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  • IPEN-DOC 25946

    YOUNG, N.C.; MOSCA, R.C. ; ZEITUNI, C.A. ; ARANY, P.R.. Smart dental fillings with ruthenium nanoparticles-enhanced photobiomodulation therapy for pulp-dentin regeneration. In: SOCIETY FOR BIOMATERIALS ANNUAL MEETING AND EXPOSITION, 42nd., April 3-6, 2019, Seattle, Washington, USA. Abstract... New Jersey, USA: Society For Biomaterials, 2019.

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  • IPEN-DOC 25945

    LIMA, CASSIO ; CORREA, LUCIANA; BYRNE, HUGH; ZEZELL, DENISE M. . FTIR spectroscopy: a valuable tool to diagnose cutaneous tumors. In: NEXT FRONTIERS TO CURE CANCER, 10-12 de maio, 2018, São Paulo, SP. Abstract... São Paulo: A.C.Camargo Cancer Center, 2018.

    Abstract: Biological molecular bonds with an electric dipole moment that can change by atomic displacement due to natural vibrations are infrared active and therefore are quantitatively measured by Fourier transform Infrared Spectroscopy (FTIR), which is a rapid and label-free analytical tool that has been used to study the chemical interactions between biomolecules. The potential of FTIR spectroscopy as a diagnostic tool to discriminate cancerous from healthy tissue in a non-subjective manner has been well demonstrated. However, translation into clinical practice has been relatively slow, mainly due to the expensive and fragile infrared substrates required to perform the measurements. Thus, this study aims to demonstrate the ability of FTIR microspectroscopy to discriminate healthy skin from hyperplastic, papilloma and squamous cell carcinoma using standard H&E stained samples placed on glass slides. After approval of the ethics committee for research on animals (Comite de Etica no Uso de Animais, CEUA) of Instituto de Pesquisas Energéticas e Nucleares (IPEN) (project no. 164/15-CEUA-IPEN/SP), cutaneous neoplastic lesions were chemically-induced in the back of Swiss mice using a well- -stablished two-stage carcinogenesis protocol [1]. Healthy tissue was collected from animals non-exposed to chemicals and different diseased stages (hyperplastic epidermis, papillomatous lesions and squamous cell carcinoma (SCC)) were obtained by varying the exposure time of the animals to carcinogenenic factors.Tissue sections of 5 μm thickness were obtained from formalin-fixed paraffin-embedded (FFPE), hematoxylin & eosin stained and placed on glass slides. FTIR images were acquired in transmission mode over the spectral range 3000-3800 cm-1 with a pixel size of 6.25 × 6.25 μm at a spectral resolution of 4 cm-1. Spectral data were vector normalised and subjected to smoothing using Savitzky–Golay filtering with a polynomial of second order in an eleven point window. Principal components analysis (PCA) was applied and the PC scores were used as input data for linear discriminant analysis (PC-LDA) in a binary classification test. The groups were pairwise compared and the method was validated by leave-one-out cross-validation (LOOCV). All pre-processing and spectral analysis were performed on Matlab® R2017. Considering the sensitivity as the proportion of spectra collected from healthy tissue correctly identified in the healthy group and specificity as the proportion of spectra measured from neoplastic skin correctly associated to neoplastic group, the performance of classification obtained by PC-LDA was calculated for each pairwise comparison: Healthy × Hyperplastic, Healthy × Papilloma, Healthy × SCC, Hyperplastic × Papilloma, Hyperplastic × SCC, Papilloma × SCC. Sensitivity and specificity values over 90% were obtained for all groups compared, indicating that the information retained by bands peaking at 3000-3700 cm-1 in the infrared spectra — associated with the stretching vibrational modes of N-H, O-H and C-H chemical bonds on biological tissue — can discriminate normal and malignant tissue using H&E stained samples placed on glass slides. Thus, FTIR spectroscopy associated to PC-LDA as a binary classification test may be used as a complementary tool to help physicians to detect early stages of skin cancer, as well as to differentiate different types of cutaneous tumors.

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  • IPEN-DOC 25941

    SANTANA, L.V. ; COTRIM, M.E.B. ; SISTI, C. ; SILVA, C.M.; SAID, D.S. ; PIRES, M.A.F. . Determination of the minimum sample mass of U3Si2 to be used as candidate reference material for chemical analyses of total uranium and total silicide. In: INTERNATIONAL SYMPOSIUM ON NATURALLY OCCURRING RADIOACTIVE MATERIAL, 8th, October 18-21, 2016, Rio de Janeiro, RJ. Proceedings... Vienna, Austria: IAEA, 2018. p. 356-360. (Proceedings Series IAEA).

    Abstract: To guarantee the reliability and comparability of analytical data, the use of reference materials is essential. Uranium intermetallic compounds, in particular U3Si2, have been the preferred fuel materials for high flux research reactors. A method for the quantitative determination of the minimum representative sample mass of a candidate for reference material for determination of total uranium and silicide is described and illustrated in this paper. The analytical method used for determination of total uranium was the high precision potentiometric titration method of Davies and Gray, while total silicide was determined gravimetrically. The study was conducted according to ISO Guide 35. A preliminary test for homogeneity can be performed after homogenization as an integral part of the candidate reference material preparation.

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  • IPEN-DOC 25940

    ALMEIDA, H.C.; NASCIMENTO, T.B.S.; TADDEI, M.H.T.; MAZZILLI, B.P. . Comparison of 210Pb and 210Po activity concentrations for sediment dating. In: INTERNATIONAL SYMPOSIUM ON NATURALLY OCCURRING RADIOACTIVE MATERIAL, 8th, October 18-21, 2016, Rio de Janeiro, RJ. Proceedings... Vienna, Austria: IAEA, 2018. p. 213-217. (Proceedings Series IAEA).

    Abstract: Records stored in natural archives, such as those for lake sediments, are used in environmental programmes for the assessment of changing erosion rates in a catchment arising from disturbances, and to monitor pollution by heavy metals and other contaminants. Accurate sediment chronologies are important to interpret those practices. One of the most important methods for dating recent sediments is through 210Pb. This radionuclide occurs naturally as one of the 238U decay series. It is widely distributed on Earth owing to its decay from radium in the ground or from radon that emanates to the atmosphere. The 210Pb is deposited as particulates and falls into lakes where it is scavenged from the water column and deposited in the basins. The elevated 210Pb concentrations are measured using the gamma spectrometry technique. However, this technique has a low sensitivity and small values are difficult to detect or require a long measurement time. The determination of 210Po (a decay product of 210Pb) using alpha spectrometry is more sensitive and rapid. The aim of this paper is to compare the activity concentrations of the two radionuclides in lake sediment samples to evaluate the use of 210Po in the dating of sediments with low levels of 210Pb.

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  • IPEN-DOC 25939

    ROSA, M.M.L. ; TADDEI, M.H.T.; CARRASCO, I.C.A.; CHEBERLE, L.T.V.; AVEGLIANO, R.P. ; MAIHARA, V.A. . Radionuclides of natural origin in food and water from a high background radiation area in south-eastern Brazil. In: INTERNATIONAL SYMPOSIUM ON NATURALLY OCCURRING RADIOACTIVE MATERIAL, 8th, October 18-21, 2016, Rio de Janeiro, RJ. Proceedings... Vienna, Austria: IAEA, 2018. p. 165-168. (Proceedings Series IAEA).

    Abstract: Food consumption is one of the main entry routes of radionuclides into the human body. Concentrations of radionuclides of natural origin vary according to several factors such as local geology, climate and agricultural practices. High background radiation areas have attracted much interest from a radiation protection point of view. The Poços de Caldas Plateau is located in south-eastern Brazil and is regarded as a high background radiation area. The situation of the resident population in the region of Poços de Caldas is of special interest for public health surveillance. The activity concentrations of radionuclides of natural origin in 19 groups of food and drinking water were determined. These radionuclides were quantified using gamma spectrometry, ultra low level alpha and beta total counting, and alpha spectrometry, after group preparation and/or radiochemical separations. The results of this study showed that the food groups analysed give rise to a low effective ingestion dose. Calculations were performed using the total radionuclide concentration in each food group, the mass consumed per day by each population group, the total time considered, and the dose intake of each radionuclide. The average annual effective dose received by members of the urban population on the Poços de Caldas plateau was 0.555 mSv.

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  • IPEN-DOC 25938

    PECEQUILO, B.R.S. ; CAVALCANTE, F. ; BARROS, L.F. ; FERREIRA, A.O. ; FONSECA, L.M. ; MATEUS, C. . Self-attenuation factors in gamma-ray spectrometry of samples containing radionuclides of natural origin. In: INTERNATIONAL SYMPOSIUM ON NATURALLY OCCURRING RADIOACTIVE MATERIAL, 8th, October 18-21, 2016, Rio de Janeiro, RJ. Proceedings... Vienna, Austria: IAEA, 2018. p. 461-465. (Proceedings Series IAEA).

    Abstract: High resolution gamma-ray spectrometry is currently the most widely used analytical technique for qualitative and quantitative determination of radionuclides. Quantification of elements relies on the correct analysis of the spectra, depending strongly on the efficiency calibration of the measurement apparatus, most often performed with aqueous standard multi-radionuclide solutions. For efficiency calibration curves obtained by this method and for samples containing radionuclides of natural origin such as sand, soil, rocks and wall paint with apparent typical densities higher than that of water, self-attenuation correction factors were experimentally determined for hundreds of different samples using the Cutshall transmission technique. The results show that, to obtain more reliable analyses, correction factors for the self-attenuation behaviour, especially in the lower part of the energy spectrum, should be used. Since attenuation depends not only on the density of the sample but also on its chemical composition, correction factors have to be determined for each sample.

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  • IPEN-DOC 25937

    FONSECA, L.M. . Concentrations of 226Ra, 232Th and 40K in Brazilian wall paint. In: INTERNATIONAL SYMPOSIUM ON NATURALLY OCCURRING RADIOACTIVE MATERIAL, 8th, October 18-21, 2016, Rio de Janeiro, RJ. Proceedings... Vienna, Austria: IAEA, 2018. p. 204-207. (Proceedings Series IAEA).

    Abstract: Geological materials used as building materials are a source of radiation exposure due to the presence of radionuclides of natural origin. Wall paint is one of the building materials to be considered for radiological evaluation as it generally contains titanium dioxide pigment obtained from minerals such as ilmenite and rutile which contain 238U and 232Th series radionuclides and 40K. In this work, radionuclide concentrations were determined in 50 commercial Brazilian white latex wall paints using high resolution gamma-ray spectrometry. The following activity concentrations were measured: 1.41–38.7 Bq/kg (226Ra), 0.9–101.2 Bq/kg (232Th) and 5.9–256 Bq/kg (40K). These results demonstrate that the wall paints studied in this work are safe for use.

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  • IPEN-DOC 25936

    SILVA, A.R. ; DAMATTO, S.R. ; LEONARDO, L. ; GONÇALVES, P.N. ; SOUZA, J.M. ; MADUAR, M.F. . Radionuclides of natural origin in environmental samples collected in the catchment area of Ponte Nova reservoir, São Paulo, Brazil. In: INTERNATIONAL SYMPOSIUM ON NATURALLY OCCURRING RADIOACTIVE MATERIAL, 8th, October 18-21, 2016, Rio de Janeiro, RJ. Proceedings... Vienna, Austria: IAEA, 2018. p. 179-185. (Proceedings Series IAEA).

    Abstract: Natural radiation is generally classified as terrestrial primordial radiation or cosmogenic radiation. Primordial radiation is mostly due to the decay series of 238U and 232Th and is present in soil, sediments and water; another important source of natural radiation is 40K. Reservoirs are a very dynamic system with several phenomena to study, due to their huge impact on ecosystems and river flow. Ponte Nova reservoir (23°34'43.23"S, 45°56'56.76"W) is the first reservoir in a cascade system that was built in the 1970s to control the Upper Tietê River basin water flow. In the present work, the activity concentrations of 238U, 226Ra, 210Pb, 232Th, 228Th, 228Ra and 40K were determined using instrumental neutron activation analysis and gamma spectrometry in soil profiles collected in the catchment area of Ponte Nova Reservoir and sediment cores collected close to the soil samples. The highest concentration obtained in the soil samples was for 40K that varied from 49 to 2410 Bq/kg and 210Pb in the sediment samples, which varied from 20 to 774 Bq/kg. Cluster analysis and principal component analysis were applied to all the results obtained to verify a probable correlation between the radionuclides determined in the soil and sediment samples.

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  • IPEN-DOC 25935

    MOREIRA, E.G. ; VASCONCELLOS, M.B.A. ; ROSA, M.M.L.; TADDEI, M.H.T.. Radionuclides of natural origin in a Brazilian mussel reference material. In: INTERNATIONAL SYMPOSIUM ON NATURALLY OCCURRING RADIOACTIVE MATERIAL, 8th, October 18-21, 2016, Rio de Janeiro, RJ. Proceedings... Vienna, Austria: IAEA, 2018. p. 169-172. (Proceedings Series IAEA).

    Abstract: Certified reference materials are important tools for the quality assurance of analytical results. However there are several constraints for their widespread use in developing countries such as lack of technological development or difficult access to imported goods. Another issue is that analyte level differences between imported certified reference materials and local laboratory samples may be a concern in the measurement process. This contribution presents the activity concentrations of 234U, 235U, 238U and 232Th determined by alpha spectrometry after a radiochemical separation procedure and 40K and 210Pb determined by gamma-ray spectrometry in a Perna perna mussel reference material produced in Brazil. The activity concentrations obtained were included as information values in the certification process of the reference material.

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  • IPEN-DOC 25927

    NASCIMENTO, S.F.; RIBEIRO, C.; FERREIRA, T.S. ; GUEDES-SILVA, C.C. . Reatividade in vitro de nitreto de silício contendo SiO2 e SrO. In: CONGRESSO BRASILEIRO DE ENGENHARIA E CIÊNCIA DOS MATERIAIS, 23., 04-08 de novembro, 2018, Foz do Iguaçu, PR. Resumo... 2018. p. 4-4.

    Abstract: Nesse trabalho, biocompósitos densos de nitreto de silício foram estudados visando sua utilização como componentes e dispositivos protéticos que requeiram boa interação com o tecido ósseo. Para tanto, cerâmicas de nitreto de silício em diferentes composições contendo SiO2 e SrO foram obtidas. Os aditivos foram selecionados para contribuir com a bioatividade e habilidade do material final em se ligar com o osso. Além disso, a liberação de estrôncio no paciente promove a proliferação de osteoblastos, aumentando o potencial do material para aplicações biomédicas. Dessa forma, o presente trabalho tem como objetivo avaliar o comportamento biológico in vitro de cerâmicas de nitreto de silício contendo SiO2 e SrO, por meio de testes de imersão em SBF (simulated body fluid). Os resultados mostraram que as composições estudadas conduziram à formação de depósitos contendo fósforo e cálcio superficial após 4 dias de imersão, demonstrando a capacidade dos materiais para aplicações na cirurgia maxilofacial, sistemas de miniosteofixação, espaçadores na fusão intervertebral e raízes dentais.

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  • IPEN-DOC 25926

    FERREIRA, T.S. ; CARVALHO, F.M.S.; GUEDES-SILVA, C.C. . Avaliação das propriedades mecânicas e da resistência à oxidação de compósitos cerâmicos Si3N4-TiN. In: CONGRESSO BRASILEIRO DE ENGENHARIA E CIÊNCIA DOS MATERIAIS, 23., 04-08 de novembro, 2018, Foz do Iguaçu, PR. Resumo... 2018. p. 1254-1254.

    Abstract: Embora cerâmicas à base de Si3N4 já sejam utilizadas em diversas aplicações estruturais, vários compósitos de nitreto de silício têm sido estudados com o intuito de melhorar ainda mais suas propriedades mecânicas, principalmente a tenacidade à fratura. O presente trabalho visa avaliar as propriedades mecânicas e a resistência à oxidação de compósitos de Si3N4/TiN (até 30% em peso de TiN), contendo Al2O3 e Y2O3 (5% em peso de cada) como aditivos de sinterização. Amostras obtidas por prensagem uniaxial e isostática, sinterizadas a baixa pressão de nitrogênio a 1750ºC / 1 hora e 1815ºC / 1 hora, foram caracterizadas quanto à dureza e à tenacidade à fratura pelo método da impressão Vickers. O comportamento de oxidação foi avaliado por meio de tratamentos térmicos ao ar a 1400ºC por até 64 horas. Os resultados obtidos mostraram que as amostras atingiram valores de dureza entre 12,5 e 13,1 GPa, enquanto a tenacidade à fratura variou entre 6,3 e 9,3 MPa.m1/2, aumentando juntamente com a proporção de TiN no compósito cerâmico e superando os valores apresentados pelo nitreto de silício. Os testes de resistência à oxidação apresentaram valores de ganho de massa por área entre 0,7 e 6,4 mg/cm2, crescentes em função do teor de TiN presente no compósito e do tempo de exposição ao ar a 1400ºC.

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  • IPEN-DOC 25924

    FILGUEIRA, D.A.; GARDA, G.M.; PUGLIESI, R. ; PEREIRA, M.A.S. ; SAYEG, I.J.. Caracterização da mineralização epigenética de cobre na região de Nova Prata do Iguaçu, Estado do Paraná, por microscopia eletrônica de varredura e tomografia de nêutrons. In: PALERMO, NELY (Ed.); ARAUJO JUNIOR, HERMINIO I. de (Ed.); MACHADO, FABIO B. (Ed.); CORVAL, ARTUR (Ed.); VALENTE, SERGIO de C. (Ed.); DAL'BÓ, PATRICK F. (Ed.) CONGRESSO BRASILEIRO DE GEOLOGIA, 49.; SIMPÓSIO DO CRETÁCEO DO BRASIL, 9.; SIMPÓSIO DE VULCANISMO E AMBIENTES ASSOCIADOS, 7., 20-24 de agosto, 2018, Rio de Janeiro, RJ. Resumo... São Paulo: Sociedade Brasileira de Geologia, 2018. p. 1706-1706.

    Abstract: Dentre os fatores que contribuem para a mineralização epigenética destacam-se a porosidade e a permeabilidade da rocha hospedeira da mineralização. Os fluidos mineralizantes transportam elementos que, dependendo das condições físico-químicas do meio, precipitam-se, podendo vir a formar depósitos minerais. Em Nova Prata do Iguaçu afloram níveis de rocha basáltica mineralizados em cobre, que se apresenta na forma nativa, como óxidos (tenorita, cuprita), como carbonato (malaquita) e silicato (crisocola). A presença de amígdalas, vesículas e geodos na rocha basáltica confere à mesma tanto a permeabilidade necessária para a percolação dos fluidos mineralizantes, como os espaços (vazios) para a precipitação de minerais de minério e minerais secundários associados ou não aos fluidos mineralizantes. Por espectroscopia de energia dispersiva de raios X acoplada à microscopia eletrônica de varredura (EDS/MEV) foram analisados minerais de minério e minerais secundários (analcima, variedades de quartzo, feldspato), dando-se atenção especial à crisocola, cuja variação de cores está relacionada às concentrações de cobre, alumínio e ferro nesse mineralóide. Assim, a crisocola laranja apresenta concentrações de cobre entre 30 e 36% e de alumínio + ferro de até 6%, ao passo que a crisocola azul apresenta concentrações de cobre entre 40 e 41,5% (e não contém alumínio ou ferro). Quanto aos carbonatos e óxidos de cobre, as concentrações de cobre nesses minerais variam entre 62-53% e 74-81%, respectivamente. A técnica da tomografia com nêutrons foi utilizada para investigar a distribuição dos minerais de cobre em amostras de basalto vesicular, empregando-se o equipamento do IPEN-CNEN/SP que está instalado no Reator Nuclear de Pesquisas IEA-R1. Além de não destrutiva, a técnica possibilitou a visualização das estruturas internas do basalto (vesículas preenchidas ou vazias) e a estimativa da proporção em volume de vazios, de cobre nativo e de crisocola. Foram tomografados três amostras de minério e as porcentagens obtidas para os vazios foram 26%, 29% e 31% e a de minerais de cobre 1,1%, 1,7% e 2,4%, respectivamente. O método também se mostrou eficiente no imageamento de cobre nativo. Apesar de não discriminar os silicatos e carbonatos secundários que também preenchem as vesículas do basalto, estes puderam ser identificados por microscopia óptica, difração de raios X e EDS/MEV nos laboratórios do IGc-USP. Assim, o uso da tomografia de nêutrons, associados a técnicas analíticas, como o EDS/MEV, em amostras provenientes de perfis de alteração hidrotermal/intempérico de sequências basálticas contribui para caracterização não só das estruturas da rocha, mas também dos níveis mineralizados e não mineralizados e no entendimento do processo mineralizante.

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  • IPEN-DOC 25923

    LEAL, L.G.M. ; ZAMBONI, C.B. ; FROTA, L.O.O.; SIMON, M.S.L.; NASCINTO, R.M.. Caracterização multielementar do pólen da abelha Scaptotrigonaaff postica utlizando técnica de fluorescência de raios X. In: CONGRESSO BRASILEIRO DE APICULTURA, 22.; CONGRESSO BRASILEIRO DE MELIPONICULTURA, 7., 16-19 de maio, 2018, Joinville, SC. Resumo... 2018. p. 30-30.

    Abstract: Nos últimos anos a procura por produtos naturais e saudáveis cresceu significativamente e produtos oriundos da Meliponicultura (criação de abelhas sem ferrão), passaram a ser consumidos em maior escala no Brasil. Especificamente, o pólen tem ganhado destaque no âmbito nutricionalpor ser uma fonte proteica(16 a 40 %, contendo vários aminoácidos) e rica em carboidratos, lipídeos, oligoelementos minerais, fibras, hormônios e vitaminas. O pólen tem sido considerado um superalimento, mas investigação cientificas ainda são escassas, especialmente no que concerne estudos de suas propriedades especificas.O objetivo desta investigação foi avaliar o teor dos elementos inorgânicos (realização de análise multielemntar) em pólen de abelhas Scaptotrigonaaff. postica, proveniente da região de Barra do Corda, no estado do Maranhão. As analises foram realizadas utilizando espectrômetro de Fluorescência de Raios X (X-123SDD, Amptek) equipado com tubo de Raio de X de Prata e detector de Silício (Si Drift 25 mm2 x 500μm) com janela de Berílio de 0.5mil. Na análise multielementar Ca, Cl, Fe e K correspondem aos componentes majoritários enquanto P, S e Zn estão presentes como elementos traços. As concentrações obtidas encontram-se dentro dos limites máximos recomendados na legislação nacional. Essas estimativas compõem as primeiras avaliações de oligoelementos minerais deste produto natural e fornecem subsídio a apicultores à respeito de suas caraterística especificas além de contribuir com dados a relevantes no âmbito nutricional.

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  • IPEN-DOC 25922

    GUEDES, ANDERSON G.; LANDULFO, EDUARDO ; HOELZEMANN, JUDITH; LOPES, FABIO J.S. ; SILVA, MARCOS P.A.; SANTOS, RENATA S.S.; GUERRERO-RASCADO, JUAN L.; ALADOS-ARBOLEDAS, LUCAS; DUARTE, EDICLE S.F.. Evaluation of the transport of atmospheric Sahara dust on Natal-RN through the LIDAR technique of depolarization. In: INTERNATIONAL WORKSHOP ON SAND/DUSTSTORMS AND ASSOCIATED DUSTFALL, 9th, May 22-24, 2018, Tenerife, Spain. Abstract... 2018. p. 249-249.

    Abstract: The objective of this work is describe some results of the Natal LIDAR system (DUSTER), an integrating station of The Latin America Lidar Network (LALINET), aimed to detect and evaluate the transcontinental transport of Sahara dust (SD) to the Brazilian territory during the aerosol MOnitoring campaign Long-­‐range Transportation OVer Natal I (MOLOTOV I) which occurred from December 2016 to February 2017. The city of Natal is located in northeastern Brazil and is one of the continental points closest to the African continent, a important fact to observe the entry of SD in the South American continent. The DUSTER system allows the detection of signals at wavelengths of 355 nm, 532 nm (parallel), 532 nm (perpendicular) and 1064 nm. To detect and characterize SD aerosols and other particles in the atmosphere, DUSTER uses the ability of suspended aerosol particles to change the polarization state of light. The data retrieved by DUSTER allow calculate fundamental parameters in the characterization of atmospheric aerosols such as linear volume depolarization ratio (𝛿!) and particle linear depolarization ratio (𝛿!). Campaign data showed that on a few days the value of 𝛿! varied between 0.09 and 0.33 at a transport altitude within the range of 1-­‐3.3 km above sea level indicating in some cases probably a mixture of SD with other types of aerosols such as marine particles, anthropogenic pollution or biomass burning smoke. The data obtained with DUSTER have allowed verify the seasonality of this transport, the altitudes of detected particles and study its optical properties.

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  • IPEN-DOC 25921

    MAZIERO, J.S. ; CAVALCANTE, A.K. ; MARTINI, G.A. ; DAMASCENO, K.C. ; ORMENIO, M.B. ; CAVALCANTE, B.K. ; ROGERO, S.O. ; ROGERO, J.R. ; LUGAO, A.B. . In vitro and in vivo toxicity evaluation of silver nanoparticles stabilized with gum arabic. In: WORKSHOP ON ENVIRONMENTAL NANOTECHNOLOGY, 3rd, October 5-8, 2018, Sorocaba, SP. Abstract... 2018. p. 49-49.

    Abstract: Due to its properties such as size, varied shape, high surface area and high bactericidal properties, silver nanoparticles (AgNP) have been widely used in several sectors of the industry: bandages; inside food coolers, to retard spoilage; in antimicrobial insoles, to prevent odors; in air purifiers; in surgical instruments and etc [1] [2]. Considering the range of applications a great concern in the academic field, mainly ecotoxicological, as the potential impacts and risks that AgNP can cause to the environment and human health has increased. During the synthesis of AgNP it is necessary to use stabilizing agents such as gum arabic (GA), which is an exudate of dried gum, edible, from the stems and branches of Acacia senegal and A. seyal, rich in soluble fiber not viscous. GA has broad industrial use as stabilizer, thickening agent and emulsifier [3]. Based on these considerations, this work aimed to verify and compare the toxicity level of two GA-stabilized AgNP samples (Sample 1: AgNP at 147 ppm concentration, approximately 25 nm in size; and Sample 2: AgNP at concentration of 174 ppm with approximate size of 75 nm) using in vitro and in vivo assays. The in vitro cytotoxicity test was performed according to ISO 10993-5 by the neutral red uptake method in cells of the NCTC-L929 line, to obtain the IC50 (cytotoxicity index, which is the concentration of the substance causing it 50% mortality of exposed cells); and the in vivo acute ecotoxicity assay, according to the Brazilian standard ABNT NBR 12713, using Daphnia similis as the test organism to obtain EC50 (effective concentration that causes immobility in 50% of exposed organisms). The results obtained for Sample 1 were IC50 of 2.57 mg L-1 and EC50 of 4.40 μg L-1; and Sample 2: IC50 of 2.61 mg L-1 and EC50 of 6.55 μg L-1. These results demonstrated that aquatic organisms are much more sensitive to AgNP than cells in culture, raising the importance of conducting further studies related to the adversities that these nanoparticles can cause to the environment and human health. In addition, it is necessary to verify the disposal of the same in the environment, since in Brazil there are still no legislation that quantifies the permissible limits for this disposal.

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  • IPEN-DOC 25920

    GIMILIANI, G.T. . An overview of nanoplastics present in the environment: a new group of nanomaterials?. In: WORKSHOP ON ENVIRONMENTAL NANOTECHNOLOGY, 3rd, October 5-8, 2018, Sorocaba, SP. Abstract... 2018. p. 47-47.

    Abstract: Plastic pollution is an internationally recognized problem and an understanding of the behavior of plastic particles in the environment is still under development [1]. In the environment, plastics degrade into microplastics, i.e. fragments and fibers, then fragmented to nanoplastics (NPs) eventually. These microplastic particles range between 1 mm to 5 mm [2], while the definition of NPs is still under debate; different studies have set the upper size limit from 1 nm to 1 mm [3]. Daily discharges of microplastics are estimated in the range of 50,000 up to 15 million particles, whereas no information on NPs discharges is available yet [4]. The present overview highlights the importance of NPs as a contributor to environmental pollution, which are considered emerging pollutants nowadays. NPs are homo- and/or heteroaggregates conformed with colloidal behavior [3]. The presence of these particles has been evidenced in the atmosphere [5], soil and marine environment, that represents an ultimate sink for contamination [6]. According to the International Standard Organization (ISO), a manufactured nanomaterial is intentionally produced for commercial purposes to have specific properties or specific composition, therefore, the NPs cannot be considered as such [3]. Moreover, release and impact on the environment of these particles is still not evident. Though several studies with engineered plastic nanomaterials showed toxicity and sub-lethal effects with consequences not only at organism and population level but on the overall ecosystem [6], are not representatives results [8]. However, current difficulties in sampling, identifying and characterizating nano-sized debris make it hard to assess their occurrence in the environment. Thus, NPs is a recent issue in the scientific community and deserves further attention to establish new remediation technologies.

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  • IPEN-DOC 25919

    GIMILIANI, G.T. ; REDÍGOLO, M.M. ; FORNARI, M.; PARRA, D.F. ; LUGAO, A.B. ; ABESSA, D.M.S.; COTRIM, M.E.B. ; PIRES, M.A.F. . Micro- and nanoplastics in the sediments of the Santos Estuarine System, Brazil. In: WORKSHOP ON ENVIRONMENTAL NANOTECHNOLOGY, 3rd, October 5-8, 2018, Sorocaba, SP. Abstract... 2018. p. 46-46.

    Abstract: Small-scale plastic debris, such as microplastics and nanoplastics has become leading contributors to the pollution of marine and freshwater ecosystems [1]. These particles are derived from plastic degradation and produced intentionally for manufacturing products [2]. Microplastics are fragments and fibers smaller than 5 mm [3], while the definition of nanoplastics is still under debate; different studies have set the upper size limit at either 1000 nm or 100 nm [2]. The changes in the density of floating plastic debris caused by weathering process, biofilm formation and biofouling may result in sedimentation of these particles [3]. The present study investigates the presence of the micro- and nanoplastics in marine and estuarine sediments because these environments are suggested to be long-term sinks for microplastics. This study is the first investigative analysis about the presence of the micro- and nanoplastics on sediments of the Santos Estuarine System (SES), central coast of the São Paulo State, southeastern Brazil. Sediment samples from four sites distributed along in the Bugres River (23º56’49’’S – 46º22’57’’W), a small estuarine inlet located within the SES, were collected using a Van Veen grab sampler. In laboratory, the samples were then sieved with different mesh sizes (including < 63 μm), dried and evaluated for type of polymer by infrared spectroscopy (IR) and quantification of microplastics by visual sorting. IR analyses indicated that polyethylene and polypropylene were the main types of polymers found in fragments. Abundance of microplastics were likely inversely related to the mesh size of the sieve. Thus, the amount of microplastics increases as the size fractions decreases. Values ranged from 19 to 4,700 particles g-1 of sediment for 2 mm, 450 to 1,900.00 particles g-1 for 1 mm, 634 to 7,440 particles g-1 for 500 μm, 447 to 26,520 particles g-1 for 250 μm. The concentration of fibers ranged from 1.24 to 14.75 times higher compared to the concentration of fragments. In addition, the abundance of microplastics for 125, 63 and < 63 μm will be analyzed by thermogravimetric technique. Considering that the largest abundances of microplastics were found in the smallest meshes, it is expected the presence of nanoplastics in the sediment samples. The results of this study revealed relatively high concentrations of microplastics in sediments of the SES, confirming the widespread occurrence of microplastics in the Bugres River.

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  • IPEN-DOC 25918

    JACOVONE, R.M.S. ; SOARES, J.J.S. ; SOUSA, T.S. ; RODRIGUES, D.F.; SILVA, F.R.O. ; GARCIA, R.H.L. ; VICENTE, E.J.; SAKATA, S.K. . Antibacterial activity of graphene oxide/silver nanocomposite synthesized by sustainable process. In: WORKSHOP ON ENVIRONMENTAL NANOTECHNOLOGY, 3rd, October 5-8, 2018, Sorocaba, SP. Abstract... 2018. p. 85-85.

    Abstract: Graphene oxide/silver nanocomposite has excellent antimicrobial properties [1]. The traditional methods of incorporation of metal in graphene oxide usually require toxic reagents or with long periods of reaction and in high temperature [2]. The objective of this study is to develop an innovative and sustainable method of incorporating silver into graphene oxide by electron beam. This methodology does not involve toxic reagents or residues and it is carried out in a short reaction time at room temperature. Dispersed graphene oxide was mixed with silver in the complex form in water- isopropanol solution. The mix was submitted to a dose of radiation varying between 150 and 400 KGy. The nanocomposite GO/Ag characterization was performed by thermogravimetry analysis (TGA), X-ray diffraction (XDR), scanning transmission electron microscope coupled to the energy dispersive X-ray spectrometry (TEM/EDS). The antibacterial activity of GO/Ag was observed against Gram negative, Escherichia coli by plate count method. The viable cells of GO and GO-Ag was determined by plating the inoculum after 4h of exposure to different concentrations of the nanomaterials (10, 50, 100, 200 and 500 μg/mL). The results showed that for 500 μg/mL of GO, inactivation cells were ca of 5,4 %, while for GOAg, the concentration to inactivate all cell were 5 times lower (100 μg/mL). The silver nanoparticles size range from 20 to 50 nm. This work showed that GO/Ag nanocomposites that were widely studied by their antibacterial properties can be produce by ionizing radiation. This is a sustainable method that does not require toxic reagents and does not generate hazardous wastes. The short reaction time of some minutes and the ambient temperature also make the process attractive.

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  • IPEN-DOC 25916

    CAVALCANTE, A.K. ; BATISTA, J.G.S. ; MAZIERO, J.S. ; DAMASCENO, K.C. ; ORMENIO, M.B. ; CAVALCANTE, B.K. ; ROGERO, S.O. ; ROGERO, J.R. ; LUGAO, A.B. . Evaluation of the toxicity of gold nanoparticles produced by green nanotechnology in Zebrafish (Danio rerio). In: WORKSHOP ON ENVIRONMENTAL NANOTECHNOLOGY, 3rd, October 5-8, 2018, Sorocaba, SP. Abstract... 2018. p. 28-28.

    Abstract: Gold nanoparticles (AuNPs) of different sizes and shapes have been extensively studied by researchers and laboratories around the world. Several studies have demonstrated the applicability of gold nanoparticles in the treatment and diagnosis of cancer, in the treatment of chronic inflammation, infections, degenerative diseases and autoimmune diseases [1]. The synthesis of AuNPs generally involves reducing agents which present problems related to toxicity. In order to address this issue, metabolites present in various plant extracts have been exploited for the preparation of different nanoparticles. The methods that use phytochemicals to reduce metal ions provide a green approach to nanotechnology, known as green nanotechnology [2]. Researchers have shown that some phytochemicals, such as mangiferin (MGF) and epigallocatechin-gallate (EGCG), in addition to reducing and stabilizing the gold nanoparticles, are able to functionalize them. These molecules have chemical groups that allow binding to overexpressed receptors on some types of tumor cells [3]. The objective of this study was to evaluate the level of toxicity of the gold nanoparticles, reduced and stabilized with epigallocatechin-gallate (EGCG-AuNPs) in Zebrafish embryos (Danio rerio), as an indication of a possible environmental effect. To assess the developmental impact of embryos, organisms were exposed to different dilutions of the EGCG-AuNPs suspension for a 96-hour period according to OECD Protocol 236 (Fish Embryo Acute Toxicity Test-FET). Zebrafish is an established vertebrate model for the study of development, disease and is being increasingly used for both pre-clinical studies and toxicological applications due to a range of favorable traits [4]. EGCG-AuNPs demonstrated toxicity, with organ lethality being less than 33% at all concentrations used. The work provided a contribution on the toxicity of AuNPs synthesized and stabilized with the epigallocatechin-gallate reducing agent and using Zebrafish embryos as an animal.

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  • IPEN-DOC 25909

    ZAMBONI, C.B. ; SOUZA, G.O. ; ALVARENGA, A.M.; GIOVANNI, D.N.S. ; AZEVEDO, M.R.; KONSTANTYNER, T.. Detection of ions by XRF for use in the neonatal clinic. In: BRAZILIAN MEETING ON NUCLEAR PHYSICS, 41th, September 2-6, 2018, Maresias, SP. Abstract... São Paulo: Sociedade Brasileira de Física, 2018. p. 1-1.

    Abstract: In this investigation we intend to introduce bene¯ts to clinical practice in children, especially newborns and premature infants using an alternative procedure based on X-ray °uorescence technology (XRF). The establish- ment of alternative method, focusing on the use of small amounts of blood (a drop) for ions dosage, contributes with actions to humanize health care with minimal su®ering in the sense of adding another alternative for labo- ratory analysis in the pediatric practice. The dimension of this problem can be evaluated when a 3 kg newborn is considered to have between 280 mL and 300 mL of blood, while a preterm of 1 kg is in the range of 180 - 200 mL. As a result, blood collections for laboratory and functional tests in pediatric practice are the main causes of transfusions in infants, especially premature babies, depending on the dysfunction or treatment the child may need two to three collections per day. Based on these facts, the objective of this work is to analyze blood of newborns, concomitant with the traditional collection ("foot test"). The Ca, Cl, Fe and K dosage in blood samples of were determined using XRF technique. The blood samples came from the nursery of the Hospital of Itapecirica da Serra (S~ao Paulo city, Brazil). The X-Ray Fluorescence analysis was performed using X-Ray Spectrometer (X-123 SDD model - Amptek). The XRF analytical technique showed to be appropriate o®ering a new contribution to the neonatal clinic with actions to humanize health care, guaranteeing diagnostic accuracy with minimal su®ering and exposure to risks in the pediatric practice.

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  • IPEN-DOC 25908

    SILVA, PAULO S.C. da ; ZAHN, GUILHERME S. ; CARVALHO, RICARDO N. de ; GENEZINI, FREDERICO A. . Gamma ray spectroscopy studies on low and intermediate level radioactive waste from Angra-1 nuclear power plant. In: BRAZILIAN MEETING ON NUCLEAR PHYSICS, 41th, September 2-6, 2018, Maresias, SP. Abstract... São Paulo: Sociedade Brasileira de Física, 2018. p. 1-1.

    Abstract: The determination of the radionuclide composition of low - and intermediate - level radioactive waste is of paramount importance for the design and implementation of Brazil`s planned radioactive waste repository. While there is some knowledge of the radionuclides expected to be present, the exact activity values in each of the waste bins are not determined with su±cient precision, so theres an ongoing e®ort to analyze the composition of this waste and make the radioactive inventory of the bins containt, which comprises several institutions and laboratories. In the present work the gamma - ray spectroscopy of samples of resin, ¯lters and evaporator concentrate from Angra 1 nuclear power plant have been studied. Small aliquots (» 500 mg) of the distinct samples were stored in glass vials and gamma- counted in a characterized high resolution germanium detector. In order to determine the best counting time, these aliquots were counted for 24h (real - time), with the spectroscopy results saved after each full hour of counting. The resulting twenty four spectra were then analyzed with Canberras Genie - 2000 software, using ISOCS e±ciency correction tool. The results for each sample were then compared to determine the required counting time for each of the radioisotopes of interest.

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  • IPEN-DOC 25907

    LEÃO, ANICARINE R.; ZAMBONI, CIBELE B. ; SILVA, DALTON G.N. da ; MENDONÇA, RONALDO Z.; SIMONS, SIMONE M.. Alternative for the quality control of antivenom production proposed by Lonomia obliqua caterpillars using analytic techniques. In: BRAZILIAN MEETING ON NUCLEAR PHYSICS, 41th, September 2-6, 2018, Maresias, SP. Abstract... São Paulo: Sociedade Brasileira de Física, 2018. p. 1-1.

    Abstract: The caterpillars Lonomia obliqua Walker (L. obliqua) species, commonly found in southern Brazil, is very poisonous and can cause severe damage in human (haemorrhagic e®ects) after the contact that can lead to death [1]. The ¯rst case of poisoning (registered in Brazil) occurred in 1989 and the average number of accidents is closer to 500/year [2]. Nowadays, the Butantan Institute (Research Center at S~ao Paulo city, Brazil) is active in the production of this antiveneom in Latin America; it is the only producer of antilonomic serum. However, in the last two years, this caterpillar has been found in other regions due, mainly, to the expansion and destruction of natural ecosystems provide their growth in all regions of the country. To ensure that the antivenom produced (considering the di®erent origins) can be used for the manufacture of unaltered antilonomic serum, it is necessary to standardize this antidote. We intend to standardize the serum obtained from di®erent regions of origin using X-Ray Fluorescence (XRF). The experimental conditions using the compact XRF spectrometers (X-123SDD, Amptek) were optimized. The results will be compared and validated with INAA analysis.

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  • IPEN-DOC 25906

    LEAL, LUIS G.M. ; ZAMBONI, C.B. ; MENDONÇA, RONALDO Z.; SIMONS, SIMONE M.; NASCIMENTO, ROBERTO M. do. Characterization of the extract of propolis produced by Scaptotrigona aff. Postiça bee from Brazil using NAA and XRF techniques. In: BRAZILIAN MEETING ON NUCLEAR PHYSICS, 41th, September 2-6, 2018, Maresias, SP. Abstract... São Paulo: Sociedade Brasileira de Física, 2018. p. 1-1.

    Abstract: The objective of this investigation was to perform a multielemental characterization of the extract of the propolis produced by Scaptotrigona a® Posti»ca Bee (\tubi") from Barra do Corda (MA-Brasil). The extract produced by this propolis have several medical applications: it is used in the healing of wounds with an in°ammatory process, in treatment of prostate tumors and, it has activity against herpes and rubella virus [1-3]. Two analytic techniques were applied for investigation: Neutron Activation Analysis (NAA) and X Ray Fluorescence (XRF). The neutron activation measurements were performed using the IEA-R1 nuclear reactor at IPEN - CNEN/SP and XRF data were obtained using a compact X- Ray spectrometer (X-123 SDD, Amptek) constituted by a Silicon detector coupled a mini X-ray tube (Ag). Direct analysis using EDXRF was compared with INAA procedure to evaluate the e®ect matrix and the results were satisfactory. These data increase the knowledge of the components and can introduce improvements in the production these extracts, mainly as regards to toxicity and nutritional composition.

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  • IPEN-DOC 25905

    CAVALCANTI, H. de S. ; MIURA, VIVIANI M. ; ZAMBONI, CIBELE B. ; SILVA, DALTON G.N. da ; AZEVEDO, MARIA R.. The potassium reference value in blood in inhabitants of Brazil using EDXRF technique. In: BRAZILIAN MEETING ON NUCLEAR PHYSICS, 41th, September 2-6, 2018, Maresias, SP. Abstract... São Paulo: Sociedade Brasileira de Física, 2018. p. 1-1.

    Abstract: In this investigation, we intend to determine potassium levels in human blood aiming to study in more details the common de¯ciencies in Brazilian population helping their diagnostic well as to facilitate the interpretation of data deriving from clinical practice. The potassium takes part in the human being metabolism and it is very important for preservation of the osmotic and acid-base equilibria of human °uids, so its variations are generally associated to pathological processes. The objective of this study is the establishment of reliable potassium reference value in blood, using EDXRF technique, with emphasis on the statistical treatment. The samples came from Blood Banks from di®erent parts of Brazil. The biological samples were obtained from a select healthy group (male and female blood donors), following the procedure conventionally establish for blood donation. The in°uence of sex and age was evaluated considering several range for age (18-20, 21-30, 31-40, 41-50, 3 51 years). The result is presented following a descriptive statistics procedure, which includes the evaluation of mean, standard deviation, median and mode. This statistical treatment make possible the comparison with data derived for di®erent population groups. These results show small di®erences when a comparison is performed in function of age and sex emphasizing the necessity to adopt ranges.

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  • IPEN-DOC 25898

    GARCIA, VANESSA S.G. ; PEREIRA, MARIA C. ; ROSA, JORGE M. ; BORRELY, SUELI I. . Estudo sobre toxicidade do efluente e do consumo hídrico e energético no tingimento de poliamida. In: CONGRESSO NACIONAL DE MEIO AMBIENTE, 15., 25-28 de setembro, 2018, Poços de Caldas, MG. Resumo expandido... Poços de Caldas: GSC Eventos Especiais, 2018. p. 1-4.

    Abstract: O estudo concentrou-se na determinação do consumo hídrico e energético durante o tingimento da poliamida, bem como na avaliação do efeito tóxico do efluente para o microcurstáceo Daphnia similis. O processo de tingimento necessário para o tingimento de um quilograma de substrato consome energia suficiente para um banho de nove horas de duração utilizando-se um chuveiro convencional (4000 W). O efluente pode ser considerado como muito tóxico tendo em vista que a CE50 foi 0,61 ± 0,21 (%, v/v) após 48 horas de exposição. Conforme orientação da Resolução CONAMA 430/2011 o efluente deve ser tratado em nível tal que não induza toxicidade quando lançado no corpo receptor. Busca por tecnologias que permitam redução de toxicidade, reuso de efluentes e otimização de processos de tingimento, são de extrema necessidade dentro desta atividade industrial.

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  • IPEN-DOC 25896

    NISTI, M.B. ; SAUEIA, C.H.R. ; CASTILHO, B. ; MAZZILLI, B.P. . Assessment of Sr-90, Cs-137, natural radionuclides and metals in marine fish species consumed in the city of São Paulo - Brazil. In: INTERNATIONAL SYMPOSIUM ON NUCLEAR AND ENVIRONMENTAL RADIOCHEMICAL ANALYSIS, 13th, September 17-20, 2018, Cambridge, UK. Abstract... Royal Society of Chemistry, 2018. p. 68-68.

    Abstract: The study of artificial radionuclides dispersion into the environment is very important to control the nuclear waste discharges, nuclear accidents and nuclear weapons testing. The accident in Fukushima Daiichi Nuclear Power Plant on 11 March 2011, released several radionuclides in the marine environment by aerial deposition and liquid discharge, with various level of radioactivity. The 90Sr and 137Cs were two of the elements released into the environment, 90Sr is estimated that its atmospheric releases ranged from 3.3.10-3 to 0.14 PBq, and 137Cs is estimated that its atmospheric releases ranged from 7 to 20 PBq. The 90Sr and 137Cs are produced by nuclear fission with a physical half-life of 28.79 years and 30.15 years, respectively. The natural radionuclides (210Pb, 226Ra and 228Ra) were determined to check the reference values. The concentrations of metals were determined to compare with the values of the maximum limits of the regulation. The aim of this study is to quantify the concentration of the 90Sr, 137Cs, natural radionuclides and metals in the muscles of marine fish species most consumed in São Paulo city. The species and scientific names of the fishes analyzed were bluefish (pomatomus saltatrix), croaker (micropogonias furnieri), hake (merluccius merluccius), Smooth-hounds nei (Mustelus spp.), sardine (sardinella brasiliensis) and mullet (Mugil brasiliensis). The determination of 90Sr by liquid scintillation counting (LSC) measurement was performed using a 1220 Quantulus™ Ultra Low Level Liquid Scintillation Spectrometer. The 137Cs and natural radionuclides were measured by gamma spectrometry, using an HPGe detector. The metals concentration was determined by instrumental neutron activation analysis (INAA). The results obtained in this study can be used to ensure the quality of the fish consumed in the São Paulo city.

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  • IPEN-DOC 25895

    SAUEIA, C.H.R. ; NISTI, M.B. ; MAZZILLI, B.P. . Precision and accuracy of the methodology for the determination of Pb-210 by LSC and Po-210 by alpha spectrometry using a Sr-Spec resin. In: INTERNATIONAL SYMPOSIUM ON NUCLEAR AND ENVIRONMENTAL RADIOCHEMICAL ANALYSIS, 13th, September 17-20, 2018, Cambridge, UK. Abstract... Royal Society of Chemistry, 2018. p. 65-65.

    Abstract: Pb-210 and Po-210 were important from the radiation protection and environmental protection point of view, due to its high toxicity. It is part of the U-238 natural series, formed by decay of the Rn-222 gas; Pb-210 has a half-live of 22.3 years and emission beta particles with 16.5 keV (80.2%) and 63.0 keV (19.8%); and Po-210 has a half-live of 138.4 days and emission alpha particle with 5.3 MeV. The methodology for the Pb-210 and Po-210 determination is based on the purification and concentration of the radionuclides using a Sr-Spec resin from EICHRON and performed by Liquid Scintillation Counting (LSC) and Alpha Spectrometry, respectively. The sample solution was loaded onto the Sr resin column preconditioned in advance with 100 mL of 2M HCl. Lead and polonium were retained , Po-210 was stripped with 60 mL of 6M HNO3 and Pb was eluted with 60 mL of 6M HCl. Po was spontaneously deposited on a silver disc and counted on an alpha spectrometer for 80,000 seconds. The Pb solution was evaporated three times with 5 mL portions of 65% HNO3 and the final residue was dissolved in 10 mL of 1M HNO3. Pb was precipitated as Pb-oxalate, which was dried and weighed to calculate the chemical recovery using the gravimetric method. The precipitate was quantitatively transferred into a liquid scintillation vial and 1 mL of 1M HNO3 was added to dissolve the precipitate. The solution was mixed with 15 mL of Hisafe III scintillation solution. The final solution was counted on a 1220 Quantulus™ Ultra Low Level Liquid Scintillation Spectrometer for 24,000 seconds. In this paper, evaluates the accuracy and precision of the methodology of Pb-210 by LSC and Po-210 by alpha spectrometry using a separation technique with resin Sr-Spec was performed.

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  • IPEN-DOC 25613

    CASTRO, PEDRO A.A. de ; ZEZELL, DENISE M. ; MORAIS, MYCHEL R.P.T.; ZORN, TELMA M.T.. ATR-FTIR spectral monitoring of burn wound healing in skin by hierarchical cluster. In: ENCONTRO DE OUTONO, 41., 06-11 de maio, 2018, Foz do Iguaçu, PR. Resumo... São Paulo: Sociedade Brasileira de Física, 2018. p. 1-1.

    Abstract: Efficient biochemical characterization of burn wound healing stages can improve clinical routine to adjust the patient treatment. The Fourier Transform Infrared spectroscopy coupled with Attenuated Total Reflectance (ATR-FTIR) is an analytical technique that has potential capability to provide spectral biomarkers in biological material. This study aims to evaluate the feasibility of using ATR-FTIR to classify burned skin, to be able, in the future, to follow the regenerative process in patients. Wistar rat burn tissues were evaluated by ATRFTIR spectroscopy at 3, 7, 14, 21 days after burn and compared with the healthy group samples (H). For the acquisition of one spectrum, 150 scans were averaged with a resolution of 4 cm-1 and wavenumbers ranging from 4000 to 400 cm-1. Analysis of the spectra was performed using MatLab R2017a (MathWorks, EUA) software. The fingerprint region between 900 to 1800 cm-1 was separated and normalized by amide I band area. For smoothing purpose, spectra were submitted to Savitzky-Golay filter with a polynomial of second order in a fifteen points window. All spectra data were submitted to the hierarchical cluster using the single method and standardized Euclidean distance. The classification results demonstrated separation to non-wounded groups with an accuracy of 91,8% (H vs. 3D), 87,83% (H vs. 7D) and 97,96% (H vs. 14D). Interestingly, when the results from the healthy group were compared to the 21D group, the accuracy dissimilarity was 26%, which suggests that they are chemically similar implying that after 21 days the burned lesions are entirely recovered. These findings indicate that when an adequate multivariate method is applied, ATR-FTIR is suitable to detect the wounded and non-wounded skin as well as its healing stages. In this way, it is possible to conclude that ATR-FTIR can be an auxiliary analysis for the clinical routine for skin burn wound healing.

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  • IPEN-DOC 25612

    TEIXEIRA, LUCIA R.C. ; CARVALHO, MARIANA T.; GOMES, ANDERSON S.L.; ZEZELL, DENISE M. ; AMARAL, MARCELLO M.. Evaluation of vascular lesions on cutaneous and mucosa tissue in head and neck regions by Doppler Optical Coherence Tomography. In: ENCONTRO DE OUTONO, 41., 06-11 de maio, 2018, Foz do Iguaçu, PR. Resumo... São Paulo: Sociedade Brasileira de Física, 2018. p. 1-1.

    Abstract: Vascular lesions are one of the most common congenital and neonatal abnormalities, 60% of the cases affect the head and neck region. In most cases these lesions involute spontaneously with no consequences for the patient health, although complications caused by tissue deformities occur in 10%. The proper diagnosis of the different lesions type has impact on the proper choice of patient treatment. The Optical Coherence Tomography (OCT) technique obtains non-invasive real-time cross-section images of tissue structures with high resolution (ª 5μm), about 20 times greater than ultrasound. One of the characteristics of vascular lesions are the presence of blood vessels on the superficial layer of the skin, not present on normal tissue. Using the so-called Doppler OCT it is possible to identify the presence of blood flow and vessels on OCT images. The aim of this work was to evaluate the differences in the architecture of blood vessels in different types of lesions on cutaneous and mucosa tissue in head and neck regions by Optical Coherence Tomography and Doppler Optical Coherence Tomography. After approved by the Ethics Committee of IMIP (protocol no. 728.993), 27 patient lesions were imaged using a Doppler-OCT system (OCS1300SS; Thorlabs GmBH), at 1325 nm of central wavelength and 100 nm of bandwidth. Using the ImageJ software, the average diameter and mean depth of the blood vessels were measured. The average diameter and mean depth of the blood vessels were respectively equal to 114μm ± 92μm and 304.3μm ± 99μm on vascular malformation, 38.6μm ± 19μm and 297.8μm ± 132μm on skin hemangiomas, 45μm ± 16μm and 520.5μm ± 189.5μm on oral mucosa hemangioma (lips), 157.5μm ± 90μm and 695μm ± 136μm on lip lymphatic malformation, and 128μm ± 63μm and 689μm ± 217μm on lip vascular malformation. Using the flow information provided by Doppler OCT, it was possible to evaluate the differences on each lesion type. It was possible to obtain a diagnosis method to differentiate each vascular lesion on skin and oral mucosa, providing information for the early stage treatment of the lesions which will evolute.

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  • IPEN-DOC 25611

    DIAS, DERLY A. ; PEREIRA, DAISA L. ; GOMES, GABRIELA V. ; SUGAHARA, VANESSA M.L. ; ZAMATARO, CLAUDIA B. ; ZEZELL, DENISE M. ; MATHOR, MONICA B. . Effects of gamma irradiation on bovine bone microhardness and molecular structure. In: ENCONTRO DE OUTONO, 41., 06-11 de maio, 2018, Foz do Iguaçu, PR. Resumo... São Paulo: Sociedade Brasileira de Física, 2018. p. 1-1.

    Abstract: The skeletal systems is a complex mixed compounds, organic and inorganic, that should present a mechanical resistance to perform functions as protection of the vital organs and load distribution. Gamma radiation is an ionizing radiation that comes from radioative sources or X-ray generator and it is commonly used in health establishments such as radio diagnostic exams, radiotherapy and sterilization of allograft. The characterization of the irradiated bone tissue can be an important tool in the study of the components that are aÆected and how much each dose of ionizing radiation can alter its mechanical properties. This information will be very important in in vitro and ex vivo studies where sterilization of the bone material is necessary and may still be useful in understanding the eÆects on the bone tissue of patients undergoing short-term radiotherapy. For this, 110 samples of bovine femur diaphysis were randomized into 11 groups: G1- untreated (control); G2 to G11 were submitted to gamma irradiation (60Co Gammacel). Samples were polished before irradiation and submitted to a Knoop Microhardness Test to determine the hardness of bovine bone and Fourier transform Infrared spectroscopy (FTIR). Spectra were collected in the midinfrared range in Attenuated Total Reflectance (ATR) sampling mode associated whit PCA multivariate technique to evaluate the molecular changes in bone matrix. The microhardness analysis did not present a significant statistical diÆerence between the irradiated and control groups, showing that ionizing radiation did not aÆect the mechanical structure of the samples, on a micro scale. The results of FTIR with the PCA technique were eÆective in separating all groups, especially those irradiated with doses of 0.002 kGy, 10 kGy and 35 kGy. We conclude that ATR-FTIR spectroscopy associated with PCA is a good method to evaluate the biochemical changes promoted by ionizing radiation in bone matrix. It was observed that hardness was not altered by gamma irradiation and FTIR spectroscopy associated with PCA is a good method to analyze the changes in bone tissue submitted to ionizing radiation.

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  • IPEN-DOC 25610

    PEREIRA, DAISA L. ; GOMES, GABRIELA V. ; ZEZELL, DENISE M. ; DEL VALLE, MATHEUS; ANA, PATRICIA A.. Optical coherence tomography provides the optical attenuation coefficient of bovine dentin irradiated by Nd:YAG. In: ENCONTRO DE OUTONO, 41., 06-11 de maio, 2018, Foz do Iguaçu, PR. Resumo... São Paulo: Sociedade Brasileira de Física, 2018. p. 1-1.

    Abstract: Optical Coherence Tomography (OCT) is a non-destructive and non-invasive technique which provides transverse images of biological structures contactless with the sample, with no use of ionizing radiation to penetrate in the sample under analysis. These characteristics allow its clinical use without any side eÆects to the patient. The optical attenuation coe±cient (OAC) is obtained by OCT and is related to the characteristics of the tissues. This study aims to analyze the OAC from the OCT signal in bovine dentin to distinguish sound from demineralized dentin. For this, sixty 8mm2 blocks of bovine root dentin, were randomized into 4 groups: G1- untreated; G2- treated with acidulated phosphate fluoride (APF, [F]=1.23%, pH=3.3 to 3.9); G3- irradiated with Nd:YAG laser (1064nm, 0.6W, 10Hz- Lares Research R∞) without photoabsorber; G4- irradiated with Nd:YAG laser (1064 nm, 0.6W, 10 Hz- Lares Research R∞) using a coal paste as photoabsorber. All samples were submitted to a 3-day erosive demineralization protocol (Citric acid 1%, pH=3.6, 5 min, 2x/day) under agitation, and remineralization (artificial saliva, pH=7, 120 min) cycling. In this study, it was noticed that the values of optical attenuation coe±cient of all samples decreased after the erosive cycling. This finding indicates that the demineralization promoted by acids, such as the citric acid creates empty spaces in the structure of dentin that increases the number of interfaces and, as a consequence, increases the scattering of light and decreases the values of optical attenuation coe±cients. It is possible to conclude that the optical attenuation coe±cient, calculated from the OCT signal, is able to distinguish sound from demineralized bovine dentin. This quantitative parameter can be used for diagnosis and to monitor the evolution of mineral loss in patients in near future.

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  • IPEN-DOC 25609

    ZAMATARO, CLAUDIA B. ; PEREIRA, DAISA L. ; GOMES, GABRIELA V. ; ALVES, NATHALIA Z. ; CASTRO, PEDRO A.A. ; DIAS, DERLY A. ; ZEZELL, DENISE M. ; SCAPIN, MARCOS A. . Molecular characterization of ex-vivo natural bovine dental enamel. In: ENCONTRO DE OUTONO, 41., 06-11 de maio, 2018, Foz do Iguaçu, PR. Resumo... São Paulo: Sociedade Brasileira de Física, 2018. p. 1-1.

    Abstract: Bovine teeth are widely used to infer results on a human population. Considering this, an analysis of the mineral content of bovine enamel, focusing the hidroxiapatite (HA), was carried out to evaluate the homogeneity of the sample universe for future experiments with laser irradiation as a substitute of human teeth enamel. Twelve samples of 5 x 5 mm bovine enamel were prepared and polished plane. The mineral content was calculated through surface microhardness (SMH) and morphology by scanning electron microscopy (SEM). Main molecular components of the enamel were analysed by Energy Dispersive X-ray Spectroscopy (EDS). Surface microhardness is an indirect indicator of the mineral content of the samples, which was 258.2 (38.8) KHN. The compounds present in the samples, the values of Calcium and Phosphate oxides and the ration Ca/P were analizes. As expected Phosphorus pentoxide and Calcium oxide were the main constituent of the samples (57.4 to 59.9%). The CaO/P2O5 ratio shows a variation with linear correlation (R2 = 1). The elemental ratio (Ca/P) shows a change in the elemental content with linear correlation (R2 = 1). 30% of the samples presented Strontium oxide, 30% had Zirconium dioxide, 10% had Magnesium oxide and 40% had Silicon dioxide. All samples showed Sulfur trioxide, Iron trioxide and Chlorine. 10% did not shown Zinc oxide. 5% had Potassium oxide and Nickel oxide in its composition. The surface microhardness results, although only for the initial homogenization of the sample universe, showed a Knoop hardness number within a spectrum similar to that of natural hydroxyapatite of human origin. The EDS results show that bovine enamel hydroxyapatite present great similarity with that from human enamel hydroxyapatite from the point of view of chemical composition. These results corroborate the use of bovine hydroxyapatite in substitution of hydroxyapatite of human origin. Despite the inter-species similarity, it is possible to note that in the same species the composition of hydroxyapatite varies. In the bovine species, the feeding, the period of formation of the dental germs and the origin are more standardized and controlled than in humans. Nevertheless, it is possible to notice a variation of the components elements of bovine dental enamel, and it is necessary to restrict an interval of hardness and Ca/P values to homogenise the samples properties for use in any experiment.

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  • IPEN-DOC 25608

    LIMA, CASSIO ; CORREA, LUCIANA; BYRNE, HUGH J.; ZEZELL, DENISE . FTIR microspectroscopy discriminating skin cancer using tissue sections on glass. In: CONFERENCE SPEC, 10th, June 10-15, 2018, Glasgow, UK. Resumo expandido... Manchester, UK: The International Society for Clinical Spectroscopy, 2018. p. 113-114.

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  • IPEN-DOC 25605

    CASTRO, PEDRO ; LIMA, CASSIO ; ZORN, TELMA M.T.; ZEZELL, DENISE M. . FTIR spectroscopy: an optical method to study wound healing process. In: LATIN AMERICA OPTICS AND PHOTONICS CONFERENCE, November 12-15, 2018, Lima, Peru. Resumo expandido... Washington, DC, USA: OSA, 2018.

    Abstract: In this study, we investigated the ability of Fourier transform infrared spectroscopy to discriminate healthy tissue and thermal injury, aiming the development of an optical method to evaluate the wound healing process.

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  • IPEN-DOC 25604

    LIMA, CASSIO A. ; CORREA, LUCIANA; BYRNE, HUGH J.; ZEZELL, DENISE M. . Diagnosis of advanced skin cancer using Infrared spectral histopathology. In: LATIN AMERICA OPTICS AND PHOTONICS CONFERENCE, November 12-15, 2018, Lima, Peru. Resumo expandido... Washington, DC, USA: OSA, 2018.

    Abstract: In this study, we investigated the feasibility of Infrared Spectral Histopathology to diagnose invasive squamous cell carcinoma using hematoxylin and eosin stained tissue placed on conventional glass slides, as used in the pathologist workflow.

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  • IPEN-DOC 25603

    ZAMATARO, CLAUDIA B. ; SCAPIN, MARCOS ; KUCHAR, NIELSEN G. ; ZANINI, NATHALIA ; ZEZELL, DENISE M. . Molecular analysis of human and bovine hydroxyapatite from dental enamel and dentin submitted to gamma radiation. In: LATIN AMERICA OPTICS AND PHOTONICS CONFERENCE, November 12-15, 2018, Lima, Peru. Resumo expandido... Washington, DC, USA: OSA, 2018.

    Abstract: The important alteration of gamma irradiated hydroxyapatite in the buccal cavity depends on the biochemical alteration of the environment. The hydroxyapatite analyzed isolated showed a minimal molecular change of the crystal.

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  • IPEN-DOC 25602

    CASTRO, PEDRO A.A. de ; ZEZELL, DENISE M. . Discrimination of ionizing radiation effects on bone using Fourier Transform Infrared Spectroscopy using K-means. In: BIOPHOTONICS CONGRESS: BIOMEDICAL OPTICS, April 3-6, 2018, Hollywood, Florida, USA. Resumo expandido... Washington, DC, USA: OSA, 2018.

    Abstract: We demonstrated the feasibility of using ATR-FTIR spectroscopy associated with k-means clustering to evaluate the recognition of different doses. Our results open up new possibilities for protein monitoring relating to dose responses.

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  • IPEN-DOC 25601

    ANA, PATRICIA A.; SILVA, ELIZABETE dos S.F.; BENETTI, CAROLINA; AMARAL, MARCELO M. ; ZEZELL, DENISE M. ; GOMES, ANDERSON S.L.. The use of optical coherence tomography for the evaluation of the effects of an infrared laser on dentin demineralization. In: BIOPHOTONICS CONGRESS: BIOMEDICAL OPTICS, April 3-6, 2018, Hollywood, Florida, USA. Resumo expandido... Washington, DC, USA: OSA, 2018.

    Abstract: The effect of Er,Cr:YSGG laser on dentin demineralization was evaluated by optical coherence tomography, which was able to quantify and to evidence that this laser is a promissory alternative for preventing dentin caries.

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  • IPEN-DOC 25600

    LOPES, DANIELA S.; MOTA, CLAUDIA C.B.O.; PEREIRA, DAISA L. ; ZEZELL, DENISE M. ; GOMES, ANDERSON S.L.. A comparative study between acid-etching and Er,Cr:YSGG laser irradiation on enamel surface evaluated by OCT and SEM. In: BIOPHOTONICS CONGRESS: BIOMEDICAL OPTICS, April 3-6, 2018, Hollywood, Florida, USA. Resumo expandido... Washington, DC, USA: OSA, 2018.

    Abstract: This study aimed to evaluate the effects of Er,Cr:YSGG laser irradiation and acidetching on enamel surface, aiming to improve the bond strength between enamel and composite materials, through optical coherence tomography and scanning electron microscopy.

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  • IPEN-DOC 25599

    SAMAD, R.E. ; MALDONADO, E.P. ; COURROL, L.C.; ROSSI, W. de ; BALDOCHI, S.L. ; ZEZELL, D.M. ; VIEIRA JUNIOR, N.D. . High intensity femtosecond lasers at IPEN: tools for modification and characterization of materials. In: INTERNATIONAL CONFERENCE ON OPTICAL, OPTOELECTRONIC AND PHOTONIC MATERIALS AND APPLICATIONS, 8th, August 26-31, 2018, Maresias, SP. Abstract... 2018.

    Abstract: High intensity femtosecond (fs) lasers have become an affordable and versatile tool to modify all kinds of materials and to characterize the induced modifications. These capabilities derive from the ultrafast interaction between the electromagnetic field and matter, which distinguishes this kind of laser from all others. In the time frame of the fs pulses, the predominant interaction with the matter occurs through electron excitation, and several processes take place with increasing intensity: nonlinear excitation, ionization and recombination, which occur in a non-selective way due to the short time of interaction. The after-pulse evolution is due mainly to electrostatic interactions, involving the relaxation of the electrons energy to and between atoms. Coulomb and phase explosions, for example, are predominant for intensities in the range of TW/cm2 to PW/cm2, and they ablate all material (metals, polymers, dielectrics, etc) with a very high precision due to the small heat effect zone of these interactions. At the High Intensity Ultrashort Pulses Lasers Laboratory at IPEN we daily generate femtosecond pulses with intensities of 100 TW/cm2 and above. In this work we describe results obtained by our group using ultrashort pulses from Ti:Sapphire lasers covering the creation of color centers in crystals, glasses and polymers, the inscription of waveguides and the creation of surface structures that can range from the colorization of metals to the manufacture of microfluidic circuits, as well as the removal of burned tissue from living organisms. The pulses can also be used to study how defects pileup during the etching of a solid by superimposing pulses, and how the ablation process is affected by the incubation. At higher intensities the pulses can modify materials, and we present the controlled synthesis of nanoparticles, and the modification of graphite into diamond by the shockwaves generated during the ablation as a product of an evolving underdense plasma that generates local high temperatures and pressures. Also, the materials characterization is possible by spectroscopic measurements of the plasma elements atomic lines. Furthermore, we present results on the production of radiation on the deep ultraviolet by generation of harmonics of the laser interaction with gases, and also our recent efforts towards the acceleration of electrons by ultrashort laser pulses. Both the harmonics and electrons ultrafast beams could be used to modify and characterize materials by pump-probe, spectroscopic and diffraction measurements.

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  • IPEN-DOC 25598

    OGUSHI, SUSI T. ; PEREIRA, DAISA L. ; ROSCOE, MARINA G.; SOUSA, CAMILA M.; ZEZELL, DENISE M. . Comparação do tratamento da base de braquetes autoligados com jateamento de óxido de alumínio e irradiação a laser Er,Cr:YSGG. In: CONGRESSO BRASILEIRO DE ORTODONTIA, 21., 20-22 de setembro, 2018, São Paulo, SP. Resumo... 2018. p. 65.

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  • IPEN-DOC 25597

    AMARAL, M.M.; TEIXEIRA, L.R.C. ; GOMES, A.S.L.; ZEZELL, D.M. . Optical attenuation coefficient measurement of hemangioma vascular lesion in labial mucosa by Optical Coherence Tomography. In: CONGRESSO BRASILEIRO DE ENGENHARIA BIOMEDICA, 26., 21-25 de outubro, 2018, Búzios, RJ. Resumo expandido... Rio de Janeiro: Sociedade Brasileira de Engenharia Biomédica, 2018.

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  • IPEN-DOC 25569

    SANTIAGO, ELISABETE I. ; SPRANDEL, LEOPOLDO ; ANDREA, VINICIUS ; CUNHA, EDGAR F. ; ROBALINHO, ERIC ; LINARDI, MARCELO ; KORKISCHKO, IVAN . Estudos numéricos dos processos de distribuição de água durante ensaios de durabilidade em células a combustível do tipo PEM. In: CONGRESO E LA SOCIEDAD IBEROAMERICANA DE ELECTROQUIMICA, 23., 3-8 de junio, 2018, Cusco, Perú. Resumo... 2018.

    Abstract: As células a combustível estão entre as tecnologias mais promissoras, visto que estes dispositivos podem produzir energia elétrica com baixa emissão de poluentes e de forma muito eficiente [1]. O entendimento dos mecanismos de transporte de água em células a combustível do tipo PEM é um ponto chave para a definição de estratégias de gerenciamento de água e aumento de desempenho. Quantidade suficiente de água deve estar presente na célula para manter a condutividade protônica da membrana polimérica, no entanto, o excesso de água nas camadas porosas são as principais causas de perdas reversíveis [2]. Este estudo tem como objetivo a compreensão dos fenômenos envolvidos no transporte de água em células a combustível do tipo PEM em função das condições de operação da célula e propor condições de operação que otimizem o fluxo de água, permitindo maior durabilidade desse tipo de célula a combustível. Nesse sentido, foi realizado um estudo de modelagem e simulação numérica de uma célula a combustível unitária envolvendo os fenômenos de transporte e os processos eletroquímicos. A simulação da dinâmica da água foi realizada considerando um sistema bifásico (modelos de misturas) em diferentes condições operacionais, a saber temperatura e fluxo de gases. A análise dos resultados mostrou que a 0,6V, temperatura da célula de 75oC e vazão de H2 próximo a três vezes o valor estequiométrico, a temperatura ideal de umidificação é entre 80oC e 85oC. Temperaturas de umidificação maiores podem resultar em inundações dos canais de distribuição e camadas porosas enquanto temperaturas menores podem ocasionar a desidratação da membrana. A mesma temperatura de umidificação dos gases reagentes e da célula a combustível pode ser adotada desde que o fluxo de gases reagentes seja alto o suficiente para garantir a hidratação da membrana, neste caso, seis vezes o valor estequiométrico. Os resultados confirmam a importância do arraste eletro-osmótico no balanço de água e a importância de análises bifásicas em estudos de otimização de células a combustível. O balanço de água ideal pode ser alcançado definindo adequadamente os fluxos e temperaturas de umidificação dos gases reagentes em função do potencial de operação com auxílio de modelos numéricos.

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  • IPEN-DOC 25565

    RAMANATHAN, LALGUDI V. ; PIERETTI, EURICO F. ; CORREA, OLANDIR V. ; PILLIS, MARINA F. . Electrochemical evaluation AISI 316 stainless steel coated by Nb2O5 thin films. In: BRAZILIAN MRS MEETING, 17th, September 16-20, 2018, Natal. Abstract... 2018.

    Abstract: Great number of metallic engineering materials form passive films on their surfaces and, therefore, are prone to localized corrosion, usually characterized by the occurrence of pits [1,2]. The improvement of surface properties is a requirement for the metallic components used, for example, in petrochemical industry, in fuel cells, and in nuclear plants. The goal of this work was to investigate the influence of Nb2O5 films deposited by DC magnetron sputtering during 15, 30 and 50 minutes on the electrochemical behavior of AISI 316 stainless steel. The corrosion resistance was evaluated by monitoring the open circuit potential (OCP), electrochemical impedance spectroscopy (EIS) and linear potentiodynamic polarization (LP) on an electrolyte composed of 0.1 M H2SO4 in water at 25 °C. Electrochemical tests showed that the coated specimens presented a more capacitive behavior, and were less susceptible to corrosion than specimens without Nb2O5 coatings. The OCP for coated samples at 50 min had the most inferior values. Similar results were obtained by Pillis et al. [3] for Nb2O5 coatings at 15 min and 30 min in NaCl solution. These results suggest that the obtained films have a protective behavior and can be used to avoid the degradation of AISI 316 austenitic stainless steel in aggressive environments containing sulfur ions.

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  • IPEN-DOC 25564

    PILLIS, MARINA F. ; PIERETTI, EURICO F. ; ANTUNES, RENATO A.; SILVA JUNIOR, JOAO L. da; ARAUJO, EDVAL G. de. Desenvolvimento de superfícies auto-limpantes em ligas de alumínio. In: SIMPOSIO DE MICROSCOPIA NO CERRADO, 2., 05-08 de agosto, 2018, Goiânia, GO. Resumo... Rio de Janeiro: Sociedade Brasileira de Microscopia e Microanálise, 2018.

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  • IPEN-DOC 25562

    KORKISCHKO, IVAN ; SANTIAGO, ELISABETE I. ; CARMO, BRUNO S.; FONSECA, FABIO C. . Modeling, simulation and shape optimization of a proton exchange membrane fuel cell using computational fluid dynamics. In: WORLD HYDROGEN ENERGY CONFERENCE, 22th, 17-22 de junho, 2018, Rio de Janeiro, RJ. Abstract... 2018.

    Abstract: This paper presents the modeling, simulation and optimization of a single channel proton exchange membrane fuel cell (PEMFC) using computational fluid dynamics methods. The shape optimization of the cross section of the flow channels was employed to improve the electrical performance of the fuel cell. The minimization of the standard deviation of the current density on the longitudinal mid-plane of the membrane was the objective function of the single-objective optimization problem, the upper and lower widths of the flow channels were the control variables and a cross-section area restriction was imposed. The optimized flow-channel PEMFC presented improved electrical performance, with higher current and power densities and a more uniform current density distribution than the rectangular flow channel. It is also expected that a more uniform current distribution improves the durability and water management of the fuel cell.

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  • IPEN-DOC 25561

    SALES, T.S.N.; BURIMOVA, A. ; CARBONARI, A.W. ; BOSCH-SANTOS, B. ; PEREIRA, L.F.D. . Tuning the dielectric response of HfO 2 nanoparticles by Si-doping. In: INTERNATIONAL SYMPOSIUM ON NANOPARTICLES-NANOMATERIALS AND APPLICATIONS, 3rd, January 22-25, 2018, Caparica, Portugal. Abstract... 2018.

    Abstract: The properties of bulk materials and corresponding nanostructures may differ significantly which leads to distinct scopes of their applications. As the miniaturization continues, nanostructures show great potential in microelectronics. Among others, nanostructured hafnium (IV) oxide (hafnia, HfO 2 ) has attracted considerable attention due to its chemical stability and physical characteristics 1 . It has high dielectric constant ( ∼ 25) and is relatively thermally stable (melting point at 3085 K) 2 . These qualities have made hafnia an alternative to SiO 2 for gate oxide layers in field-effect transistors, since the leakage current issue and consequent thickness limitations of silica were hindering miniaturization. Clearly, the features of HfO 2 can be further tuned by doping 3 . Understanding the relation between the macro-properties of such complex systems and their architecture at atomic scale should help select doping parameters adequate for particular applications. In this work 0at%, 5at% and 10at% Si-doped HfO 2 nanoparticles (NPs) were synthesized via sol-gel method. Basic characterization included scanning/transmission electron microscopy, electron backscattering and X-ray diffraction. NPs were demonstrated to have spherical shape, sizes in the range of 10─40nm and monoclinic structure (m-HfO 2 ). Local structure and electronic environment of the samples was probed with perturbed angular correlation (PAC) spectroscopy. Sample irradiation resulted in the formation of 181 Hf isotopes (PAC probes 4 ) at several sites whose decay to 181 Ta is preferentially through an intermediate (metastable) state with lifetime depending strongly on local extra-nuclear fields. Thus, time distribution of decay probability provided information on the ambient of the probe. For undoped sample PAC data has revealed two distinct Hf sites, one of those possessing well-defined quadrupole frequency ν Q ≈ 750 MHz and electric field distribution asymmetry η ≈ 0.36. Site occupation raised with temperature from 16% at T = 473K to 75% at T = 1073K, which agrees with the results found in the literature for the quadrupole interactions of 181 Ta in m-HfO 2 4 . For the doped samples (both Si 5at% and 10at%) additional site was observed. Symmetrical electric field distribution ( η = 0) and a greater site fraction at T = 673─873K allowed to attribute it to a tetragonal phase of hafnia. First principles analysis has shown that doping m-HfO 2 with certain cations can induce the formation of tetragonal phase 5 . We emphasize that this phase is desirable for transistor applications since it is associated with the highest dielectric constant.

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  • IPEN-DOC 25558

    LEAL, G.M.L.; ZAMBONI, C.B. ; GIOVANNI, D.N.S.; NASCINTO, R.M.; MENDONCA, R.Z.; SIMONS, M.S.. Elemental caracterization of the extract of propolis produced by Scaptotrigona Aff postica bee from Brazil using EDXRF and INAA techniques. In: EUROPEAN CONFERENCE ON X-RAY SPECTROMETRY, June 24-29, 2018, Ljubljana, Slovenia. Abstract... 2018.

    Abstract: The Scaptotrigona Aff Postica bee is an insect stingless belonging to Apidae family and subfamily Meliponinae. This genus occurs throughout in Neotropics. In Brazil, it is found in the northeastern mainly in the Barra do Corda County (Maranhão). Specifically, the extract of propolis produced by this bee have several medical applications. It is used in the healing of wounds with an inflammatory process and in treatment of prostate tumors as well as food supplement [1-3]. Considering its importance in medicinal use and the great variability in relation to botanical origin, its standardization in relation to the dosage of ions and metal is important to meet the different medical applications. The objective of this investigation was to perform a multielemental characterization using Energy Dispersive X-Ray Fluorescence (EDXRF) and Instrumental Neutron Activation Analysis (INAA) techniques. The neutron activation measurement was performed in the nuclear reactor (IEA-R1, 3-4 MW, at IPEN) and XRF data were obtained using a mini - X Ray spectrometer with Ag and Au targets. These data increase the knowledge of its inorganic components and can introduce improvements in the production these the extracts, mainly as regards to toxicity. Moreover, considering that the demand for natural products has increase (Brazil stands out as world exporter of honey and derivatives), these data also contributes for checking the quality and food safety.

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  • IPEN-DOC 25557

    ZAMBONI, C.B. ; GIOVANNI, D.N.S. ; SALVADOR, V.L.R. ; SATO, I.M. ; MENDONCA, R.Z.; WEN, F.H.; SIMONS, M.S.. Multielemental analyses of lonomia obliqua (Lepidoptera, Saturniidae) caterpillar using XRF and NAA techniques. In: EUROPEAN CONFERENCE ON X-RAY SPECTROMETRY, June 24-29, 2018, Ljubljana, Slovenia. Abstract... 2018.

    Abstract: The elemental composition of the Lonomia obliqua caterpillar Walker, 1855 (Lepidoptera, Saturniidae) was investigated using X-Ray Fluorescence (XRF) and Neutron Activation Analyses (NAA) techniques. The need of this study is related to morphological changes (mainly size and color) observed in some caterpillars used for preparation of antiveneom (antilonomic serum). This species is poisonous and has the ability to cause serious and fatal hemorrhagic effects in humans after contact characterized by hemorrhage, disseminated intravascular coagulation, and acute renal failure [1, 2]. The first case of poisoning (registered in Brazil) occurred in 1989 and the average number of accidents is closer to 500 / year [3]. To reverse these effects, a specific antivenom (antilonomic serum) is currently produced by Instituto Butantan (Research Center at São Paulo city). For this investigation, the samples were classified as healthy (caterpillars of control) and unhealthy (caterpillars visibly modified). The XRF measurements were performed in an EDXRF Spectrometer SHIMADZU Co. model Rany 720 and the NAA measurements in the IEA-R1 nuclear reactor (both facilities of IPEN, Research Center at São Paulo city). The results show significant differences (high concentration) for several elements in unhealthy caterpillars that can affect the development of this specie as well as the quality and yield of the antiveneom. Furthermore, the elemental characterization of this species can also contribute for the understanding the potential pharmacological (pro-coagulant and anti-thrombotic) in the prevention of life-threatening blood-clots.

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  • IPEN-DOC 25556

    GONÇALVES, G.M. ; LIMA, G.N.S. ; MACEDO, M.V. ; ORTIZ, N. . Water removal of oxytetracycline using titanium dioxide/solar photodecomposition and biocarbon adsorption. In: BIOCHAR, August 20-23, 2018, Wilmington, Delaware, USA. Abstract... 2018.

    Abstract: Oxytetracycline (OTC) is a broad-spectrum antibiotic with efficacy against infections, high solubility in water and used both in veterinary and human medicine, primarily in poultry and livestock, but also for human consumption. Nowadays Brazil is the higher protein producer in the world, and the agribusiness is the strongest economy sector in the country. The OTC use is increasing in veterinary medicine and also its detection in surface water resources and sewage treatment effluents. The conventional water treatment processes have to improve to enhance the pharmaceuticals removal efficiency. The occurrence of OTC in the natural environment can affect the selection of genetic variants of resistant microorganisms, inducing a risk to the ecosystem and human health. The experiments started with the dilution of standard oxytetracycline solution. They solutions were preheating before the addition of TiO2 and kept in a solar radiation chamber during 120 minutes. The addition of micronized biocarbon (diameter < 500 mesh) in all collected suspension aliquots followed by shaking, and centrifugation at 1500 rpm for 15 minutes allows the supernatants OCT measurements at UV – Visible Spectrophotometer Cary 13 at λ = 268 nm and 373 nm. The absorbance values were converted to antibiotics concentration using an analytical curve prepared with standard antibiotics solutions. After the processes optimization, the OCT removal percentage reached 95%with pseudo-second-order kinetics and better isotherm agreement with Langmuir R2= 0.689 and Redlich-Peterson with R2 = 0.738.

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  • IPEN-DOC 25555

    SOARES JUNIOR, FRANCISCO H.; VIEIRA, LAIS H. e S.; OTUBO, LARISSA ; SOARES, JOAO M.; FERREIRA, ODAIR P.. Magnetic hydrochar prepared from sugarcane bagasse. In: BRAZILIAN MEETING ON INORGANIC CHEMISTRY, 19th; LATIN AMERICAN MEETING ON BIOLOGICAL INORGANIC CHEMISTRY, 6th; BRAZILIAN MEETING ON RARE EARTHS, 8th, September 24-28, 2018, Fortaleza, CE. Abstract... 2018.

    Abstract: Magnetic hydrochar is known for its technological applications such as environmental remediation, biosensors, adsorption, drug delivery and catalysis [1]. However, magnetic iron oxide can be easily oxidized, causing reduction of magnetic properties. Because of these limitations, such materials could be improved for greater stability. Hydrothermal carbonization at moderate temperatures (150-350°C) has been recognized as a auspicious and efficient methodology for preparing carbonaceous material from biomass residues [2, 3]. In this work, we performed the preparation and characterization of magnetic hydrochar via one-pot hydrothermal carbonization of biomass. The samples were prepared by treating hydrothermally sugarcane bagasse in presence of iron nitrate (III). Reaction parameters such as temperature, time and mass proportion of iron nitrate to bagasse were studied. Structural characterization revealed a mixture of iron oxide phases: hematite and maghemite. SEM and TEM images showed spherical particles with mean diameter between 1-5 μm and irregular clusters of nanostructures with diameters ranging from 5-11 nm, respectively. On the surface were detected oxygen groups (hidroxila, fenólica, carbonila ou carboxílica). The specific surface area was measured to be 71.54-162.63 m2/g and it’s saturation magnetization 13.1-34.3 emu/g. The results suggest that the samples were composed of carbon microparticles and iron oxide nanoparticles. The carbon layers were observed to be encapsulating the iron oxide nanoparticles, in which the magnetite phase is responsible for the magnetic response.

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  • IPEN-DOC 25553

    PIERETTI, EURICO F. ; ANTUNES, RENATO A.; NEVES, MAURICIO D.M. das . Tribological evaluation of an optical fiber laser marked stainless steel for biomedical applications. In: CONGRESSO BRASILEIRO DE ENGENHARIA BIOMEDICA, 26., 21-25 de outubro, 2018, Búzios, RJ. Poster... Rio de Janeiro: Sociedade Brasileira de Engenharia Biomédica, 2018.

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  • IPEN-DOC 25544

    PIERETTI, EURICO F. ; ANTUNES, RENATO A.; NEVES, MAURICIO D.M. das . Avaliação do efeito do tratamento superficial a laser na resistência à degradação de um biomaterial. In: CONGRESSO BRASILEIRO DE ENGENHARIA BIOMEDICA, 26., 21-25 de outubro, 2018, Búzios, RJ. Poster... Rio de Janeiro: Sociedade Brasileira de Engenharia Biomédica, 2018.

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  • IPEN-DOC 25549

    MARTINS, P.A. ; SOUSA, J.A.; ESTRELA, I.M.O.; SILVA, N.G. ; FUKUMORI, N.T.O. ; MATSUDA, M.M.N. . Adequação do ensaio de distribuição biológica de TIN-TEC à farmacopeia europeia. In: CONGRESSO BRASILEIRO DE MEDICINA NUCLEAR, 32., 10-12 de agosto, 2018, São Paulo, SP. Resumo... São Paulo: Sociedade Brasileira de Medicina Nuclear, 2018.

    Abstract: Introdução – O ensaio de biodistribuição em animais de experimentação está especificado em monografias de alguns reagentes liofilizados (RL) marcados com tecnécio-99m nas farmacopeias e em guias da Agência Internacional de Energia Atômica (AIEA) para garantir a eficácia e a qualidade do produto. Uma vez que esse ensaio esteja descrito para um determinado radiofármaco, é mister que o fabricante o execute. O estanho coloidal (99m Tc) (TIN-TEC) é empregado em linfocintilografia, cintilografia gástrica e imagem do sistema retículoendotelial. Objetivo – Este trabalho avaliou a biodistribuição do TIN-TEC em camundongos, para adequação à farmacopeia europeia, em relação ao ensaio realizado no IPEN, o qual se baseava no guia da AIEA com a utilização de ratos da linhagem Wistar. Material e Métodos – Foram analisados 6 lotes de TIN-TEC em ratos Wistar (150-250 g) e camundongos Swiss (20-25 g). O ensaio foi realizado em 3 animais de cada linhagem, para cada lote. O RL foi marcado com 370 MBq (10 mCi) em 3 mL de solução de Na99mTcO4. Após 30 minutos de reação, administrou-se na veia caudal de cada um dos animais, uma dose de 7400 – 11100 MBq (200 – 300 μCi) em 0,2 mL. Após 20 minutos de biodistribuição, os animais foram eutanasiados com dose letal de anestésico e a radioatividade do fígado, baço, pulmão e carcaça (sem a cauda) foi medida em calibrador de doses (Ci), e o cálculo de % dose retida (% D.R.) em cada um dos órgãos foi efetuado. Resultados – Os Limites de Especificação descritos para estanho coloidal (99m Tc) na Farmacopeia Europeia 9.0 são: % D.R. Fígado+baço ≥ 80% e % D.R. Pulmão ≤ 5%. Todos os resultados de % D.R. nos órgãos de estudo encontraram-se de acordo com os limites em ambas as linhagens de animais. A % D.R. de Fígado+Baço situou-se entre 84,44 – 92,90 e 91,83 – 98,29, para camundongos e ratos, respectivamente, enquanto os resultados de % D.R. no pulmão foram similares e a % D.R. carcaça apresentou-se maior em camundongos. Discussão – A realização do ensaio de biodistribuição com resultados em conformidade com os requisitos descritos em compêndios oficiais assegura a distribuição fisiológica apropriada do radiofármaco no órgão alvo em humanos. Os resultados obtidos para o TIN-TEC em camundongos dentro dos limites de aceitação da monografia da farmacopeia europeia permitiram estabelecer a adequação aos critérios farmacopeicos. Conclusões – As diferentes linhagens de animais no ensaio de biodistribuição do TIN-TEC confirmaram a eficácia e a qualidade do produto.

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  • IPEN-DOC 25548

    SILVA, N.G. ; MATOS, M.C.C.V. ; SILVA, R.A. ; FUKUMORI, N.T.O. ; MATSUDA, M.M.N. . Avaliação de sistemas cromatográficos para controle de qualidade de mertiatida (99m Tc). In: CONGRESSO BRASILEIRO DE MEDICINA NUCLEAR, 32., 10-12 de agosto, 2018, São Paulo, SP. Resumo... São Paulo: Sociedade Brasileira de Medicina Nuclear, 2018.

    Abstract: Introdução – A determinação da pureza radioquímica (% PRq) de mertiatida (99m Tc) tem sido objeto de estudos devido à complexidade na separação das impurezas. Um dos ensaios descritos nas farmacopeias americana e europeia é o controle radioquímico para a determinação de tecnécio hidrolisado por cromatografia em papel (CP), com fase móvel de acetonitrila e água (60:40) (v/v). Chen et al. desenvolveram sistemas cromatográficos para 99mTcO2 e 99mTcO4- por CP e CCD (cromatografia em camada delgada). Objetivo – Este trabalho avaliou o efeito da fase móvel e da fase estacionária na determinação da % PRq da mertiatida (99m Tc) de formulação IPEN. Material e Métodos – A radiomarcação foi realizada em frascos de reagente liofilizado (RL) de MAG3 (mertiatida) reconstituídos com eluato de 99mTcO4- obtido de gerador de 99Mo/99mTc (IPEN-CNEN/SP). Foram utilizados misturas de solventes acetato de etila, metiletilcetona, acetonitrila e água purificada e suportes cromatográficos de ITLC-SG, TLC-SG e papel Whatman 3 (W3), Whatman 1 (W1) de 12,5 centímetros de comprimento e 1,5 de largura. A % PRq foi determinada pelo cálculo das % de impurezas e os resultados foram expressos como média ± desvio padrão (DP), até 4 horas de marcação (240 minutos), em triplicata de dois frascos (N=6). Apόs a separação cromatográfica, as tiras de papel ou CCD foram secas, cortadas em segmentos de 1 cm e a radioatividade foi medida (cpm) em contador gama Perkin Elmer. Resultados – A formulação do RL de MAG3 desenvolvida no IPEN foi analisada utilizando os sistemas cromatográficos propostos por Chen et al., a saber, acetato de etila e metiletilcetona (2:3) (v/v) e acetonitrila e água (50:50) (v/v) com ITLC-SG e W3, para determinação de 99mTcO4- e 99mTcO2, respectivamente. Metiletilcetona pura não evidenciou melhoria na separação das espécies e acetato de etila pura não possibilitou a separação de 99mTcO4-. A mistura de acetonitrila e água (50:50) (v/v) representou melhor fase móvel para determinação de 99mTcO2 . Discussão – O método de CCD e CP proposto por Chen et al. mostrou-se eficiente na determinação das principais impurezas de mertiatida (99m Tc) obtendo-se valores acima de 90% de % PRq, atendendo às especificações das farmacopeias para a mertiatida (99m Tc), preparada com a formulação desenvolvida no IPEN-CNEN/SP. Conclusões – O sistema cromatográfico utilizado para o controle radioquímico durante a fase de desenvolvimento da formulação IPEN apresentou melhor resolução permitindo a determinação das impurezas radioquímicas de mertiatida (99m Tc).

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  • IPEN-DOC 25531

    ASFORA, VIVIANE K.; ANTONIO, PATRICIA L. ; GONÇALVES, JOSEMARY A.C. ; BARROS, VINICIUS S.M. de; BUENO, CARMEN C. ; KHOURY, HELEN J.; CALDAS, LINDA V.E. . TL and OSL response of CaF2:Tm for electron beam radiation processing. In: INTERNATIONAL SYMPOSIUM ON RADIATION PHYSICS, 14th, October 7-11, 2018, Córdoba, Argentina. Abstract... 2018.

    Abstract: The use of electron beams for industrial applications has increased worldwide requiring accurate dosimetry systems to assure the quality of irradiated products. The radiochromic films and alanine/EPR dosimeters are often employed in electron beam radiation processing. The thermoluminescent (TL) and optically stimulated luminescent (OSL) dosimeters are mainly used for the electron beam dosimetry for radiotherapy applications. The aim of this work is to study the TL and infrared stimulated luminescence (IRSL) response of the calcium fluoride dosimeter doped with thulium (CaF2:Tm) for electron beam radiation processing. The pellets of CaF2:Tm (6mm in diameter and 1mm thickness) were produced via the solution combustion synthesis technique at the Nuclear Energy Department - UFPE. The individual TL and OSL sensitivities of a bach of these dosimeters were previously evaluated and 50 pellets with a standard deviation of 6% were selected to be used in this study. Irradiation was performed at the Radiation Technology Center at IPEN-CNEN/SP using 1.5MeV electron beam from a DC 1500/25/4 – JOB 188 accelerator covering the dose rate range 2-32kGy/s and doses from 0.5kGy up to 10kGy. The TL and OSL readings were carried out after a preheating at 100°C during 15min using a Riso TL/OSL reader, model DA-20. The TL measurements were taken with a heating rate of 2°C/s, in the range from 50°C to 350°C. The OSL readings were carried out with infrared stimulation with optical power attenuated to 20% during 240s. Residual thermoluminescent glow curves for IRSL were recorded after stimulation times. The reproducibility and stability of the TL and IRSL responses were also evaluated, as well as the dependence with different dose rates from 2kGy/s up to 32kGy/s. The results showed a deconvoluted TL glow curve with four components, being the main two TL peaks centred in the regions of 150°C and 200°C. The area of the TL peaks increases linearly with the absorbed dose up to 6kGy for all the dose rates evaluated. For doses higher than 6kGy, the TL response is sublinear with saturation around 10kGy. The IRSL curves of the dosimeters present a fast and a slow decaying IRSL signals. The total area of IRSL curves were measured for both different doses and dose rates. The correspondent results were linearly dependent on the absorbed dose and saturated in almost 10kGy. The IRSL residual TL glow curves exhibited a symmetrical decrease to the growing OSL signal. All the results presented regarding TL and IRSL response of CaF2:Tm have shown that these dosimeters are suitable for electron beam dosimetry in radiation processing.

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  • IPEN-DOC 25530

    GONÇALVES, JOSEMARY A.C. ; MANGIAROTTI, ALESSIO; BUENO, CARMEN C. . Current response stability of a commercial PIN photodiode for low dose radiation processing applications. In: INTERNATIONAL SYMPOSIUM ON RADIATION PHYSICS, 14th, October 7-11, 2018, Córdoba, Argentina. Abstract... 2018.

    Abstract: The increasing interest in low-dose (<100 Gy) radiation processing applications, as irradiation of blood for transplants and substerelization of insects, has demanded efforts to develop reliable dosimetry systems with high sensitivity, good spatial resolution and stable response over the range of 5-100 Gy. Silicon diodes fulfil these requirements and their uses in diodebased dosimeters are deemed appropriate with the advantage of providing prompt dose-rate and dose results. However, due to the low radiation tolerance of such dosimeters, they are rarely employed in radiation processing, where absorbed doses of tens of kGy can be easily achieved in regular applications. Experimentally, the low radiation hardness of ordinary silicon diodes operating in current mode manifests itself in a rapid drop of their current sensitivities with increasing accumulated doses. This effect is physically attributed to the decrease of the diffusion length of minority charge carriers, due to traps and defects induced by radiation in the silicon bulk, leading to the decrease of sensitive volume of the diode. Consequently, it is expected that thin diodes (with negligible thickness compared with the minority carrier diffusion lengths) are almost insensitive to variations of diffusion lengths and hence more resistant to radiation damage effects. From this assumption, a semiconductor dosimeter system was developed based on a commercial thin photodiode (type SFH206K) in a p-layer/intrinsic/n-layer (PIN) structure operating in short-circuit current mode. In this work, the response of this diode as a dose-rate meter has been investigated with respect the linearity between dose-rate and current, particularly addressing the stability of the current sensitivity with the absorbed dose. The dose was gathered off-line by the integration of the current signal during the exposure time. Irradiations were performed in both 60Co facilities of Panoramic and Gamma Cell types, covering the dose-rate range 8-660 Gy/h. The current-response of the diode proved to be linearly dependent on the dose-rate characterized by a current sensitivity of 0.2 nA.h/Gy. The stability of the current delivered by the diode for each dose-rate was evaluated as a function of the absorbed dose in several steps from 100 Gy to 15 kGy. In all measurements, current intensities were stable during the exposure time and proportional to the dose-rates with sensitivities variation less than 5% (k=2). In an attempt to lend further theoretical support to these results, calculations of the current generated in the sensitive volume of the diode were performed taking into account its dimensions, dose-rates and the values of diffusion lengths available in the literature. Good agreement between theoretical and experimental results was achieved.

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  • IPEN-DOC 25529

    GARCIA, VANESSA S.G. ; ROSA, JORGE M. ; PEREIRA, MARIA da C.C. ; BOIANI, NATHALIA F. ; BORRELY, SUELI I. . Avaliação da toxicidade do umectante não iônico e do corante reativo RED 239 submetidos à irradiação por feixe de elétrons. In: CONGRESSO BRASILEIRO DE ECOTOXICOLOGIA, 15., 01-04 de setembro, 2018, Aracaju, SE. Resumo expandido... 2018.

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  • IPEN-DOC 25526

    BOIANI, NATHALIA F. ; GARCIA, VANESSA S.G. ; TOMINAGA, FLAVIO K. ; BORRELY, SUELI I. . Toxicidade do Propranolol (comercial versus manipulado), e de sua mistura com o cloridrato de fluoxetina, quando tratado por radiação ionizante. In: CONGRESSO BRASILEIRO DE ECOTOXICOLOGIA, 15., 01-04 de setembro, 2018, Aracaju, SE. Resumo expandido... 2018.

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  • IPEN-DOC 25521

    WETTER, NIKLAUS U. ; GIEHL, JULIA M. ; JIMENEZ-VILLAR, ERNESTO ; ANACLETO, DANILO . Polydispersed powders (Nd3+:YVO4) for ultra efficient random lasers. In: BRAZILIAN MRS MEETING, 17th, September 16-20, 2018, Natal. Abstract... 2018.

    Abstract: Random lasers hold the potential for cheap, coherent light sources that can be miniaturized and molded into any shape with several other added benefits such as speckle-free imaging and cancer detectin, however, they require improvements specifically in terms of efficiency. This talk details for the first time a strategy for increasing the efficiency of a random laser that consists in using smaller particles, trapped between large particles to serve as absorption and gain centers whereas the large particles control mainly the light diffusion into the sample. In order to to determine the samples’ transport mean free path, fill fractions, laser efficiency and the average photon path lengths inside the scattering medium for backscattered pump photons, measurements of backscattering cone, sample absorption, reflection and laser emission are done. A record slope efficiency of 50% is reached by optimizing pump photon diffusion and absorption in a powder pellet composed by a polydispersed particle size distribution (smaller particles between bigger ones) from a grinded and sieved 1.33 mol% Nd:YVO4 crystal with mean particle size of 54 micrometers.

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  • IPEN-DOC 25519

    WETTER, N. ; JIMENEZ-VILLAR, E. . Random Laser materials: from ultrahigh efficiency to Anderson localization transition. In: INTERNATIONAL CONFERENCE ON OPTICAL, OPTOELECTRONIC AND PHOTONIC MATERIALS AND APPLICATIONS, 8th, August 26-31, 2018, Maresias, SP. Abstract... 2018.

    Abstract: Random Lasers hold the premise for cheap coherent light sources that can be miniaturized and molded into any shape and used for speckle-free imaging in biology, remote sensing, display technology, encrypting, cancer detection and distributed amplification [1]. However, they require improvements specifically in terms of efficiency. This work details for the first time a strategy for increasing the efficiency of a random lasers that consists in using smaller particles, trapped between large particles to serve as absorption and gain centers whereas the large particles control mainly the light diffusion into the sample. A record slope efficiency of 50% was achieved using yttrium vanadate particles of mean particle size of 54 m by optimizing the distribution of the polydispersed particles. The random lasers have been completely characterized by measurements of backscattering cone, absorption and reflection measurement, etc. in order to determine transport mean free path, lT, average photon path length and fill fractions. A similar strategy, this time using a colloidal suspension of core-shell nanoparticles (TiO2@Silica) in ethanol solution of Rhodamine 6G, allowed us to observe the transition regime to Anderson localization [2]. Narrow peaks with similar amplitude overlapped to a super-fluorescence band are observed in the emission spectrum. These narrow peaks show complete suppression of interaction amongst them. The strategy used in these samples relies on the fact that the interaction between scatterers (separation < size) leads to an inhomogeneous distribution of scatterer positions at the microscopic scale, leading to micrometric regions with klT values lower than the averaged klT value determined experimentally and possibly with klT ~1 (Ioffe-Regel criterion).

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  • IPEN-DOC 25518

    WETTER, NIKLAUS U. ; JIMENEZ-VILLAR, ERNESTO . Ultra-high efficiency and low threshold in random lasers. In: LATIN AMERICA OPTICS AND PHOTONICS CONFERENCE, November 12-15, 2018, Lima, Peru. Resumo expandido... Washington, DC, USA: OSA, 2018.

    Abstract: Random lasers hold the potential for cheap and coherent light sources, however, improvements in terms of efficiency and laser threshold are required. In this paper, we show two new strategies to increase efficiency and decrease the laser threshold.

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  • IPEN-DOC 25514

    LIMA, G.N.S. ; MORAIS, G.; MACEDO, M.V.; AYOUB, J.M.S. ; ORTIZ, N. . Biocarbon adsorption and TiO2/solar photodecomposition of binary and tertiary antibiotics systems. In: BIOCHAR, August 20-23, 2018, Wilmington, Delaware, USA. Abstract... 2018.

    Abstract: The occurrence of pharmaceutical residues in a polluted environment includes the exposition to a contaminant mixture including antibiotics rather than individual toxic compounds. Some published results confirm the detection of a variety of antibiotics in soil and water environment as binary and tertiary systems which highlight the importance of antibiotics removal study of from a binary and tertiary mixture. Experimentaly the antibiotic mixture was preheating before adding TiO2 and kept in a solar radiation chamber with constant temperature and pH values. The collection of the suspension aliquots allows the photodecomposition control followed by the addition of micronized biocarbon (diameter < 500 mesh) agitation and centrifugation. The supernatants measurements used spectrophotometer UV-Vis at λ = 273nm, 261nm, and 373nm to amoxicillin, cephalexin, and oxytetracycline, respectively. All results indicate the TiO2/solar photodecomposition followed by biocarbon adsorption have better agreement with pseudo-second-order kinetics. The comparison between the antibiotics photodecomposition removal percentages of the binary mixtures indicates higher decomposition for amoxicillin (57,38%), followed by cephalexin (48,04%) and considering the tertiary antibiotic systems the oxytetracycline (14,63 %). Such removal difference is a result of the antibiotics chemical structure and bounding energy broken by the hydroxy radicals of the solar/TiO2 photodecomposition reaction. For amoxicillin, the results refer to break the weak thiophene sulfur bond, for the cephalexin and oxytetracycline they have to break the strong hydrogen bonding of amide (amino carbonyls group) and the benzamide bond.The use of the biocarbon adsorption in the water treatment is final stage ensure the water quality polishing results.

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  • IPEN-DOC 25513

    GUILHEN, S.N. ; ORTIZ, N. ; IZIDORO, J.C. ; FUNGARO, D.A. . Activation of biochar obtained from slow pyrolysis of the macauba coconut residue for removing uranium from aqueous solutions. In: BIOCHAR, August 20-23, 2018, Wilmington, Delaware, USA. Abstract... 2018.

    Abstract: Macauba (Acrocomiaaculeata) is a palm tree native to the savannah-like area of Central Brazil. As a result of the oil extraction from its coconuts, a dark stiff residue, the “endocarp”, rich in lignin content, has a potential for being exploited as feedstock for biochar production. This study investigates the activation of biochar obtained from slow pyrolysis of the macauba coconut residue in order to remove uranium from aqueous solutions. The non-activated biochar, referred to as “BC350”, is produced at a pyrolytic temperature of 350°C under Ar atmosphere and a 1- hour residence time. The activated biochar was produced the same way and was further subjected to activation via physical route using CO2 at 850°C for 120 min. The product of this treatment was named “BC350-A”. Both biochars were characterized by specific surface area. The surface area increased from 0.832 (untreated biochar) to 643.12 m2 g-1, confirming the improvement of the porosity. The removal efficiency for uranyl ions (U(VI)) increased from 80.5 (untreated biochar) to 99.2% for 5 mg L-1 initial concentration solution adjusted to pH 3 using a 10 g L-1dosage. Adsorption isotherms were employed to represent the results of the U adsorption onto the BC350-A. An estimation of the best fit was performed by calculating different deviation equations, also called error functions. The Redlich-Peterson isotherm model was the most appropriate for fitting the experimental data. This hybrid model incorporates both Langmuir and Freundlich’s isotherm functionalities. These results demonstrate that a valueadded material can be produced, encouraging the exploration of thermochemical conversion of lignocellulosic biomasses.

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  • IPEN-DOC 25512

    GOMES, A.A. ; BUSTILLOS, J.O.W.V. ; VIANNA JUNIOR, A.S.; LANDULFO, E. ; ROSSI, W. de . Development of a microfluidic circuit "microreactor" to atmospheric analyses. In: WORKSHOP LIDAR MEASUREMENTS IN LATIN AMERICA, 10th, November 19-23, 2018, Medellín, Colombia. Abstract... 2018.

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  • IPEN-DOC 25511

    BOIDI, G.; TERTULIANO, I.S.; FROFITO, F.J.; ROSSI, W. ; MACHADO, I.F.. Effect of laser surface texturing on friction behaviour of lubricated point contact under different sliding-rolling conditions. In: LEEDS-LYON SYMPOSIUM ON TRIBOLOGY, 45th, September 04-07, 2018, Leeds, UK. Abstract... 2018.

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  • IPEN-DOC 25552

    DONATO, MARESSA; ALVAREZ, CARLOS; RIBEIRO, MARTHA S. ; ITRI, ROSANGELA. Effects of Pore-forming toxins (PFTs) on oxidized model membranes represented by Giant Unilamellar Vesicles (GUVs). In: CONGRESSO DA SOCIEDADE BRASILEIRA DE BIOFISICA, 43., 27-30 de setembro, 2018, Santos, SP. Resumo... Rio de Janeiro: Sociedade Brasileira de Biofísica, 2018. p. 79-79.

    Abstract: Sticholysin I (St1) and II (St2) are polypeptides isolated from the Caribbean sea anemone Stichodactyla Helianthus, with a molecular mass of 19401 and 19290 Da, with hemolytic and pore-forming properties in membranes (LANIO et al., 2000). It has been previously determined that the activity of membrane pore formation is related to the N-terminal insertion in the bilayer and lipid phase coexistence must play a role too (ROS et al., 2013). As PFTs, both toxins are considered to have potential appliance in parasitic and tumor diseases (MARTÍNEZ et al., 2007). In this work, we have investigated GUVs composed of nonoxidized POPC and POPC hydroperoxide (POPC-OOH) interacting with ST1 and ST2 by optical microscopy. The results did not reveal a significant PFT-membrane interaction such that no membrane destabilization was observed over incubation time of 20 min. On the other hand, when GUVs were made of mixtures of POPC or POPC-OOH and Sphingomyellin (SM), optical contrast fading was noticed indicating an increase in lipid bilayer permeability due to pore formation. Of note, neither micron-sized pores were observed nor membrane disruption. Further, the results also pointed out vesicles composed of oxidized lipids and SM have a much faster pore forming capacity. Therefore, our results thus suggest that membranes containing -OOH and SM promote the insertion of toxins due to their great fluidity, facilitating the insertion of the TFPs and their differentiation, leading to the formation of pores.

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  • IPEN-DOC 25551

    PELEGRINO, M.T.; DIMMER, J.A.; SEABRA, A.B.; RIBEIRO, M.S. ; CABRAL, F.V. . Evaluation of combined photodynamic inactivation and no releasing chitosan nanoparticles on cutaneous leishmaniasis. In: CONGRESSO DA SOCIEDADE BRASILEIRA DE BIOFISICA, 43., 27-30 de setembro, 2018, Santos, SP. Resumo... Rio de Janeiro: Sociedade Brasileira de Biofísica, 2018. p. 64-64.

    Abstract: Cutaneous leishmaniasis (CL) is a chronic disease developed by parasites of the genus Leishmania that promotes destructive lesions. The available treatments are limited because of side effects, resistance and toxicity. New strategies against CL have been studied such as Photodynamic inactivation (PDI) and exogenous NO donors. The aim of this work was to explore the effects of methylene blue (MB)-mediated PDI in association with encapsulated NO donors in chitosan nanoparticles (NPNO) on Leishmania amazonensis. NPNOs were tested in vitro with L. amazonensis transgenic line expressing luciferase at increasing concentrations (25-200μM) and inhibitory concentrations (IC50 and IC90 ) were calculated. Based on inhibitory concentrations results, twelve BALB/c mice were infected in the left footpad and randomly assigned to experimental groups (n=4): Control (non-treated), G1 (two PDI sessions), G2 (two PDI sessions and 80 μM of NPNO, immediately after PDI) and G3 (only 80 μM NPNO). PDI was performed using a red LED (λ= 660±22 nm) at 150 J/cm² fluence and MB at 100 μM. Parasite burden was obtained by bioluminescence every day, in the first 96 h and for the next 4 weeks, once a week. Test groups presented significant reduction in parasite load compared to control during all experimental period. In the first 24 h after treatments, parasite burden was significant lower for G2. After 96 h, all test groups were similar. Following 4 weeks, statistically significant differences were noticed when test groups were compared to control but parasite burden was similar among all treated groups. Under conditions used in this study, our results show that NPNOs were not able to sustain the parasite killing promoted by MB-mediated PDI on CL induced in mice 24 h after treatments.

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  • IPEN-DOC 25550

    YOSHIMURA, T.M. ; BAPTISTA, M.S.; RIBEIRO, M.S. . Biochemical changes in serum of obese mice related to photoactivation of brown adipose tissue. In: CONGRESSO DA SOCIEDADE BRASILEIRA DE BIOFISICA, 43., 27-30 de setembro, 2018, Santos, SP. Resumo... Rio de Janeiro: Sociedade Brasileira de Biofísica, 2018. p. 35-35.

    Abstract: Obesity is closely related to the development of insulin resistance and type-2 diabetes. Mammal fat consists of white and brown adipose tissues (WAT and BAT). Although most fat is energy-storing WAT, brown adipocytes dissipate energy as heat. Thus, the thermogenic capacity of BAT and its activation makes it an interesting target for treating metabolic syndrome (MS). On the other hand, photobiomodulation (PBM) has proven to be beneficial to manage the chronic inflammatory component of obesity and hyperglycemia by irradiating WAT. However, PBM has still not been used to activate BAT. In this work, obese and hyperglycemic mice were treated with PBM, and their BAT was irradiated. The mouse serum was collected and submitted to attenuated total reflection (ATR)- Fourier transform infrared (FTIR) spectroscopy to evaluate the biochemical changes promoted by PBM. Five animals were fed with standard food (normal diet – ND) and used as negative control. The remaining 10 animals were submitted to a hyperlipidic diet (high fat – HF) and their body mass, Lee index and glycemia were measured weekly during 15 weeks to induce MS. After MS establishment, the HF animals were divided into two groups: HF and HF660. The HF660 group was exposed to six irradiation sessions using a 662 ± 20 nm LED. The radiant exposure was 5.7 Jcm-2 at 19 mWcm-2 per session, delivered at 300 s, on days 1, 3, 7, 10, 14 and 21. The HF group was sham-irradiated. After the treatment ended, the mouse serum was collected from cardiac puncture under deep anesthesia. Serum samples were prepared and analyzed by ATR-FTIR spectroscopy. The lipid absorptions were responsible for the clearest differences among the IR spectra. An intense C=O stretching absorption at 1742 cm-1 was noticed only for HF group. Acyl CH2 stretching absorptions at 2853 and 2925 cm−1 were also more pronounced in HF group. After PBM, these major lipid peaks decreased their vibrational modes. In fact, hierarchical cluster analysis identified the similarities between the spectra and grouped ND and HF660 groups into a same cluster. Taking together, our findings suggest that PBM applied to the BAT is able to promote biochemical changes in serum of obese mice mainly in lipid bands.

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  • IPEN-DOC 25504

    PEREIRA, SAULO ; CONTATORI, CAROLINA ; RIBEIRO, MARTHA S. . Low level light therapy on breast tumor. In vitro and in vivo studies. In: CONGRESSO DA SOCIEDADE BRASILEIRA DE BIOFISICA, 43., 27-30 de setembro, 2018, Santos, SP. Resumo... Rio de Janeiro: Sociedade Brasileira de Biofísica, 2018. p. 62-62.

    Abstract: Low Level Light Therapy (LLLT) has been gaining prominence in health areas due to search for less invasive and cost-effective treatments. However, its use is not indicated to treat patients with cancer due to a few studies in vivo. The aim of this work was to evaluate the effects of LLLT on breast tumor 4T1 cells in vitro and in a murine model. For the in vitro assay, 4T1 cells were submitted to a single session of LLLT with red light (660 ± 20 nm) delivering energies of 1.2 J and 6 J. The cell viability was measured by MTT assay. For in vivo study, nine BALB/c female mice (6 weeks old) received 4T1 cells transfected with luciferase (4T1-Luc) into the mammary fat pad. After two weeks, the animals were divided into control (n=3) and test groups were submitted to LLLT with same parameters described above. The tumor progression was monitored by a caliper and bioluminescence. The anti-fatigue effect of LLLT was assessed by a forced swimming test. Our results showed that LLLT was not able to increase cell viability regardless the energy used. In vivo, the lower energy promoted an increase of the tumor volume compared to control group. On the other hand, the higher energy was able to arrest tumor progression as well as increase the swimming time. Taken together, our results suggest that LLLT triggers opposite effects on breast tumor depending on the type of assay.

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  • IPEN-DOC 25503

    HADDAD, PAULA; SAULO, VICTOR T.; RIBEIRO, MARTHA S. ; PEREIRA, SAULO T. ; YOSHIMURA, TANIA M. . Superparamagnetic iron oxide nanoparticles covered with methylene blue for antimicrobial photodynamic therapy. In: INTERNATIONAL MATERIALS RESEARCH CONGRESS, 27th, August 19-24, 2018, Cancún, México. Abstract... 2018.

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  • IPEN-DOC 25501

    SOUZA, FELIPE M.; PARREIRA, LUANNA S.; OLIVEIRA, VITOR H.A.; PINHEIRO, VICTOR S.; BATISTA, BRUNO L.; NANDENHA, JULIO ; NETO, ALMIR O. ; SANTOS, MAURO C.. Niobium as co-electrocatalyst for Pd in alkaline medium: improved selectivity and mechanism for ethanol electrooxidation reaction. In: REUNIAO ANUAL DA SOCIEDADE BRASILEIRA DE QUIMICA: CONSTRUINDO O AMANHA, 41., 21-24 de maio, 2018, Foz do Iguaçu, PR. Resumo... São Paulo: Sociedade Brasileira de Química, 2018.

    Abstract: Direct ethanol fuel cells (DEFC) have been evaluated as a possible alternative source of sustainable energy, because it can reach high current densities with minimal pollutant production [1]. In this work, we report the synthesis of PdxNby/C binary electrocatalysts supported on Vulcan XC-72 carbon by the sol-gel method [2]. These synthesized electrocatalysts were physically characterized by DRX, EDS, ICP-MS, XPS and TEM. Their electrochemical activities (CV and CA) were evaluated as already reported by Souza [2]. Here, we reported new results from Tafel plots and FTIR ex situ experiments for ethanol oxidation reaction using those electrocatalysts. Pd/C electrocatalyst has the EOR governed by two determining steps since it showed two straight lines between 570 mV and 730mV, presenting also two different slopes (a and b, in Figure 1). Unlike the other electrocatalysts, with Nb in their chemical composition, that the EOR occurs by one determining step since there is just one slope. The exchange current densities (A cm-2) were 2.3x10-17, 2.7x10-12, 6.6x10-10, 3.6x10-11 and 7.3x10-11 for Pd/Ca, Pd/Cb, Pd1Nb1/C, Pd3Nb1/C and Pd1Nb3/C, respectively. This shows that Nb increases the electron exchange rate at the analyte/electrode interface, improving the kinetics of the EOR reaction [3]. FTIR experiments strengthened the evidence that Nb modifies the Pd mechanism for EOR electrocatalysis to a mechanism that present almost no formation of acetaldehyde, avoiding the reaction ... The FTIR spectra showed that Pd1Nb1/C displays the highest production of CO2 and the lowest production of acetaldehyde. Furthermore, the ADT experiments with ICP-MS analysis indicated that Pd1Nb1/C obtained the highest peak current density during 1000 cycles of the experiment, presenting the lowest Pd mass loss after the ADT.

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  • IPEN-DOC 25485

    GENTIL, TUANI C.; PARREIRA, LUANNA S.; SOUZA, FELIPE M. de; PINHEIRO, VICTOR S.; NANDENHA, JULIO ; NETO, ALMIR O. ; SANTOS, MAURO C. dos. Carbon supported hybrids nanostructures PtSn with CeO2 nanorods for Direct Ethanol Fuel Cells. In: REUNIAO ANUAL DA SOCIEDADE BRASILEIRA DE QUIMICA: CONSTRUINDO O AMANHA, 41., 21-24 de maio, 2018, Foz do Iguaçu, PR. Resumo... São Paulo: Sociedade Brasileira de Química, 2018.

    Abstract: New energetic sources have been the focus of current researches, including on fuel cells. This device has as its operating principle the conversion of chemical energy into electrical energy, making possible the use of renewable energy sources [1]. In the fuel cells operation are applied nanostructured electrocatalysts capable of oxidizing organic molecules such as ethanol [2]. This work was carried out using PtSn-based electrocatalysts with ceria nanorods (CeO2), synthesized by chemical reduction method via sodium borohydride [2], and supported on carbon Vulcan XC 72 (20% w/w). The synthesized materials have the following mass metal ratios: Pt/C; Pt3Sn1/ C and Pt3Sn1_20%NR/ C, with % of the Pt3Sn1 load replaced by ceria nanorods in the last nanomaterial, in order to reduce the costs of noble metals such as platinum. The evaluation of the activity for ethanol oxidation is given by polarization and power density curves, according to Figure 1. From the polarization curve it was observed that the Pt3Sn1_20%NR/ presented higher open circuit potential value (572 mV), and power density higher than the Pt/C composite material. The Pt3Sn1/C material presented a higher value of power density related to the others, but Pt3Sn1_20%NR/C generated a power density for ethanol oxidation relatively close to the best activity material, by the supply of oxygenated species improved the electrocatalytic activity for CO oxidation, making its application possible.

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  • IPEN-DOC 25500

    VIOLIN, K.B. ; GOIA, T.S.; BRESSIANI, A.H.A. ; BRESSIANI, J. . Alumina porous microspheres produced by snowballing technique, a new approach towards developing a suitable ceramic column for Tc-99m generators and other applications. In: INTERNATIONAL CONGRESS ON CERAMICS, 7th; CONGRESSO BRASILEIRO DE CERÂMICA, 62., June 17-21, 2018, Foz do Iguaçu, PR. Abstract... 2018. p. 1189-1189.

    Abstract: Tecnetium-99m generators requires an alumina column to adsorb and hold Molybdenum-99m, this alumina needs to have an increased specific surface area but if the particles are too small they can clog the glass column filter and impair the functioning of it. Considering manufacturing particles of spherical shape, micro-scale size of less than 1mm and loose arrangement still presents a challenge, despite the existence of many processes to obtain such structures involving several steps they lack pores. Microspheres are of great interest because they have a high packing capability, if combined with pores the possibility of possessing an increased surface area leads them to a wide range of applications. The microarchitecture represented by microporosity gives an adsorption potential to microspheres. Snowballing technique is a new process shown to be a suitable method for obtaining ceramic spheres without additives or binders. The method developed is based on a mechanical continuous movement of the particles, relying on the normal ability of the ceramic powders to aggregate themselves while rolling in a cylindrical container for long periods. The physical forces involved in the process, gravity, particle attraction, centripetal force and shocking transforms the ceramic aggregates into rounds with an asteroid like shape on its surface [1]. With this method it was possible obtain microspheres with 40% of porosity and rough surface measuring between 1mm to less than 250μm, according to the sieves used to separate them. This work presents the obtaining of alumina microspheres through Snowballing technique for use on Tc-99m generators. In an effort to broaden the range of application, architecture and microstructures are major aspects of concern hence the obtained microspheres can be also used for other purposes.

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  • IPEN-DOC 25499

    BABISK, M.P.; AMARAL, L.F.; RIBEIRO, L.S.; PRADO, U.S. ; MONTEIRO, S.N.; VIEIRA, C.M.F.. Effects of red mud on properties of red ceramics. In: INTERNATIONAL CONGRESS ON CERAMICS, 7th; CONGRESSO BRASILEIRO DE CERÂMICA, 62., June 17-21, 2018, Foz do Iguaçu, PR. Abstract... 2018. p. 1130-1130.

    Abstract: Alumina is obtained through the chemical processing of bauxite, known as Bayer process. During this process an insoluble residue denominated red mud is generated. In addition to silica, red mud has high levels of iron, sodium, calcium and other elements that can add important characteristics to ceramic products. In this sense, this work had the objective of evaluating the effect of utilization of red mud as raw material to traditional ceramic production. As raw materials, besides the red mud, two clays suitable for ceramic products manufacturing were used. The raw materials were submitted to physical, chemical, mineralogical and morphological characterization. The specimens were prepared by uniaxial pressing and sintered in temperatures at 850, 950 and 1050 °C. The relative dry density, firing linear shrinkage, water absorption and mechanical resistance were evaluated. It was demonstrated the real potential that this ceramic segment has in attempt to provide a technical and environmentally correct solution for utilization of red mud as raw material.

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  • IPEN-DOC 25498

    FERREIRA, T.S. ; CARVALHO, F.M.S.; GUEDES-SILVA, C.C. . Densification and microstructure of Si3N4-TiN ceramic composites. In: INTERNATIONAL CONGRESS ON CERAMICS, 7th; CONGRESSO BRASILEIRO DE CERÂMICA, 62., June 17-21, 2018, Foz do Iguaçu, PR. Abstract... 2018. p. 1018-1018.

    Abstract: Silicon nitride (Si3N4) is a ceramic material widely used in various structural applications at high temperatures owing to its excellent combination of mechanical and thermal properties. In order to increase the application field of silicon nitride, many researches have been developed to improve its fracture toughness and processing conditions. This work studies the sintering and microstructure of Si3N4-TiN composites, containing Al2O3 and Y2O3 as sintering aids Samples were obtained by the conventional method of mixing powders and sintered at 1750ºC / 1 hour and 1815ºC / 1 hour under nitrogen atmosphere. Density values of the different compositions were determined by the Archimedes method, reaching values between 96.9 and 98.0% of theoretical density, with an apparent porosity less than 0.5%, evidencing the efficiency of the sintering aids. Also, the sintered samples were analyzed by X-ray powder diffraction (XRD) and backscattered scanning electron microscopy (SEM). The results showed the materials developed a microstructure with TiN grains dispersed in a ?-Si3N4 matrix containing an amorphous intergranular phase, which was formed by the liquid phase solidification during the cooling step in the sintering process.

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  • IPEN-DOC 25497

    MELLO-CASTANHO, S.R. ; SILVA, J.P. ; CARDOSO, S.. Advanced processing strategies for the development of energy efficient devices with eco-friendly, natural materials. In: INTERNATIONAL CONGRESS ON CERAMICS, 7th; CONGRESSO BRASILEIRO DE CERÂMICA, 62., June 17-21, 2018, Foz do Iguaçu, PR. Abstract... 2018. p. 995-995.

    Abstract: The search for green technologies and the reduction of environmental impacts has become a constant in the scenario of technology options worldwide and in particular in countries with emerging economies that adapt very easily to the new paradigms of sustainability. Therefore, it is essential to develop new processing strategies for the green manufacture of ceramics to preserve natural sustainability and to generate clean and sustainable energy resources in remote areas. Therefore, the future of ceramic materials requires now to search for simple technological options that result in the use of low energy consumption and low emission of effluents to the environment and low cost. Processes involving mimicry, reuse, recovery, simple value-added products, in short, the development of the methodologies with strong ecological appeal can effectively aid to the economic turnover in manufacturing processes and it is one of the major challenges since the end of last century. This work, dials with the development and optimization of energy efficient processes to generate clean and sustainable energy sources such as the surface activation of natural nanotubes based on Palygorskite clay and the use of vegetable fiber Luffa Cylindrical as replica in porous burner technology. In the first case the green chemistry on surface activation by change Mg cations by radionuclides Ni, Sr, in stable condition shows a promisor potential using this raw material in the mitigation by immobilization of industrial nuclear rejects. In the second one, the controlled colloidal processing shows that it is possible to use silicates to fabricate burning gas light with luminescent characteristics, resistant to use in remote places that have not yet the electric energy available for lightning.

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  • IPEN-DOC 25496

    RESTIVO, T.A.G.; BECCARI, R.; DURAZZO, M. ; TELLES, V.; YAMAGATA, C. ; SILVA, A.C. ; TENORIO, J.A.S.; MELLO-CASTANHO, S.R.H.. Micrograded ceramic-metal composites. In: INTERNATIONAL CONGRESS ON CERAMICS, 7th; CONGRESSO BRASILEIRO DE CERÂMICA, 62., June 17-21, 2018, Foz do Iguaçu, PR. Abstract... 2018. p. 994-994.

    Abstract: Cermet materials are traditional materials for applications as catalysts and solid oxide fuel cell electrodes, i.e. zirconia-Ni and alumina-Ni. The paper shows new designed cermets and processes concerning primary to applications as thermal insulation materials with low emissivity. A new projected microstructure was obtained where dense regions (micropellets) rest inside the main porous pellet. The feature resembles a frozen hypercube (tesseract), therefore such architecture is called hyperpellet. In this way, the material shows both low thermal conductivity and emissivity. The processing method to obtain the hyperpellet cermet is based on 3-steps tape casting forming and 2-steps sintering technique. Metal (Ni) lamellae were prepared by a special mechanochemical process followed by sintering, which remain inside the main pellets as a dense region. The whole pellet is turned to be porous by employing pore former additives. All the constituents and porosity shapes are aligned along the flat disc plane. Micro pellets were also prepared into a rather regular flake morphology type through a suitable granulating process. The thermal conductivity is estimated for hyperpellet type discs and flake powders samples at 800oC by a flash diffusivimeter and compared with commercial ceramic insulation fiber blanked. Ceramography analyses show graded density regions and different constituents and pores with directional feature. Applications of such materials are foreseen as high temperature insulation materials and performant thermal radiation shields.

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  • IPEN-DOC 25495

    FUNGARO, D.A. . Processing, valorization and application of waste derived from silica and alumina. In: INTERNATIONAL CONGRESS ON CERAMICS, 7th; CONGRESSO BRASILEIRO DE CERÂMICA, 62., June 17-21, 2018, Foz do Iguaçu, PR. Abstract... 2018. p. 993-993.

    Abstract: Many industrial processes produce hazardous inorganic wastes which representing a large and increasing global ?ux. Majority of these wastes are dumped in landfills, ash ponds, lagoons and only a very small percentage is reutilized. The value-added applications to reduce/reuse these waste materials are important from the standpoint of sustainable development. Coal Combustion Products (CCPs), an industrial by-product generated during the combustion of coal, contains silica and alumina as the main components allowing their use as raw material for the synthesis of value-added materials. Brazil is the largest recycler of aluminum can in the world. The Al-containing waste generated by aluminum recycling activity can also be employed as a secondary raw material. In our studies, alkali hydrothermal reaction strategies have been proposed in order to obtain ef?cient adsorbent materials from FGD waste. Besides that, NaA zeolite was prepared by alkaline fusion method using aluminum waste from tertiary industry as Al-additive. Samples were characterized by different techniques such as XRF, XRD and cation exchange capacity. Therefore, recover the aluminum content of the hazardous waste and the recycling of CCPs represents a green and feasible alternative to highly valuable product synthesis

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  • IPEN-DOC 25494

    XAVIER, G.L. ; USSUI, V. ; OLIVEIRA, R.R. ; ROSSI, W. de ; LIMA, N.B. ; CASTRO, M.C.B. de . Evaluation of 3YTZP films deposited by electrophoretic deposition on titanium and irradiated with Nd:YAG laser. In: INTERNATIONAL CONGRESS ON CERAMICS, 7th; CONGRESSO BRASILEIRO DE CERÂMICA, 62., June 17-21, 2018, Foz do Iguaçu, PR. Abstract... 2018. p. 922-922.

    Abstract: Titanium is widely used in chemical, power generation, aerospace and biomedical industries because of its good mechanical properties, corrosion resistance and good biocompatibility. However, when is used, for example, in steam turbines is necessary increase the corrosion resistance at high temperature, or when is used in dentistry, when the metallic gray color compromise the aesthetics rehab, it becomes interesting to coat the titanium with a ceramic layers, and 3YTZP (Yttria-stabilized tetragonal zirconia) is suitable for this application, because it has good mechanical properties, good resistance to thermal cycles and good biocompatibility. The electrophoretic deposition is a suitable technique to obtain theses coatings. After deposition, is necessary achieve out the sintering of coating, but the sintering temperature of zirconia is about 1500 °C, and submit metal/ceramic joint to this temperature, cam bring on the degradation of metal. The solution to these problems is performing the sintering using a laser radiation. In this work it was studied the laser irradiation of zirconia ceramic coating deposited on titanium by electrophoretic deposition. Three series of irradiation tests were carried out using Nd:YAG (wavelength 1.06 μm) pulsed laser, energy of 0.5 J, pulse duration of 10 ms and rate of 10 Hz. During the tests, it was studied the influence of fluency, scanning speed and repetition of laser incidence. The repetition covered a range of 1 to 27 times. Prepared samples were characterized by optical and scanning electron microscopy, X-ray diffraction and scratch microindentation. The Xray results showed presence of tetragonal and monoclinic phases in the irradiated coatings. The optical and SEM results showed that densification increases with the increasing of number of laser incidence repetition and the scratch results showed that the irradiated samples presented more scratch resistance than non-irradiated samples.

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  • IPEN-DOC 25493

    ARAUJO, M.S. ; PRADO, U.S. ; GENOVA, L.A. . Soda lime silica glasses obtained from industrial solid wastes. In: INTERNATIONAL CONGRESS ON CERAMICS, 7th; CONGRESSO BRASILEIRO DE CERÂMICA, 62., June 17-21, 2018, Foz do Iguaçu, PR. Abstract... 2018. p. 885-885.

    Abstract: In this work, soda-lime glasses were produced using industrial solid wastes such as rice husk ash (RHA) and spent catalyst at the Petrochemical Fluid Catalytic Cracking units (ECAT) as alternative raw materials for silica (SiO2) and alumina (Al2O3). These correspond to two particularly valuable solid wastes, which are not well explored in the viewpoint of glass production. For the fabrication of vitreous samples we have also used, besides the wastes, commercial sodium carbonate and lime. Soda-lime glass containing the wastes was prepared by melting in alumina crucibles at 1600°C for 1 hour. Annealing treatments were performed for 3 hours at 530°C and then cooled to room temperature inside the furnace. The glass samples were characterized using XRF, XRD, ATG and visible spectrometer. The color measurement by (CIE) chromaticity diagram and optical transmission showed a good optical transparency of the glass samples, which confirmed the total vitrification. The results demonstrate that both can be used in their raw form (without treatment) replacing important raw materials, sources of Al2O3 and SiO2, essential for glass formation. The samples obtained presented amber color due to the presence of nickel (Ni²+ ion) from ECAT. Thus, the obtained glass is suitable for applications requiring low light transmittance such as colored glasses containers in general, which does not require complete visibility and transparency.

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  • IPEN-DOC 25492

    SILVA, D.L.C. ; SILVA, A.C. ; ARAUJO, M.S. ; MELLO-CASTANHO, S.R. . Structural reinforcement of Nb2O5 in soda-lime borosilicate glasses for nuclear waste immobilization. In: INTERNATIONAL CONGRESS ON CERAMICS, 7th; CONGRESSO BRASILEIRO DE CERÂMICA, 62., June 17-21, 2018, Foz do Iguaçu, PR. Abstract... 2018. p. 858-858.

    Abstract: The vitrification process has been used for high level nuclear waste (HLW) immobilization for more than 40 years around the word. However, there are still many difficulties involving the radiation effects in the glass matrixes as, for example, crackings that reduce their mechanical and chemical resistance. The impact of Nb2O5 addition in the CaO-Na2O-SiO2-B2O5 glass system was investigated. The glass samples, produced by melting method, were submitted to extreme chemical attacks like the alkaline ISO 695-1984 (E), the acid DIN 12116-1976 and characterized by X-ray diffraction (XRD), Fourier Transformed Infrared Spectroscopy (FTIR) and Raman Spectroscopy. XRD diffraction patterns obtained before the chemical attacks confirmed the vitreous character of the samples. Raman spectra and FTIR spectra obtained after the chemical attacks indicated that the Nb2O5 is well connected to the glass network, supported by the decrease in mass loss after the chemical attacks, as the the Nb2O5 content was raised in the samples. These results are indicative that the chemical resistance of the studied glasses can be improved by increasing the Nb2O5 content. These results show that the process is a promising alternative to produce new family of the appropriate glasses for nuclear wastes immobilization.

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  • IPEN-DOC 25491

    ARAUJO, M.S. ; SILVA, A.C. ; SILVA, D.L.C. e ; MELLO-CASTANHO, S.R. . Variations of Qn distribution in bioactive glasses containing strontium oxide and alumina. In: INTERNATIONAL CONGRESS ON CERAMICS, 7th; CONGRESSO BRASILEIRO DE CERÂMICA, 62., June 17-21, 2018, Foz do Iguaçu, PR. Abstract... 2018. p. 857-857.

    Abstract: The complexity in designing brand-new compositions as 45S5 Bioglass® is mainly due to the fact the more components you have, the more difficult it is to trace the relationship between composition, structure and bioactivity. Also, the properties of bioactive compositions reflect their ability to release a critical amount of different ions in the surrounding host tissue, creating or not favorable conditions to stimulate cellular processes. Since these properties and process of interaction are directly related to the glass network connectivity, which can be evaluated by Qn distribution and other medium-range structural techniques, the present research studied two series of compositions based on 45S5 however adding amounts of Al2O3 and SrO, to verify the impact of subtle compositional changes in the Qn distribution. The samples were obtained by melting (1500°C) and quenching and characterized by X-ray diffraction (XRD), differential thermal analysis (ATD), Fourier transform infrared (FTIR) and Raman spectroscopy. The initial results indicates that the matrix of typical bioactive phospho-silicate glasses which consists to be mostly Q², with some Q³, structures have been maintained in samples containing only SrO (0-2,7%mol). However, the samples containing both Al2O3 (2%mol) and SrO (0-2,7%mol) indicates that the addition of 1%mol SrO there is an increase of Q² in detriment of Q³, but then when the addition is up to 2,7%mol there is a decrease of Q² inversely proportional to Q³. Although these changes have been presented, none of the samples of both series presented cytotoxicity. Furthermore, studies on biocompatibility are being conducted to evaluate its impacts on their bioactivity.

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  • IPEN-DOC 25490

    OLIVEIRA, L.N.; ANDREETA, M.R.B.; SCHIMIDT, F.; ANTONIO, P.L. ; NASCIMENTO, E.O.; CALDAS, L.V.E. . Borate and silicate glasses as high-dose linear response dosimeters. In: INTERNATIONAL CONGRESS ON CERAMICS, 7th; CONGRESSO BRASILEIRO DE CERÂMICA, 62., June 17-21, 2018, Foz do Iguaçu, PR. Abstract... 2018. p. 829-829.

    Abstract: The search for new sensor materials is a continuous effort in materials engineering field. Aspects such as lower production costs and better sensitivity response, are of great technological importance and the main goals on this quest. The food and medical industries are the ones that benefit most from this research. In the food industry, for example, one of the processes that have been widely used is the application of high doses of gamma radiation in fruits and vegetables. Ionizing radiation destroys bacteria and fungi, increasing the shelf life of foods. In this way, there is the need for the development of dosimeters to monitor the dose used which can reach up to 20,000 times of the lethal ones for humans. Glasses are being considered for high-dose dosimetry applications, since its production costs are lower compared to other materials. However, it must fit another desirable characteristic, which is the linear response with respect to the radiation dose exposure. When glasses are exposed to high-dose gamma radiation, their optical absorption spectra changes. Although there is not a full agreement on the cause of that change in the optical spectra, it is believed that this is a combination of color centers produced by the entrapment of either electron-hole generated and/or due to some oxidized transition metal impurities. In this work, small rectangular pieces (1 x 1 x 4) mm3 of commercial soda-lime glasses, lithium and sodium diborates were irradiated with doses up to 10000 Gy, using a 60Co Gamma Cell-220 system. The samples were characterized by UV-Vis and Fourier Transform Infrared (FTIR) spectrometry. The dose-response data showed good linear relationships at 250 nm (R2=0.9972). The highest linearity was shown for lithium diborate, sodium diborate and commercial soda-lime glass, respectively. Based on the data presented, it is also shown that these glasses may be used as Yes/No in situ detectors.

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  • IPEN-DOC 25489

    SALES, J.N. ; POVEDA, P.N.S. ; GARCIA, R.H.L. ; VALENZUELA-DIAZ, F.R.; SILVA, L.A. . Effect of the incorporation of green lake clay in the property of impact and crystallinity of polypropylene. In: INTERNATIONAL CONGRESS ON CERAMICS, 7th; CONGRESSO BRASILEIRO DE CERÂMICA, 62., June 17-21, 2018, Foz do Iguaçu, PR. Abstract... 2018. p. 813-813.

    Abstract: Clays are extremely versatile materials, being present in many industrial activities. For applications in plastic materials it is necessary to pre-treat the clays by means of an organophilization process. In this work, Green Lake clay was treated with three different ammonium quaternary salts. The choice of the quaternary salt used in the later steps was performed based on the water swelling test results. The efficiency of organophilization of Verde Lago clay was verified by X-ray diffraction technique (XRD), verifying the basal distance between lamellae of the structure. Polypropylene composites were prepared with additions of 0.5% 1.0% and 2.0% by weight of the Verde Lago clay, which were characterized by means of the thermogravimetric test (TGA), to verify the actual clay content in each composite; differential scanning calorimetry (DSC) for analysis of degree of crystallinity and resistance to Charpy impact

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  • IPEN-DOC 25488

    GENOVA, L.A. ; SILVA, A.A. . Optimization of green machining of ZrO2 via a simple and small CNC mill. In: INTERNATIONAL CONGRESS ON CERAMICS, 7th; CONGRESSO BRASILEIRO DE CERÂMICA, 62., June 17-21, 2018, Foz do Iguaçu, PR. Abstract... 2018. p. 812-812.

    Abstract: Machining of sintered ceramics is a slow, costly process and is therefore not suitable for the production of parts with complex geometry. Therefore the machining of green or partially sintered (bisque) bodies becomes a highly interesting alternative. Recent advances in cad/cam technology have enabled the feasibility of green machining for the production of ceramics on both, large and custom scale. Characteristics of the green or partially sintered ceramic body (mechanical strength, hardness, density, etc.) define its machinability. At the same time the machining parameters (feed rate, depth of cut, and tool – rotation, material and geometry) can optimize this machinability, producing a low roughness and crack-free machined surfaces, and preventing chipping of the edges. In this work, isostatically pressed zirconia ceramics, green or partially sintered (800 to 1000 °C) were machined, with and without cooling liquid, in a simple and low cost CNC milling machine. Parameters such as the rotation, geometry and grain size of diamond impregnated mild steel tool, the feed rate and the depth of cut were varied and the design of experiments (DOE) method was applied to determine the influence of these parameters in the roughness of the machined surface, the formation of microcracks, the integrity of the edges, and the wear of tool. It was verified the benefit of the cooling in the wear of the tool and also in the finishing of the green and sintered surface. It was possible to reach a set of conditions related to the characteristics of the ceramic bodies and to the milling parameters that allowed obtaining surfaces with low roughness (Ra< 1.2 micron), free of cracks and without chipping of the edges.

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  • IPEN-DOC 25487

    YAMAGATA, C. ; LEME, D.R. ; MORAIS, V.R. . Novel method for the synthesis of Dy-doped yttrium disilicate phosphors. In: INTERNATIONAL CONGRESS ON CERAMICS, 7th; CONGRESSO BRASILEIRO DE CERÂMICA, 62., June 17-21, 2018, Foz do Iguaçu, PR. Abstract... 2018. p. 626-626.

    Abstract: Yttrium disilicate (Y2Si2O7) displays interesting structural properties because of its high refractoriness and stability in oxidizing environments. With its wide band gap and excellent thermal and chemical stability, it has been shown to be one of the most efficient host lattices for rare earth ions, which substitute Y3+ ions. When it is doped with different metallic ions, yttrium silicates exhibit attractive luminescent properties for potential applications, such as plasma displays, laser materials and high-energy phosphors. The use of solid-state reaction for yttrium disilicate synthesis shows disadvantages such as long times and temperatures of processing and formation of undesirable by-products. The objective of this work was to obtain silica (SiO2) nanoparticles by surfactant-assisted sol-gel process, using sodium silicate (Na2SiO3) as Si precursor, and its application on the synthesis of yttrium disilicate-based (Y2Si2O7) phosphors. Yttrium hydroxide was added to obtained silica nanoparticles, by precipitation from yttrium nitrate. Two precursors of yttrium disilicate were prepared: un-doped and doped with dysprosium 2,5 at %, (Y1,95Dy0,05Si2O7). The obtained powders were characterized by X-ray diffraction (XRD), to identify the polymorphic phases of yttrium disilicate, scanning electron microscopy (SEM), to observation of morphology. and luminescence spectroscopy. It was observed that ?-phase of Y2Si2O7 was obtained at 1300°C and showed sharper luminescence peaks in comparison with ?-phase. 7th International Congress on Ceramics & 62º Congresso Brasileiro de Cerâmica June 17-21, 2018, Foz do Iguaçu - PR - Brazil 626

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  • IPEN-DOC 25484

    MORAES, L.P.R. ; MARANI, D.; MACHADO, M.F.S. ; RODRIGUES, L.N. ; FONSECA, F.C. ; ESPOSITO, V.; SUN, Z.. Bottom-up and top-down approaches to the synthesis of 2D gadolinium-doped cerium oxide (CGO) at low temperature. In: INTERNATIONAL CONGRESS ON CERAMICS, 7th; CONGRESSO BRASILEIRO DE CERÂMICA, 62., June 17-21, 2018, Foz do Iguaçu, PR. Abstract... 2018. p. 543-544.

    Abstract: In the last decades, 2D nanosheets have been studied for their physicochemical properties, which are different from the bulk of the original material or any other nanostructure, therefore a challenging and exciting area of nanomaterial synthesis. Nanosheets can be used in the production of low cost electro-optics, stable highperformance batteries, high performance catalysts, etc. In general, there are two main approaches in the synthesis of nanomaterials: top-down and bottom-up. A top-down approach starts from a macroscopic material, which undergoes exfoliation or grinding to reduce its size to a nanometric scale. However, this type of process induces defects, compromising its properties. In the bottom-up method the nanostructures are built molecule by molecule, resulting in a more homogenous and controlled material. In this work, 2D nanostructures of gadolinium-doped cerium oxide (CGO) were synthesized by two simple and reproducible routes; both by aqueous precipitation induced by the hydrolysis of hexamethylenetetramine. The CGO materials synthesized were characterized by their composition, morphology and crystallographic characteristics. The combined experimental results indicated that different morphologies of 2D CGO can be obtained by controlling the synthesis parameters. The temperature of the reaction medium was decisive in the formation of a more homogeneous structure, establishing the optimum temperature to 10 ºC for the synthesis of nanosheets. The method of liquid exfoliation, with a solution of ethanol:water in an ultrasonic bath, was also established to obtain a suspension of nanosheets. Comparing the microscopic images of the materials synthesized by the top-down and bottom-up methods, it can be observed that the latter favours the formation of a more homogeneous nanostructure, leading to the obtention of exfoliated nanosheets with a shorter reaction and ultrasonic exfoliation time. Lead-based ceramics are widely used piezoelectric materials due to their excellent piezoelectric properties, but they are not environmentally friendly due to lead oxide toxicity. [1] Therefore, a number of studies have been carried out to improve electrical properties of different kind of ABO3 perovskites. [2] In the (1-x)K0.5Na0.5NbO3- xBaTiO3 system the effect of (K,Na) substitution by Ba decreases the temperature of the maximum dielectric permittivity and improves the dielectric properties. Consequently, this kind of materials can be used as an alternative candidate to replace conventional piezoelectric materials [3]. In this work, we present the synthesis and characterization of (1-x)K0.5Na0.5NbO3–xBaTiO3, (x= 0.03, 0.04, 0.05, 0.06, 0.07) based lead-free piezoelectric ceramics through the solid-state reaction route. Powders were mixed in different compositions with the final propose of obtaining extensive applications. It was observed that Ba2+ ions occupy the A sites of the perovskite structure, while Ti4+ ions replace Nb5+ ions at the B sites, resulting in the distortion of the perovskite structure. Additionally, for the highest BaTiO3 concentration a practically constant dielectric constant curve was registered from 20 to 500°C, whereas the loss tangent values ??were low. Lead-based perovskites are widely used for actuators, sensors and transducers due to their excellent piezoelectric properties. However, the toxicity of lead for the environment and human health led to focus research efforts on finding substitutes for these materials. One candidate is the Bi0.5Na0.5TiO3-Bi0.5K0.5TiO3 solid solution, due to its interesting properties attributed to the presence of a morphotropic phase boundary in the composition Bi0.5(Na0.8K0.2)0.5TiO3. It is known, that the synthesis methods of nanopowders, such as the sol-gel process, allow the control of grain size better that other methods. Consequently, this work focuses on the study of processing conditions and final properties of Bi0.5(Na0.8K0.2)0.5TiO3-based ceramics obtained by the sol-gel method. To obtain the desired phase, the reagents used were sodium acetate (CH3COONa), potassium acetate (CH3COOK), bismuth nitrate (Bi(NO3)3·5H2O) and titanium isopropoxide (Ti(OiPr)4). The acetates and nitrate were dissolved, separately, in glacial acetic acid. Titanium isopropoxide was dissolved in a solution of isopropanol and acetic acid. Acetates and nitrates were added dropwise. The mixture was stirred for one hour. Then, it was dried at 150 °C for 2 hours, and heat-treated at different temperatures (550 to 750 °C). The obtained powders were pressed uniaxially and sintered in the temperature range of 1000

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  • IPEN-DOC 25483

    STEIL, M.C.; GEORGES, S.; GELIN, P.; UHLENBRUCK, S.; FONSECA, F.C. . Gradual Internal Reforming process: development of catalyst layer for Solid Oxide Fuel Cells operating with methane and bioethanol. In: INTERNATIONAL CONGRESS ON CERAMICS, 7th; CONGRESSO BRASILEIRO DE CERÂMICA, 62., June 17-21, 2018, Foz do Iguaçu, PR. Abstract... 2018. p. 542-542.

    Abstract: In the gradual internal reforming (GIR) process, the water released by the electrochemical oxidation of hydrogen at the anode is used for the steam reforming of the fuel in the catalytic layer deposited over the anode of the SOFC. We have developed a highly active ceria-based catalytic layer that efficiently converts the primary fuel (ethanol or methane) into hydrogen using the electrochemically-generated steam. Ir/CGO catalyst was pretreated at 1173 K in He flow with less than 0.5 ppm O2 prior to catalytic testing. The catalyst consists of Ir nanoparticles (mean size of 4 nm in diameter) supported on the surface of sub-micron gadolinia-doped ceria particles and forms a continuous porous layer (~25 ?m thick) over the Ni-based anode. An anodesupported solid oxide fuel cell (SOFC) was continuously operated for more than 300 hours with direct methane or (anhydrous) ethanol, with a high current density. The catalytic layer associated with the GIR process avoids the carbon deposition on the anode material surface. Such results represent a significant advance towards the development of fuel-flexible SOFC operating with methane or ethanol.

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  • IPEN-DOC 25482

    MORAES, L.P.R. ; MACHADO, M. ; NUNES, L.; FONSECA, F.C. . Effect of iron doping nano-GDC synthesized via low temperature heterogeneous precipitation. In: INTERNATIONAL CONGRESS ON CERAMICS, 7th; CONGRESSO BRASILEIRO DE CERÂMICA, 62., June 17-21, 2018, Foz do Iguaçu, PR. Abstract... 2018. p. 541-541.

    Abstract: Gadolinium-doped cerium oxide exhibits beneficial properties for application as an electrolyte in electrochemical devices. However, it requires a high sintering temperature to obtain a fully dense body. In this study the effect of adding iron oxide to gadolinium-doped cerium (GDC) oxide to improve its sinterability and electrochemical performance was accessed. Doped GDC with different Fe molar concentrations (1, 3, 5 mol%) was successfully synthesized by a one-step aqueous precipitation method. Adding Fe 2 O 3 as a sintering aid increases the GDC densification and reduces its usual sintering temperature by ~300 °C. The microstructural and electrical properties of sintered pellets evidenced that using iron oxide as a sintering aid is a promising strategy to decrease sintering temperature of GDC.

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  • IPEN-DOC 25481

    FUJIMOTO, T.G. ; MUCCILLO, E.N.S. ; CARVALHO, L.A.. Ionic conductivity of Sr- and Mg-doped lanthanum gallate with La1.55Sr0.55Ga3O7+delta addition. In: INTERNATIONAL CONGRESS ON CERAMICS, 7th; CONGRESSO BRASILEIRO DE CERÂMICA, 62., June 17-21, 2018, Foz do Iguaçu, PR. Abstract... 2018. p. 537-537.

    Abstract: Sr- and Mg-doped lanthanum gallates are solid electrolytes with ionic conductivity higher than that of the traditional yttria-stabilized zirconia. Moreover, doped lanthanum gallates exhibit wide electrolytic domain and good chemical stability. The combination of their properties turns this compound a promising candidate for application in solid oxide fuel cells operating at intermediate temperatures (550-750°C). In this work, small amounts of La1.55Sr0.55Ga3O7+δ was added to doped lanthanum gallate and the effects of the additive on electrical properties of the base material were investigated by the impedance spectroscopy technique. The X-ray diffraction patterns of sintered specimens show the characteristic reflections of the perovskite-type phase, along with low-intensity diffraction peaks of the commonly detected impurity phases. The impedance spectroscopy diagrams reveal the high-frequency arc due to the bulk resistivity besides a strong overlap of the grain boundary arc with that of the electrode. The grain resistivity decreases for increasing amounts of La1.55Sr0.55Ga3O7+δ.

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  • IPEN-DOC 25480

    OLIVEIRA, G.L. ; ANDREOLI, M. ; GENOVA, L.A. . Porous TiO2 microspheres synthesized by internal gelation method. In: INTERNATIONAL CONGRESS ON CERAMICS, 7th; CONGRESSO BRASILEIRO DE CERÂMICA, 62., June 17-21, 2018, Foz do Iguaçu, PR. Abstract... 2018. p. 535-535.

    Abstract: Titanium dioxide (TiO2) combines an interesting set of characteristics and properties that allow its application in a wide range of areas, including pigments, biomaterials, catalysis, sensors, drugs, ion exchange, etc. TiO2 is the most promising for photocatalysis among the semiconductors due to its high photocatalitic performance, its elevated thermal and chemical stability, and low cost. Recently, it has been intensively studied as a photocatalyst in advanced oxidative processes (AOPs) for the treatment of industrial effluents containing organic pollutants. The objective of this work was to obtain porous TiO2 microspheres from TiCl4 by the internal gelation method, in order to explore this geometry in the optimization of photocatalyst reactors, such as column reactors or fluidized bed reactors (for gaseous effluents), as well as ease of separation. The obtained microspheres were calcined in different conditions, between 550 and 900 °C for one hour, and characterized with respect to their size and sphericity (SEM), crystalline phases present (XRD), specific surface area and porosity (BET/BJH). The effect of the variables of the internal gelation process and of the heat treatment on the characteristics of the microspheres obtained was evaluated. A specific surface area of the sample calcined at 550 °C was of 98.7 m2/g, while the area for the sample calcined at 900 ° C was of 3 m2/g. The calcined microspheres above 800 °C presented two cystaline phases, anatase and rutile, whereas those calcined at lower temperatures presented only the anatase phase. These microspheres showed photocatalytic capacity (degradation of methylene blue) comparable to the Aeroxide TiO2-P25 produced by Evonik. 7th International Congress on Ceramics & 62º Congresso Brasileiro de Cerâmica June 17-21, 2018, Foz do Iguaçu - PR - Brazil 535

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  • IPEN-DOC 25479

    LAZAR, D.R.R. ; CAMARGO, E.F. de ; CORDEIRO, G.L. ; USSUI, V. ; OLIVEIRA NETO, A. . Evaluation of tin-doped indium oxide synthesized by Pechini polymeric precursor route as eletrocatalyst support for ethanol electrooxidation. In: INTERNATIONAL CONGRESS ON CERAMICS, 7th; CONGRESSO BRASILEIRO DE CERÂMICA, 62., June 17-21, 2018, Foz do Iguaçu, PR. Abstract... 2018. p. 514-514.

    Abstract: The generation of electric energy with low environmental impact and efficiency is a motivation for the development of fuel cells systems which traditionally are fed by gaseous hydrogen. The interest for the use of methanol and ethanol has also been considered in order to reduce the infrastructure required to store and supply the fuel. However, the low alcohol electrooxidation kinetics is a problem. In the case of polymeric membrane fuel cell, platinum is the state-of-the art electrocatalysts used to solve this drawback. Carbon black is always employed as platinum support, but problems related to low corrosion resistance and poisoning by absorption of CO species reduces the fuel cell performance with time. In order to improve electrocatalysts efficiency, some metal oxides have been proposed as candidate for oxidation resistant catalysts support. Inspired by the good electrical conductivity of tin doped indium oxide (ITO) for some applications such as liquid crystal displays, ITO has been considered as platinum support. In the present work, ITO powders (10wt% SnO2 – 90wt% In2O3) were synthesized by the Pechini method. Produced powders were characterized by TG/DTA analysis, X-ray diffraction, energy-dispersive X-ray spectroscopy and scanning electron microscopy. Pt supported on ITO was prepared by borohydride reduction method. Pt deposited on commercial ITO and on carbon black (Vulcan) were also prepared for comparison purposes. Electrochemical behavior of ethanol electrooxidation reaction (EOR) was performed using cyclic voltammetry and chronoamperometry techniques. Results showed that ITO powders prepared with the molar ratio citric acid/metals 1:1, followed by calcination at 600oC, are porous and soft aggregate composed by nanoparticles with cubic structure and established nominal composition. This material allowed an electrochemical behavior similar to commercial ITO due to its particle size and suitable agglomerate porosity for ethanol electrooxidation reaction.

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  • IPEN-DOC 25478

    FLORIO, D.Z. de; TINTI, V.B.; FONSECA, F.C. . Synthesis and magnetic characterization of ni nanoparticles in ceramic matrix. In: INTERNATIONAL CONGRESS ON CERAMICS, 7th; CONGRESSO BRASILEIRO DE CERÂMICA, 62., June 17-21, 2018, Foz do Iguaçu, PR. Abstract... 2018. p. 512-512.

    Abstract: The production of nanoparticles by exsolution is a technique that has been extensively researched and improved recently. Exsolved particles have superior properties when compared to deposited particles. The method of exsolution consists in the reduction of previously solubilized ions in a matrix, giving rise to particles strongly attached to the substrate. Materials with compositions (La1-xSrx)z(Cr1-yNiy)O3-? (x and y = 0%, 5%, 10%, 15% and 20%, z = 100% and 80%) were synthesized using the polymerization of complexes technique. The resin produced in the synthesis process was analyzed using thermal analysis and the calcination temperature was determined to be 900 ° C. The X-ray diffraction technique was used to characterize structures and identify the present phases. All samples were reduced to create nanoparticles of metallic nickel by exsolution. Magnetic analysis was conducted to determine the magnetic behavior of the produced materials. Non-stoichiometric materials were synthesized to verify the influence of different stoichiometry in the exsolution process. Non-stoichiometric A site impaired the solubilization of Ni and Sr in the lanthanum chromite structure. All samples with dopants showed a decrease in the temperature of Neel of the lanthanum chromite. However, the reduction treatment caused an increase in the Neel temperature when compared to the oxidized samples. This is indicative of the decrease in nickel concentration in solid solution, a result consistent with the exsolution mechanism. Using the measurements of magnetism, it was possible to verify the mechanism of exsolution and mass fraction of metallic nickel for each sample. Using electron microscopy techniques, it was possible to detect the presence of nanoparticles after the reduction treatment with a diameter of approximately 20 nm. When performing a local chemical analysis using a transmission electron microscope, it was possible to verify that the particles in question are of metallic nickel.

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  • IPEN-DOC 25477

    RAMANATHAN, L.V. . Scope for using ceramic coatings in the nuclear field. In: INTERNATIONAL CONGRESS ON CERAMICS, 7th; CONGRESSO BRASILEIRO DE CERÂMICA, 62., June 17-21, 2018, Foz do Iguaçu, PR. Abstract... 2018. p. 453-453.

    Abstract: A wide range of coatings to protect or enhance specific properties of the substrate are presently available and processes to apply these coatings are well established. Surprisingly, use of coatings in the nuclear field has received very little attention. This presentation will highlight the scope for using ceramic coatings mainly on nuclear fuel claddings and reactor components. All components and structures inside commercial nuclear reactor pressure vessels are exposed to high levels of irradiation at high water/steam pressures and temperatures. Despite caution exercised during material selection, degradation in mechanical properties under irradiation has been the primary cause for accidents or unplanned shutdowns in the nuclear industry. Qualification of a coated material is further complicated as two different materials are involved, besides the interface, and is the main reason for scant use of coatings in the nuclear field. Nevertheless, the following instances exemplify the use of ceramic coatings: (a) Prevention of accelerated corrosion of zircaloy at high temperature (accident situation) is extremely important to avoid generation of H2 (cause of the explosions in the 3 reactors of the Fukushima Nuclear Plant in Japan). Had the zircaloy cladding been coated with alumina, the explosions could have been averted by delaying H diffusion through the alumina layer and gaining time to take other preventative measures. (b) At normal reactor operating temperatures, ZrH2 forms in the cladding causing blisters, cracking and embrittlement. This can be mitigated by using PVD-ZrO2 coatings with low hydrogen permeability. (c) Fuel rods swell during irradiation due to build-up of fission products, severely compromising reliability of the cladding. One option to prevent fuel-cladding interactions is to coat the inner walls of the cladding with a TiN-based coatings. Besides these instances, other applications for ceramic coatings will be presented and discussed.

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  • IPEN-DOC 25476

    BENTO, R.T. ; SZURKALO, M. ; OLIVEIRA, E.C. ; CORREA, O.V. ; PILLIS, M.F. . UV–Vis photocatalytic performance of the S-doped TiO2 and TiO2 thin films for water treatment. In: INTERNATIONAL CONGRESS ON CERAMICS, 7th; CONGRESSO BRASILEIRO DE CERÂMICA, 62., June 17-21, 2018, Foz do Iguaçu, PR. Abstract... 2018. p. 421-421.

    Abstract: TiO2 films have been widely used as catalysts in oxidative processes in order to degrade organic contaminant. However, without the presence of a dopant material, its photocatalytic activity is limited only in the region of ultraviolet radiation (UV), due to its high-energy band gap. In this present research, anatase TiO2 thin films were grown on borosilicate substrates by metalorganic chemical vapor deposition (MOCVD) at 400ºC. To make the semiconductor active in the visible light region, sulfur doped TiO2 films were prepared by means of a thermochemical treatment carried out in a tubular oven, under atmosphere of H2S at 50ºC for 60 minutes. The films were characterized by XRD, AFM, FE-SEM and XPS technique. The photocatalytic behavior of the films was evaluated by methyl orange dye degradation under UV-Vis irradiation for 300 minutes. The photocatalytic tests were realized in a reactor illuminated by two tubular UV lamps (352 nm), and in a reactor illuminated by visible light (400-700 nm) on different intensities, both containing 40 mL of the dye solution. The results showed that the S-TiO2 films present promising photocatalytic efficiency. Without the presence of the catalyst, there was no degradation of the methyl orange dye under UV-Vis irradiation. Non-doped TiO2 films do not exhibited photocatalytic activity under visible light. It was possible to observe that the visible light intensity influences the doped films photocatalytic performance.

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  • IPEN-DOC 25475

    SHINZATO, M.C.; ALMEIDA, T.M.; GUEDES-SILVA, C.C. ; SILVA, E.F.S.. The potential use of the alkaline waste from the aluminum industry as aluminum and silicon source in the geopolymerization process. In: INTERNATIONAL CONGRESS ON CERAMICS, 7th; CONGRESSO BRASILEIRO DE CERÂMICA, 62., June 17-21, 2018, Foz do Iguaçu, PR. Abstract... 2018. p. 353-353.

    Abstract: The objective of this work was to evaluate the alkaline waste of the aluminum industry (red mud) as a source of aluminum and silicon in the production of geopolymers. These elements are essential to form the tetrahedrally coordinated structures of the geopolymers. The characteristics of the studied material were compared with those of metakaolinite, since the latter is considered an excellent geopolymer precursor material. Samples of the dehydrated red mud were supplied by a Brazilian primary aluminum industry. This material was chemically (X-ray fluorescence) and mineralogically (X-ray diffraction) characterized. Samples of metakaolinite and red mud (original and pretreated by heating at 700 oC/2 h) were subjected to a leaching test with a 12 mol L-1 NaOH solution to determine the contents of reactive silica and alumina fractions. The Si4+ and Al3+ contents of the filtered solutions were determined by plasma optical emission spectrometry. The red mud has a total of 21.7% Al2O3 and 16.6% SiO2, and it is composed by the mineral phases: quartz, hematite, kaolinite, goethite, gibbsite, anatase, sodalite, gypsum. The contents of the leached fractions of Al3+ and Si4+ of the original red mud were respectively 3.9% and 0.7%. The red mud heated sample presented higher contents of Al3+ (8.5%) and Si4+ (6.6%). It was verified that the heating process increased the concentrations of Al and Si fractions available for the geopolymerization reactions. These values are closer to those obtained for metakaolinite (9.2% Al3+ and 4.4 Si4+). The X-ray diffraction data of the heated red mud revealed that the hydroxylated phases became amorphous and promoted the formation of metakaolinite. Thus, the red mud has important components, which when heated, increase the Al and Si availability for the geopolymerization reactions. The other components of the red mud, being less reactive, serve as aggregates for the geopolymer composition.

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  • IPEN-DOC 25473

    MARCHI, J.; BORGES, R.; ZEZELL, D.M. ; LIMA, C.A. . Influence of Na2O/CaO ratio on the dissolution kinetics of biocompatible glasses. In: INTERNATIONAL CONGRESS ON CERAMICS, 7th; CONGRESSO BRASILEIRO DE CERÂMICA, 62., June 17-21, 2018, Foz do Iguaçu, PR. Abstract... 2018. p. 136-136.

    Abstract: Glass dissolution and bioactivity are two phenomena strictly related to each other in biocompatible glasses. By controlling the glass dissolution, the ions of the glass matrix can be released on controlled manner, and the glass can play a role as a resorbable or bioactive biomaterial, depending on the ratio of the oxides into glass composition. In this work, we studied the glass dissolution of three compositions of biocompatible glasses with potential applications in regenerative medicine. Glasses based on the system 47SiO2-(37- x)Na2O-(10+x)CaO containing 6 wt% P2O5 (x = 0, 5 and 10) were obtained by melt-quenching at 1500°C/1h. The biocompatibility of these glasses was performed by immersion in a simulated body fluid solution up to 21 days, and then the glasses were characterized by XRD, FTIR, Raman spectroscopy and SEM. Glass dissolution kinetics essay was carried out in buffer solution at pH 7 and 37°C, and the ionic concentration of the leached ions was measured by ICP-OES. The results suggested that the speciation of silicate Qn units plays an important role on dissolution kinetics at the very first time of dissolution, which, in turn, can increase bioactivity. On the other hand, once the hydroxyapatite layer is nucleated on the glass surface, it acts as a barrier between the glass and the aqueous medium, decreasing the dissolution rate. The overall results give new insights about the relationship between dissolution and bioactivity, and how to approach dissolution in bioactive glasses.

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  • IPEN-DOC 25472

    USSUI, V. ; MIRANDA, R.B.P.; LIMA, N.B. ; LAZAR, D.R.R. ; MARCHI, J.; CESAR, P.F.. Microstructural evaluation of Y-TZP/TiO2 composite. In: INTERNATIONAL CONGRESS ON CERAMICS, 7th; CONGRESSO BRASILEIRO DE CERÂMICA, 62., June 17-21, 2018, Foz do Iguaçu, PR. Abstract... 2018. p. 124-124.

    Abstract: Y-TZP ceramics, known as yttria stabilized tetragonal zirconia polycrystals are employed as dental implants due to its excellent mechanical properties, good esthetic and high biocompatibility. However, Y-TZP is bioinert and consequently has low interaction with bone tissue. One alternative to improve its bioactivity is the addition of a bioactive ceramic to the Y-TZP matrix. Titania (TiO2) is known to have good biocompatibility and was chosen to be added to the 3Y-TZP in order to improve such property. Synthesis was performed through coprecipitation of metal salts in a ammonium hydroxide solution, followed by washing, drying, milling and calcination. Ceramic powders were prepared to have up to 20 mol% of TiO2 over Y-TZP matrix. The powders were uniaxially pressed and sintered at dilatometer and in a tubular furnace from 1200 to 1500?C Ceramic pellets were characterized by X-ray diffraction with Rietveld refinement and scanning electron microscopy with field emission gun. Dilatometric analysis showed that samples containing TiO2, presented its higher densities for temperatures about 1300 C and a volume expansion at higher temperatures, with lower densities. Tetragonality, expressed as the relation between c/a lattice parameters measured after Rietveld refinements, in general, increases with increasing TiO2 content for all temperatures. Variations of crystal structure, density and cell volume could be related with TiO2 amount and sintering temperature. The overall results indicates that the crystalline structure of the Y-TZP/TiO2 composite was altered by the addition of titania.

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  • IPEN-DOC 25471

    ARATA, A. ; USSUI, V. ; LIMA, N.B. ; LAZAR, D.R.R. ; SOUZA, G.M.D. de; MARCHI, J.. Effect of sintering conditions of zirconia-yttria-titania-based ceramics composite on the densification and microstructure. In: INTERNATIONAL CONGRESS ON CERAMICS, 7th; CONGRESSO BRASILEIRO DE CERÂMICA, 62., June 17-21, 2018, Foz do Iguaçu, PR. Abstract... 2018. p. 123-123.

    Abstract: Glass dissolution and bioactivity are two phenomena strictly related to each other in biocompatible glasses. By controlling the glass dissolution, the ions of the glass matrix can be released on controlled manner, and the glass can play a role as a resorbable or bioactive biomaterial, depending on the ratio of the oxides into glass composition. In this work, we studied the glass dissolution of three compositions of biocompatible glasses with potential applications in regenerative medicine. Glasses based on the system 47SiO2-(37- x)Na2O-(10+x)CaO containing 6 wt% P2O5 (x = 0, 5 and 10) were obtained by melt-quenching at 1500°C/1h. The biocompatibility of these glasses was performed by immersion in a simulated body fluid solution up to 21 days, and then the glasses were characterized by XRD, FTIR, Raman spectroscopy and SEM. Glass dissolution kinetics essay was carried out in buffer solution at pH 7 and 37°C, and the ionic concentration of the leached ions was measured by ICP-OES. The results suggested that the speciation of silicate Qn units plays an important role on dissolution kinetics at the very first time of dissolution, which, in turn, can increase bioactivity. On the other hand, once the hydroxyapatite layer is nucleated on the glass surface, it acts as a barrier between the glass and the aqueous medium, decreasing the dissolution rate. The overall results give new insights about the relationship between dissolution and bioactivity, and how to approach dissolution in bioactive glasses.

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ATENÇÃO!

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

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

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

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


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