried out by the conventional and the two-stage methods. The mean grain size of specimens sintered by the conventional method achieved approximately 2.4 mm after sintering at 1450 ºC/5 h, whereas those sintered by the two-stage method exhibit less than 1.5 mm even after 10 h at 1350 ºC, in the second stage of sintering. The electrical conductivity determined by impedance spectroscopy shows the usual Arrhenius behavior for both the bulk (or intragrain) and grain boundary (intergrain) conductivities, with activation energies of ~0.97 (bulk) and 1.25 eV (grain boundary). The grain conductivity of specimens sintered by different methods does not depend on the grain size. In contrast, the grain boundary conductivity is higher for specimens sintered by the two-stage method, possibly due to dissolution of minor impurities located at grain boundaries into the bulk, during the long holding times of the two-stage method.

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  • IPEN-DOC 28562

    SILVA, JOSE T. da ; SOUZA, CARLA D. de ; NOGUEIRA, BEATRIZ R. ; ANGELOCCI, LUCAS V. ; ZEITUNI, CARLOS A. ; ROSTELATO, MARIA E.C.M. . Homogeneity evaluation of phosphorus-32 epoxy plaques to be used in the treatment of spinal and intracranial cancer by brachytherapy. In: BRAZIL MRS MEETING, 19th; INTERNATIONAL UNION OF MATERIALS RESEARCH SOCIETIES - INTERNATIONAL CONFERENCE ON ELECTRONIC MATERIALS, August 30 - September 3, 2021, Online. Abstract... São Carlos, SP: Aptor Software, 2021. p. 919-919.

    Abstract: In Brachytherapy, radioactive source is positioned close to the tumor. The most important advantage is that the target region receives most of the dose, protecting the healthy tissues adjacent to the tumor region. In order to use these sources, a high dosimetric uniformity must be achieved, so a homogeneous dose delivery can be delivered to the target. In the present work, the consistency of the epoxy resin plate was evaluated using a methodology developed in the laboratory for the production of radiotherapy sources at IPEN / CNEN - SP. Several tests were carried out to determine the best mold for the source manufacture. It was concluded that polytetrafluoroethylene (PTFE), which is commercially known as teflon, obtained the best result, due to the ease unmold of the source after the resin curing process. The epoxy plaques were produced with resin 2220 and catalyst 3154 (Avipol), at a 2:1 mass ratio. To simulate the radioactive material, hydrochloric acid (HCl) equivalent to 5% of the total mass (resin + catalyst) is added. The epoxy resin cured for 24 h at room temperature. The thickness of the plaques was measured reaching an average value of 0.300 mm ± 0.070. The measurements were made with a micrometer, measuring 10 points of each plaque. The measures of width and length were not performed, as these parameters do not influence the uniformity of the dose. In order for the distribution of phosphorus-32 activity to be stipulated, a Monte Carlo Simulation using the MCNP code was performed. The maximum dose variation along the plaque, considering a totally uniform thickness of 0.300 mm, resulted in <0.5% up to 0.5 cm before the edge. The result of the simulation shows that with a uniformly thick plaque, the dose distribution trend is homogeneous. Based on the results, the epoxy polymer plaques are shown to be viable for use in brachytherapy, and the next step of the work will be the tests with radioactive material.

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  • IPEN-DOC 28561

    TRINDADE, FABIANE J.; DAMASCENO, SERGIO; OTUBO, LARISSA ; SCHMAL, MARTIN; FLORIO, DANIEL Z. de; FONSECA, FABIO C. ; FERLAUTO, ANDRE S.. Lanthanum doped ceria shaped nanostructures for oxidative coupling of methane. In: BRAZIL MRS MEETING, 19th; INTERNATIONAL UNION OF MATERIALS RESEARCH SOCIETIES - INTERNATIONAL CONFERENCE ON ELECTRONIC MATERIALS, August 30 - September 3, 2021, Online. Abstract... São Carlos, SP: Aptor Software, 2021. p. 308-308.

    Abstract: The abundance of natural gas due to the advancements in exploration and extraction technologies has increased the interest in the direct conversion of methane to C2 molecules via oxidative coupling of methane (OCM) reactions [1]. The design of catalysts by tailoring shape and oxygen vacancies has a significant impact on their performance [2]. Within this context, in this work, the fine-tuning of structural defects of ceria rod-like and cube-like shaped nanoparticles were performed via La3+ doping (LaxCe1-xO2-x/2) in molar ratios of x=5-90 mol %. The morphology control was achieved by varying the hydrothermal synthesis temperature from 110 °C to 180 °C. The characterization of LaxCe1-xO2-1/2 catalysts was performed by SEM, HRTEM, XRD, and Raman spectroscopy. The catalytic performance of the new nanomaterials for the OCM reaction was studied at 750 °C with an in-line gas chromatograph. In the LaxCe1-xO2-x/2 nanorods, the fluorite crystalline structure is essentially maintained even for x = 0.6. The Raman spectra analysis indicates that the addition of La3+ leads and increases the formation of different amounts of extrinsic and intrinsic oxygen vacancies. In addition, the catalytic tests for OCM reaction show that the LaxCe1- xO2-1/2 (x=50%) nanorods catalyst have 25% of CH4 conversion and 48% of selectivity for C2 products. The concentration of reactive oxygen species in the LaxCe1-xO2-1/2 (x=50%) nanorods was crucial to improving the conversion rates and selectivity.

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  • IPEN-DOC 28560

    CARVALHO, SABRINA G. de M. ; MUCCILLO, ELIANA N. dos S. ; MUCCILLO, REGINALDO . Ionic conductivity of electric field-assisted sintered gadolinia-doped ceria/alkali salts membranes. In: BRAZIL MRS MEETING, 19th; INTERNATIONAL UNION OF MATERIALS RESEARCH SOCIETIES - INTERNATIONAL CONFERENCE ON ELECTRONIC MATERIALS, August 30 - September 3, 2021, Online. Abstract... São Carlos, SP: Aptor Software, 2021. p. 299-299.

    Abstract: Ceramic-carbonate dual-phase membranes were prepared according to the usual procedure: by vacuum impregnation of molten sodium-lithium carbonates (NLC) into sintered porous ceria-20 mol% gadolinia (20GDC) solid electrolyte cylindrical pellets; and also by flash sintering samples with 75 wt.% (CeO2: 20 mol% Gd2O3) and 25 wt.% NLC. Sintering was accomplished by applying 200 V cm-1 to the membrane positioned in a sample holder of a dilatometer for monitoring thickness shrinkage, limiting the electrical current to 1 A. Electrochemical impedance spectroscopy measurements were performed in the 5 Hz-13 MHz frequency range from 300ºC to 600ºC in composite ceramic membranes, covering the solid-to-molten NLC temperature range. Analysis of the impedance diagrams allowed for the evaluation of the oxide ion and carbon dioxide ion conductivities. The Arrhenius plots showed the transition from oxide ion conduction (due to the solid electrolyte) to carbonate ion conduction (due to the molten NLC). The ionic conductivity values of membranes flash sintered at 420ºC in 2 min were higher than those of conventionally sintered membranes and similar to reported values of membranes sintered at 690ºC for 2 h.

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  • IPEN-DOC 28559

    DIAZ, JULIO C.C.A. ; MUCCILLO, REGINALDO . Impedance spectroscopy analysis of flash sintered zirconia: 8 mol% yttria solid electrolytes with alkali halide addition. In: BRAZIL MRS MEETING, 19th; INTERNATIONAL UNION OF MATERIALS RESEARCH SOCIETIES - INTERNATIONAL CONFERENCE ON ELECTRONIC MATERIALS, August 30 - September 3, 2021, Online. Abstract... São Carlos, SP: Aptor Software, 2021. p. 298-298.

    Abstract: Electrical properties of porous ZrO2:8 mol% Y2O3 ceramics with LiF sintering aid were studied. The specimens were sintered by transient liquid phase formation under the application at 650ºC of 200 V cm-1 AC electric field for various current density, current elapsed time, and lithium fluoride content. Low electric current densities coupled with long application times produced homogeneous specimens. Variations in the electric current density and current elapsed time allowed to obtain sample densification in the 60%-75% range. Impedance spectroscopy measurements were carried out to estimate the relative pore content, evaluating the product of the blocking factor αR (=Rg/(Rg +Rgb), R, g and gb stand for resistance, grain and grain boundary, respectively) to the frequency factor αf (= fgb/fg, f is the characteristic frequency), which is proportional to the blocker volume, i.e., the porosity. A direct correspondence between αR•αf and the apparent porosity, obtained after determining the apparent density by the Archimedes method, was observed.

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  • IPEN-DOC 28558

    PELOSI, ANDRE G.; SANTOS, SABRINA N.C. dos; DIPOLD, JESSICA ; ANDRADE, MARCELO B. de; HERNANDES, ANTONIO C.; ALMEIDA, JULIANA M.P. de; MENDONCA, CLEBER R.. Investigation of the influence of transition metal ions in niobium-borotellurite glasses through vibrational and nonlinear optical spectroscopy. In: BRAZIL MRS MEETING, 19th; INTERNATIONAL UNION OF MATERIALS RESEARCH SOCIETIES - INTERNATIONAL CONFERENCE ON ELECTRONIC MATERIALS, August 30 - September 3, 2021, Online. Abstract... São Carlos, SP: Aptor Software, 2021. p. 176-176.

    Abstract: Tellurite glasses are know as good candidates to photonic devices’ production because they exhibit third-order nonlinear optical susceptibilities larger than conventional silicate and borate glasses. In addition, for glass materials such nonlinearity can be increased by adding transition or heavy metal ions. In this direction, this work analyzed the influence of Ta5+ and Zr2+ on the physical, structures, and nonlinear optical properties of niobium-borotellurite (TBN) glasses. The samples were synthesized by the melt-quench technique using a melting temperature of around 1000 ºC. DSC measurements were performed to obtain the glass transition temperature. The densities were determined by the Archimedes method. To analyze the local structure of the samples FTIR and Raman spectroscopies were used . The spectrum of nonlinear refractive index (n2) for the TBN glass doped with Ta5+ and Zr2+ ions was measured using the tunable femtosecond Z-scan technique [1]. Such results were compared with the BGO model, which involves empirical relations between the linear and nonlinear refractive index. The addition of metal transition ions did not lead to meaningful changes in the glass transition temperatures (Tg). The formation of non-bridging oxygen and BO3 units was observed from the structural analysis. The n2 value determined indicates that the nonlinear optical responses are associated with the glass matrix. The structural changes caused by the addition of Ta5+ and Zr2+ demonstrated a decrease followed by an increase in the value of the molar electronic polarization of the samples, respectively.

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  • IPEN-DOC 28557

    DENALDI, RAFAEL L. ; MUCCILLO, REGINALDO . High temperature percolation of carbonate ions through porous alumina and zirconia-magnesia impregnated with alkali carbonates. In: BRAZIL MRS MEETING, 19th; INTERNATIONAL UNION OF MATERIALS RESEARCH SOCIETIES - INTERNATIONAL CONFERENCE ON ELECTRONIC MATERIALS, August 30 - September 3, 2021, Online. Abstract... São Carlos, SP: Aptor Software, 2021. p. 305-305.

    Abstract: Na2CO3-K2CO3 (56-44 wt.%) eutectic composition was vacuum-impregnated into porous Al2O3 (alumina) and to ZrO2: 3 wt.% MgO (magnesium-partially stabilized zirconia, Mg-PSZ) at the molten eutectic temperature. Porosity was achieved in the two compounds by addition and thermal removal of the eutectic composition before impregnation. The parallel surfaces of disk-shaped impregnated compositions were observed in a scanning electron microscope. The CO3 2- carbonate ion conductivity of the two composite ceramics was measured by electrochemical impedance spectroscopy in the 5 Hz-13 MHz frequency range from 470ºC to 780ºC. The permeation of the carbonate ions via eutectic composition through the ceramic membranes was ascertained by the threshold temperatures of the onset of the carbonate ion percolation: 660ºC and 720ºC for alumina and Mg-PSZ, respectively.

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  • IPEN-DOC 28556

    SOUZA, JULIANA P. de; SERNA, JILDER D.P.; MORAES, LETICIA P.R. de ; SILVA, JULIO C.M.; ALVES, ODIVALDO C.. Structural and magnetic properties of CeO2 nanomaterials as a function of different morphologies: nanocube, nanowire and nanobelt. In: BRAZIL MRS MEETING, 19th; INTERNATIONAL UNION OF MATERIALS RESEARCH SOCIETIES - INTERNATIONAL CONFERENCE ON ELECTRONIC MATERIALS, August 30 - September 3, 2021, Online. Abstract... São Carlos, SP: Aptor Software, 2021. p. 128-128.

    Abstract: The nanomaterials of cerium oxide can be applied in catalysts, fuel cells and spintronics [1]. Additionally, in its crystalline structure, small defects named oxygen gaps appear, caused by its high potential pattern of reduction from Ce IV to Ce III or that it becomes an oxidizing agent and the conferring agent. In this work we investigated the magnetic properties of three ceria morphologies on a nanometric scale: nanocubes, nanowires and nanobelt that were synthesized using the hydrothermal method. As samples prepared from studies by using X-ray diffraction (XRD), transmission electron microscopy (TEM), magnetometry (VSM) and paramagnetic resonance (EPR). XRD measurements show characteristic peaks of ceria fluorite face-centered cubic structure. Measurements of magnetization in function of the field applied at room temperature showing the ferromagnetic character with different values of the coercive field and saturation magnetization, we observe an increase in the coercive field and saturation magnetization in ceria nanocubes that can be explained by an increase in the density of vacancy [2]. The zero field cooled (ZFC) and field cooled (FC) magnetization curves measured on low magnetic fields show a soft maximum around 60 K attributed to oxygen at the sample surface. Applying to the Curie-Weiss equation indicates the presence of antiferromagnetic interactions mainly in nanobelt and nanocubes morphologies. The EPR spectra at room temperature show two paramagnetic symmetry, with axial symmetry with g1 = 1.97 and g2 = 1.94 associated with Ce 3+ and another isotropic around g = 2.03 due to vacancies of isolated oxygen for all samples. The ferromagnetic arrangement characterized by the presence of broad signals at about 3500 G is also observed in nanobelt morphologies.

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  • IPEN-DOC 28555

    ALVES, ANDRESSA A.; QUEIROZ, ÁLVARO A.A. de ; QUEIROZ, ALFREDO A.A.E. de. Fabrication of hyperbranched polyglycerols microcapsules from microfluidics guided by artificial neural networks. In: BRAZIL MRS MEETING, 19th; INTERNATIONAL UNION OF MATERIALS RESEARCH SOCIETIES - INTERNATIONAL CONFERENCE ON ELECTRONIC MATERIALS, August 30 - September 3, 2021, Online. Abstract... São Carlos, SP: Aptor Software, 2021. p. 854-854.

    Abstract: In recent years, the microfluidic approach has received a lot of attention from the scientific community due to the simple and efficient synthesis of highly monodisperse microcapsules used in a variety of applications in biotechnology and medicine such as, for example, materials synthesis, drug encapsulation, among others [1,2]. Thus, in this work, hyperbranched polyglycerol microcapsules (HPGM) were developed using microfluidic technology. Artificial neural network (ANN) feed-forward using multilayer perceptron architecture was trained and applied to model and predict the microfluidic process. The HPGM produced were characterized by scanning electron microscope (SEM), attenuated total reflection-Fourier transform infrared (ATR-FTIR) and thermogravimetric analysis (TGA). The fabricated HPGM showed spherical size and monomodal distribution with an average diameter of 29 μm. The developed ANN proved to be efficient predictor, showing well agreement with the experimental data (R2=0.9983). Based on these results in this research, it was found that the microfluidic device for producing HPGM was successfully developed since it was possible to synthesize microcapsules with targeted properties, monodispersed with high stability and low porosity. In this way, microfluidic technology guided by ANN can be used to synthesize HPGM for biotechnology processes.

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  • IPEN-DOC 28554

    PORFÍRIO, TATIANE C. ; MUCCILLO, ELIANA N. dos S. ; MUCCILLO, REGINALDO . Electric field-assisted synthesis/sintering cerium oxide: 5 wt.% gadolinium oxide. In: BRAZIL MRS MEETING, 19th; INTERNATIONAL UNION OF MATERIALS RESEARCH SOCIETIES - INTERNATIONAL CONFERENCE ON ELECTRONIC MATERIALS, August 30 - September 3, 2021, Online. Abstract... São Carlos, SP: Aptor Software, 2021. p. 321-321.

    Abstract: Gadolinium oxide ceramic powders were mixed to cerium oxide ceramic powders, pressed to pellets, and sintered either at 1450ºC for 4 h or applying 200 V cm-1 electric field at 800ºC, 900ºC and 1000ºC. The structural phases and the microstructure of the sintered pellets were analyzed by X-ray diffraction and scanning electron microscopy, respectively. The formation of substitutional solid solution was followed by monitoring the increase of the electrical conductivity by impedance spectroscopy measurements and the X-ray diffraction patterns. The main results show that Joule heating due to the flow through the pellets of the electric current, which was produced by the application of the electric field, allows for promoting partial solid solution as well as partial sintering the ceria-gadolinia pellets. Moreover, grain growth that occurred in the high temperature sintered pellets was inhibited in the electric field-assisted synthesized/sintered pellets, being an alternative technique for producing cerium oxide-gadolinium oxide solid solutions.

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  • IPEN-DOC 28553

    LANDGRAF, FERNANDO J.G.; MORAIS, WILLY A. de; GUZMAN, JHOAN; MARTORANO, MARCELO; NOBRE, RAFAEL de M.; NEVES, MAURICIO M. das . Effects of laser power and speed on keyhole formation during additive manufacturing by laser-powder bed fusion. In: BRAZIL MRS MEETING, 19th; INTERNATIONAL UNION OF MATERIALS RESEARCH SOCIETIES - INTERNATIONAL CONFERENCE ON ELECTRONIC MATERIALS, August 30 - September 3, 2021, Online. Abstract... São Carlos, SP: Aptor Software, 2021. p. 656-656.

    Abstract: Unique microstructures are generated by the laser powder bed fusion (L-PBF) process of additive manufacturing. The moving molten metal pool created by the laser beam leaves a metallographic evidence, here called melt pool profile. The melt pool profile is easily identified in many alloys owing to the severe segregation at the beginning of the epitaxial cellular solidification, on the border of the remelted zone. The resulting microstructure is associated with the laser scanning strategy used in building the piece. Twenty-four different conditions of laser beam speed and power were adopted for a bed of plasma atomized powder of a Nb-48% Ti alloy. Width and depth of the melt pool profiles in the top layer of all samples were analyzed by optical microscopy. For lower energy densities and faster laser scanning speeds, the shape of the melt pool profile is nearly parabolic. When the speed decreases, within a certain limit dependent on the laser power, the shape changes to a characteristic keyhole-type profile, with a larger depth to width ratio. The keyhole profile is due to the presence of a wide, shallow parabolic pool and a narrow and deep pool formed by a transient evaporation cavity. The experimental results are compared to the available literature.

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  • IPEN-DOC 28552

    FRANCISCO, LEONARDO H.C. ; MOREIRA, RENAN P. ; SALVADOR, FRANCINE F. da S. ; MOTTA, MARCIO P. ; FELINTO, MARIA C.F. da C. ; BRITO, HERMI F.. Near-infrared emitting Cr(3+)-doped mixed oxide luminescent materials for optical imaging. In: BRAZIL MRS MEETING, 19th; INTERNATIONAL UNION OF MATERIALS RESEARCH SOCIETIES - INTERNATIONAL CONFERENCE ON ELECTRONIC MATERIALS, August 30 - September 3, 2021, Online. Abstract... São Carlos, SP: Aptor Software, 2021. p. 194-194.

    Abstract: The rapid growth of optical imaging in the latest years proposes novel alternatives to well-established imaging techniques, in a way that current research interest within this field is now focused on the design of efficient photonic materials and optical sensors[1-2]. In this scenario, this work presents the development of Cr3+-doped Zn/Mg/Sn mixed oxides prepared via solid-state and microwave synthesis, exhibiting interesting spectroscopic properties in the red to near-infrared (NIR) range. Prepared compounds were analyzed by PXRD, where the obtained diffraction profiles followed mainly the overlapping Mg2SnO4 and Zn2SnO4 patterns, and crystallite size was estimated to be about 70 nm. SEM/EDS analysis revealed micrometer-sized particles up to 20 μm, but much smaller particles and homogeneous Cr3+ distribution were also observed. Moreover, Synchrotron radiation measurements obtained at the Brazilian Synchrotron Light Laboratory, on the TGM beamline via Vacuum UV Spectroscopy within the 4.5–7.5 eV energy range revealed distinct emission profiles with increasing Zn concentration, affecting the contribution of deep-red and NIR vibronic sidebands at 700 and 720 nm, respectively. Still, maximum absorption energies (about 6.6 eV) remained constant for all the analyzed compounds, whereas the broad-band NIR emission of Cr3+ ion centered around 770 nm assigned to the [4T2(t2e)→4A2] transition is predominant. Persistent luminescence decay curves under near-band gap excitation were also probed. Thus, in this work, we demonstrated an effective way to assemble NIR emitting luminescent materials with potential applications in optical imaging and photonics, where similar and expensive Cr3+-doped gallates are already widely explored.

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  • IPEN-DOC 28551

    GARCEZ, AGUINALDO S. ; RIBEIRO, MARTHA S. . Aplicações clínicas do laser na odontologia. Barueri, SP: Manole, 2021. 436 p.

    Palavras-Chave: dentistry; teeth; oral cavity; bone tissues; surgery; lasers; epidemiology; health hazards; control

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  • IPEN-DOC 28550

    RIBEIRO, MARTHA S. . Uso da luz na clínica odontológica para controle de contaminação. In: NUNEZ, SILVIA C. (Org.); GARCEZ, AGUINALDO S. (Org.); RIBEIRO, MARTHA S. (Org.). Aplicações clínicas do laser na odontologia. Barueri, SP: Manole, 2021. p. 424-431, cap. 18.

    Palavras-Chave: visible radiation; light sources; dentistry; coronaviruses; infectious diseases; lasers; diode tubes; oral cavity; ultraviolet radiation

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  • IPEN-DOC 28549

    RIBEIRO, MARTHA S. ; BARROS, LAYSA da C.; FERNANDES, MARCELLA R.U.; SIMONATO, LUCIANA E.; GARCEZ, AGUINALDO S. . Diagnóstico óptico em odontologia. In: NUNEZ, SILVIA C. (Org.); GARCEZ, AGUINALDO S. (Org.); RIBEIRO, MARTHA S. (Org.). Aplicações clínicas do laser na odontologia. Barueri, SP: Manole, 2021. p. 407-423, cap. 17.

    Palavras-Chave: dentistry; optical systems; laser radiation; doppler effect; flowmeters; tomography

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  • IPEN-DOC 28548

    SUZUKI, SELLY S.; STORTO, CAMILA J.; FERNANDES, MARCELLA R.U.; FUJII, DENISE N.; GARCEZ, AGUINALDO S. . Ortodontia. In: NUNEZ, SILVIA C. (Org.); GARCEZ, AGUINALDO S. (Org.); RIBEIRO, MARTHA S. (Org.). Aplicações clínicas do laser na odontologia. Barueri, SP: Manole, 2021. p. 179-205, cap. 8.

    Palavras-Chave: dentistry; teeth; bone tissues; biological regeneration; light emitting diodes; lasers

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  • IPEN-DOC 28547

    GARCEZ, AGUINALDO S. ; GOUW-SOARES, SHEILA C.. Endodontia. In: NUNEZ, SILVIA C. (Org.); GARCEZ, AGUINALDO S. (Org.); RIBEIRO, MARTHA S. (Org.). Aplicações clínicas do laser na odontologia. Barueri, SP: Manole, 2021. p. 157-178, cap. 7.

    Palavras-Chave: dentistry; infectious diseases; lasers; teeth; dentin

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  • IPEN-DOC 28546

    LAGO, ANDREA N.; MARQUES, DANIELE M.C.; GONCALVES, LETICIA M.; FERNANDES, MARCELLA R.U.; GARCEZ, AGUINALDO S. . Lasers de diodo de alta potência para cirurgia de tecidos moles: gengivoplastia. In: NUNEZ, SILVIA C. (Org.); GARCEZ, AGUINALDO S. (Org.); RIBEIRO, MARTHA S. (Org.). Aplicações clínicas do laser na odontologia. Barueri, SP: Manole, 2021. p. 79-98, cap. 3.

    Palavras-Chave: dentistry; lasers; semiconductor lasers; laser radiation; neodymium lasers; oral cavity; oral cavity

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  • IPEN-DOC 28545

    VIEIRA, RODRIGO R.; SOUSA, IASCHCARA G.L. de; OLIVEIRA, EDUARDO M. de; GARCEZ, AGUINALDO S. . Cirurgia. In: NUNEZ, SILVIA C. (Org.); GARCEZ, AGUINALDO S. (Org.); RIBEIRO, MARTHA S. (Org.). Aplicações clínicas do laser na odontologia. Barueri, SP: Manole, 2021. p. 18-78, cap. 2.

    Palavras-Chave: dentistry; lasers; surgery; solid state lasers

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  • IPEN-DOC 28544

    RIBEIRO, MARTHA S. . Princípios do uso de lasers na odontologia. In: NUNEZ, SILVIA C. (Org.); GARCEZ, AGUINALDO S. (Org.); RIBEIRO, MARTHA S. (Org.). Aplicações clínicas do laser na odontologia. Barueri, SP: Manole, 2021. p. 1-17, cap. 1.

    Palavras-Chave: dentistry; lasers; phototherapy; light emitting diodes

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  • IPEN-DOC 28543

    LEVY, DENISE . Investigando as Aplicações da Radioatividade: Curiosidades sobre diferentes áreas de atuação para inspirar professores e jovens pesquisadores. São Paulo, SP: Recanto das Letras, 2021. 164 p.

    Palavras-Chave: atomic physics; nuclear energy; fundamental interactions; radioactivity; radioactive materials; radiation protection; isotope applications; agriculture; cultural resources; food processing; irradiation

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  • IPEN-DOC 28542

    VILLAVICENCIO, ANNA L. . Irradiação de alimentos. In: KHOURY, HELEN J. (Org.); LEVY, DENISE (Org.). Investigando as aplicações da radiotividade. São Paulo, SP: Recanto das Letras, 2021. p. 137-162, cap. 6.

    Palavras-Chave: food; food processing; irradiation; food industry; regulations

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  • IPEN-DOC 28541

    GONCALVES, JANETE G. ; SORDI, GIAN . Proteção radiológica. In: KHOURY, HELEN J. (Org.); LEVY, DENISE (Org.). Investigando as aplicações da radiotividade. São Paulo, SP: Recanto das Letras, 2021. p. 89-118, cap. 4.

    Palavras-Chave: radiation protection; ionizing radiations; radiation doses; radiation effects

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  • IPEN-DOC 28540

    LEVY, DENISE . Breve história da Física Atômica e Nuclear. In: KHOURY, HELEN J. (Org.); LEVY, DENISE (Org.). Investigando as aplicações da radiotividade. São Paulo, SP: Recanto das Letras, 2021. p. 15-38, cap. 1.

    Palavras-Chave: nuclear energy; historical aspects; radioactivity; scientific personnel; nuclear physics; nuclear theory; atoms

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  • IPEN-DOC 28539

    NUNEZ, SILVIA C.; RIBEIRO, MARTHA S. . Princípios básicos da terapia fotodinâmica. In: LAGO, ANDREA D.N. (Ed.). Laser na odontologia: conceitos e aplicações clínicas. São Luís, MA: EDUFMA, 2021. p. 143-155, cap. 9.

    Palavras-Chave: photodynamic therapy; photosensitivity; light emitting diodes; therapeutic uses; dentistry

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  • IPEN-DOC 28538

    GALEGO, EGUIBERTO ; SERNA, MARILENE M. ; TATEI, TATIANE Y. ; LIMA, BRUNA R. de ; FARIA JUNIOR, RUBENS N. de . Rota ecologia para sintese de eletrodo nanoestruturado de ZnO para supercapacitor. In: NOBRE, MARCOS A. de L. (Org.). The Great World of Nanotechnology. Curitiba, PR: Artemis, 2021. p. 197-211, v. 2, cap. 15. DOI: 10.37572/EdArt_30062136115

    Abstract: Capacitores de dupla camada elétrica (EDLC) tem sido amplamente pesquisados devido as suas várias aplicações em dispositivos elétricos e eletrônicos, devido a alta densidade de potência e número de ciclos de carga e descarga. O oxido de zinco é um candidato promissor para emprego em eletrodos de supercapacitores. O ZnO é usado largamente em eletrodos de baterias com uma densidade de energia de cerca de 650 A g-1, mas tem a desvantagem de apresentar formação de dendritas devido a ciclagem constante, as quais reduzem a vida útil. Neste trabalho, reportamos um método relativamente simples, ecológico e de baixo custo para preparar eletrodos de ZnO que consiste em duas etapas. Inicia-se com a deposição de uma camada semente pelo método das deposição de camadas iônicas adsorvida e por reação sucessivamente (SILAR). Subsequentemente, a deposição em banho químico (CBD) foi usada para crescimento de nanoestruturas de ZnO. O método SILAR foi usado neste trabalho em substituição a métodos que utilizam alta temperatura e alto vácuo, tal como a deposição por vapor químico, para criar uma interface entre o coletor condutivo de aço inoxidável ou alumínio e o filme nanoestruturado de ZnO. A microscopia eletrônica de varredura ou empregada para caracterização morfológica dos eletrodos. A performance eletroquímica dos eletrodos nanoestruturados foi investigada por voltametria cíclica. A capacitância dos capacitores simétricos foi medida pelo método da carga descarga. O uso de diferentes complexantes resultou na formação de nanoestruturas com diferentes morfologias. Os voltamogramas mostraram bandas características de reações faradaícas, próprias de pseudocapacitores. Os resultados de capacitância indicam mostram que os fatores de maior influência para a capacitância foram a massa depositada e a morfologia da nanoestrutura de ZnO.

    Palavras-Chave: capacitors; energy storage; capacitive energy storage equipment; nanostructures; zinc oxides; chemical reactions; adsorption; layers

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  • IPEN-DOC 28537

    GALEGO, EGUIBERTO ; SERNA, MARILENE M. ; RAMANATHAN, LALGUDI V. ; FARIA JUNIOR, RUBENS N. de . Morfologia de filmes finos nanoestruturados de ZnO produzidos pelo método SILAR. In: NOBRE, MARCOS A. de L. (Org.). The Great World of Nanotechnology. Curitiba, PR: Artemis, 2021. p. 212-227, v. 2, cap. 16. DOI: 10.37572/EdArt_30062136116

    Abstract: A utilização do ZnO no campo da nanotecnologia é ampla devido a características físicas únicas tais como, banda proibida (~3,37 eV), energia de ligação de éxciton de 60 MeV, atóxico e de baixo custo. A estrutura cristalina hexagonal permite obter uma ampla diversidade de morfologias e isto permite sua utilização em: lasers de UV, cristais piezoeléctricos, sensores químicos, sensores de gás, diodos emissores de luz, foto detectores e células solares. Uma das possíveis morfologia do filme fino de ZnO é um arranjo unidimensional submicrométrico de bastões, nanobastões e nanofios, o qual tem atraído muito interesse devido a alta área superficial e a alta proporção de aspecto, que são nanopartículas com um comprimento muitas vezes maior do que sua largura. Neste trabalho foi estudada a influência dos parâmetros do método de adsorção de camada iônica e reação sucessivas (SILAR) na obtenção de filmes de ZnO nanoestruturados sobre substrato de vidro recoberto com óxido de estanho dopado com flúor (SnO2:F). Na temperatura de 90°C ocorreu a formação de ZnO e o aumento de nanoestruturas formadas. A quantidade de ciclos e responsável pela densidade superficial, o crescimento acelerase após se atingir a densidade superficial critica. O tempo de permanência no banho de nucleação não tem influência significativa, já no banho de crescimento com o aumento do tempo ocorreu coalescimento das nanoestruturas. O uso do cloreto de zinco como precursor no banho de nucleação apresentou crescimento mais lento para concentrações molares baixas, o aumento da concentração molar resultou em filmes porosos. Os resultados obtidos neste estudo mostraram que alterações simples nas variáveis do processo SILAR para obtenção de ZnO permitiram desde a obtenção de nanoestruturas individuais a filmes compactos ou porosos.

    Palavras-Chave: zinc oxides; adsorption; layers; nanostructures; thin films

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  • IPEN-DOC 28536

    THIPE, VELAPHI C. ; LIMA, CAROLINE S.A. ; NOGUEIRA, KAMILA M. ; BATISTA, JORGE G.S. ; FERREIRA, ARYEL H. ; KATTI, KATTESH V.; LUGAO, ADEMAR B. . Silver nanoparticles applications and ecotoxicology for controlling mycotoxins. In: ABD-ELSALAM, KAMEL A. (Ed.). Silver Nanomaterials for Agri-Food Applications. Amsterdam, Netherlands: Elsevier, 2021. p. 549-575, cap. 23. DOI: 10.1016/B978-0-12-823528-7.00019-6

    Palavras-Chave: nanoparticles; silver; mycotoxins; fungi; nutritional deficiency; agriculture

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  • IPEN-DOC 28535

    LANDULFO, EDUARDO ; CACHEFFO, ALEXANDRE ; YOSHIDA, ALEXANDRE C. ; GOMES, ANTONIO A. ; LOPES, FABIO J. da S. ; MOREIRA, GREGORI de A. ; SILVA, JONATAN J. da ; ANDRIOLI, VANIA; PIMENTA, ALEXANDRE; WANG, CHI; XU, JIYAO; MARTINS, MARIA P.P.; BATISTA, PAULO; BARBOSA, HENRIQUE de M.J.; GOUVEIA, DIEGO A.; GONZALEZ, BORIS B.; ZAMORANO, FELIX; QUEL, EDUARDO; PEREIRA, CLODOMYRA; WOLFRAM, ELIAN; CASASOLA, FACUNDO I.; ORTE, FACUNDO; SALVADOR, JACOBO O.; PALLOTTA, JUAN V.; OTERO, LIDIA A.; PRIETO, MARIA; RISTORI, PABLO R.; BRUSCA, SILVINA; ESTUPINAN, JOHN H.R.; BARRERA, ESTIVEN S.; ANTUNA-MARRERO, JUAN C.; FORNO, RICARDO; ANDRADE, MARCOS; HOELZEMANN, JUDITH J.; GUEDES, ANDERSON G.; SOUSA, CRISTINA T.; OLIVEIRA, DANIEL C.F. dos S.; DUARTE, EDICLE de S.F.; SILVA, MARCOS P.A. da; SANTOS, RENATA S. da S. . Lidar observations in South America: Part II - troposphere. In: HAMMOND, ANDREW (Ed.). Remote Sensing. London, United Kingdom: IntechOpen, 2021. p. 1-36, cap. 2. DOI: 10.5772/intechopen.95451

    Abstract: In Part II of this chapter, we intend to show the significant advances and results concerning aerosols’ tropospheric monitoring in South America. The tropospheric lidar monitoring is also supported by the Latin American Lidar Network (LALINET). It is concerned about aerosols originating from urban pollution, biomass burning, desert dust, sea spray, and other primary sources. Cloud studies and their impact on radiative transfer using tropospheric lidar measurements are also presented.

    Palavras-Chave: environment; environmental quality; air quality; air pollution monitoring; controlled atmospheres; aerosols; optical radar; atmospheres; satellite atmospheres

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  • IPEN-DOC 28534

    LANDULFO, EDUARDO ; CACHEFFO, ALEXANDRE ; YOSHIDA, ALEXANDRE C. ; GOMES, ANTONIO A. ; LOPES, FABIO J. da S. ; MOREIRA, GREGORI de A. ; SILVA, JONATAN J. da ; ANDRIOLI, VANIA; PIMENTA, ALEXANDRE; WANG, CHI; XU, JIYAO; MARTINS, MARIA P.P.; BATISTA, PAULO; BARBOSA, HENRIQUE de M.J.; GOUVEIA, DIEGO A.; GONZALEZ, BORIS B.; ZAMORANO, FELIX; QUEL, EDUARDO; PEREIRA, CLODOMYRA; WOLFRAM, ELIAN; CASASOLA, FACUNDO I.; ORTE, FACUNDO; SALVADOR, JACOBO O.; PALLOTTA, JUAN V.; OTERO, LIDIA A.; PRIETO, MARIA; RISTORI, PABLO R.; BRUSCA, SILVINA; ESTUPINAN, JOHN H.R.; BARRERA, ESTIVEN S.; ANTUNA-MARRERO, JUAN C.; FORNO, RICARDO; ANDRADE, MARCOS; HOELZEMANN, JUDITH J.; GUEDES, ANDERSON G.; SOUSA, CRISTINA T.; OLIVEIRA, DANIEL C.F. dos S.; DUARTE, EDICLE de S.F.; SILVA, MARCOS P.A. da; SANTOS, RENATA S. da S. . Lidar observations in South America: Part I - mesosphere and stratosphere. In: HAMMOND, ANDREW (Ed.). Remote Sensing. London, United Kingdom: IntechOpen, 2021. p. 1-23, cap. 1. DOI: 10.5772/intechopen.95038

    Abstract: South America covers a large area of the globe and plays a fundamental function in its climate change, geographical features, and natural resources. However, it still is a developing area, and natural resource management and energy production are far from a sustainable framework, impacting the air quality of the area and needs much improvement in monitoring. There are significant activities regarding laser remote sensing of the atmosphere at different levels for different purposes. Among these activities, we can mention the mesospheric probing of sodium measurements and stratospheric monitoring of ozone, and the study of wind and gravity waves. Some of these activities are long-lasting and count on the support from the Latin American Lidar Network (LALINET). We intend to pinpoint the most significant scientific achievements and show the potential of carrying out remote sensing activities in the continent and show its correlations with other earth science connections and synergies. In Part I of this chapter, we will present an overview and significant results of lidar observations in the mesosphere and stratosphere. Part II will be dedicated to tropospheric observations.

    Palavras-Chave: environment; air quality; atmospheres; remote sensing; earth atmosphere; optical radar; satellite atmospheres

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  • IPEN-DOC 28533

    DONATUS, UYIME ; BODUNRIN, MICHAEL O.; OLAYINKA, AYOTUNDE; MILAGRE, MARIANA X. ; OLOYEDE, OLAMILEKAN R.; ARIBO, SUNDAY; ARAUJO, JOAO V. de S. ; MACHADO, CARULINE de S.C. ; COSTA, ISOLDA . Corrosion resistance of precipitation-hardened Al alloys: a comparison between new generation Al-Cu-Li and conventional alloys. In: DOBRZANSKI, LESZEK A. (Ed.). Advanced Aluminium Composites and Alloys. London, United Kingdom: IntechOpen, 2021. p. 1-28, cap. 5. DOI: 10.5772/intechopen.92807

    Abstract: The corrosion resistance of conventional (AA2024-T3, AA6082-T6 and AA7050-T7451) and the new generation (AA2050-T84, AA2098-T351, AA2198-T8, and AA2198-T851) precipitation-hardened alloys has been studied and compared using electrochemical and non-electrochemical approaches. The AA6082-T6 was the most resistant alloy followed by the new generation Al-Cu-Li alloys, except the AA2050-T84. All the alloys exhibited pseudo-passivity, except for the AA2024-T3 alloy which presented the highest number of pitting sites per cm2 and also exhibited the most insidious form of corrosion amongst the alloys tested. However, the alloy with the highest corrosion depth was the AA2050-T84 alloy followed by the AA2024-T3 and AA7050-T7451 alloys. Intergranular corrosion was associated with rapid rates of penetration. In addition to the microstructural features of the alloys before corrosion, the modes of localized corrosion in the alloys were also influenced by evolving microstructural features (such as re-deposited Cu) during corrosion.

    Palavras-Chave: aluminium alloys; corrosion resistance; microstructure; aluminium compounds; electrochemistry

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  • IPEN-DOC 28532

    SOUZA, STEPHAN P.M. de; TOBAR, NATALIA; FRASSON, FERNANDA; PERINI, EFRAIN A. ; SOUZA, CARMINO A. de; DELAMAIN, MARCIA T.; RAMOS, CELSO D.. Head-to-head comparison between 68Ga-PSMA and 18F-FDG-PET/CT in lymphomas: a preliminary analysis. Nuclear Medicine Communications, v. 42, n. 12, p. 1355-1360, 2021. DOI: 10.1097/MNM.0000000000001465

    Abstract: Purpose: Isolated case reports mention the uptake of radiolabeled PSMA in lymphoma. However, it is not clear if the intensity of 68Ga-PSMA expression varies among different histological subtypes or if it correlates with 18F-FDG uptake. This study compared both tracers in patients with diverse lymphoma subtypes. Methods: Ten patients with biopsy-proven-lymphoma underwent 18F-FDG and 68Ga-PSMA-PET/CT (maximum time interval: 6 days). Lymphoma subtypes included Hodgkin’s lymphoma (HL, three patients) and aggressive and indolent non-Hodgkin’s lymphoma (NHL, seven patients). The intensity of PSMA uptake was classified visually as low, intermediate, or high, using blood pool, liver and parotid gland uptake as references. Maximum standardized-uptake value (SUVmax) of each affected site was measured in both sets of images. Results: FDG detected 59/59 involved sites in 10 patients and PSMA 47/59 sites in nine patients. PSMA uptake was generally low, regardless of the intensity of FDG uptake, but it was classified as intermediate in two patients. The median SUVmax varied from 2.0 (2.0–8.2) to 30.9 for FDG and from 1.7 (1.7–1.7) to 4.4 for PSMA, P < 0.0001. The primary lesion of one patient had a marked intralesional mismatch uptake pattern of the tracers, with areas of higher PSMA expression than FDG uptake, and vice-versa. A brain lesion was more easily identified with PSMA than with FDG images. Conclusion: HL and several NHL subtypes may present PSMA uptake. The intensity of PSMA expression is generally lower than that of FDG uptake and seems to present less variation among the different histological subtypes of lymphomas.

    Palavras-Chave: diagnosis; neoplasms; prostate; antigens; gallium 68; lymphomas; hodgkins disease

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  • IPEN-DOC 28531

    MACHADO, CARULINE de S.C. ; SILVA, REJANE M.P. da ; ARAUJO, JOAO V. de S. ; MILAGRE, MARIANA X. ; DONATUS, UYIME ; VIVEIROS, BARBARA V.G. de ; KLUMPP, RAFAEL E. ; COSTA, ISOLDA . Influence of chloride ions concentration on the development of severe localised corrosion and its effects on the electrochemical response of the 2198-T8 alloy. Corrosion Engineering, Science and Technology, v. 56, n. 4, p. 341-350, 2021. DOI: 10.1080/1478422X.2020.1862390

    Abstract: The development of severe localised corrosion (SLC) on the 2198-T8 alloy was investigated in solutions of various NaCl concentrations (0.001, 0.005 and 0.01 mol L−1). Immersion tests, optical profilometry, conventional and local electrochemical analyses were performed to evaluate the corrosion behaviour of the alloy. Immersion tests showed that the alloy is susceptible to SLC in all conditions, although the pits sizes were dependent on the solution concentration. The largest anodic areas, corresponding to SLC sites, were observed for the sample immersed in 0.001 mol L−1 NaCl, whereas pits with similar sizes were observed for the samples immersed in solutions with 0.005 and 0.01 mol L−1 of NaCl. Moreover, the maximum depth of attack was observed for the sample immersed in 0.001 mol L−1 NaCl. These results were in agreement with the scanning ionselective electrode technique (SIET) maps which showed stronger acidification on the sample exposed to 0.001 mol L−1 NaCl solution.

    Palavras-Chave: aluminium alloys; lithium alloys; copper alloys; chlorides; ions; corrosion

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  • IPEN-DOC 28530

    SILVA, PAULO S.C. da ; CAMPOS, MARCIA P. de ; EL HAJJ, THAMMIRIS M.; REIS, GUILHERME de L. . Radon concentrations in a nuclear reactor center in Brazil. Health Physics, v. 121, n. 2, p. 117-123, 2021. DOI: 10.1097/HP.0000000000001430

    Abstract: Radiation workers are normally exposed to doses resulting from their day-to-day activities. Besides that, background radiation, such as radon, can contribute to the exposure rates. The radionuclide 222Rn is a noble gas belonging to the uranium series, and its indoor concentration in the air depends on the exhalation from surrounding soil and the exhalation from building materials. Radon exhaling from porous building materials containing high uranium concentrations can become a significant exposure factor in areas with limited ventilation. The objective of this study was to evaluate the 222Rn concentrations in the radiochemistry and radiometric laboratories in the nuclear reactor building of the Nuclear Reactor Center (CERPq) located in the Institute of Nuclear and Energy Research (IPEN), São Paulo, Brazil. Measurements were done using a Radon Gas Monitor, model RAD7, equipped with a solid-state alpha detector. A passive method (SSNTD) was also used, consisting of square pieces of C-39 foils (2.5 cm × 2.5 cm) placed within small diffusion chambers. The CR-39 detectors were etched in KOH 30% solution at 80 °C for 5.5 h in a constant-temperature bath. After etching, the detectors were washed, dried, and scanned using a microscope to obtain the track density measurements. The activity concentrations measured with both techniques varied from 52 to 103 Bq m−3 in the studied areas of the CERPq. These values may be compared to the reference level of 100 Bq m−3 established by the World Health Organization to ensure safety environments.

    Palavras-Chave: radon 222; radiation doses; occupational exposure; reactors

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  • IPEN-DOC 28529

    SCURO, N.L. ; ANGELO, G. ; ANGELO, E.; UMBEHAUN, P.E. ; TORRES, W.M. ; SANTOS, P.H.G. ; FREIRE, L.O. ; ANDRADE, D.A. . RANS-based CFD calculation for pressure drop and mass flow rate distribution in an MTR fuel assembly. Nuclear Science and Engineering, v. 195, n. 4, p. 349-366, 2021. DOI: 10.1080/00295639.2020.1825306

    Abstract: This work presents a Reynolds-averaged Navier Stokes–based computational fluid dynamics methodology for the calculation of pressure drop and mass flow rate distribution in a material test reactor flat-plate-type standard fuel assembly (SFA) of the IEA-R1 Brazilian research reactor to predict future improvements in newer SFA designs. The results improve the understanding of the origin of fuel plate oxidation due to high temperatures, and consequently, due to the internal flow dynamics. All numerical analyses were performed with the ANSYS-CFX® commercial code. The observed results show that the movement pin decreases the central channel mass flow due to the length of the vortex at the inlet region. However, the outlet nozzle showed greater general influence in the flow dynamics. It should have a more gradual cross-section transition being away from the fuel plates or a squarer-shaped design to get a more homogeneous mass flow distribution. Optimizing both regions could lead to a better cooling condition. The validation of the IEA-R1 numerical methodology was made by comparing the McMaster University’s dummy model experiment with a numerical model that uses the same numerical methodology. The experimental data were obtained with laser Doppler velocimetry, and the comparison showed good agreement for both pressure drop and mass flow rate distribution using the Standard k-ω turbulence model.

    Palavras-Chave: computer calculations; computerized simulation; fluid mechanics; materials testing; reactor materials

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  • IPEN-DOC 28528

    FUJIMOTO, T.G. ; STEIL, M.C.; MUCCILLO, E.N.S. . Electrical conductivity of La0.9Sr0.1Ga0.8Mg0.2O3-y-La1.55Sr0.45Ga3O7+δ composite electrolyte. ECS Transactions, v. 103, n. 1, p. 2163-2172, 2021. DOI: 10.1149/10301.2163ecst

    Abstract: Doped lanthanum gallate constitutes a family of solid electrolytes with high ionic conductivity, wide electrolytic domain, and good chemical stability. The combination of its properties turns some compounds of this family promising candidates for application in solid oxide cells operating at intermediate temperatures. In this work, La0.9Sr0.1Ga0.8Mg0.2O3-y - xLa1.55Sr0.45Ga3O7+δ with x = 0, 1, and 5 wt.% were investigated aiming to obtain a composite solid electrolyte with optimized properties compared to the parent material. Composite electrolytes were prepared by solid state reaction method and evaluated for densification, phase content, and microstructure. Electrical conductivity measurements were carried out as a function of temperature and oxygen partial pressure. Increase on densification and structural homogeneity were obtained with increasing fraction of the melilite phase. The electrical conductivity determined by impedance spectroscopy revealed a decrease of the bulk resistivity for increasing amounts of La1.55Sr0.45Ga3O7+δ.

    Palavras-Chave: composite materials; electric conductivity; doped materials; electrolytes

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  • IPEN-DOC 28527

    FONSECA, F.C. ; TABUTI, F. ; MORAES, T. ; ABE, R.; GUIMARAES, R.M.; MIURA, Y.; FUKUYAMA, Y.. Exploring the stability of direct ethanol solid oxide fuel cells at intermediate temperature. ECS Transactions, v. 103, n. 1, p. 169-178, 2021. DOI: 10.1149/10301.0169ecst

    Abstract: Anode supported fuel cells were tested in direct (no water added) bioethanol at intermediate temperature (600°C and 700°C). The standard fuel cell has reasonable short-term stability under dry ethanol if current is continuously drawn at a minimum fuel utilization factor at 700ºC. However, the YSZ/Ni anode develops carbon deposits as inferred from post fuel cell test analyses and fixed bed steam reforming catalytic tests at 600°C. Thus, an active catalytic layer with tailored properties for ethanol internal reforming was studied. Initial tests investigated the Ir/gadolinium-doped ceria catalysts previously proven stable at 850°C. The main results have shown that the catalytic layer has no significant effect on the performance of the fuel cell running under hydrogen. The use of a ceria-based catalytic layer has enhanced the stability of the fuel cell under dry ethanol at 700°C, but stable operation at 600°C requires the development of more active catalyst.

    Palavras-Chave: ethanol; solid oxide fuel cells; direct ethanol fuel cells; raman spectra

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  • IPEN-DOC 28526

    VILELA, V.B. ; THYSSEN, V.V. ; RODRIGUES, L.N. ; FONSECA, F.C. . Enhancing the catalytic activity of lanthanum-ceria fluorite for methane conversion in SOFC. ECS Transactions, v. 103, n. 1, p. 1917-1925, 2021. DOI: 10.1149/10301.1917ecst

    Abstract: A2B2O7 compounds with tailored compositions exhibit catalytic properties in a variety of high-temperature reactions, such as oxidative coupling of methane (OCM). La2Ce2O7 performs well in OCM due to selective mobile oxygen species, and suitable alkaline sites. Doping with Ca2+ increases the alkalinity, which can considerably increase selectivity for C2 products in OCM. We have explored the combustion synthesis to obtain homogeneous Ca2+-doped La2Ce2O7 materials to use as a catalytic layer in SOFC reactors for methane direct conversion to C2. The addition of Ca2+ in the A site of La2Ce2O7 resulted in the disordered fluorite-type crystalline structure. The formation of superficial oxygen vacancies related to the active oxygen species, which may benefit the OCM reaction, was detected. Electrochemical characterization showed no significant dependence of the conductivity with Ca2+-doping.

    Palavras-Chave: lanthanum oxides; cerium oxides; oxygen compounds; solid oxide fuel cells; catalysts

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  • IPEN-DOC 28525

    RODRIGUES, L.N. ; MACHADO, MARINA ; MORAES, L.P.R. ; THYSSEN, V.V. ; FONSECA, F.C. . Development of anode-supported solid oxide fuel cell by co-tape casting and co-sintering. ECS Transactions, v. 103, n. 1, p. 2245-2251, 2021. DOI: 10.1149/10301.2245ecst

    Abstract: Simple and cost-effective technologies to produce solid oxide fuel cells require control of microstructure, thickness, homogeneity, and reproducibility of the functional layers. The manufacturing of a solid oxide fuel cell (SOFC) involves significant ceramic processing challenges to obtain layers with controlled microstructure. Possibly the most common technique for large-scale production of SOFCs is tape casting. In this study, YSZ electrolyte and 60NiO/YSZ anode slurries were studied for the production of half-cells deposited by the sequential tape casting technique. A co-sintering procedure was developed for the half-cells and after cathode deposition the single cells were tested.

    Palavras-Chave: solid oxide fuel cells; anodes; casting; viscosity

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  • IPEN-DOC 28524

    BOSCH-SANTOS, B. ; CABRERA-PASCA, G.A.; CORREA, E.L. ; CORREA, B.S. ; SALES, T.N.S. ; MOON, K-W.; DENNIS, C.L.; HUANG, Q.; LEAO, J.B.; LYNN, J.W.; CARBONARI, A.W. . Magnetic and structural properties of the intermetallic Ce(1−x)LaxCrGe3 series of compounds. Physical Review Materials, v. 5, n. 11, p. 114406-1 - 114406-11, 2021. DOI: 10.1103/PhysRevMaterials.5.114406

    Abstract: The Ce(1−x)LaxCrGe3 (x = 0, 0.19, 0.43, 0.58, and 1) intermetallic compound system has been investigated by magnetization measurements and neutron scattering techniques to determine the effect of La doping on the magnetic ordering and exchange interaction between Cr ions. The structural and magnetic characterization in this series was first verified by x-ray diffraction and bulk magnetization measurements. The samples exhibit the known hexagonal perovskite structure (P63/mmc space group) and have a single magnetic phase according to magnetizationmeasurements. In this paper, the ferromagnetic ordering temperature for Cr evolves smoothly from a range of 68 K to 77 K for CeCrGe3 to a range of 91 K to 96 K for LaCrGe3 as La replaces Ce. Magnetization results indicate the formation of domain walls below the transition temperature for all Ce(1−x)LaxCrGe3 systems investigated. Neutron results indicate ordered magnetic Cr moments aligned along the c axis for the x = 1 LaCrGe3 system, as well as for x = 0.19, 0.43, and 0.58, which contrasts with the x = 0 CeCrGe3 where the moments order in the ab plane.

    Palavras-Chave: magnetic properties; intermetallic compounds; magnetization; neutron dosimetry

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  • IPEN-DOC 28523

    SANTOS, SILAS ; RODRIGUES, ORLANDO ; CAMPOS, LETICIA . A glance on rare earth oxides: importance, reserves, demand, applications, critical uncertainties, global economy, and zeta potential characterization. Current Smart Materials, v. 5, n. 2, p. 79-100, 2021. DOI: 10.2174/2405465805999200628095450

    Abstract: Background: Innovation mission in material science requires new approaches to form functional materials, wherein the concept of its formation begins in nano/micro scale. Rare earth oxides with general form (RE2O3; RE from La to Lu, including Sc and Y) exhibit particular proprieties, being used in a vast field of applications with high technological content since agriculture to astronomy. Despite their applicability, there is a lack of studies on the surface chemistry of rare earth oxides. Zeta potential determination provides key parameters to form smart materials by controlling interparticle forces, as well as their evolution during processing. This paper reports a study on zeta potential with emphasis on rare earth oxide nanoparticles. A brief overview of rare earths, as well as zeta potential, including sample preparation, measurement parameters, and the most common mistakes during this evaluation are reported. Methods: A brief overview of rare earths, including zeta potential, and interparticle forces are presented. A practical study on zeta potential of rare earth oxides - RE2O3 (RE as Y, Dy, Tm, Eu, and Ce) in aqueous media is reported. Moreover, sample preparation, measurement parameters, and common mistakes during this evaluation are discussed. Results: Potential zeta values depend on particle characteristics such as size, shape, density, and surface area. Besides, the preparation of samples, which involves electrolyte concentration and time for homogenization of suspensions, is extremely valuable to get suitable results. Conclusion: Zeta potential evaluation provides key parameters to produce smart materials through which interparticle forces can be controlled. Even though zeta potential characterization is mature, investigations on rare earth oxides are very scarce. Therefore, this innovative paper is a valuable contribution to this field.

    Palavras-Chave: rare earths; nanoparticles; electrolytes; colloids; ceramics; electrophoresis

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  • IPEN-DOC 28522

    SANTOS, SILAS C. ; RODRIGUES JUNIOR, ORLANDO ; CAMPOS, LETICIA . Microstructure evolution of yttria compacts by powder technology. Current Smart Materials, v. 5, n. 2, p. 122-128, 2021. DOI: 10.2174/2405465805666210120102315

    Abstract: Background: Innovation in ceramic materials relies on the processing of powders. Yttria, also known as yttrium oxide, belongs to the rare-earth group (RE2O3 - RE from La to Lu, including Sc and Y). Due to the great properties and end-use of RE-based materials since agriculture until astronomy, studies on processing, sintering and microstructural evolution of RE-based materials are essential to provide new materials with improved characteristics. The aim of this paper is to obtain dense compacts of yttria by powder technology, in which the effect of sintering temperature on sample's microstructure is evaluated. Methods: Yttria powders (Y2O3) were characterized by Photon Correlation Spectroscopy (PCS), X-ray Diffraction (XRD), and Scanning Electron Microscopy (SEM). Cylindrical powder compacts were produced by uniaxial compaction, followed by hydrostatic compaction. Sintered samples obtained under sintering temperatures from 1350 to 1550ºC were evaluated by SEM, XRD, apparent density, and true density. Results: Cubic C-type yttria powders exhibited a mean particle size (d50) of 1.6μm, and morphology like acicular. Powder compacts (diameter x height) of 9.57mm ± 0.01 x 1.53mm ± 0.01 presented mean apparent density of 53.69% (based on free powder density). Sintered samples at 1550ºC exhibited the most densification, 65.0% related to the green density and 91.0% related to theoretical density, respectively. Conclusion: Yttria cylindrical compacts with dense microstructure, and symmetric dimensions were formed by powder technology from powders with a mean particle size of 6.51μm, by compaction methods (uniaxial and hydrostatic), followed by sintering. The most densification of samples was achieved by the sintering condition of 1550ºC for 2h, providing samples with a theoretical density of 91%. These results provide useful subsidies to advance toward full densification of yttria-based materials.

    Palavras-Chave: microstructure; yttrium; rare earths; sintering; powders; photons; correlations

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  • IPEN-DOC 28521

    CALABRESE, S.; CAVALLARO, M.; CARBONE, D.; CAPPUZZELLO, F.; AGODI, C.; BURRELLO, S.; DE GREGORIO, G.; FERREIRA, J.L.; GARGANO, A.; SGOUROS, O.; ACOSTA, L.; AMADOR-VALENZUELA, P.; BELLONE, J.I.; BORELLO-LEWIN, T.; BRISCHETTO, G.A.; CALVO, D.; CAPIROSSI, V.; CHAVEZ LOMELI, E.R.; CIRALDO, I.; COLONNA, M.; DELAUNAY, F.; DJAPO, H.; EKE, C.; FINOCCHIARO, P.; FIRAT, S.; FISICHELLA, M.; FOTI, A.; GUAZZELLI, M.A.; HACISALIHOGLU, A.; IAZZI, F.; LA FAUCI, L.; LAY, J.A.; LINARES, R.; LUBIAN, J.; MEDINA, N.H.; MORALLES, M. ; OLIVEIRA, J.R.B.; PAKOU, A.; PANDOLA, L.; PETRASCU, H.; PINNA, F.; RUSSO, G.; SOLAKCI, S.O.; SOUKERAS, V.; SOULIOTIS, G.; SPATAFORA, A.; TORRESI, D.; TUDISCO, S.; YILDIRIN, A.; ZAGATTO, V.A.B.. 18O-induced single-nucleon transfer reactions on 40Ca at 15.3A MeV within a multichannel analysis. Physical Review C, v. 104, n. 6, p. 064609-1 - 064609-12, 2021. DOI: 10.1103/PhysRevC.104.064609

    Abstract: Background: Nucleon transfer reactions are selective tools for nuclear physics investigations. The theoretical and computational limits affecting in the past their data analysis could be nowadays surmounted thanks to the advent of methods with refined approximations and constraints, even when heavy-ion collisions are considered. Purpose: Modern microscopic calculations of heavy-ion-induced transfer reactions combined with precise experimental data offer the chance for accurately testing different reaction models as well as the nuclear structure description of the involved nuclear states. Method: Single proton and neutron transfer reactions were measured with theMAGNEX magnetic spectrometer for the 18O+40Ca system at 15.3A MeV. Excitation energy spectra and angular differential cross section distributions were extracted. The experimental results are compared with theoretical calculations performed in distorted wave and coupled channel Born approximation. The use of a coupled channel equivalent polarization potential to effectively describe the coupling effects affecting the initial state interaction is also considered. Spectroscopic amplitudes derived from a large-scale shell model with appropriate interactions adapted for the involved nuclei are employed. Results: Our theoretical calculations are in good agreement with experimental data, without the need for any scaling factor, validating the adopted reaction and nuclear structure parameters. Moreover, under the present experimental conditions, a weak dependence of the obtained results on the choice of the reaction models was observed. Conclusions: The good agreement between experimental and theoretical results validates the reliability of the parameter sets entering the calculations. They are extracted from or tested in complementary analyses of other reaction channels under the same experimental conditions. Such a multichannel approach represents the best option to pursue a solid, comprehensive, and model-independent description of the single-nucleon transfer reactions. The successful description of the present one-nucleon transfer data is also propaedeutic to the accurate assessment, under the same theoretical description, of higher-order transfer processes, like the sequential nucleon transfer mechanisms which are in competition with the direct charge exchange reactions.

    Palavras-Chave: nucleon reactions; calcium 40; oxygen 18; calculation methods; born approximation; distorted wave theory; magnets

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  • IPEN-DOC 28520

    LA FAUCI, L.; SPATAFORA, A.; CAPPUZZELLO, F.; AGODI, C.; CARBONE, D.; CAVALLARO, M.; LUBIAN, J.; ACOSTA, L.; AMADOR-VALENZUELA, P.; BORELLO-LEWIN, T.; BRISCHETTO, G.A.; CALABRESE, S.; CALVO, D.; CAPIROSSI, V.; CHAVEZ LOMELI, E.R.; CIRALDO, I.; CUTULI, M.; DELAUNAY, F.; DJAPO, H.; EKE, C.; FINOCCHIARO, P.; FIRAT, S.; FISICHELLA, M.; FOTI, A.; GUAZZELLI, M.A.; HACISALIHOGLU, A.; IAZZI, F.; LINARES, R.; MA, J.; MEDINA, N.H.; MORALLES, M. ; OLIVEIRA, J.R.B.; PAKOU, A.; PANDOLA, L.; PETRASCU, H.; PINNA, F.; RIES, P.C.; RUSSO, G.; SGOUROS, O.; SOLAKCI, S.O.; SOUKERAS, V.; SOULIOTIS, G.; TORRESI, D.; TUDISCO, S.; WANG, J.; YANG, Y.; YILDIRIN, A.; ZAGATTO, V.A.B.. 18O+76Se elastic and inelastic scattering at 275 MeV. Physical Review C, v. 104, n. 5, p. 054610-1 - 054610-9, 2021. DOI: 10.1103/PhysRevC.104.054610

    Abstract: Background: An accurate description of the initial and final state interactions in the 18O+76Se collision is demanded by the NUMEN project. The study of single and double charge exchange nuclear reactions is the main purpose for NUMEN, since these can be used as tools to provide experimentally driven information about nuclear matrix elements of interest in the context of neutrinoless double-β decay. To date, the details of the optical potentials and nuclear response to isospin operators for many of the projectile-target systems proposed for the NUMEN double charge exchange studies are poorly known. The 18O+76Se case, here under study, is particularly relevant due to its connection with the 76Ge neutrinoless double-β decay. Purpose: In this work the authors want to characterize the initial-state interaction for the 18O+76Se reactions at 275 MeV incident energy determining the optical potential and evaluating the effect of couplings with the inelastic scattering on the elastic channel. Methods: The angular distributions of differential cross section were measured in the angular region between 4◦ and 22◦ in the center-of-mass reference frame. The cross sections were compared with theoretical calculations, that adopt different optical potentials. Coupling effects on the elastic channel were determined into the coupled channels formalism. Results: The excitation energy spectrum of the colliding nuclei and the cross section angular distributions were measured with satisfactory energy resolution. The elastic scattering cross section is not well reproduced in the full angular range explored when the optical model approach is adopted. A good agreement is found using coupled channel calculations. The initial state interaction for the 18O+76Se nuclear reactions at 275 MeV is determined. Conclusions: Coupled channels effects are crucial to obtain a good description of the measured elastic and inelastic channels cross sections, even at large transferred momenta where the optical model approach fails in reproducing the experimental data. The role of channel coupling could be relevant also in the analysis of other open reaction channels in the same collision and should be accounted for in double charge exchange analyses as well.

    Palavras-Chave: oxygen 18; selenium 76; elastic scattering; inelastic scattering; nuclear reactions

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  • IPEN-DOC 28519

    CAPPUZZELLO, FRANCESCO; AGODI, CLEMENTINA; CALABRETTA, LUCIANO; CALVO, DANIELA; CARBONE, DIANA; CAVALLARO, MANUELA; COLONNA, MARIA; FINOCCHIARO, PAOLO; IAZZI, FELICE; LINARES, ROBERTO; OLIVEIRA, JOSE R.B.; PANDOLA, LUCIANO; SANTOPINTO, ELENA; TORRESI, DOMENICO; TUDISCO, SALVATORE; ACOSTA, LUIS; ALTANA, CARMEN; AMADOR-VALENZUELA, PAULINA; AVANZI, LUIS H.; BELLONE, JESSICA; BONANNO, DANILO; BOZTOSUN, ISMAIL; BRASOLIN, SANDRO; BRISCHETTO, GIUSEPPE A.; BRUNASSO, OSCAR; CALABRESE, SALVATORE; CAMPAJOLA, LUIGI; CAPIROSSI, VITTORIA; LOMELI, EFRAIN R.C.; CIRALDO, IRENE; AGUIAR, VITOR A.P. DE; DELAUNAY, FRANCK; FERRARESI, CARLO; FISICHELLA, MARIA; GANDOLFO, ELISA; GUAZZELLI, MARCILEI A.; LA VIA, FRANCESCO; LAMBARRI, DANIEL J.M.; LENSKE, HORST; LUBIAN, JESUS; MEDINA, NILBERTO H.; MEREU, PAOLO; MORALLES, MAURICIO ; MUOIO, ANNAMARIA; PETRASCU, HORIA; PINNA, FEDERICO; SARTIRANA, DIEGO; SGOUROS, ONOUFRIOS; SOLAKCI, SELCUK O.; SOUKERAS, VASILIS; SPATAFORA, ALESSANDRO; RUSSO, ANTONIO D.; YILDIRIM, AYDIN. The NUMEN Technical Design Report. International Journal of Modern Physics A, v. 36, n. 30, p. 2130018-1 - 2130018-155, 2021. DOI: 10.1142/S0217751X21300180

    Abstract: NUMEN proposes an innovative technique to access the nuclear matrix elements entering the expression of the lifetime of the double beta decay by cross-section measurements of heavy-ion induced Double Charge Exchange (DCE) reactions. Despite the fact that the two processes, namely neutrinoless double beta decay and DCE reactions, are triggered by the weak and strong interaction respectively, important analogies are suggested. The basic point is the coincidence of the initial and final state many-body wave functions in the two types of processes and the formal similarity of the transition operators. The main experimental tools for this project are the K800 Superconducting Cyclotron and MAGNEX spectrometer at the INFN-LNS laboratory. However, the tiny values of DCE cross-sections and the resolution requirements demand beam intensities much higher than those manageable with the present facility. The on-going upgrade of the INFN-LNS facilities promoted by the POTLNSa project in this perspective is intimately connected to the NUMEN project. This paper describes the solutions proposed as a result of the R&D activity performed during the recent years. The goal is to develop suitable technologies allowing for the measurements of DCE cross-section under extremely high beam intensities.

    Palavras-Chave: nuclear matrix; neutrinoless double beta decay; neutrinos; matrix elements; heavy ions; nuclear reactions; beam luminosity

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  • IPEN-DOC 28518

    BUSTILLOS, OSCAR V. . O defeito de massa na espectrometria de massas. Revista Analytica, v. 19, n. 113, p. 18-21, 2021.

    Palavras-Chave: mass defect; mass spectroscopy; nuclear physics; mass number

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  • IPEN-DOC 28517

    RODRIGUES, RENATA B. ; SILVA, MARIA E. da C. ; MARTINS, JOAO P. de F.. A importância do Bacillus subtilis natto na producão de uma enzima especial com propriedades medicinais: a nattoquinase. Revista Analytica, v. 19, n. 113, p. 7-13, 2021.

    Abstract: A nattoquinase é uma enzima que tem ações fibrinolítica e trombolítica que traz uma ampla aplicabilidade para o tratamento de patologias clínicas humanas. Trata-se de uma protease alcalina extraída do microorganismo não patogênico Bacillus subtilis natto. Recentes pesquisas demonstraram que o gênero Bacillus, em especial, a espécie e sua variação B. subtillis var. natto, possui propriedades prebiótica e probiótica, devido sua atividade fermentativa de grãos, tais como, soja, feijão, grão de bico, entre outros, permitindo naturalmente gerar resistência aos fitopatógenos comuns na agricultura. Dessa maneira, os alimentos que fermentam tornam-se fontes importantes que ativam o sistema imunológico no homem, previne o desenvolvimento de determinadas doenças e oferece condições ao organismo de reagir àquelas doenças que estão se manifestando. Dessa maneira, o consumo de alimentos fermentandos através do B. subtillis natto, poderá fazer parte das necessidades nutricionais, isto é, ricos em nutrientes. Essa espécie em especial, possibilita que aminoácidos e vitaminas de grãos estejam mais disponíveis, ou seja, alientos de “alta densidade nutricional” e que estão diretamente associados ao binômio saúde-doença, prevalecendo a saúde e o bem-estar das pessoas que as consomem (conhecidos como alimentos biofermentados); indicados para todas as idades, porém, ainda é pouco divulgado e, nota-se seu consumo, principalmente, adquiridos através dos hábitos alimentares, como por exemplo, pelos japoneses. A longivitude de muitos povos pode estar atrelada ao escolher alimentos saúdaveis que permitem o envelhecimento com saúde. Assim, envelhecer é uma escolha e exige esforços em todas as esferas e diretrizes: sociais, culturais, econômicas e políticas. A soja Natto, nome escolhido devido à prática do cultivo pelos povos orientais, é obtida apenas da fermentação do Bacillus subtilis natto. Ao fermentar o grão, o bacilo, como resposta da quebra de aminoácidos, produz a chamada enzima nattoquinase ou nattokinase, que possui propriedades fibrinolíticas, isto significa que possuem mecanismos fibrinolíticos. Em suma, a nattoquinase quebra as fibrinas e evita a formação de trombos (coágulos) nos vasos sanguíneos (é um trombolítico natural). Diante a leitura de artigos científicos direcionados ao assunto, o objetivo desse trabalho é relatar sobre a propriedade meritória do B. subtillis natto de produzir a enzima nattoquinase, um atenuante natural indispensável para o controle e cura de determinadas enfermidades sanguíneas.

    Palavras-Chave: enzymes; fibrinolytic agents; bacillus subtilis; thrombosis

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  • IPEN-DOC 28516

    SILVA, MARCOS J. da; ALVES, WELLINGTON ; GRAEFF, CARLOS F. de O.; D'ALPINO, PAULO H.P.. Modified synthesis and physicochemical characterization of a bioglass-based composite for guided bone regeneration. The Scientific World Journal, v. 2021, p. 1-9, 2021. DOI: 10.1155/2021/4295433

    Abstract: Objectives. Bioglass composites and polymers are materials of great interest for the medical and dental areas due to their properties, combining the bioactivity of ceramic materials and the mechanical properties of polymers. The purpose of the present study was to develop and to characterize the physicochemical and morphological properties an experimental bioglass-based ternary composite composed associated with sodium carboxymethylcellulose (Na-CMC) and polyvinyl alcohol (PVA). The compatibility of functional groups with bioglass was previously evaluated. The composite was then synthesized and evaluated in terms of morphology, elemental composition, compressive strength, porosity, and bioactivity. Materials and Methods. The bioglass was previously synthesized using a sol-gel route and characterized using FTIR analysis to identify the functional groups. The bone graft composite was then synthesized associating the bioglass with PVA, surfactant Triton X, and Na-CMC. The composite was then morphologically characterized using SEM/EDS. The porosity of the composite was analyzed using µCT, which also provided the composite compression strength. The composite was then evaluated in terms of its bioactivity using SEM/EDS analyses after immersion in SBF for 12, 24, 48, and 72 h. Results. FTIR analysis confirmed, among other components, the presence of Si–O–Ca and Si–O–Si bonds, compatible with bioglass. SEM analysis exhibited a composite with a porous structure without spikes. The elemental mapping confirmed the presence of Si, Ca, and P in the composite. µCT analysis demonstrated a porous structure with 42.67% of open pores and an average compression strength of 124.7 MPa. It has also demonstrated ionic changes in the composite surface after immersion in SBF, with increasing detection of Ca and P as a function of time, highlighting its chemical bioactivity. Conclusions. It can be concluded that the proposed bioglass-based composite presents a three-dimensional, well-structured, chemically bioactive porous structure, mechanically resistant for being reinforced with polymeric phases, with promising results as a synthetic bone graft, which makes it suitable for guided bone regeneration.

    Palavras-Chave: composite materials; glass; skeleton; biological regeneration; grafts

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  • IPEN-DOC 28515

    COTRIM, LUCAS P.; JOSE, MARCOS M.; CABRAL, EDUARDO L.L. . Reinforcement learning control of robot manipulator. Revista Brasileira de Computação Aplicada, v. 13, n. 3, p. 42-53, 2021. DOI: 10.5335/rbca.v13i3.12091

    Abstract: Since the establishment of robotics in industrial applications, industrial robot programming involves the repetitive and time-consuming process of manually specifying a fixed trajectory, resulting in machine idle time in production and the necessity of completely reprogramming the robot for different tasks. The increasing number of robotics applications in unstructured environments requires not only intelligent but also reactive controllers due to the unpredictability of the environment and safety measures, respectively. This paper presents a comparative analysis of two classes of Reinforcement Learning algorithms, value iteration (Q-Learning/DQN) and policy iteration (REINFORCE), applied to the discretized task of positioning a robotic manipulator in an obstacle-filled simulated environment, with no previous knowledge of the obstacles’ positions or of the robot arm dynamics. The agent’s performance and algorithm convergence are analyzed under different reward functions and on four increasingly complex test projects: 1-Degree of Freedom (DOF) robot, 2-DOF robot, Kuka KR16 Industrial robot, Kuka KR16 Industrial robot with random setpoint/obstacle placement. The DQN algorithm presented significantly better performance and reduced training time across all test projects, and the third reward function generated better agents for both algorithms.

    Palavras-Chave: control equipment; robots; manipulators; learning; artificial intelligence; neural networks

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  • IPEN-DOC 28514

    NOVELLO, GUSTAVO A.M.; YAMAMOTO, HENRIQUE Y.; CABRAL, EDUARDO L.L. . An end-to-end approach to autonomous vehicle control using deep learning. Revista Brasileira de Computação Aplicada, v. 13, n. 3, p. 32-41, 2021. DOI: 10.5335/rbca.v13i3.12135

    Abstract: The objective of this work is to develop an autonomous vehicle controller inside Grand Theft Auto V game, used as a simulation environment. It is used an end-to-end approach, in which the model maps directly the inputs from the image of a car hood camera and a sequence of speed values to three driving commands: steering wheel angle, accelerator pedal pressure and brake pedal pressure. The developedmodel is composed of a convolutional neural network and a recurring neural network. The convolutional network processes the images and the recurrent network processes the speed data. Themodel learns fromdata generated by a human driver´s commands. Two interfaces are developed: one for collecting in-game training data and another to verify the performance of themodel for the autonomous vehicle control. The results show that themodel after training is capable to drive the vehicle as well as a human driver. This proves that a combination of a convolutional network with a recurrent network, using an end-to-end approach, is capable of obtaining a good driving performance even using only images and speed velocity as sensory data.

    Palavras-Chave: vehicles; automation; artificial intelligence; neural networks; learning

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  • IPEN-DOC 28513

    SILVA, PAULA M. da ; SERNA, MARILENE M. ; GALEGO, EGUIBERTO ; FARIA JUNIOR, RUBENS N. . The influence of the nanostructures on the dye adsorption in dye sensitized solar cell. Research & Development in Material science, v. 15, n. 2, p. 1680-1684, 2021. DOI: 10.31031/RDMS.2021.15.000859

    Abstract: In this work, ZnO nanostructures were synthesized by two distinct routes, which consisted in grow distinct morphologies on a seed layer by Chemical Bath Deposition method (CBD) using zinc acetate dihydrate, zinc chloride, zinc sulfate heptahydrate and zinc nitrate hexahydrate as precursor solutions and Ethylenediaminetetraacetic Acid (EDTA) and ammonium chloride as complex agents. The dye Eosin Y salt was adsorbed on the ZnO nanostructures using electrophoresis. The nanostructures were characterized by Scanning Electron Microscopy (SEM), X-ray Fluorescence (XRF) and X-ray Diffraction (XRD). The amount of dye adsorbed on the film surface was evaluated by UV-vis spectrophotometry. The nanostructure prepared from the ZnAc solution presented the higher concentration of dye.

    Palavras-Chave: solar cells; zinc oxides; nanostructures; eosin; electrophoresis

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  • IPEN-DOC 28512

    BENALCAZAR JALKH, E.B.; COELHO, P.G.; WITEK, L.; BERGAMO, E.T.P.; LOPES, A.C.O.; MONTEIRO, K.N.; CESAR, P.F.; GENOVA, L.A. ; LISBOA-FILHO, P.N.; ABREU, J.L.B.; CAMPOS, T.M.B.; CANTEENWALA, A.; BONFANTE, E.A.. Nanoscale physico-mechanical properties of an aging resistant ZTA composite. Journal of the Mechanical Behavior of Biomedical Materials, v. 123, p. 1-8, 2021. DOI: 10.1016/j.jmbbm.2021.104690

    Abstract: Objective: To characterize the effects of aging on the nanomechanical properties and 3D surface topographical parameters of an experimental Zirconia Toughened Alumina (ZTA) composite compared to its respective individual counterpart materials. Methods: Disk-shaped specimens comprised of three material groups were processed: 1) ZTA 70/30 (70% alumina reinforced with 30% second-generation 3Y-TZP); 2) Zpex (Second-generation 3Y-TZP), and; 3) Al2O3 (High purity Alumina) (n = 10/material, 12 × 1 mm). After synthesis, ceramic powders were pressed, the green-body samples were sintered and polished. Nanoindentation testing was performed to record elastic modulus (E) and hardness (H). Interferometry was utilized to assess 3D surface roughness parameters (Sa, Sq), while X-ray diffraction (XRD) and scanning electron microscope (SEM) assessed the crystalline content and microstructure. All tests were performed before and after simulated aging (134°C, 2.2 bar, 20 h). Statistical analyses were performed using linear mixed-model and least square difference pos-hoc tests (α = 5%). Results: XRD spectra indicated increase of monoclinic peaks for Zpex (~18%) relative to ZTA 70/30 (~2.5%) after aging. Additionally, aging did not affect the surface roughness parameters of ZTA 70/30 and Al2O3, although a significant increase in Sa was recorded for Zpex following aging (~90 nm) (p < 0.001). Al2O3 yielded the highest H and E values (H:21 GPa, E: 254 GPa), followed by ZTA 70/30 (H: 13 GPa, E: 214 GPa) and Zpex (H:11 GPa, E: 167 GPa), all significantly different (p < 0.03). Conclusion: ZTA 70/30 and Al2O3 presented high hydrothermal stability with respect to all evaluated variables, where artificial aging significantly increased the monoclinic content and surface roughness of Zpex.

    Palavras-Chave: zirconium oxides; aluminium oxides; mechanical properties; topography; microstructure; indentation testing; nanostructures

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  • IPEN-DOC 28511

    DEL SORDO FILHO, GIOVANNI ; TORRECILHA, JEFFERSON K. ; SCAPIN, MARCOS A. ; OLIVEIRA, SONIA M.B.; SILVA, PAULO S.C. da . Characterization and adsorption capacity of Brazilian kaolin. Journal of Radioanalytical and Nuclear Chemistry, v. 329, n. 1, p. 61-70, 2021. DOI: 10.1007/s10967-021-07674-3

    Abstract: This study has evaluated chemical, radiological composition and determined the cation exchange capacity (CEC) for three commercially available Brazilians raw kaolins. The mineralogical characterization indicated the presence of kaolinite, kaolinite and quartz and pirophylliteas the mains mineral constitution of the samples. The results of the adsorption study indicated that the three samples did not show a significant increase in CEC due to acid or thermal treatments. However, the sample that presented the highest kaolinite content and CEC showed an effective cost benefit for water treatment application with low energy and chemical reagents spending.

    Palavras-Chave: adsorption; clays; ion exchange; kaolin; kaolinite; methylene blue; methylene blue; titration

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  • IPEN-DOC 28510

    FREIRE, LUCIANO O. ; ANDRADE, DELVONEI A. de . Preliminary survey on cold fusion: it’s not pathological science and may require revision of nuclear theory. Journal of Electroanalytical Chemistry, v. 903, p. 1-10, 2021. DOI: 10.1016/j.jelechem.2021.115871

    Abstract: Since 1989 the announcement of “cold fusion” by Stanley Pons and Martin Fleishmann, “cold fusion” field has been surrounded by controversy. After three decades, this field is alive and has produced thousands of publications, most in dedicated periodic and conferences. This work aims at checking whether “cold fusion” fits in pathological science traits. For each type of experiment and year, this work counted the distinct research groups results (success or failure). Experimental results from many research groups suggest that nuclear reactions in solids are more complex than fusion (it is not only fusion) and that they need energy triggers like background radiation, meaning chemical configurations alone do not seem to generate nuclear reactions. Some types of experiments present rising trends (the field does not fit in pathological science model) and have potential to bring disruptive technologies. If confirmed, experimental results will require revisions of accepted nuclear models.

    Palavras-Chave: cold fusion; nuclear reactions; pathology; confinement; cavitation

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  • IPEN-DOC 28509

    PEREIRA FILHO, N.G. ; SOUZA, R.F.B. ; RAMOS, A.S. ; ANTONIASSI, R.M. ; OLIVEIRA NETO, A. ; SPINACE, E.V. . Electro-oxidation of ethanol in acid medium using carbon-supported PtRh nanoparticles with (100) preferential orientation. International Journal of Electrochemical Science, v. 16, n. 12, p. 1-13, 2021. DOI: 10.20964/2021.12.56

    Abstract: Carbon-supported PtRh nanoparticles with preferential (100) orientation was prepared by an alcohol-reduction process using KBr as a shape directing agent. The electrocatalysts were characterized by EDX (energy-dispersive X-ray analysis), XRD (X-ray diffraction) and TEM (Transmission electron microscopy). The electro-oxidation of ethanol was studied by cyclic voltammetry and chronoamperometry at room temperature in acid medium. On-line differential mass spectrometry experiments were performed on a single cell of a direct ethanol fuel cell (DEFC) at 60 0C and the anodic effluents were analyzed by ATR-FTIR. PtRh/C (100) electrocatalyst showed cubic-like morphology and average nanoparticles size of 8 nm and provided superior DEFC performance (density power per Pt active area) and CO2 selectivity compared to polycrystalline PtRh/C and commercial Pt/C electrocatalysts.

    Palavras-Chave: nanoparticles; platinum alloys; rhodium alloys; electrocatalysts; ethanol; fuel cells

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  • IPEN-DOC 28508

    OLIVEIRA, JOAO E. ; SUZUKI, MIRIAM F. ; DAMIANI, RENATA; LIMA, ELIANA R.; AMARAL, KLEICY C. ; SANTOS, ANDERSON M.S.; MAGALHAES, GERALDO S.; FAVERANI, LEONARDO P.; PEREIRA, LUIS A.V.D.; BARTOLINI, PAOLO . Synthesis of human bone morphogenetic protein-2 (hBMP-2) in E. coli periplasmic space: its characterization and preclinical testing. Cells, v. 10, n. 12, p. 1-16, 2021. DOI: 10.3390/cells10123525

    Abstract: Human BMP-2, a homodimeric protein that belongs to the TGF- family, is a recognized osteoinductor due to its capacity of inducing bone regeneration and ectopic bone formation. The administration of its recombinant form is an alternative to autologous bone grafting. A variety of E. coli-derived hBMP-2 has been synthesized through refolding of cytoplasmic inclusion bodies. The present work reports the synthesis, purification, and characterization of periplasmic hBMP-2, obtained directly in its correctly folded and authentic form, i.e., without the initial methionine typical of the cytoplasmic product that can induce undesired immunoreactivity. A bacterial expression vector was constructed including the DsbA signal peptide and the cDNA of hBMP-2. The periplasmic fluid was extracted by osmotic shock and analyzed via SDS-PAGE, Western blotting, and reversed-phase high-performance liquid chromatography (RP-HPLC). The purification was carried out by heparin affinity chromatography, followed by high-performance size-exclusion chromatography (HPSEC). HPSEC was used for qualitative and quantitative analysis of the final product, which showed >95% purity. The classical in vitro bioassay based on the induction of alkaline phosphatase activity in myoblastic murine C2C12 cells and the in vivo bioassay consisting of treating calvarial critical-size defects in rats confirmed its bioactivity, which matched the analogous literature data for hBMP-2.

    Palavras-Chave: bone tissues; proteins; plasmids; critical size; defects

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  • IPEN-DOC 28507

    DANTAS, A.C. ; SILVA, A.T. . A method for uncertainty and sensitivity analysis in fuel performance codes. Brazilian Journal of Radiation Sciences, v. 9, n. 3, p. 1-18, 2021. DOI: 10.15392/bjrs.v9i3.1700

    Abstract: The present study proposes a method for the execution of uncertainty and sensitivity analysis on TRANSURANUS code, adapted for the use of stainless steel AISI-348 as the cladding material for a PWR reactor fuel rod, thus allowing to determine which input data are more relevant to the TRANSURANUS models, as well as a confidence interval for the results. The analysis was made through Monte Carlo sampling, where input values related to the geometry and composition of the fuel rod were taken from a normal distribution truncated around fabrication tolerance values. The generated samples were used as TRANSURANUS input data, and after numerous executions of the code, the results pertaining to the fuel center line temperature, fuel rod inner pressure and cladding strains were used to obtain a confidence interval and to make a variance-based sensitivity analysis, showing that the models used in TRANSURANUS are additive in nature, and input interactions are not relevant to the code.

    Palavras-Chave: cladding; data covariances; fuel rods; monte carlo method; nuclear fuels; performance; pwr type reactors; sensitivity analysis; stainless steel-348; t codes

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  • IPEN-DOC 28506

    BEZERRA, ANDRE de S. ; ZEITUNI, CARLOS A. ; ROSTELATO, MARIA E.C.M. . Characterization of patients with prostate cancer care at a reference hospital in the state of Tocantins, suitable for brachytherapy. Brazilian Journal of Radiation Sciences, v. 9, n. 3, p. 1-15, 2021. DOI: 10.15392/bjrs.v9i3.1691

    Abstract: Observation and identification of predictive factors for results and morbidity are essential in the ideal selection of patients who can use brachytherapy as a treatment modality for prostate cancer. Thus, the objective of this research is to characterize the population of patients with prostate cancer treated at the General Public Hospital of Palmas in 2015, in the state of Tocantins. The method used was quantitative, with the characteristics of a retrospective, transversal and descriptive analysis. Held in the largest state health unit, the General Public Hospital of Palmas that, despite its large dimensions, lives with the main problems of the Unified Health System, such as overcrowding and shortages. It was found that most of the patients seen corresponded to the age of 70 to 79 years, making 45%, followed by patients aged between 60 and 69 years, with 33%. Most of the individuals attended were from the state of Tocantins, but some lived in an adjacent city in the state of Pará. Data related to the Gleason score showed that there was a predominance of levels 6 and 7 indicating intermediate grade tumors, considering that the most of the observed population was older. It was concluded that the analyzed patients had a predominant staging of CaP II and III, thus most of the individuals, 23 of the 35 analyzed, were not able to undergo brachytherapy due to the high degree of disease staging.

    Palavras-Chave: brachytherapy; carcinomas; disease incidence; elderly people; prostate; statistical data

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  • IPEN-DOC 28505

    GOMES, FERNANDA C.G.; NAURATH, CHRISTIAN; AZEVEDO, LUCIANE H.; ZEZELL, DENISE M. . Photobiomodulation therapy to treat neuropathic oral pain after contagion by COVID-19. Brazilian Dental Science, v. 24, n. 4, Suppl 1, p. 1-5, 2021. DOI: 10.4322/bds.2021.e2962

    Abstract: Objective: The purpose of this short communication is to show that although photobiomodulation in the treatment of neurophathic oral pain after COVID-19 contagion could be an option, photobiomodulation is not a new technique. PBMT was used with different protocols and pain was assessed using VAS (visual analogue scale - 0 until 10) before and after the consultation. Results: Evolution of VAS during the sessions showed a decrease in painful symptomatology as treatment was performed. Conclusion: Based on the results obtained in the present case report, we concluded that PBMT with the parameters used in this clinical case was an effective, noninvasive and a new option of treatment for neuralgia resulting from COVID-19.

    Palavras-Chave: light emitting diodes; therapy; coronaviruses; nerves; pain

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  • IPEN-DOC 28504

    SCARDINI, IANDARA de L.; ZEZELL, DENISE M. ; MARQUES, JULIANA L.C.; FREIRE, LAILA G.; SANTOS, MARCELO dos. Surface profile of different heat-treated nickel-titanium files before and after root canal preparation. Brazilian Dental Journal, v. 32, n. 6, p. 8-15, 2021. DOI: 10.1590/0103-6440202104045

    Abstract: The aim of this study was to evaluate surface wear, presence of microcracks and surface irregularities of WaveOne (WO) and WaveOne Gold (WOG) instruments before and after multiple uses. Eight Primary instruments of the WO and WOG systems were evaluated, each one was used to prepare six mesial canals of extracted human mandibular molars. The surface of the instruments was evaluated before use (T0), after instrumentation of three (T1) and six (T2) root canals. Surface wear was analyzed using a three-dimensional optical profiler and the presence of microcracks and surface irregularities were evaluated using a tabletop scanning electron microscopy. The Friedman test was used to assess surface wear and Kruskal-Wallis test to evaluate the presence of microcracks and surface irregularities, with a 5% significance level. There was a significant increase in wear in both groups at T2, compared to T0 (p=0.0003). The surface wear after instrumentation of six canals (T2-T0) was statistically greater in the WOG group, than in the WO group (p=0.02), where the presence of microcracks was significantly greater and increased after multiple uses (p<0.05). The presence of surface irregularities in the cutting blade before and after use was statistically greater in the WOG group than WO group (p<0.05). Wear of the cutting blade, microcracks and surface irregularities were observed on the surface topography of all the instruments after multiple uses. These surface changes may affect the cutting efficiency of WOG files and increase the risk of fracture of WO files.

    Palavras-Chave: nickel; titanium; dentistry; bone tissues

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  • IPEN-DOC 28503

    BASSO, LUANA S.; MARANI, LUCIANO; GATTI, LUCIANA V. ; MILLER, JOHN B.; GLOOR, MANUEL; MELACK, JOHN; CASSOL, HENRIQUE L.G.; TEJADA, GRACIELA; DOMINGUES, LUCAS G. ; ARAI, EGIDIO; SANCHEZ, ALBER H.; CORREA, SERGIO M.; ANDERSON, LIANA; ARAGAO, LUIZ E.O.C.; CORREIA, CAIO S.C. ; CRISPIM, STEPHANE P.; NEVES, RAIANE A.L.. Amazon methane budget derived from multi-year airborne observations highlights regional variations in emissions. Communications Earth & Environment, v. 2, n. 1, p. 1-13, 2021. DOI: 10.1038/s43247-021-00314-4

    Abstract: Atmospheric methane concentrations were nearly constant between 1999 and 2006, but have been rising since by an average of ~8 ppb per year. Increases in wetland emissions, the largest natural global methane source, may be partly responsible for this rise. The scarcity of in situ atmospheric methane observations in tropical regions may be one source of large disparities between top-down and bottom-up estimates. Here we present 590 lower-troposphere vertical profiles of methane concentration from four sites across Amazonia between 2010 and 2018. We find that Amazonia emits 46.2 ± 10.3 Tg of methane per year (~8% of global emissions) with no temporal trend. Based on carbon monoxide, 17% of the sources are from biomass burning with the remainder (83%) attributable mainly to wetlands. Northwest-central Amazon emissions are nearly aseasonal, consistent with weak precipitation seasonality, while southern emissions are strongly seasonal linked to soil water seasonality. We also find a distinct east-west contrast with large fluxes in the northeast, the cause of which is currently unclear.

    Palavras-Chave: methane; emission; ecological concentration; climates; amazon river

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  • IPEN-DOC 28502

    AZEVEDO JUNIOR, JAIR ; BARROSO, ANTONIO C. de O. ; MONTEIRO, CARLOS A. . An expedited model to appraise project management office value. International Journal of Development Research, v. 11, n. 12, p. 52699-52704, 2021. DOI: 10.37118/ijdr.23690.12.2021

    Abstract: This study presents the development of a practical model to evaluate the perception of Project Management Office value as seen by project managers. Questions compiled through literature review and interaction with project managers are presented first. An exploratory factor analysis was used to define the best grouping of the items within factors that could be interpretable under the reviewed literature. To evaluate the efficacy of the proposed model, we performed a confirmatory analysis using the Partial Least Square variant of the Structural Equation Modeling. The model demonstrated good convergent validity, very good discriminant validity, and reliability. In addition, the values of its determination and path coefficients were well above the classically recommended values and were also statistically significant. Within the limitations of the tests we done thus far, it appears that a practical, robust, and potentially functional predictive model was achieved.

    Palavras-Chave: program management; organizational models; cost; planning

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  • IPEN-DOC 28501

    ALMEIDA, JORGE V. de; GU, XIAOQIANG; MOSSO, MARBEY M.; SARTORI, CARLOS A.F. ; WU, KE. Nonlinear metamaterial lenses for inductive power transmission systems using Duffing-resonator based unit cells. J, v. 4, n. 4, p. 727-748, 2021. DOI: 10.3390/j4040050

    Abstract: Metamaterials (MTMs) based on a periodic array of resonant coils have been shown to behave as μ-negative (MNG), enabling the focusing of magnetic flux. The phenomenon has been deployed by designers to boost the efficiency of many inductively coupled systems, such as magnetic resonance imaging, underwater and underground communications, and charging base stations (CBS) for consumer electronics and implanted devices. However, due to their dependency on high-Q unit cells, linear MNG-like MTMs have limited bandwidth, restricting their use in many applications, notably in near-field simultaneous wireless information and power transmission (NF-SWIPT) systems. To improve the tight constraints of the amplitude-bandwidth trade-off of artificial magnetic lenses, this paper presents a theoretical analysis of nonlinear MTMs based on a lattice of Duffing resonators (DRs). Additionally, it introduces a criterium for the quantification and evaluation of the amplitude-bandwidth enhancement. The analytical results are based on a circuit model and further verified by numerical simulations using commercial software. The preliminary findings in this paper open up possibilities for nonlinear MTM lenses and can be applied to enhance the linear amplitude-bandwidth limit.

    Palavras-Chave: metamaterials; resonators; electromagnetic lenses; power transmission

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  • IPEN-DOC 18922

    GOTTARDI, MARIELLA da S. ; KAWAMOTO, DIONE; ZAMATARO, CLAUDIA B. ; ANA, PATRICIA A. da ; MAYER, MARCIA P.A.; ZEZELL, DENISE M. . In vivo study of diode laser 940 nm operating in high intensity mode in the periimplantitis disease. In: LASER DENTISTRY WORLD CONGRESS, 16th; DGL ANNUAL MEETING, 27th; INTERNATIONAL WALED CONGRESS, 6th, October 1-3, 2018, Aachen, Germany. Abstract... Aachen, Germany: International Society for Laser in Dentistry, 2018. p. 62-62.

    Abstract: The evolution of periimplantitis has been associated with several risk factors. The standard treatment consists on subgingival scaling and blasting with sodium bicarbonate. This 6 months longitudinal clinical study evaluated and compared two treatment methods: conventional as described and complemented by irradiation with high intensity diode laser (940 nm, Biolase) aiming to establish a more efficient periimplantitis management. After approval by the Human Research Ethics Committee, 20 patients of both sexes, with implants in function for at least 12 months and with diagnosis of periimplantitis were selected and randomly distributed in two experimental groups. Ten of them were conventionally treated as control group, and the remaining ten were in the laser treated group (1W, 4.24kJ/ cm2 energy density, pulsed mode, 30s, twice). There were six sites for treatment standardization: vestibular region (mesial, central and distal thirds) and buccal region (mesial, central and distal thirds). Results has shown that overall clinical evaluation has no significant difference between groups control and treatment. less bleeding and suppuration, as shallower periodontal pocket indicated a decreasing tendency on laser treated group. Quantitation of total bacteria and Porphyromona gingivalis by real-time PCR shown that laser synergy is a complementary therapy that could act as an additional option to the conventional treatment in difficult response cases.

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  • IPEN-DOC 18813

    MORAES, MARCIA C.D. ; PEREIRA, DAISA L. ; ZAMATARO, CLAUDIA B. ; ZEZELL, DENISE M. ; FREITAS, ANDERSON Z. . Effect of Nd:YAG laser on caries prevention of dental enamel by optical attenuation coefficient with optical coherence tomography (OCT). In: LASER DENTISTRY WORLD CONGRESS, 16th; DGL ANNUAL MEETING, 27th; INTERNATIONAL WALED CONGRESS, 6th, October 1-3, 2018, Aachen, Germany. Abstract... Aachen, Germany: International Society for Laser in Dentistry, 2018. p. 48-48.

    Abstract: Caries is a multifactorial disease, caused by the continuing loss of hydroxyapatite crystals. The association of topical acidulated phosphate fluoride application (APF) and high intensity lasers has the potencial to increase the resistance to demineralization of dental tissues. The Nd:YAG laser, specially associated to a photoabsorber over the dental surface, may induce thermal changes in order to increase the resistance to demineralization. Optical Coherence Tomography (OCT) is a non-ionizing radiation imaging technique that can be performed in real time in vivo and can detect early changes in the optical properties of t issues. This study aimed to characterize the effectiveness of the association of Nd:YAG la ser and APF gel in the prevention of caries lesions in human dental enamel in vitro, due to structural changes in function of the pH cycling, the treatments performed as well as to evaluate the potential of OCT to diagnose early demineralization. 160 human enamel samples were divided in four groups and submitted to pH cycling during 20 days, after the following treatments: G1- untreated; G2- treated with APF gel (1.23% F-, 4min); G3- irradiated with Nd:YAG (1064nm, 84.9J/ cm2, 10Hz) followed by APF application and G4- APF application before Nd:YAG laser irradiation (same conditions of G3). OCT (930 nm) analysis were performed before and after the treatments, 5th, 10th, 15th and 20th day of pH cycling. The optical attenuation coefficient decreased significantly (p<0.05) as demineralization increased over time and better results were achieved in group G4. OCT technique can diagnose early demineralization in enamel.

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  • IPEN-DOC 18688

    PEREIRA, DAISA L. ; MORAES, MARCIA C.D. ; ZAMATARO, CLAUDIA B. ; ZEZELL, DENISE M. . Longevity of diode laser irradiation in dentine: an in vitro study. In: LASER DENTISTRY WORLD CONGRESS, 16th; DGL ANNUAL MEETING, 27th; INTERNATIONAL WALED CONGRESS, 6th, October 1-3, 2018, Aachen, Germany. Abstract... Aachen, Germany: International Society for Laser in Dentistry, 2018. p. 47-47.

    Abstract: The efficacy of pulsed infrared lasers on clinical dentin wear sensitivity is well stablished in the Literature. This work aims to evaluate the effect of diode laser combined with fluoride products regarding the longevity of the sensibility treatment under the effect of the domestic use products. After Ethics Committee approval, 75 slabs of bovine root dentin measuring 8 mm2, were randomized into 5 groups (n=1 5): G1- untreated; G2- treated with acidulated phosphate fluoride (APF-gel, [F-J=1.23 %, pH=3.3 to 3.9); G3- irradiated with diode laser (980 nm, 2.5W, 5ms, 25Hz) using a cool paste as photoabsorber; G4- irradiated with diode laser (same conditions of G3) using a coal paste as photoabsorber + application of APF-gel and G5- application of APF-gel+ diode laser irradiation (same conditions of G3). All samples were submitted to an erosive and abrasive demineralization (Sprite Zero, pH=2.8, 90s, 4x/day), and remineralization (artificial saliva, pH=7.4) cycling for 10 days. Twice a day, slabs were brushed for 15s using a whitening dentifrice (Sensodyne True White, GSK, EUA). Slabs were evaluated by Optical Coherence Tomography (OCT) at the initial and 7th day of cycling. OCT measurements found a significant increase on dentin wear depth and area of lesions with the increase of cycling days. G1 and G2 hod significant higher mineral loss compared to the other groups. G3, G4 and GS showed no significant differences between them. Results suggested that the sensibility of the treatment with the diode laser has longevity despite the high abrasivity of dentifrice used in maintenance.

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  • IPEN-DOC 18613

    ZAMATARO, CLAUDIA B. ; PEREIRA, DAISA de L. ; LIMA, CASSIO A. ; SCAPIN, MARCOS A. ; ZEZELL, DENISE M. . Gamma sterilized human dental enamel submitted to Er,Cr: YSGG laser irradiation associated to fluoride for in situ model. In: LASER DENTISTRY WORLD CONGRESS, 16th; DGL ANNUAL MEETING, 27th; INTERNATIONAL WALED CONGRESS, 6th, October 1-3, 2018, Aachen, Germany. Abstract... Aachen, Germany: International Society for Laser in Dentistry, 2018. p. 89-89.

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  • IPEN-DOC 18533

    BEZERRA, SAVIO J.C.; TREVISAN, LETICIA R.; VIANA, ITALLO E.L.; LOPES, RAQUEL M.; PEREIRA, DAISA de L. ; SAKAE, LETICIA O.; ARANHA, ANA C.C.; SCARAMUCCI, TAIS. Er,Cr:YSGG laser associated to fluoride on the control of dentin erosion progression. In: LASER DENTISTRY WORLD CONGRESS, 16th; DGL ANNUAL MEETING, 27th; INTERNATIONAL WALED CONGRESS, 6th, October 1-3, 2018, Aachen, Germany. Abstract... Aachen, Germany: International Society for Laser in Dentistry, 2018. p. 88-88.

    Abstract: 1) Introduction: The combination between high power lasers and fluoride may potentially control the progression of dentin erosion. Therefore, the aim of this study was to evaluate the effect of Er,CrYSGG laser, associated to fluoride application, in the control of dentin erosion. 2) Materials and Methods: Dentin slabs were embedded into acrylic resin, flattened and polished. The specimens (n=10) were previously eroded (10min immersion in 1% citric acid solution) and randomly allocated into the experimental groups, according to the following treatments: control (no treatment); acidulated phosphate fluoride (APF) gel (1.23% F, 1min); Er,Cr:YSGG laser irradiation (parameter 1: 0.25W, 20Hz, 2.8J/cm2); Er,Cr:YSGG loser irradiation (parameter 2: 0.50W, 20Hz, 5.7J/cm2); APF gel+Er,Cr:YSGG laser parameter 1 and; APF gel+Er,Cr:YSGG laser parameter 2. After, they underwent on erosion-remineralization cycling, consisting of a 5min immersion into 0.3% citric acid, followed by 60min exposure to artificial saliva. This procedure was repeated 4x/day, for 5 days. Surface loss (SL, in μm) was determined with optical profilometry. The specimens were analyzed by environmental scanning electron microscopy (n=3). Data were statistically analyzed (α=0.05). 3) Results: None of the groups significantly differed from the control group, except for the APF group. APF gel presented the lowest SL, not differing from Er,Cr.YSGG laser (parameter 1) and APF gel+Er,Cr:YSGG laser (parameter 1). Selective structure removal was observed for the laser-treated groups. 4) Conclusions: None of the Er,Cr:YSGG laser parameters were effective in the control of dentin erosion. The laser was also not able to enhance the protection of fluoride against dental erosion.

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  • IPEN-DOC 18453

    YOSHIKAWA, HELENICE Y.; DAGUANO, JULIANA K.M.B.; PEREIRA, DAISA L. ; ZEZELL, DENISE M. ; ANA, PATRICIA A. . Effects of Er,Cr:YSGG laser and a bioactive glass on root caries remineralization. In: LASER DENTISTRY WORLD CONGRESS, 16th; DGL ANNUAL MEETING, 27th; INTERNATIONAL WALED CONGRESS, 6th, October 1-3, 2018, Aachen, Germany. Abstract... Aachen, Germany: International Society for Laser in Dentistry, 2018. p. 87-88.

    Abstract: Considering the aging of the population, the greater exposure of the root surfaces and the higher caries risk in these surfaces, the development of strategies that efficiently remineralize root caries lesions in a long-lasting way is strictly necessary. This in vitro blind randomized study evaluated the potential of remineralization of root caries lesions promoted by Er,Cr:YSGG laser irradiation (2.78 μm) associated with a bioactive glass (Biosilicate ®). 60 bovine root dentin slabs with incipient caries lesions were distributed in 6 experimental groups {n:::15l, in order to be treated with laser irradiation (0.25W, 12.5 mJ/pulse, 2.8 J/cm2, 20 Hz, without refrigeration), application of Biosilicate® or association of both. After the treatments, the samples were subjected to an 8-day pH-cycling regimen, and further evaluated by Fourier transformed infrared spectroscopy {FTIR), optical coherence tomography (OCT) and scanning electron microscopy. The data were statistically analyzed at a 5% significance level. The Biosiljcate ® promoted the formation of carbonated hydroxyapatite even before loser irradiation, which was better retained after demineralization in loser irradiated group. The Biosilicote® and the la ser irradiation alone provided the remineralization of the root dentin in a similar way to that promoted by the topical application of acidulated phosphate fluoride, since all groups had comparable optical attenuation coefficients. The association of the Biosilicate® with the loser irradiation showed higher optical attenuation coefficient than the other experimental groups. It was concluded that the association of Biosilicote® with laser irradiation promoted a synergistic effect, augmenting the remineralization of root dentin and preventing the progression of caries.

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  • IPEN-DOC 18341

    PEREIRA, DAISA L. ; GOMES, GABRIELA V. ; SUGAHARA, VANESSA M.L.; SCAPIN, MARCOS A. ; ANA, PATRICIA A. ; ARANHA, ANA C.C.; ZAMATARO, CLAUDIA B. ; ZEZELL, DENISE M. . Nd:YAG laser irradiation of darkened dental enamel by means of dentrifice use. In: LASER DENTISTRY WORLD CONGRESS, 16th; DGL ANNUAL MEETING, 27th; INTERNATIONAL WALED CONGRESS, 6th, October 1-3, 2018, Aachen, Germany. Abstract... Aachen, Germany: International Society for Laser in Dentistry, 2018. p. 87-87.

    Abstract: As the world population is growing older, dental erosion became a real concern on dentistry. Optical Coherence Tomography and X-Ray fluorescence were used to analyze enamel samples covered by black dentifrice as photoabsorber irradiated with NdYAG laser, then submitted to an erosive cycling. Heat injury risk in deeper tissue decreases because of the dentifrice dark pigment, when the most of photons are absorbed in the surface. Sixty Bmm2 blocks of bovine enamel, were randomized into 4 groups: G1- untreated; G2- treated with acidulated phosphate fluoride (APF, [FJ::1.23%, pH::3.3 to 3.9); G3- irradiated with Nd:YAG laser (1064nm, 0.6W, 10Hz- Lares Research®) using a coal paste as photoabsorber; G4- irradiated with Nd:YAG laser (1064nm, 0.6W, 10Hz), using a black dentifrice (Black is White, Curaprox®). All samples were submitted to a 3-day erosive demineralization (Citric acid 1%, pH::3.6, 5min, 2x/day) under agitation, and remineralization cycling (artificial saliva, pH::7, 120minJ. After treatments and pH cycling, the [Ca]/[P] ratio decreased in the laser irradiated groups. The samples were evaluated by OCT before and after treatment and after erosive cycling. OCT measurements found smaller lesion depths in laser irradiated groups than in the other groups and there were statistically significant differences between G3 and G4 groups (p<0.05). Heating promoted by Nd:YAG laser irradiation changed the morphological and crystallographic enamel surface properties and has shown to be a promissory alternative to prevent erosion.

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  • IPEN-DOC 17850

    LOPES, MONICA S.; PEREIRA, DAISA L. ; MOTA, CLAUDIA C.B.O.; ANA, PATRICIA A. ; ZEZELL, DENISE M. ; GOMES, ANDERSON S.L.. Shear bond strength of lingual brackets on enamel surface submitted to acid-etching or Nd:YAG laser irradiation. In: LASER DENTISTRY WORLD CONGRESS, 16th; DGL ANNUAL MEETING, 27th; INTERNATIONAL WALED CONGRESS, 6th, October 1-3, 2018, Aachen, Germany. Abstract... Aachen, Germany: International Society for Laser Dentistry, 2018. p. 82-82.

    Abstract: The patient demand for aesthetic orthodontic solutions is driving for use of lingual brackets and laser irradiation can prevent dental caries in this region. This in vitro study is the first one in literature that aimed to quantify the shear bond strength (SBS) on direct lingual b rackets bonding after different enamel surface pre-treatments. 75 bovine incisor teeth were randomized in 5 groups (n=15): G1- untreated; G2- treated with acidulated phosphate fluoride gel (APF-gel, [F-] =1.23%, pH=3.3 to 3.9); G3- conditioned with 37% phosphoric acid (Condoc 37%, FGM, Brazil) and treated with APF-gel; G4- irradiated with Nd:YAG loser (1064nm, 0.6W, 10Hz- Laser Research) and treated APF-gel; GS- irradiated with Nd:YAG laser + conditioned with 37% phosphoric acid + treated with APF-gel. The positioning of the brackets was standardized during the bonding procedure using a positioner and Transbond XT adhesive (3M Unitek, USA) was used. After bonding, all samples were thermocycled (500 cycles between SoC and 55°C) and submitted to a 48h cariogenic challenge. After cycling, the samples were tested for shear bond strength (SBS) in a universal testing machine (0.5mm/min). SBS test values were statistically higher (p<0.05) in the G3 and G5 groups when compared to the other groups. This study showed that the Nd:YAG loser irradiation improved dental adhesion and increased the mechanical resistance of the enamel because the heating promoted by Nd:YAG laser irradiation changed the morphological and crystallographic properties of enamel; in this way, this treatment also offers the advantage to prevent caries around brackets.

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  • IPEN-DOC 14839

    HARAGUCHI, MARCIO I.; KIM, HAE Y.; SPRENGER, FRANCISCO E. ; CALVO, WILSON A. P. . Imaging technique for troubleshooting of industrial equipment by gamma-ray absorption scans. In: DUDALA, JOANNA (Ed.); STEGOWSKI, ZDZISLAW (Ed.) INTERNATIONACONFERENCE ON DEVELOPMENT AND APPLICATIONS OF NUCLEAR TECHNOLOGIES, September 11-14, 2011, Krakow, Poland. Abstract... Krakow, Poland: Faculty of Physics and Applied Computer Science, AGH University of Science and Technology, 2011. p. 135-135.

    Abstract: Gamma scanning is one of the most common nuclear techniques on troubleshooting industrial equipments like distillation columns and reactors. With a very simple concept, the technique is easy to implement. Searching for a competitive edge the industry has been long developing solutions to achieve better results. On the last decades, significant development has been done with the advent of new equipments, electronics, portable computers and software, to the point that nowadays the field work and reporting can be done in a question of hours. Continuous scanning and wireless detection systems are examples of successful field solutions, while new software aid on reporting and data presentation. However the type and quality of the results itself has not dramatically changed since its beginning. A scan profile is simple to understand, although the process to build it can be very complex as it requires a specific blend of knowledge and abilities. Process Engineering, Chemical Engineering, Internal Hydraulic Project, Nuclear Engineering and field abilities are pre requisites for of any scan specialist rookie. Correct data gathering, interpretation and reporting are abilities often difficult to match or requires a long time of training. Probably there are no more than a handful of scan specialists on the world. The industry faces a similar difficult on the customer side, as it is always necessary to train end users to understand a report and how to use its best. This paper describes our effort on developing a new approach on the gamma scan test using image reconstruction techniques that would result on a graphic image rather than a XY plot. Direct and easier to understand, a report with graphic images would be also accessible to a wider audience, not limited to the customers experienced with gamma scan interpretation.

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  • IPEN-DOC 17421

    FEIST, I.; ANDRADE, A.K.P.; DE MICHELI, G.; CAI, S.; PANUTTI, C.; ZEZELL, D. ; EDUARDO, C.P.. Bacterial reduction in class II furcation after root debridment with or without Nd:YAG laser irradiation. In: LASER CONGRESS; CONGRESS OF THE EUROPEAN SOCIETY FOR ORAL LASER APPLICATIONS, 3rd; CONGRESO DE LA SOCIEDAD ESPANOLA DE LASER ODONTOESTOMATOLOGICO, 6th; CONGRESSO DELLA SOCIETA ITALIANA DI LASER IN ODONTOIATRIA, 4th, May 19-21, 2005, Barcelona, Spain. Abstract... Vienna, Austria / Barcelona, Spain: European Society for Oral Laser Applications - ESOLA / Sociedad Española de Láser Odontoestomatológico - SELO, 2005. p. 14-15.

    Abstract: The use of Nd:YAG laser for bacterial reduction as an adjuvant to non-surgical periodontal treatment has been approached in several studies. Furcation complex anatomy is responsible for comprised treatment results in this areas due to the lack of proper access for instrumentation showing the persistence of a pathogenic microbial flora. The purpose of this clinical trial, randomized, double-blinded was to evaluated the bacterial reduction achieved with the Nd:YAG laser associated to conventional treatment on furcation sites of 17 patients with chronic periodontitis. They received previous full mouth periodontal treatment except for the experimental sites. In a split mouth design study, 34 class 11 furcations were selected and divided in two groups. The 17 furcations of the control group underwent twice manual and ultrasonic root debridment in weekly intervals. The test group received the same treatment as the control group followed by the Nd:YAG laser application (100 mJ/pulse, 1.5 W, 15 Hz, 60 see.). The microbiological parameters - total number of anaerobic Colony Forming Units (CFU), Black pigmented CFU and the level of A. actinomycetemcomitans, P. gingivalis and P. intermedia - were determined at baseline. immediately and one month after the treatment. The results showed a significant reduction of total CFU for both groups immediately after treatment, but it was better for the test group. After one month the total CFU average increased but was still below pretreatment levels for both groups. The Black pigmented CFU and the level of A. actinomycetemcomitans. P. gingivalis and P. intermedia decreased significantly after the treatment but 30 days after. there was an increase almost equal to baseline levels for both groups. The Nd:YAG laser associated with conventional treatment promoted bacterial reduction on class II furcation immediately after its application.

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  • IPEN-DOC 14692

    MARQUES, M.M.; HAYPEK, P.; EDUARDO, F.P.; MIGLIORATI, C.A.; ZEZELL, D.M. ; EDUARDO, C.P.. Effect of high intensity diode laser irradiation on growth of human gingival fibroblasts. In: LASER CONGRESS; CONGRESS OF THE EUROPEAN SOCIETY FOR ORAL LASER APPLICATIONS, 2nd; CONGRESSO DELLA SOCIETA ITALIANA DI LASER IN ODONTOIATRIA, 2nd, May 15-18, 2003, Florence, Italy. Abstract... Vienna, Austria / Roma, Italy: European Society for Oral Laser Applications - ESOLA / Società Italiana di Laser in Odontoiatria - SILO, 2003. p. 38-38.

    Abstract: Purpose: Diode lasers present some advantages over the other surgical lasers. The equipments are more compact and can also be used in low intensity laser therapy. The aim of this study is to analyze a possible biostimulatory effect of the diode laser on human cultured gingival fibroblasts. Material and Methods: The celll ine FMM1 was grown in Dulbecco' modified Eagle medium. Laser irradiation was carried out with a GaAIAs diode laser (wavelength: 808 nm, power output: 3.5 W, Zap Lasers, CA, USA). The irradiation was done in a defocused and continuous wave mode using a fiber of 400 micrometers. The experiments were done in triplicate (Group 1: non-irradiated cells; Group 2: cells irradiated with 3 J/cm2; and Group 3: cells irradiated with 4 J/cm2). The data of the growth curves were analyzed by statistical means. Results and Conclusion: The defocused diode laser irradiation used as low intensity laser therapy presents biostimulatory effect on growth of human gingival fibroblasts.

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  • IPEN-DOC 14592

    SUZUKI, L.C.; YAMADA JUNIOR, A.M. ; HAYEK, R.R.A.; RIBEIRO, M.S. . A case report of photodynamic therapy on bacterial reduction before immediate implant. Brazilian Dental Journal, v. 15, Special issue, p. 127-127, 2004.

    Abstract: Recent studies have demonstrated that a number of oral bacteria can be killed by photodynamic therapy with low concentrations of dyes. Photodynamic therapy is the combination of light with appropriate wavelength and a photosensitizer. The antimicrobial activity is mainly mediated by singlet oxygen and/or free radicals generated by the photoactivated sensitizer. A flap surgery aiming an immediate implant was made in a residual root with periodontal lesion on upper first premolar. After the extraction, a microbiological sample with sterile paper points was harvested. Then, the photosensitizer was applied in the infected alveolus and irradiated with low-intensity laser, ?= 660 nm, P= 30 mW and E= 9 J . After the photodynamic therapy, a new microbiological sample was harvested. Subsequently, it was prepared the implant bed with conical burs and then the implant was placed. Patient was medicated with antibiotic after surgery. The microbiological analysis showed a significant reduction of Prevotella sp., Fusobacterium sp. and Streptococcus beta-hemoliticus. This finding suggests that photodynamic therapy is an alternative method to disinfect alveolus before implant placement. Therefore, this study highlights the need for future work in the area of photodynamic therapy to reduce bacteria without harming host tissue.

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  • IPEN-DOC 14214

    NAKASONE, R.K.; RODRIGUES, C.R.M.D.; BUZALAF, M.A.R.; OLYMPO, K.P.K.; TANJI, E.Y.; RIBEIRO, M.S. . Effects of the low-intensity red laser radiation on the fluoride uptake in human enamel: a preliminary study. Brazilian Dental Journal, v. 15, Special issue, p. 119-120, 2004.

    Abstract: Fluoride has been the most important preventive method on development of the caries. This in vivo study evaluated the effects of lowintensity red laser radiation on the fluoride uptake in enamel. Ten healthy participants were recruited for this study. The two upper central incisors of each volunteer were used and divided into 4 groups: group GC (control), which was untreated; group GF (fluoride), which received topical acidulated phosphate fluoride (APF) 1,23% treatment for 4 minutes; group GLF (laser + fluoride), which was irradiated with a low-intensity diode laser (l= 660 nm and dose= 6 J/cm²) with APF application after irradiation and group GFL (fluoride + laser), which received APF before irradiation using the same parameters as GLF. The determination of fluoride was performed using a fluoride ion electrode after an acid-etch enamel biopsy. The results showed a significant increase of the fluoride uptake in enamel for groups GF, GLF and GFL when compared to control group. Although a percentage increase of 57% was observed for GLF with respect to GF, there were no statistical differences among the treated groups. These findings motivate further studies in order to introduce low-power laser associated to APF as a protective method of dental caries.

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  • IPEN-DOC 14036

    MULLER, K.P. ; YAMADA JUNIOR, A.M. ; SUGAYAMA, S.T.; RIBEIRO, M.S. . Local Treatment using high and low-power laser on herpes simplex. Brazilian Dental Journal, v. 15, Special issue, p. 119-119, 2004.

    Abstract: Herpes simplex (HSV) is commonly encountered in the dentistry practice disappearing after 10 to 14 days. Recently alternative treatments have been introduced, among those laser therapy. The aim of this study is to evaluate the efficacy of laser therapy in patients with perioral herpes simplex infection. A 32 years old female was treated with high-intensity laser therapy (HILT) in vesicle phase using a Nd:YAG laser, l= 1064 nm, P= 1,5 W, f= 15 Hz on days 1 and 2 to drainage the vesicles. Low-intensity laser therapy (LILT) was applied on the affected area in the 3 consecutive days with a GaAlAs laser, l= 830 nm, D= 5 J/cm2. On the other hand, a 7 years male patient, which presented the vesiculo-ulcerative stage, only LILT (l= 660 nm, D= 4 J/cm2) was carried out. For both cases, it was observed that the course of the infection was quicker than the normal. Seven days after treatment beginning the lesions were healed. These findings suggest that LILT associated or not to HILT is a efficient and promising treatment for HSV. Further larger studies aiming at confirming these data and investigating the LILT mechanisms of action should be performed.

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  • IPEN-DOC 13067

    LOLLATO, R.F.; GROTH, E.B.; RIBEIRO, M.S. . Low-intensity laser therapy and functional orthopedics in the treatment of pain from temporomandibular disfunction. Brazilian Dental Journal, v. 15, Special issue, p. 114-114, 2004.

    Abstract: Temporomandibular Disfunction (TMD) is a term used to describe disorders, which involve temporomandibular joint (TMJ), masticatory muscles, and associated structures, isolated or not, whose most frequent symptom is pain. The aim of this study was to evaluate pain and buccal mobility in subjects with Cl II malocclusion and TMD symptoms, treated with low-intensity laser therapy (LILT) and functional orthopedics (FO), associated or not. Eighteen subjects were selected and divided into three groups. Group 1 was treated with LILT, l = 780nm, 70 mW, 15 J/cm2 per point during two weeks. The application was in three points around the TMJ, and trigger points of masticatory muscles. Group 2 received Planas functional appliances and it was evaluated once a week during two weeks. Group 3 received both treatments at the same time, and the first laser application coincided with the appliance installation. Subjects answered a questionnaire with a score for pain evaluation after palpation. There was pain relief for the 3 groups and no statistical differences were observed among them, however, group 3 showed a remission of pain faster than other groups. This finding indicates the association of the LILT with FO for pain relief in TMD.

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  • IPEN-DOC 13052

    KOHARA, E.K. ; KATO, I.T.; WETTER, N.U. . Effects of 960nm diode laser irradiation and fluoride on calcium solubility of dental enamel in vitro. Brazilian Dental Journal, v. 15, Special issue, p. 112-112, 2004.

    Abstract: The aim of this study is to determine the effects of diode laser (?=960 nm) irradiation on calcium solubility of dental enamel. Sixty enamel specimens were prepared from human teeth and divided into four groups (control, fluoride, laser and fluoride plus laser). Prior to the irradiation a vegetable coal diluted in physiological solution was applied to the enamel surface and the specimens were irradiated using 6,5 W of peak power, 5 ms of pulse duration, 10 Hz of repetition rate, fluency of 3,7 J/cm2 and time exposure of 10 seconds. The acidulated phosphate fluoride was applied for 4 minutes. Next, the specimens were immersed in lactic acid for 24 hours at 37 °C. The calcium content in demineralization solution was evaluated with Inductively Coupled Plasma Atomic Emission Spectrometry. The results indicate an increase in calcium solubility (12%) after laser irradiation, however, not statistically significant. When associated with fluoride, the decrease in calcium solubility did not differ from the results obtained with fluoride only. It can be concluded that in this experiment diode laser irradiation did not increase acid resistance of dental enamel.

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  • IPEN-DOC 13050

    KOHARA, E.K. ; WETTER, N.U. ; RATTICHIERI, F.; KATO, I.T.. Microhardness of the dental enamel surface after irradiation with 960nm diode laser. Brazilian Dental Journal, v. 15, Special issue, p. 111-112, 2004.

    Abstract: Several authors analyzed laser irradiation of dental enamel in an attempt to increase acid resistance and achieve caries prevention. In some cases, the procedure has also been associated to the application of a layer of fluoride. Micro-hardness measurements are reliable tests used to determine the degree of resistance to demineralization. In this work micro-hardness values of superficial dental enamel have been measured before and after irradiation with a 960 nm diode laser, using tested laser parameters that are safe and cause no injuries to the adjacent tissue. Laser parameters were below the dental enamel ablation threshold. 60 enamel samples were used and divided into control group (GC), fluoride application (GF), laser irradiation (GL), fluoride application with subsequent laser irradiation (GFL) and laser with subsequent fluoride application (GLF). A solution containing coal was used on the enamel surface in order to absorb the laser radiation. A statistically significant loss of the micro-hardness value was obtained for all groups except for GL but also this group did not produce significant micro-hardness increase. Conclusion: at the current peak power and beam quality of standard diode laser bars, safe laser parameters do not produce higher micro-hardness values.

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  • IPEN-DOC 13014

    CAMARGO, A.; BALDOCHI, S. ; CAMARGO, S.; EDUARDO, C.P.. "In vitro" evaluation of morphologic changes on the root dentine irradiated by CO2 laser associated or not to calcium hydroxide. Brazilian Dental Journal, v. 15, Special issue, p. 102-103, 2004.

    Abstract: This in vitro study has evaluated the structural changes on the root dentine irradiated by a CO2 laser associated or not to calcium hydroxide - an alternative method for dentine hypersensitivity treatment. Fourteen human teeth 3rd molars were utilized, divided into 7 groups. Group I (control group),Groups II, III and IV received an application of Ca (OH)2 paste followed by CO2 laser irradiation for 5 seconds, intervals of 10 seconds, continuous emission, power of 0.5W, constant distance of 30mm (Group II), 1.0W (Group III), 1.5W (Group IV); Groups V, VI, VII received laser irradiations following the same parameters applied to groups II, III, and IV. Morphologic changes suggesting to fusion and re-solidification were observed, and the presence of material obstructing the whole analyzed surface on groups II, III, and IV. For groups V, VI, and VII, fusion, re-solidification, and cracks, were observed, results statistically significant (P<0,01). No statistically significant differences were observed in groups that used the same treatment. Powers above 1.0W (DP=125,38W/cm2) showed carbonization and dark surface, results unfavorable due to the undesirable morphologic alterations and aesthetic compromising.

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  • IPEN-DOC 13005

    ARCHILLA, J.R.F.; TANNOUS, J.T.; PELINO, J.E.P.; FREITAS, P.M.; SILVA, D.F.T.; RIBEIRO, M.S. . Spectroscopic analysis and interaction of different bleaching agents with 660n laser and 470 nm LED. Brazilian Dental Journal, v. 15, Special issue, p. 100-100, 2004.

    Abstract: The aim of this in vitro study was to verify the effect of different dental bleaching methods regarding the achromatic enamel color change. Forty-five bovine teeth were immersed in a darkening solution and then divided into nine experimental groups with five samples in each group. The color measurement was initially taken using a digital colorimeter. The teeth were submitted to the bleaching with three bleaching gels, without any activation source (control) and with two wavelengths (660 nm diode laser and 470 nm LED). The previous analysis of the absorption spectra enabled the choice of an adequate wavelength in order to enhance its photochemical action. The second color measurement was taken after all the treatments. The data were submitted to ANOVA and Tukey parametric statistical tests (p=0,05). It was observed that: 1) there was a statistical significant difference between the activation sources; 2) there was statistical significant difference regarding the interaction among the activation sources and the bleaching gels when compared with each other. The activation methods of the bleaching agents, even promoting color changes in distinct levels, still require further studies capable of detecting a higher absorption spectrum of a product and which presents significant clinical results.

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  • IPEN-DOC 13002

    TODESCAN, C.D.R.; VIEIRA JUNIOR, N.D. ; SAMAD, R.E. ; FREITAS, A.Z. ; EDUARDO, C.P.. Ultrashort pulses over bovine dental enamel. Brazilian Dental Journal, v. 15, Special issue, p. 91-91, 2004.

    Abstract: The interaction of lasers with the hard structures of the teeth, has found the excess of heat as a problem for its utilization. This study analyzes, in vitro, the interaction of the ultrashort pulse laser of Ti:safire (830 nm) with the bovine dental enamel. The system consisted in one main oscillator integrated with an amplifier (CPA). The pulses extracted before the temporal compression inside the amplifier had 30ps, 1000Hz and ~1mJ. The pulses extracted after the compression had 60fs, 1000Hz and ~0,7mJ. The M2 was 1,3, the focal lens 2,5 cm, the focal distance 29,7 and a computadorized translation stage x,y,z moved the sample. We evaluated the amount of tissue removed per pulse,the resulting cavities and the surrounding tissues not irradiated, under OM and SEM. The fluency was the major factor for differentiating the two regimens studied, therefore, the intensity was not so important as we expected in this process. We found: one ablation region in "cat tonge", one ablation length, one fluency ~0,7J/cm2 for 30ps and ~0,5J/cm2 for 60fs (50% ofhigh speed burr), smooth edge for 30ps and high precision of the shrp edge cut of submicrometric order for 60fs.

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  • IPEN-DOC 12992

    GODOY, B.M.; ARANA-CHAVEZ, V.E.; BORTOLI GROTH, E.B.; RIBEIRO, M.S. . Effects of low-intensity red laser radiation on the dentine-pulp interface after class I cavity preparation disfunction. Brazilian Dental Journal, v. 15, Special issue, p. 86-87, 2004.

    Abstract: The aim of this study was to investigate the effects of low-intensity red laser radiation on the ultrastructure of dentine-pulp interface after conventionally prepared class I cavity preparation. Eight premolars indicated for extraction for orthodontic reasons from 2 patients were used. Class I cavities were prepared and the teeth were divided into two groups. The first group received a treatment with a GaAlAs laser, l= 660 nm, P= 30 mW and D= 2J/cm2. The laser tip was applied directly and perpendicularly into the cavity in only one sense. The teeth from the second group had their class I cavities prepared but they did not receive the laser therapy. All cavities were filled with composite resin. Twenty-eight days after the preparation, the teeth were extracted and processed for transmission electron microscopy analysis. Two sound teeth (healthy group) without any preparation were also examined. The first group presented odontoblastic processes in intimate contact with the extracellular matrix, while the collagen fibers appeared more aggregated and organized than those of the second group. These results were also observed in the healthy teeth. The results suggest that laser irradiation accelerates the recovery of the structures at the dentine-pulp interface involved during cavity preparation layer.

    Palavras-Chave: teeth; dentin; oral cavity; lasers; radiation effects

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  • IPEN-DOC 12991

    NUNEZ, S.C. ; GOMES, L.; GARCEZ, A.S.; LAGE-MARQUES, J.L.. Comparative study between photodynamic therapy and chemical solution on bacterial reduction in root canals. Brazilian Dental Journal, v. 15, Special issue, p. 85-85, 2004.

    Abstract: One of the major medical problems facing mankind in the next century will be the resistance of many pathogenic microbes to existing antibiotics. Oral bacteria can easily reach other body sites and also spread to other individuals. Therefore, antibiotic-resistant oral bacteria have the opportunity for rapid dissemination through the community and to transfer their resistance genes to other bacterial species. Photodynamic therapy involves the use of light-activated drugs which may offer an alternative approach to the use of traditional antimicrobial agents. The purpose of this study was to evaluate bacterial reduction in infected root canal. Thirty teeth with their root canals prepared were contaminated with Enterococcus faecalis. Control group was untreated. Chemical group was treated with sodium hypochlorite for 30 minutes and in the laser group, a photosensitizer paste was placed and maintained in the root canals for 5 minutes and irradiated with a diode laser, output power 10 mW and l= 685nm for 3 minutes. The bacterial reduction was significantly higher for laser group when compared to chemical and control groups. These results indicate photodynamic therapy as an effective method to kill E. faecalis.

    Palavras-Chave: photodynamic therapy; oral cavity; teeth; antimicrobial agents; microbial drug resistance

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  • IPEN-DOC 12376

    NUNEZ, S.C. ; GOMES, L.; GARCEZ, A.S.; MULLER, K.P. ; JORGE, A.O.C.; RIBEIRO, M.S. . Photodynamic action of toluidine blue in streptococcus mutans by fluorescence spectroscopy. Brazilian Dental Journal, v. 15, Special issue, p. 84-85, 2004.

    Abstract: The antimicrobial activity of toluidine blue associated with red light has been demonstrated for a wide range of microorganisms including those commonly found in infected root canals, carious lesions and periodontal pockets. Recent reports have drawn attention to the problems of antimicrobial resistance and resistance of oral bacteria to antibiotics and local antiseptics is of increasing concern, thus photodynamic therapy could be an alternative antimicrobial approach to treat localized infections in oral cavity. In this study the fluorescence spectra of TB were obtained before and after laser exposure in the presence or absence of Streptococcus mutans. The dye concentration was 0.01%, the irradiation was performed with a diode laser, l= 660 nm, P= 40mW, exposure time of 3 minutes in a volume of 0.5 ml, with a pre-irradiation time (PIT) of one or five minutes. The results showed shifts in fluorescence spectra observed for different preirradiation times in the presence of S. mutans. In the absence of bacteria, a shift in the spectra was observed in the dye before and after irradiation. These findings may indicate a photobleaching of the dye denoting structural alterations after irradiation and confirm the importance of the PIT for the success of this therapy.

    Palavras-Chave: dentistry; caries; bacteria; antimicrobial agents; toluidine blue

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  • IPEN-DOC 11770

    YAMADA JUNIOR, A.M. ; HAYEK, R.R.A.; GIOSO, M.A.; FERREIRA, J.; BATISTA SOBRINHO, C.A.; RIBEIRO, M.S. . Bacterial reduction by photodynamic therapy in peri-implantitis: an in vivo study. Brazilian Dental Journal, v. 15, Special issue, p. 84-84, 2004.

    Abstract: Progressive peri-implantar bone losses, which are accompanied by inflammatory process in the soft tissues is referred to as peri-implantitis. The aim of this study was to compare the effects of lethal photosensitization with the conventional technique on bacterial reduction in ligature induced peri-implantitis in dogs. Seventeen third premolars of eight Labrador dogs were extracted and, immediately after, the implants were submerged. After osseointegration, peri-implantitis was induced. After 4 months, ligature were removed and the same period was waited for natural induction of bacterial plaque. The dogs were randomly divided into two groups. In the conventional group, they were treated with the conventional techniques of mucoperiosteal flaps for scaling the implant surface and irrigation with chlorexidine. In the laser group, only mucoperiosteal scaling was carried out before photodynamic therapy. On the peri-implantar pocket an azulene paste was introduced and a GaAlAs low-power laser (l= 660 nm, P= 30 mW, E= 5,4 J and Dt= 3 min.) was applied. Microbiological samples were obtained before and immediately after treatment. The results of this study showed that Prevotella sp., Fusobacterium e S. Beta-haemolyticus were significantly reduced for the conventional and laser groups (100%,99.8%; 100%,100%; 85.7%,97.6%, respectively).

    Palavras-Chave: dentistry; teeth; implants; bone tissues; bacteria; photodynamic therapy; lasers; photosensitivity

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  • IPEN-DOC 11228

    KOHARA, E.K. ; CRUZ, D.R.; WETTER, N.U. ; RIBEIRO, M.S. . Effects of low-intensity laser therapy on the Orthodontic movement velocity of human teeth: a clinical study. Brazilian Dental Journal, v. 15, Special issue, p. 84-84, 2004.

    Abstract: Low-intensity laser therapy (LILT) has been studied in many fields of Dentistry, but, to our knowledge, it is the first time that its effects on orthodontic movement velocity in humans are investigated. In our study, eleven patients were recruited for a two-month study. One half of the upper arcade was considered control group and received mechanical activation of the canine teeth every thirty days. The opposite half received the same mechanical activation and was also irradiated with a diode laser (?=780nm) on ten points around the root, during 10s with 20 mW, 5 J/cm2, on four days of each month. Data of the biometrical progress of both groups were statistically compared. All patients showed significant higher retraction velocity of the canines on the laser treated side when compared to the control. Conclusion: Our findings suggest that LILT does accelerate human teeth movement and could therefore considerably shorten the whole treatment duration.

    Palavras-Chave: teeth; orthodontic treatments; semiconductor lasers; light emitting diodes; therapy; bone tissues

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  • IPEN-DOC 11177

    BARROSO, M.C.S.; WETTER, N.U. ; PELINO, J.E.P.. Dental bleaching efficacy with diode laser and LED irradiation: an in vitro study. Brazilian Dental Journal, v. 15, Special issue, p. 77-77, 2004.

    Abstract: Objective: This in vitro study evaluated the whitening efficacy of LED and diode laser irradiation during the dental bleaching procedure, using the two agents Opalescence X-tra and HP Whiteness. Background: Bleaching techniques achieved significant advances with the use of coherent or incoherent radiation sources to activate the bleaching chemicals. Methods: Atotal of 60 bovine incisors were randomly divided into six groups, three for each bleaching agent, receiving 1) only agent, 2) agent and LED irradiation at wavelength of 470 nm, 3) agent and 1.6 watt diode Laser at 808 nm. The results of the irradiations were characterized with the CIELAB system by measuring the L*a*b* values for the teeth before and after bleaching. Results: The average increase of the lightness value (CIELAB L*) of the different groups was 3-7 and the average chroma value decreased by 5-9. Conclusions: This is to our knowledge the first time that the light sources Laser and LED are compared with respect to their whitening capability when applied to different agents. Best overall results are obtained with the Whiteness HP and Laser association.

    Palavras-Chave: teeth; bleaching; enamels; semiconductor lasers; light emitting diodes

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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.

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

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

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