• 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.

  

• 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.

  

• 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.

  

• 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.

  

• 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.

  

• 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.

  

• 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.

  

• 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.

  

• 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.

  

• 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.

  

• 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.

  

• 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.

  

• 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).

  

• 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.

  

• 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.

  

• 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.

  

• 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.

  

• 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.

  

• 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).

  

• 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.

  

• 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.

  

• 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.

  

• 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.

  

• 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.

  

• 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.

  

• 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.

  

• 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.

  

• 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.

  

• 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.

  

• 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.

  

• 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.

  

• 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.

  

• 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.

  

• 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.

  

• 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.

  

• 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.

  

• 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

  

• 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.

  

• 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.

  

• 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.

  

• 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.

  

• 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.

  

• 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

  

• 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.

  

• 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

  

• 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

  

• 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.

  

• 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.

  

• 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.

  

• 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

  

• 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.

  

• 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.

  

• 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.

  

• 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.

  

• 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.

  

• 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.

  

• 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.

  

• 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.

  

• IPEN-DOC 25470

  SOLANO, A.; ARATA, A. ; LIMA, N.B. ; USSUI, V. ; LAZAR, D.R.R. . Y-TZP dental ceramics: Sintering process improvement using microwave energy. In: INTERNATIONAL CONGRESS ON CERAMICS, 7th; CONGRESSO BRASILEIRO DE CERÂMICA, 62., June 17-21, 2018, Foz do Iguaçu, PR. Abstract... 2018. p. 122-122.

  Abstract: Conventional sintering techniques of yttria-tetragonal zirconia polycrystals (Y-TZP) ceramics have presented limitations regarding the sintering time and temperature, increasing the cost of the final dental and biomedical products. Herein, microwave sintering comes to be an interesting alternative by providing fast heating, high densification and grain size control, decreasing the total time to produce the ceramic. The aim of this study was to compare the effect of microwave sintering of a pre-sintered commercial dental Y-TZP ceramic and a Y-TZP produced from powders synthesized in a laboratory scale by the copreciptation route. Densification, fracture toughness, grain size and crystalline phase quantification of sintered samples were evaluated. The synthetized and commercial (Vita Zahnfabrik, Germany) groups were submitted to 1450 °C and 1350 °C sintering temperature for 15, 30 and 60 minutes. Both groups sintered at 1450°C for 15 minutes and 30 minutes showed the higher densification results (98% concerning to theoretical density). All the samples sintered at 1350 °C achieved 96TD% independent of the sintering time. XRD quantitative phase analysis indicates that samples are formed by 89% tetragonal and 11% cubic phases (0,833 standard deviation), except for the group prepared from coprecipitated powders sintered at 1450oC for 30 minutes, that presented 79% and 21% of tetragonal and cubic phases, respectively. Therefore, microwave sintering allows the preparation of dense ceramics with high tetragonal phase content. The sintering time and temperature induced differences at the Y-TZP microstructure.

  

• IPEN-DOC 25469

  USSUI, V.; MANARAO, D.S. ; CORDEIRO, G.L.; TERTULIANO, A.J.O.; MACHADO, I.F. ; LAZAR, D.R.R.; CESAR, P.F. . Evaluation of reduced graphene oxide -reinforced zirconia ceramics processing conditions. In: INTERNATIONAL CONGRESS ON CERAMICS, 7th; CONGRESSO BRASILEIRO DE CERÂMICA, 62., June 17-21, 2018, Foz do Iguaçu, PR. Abstract... 2018. p. 120-120.

  Abstract: Yttria tetragonal zirconia polycrystal (Y-TZP) has been widely used as dental and orthopaedic implants. However, the lack of stability of the tetragonal phase in water environment can induce damages on the ceramic surface due to the transformation into the monoclinic phase. The reduction of ceramic grain size can avoid this phase transformation, despite the loss of transformation toughening benefits. In order to minimize this drawback, the incorporation of a second phase into the zirconia matrix has been recently considered. The aims of the present contribution were to establish the procedure of ceramic processing of reduced graphene oxide -reinforced zirconia ceramics and to verify its influence on hardness and fracture toughness. The composite production included several steps: (a) synthesis of Y-TZP powder by coprecipitation route, (b) synthesis of graphene oxide from chemical exfoliation of graphite (modified Hummer’s method) followed by reduction with ascorbic acid, (c) sonication of reduced graphene oxide in Y-TZP suspension followed by drying (d) uniaxial pressing and (e) sintering in a conventional tubular furnace (Argon/ 4%hydrogen atmosphere) and spark plasma sintering (SPS). The concentration of rGO in Y-TZP was fixed between 0.01 to 2.0 wt%. Sintered samples were characterized by X-ray diffraction, scanning electron microscopy, density measurements, and Vickers method for hardness and fracture toughness determination. Results showed that the procedure stablished for dispersion of rGO in Y-TZP allowed a good physical homogeneity of rGO and Y-TZP. Regarding the sintering procedure it was observed that conventional sintering in a controlled atmosphere was not effective for ceramic densification due to microcrack formation at the ceramic surface. Employing 0.05 rGO wt% in Y-TZP ceramic associated to spark plasma sintering at 1350oC allowed density higher than 98%DT and hardness and fracture toughness up to 14.4 GPa and 7.8 MPam1/2.

  

• IPEN-DOC 25467

  NASCIMENTO, S.F.; RODAS, A.C.D.; CARVALHO, F.M.S.; HIGA, O.Z. ; GUEDES-SILVA, C.C. . Silicon nitride ceramics with SiO2, SrO and Al2O3 additions for bone replacements. In: INTERNATIONAL CONGRESS ON CERAMICS, 7th; CONGRESSO BRASILEIRO DE CERÂMICA, 62., June 17-21, 2018, Foz do Iguaçu, PR. Abstract... 2018. p. 24-24.

  Abstract: The excellent mechanical properties of silicon nitride ceramics combined with their osseointegration ability and good image characteristics have increased their application potential as orthopedic and dental implants. In this work, we investigated the densification, microstructure and mechanical properties of silicon nitride with SiO2, SrO and Al2O3 additions (90Si3N4-6SiO2-4SrO, 90Si3N4- 6SiO2-3.86SrO-0.14Al2O3, 80Si3N4-10SiO2-10SrO, 80-Si3N4-10SiO2- 9.625SrO-0.375Al2O3, 80Si3N4-12SiO2-8SrO, 80-Si3N4-12SiO2-7.7SrO- 0.3Al2O3, in wt.%). This oxides combination should aid the sintering process and promote an intergranular phase with great in vivo reactivity in view of its importance in the new bone formation process. Hence, six different compositions were prepared by the conventional sintering method. Samples were ground, pressed and sintering at 1815o C for 1 hour under nitrogen atmosphere. The apparent density, phase and grain distributions as well as the hardness and fracture toughness were determined by means of Archimedes’ method, scanning electron microscopy (SEM), X-ray powder diffraction (XRD) and Vickers’ method. Also, in vitro test of cytotoxicity was performed for a preliminary biological evaluation. The results shown that samples reached ca. 97% of theoretical density and total beta-Si3N4 transformation. Hardness and fracture toughness values of 10 GPa and 7 MPa.m1/2, respectively, were obtained for all samples which were non-cytotoxic, suggesting their great potential for bone replacements in orthopedic surgeries and implantology.

  

• IPEN-DOC 25430

  LEAL NETO, R.M. ; BARDELLA, F. ; RODRIGUES, A.M.. CrystalWalk AR: estruturas cristalinas e realidade aumentada. In: CONGRESSO BRASILEIRO DE ENGENHARIA E CIÊNCIA DOS MATERIAIS, 23., 04-08 de novembro, 2018, Foz do Iguaçu, PR. Resumo... 2018. p. 9042-9042.

  Abstract: Este trabalho documenta o processo de especificação, desenvolvimento e prototipação de uma plataforma de ensino-aprendizagem de estruturas cristalinas, intitulada CrystalWalk AR (de Augmented Reality em inglês), que se utiliza a plataforma experimental de computação holográfica Microsoft Hololens. Desde que foi lançado em meados de 2016, o software CrystalWalk (CW) vem se consolidando como alternativa aos softwares cristalográficos tradicionais, uma vez que é capaz de gerar representações visuais tridimensionais de estruturas cristalinas de modo didático e interativo, mais afeito a estudantes e não especialistas em cristalografia. A mesma motivação original do desenvolvimento do CW vigora no atual trabalho, ou seja, a percepção de deficiências nas ferramentas de ensino-aprendizagem empregadas no estudo de estruturas cristalinas. O correto entendimento deste tema demanda habilidade associada à visualização em três dimensões, além de conceitos nem sempre bem explorados pelos livros didáticos da área. Apesar de modelos físicos tradicionalmente serem utilizados para tentar contornar essas limitações, sua natureza material impõe restrições, ao contrário dos modelos virtuais. Com a disseminação do uso do CW evidenciou-se seu vasto potencial imersivo em ambientes intermediários de virtualidade – particularmente a Realidade Aumentada (AR) – sobretudo devido à falta de maturidade e ao alto custo das tecnologias comercialmente disponíveis. Baseado na arquitetura original do CW, a aplicação CrystalWalk AR (CW-AR) foi desenvolvido para o Microsoft Hololens integrando-se a plataforma Unity para desenvolvimento de aplicações 3D e o framework Vuforia para desenvolvimento de aplicações de Realidade Aumentada (AR). Assim, a partir do uso de SmartTags é possível ‘agarrar’ estruturas cristalinas, integrando modelos gerados a partir do CW a um ambiente holográfico imersivo. Sem os limites de um ambiente bidimensional dentro de um monitor, alunos e professores puderam exibir, ampliar, transladar e rotacionar projeções holográficas tridimensionais de estruturas e defeitos cristalinos simultaneamente à realidade física, posicionando, dimensionando e transitando por entre diferentes modos de visualização como a representação de pontos de rede, motivo, célula unitária e estrutura cristalina. Diferentemente do CW, entretanto, o CWAR possui foco em desenvolvimento de propriedade intelectual, cuja solução é composta por conteúdo autoral, hardware e software de códigos fechado. Estudos preliminares do CW-AR com alunos e professores sugerem benefícios tangíveis relacionados à interação e à imersão, proporcionando uma melhor integração de interfaces multimodais (mais que uma forma de interação), quando comparados com sistemas tradicionais de Realidade Virtual. No CW-AR destacam-se também potenciais melhorias relacionadas ao custo e à complexidade operacional.

  

• IPEN-DOC 25429

  VARCA, G.H.C. ; FAZOLIN, G.N. ; FERREIRA, A.H.; OLIVEIRA, J.P.R. de ; MARQUES, F.; LUGAO, A.B. . The effect of radiation dose rate over the formation of protein-based nanoparticles for nanosized delivery of chemo and radiotherapeutics. In: CONGRESSO BRASILEIRO DE ENGENHARIA E CIÊNCIA DOS MATERIAIS, 23., 04-08 de novembro, 2018, Foz do Iguaçu, PR. Resumo... 2018. p. 8875-8875.

  Abstract: Recent studies demonstrated the development of papain and bovine serum albumin nanoparticles using gamma radiation (10 kGy) in presence of 20-30% (v/v) ethanol. With the purpose of producing stable and well defined nanocarriers, this work aims to determine the influence of different dose rates over protein nanoparticle formation. For this purpose, papain and BSA nanoparticles were synthetized in phosphate buffer (50 mM, pH 7.2) and ethanol (20-30%, v/v) using a radiation dose of 10 kGy and dose rate of 0.8, 2, 5 and 10 kGy.h-1. After irradiation, samples were evaluated by dynamic light scattering, fluorescence and proteolytic activity to verify the size, secondary structure and monitoring of the enzymatic activity, respectively. For papain nanoparticles it was observed that the dose rate did not influence the particle size formation, however crosslinking evidenced by bityrosine showed that samples irradiated at 0.8 and 5 kGy.h-1 presented higher bityrosine levels. On the other hand, BSA nanoparticles presented different results if compared to papain NPs. Different dose rates caused different and non-linear size increase for each condition, following the order: 5 > 10 > 0.8 > 2 kGy.h-1. However, in terms of crosslinking formation, a linear increase was registered, as at 0.8 kGy.h-1 the smallest signal was achieved, whereas at 10 kGy.h- 1 the highest signal was recorded. In conclusion, BSA nanoparticles were more sensitive to different radiation dose rates than nanopapain. Optimized results in terms of size increase and higher bityrosine levels were observed for the samples irradiated at 5 kGy.h-1, in which nanoparticle formation will occur faster if compared to the synthesis carried out under distinct conditions. As final applications of the system concert their use for the delivery of chemo or radiotherapeutics, the loading of paclitaxel, a well-known chemotherapeutic agent, and radiolabeling with tecntetium- 99m, a radioisotope suitable for biomedical applications, have also been performed with high efficiency, thus demonstrating a proof of concept of such systems.

  

• IPEN-DOC 25427

  POVEDA, P.N.S. ; MOLARI, J.A.; BRUNELLI, D.D.; SILVA, L.A. . Caracterização estrutural e mecânica de polipropileno aditivado com diferentes auxiliares de processo. In: CONGRESSO BRASILEIRO DE ENGENHARIA E CIÊNCIA DOS MATERIAIS, 23., 04-08 de novembro, 2018, Foz do Iguaçu, PR. Resumo... 2018. p. 8768-8768.

  Abstract: O polipropileno é amplamente consumido na indústria do segmento plástico e utilizado em diversos processos de transformação devido ao conjunto de propriedades que apresenta e suas características de processabilidade. Os aditivos auxiliares de processo atuam nos materiais plásticos promovendo um melhor deslizamento entre as cadeias (lubrificantes) e/ou contribuindo na nucleação e cristalinidade (nucleantes). Para este estudo foram utilizados 3 tipos de aditivos auxiliares de processo: óxido metálico (nucleante inorgânico), sal metálico (nucleante orgânico) e lubrificante, aplicados em polipropileno copolímero a 0,5%, em massa. Com o objetivo de promover a mistura adequada dos aditivos na base polimérica, foram desenvolvidos concentrados (masterbatches), os quais foram aplicados diretamente ao polipropileno base no funil da injetora para confecção dos corpos de prova. Para análise das amostras de polipropileno aditivado e não aditivado (padrão), foram utilizadas as técnicas de Calorimetria Exploratória Diferencial (DSC) para verificação do grau de cristalinidade; Espectroscopia de Absorção no Infravermelho com Transformada de Fourier (FT-IR) para estudo das características estruturais; e resistência ao impacto Charpy para avaliar o efeito da aplicação destes aditivos nas propriedades mecânicas do polímero. De acordo com os resultados apresentados, as amostras B (lubrificante) e D (óxido metálico) apresentaram desempenho diferenciado quando comparadas à amostra padrão A (polipropileno copolímero). A amostra B (lubrificante), mostrou-se uma alternativa interessante para a facilitação de processamento do polímero estudado devido à promoção de fluxo maior, sem apresentar perdas nas propriedades mecânicas avaliadas.

  

• IPEN-DOC 25426

  MATOS, B.R. ; REY, J.F.Q.; MERINO, D.H.; SILVA, J.S. da ; SCHADE, U.; PUSKAR, L.; FONSECA, F.C. . The relation between the alpha/beta relaxation dynamics and the shape of ionomer building blocks. In: CONGRESSO BRASILEIRO DE ENGENHARIA E CIÊNCIA DOS MATERIAIS, 23., 04-08 de novembro, 2018, Foz do Iguaçu, PR. Resumo... 2018. p. 8629-8629.

  Abstract: The relation between the alpha/beta relaxations and the shape of the building blocks of ionomer materials is a key factor for programming an important temperaturedependent property: the memory of shape [1,2,3]. However, the morphology of ionomers is indirectly obtained via modeling of small angle X-ray scattering (SAXS) data owing to the hardly accessible image characterization of the nanometric building blocks - micelle-like cylindrical polymeric aggregates (radius ~ 2 - 6 nm and length > 100 nm) [3]. Herein, broadband dielectric spectroscopy (BDS) measurements, free from electrode polarization effects, allowed identifying the time and temperature dependence of the polarization of different length scales of the ionomer matrix, and more importantly, by directly providing the aspect ratio of the radius and length of the polymeric aggregates for each desired temperature. This finding is essential for controlling the shape of ionomer based functional products under several stimuli conditions, thereby advancing remarkable applications, such as four dimensional (4D) printing and polymer electrolyte fuel cells.

  

• IPEN-DOC 25425

  SILVA, J.S. da ; MATOS, B.R. ; SCHADE, U.; PUSKAR, L.; FONSECA, F.C. . Electrostatic interactions of Ionomer Films as Probed by Variable Temperature Synchrotron Infrared Spectroscopy. In: CONGRESSO BRASILEIRO DE ENGENHARIA E CIÊNCIA DOS MATERIAIS, 23., 04-08 de novembro, 2018, Foz do Iguaçu, PR. Resumo... 2018. p. 8626-8626.

  Abstract: The state of the art polymer electrolyte of Proton Exchange Membrane Fuel Cells (PEM), Nafion®, has poor mechanical and electrical properties at T > 100 °C. Specifically, long-term operation leads to irreversible performance losses that are related to an irreversible modification of the ionomer morphology above the temperature of alpha-transition (Talpha ~ 110 °C). Previous characterizations showed that the alpha-transition is dependent on the different states of covalent and ionic interactions among sulfonic acid groups, such as: ionic repulsions among RSO3-, dipolar attractions among RSO3H dipoles, hydrogen bonding of sulfonic groups with bulk and coordinated water molecules. The identification of both the functional groups interactions in the MIR bands and the “ion-hopping bands” in the FIR bands for annealed Nafion samples can give new insights into the role played by the ionic interactions on the alpha of ionomer membranes. Such approach for understanding the relationship between the dynamics of aplha-relaxation and Nafion morphology is missing in the literature, possibly due to the incipient number of FIR studies of Nafion. The central objective of this work is to advance the understanding of the chemical features involved during the aplha-transition of in situ annealed Nafion membranes with the high-resolution mid (MIR) and far (FIR) infrared spectroscopy using the IRIS beamline of BESSY II synchrotron light source. Herein, the effect of short-term annealing of Nafion at RH ~ 0% and selected temperatures below and above the alphatransition is presented. The comparison between SAXS and FTIR data of Nafion membranes annealed in situ revealed that the alpha-transition is due to the long range motion of the ionomer chains via weakening of electrostatic interactions of the ionomer functional groups.

  

• IPEN-DOC 25424

  ARAUJO, S.A. de; LANDINI, L. ; SALVADOR, V.L.R. ; SCAPIN, M.A. ; MASSANARES, B.F. ; URBANINHO, A.B. . Estudo da viabilidade de produção de biodiesel, a partir de óleos vegetais e catalisadores de resíduos de frutos do mar, em uma unidade reacional de hidrogenação em batelada, assistida por micro-ondas e aquecimento convencional. In: CONGRESSO BRASILEIRO DE ENGENHARIA E CIÊNCIA DOS MATERIAIS, 23., 04-08 de novembro, 2018, Foz do Iguaçu, PR. Resumo... 2018. p. 8358-8358.

  Abstract: Neste trabalho a proposta foi a realização de estudo da viabilidade da produção de biodiesel, partir de resíduos de óleos vegetais de atividades domésticas, empregando resíduos de conchas (CaCO3), preparados na forma de óxido de cálcio (CaO) como catalisadores, em uma unidade de reação em batelada, em escala de bancada, instalada no IPEN-CNEN/SP. Ela é capaz de operar com alta pressão de gás hidrogênio (até 200bar) e alta temperatura (até 500°C), utilizando micro-ondas (2.450MHz, com até 2kW contínuo e 8kW pulsado) e aquecimento convencional (elétrico). Nos testes, foram avaliadas as carga de óleo (mL); tipo e massa de catalisador, com ou sem pressão de gás hidrogênio (bar); temperatura (°C); tempo de reação (h); potência de micro-ondas (W); velocidade de agitação da carga (rpm); aquecimento convencional (MC). As determinações analíticas das amostras foram feitas por meio de densidade, cromatografia em fase gasosa (GC), titulação potenciométrica e fluorescência de raios-X. Foram levantados dados, a fim de compará-los com outras metodologias já utilizadas em literatura. A proposta deste trabalho foi analisar a eficiência do uso destes tipos de catalisadores e óleos, na produção de biodiesel, como uma tecnologia alternativa.

  

• IPEN-DOC 25423

  SARTORI, M.N. ; SILVA, L.G.A. ; CASTRO, D.P. . Reaproveitamento de aparas têxteis de poliamida 6 e poliamida 66 com elastano. In: CONGRESSO BRASILEIRO DE ENGENHARIA E CIÊNCIA DOS MATERIAIS, 23., 04-08 de novembro, 2018, Foz do Iguaçu, PR. Resumo... 2018. p. 8317-8317.

  Abstract: O Brasil é um dos principais produtores do setor têxtil no mundo, gerando milhões de empregos diretos e indiretos. Contudo, tal atividade cria diversos problemas ao meio ambiente como, por exemplo, a geração de resíduos sólidos proveniente dos processos industriais, confeccionistas e também do pós-consumo. Muitas vezes estes resíduos são descartados de modo displicente em aterros sanitários contribuindo para o depósito de resíduos no ambiente. Neste trabalho foram utilizadas aparas têxteis de poliamida 6 e poliamida 66 com elastano que são descartadas pela indústria. Esses materiais foram processados inicialmente em uma máquina compactadora para redução de volume. Posteriormente, pelo processo de extrusão foram obtidos grânulos e por injeção foram preparados os corpos de prova os quais foram submetidos aos ensaios mecânicos de tração, flexão e impacto. Os resultados encontrados revelaram que tanto as aparas de poliamida 6 como as aparas de poliamida 66 com elastano são processáveis e apresentaram características viáveis para utilização na indústria em diferentes segmentos.

  

• IPEN-DOC 25422

  CANAZZA, M.A.; WIEBECK, H.; SCAGLIUSI, S.R. . Novas aplicações do pó de pneu reciclado via microondas. In: CONGRESSO BRASILEIRO DE ENGENHARIA E CIÊNCIA DOS MATERIAIS, 23., 04-08 de novembro, 2018, Foz do Iguaçu, PR. Resumo... 2018. p. 8280-8280.

  Abstract: A reciclagem de materiais poliméricos tem sido objeto de estudos a fim de poupar recursos naturais, principalmente de fontes não renováveis, com objetivo de minimizar os impactos causados ao meio ambiente. Nesse cenário, aparecem os materiais elastoméricos, como a borracha, principalmente a utilizada na fabricação de pneus, uma vez que a indústria pneumática consome aproximadamente 60% da produção de borracha. Como a destinação final de forma ambientalmente correta do pneu é uma exigência, devidamente amparada por normas e leis nacionais e internacionais, o objetivo desse trabalho é desenvolver um estudo sobre a eficácia das irradiações das microondas no processo de desvulcanização do pó de pneu. Para esse estudo as amostras de pó de pneu foram submetidas a irradiações de microondas, e posteriormente incorporadas a matrizes poliméricas de Borracha Natural (NR) e Borracha de Butadieno Estireno (SBR), e caracterizadas por meio de ensaios para verificação de suas propriedades. Para caracterização das amostras, assim como a eficácia do processo, serão utilizados: (Ensaio de Dureza; Ensaio de Tração; Ensaio de Alongamento; (TGA), Análise Termogravimétrica; (DSC), Calorimetria Exploratória Diferencial). Verificou-se que dependendo da porcentagem de pó de pneu incorporado a matriz polimérica, a variação de propriedades é aumentada.

  

• IPEN-DOC 25421

  LIMA, V.S. ; PARRA, D.F. . Estudo das Propriedades e Estabilidade Térmica de Poli - metacrilato de metila luminescente dopado com complexo de Európio [Eu(tta)3(H2O)2] e complexo de Térbio [Tb(acac)3(H2O)3]. In: CONGRESSO BRASILEIRO DE ENGENHARIA E CIÊNCIA DOS MATERIAIS, 23., 04-08 de novembro, 2018, Foz do Iguaçu, PR. Resumo... 2018. p. 7858-7858.

  Abstract: Neste trabalho relatamos a preparação, caracterização térmica e luminescência das propriedades dos filmes poliméricos de polimetacrilato de metila luminescentes. Os filmes de PMMA foram dopados com complexo de európio sobre concentração de 0,5% e complexo de térbio sobre as concentrações de 1, 5 e 7%. Suas propriedades de luminescência e estabilidade térmica foram obtidas a partir de filmes obtidos por derramamento (casting). Os filmes foram caracterizados por TGA em atmosfera de N2, DSC e Espectro de emissão. Avaliação da estabilidade foto-física mostrou a influência da exposição do comprimento de onda UV no polímero. A calorimetria exploratória diferencial (DSC) não apresentou alterações significativas em Tm para as amostras de filmes expostos, no entanto, a cristalinidade é afetada por complexo nas cadeias poliméricas. Com base nos dados de TG comparou-se a estabilidade térmica entre as amostras de filmes dopados com as porcentagens informadas acima. Os espectros de emissão obtidos a 298K exibiram bandas características de 5D4 ? 7FJ (J=6, 5, 4, 3, 2, 1, 0). A intensidade de luminescência intensifica-se de acordo com a concentração dos íons de terra rara não indicando supressão de luminescência na faixa de concentração utilizada.

  

• IPEN-DOC 25420

  BENTO, R.T. ; FERRUS FILHO, A.; CORREA, O.V.; PILLIS, M.F. . Structural characterization of aramid fibers. In: CONGRESSO BRASILEIRO DE ENGENHARIA E CIÊNCIA DOS MATERIAIS, 23., 04-08 de novembro, 2018, Foz do Iguaçu, PR. Resumo... 2018. p. 7746-7746.

  Abstract: Fibers are polymer matrix composite materials that present one dimensional structure, stiffness, low density, and high structural and thermal properties. They can be used in activities under high temperature, being in the form of fabric and yarn. Aramid yarns are high performance textile fibers with excellent physicochemical properties that favor their use in applications where there is the requirement for advanced technology. The present research proposed the structural characterization of two different types of aramid yarn – 1100 dTex and 3300 dTex. X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), atomic force microscopy, thermogravimetric analysis (TGA), and difference thermogravimetry (DTG) were used for structural characterization, morphology analysis, chemical composition, and thermal degradation of samples. The results obtained demonstrated that the aramid fibers exhibit a crystalline structure, presenting a homogeneous surface morphology and low roughness. It was verified that the fibers in study have good thermal stability. The thermal decomposition of the 1100 dTex aramid occurs in the range of 493 °C – 629 °C, while the thermal degradation of the 3300 dTex aramid is initiated at approximately 504 °C and is completed around 644ºC, which allows to conclude that the 3300 dTex aramid is endowed with excellent thermal resistance when compared to other textile materials.

  

• IPEN-DOC 25419

  CASTRO, D.P. ; SARTORI, M.N. ; SILVA, L.G.A. . Efeito da radiação ionizante em blendas de pbat/amido plastificados com glicerol e óleo de mamona. In: CONGRESSO BRASILEIRO DE ENGENHARIA E CIÊNCIA DOS MATERIAIS, 23., 04-08 de novembro, 2018, Foz do Iguaçu, PR. Resumo... 2018. p. 7600-7600.

  Abstract: Diversas alternativas têm sido buscadas para minimizar o impacto ambiental causado pelos polímeros convencionais. Uma importante alternativa é o uso de polímeros biodegradáveis; no entanto, em razão do seu alto custo quando comparados com polímeros convencionais, surge a necessidade de desenvolver misturas poliméricas biodegradáveis utilizando aditivos naturais degradáveis, tal como o amido modificado. A utilização de polímeros biodegradáveis tem mostrado ser uma alternativa viável ao uso dos materiais derivados das poliolefinas, principalmente em embalagens, pelo fato de poderem ser compostados e biodegradados após o seu descarte. O desenvolvimento de blendas poliméricas fabricadas com matrizes de polímeros biodegradáveis sintéticos, e aditivos naturais, são considerados materiais menos agressivos ao meio ambiente; os quais podem ser degradados pela ação de microorganismos ou enzimas. Neste trabalho, foram preparadas blendas de amido termoplástico (TPS) com PBAT, glicerol, óleo de mamona e TWEEN® 80, as quais, foram preparadas por extrusão, e posteriormente submetidas ao processo de radiação e caracterizadas por análises térmicas, mecânicas e morfológicas. Os resultados mostraram uma boa interação entre os componentes das blendas e sua miscibilidade, tanto irradiadas quanto não irradiadas.

  

• IPEN-DOC 25418

  FARIAS, I.F. ; CASTRO, M.C.B. de ; MARINUCCI, G. . Estudo do reaproveitamento de resíduo de PVB utilizado na fabricação de parabrisas em composto de PVC. In: CONGRESSO BRASILEIRO DE ENGENHARIA E CIÊNCIA DOS MATERIAIS, 23., 04-08 de novembro, 2018, Foz do Iguaçu, PR. Resumo... 2018. p. 7500-7500.

  Abstract: A fabricação de blendas poliméricas é uma alternativa para melhoria de propriedades de materiais poliméricos já consolidados no mercado, ampliando sua área de aplicação como por exemplo, ABS/PC, PMMA/PET, PPO/HIPS, PBT/ABS e outros. O presente trabalho apresenta um estudo da compatibilização de dois polímeros termoplasticos e na avaliação das propriedades mecânicas. Os polímeros utilizados neste estudo foram: o composto de poli (cloreto de vinila)-PVC-C, aditivado com plastificantes, o poli (cloreto de vinila)reciclado-PVC-R, oriundo de mangueiras flexíveis e o resíduo de poli (vinil butiral)PVB-R, proveniente de laminados utilizados na fabricação de para-brisas para a indústria automotiva. O estudo das blendas PVC/PVB oferece um grande potencial de aplicação na fabricação de mangueiras e laminados, na indústria calçadista e automotiva e em segmentos da área hospitalar. Três diferentes formulações de blendas PVC/PVB foram planejadas e obtidas a partir de mistura no estado fundido via processo de extrusão por granulação a seco e processo de calandragem. As blendas de amostras de PVC plastificado e PVC reciclado, indicados respectivamente por PVC-C e PVC-R, e amostras de PVB do descarte na fabricação dos para-brisas indicadas por PVB-R foram fabricadas nas proporções de PVC-C/PVB-R 90/10, PVC-C/PVB-R 50/50 e PVC-R/PVB-R 50/50. Essas amostras foram comparadas com o composto de PVC-C puro, sendo atribuído como o material de referência, e com resíduo de PVB-R puro como material de incorporação. Foram realizados ensaios mecânicos e de dureza, como também a avaliação da miscibilidade da blenda. Após a análise, as blendas de PVC/PVB apresentaram interação em termos de compatibilidade e miscibilidade. Devido a polaridades semelhantes, o resíduo resultou numa grande vantagem competitiva de viabilidade econômica e de processos, econômica tendo em visto que o PVB resíduo apresenta custo inferior ao PVC composto e propriedades mecânicas superiores, isso porque a incorporação de resíduos de PVB normalmente implica num aumento das propriedades dessa blenda termoplástica. Essa conclusão é amparada pelos resultados de resistência à tração, resistência a dureza e rasgamento, como também das características morfológicas obtidas nas análises por microscopia óptica, que apontaram resultados satisfatórios comparados com composto de PVC plastificado.

  

• IPEN-DOC 25417

  FREITAS, P. ; YASUDA, F.S.; HEWER, T.L.R.; MELO, T.S.; DELORENZI, J.M.B.; SILVA, L.G.A. . Incorporação de nanopartículas de prata pelo processo de irradiação em cateter venoso central de poliuretano revestido com óxido de titânio para atividade antimicrobiana. In: CONGRESSO BRASILEIRO DE ENGENHARIA E CIÊNCIA DOS MATERIAIS, 23., 04-08 de novembro, 2018, Foz do Iguaçu, PR. Resumo... 2018. p. 7433-7433.

  Abstract: Os cateteres intravasculares são aliados indispensáveis na prática da medicina moderna, particularmente em unidades de terapia intensiva (UTIs). Pelo Cateter Venoso Central (CVC) pacientes que ficam muito tempo internados recebem medicação e alimentação sendo, no entanto, importante fonte de infecção da corrente sanguínea primária. Os CVC’s de poliuretano podem ter sua superfície modificada pela incorporação de titânio e prata (Ti/Ag) que são metais que possuem características antimicrobianas conhecidas desde a antiguidade. A incorporação das nanopartículas de prata sobre o polímero pode ser feita com o uso da radiação ionizante, que também irá esterilizar o material deixando-o disponível para uso final. Assim, este trabalho tem por objetivo utilizar a radiação ionizante para incorporação de nanopartículas de prata em Cateter Venoso Central (CVC) a fim de adquirir propriedades antibacterianas. Para isto utilizou-se o CVC Pellethane 2363-65D, termoplástico de poliuretano elastômero (TPU), óxido de titânio puro, sintetizado pelo processo sol gel e nanopartículas de prata (NpAg_925). A irradiação para incorporação da prata foi com dose de 25 kGy e com taxa de dose de 1,03 kGy/h em um irradiador “Gammacel 220” de Co-60. Posteriormente, os cateteres foram esterilizados com dose de 25 kGy. Observou-se que a deposição do titânio pelo método sol gel na superfície do CVC não foi homogênea, dificultando a incorporação da prata que depende do titânio neste processo de incorporação. A microscopia eletrônica de varredura mostrou falhas no processo de deposição do titânio, assim sendo os testes de atividade antibacteriana não tiveram resultados conclusivos. Podese concluir que a incorporação da prata pelo processo de irradiação foi possível e que este processo não afeta a estrutura do polímero, o que é importante para a correta inserção do cateter venoso central no corpo do paciente.

  

• IPEN-DOC 25416

  FAZOLIN, G.N. ; VARCA, G.H.C. ; LUGAO, A.B. . Desenvolvimento de nanocarreadores bioativos na forma sólida à base de papaína induzidas por radiação. In: CONGRESSO BRASILEIRO DE ENGENHARIA E CIÊNCIA DOS MATERIAIS, 23., 04-08 de novembro, 2018, Foz do Iguaçu, PR. Resumo... 2018. p. 7425-7425.

  Abstract: A papaína, enzima proteolítica extraída do látex do fruto verde do mamão papaia adulto, é um produto de interesse médico por possuir características importantes como auxiliar na redução do crescimento bacteriano em escaras além de possuir alta bioatividade e ser um produto com potencial para carreamento de fármacos. Recentemente desenvolvida em nano escala, a nanopartícula de papaína foi sintetizada utilizando a técnica de síntese por radiação a fim de promover reticulação intermolecular e esterilização do meio, simultaneamente. Contudo, a papaína em meio aquoso sofre hidrolise e por este motivo sua aplicação como nanocarreador pode ser dificultada. Visando a utilização da nanopartícula de papaína como nanocarreador de fármacos, se faz necessário a obtenção da nanopartícula na forma sólida. Este trabalho tem o objetivo de estudar o comportamento das nanopartículas de papaína congeladas e liofilizadas além de sua estabilidade frente ao tempo. A síntese foi realizada utilizando tampão fosfato 50 Mm pH 7,4 e etanol como cosolvente, além de induzir a reticulação com radiação ionizante utilizando a dose de 10 kGy e taxa de dose de 5 kGy.h-1. Após a síntese e irradiação, as amostras foram congeladas a - 80ºC. O tamanho e a estrutura secundária foram avaliados através das técnicas de espalhamento dinâmico de luz e fluorescência, a atividade enzimática foi analisada utilizando substrato específico. A amostra de papaína nativa possui tamanho médio de 4 nm e a nanopapaína ± 7 nm, contudo, após a liofilização, observou-se que os tamanhos não são mantidos, apresentando ± 4 nm para ambas as amostras. Os rendimentos das amostras foram superiores a 90% para todas as condições e considerados satisfatórios. Utilizando açúcares como trehalose e beta-ciclodextrina (2% v/v), este rendimento subiu para 96-98%, porém, a bioatividade caiu cerca de 30% após liofilização e 40% nas amostras liofilizadas com açúcar, ou seja, o dobro do esperado. Sendo assim, concluiu-se que o uso do açúcar é satisfatório no aumento do rendimento porem é indispensável na concentração estudada.

  

• IPEN-DOC 25415

  KOMATSU, L.G.H. ; OLIANI, W.L. ; RODELLA, E.F. ; LUGAO, A.B. ; PARRA, D.F. . Nanopartículas de Ag/TiO2 e Ag/CaCO3 aplicados em matrizes polímericas de HMSPP/SEBS visando atividade biocida. In: CONGRESSO BRASILEIRO DE ENGENHARIA E CIÊNCIA DOS MATERIAIS, 23., 04-08 de novembro, 2018, Foz do Iguaçu, PR. Resumo... 2018. p. 7400-7400.

  Abstract: As propriedades e a atividade biocida do compósito nanoestruturado de Polipropileno com Alta Resistência do Fundido (iPP) com o Elastômero Termoplástico estirenoetileno/ butadieno-estireno (SEBS), utilizando as nanopartículas de prata com dióxido de titânio (Ag/TiO2) e nanopartículas de prata com carbonato de cálcio (Ag/CaCo3) foram avaliadas por Espalhamento de Luz Dinâmico (DLS), Difração de Raios-X (DRX), Calorimetria Diferencial Expolratória (DSC), Espectroscopia de Raman, e ensaios biocidas. As nanopartículas de Ag/TiO2 e Ag/CaCO3 foram sintetizadas em laboratório, tendo como precursor metálico o nitrato de prata (AgNO3). Tanto os corpos de prova para os testes quanto o processamento dos compósitos, foram realizados em uma máquina inejetora de bancada. Investigou-se a formação de halo de inibição em ambos os materiais PP/SEBS/Ag/ TiO2 e PP/SEBS/Ag/CaCO3 frente a bactéria E. coli, afim de avaliar a dispersão e o tamanho da partícula que promova uma melhor interação com as celúlas das bactérias.

  

• IPEN-DOC 25414

  LIMA, C.S.A.; VARCA, J.O.; FERRARI, A.; NOGUEIRA, K.M.; VARCA, G.H.C. ; LUGAO, A.B. . Development of mucoadhesive PVA/CMC based hydrogel for intravesical chemotherapy. In: CONGRESSO BRASILEIRO DE ENGENHARIA E CIÊNCIA DOS MATERIAIS, 23., 04-08 de novembro, 2018, Foz do Iguaçu, PR. Resumo... 2018. p. 7343-7343.

  Abstract: Bladder cancer (BC) is one of the main diseases that attack the urinary tract and is globally responsible for 165,000 deaths per year. Bladder tumor may be classified as non-muscle invasive (superficial) or muscle invasive. About 70% of patients present the superficial bladder cancer which is treated by transurethral resection for tumor removal followed by intravesical chemo or immunotherapy. The main challenge reported in the instillation of chemotherapy is the limited drug residence time in the bladder as a consequence of urine levels that leads to fast drug removal from the bladder.1 Hydrogels are chemically or physically crosslinked polymer systems that form three-dimensional networks with high water absorption capacity. Carboxymethylcellulose (CMC) is one of the major soluble derivatives of cellulose widely applied in the medical and pharmaceutical fields due to its biocompatibility, nontoxicity, biodegradability and film forming ability.2 Polyvinyl Alcohol (PVA) is a synthetic polymer with wide pharmaceutical and biomedical applications as it is nontoxic, non-carcinogenic, bioadhesive and easy to process.3 In this work, we developed a mucoadhesive hydrogel from a CMC and PVA polymer blend for chemotherapeutic loading and suitable rheological properties for intravesical instillation, especially designed for treating superficial BC with increased residence time of chemotherapeutic agent. Three formulations (C1, C2 and C3) at different CMC concentrations were prepared - 1%, 2% and 3% (w/v), respectively. PVA concentration corresponded to 1% (w/v) for all formulations. The polymers were separately solubilized in Milli-Q water and then mixed prior to the addition of 20% (v/v) glycerin to increase the mucoadhesiveness of the material. The hydrogels were characterized according to their organoleptic and rheological properties to evaluate the behavior of the material under tension and temperature. Accelerated stability tests of the pharmaceutical form were also performed. Comparatively, formulations with glycerin presented improved mucoadhesiveness, and formulations with 1 and 2% of CMC presented more adequate rheological behavior for the proposed application. In conclusions, the systems presented adequate properties for the delivery of chemotherapeutic agents for optimized BC treatments.

  

• IPEN-DOC 25413

  SANTOS, T.M.R. ; SANTOS, M.J. ; CAMPOS, L.M.P. ; PARRA, D.F. . Avaliação das propriedades térmicas de compósitos experimentais odontológicos a base de BISGMA e TEGDMA utilizando como carga nanopartículas de MMT e MMT/AMX. In: CONGRESSO BRASILEIRO DE ENGENHARIA E CIÊNCIA DOS MATERIAIS, 23., 04-08 de novembro, 2018, Foz do Iguaçu, PR. Resumo... 2018. p. 7290-7290.

  Abstract: O objetivo do presente estudo foi identificar a influência da nanopartícula de Montmorillonita (MMT) carregada com amoxicilina (AMX) nas propriedades térmica de um compósito experimental odontológica a base de BISGMA e TEGDMA. Foram feitos ensaios individuais dos componentes da matriz polimérica odontológica, do compósito com de MMT e do compósito com MMT/Amoxicilina. Primeiramente foi feito um sol de MMT+AMX com 9 partes de MMT para 1 parte de AMX. Foram confeccionados compósitos com 9% de MMT e 10% de MMT/AMX e também um grupo controle sem carga para comparações. Observou-se a interação dos componentes da matriz odontológica entre si, da matriz carregada com o sol de MMT/AMX e da matriz utilizando somente a MMT como carga. As caracterizações dos compósitos foram realizadas por meio das seguintes técnicas: Análise de Termogravimetria (TGA), Calorimetria exploratória diferencial (DSC) e Espectroscopia de Infravermelho com transformada de Fourier (FTIR) dos compósitos. A faixa de temperatura na análise de TGA foi de 25 - 600 ºC com taxa de aquecimento de 10 ºC min-1, em atmosfera de nitrogênio. A faixa de temperatura do DSC foi de 25 - 550ºC, em atmosfera de nitrogênio e a análise de FTIR foi feita por transmitância dos compósitos e dos pós individualizados. Observaram-se por meio do TGA todos os eventos de decomposição dos componentes da matriz polimérica, os mesmos se degradaram abaixo de 500ºC. Já com todos os componentes devidamente homogeneizados. A temperatura de degradação total chegou a 510 ºC, já para o grupo com MMT e MMT/AMX em sua composição, a temperatura de degradação ultrapassou os 520 ºC. Foi observado que a MMT interfere na resistência térmica do compósito e a AMX não afetou a estabilidade que a MMT trouxe para o compósito. Por meio da análise de FTIR foi possível identificar a presença dos componentes, tanto para a matriz, quanto para as cargas.

  

• IPEN-DOC 25412

  NOGUEIRA, K.M.; VARCA, J.O.; VARCA, G.H.C. ; LIMA, C.S.A.; LUGAO, A.B. . Development of lignin-PVP based dressing for wound treatment. In: CONGRESSO BRASILEIRO DE ENGENHARIA E CIÊNCIA DOS MATERIAIS, 23., 04-08 de novembro, 2018, Foz do Iguaçu, PR. Resumo... 2018. p. 7289-7289.

  Abstract: Lignin is a carbon renewable source and has been widely explored in different fields in the last years, especially in biomaterials as dressing and other biomedical devices due its natural origin and low cost1. Poly(ethylene oxide) (PEO) is a synthetic polymer largely used in biomedical applications due its important characteristics such as high hydrophilicity, non-toxicity and ease of process2. The present work aimed to develop a lignin-PEO based dressing for wound treatment by casting. In specific terms, three different polymer blends were formulated using a range of 3 to 10% (w/v) lignin was tested with the addition of 1 to 3% PEO. Lignin was solubilized in aqueous solution (pH>13) alkalized with sodium hydroxide and PEO was solubilized in distilled water. The solutions were heated up to 70 ºC and homogenized until complete polymer dissolution. Then, PEO solution and poly(ethylene glycol) diacrylate (PEGDA) (0.5 - 1.0%) were added to the lignin solution and the blend was mixed for 30 minutes at 70 ºC. Posteriorly the blends were submitted to casting and drying under different conditions, room temperature for 48 hours and incubated at 40 ºC for 24 hours. A control sample of 6% lignin was prepared in the same conditions. Samples were evaluated by physico-chemical and morphological characterizations. The swelling and gel fraction profiles were assessed as well as thermal behavior by differential scanning calorimetry. Chemical modifications were evaluated by infrared spectroscopy. Samples with higher PEGDA content presented minor swelling index. The blends formulated presented different thermal behavior in comparison with the control. Infrared spectroscopy pointed some chemical modifications promoted by the crosslinking agent. In general terms, the material developed presented a potential to continue been explored as dressing for wound treatment

  

• IPEN-DOC 25411

  ANGELO, M.B.; MUCSI, C.S. ; ROSSI, J.L. ; ARANHA, L.C. ; BOTTREL, J.; MICELLI, A.L. ; ALENCAR, M.C. ; TAKEDA, E.; NIGRO, F. ; LEITE, D.M.C. . Caracterização morfológica de membrana polimérica em duas gramaturas distintas. In: CONGRESSO BRASILEIRO DE ENGENHARIA E CIÊNCIA DOS MATERIAIS, 23., 04-08 de novembro, 2018, Foz do Iguaçu, PR. Resumo... 2018. p. 7151-7151.

  Abstract: Regenerações ósseas maxilares, são procedimentos onde o cirurgião dentista reconstrói cirurgicamente uma falha óssea gerada por um trauma causado por um acidente, por cirurgias pregressas como extrações dentárias, pela perda óssea crônica devido a má higiene bucal durante a vida do paciente ou até mesmo por lesões que acometeram a estrutura óssea dessas regiões maxilares. Biomateriais sintéticos, cada vez mais são desenvolvidos para auxiliar nessas regenerações, evitando assim a utilização de materiais que apresentam maiores riscos e morbidades aos pacientes. Um exemplo de biomaterial que possui características interessantes é a membrana polimérica. A membrana atua como barreira seletiva, impedindo a migração de células epiteliais e tecido gengival, para a área contendo biomaterial. promovendo a manutenção do arcabouço ósseo, mantendo assim melhores condições para que possa ocorrer a formação de novo tecido ósseo e assim uma melhor reparação da área afetada. A membrana é composta de copolímeros de PLGA 85/15, (poli lactatoco- poli glicolato) um polímero biodegradável utilizado há anos na indústria médica, juntamente ao PLGA, a membrana contem também fosfatos de cálcio na forma de Hidróxiapatita e BTCP. Estes fosfatos são convertidos em novo tecido ósseo por células especializadas (osteoblastos), sendo absorvidos pelo corpo humano. Eles também auxiliam no processo de adesão celular por parte dos osteoblastos, gerando um ambiente mais favorável para o crescimento e formação de novo tecido ósseo. Visando a melhor indicação clínica da odontologia, principalmente na implantodontia auxiliando nas regenerações ósseas, o objetivo desse trabalho é a caracterização morfológica através do microscópio eletrônico de varredura (MEV) de uma membrana polimérica com 2 diferentes gramaturas, 500 micrometros e 700 micrometros respectivamente, em desenvolvimento por uma empresa nacional. A estrutura macro e micro foi analisada, notando-se a malha polimérica formada pelo PLGA e a presença dos grânulos de hidroxiapatita e BTCP em ambas amostras. Não foram observadas morfologicamente diferenças na rede polimérica do PLGA, nem nos grânulos de hidroxiapatita e BTCP adicionados ao polímero, nas amostras das duas gramaturas distintas. Apesar da caracterização morfológica através do microscópio eletrônico de varredura (MEV) ser de grande importância para o seguinte estudo, outros ensaios devem ser realizados para uma melhor caracterização do biomaterial, como hidrofilicidade, ensaio de tração, teste de degradação e área de superfície.

  

• IPEN-DOC 25410

  MORAIS, V.R.; LEME, D.R.; YAMAGATA, C. . Silicato de cálcio e magnésio dopado com terras raras para aplicação como material luminescente. In: CONGRESSO BRASILEIRO DE ENGENHARIA E CIÊNCIA DOS MATERIAIS, 23., 04-08 de novembro, 2018, Foz do Iguaçu, PR. Resumo... 2018. p. 1422-1422.

  Abstract: Nos últimos anos, silicatos de metais alcalinos dopados com terras raras têm sido fortemente pesquisados como uma nova geração de fósforos com persistência luminescente. Comparados com os sulfetos convencionalmente utilizados para esse fim, silicatos apresentam luminescência com maior brilho e duração, alem de maior estabilidade química e menor custo. No presente trabalho, fósforos à base de silicatos de cálcio e magnésio (CaxMgSi2O5+x), dopados com Dy3+ foram preparados pela combinação dos métodos sol-gel e coprecipitação. Géis de silica foram obtidos a partir de solução de silicato de sódio. Hidróxidos de Ca, Mg and Dy, precipitados a partir de soluções clorídricas com NaOH, foram adicionados ao gel de sílica. Após lavagem com água destilada para remoção de ions Cl-, o produto foi seco em estufa e calcinado a 1000°C por 2 horas. Os resultados de DRX confirmaram, após a calcinação, a formação da fase diopsita (CaMgSi2O6), fase adequada como host para material luminescente. No espectro de emissão observaram-se picos em 479, 496, 577 e 593 nm, que correspondem, respectivamente, as transições 4F9/2-6H15/2 e 4F9/2-6H13/2 do íon Dy3+. A morfologia do pó foi observada por MEV.

  

• IPEN-DOC 25407

  FILHO, J.C.S. ; SILVA, S.C. ; SOARES, E.P. ; VENANCIO, E.C.; ANTUNES, R.A.; TAKIISHI, H. . Caracterização e Tratamento Térmico do Óxido de grafeno para obtenção do Óxido de Grafeno reduzido. In: CONGRESSO BRASILEIRO DE ENGENHARIA E CIÊNCIA DOS MATERIAIS, 23., 04-08 de novembro, 2018, Foz do Iguaçu, PR. Resumo... 2018. p. 1211-1211.

  Abstract: Um dos grandes desafios para produzir o óxido de grafeno reduzido (rGO) é desenvolver rotas de obtenção que sejam viáveis economicamente e que apresentem um alto rendimento e qualidade estrutural. Neste trabalho, foi obtido o rGO por redução térmica do óxido de grafeno (GO) que foi sintetizado pelo método de Hummers modificado. As técnicas utilizadas para caracterização do GO e rGO foram por difração de raios X (DRX) e análise termogravimétrica (TGA). O DRX do GO exibiu apenas o pico característico em 2 teta =10°, correspondente ao conjunto de planos (002) e o termograma obtido por TGA determinou a melhor temperatura para a redução do GO. A perda de massa tem início próximo a 100°C, pela evaporação de voláteis e moléculas de água adsorvida nas camadas de GO e entre 150 e 230°C devido à remoção de grupos funcionais contendo oxigênio tais como (-OH), Epóxi e COOH. Entretanto, a maior perda de massa foi observada a 200°C, onde são obtidos o CO, o CO2 e vapor de água como subprodutos do processo de redução. Assim, observou-se que a temperatura e tempo de tratamento alteram o padrão das curvas das análises termogravimétricas sendo necessário, portanto seu controle. A redução térmica do GO, neste trabalho, foi realizada em atmosfera de nitrogênio, nas temperaturas de 200, 180 e 150°C e tempos de 30, 20 e 15 min, respectivamente. A análise das amostras obtidas por DRX, mostrou um deslocamento do pico 2 teta para 26° e a distância entre os planos atômicos d = 3,8 ?, referindo-se que houve a redução do GO em rGO. O rendimento (massa inicial GO – massa final rGO) das amostras obtidas foi superior a 50% em todos os experimentos, independente da temperatura e tempo utilizados, mostrando a viabilidade na obtenção do rGO no processamento pela redução térmica do GO.

  

• IPEN-DOC 25406

  GALEGO, E. ; SERNA, M.M. ; SILVA, P.M. ; BIGIO, J.C. ; FARIA, R.N. . Estudo de adsorção de Eosin Y por eletroforese em ZnO nanoestruturado. In: CONGRESSO BRASILEIRO DE ENGENHARIA E CIÊNCIA DOS MATERIAIS, 23., 04-08 de novembro, 2018, Foz do Iguaçu, PR. Resumo... 2018. p. 1118-1118.

  Abstract: Uma das etapas que requer maior tempo para produção de células sensibilizadas por corante é a adsorção do corante na nanoestrutura de ZnO impactando diretamente no custo de sua fabricação. Portanto, a minimização deste tempo sem perda da eficiência da célula é de vital importância para a implementação da fabricação em escala comercial. Este trabalho objetivou estudar a viabilidade do emprego da técnica de eletroforese para otimizar o tempo de adsorção do corante Eosin Y ou 2?,4?,5?,7?- Tetrabromofluorescein (C20H8Br4O5) no ZnO nanoestruturado crescido sobre lamina de vidro com superfície condutora (SnO) pelas técnicas SILAR (Successive Ionic Layer Adsorption and Reaction ) e CBD (Chemical Bath Deposition) . O corante Eosin Y foi dissolvido em água e etanol, soluções estas que apresentam o comportamento de um coloide onde a molécula de Eosin Y é carregada negativamente quando em água e positivamente quando em etanol. Na eletroforese foram estudados os parâmetros: concentração da solução, densidade de corrente e o tempo de eletroforese. Na célula da eletroforese utilizou-se como contra eletrodo uma chapa de alumínio. A quantidade de corante adsorvido foi avaliada por espectrometria UV/Visível (Cary 5000) após a dessorção em solução de NaOH. A utilização da água como solvente limitou a tensão para valores inferiores a tensão de eletrólise da água, uma vez que para tensões acima deste valor foi observada a geração de bolhas no catodo o que causou a esfoliação da nanoestrutura de ZnO. Com o aumento da concentração do corante observou-se um decréscimo da tensão indicando que a água ainda pode ser empregada como um solvente eficaz. Não foi observada a formação de bolhas com a utilização de etanol como solvente, porém a tensão foi maior empregando-se a mesma densidade de corrente nos dois solvente. A quantidade de corante adsorvida foi da ordem de 10-8 M/cm2 com duração de 15 minutos, valor compatível com a adsorção obtida utilizando o método tradicional da imersão de 4 horas. Observou-se que condições ótimas de concentração do corante na solução, densidade de corrente e tempo para adsorção do corante Eosin Y dependeu do solvente. Conclui-se que a eletroforese mostrou ser um método eficaz para a adsorção do corante reduzindo o tempo desta etapa em um dezesseis avos (1/16).

  

• IPEN-DOC 25404

  MUCCILLO, E.N.S. ; REIS, S.L. ; BATISTA, R.M. ; MUCCILLO, R. . Análise por dilatometria do processo de sinterização do condutor iônico La0,9Sr0,1Ga0,8Mg0,2O3-d. In: CONGRESSO BRASILEIRO DE ENGENHARIA E CIÊNCIA DOS MATERIAIS, 23., 04-08 de novembro, 2018, Foz do Iguaçu, PR. Resumo... 2018. p. 665-665.

  Abstract: Compostos cerâmicos com estrutura perovskita à base de LaGaO3 contendo substituições parciais por Sr e Mg nos sítios A e B, respectivamente, apresentam elevada condutividade de íons oxigênio e são candidatos como eletrólitos sólidos em células a combustível de óxido sólido. A sinterização destes condutores iônicos é, em geral, realizada em altas temperaturas, resultando em perda de Ga e conseqüente formação de fases não-condutoras. Neste trabalho o processo de sinterização do composto La0,9Sr0,1Ga0,8Mg0,2O3-d foi investigado pelos métodos da taxa constante de aquecimento e pela construção da curva mestra de sinterização, empregando dados de dilatometria. O principal objetivo foi avaliar a evolução da sinterização desta cerâmica preparada por reação em estado sólido, em tratamentos térmicos arbitrários. A análise dos dados de dilatometria permitiu obter a energia aparente de ativação (~865 kJ/mol), além de prever a evolução da densidade durante a sinterização não-isotérmica por meio da construção da curva mestra.

  

• IPEN-DOC 25403

  SILVA, D.V. ; GALDINO, G.S. ; BARBOSA, L.P.; CASINI, J.S.; FARIA, R.N. . Influence o separator thickness on the performance of electric double layer supercapacitors in aqueous electrolyte. In: CONGRESSO BRASILEIRO DE ENGENHARIA E CIÊNCIA DOS MATERIAIS, 23., 04-08 de novembro, 2018, Foz do Iguaçu, PR. Resumo... 2018. p. 664-664.

  Abstract: The effects of the separator thickness (?) upon the equivalent series and resistances (ESR) and specific capacitances (Cs) of supercapacitors electrodes have been investigated using commercially available porous filter paper (?=150 ?m, pores size=7.5 ?m, 80 gm-2). Commercial activated carbon electrodes immersed in 1molL- 1 KOH electrolyte (25oC) have been employed in this study. The specific capacitances were calculated from cyclic voltammetry curves at room temperature employing various scan rates (5, 10, 15 and 30 mVs-1). Internal series resistances of the supercapacitors were measured using the galvanostatic charge discharge curves also at room temperature. A maximum of 28 separators (?=4200 ?m) have been employed in this investigation. It has been shown that the ESR increases substantially with separator thickness (from 3.1 to 7.9 ?cm2). The specific capacitance decreased somewhat with increasing separator thickness and scan rates (from 64 to 52 Fg-1; at 5 mVs-1). The microstructures of the electrode material have been investigated using scanning electron microscopy (SEM) and chemical microanalyses employing energy dispersive X-ray analysis (EDX). A compositional and morphological evaluation of these electrodes showed a very homogeneous microstructure.

  

• IPEN-DOC 25402

  SERNA, M.M. ; GALEGO, E. ; SILVA, P.M. ; TATEI, T.Y. ; FARIA, R.N. . Estudo de supercapacitores para emprego em células solares sensibilizadas por corante. In: CONGRESSO BRASILEIRO DE ENGENHARIA E CIÊNCIA DOS MATERIAIS, 23., 04-08 de novembro, 2018, Foz do Iguaçu, PR. Resumo... 2018. p. 662-662.

  Abstract: Um dos problemas da geração de energia por células fotovoltaicas é o armazenamento para uso posterior. Neste sentido os supercapacitores se apresentam como uma solução viável ao problema. Estudos recentes mostram que o zinco é um candidato natural devido a sua alta densidade de energia que é da ordem de 650 A/g. As configurações utilizando supercapacitores planares ou em camada diretamente acoplados à célula solar sensibilizada por corante mostrou-se um caminho promissor de pesquisa. O objetivo deste trabalho foi o estudo de supercapacitores de ZnO e ZnO/carvão ativado para armazenamento de energia gerada por células solares sensibilizadas por corante. Os métodos SILAR (Successive Ionic Layer Adsorption and Reaction), CBD (Chemical Bath Deposition) e hidrotermal foram utilizados para a obtenção de eletrodos nanoestruturados de ZnO planares e em camadas, respectivamente, usando como complexantes: ácido etileno diamíno tetra-acético (EDTA) , hexametiltetramina (HMT) e uréia. Para os capacitores planares as nanoestruturas obtidas foram impregnadas com MnO2, enquanto que para os tradicionais o eletrodo consistiu de uma mistura na razão de X:Y de ZnO/Carvão ativado, com X e Y em proporção (%) de massa de 10:90, 20:80 e 30:70. A voltametria cíclica foi o método empregado para a avaliação da performance dos eletrodos usando como eletrólito o NaSO4 a 1M. Os voltamogramas dos eletrodos produzidos por SILAR/CBD sem impregnação de ZnO mostrou que o ZnO não pode ser considerado como um material apto para uso em supercapacitores. Com a adsorção de óxidos como o MnO2 ao ZnO nanoestruturado crescido no eletrodo leva a ocorrência de reações redox responsáveis pela pseudo-capacitância, processo pelo qual a energia é armazenada. O processo hidrotermal produziu partículas com aspecto semelhante ao SILAR/CBD para todos os complexantes estudados. A razão ZnO/carvão ativado que apresentou melhores resultados foi na proporção de 30:70. No caso dos eletrodos produzidos por SILAR/CBD o melhor resultado foi obtido utilizando o HMT como complexante, o qual produziu um filme de nanorods com menor orientação e quantidade de ZnO. Portanto, a utilização de ZnO para produção de pseudo-capacitores a serem empregados em células solares sensibilizadas por corante mostrou-se como uma opção viável de baixo custo.

  

• IPEN-DOC 25401

  CRUZ, P.D. ; COSENTINO, I.C. ; GALEGO, E. ; YOSHIKAWA, D. ; FARIA, R.N. . The effect of vacuum annealing and HDDR processing on the electrochemical characteristics of activated carbon and graphene oxide for the production of supercapacitors electrodes. In: CONGRESSO BRASILEIRO DE ENGENHARIA E CIÊNCIA DOS MATERIAIS, 23., 04-08 de novembro, 2018, Foz do Iguaçu, PR. Resumo... 2018. p. 660-660.

  Abstract: Electric double-layer capacitors or electrochemical supercapacitors prepared using activated carbons have been subjected to vacuum heat treatments at low and high temperatures (200, 400, 600, 800 and 1000°C). The activated carbon electrodes have been tested at a window potential of 1.1 V employing a KOH electrolyte (1.0 mol.L-1). The effect of thermal treatment (vacuum or HDDR) upon the electrical properties has been investigated by cyclic voltammetry and electrochemical impedance spectroscopy (EIS). It has been shown that the specific capacitance at 5 msV-1 increases from 50 Fg-1 to 130 Fg-1 after a heat treatment at 400°C for 1 hour under back pump vacuum. At this temperature the diminution in the specific capacitance with higher scanning rate (10 msV-1) was much less pronounced (from 130 Fg-1 to 109 Fg-1). Equivalent series resistance (ESR) and equivalent parallel resistance of supercapacitors electrodes have also been investigated. Internal resistances of the supercapacitors were calculated using the galvanostatic curves at several current densities (10-100 mAg-1). BET analysis of the starting carbon and after thermal treatments have also been carried out in this investigation. The activated structures have been studied using scanning electron macroscopy (SEM) and X-ray diffraction. A compositional and morphological evaluation of these electrodes showed no significant change on the activated carbon structure. Reduced graphene oxide electrodes have also been prepared in this investigation for a comparison.

  

• IPEN-DOC 25400

  FANTIN, L. ; YOSHIKAWA, D. ; GALEGO, E. ; FARIA, R.N. . Effects of electrolyte substitution on the specific capacitance and equivalent series resistance of energy storage electrochemical supercapacitors. In: CONGRESSO BRASILEIRO DE ENGENHARIA E CIÊNCIA DOS MATERIAIS, 23., 04-08 de novembro, 2018, Foz do Iguaçu, PR. Resumo... 2018. p. 657-657.

  Abstract: The microstructure, chemical composition, equivalent series resistance (ESR) and specific capacitance (Cs) of supercapacitors electrodes have been investigated. Commercial activated carbon electrodes employing organic electrolyte have been tested at a potential window of 1.1 and 2.7 V. Specific capacitances were calculated from cyclic voltammetry curves at room temperature employing various scan rates (2- 70 mV/s). Internal resistances of the supercapacitors were calculated using the galvanostatic cycling curves at several current densities (10-175 mA/g). A maximum specific capacity of 58 Fg-1 has been achieved with the organic electrolyte at a current density of 30 mA/g and a potential window of 2.7V. After this initial study, the organic electrolyte was removed from the electrodes by back pumping vacuum. Two new aqueous electrolytes have been substituted in the commercial electrodes for a comparison: Na2SO4 and KOH (1.0 mol/L). At a discharge density of 75 mA/g, the electrodes with KOH showed a maximum specific capacitance of 53 F/g whereas the Na2SO4 showed only 6 F/g. ESR of the electrodes with organic electrolyte and KOH were in the range of 20 ohms.cm^2 whereas with Na2SO4 of 14 ohms.cm^2. The microstructures of the electrode material have been investigated using scanning electron microscopy (SEM) and chemical microanalyses employing energy dispersive X-ray analysis (EDX). A compositional and morphological evaluation of these electrodes showed a very homogeneous structure.

  

• IPEN-DOC 25399

  FUJIMOTO, T.G. ; MUCCILLO, E.N.S. . Influência da zircônia estabilizada com ítria nas propriedades elétrica e microestrutura do galato de lantânio. In: CONGRESSO BRASILEIRO DE ENGENHARIA E CIÊNCIA DOS MATERIAIS, 23., 04-08 de novembro, 2018, Foz do Iguaçu, PR. Resumo... 2018. p. 653-653.

  Abstract: O galato de lantânio com substituições parciais de estrôncio e magnésio (LSGM) possui condutividade iônica superior aos condutores iônicos convencionais, como zircônia estabilizada com ítria (8YZS). Esta característica o torna de interesse tecnológico como eletrólito sólido em células a combustível de óxido sólido (SOFC), que operam em temperaturas intermediárias (500-700°C). Paralelamente ao desenvolvimento de novos eletrólitos sólidos para aplicação em SOFC, também se tem procurado meios de otimizar as propriedades dos materiais conhecidos. Com base nisso, neste trabalho foi investigada a influência de adições de 8YSZ nas propriedades elétricas e na microestrutura do LSGM. O aditivo foi introduzido nos teores de 1, 10 e 20% em massa pelo método de mistura de óxidos seguido de sinterização a 1450ºC. As principais técnicas de caracterização empregadas foram a determinação da densidade aparente de amostras sinterizadas pelo método hidrostático, identificação de fases por difração de raios X, análise microestrutural por microscopia eletrônica de varredura e caracterização elétrica por meio de medidas de espectroscopia de impedância. Os resultados obtidos mostraram que com o aumento do teor de aditivo as amostras atingiram densidade relativa ~99% para até 10% em massa de 8YSZ, porém aumentando o teor de aditivo para 20% esse valor diminui para ~92%. Os perfis de difração de raios X mostraram a fase predominante do LSGM. O tamanho médio de grãos aumentou conforme o aumento no teor de aditivo. O valor mais elevado de condutividade iônica foi obtido com adições de 1% em massa de 8YSZ.

  

• IPEN-DOC 25398

  REIS, S.L. ; MUCCILLO, E.N.S. . Condutividade iônica da céria com dupla dopagem contendo samária e disprósia. In: CONGRESSO BRASILEIRO DE ENGENHARIA E CIÊNCIA DOS MATERIAIS, 23., 04-08 de novembro, 2018, Foz do Iguaçu, PR. Resumo... 2018. p. 652-652.

  Abstract: Eletrólitos sólidos à base de céria contendo terras raras são considerados candidatos para aplicação em células a combustível de óxido sólido, devido sua alta condutividade iônica em temperaturas intermediárias (500-750°C) de operação. Esses materiais cerâmicos, principalmente a céria contendo gadolínia ou samária, exibem maior condutividade iônica em temperaturas relativamente mais baixas em comparação com eletrólitos sólidos de zircônia estabilizada com ítria. No entanto, algumas restrições relacionadas ao seu comportamento na sinterização, juntamente com a melhoria da condutividade iônica, ainda são objeto de investigação. Neste trabalho, a estratégia da dupla dopagem com os óxidos de samário e disprósio foi utilizada visando obter um eletrólito sólido cerâmico com condutividade iônica otimizada. A composição Ce0,8Sm0,2-xDyxO1,9 com x variando de 0 a 0,2 foi preparada por reação em estado sólido, e a influência do teor de disprósio na densificação e na condutividade iônica foi analisada por diversas técnicas. Todas as composições exibiram estrutura cúbica do tipo fluorita. Os eletrólitos sólidos sinterizados atingiram densidades superiores a 92% do valor teórico após sinterização a 1500°C/3 h e valor mais elevado de condutividade iônica do que a composição Ce0,8Sm0,2O1,9.

  

• IPEN-DOC 25394

  DALOIA, D.; NUNES, R.M.V.; SILVA, L.G.A. ; PARDINI, L.C.; LAKE, C.; GORGULHO, M.P.; EVORA, M.C.. Investigation of nanocomposites manufactured with carbon nanofiber functionalized via ionizing radiation. In: CONGRESSO BRASILEIRO DE ENGENHARIA E CIÊNCIA DOS MATERIAIS, 23., 04-08 de novembro, 2018, Foz do Iguaçu, PR. Resumo... 2018. p. 3722-3722.

  Abstract: In aerospace industry, Carbon nanofibers (CNFs) Pyrograf III have been investigated for the manufacture of nanocomposites. CNFs have excellent physical and chemical properties with low cost production however the functionalization of the surface is necessary to enhance the dispersion and tailor CNF to the host polymer. To this end, CNF surface was functionalized with acrylic acid (AA) via ionizing radiation process with objective to introduce functional groups on its surface, which may promote good interface between CNF and epoxy resin system. Nanocomposites were manufactured by two different methodologies of CNF dispersion in epoxy system. Three roll milling methodology promoted better dispersion due to the powerful shearing forces. Nanocmoposites manufactured with CNF functionalized with AA 20wt% solution via gamma irradiation presented better mechanical property as well as highest fiber matrix contact angle.

  

• IPEN-DOC 25393

  MOURA, E.A.B. ; BARTOLOMEI, S.S.; SANTANA, J.G. ; VALENZUELA-DIAZ, F.R.; WIEBECK, H.; GUVEN, O.. Preparação e caracterização de nanocompositos EVA/ARGILA/TiO2 para a aplicação no segmento de embalagens para alimentos. In: CONGRESSO BRASILEIRO DE ENGENHARIA E CIÊNCIA DOS MATERIAIS, 23., 04-08 de novembro, 2018, Foz do Iguaçu, PR. Resumo... 2018. p. 3719-3719.

  Abstract: O copolímero de etileno-acetato de vinila (EVA) é uma poliolefina que apresenta uma variedade de aplicações industriais, tais como cabos e fios, embalagens flexíveis, mangueiras e tubos, encapsulantes fotovoltaicos e calçados. O EVA é muito utilizado na fabricação de embalagens flexíveis para alimentos em razão das suas características de flexibilidade, tenacidade, elasticidade e transparência. O EVA vem sendo bastante utilizado para a obtenção de nanocompósitos, uma vez que o seu caráter polar pode facilitar as interações com as nanocargas adicionadas e conferir melhores propriedades mecânicas, térmicas e de barreiras a embalagem flexível processada a partir do nanocompósito quando comparadas as propriedades da embalagem de EVA puro. Neste trabalho filmes flexíveis de EVA reforçado com argila e dióxido de titânio foram preparados por extrusão, usando uma extrusora de duplarosca, seguida de extrusão plana em extrusora monorosca. Os efeitos da adição de argila e TiO2 nas propriedades dos filmes de EVA foram investigados por meio de ensaios mecânicos de tração, análises de DRX, DSC, TG, FE-SEM, TEM e UV-VIS e a correlação entre as propriedades foi discutida. Os resultados mostraram ganhos de propriedades mecânicas, térmicas e de barreira a UV do filme de EVA devido à adição de argila e dióxido de titânio. Estes resultados mostram que é possível obter ganhos de propriedades interessantes em filmes flexíveis de EVA para a aplicação em embalagens para alimentos pela adição de uma pequena quantidade de argila e de nanopartículas de dióxido de titânio.

  

• IPEN-DOC 25391

  FERREIRA, J.C. ; CAVALLARI, R.V. ; LIMA, N.B. ; RODRIGUES, T.S. ; BERGAMASCHI, V.S. ; SILVA, F.A. e . Synthesis and characterization of catalysts based on nickel, cerium, and lanthanum supported on biocarbon for ethanol steam reforming. In: CONGRESSO BRASILEIRO DE ENGENHARIA E CIÊNCIA DOS MATERIAIS, 23., 04-08 de novembro, 2018, Foz do Iguaçu, PR. Resumo... 2018. p. 3559-3559.

  Abstract: Ethanol steam reforming (ESR) is considered asa promising alternative for hydrogen production due to some differentadvantages that include the large availability, relatively low cost, andsuperior reactivity of ethanol as compared to other compounds. Thus, thistechnology is also considered more sustainable and greener as compared to othermethods usually employed for hydrogen production. However, the currentindustrial catalysts suffer from strong deactivation because the extensivecarbon deposition, which limits their performances and utilization. In order toovercome this limitation, we report herein the synthesis of a catalyst based onnickel, cerium and lanthanum supported on activated biocarbon by a microwaveassisted hydrothermal method. In this method, we first performed a hydrothermalactivation of the biocarbon support at 120 °C using nitric acid (0.3 M) in areactor coupled to a microwave source aiming the formation of acid groups atthe surface of our carbonaceous matrix. In a next step, the adsorption of La3+,Ce3+, and Ni3+ onto the activated biocarbon was performed by the addition ofLa(NO3)3.6H2O, Ce(NO3)3.6H2O, and Ni(NO3)3.6H2O in the suspension containingthe activated biocarbon and potassium thiosulfate for stabilization (pH 8.0) at75 °C. The obtained catalyst was then characterized by scanning electronmicroscopy, X-ray dispersive spectroscopy, X-ray diffraction, temperatureprogramed reduction, and surface area by the BET method. After this step, the catalystwas then evaluated towards the ESR, in which 100 % of ethanol conversion wasobserved with the formation of only H2 (~ 60%) and CO2 (ESR products) and COand CH4 as byproducts (both in low concentrations), indicating a goodselectivity for ESR. Good stability was also achieved with no significant lossof activity even after 24 hours of reaction at 550 °C. The reactants and thereaction products were analyzed by gas chromatograph (Agilent 7890A), equippedwith a thermal conductivity detector (TCD) and a flame ionization detector(FID) connected in series.

  

• IPEN-DOC 25389

  GALDINO, G.S. ; SILVA, D.V. ; CRUZ, P.D. ; CASINI, J.S.; SAKATA, S.K. ; FARIA, R.N. . Microstructural and electrochemical studies of HDDR-graphene supercapacitors electrodes in KOH electrolyte. In: CONGRESSO BRASILEIRO DE ENGENHARIA E CIÊNCIA DOS MATERIAIS, 23., 04-08 de novembro, 2018, Foz do Iguaçu, PR. Resumo... 2018. p. 2923-2923.

  Abstract: In the past, the hydrogenation disproportionation desorption and recombination (HDDR) process has only been used to produced rare earth transition metal polymer bonded permanent magnets with outstanding performance. Recently, however, it has been shown that the HDDR process (850oC) can be successfully employed to produce reduced graphene oxide for electrochemical supercapacitors. In the present work, the electrochemical characteristics of HDDR-graphene supercapacitors have been compared to those obtained with chemically reduced commercial graphene oxide. Lower HDDR processing temperatures (200-600oC) have been used in this study for a comparison with previous investigations. The equivalent series and parallel resistances (EPR and ESR) and specific capacitance (Cs) of HDDR-graphene supercapacitors electrodes have been investigated using cyclic voltammetry. Room temperature specific capacitances calculated from cyclic voltammetry curves at scan rates of 2 mVs-1 reached ~160 Fg-1 in 1 molL-1 KOH electrolyte. Internal series resistances of the HDDR-graphene electrodes were measured using the galvanostatic curves also at room temperature. The microstructures of the electrode material have been investigated using scanning electron microscopy (SEM) and chemical microanalyses employing energy dispersive X-ray analysis (EDX).

  

• IPEN-DOC 25388

  BENITEZ JARA, F.G. ; CRUZ, P.V. ; BARBOSA, L.P.; CASINI, J.C.S.; PERUZZI, A.J.; SAKATA, S.K. ; FARIA, R.N. . Low-temperature reduction of graphene oxide using the HDDR process for electrochemical supercapacitor applications. In: CONGRESSO BRASILEIRO DE ENGENHARIA E CIÊNCIA DOS MATERIAIS, 23., 04-08 de novembro, 2018, Foz do Iguaçu, PR. Resumo... 2018. p. 2922-2922.

  Abstract: In the present work, attempts of reducing a graphene oxide powder using a low temperature hydrogenation disproportionation desorption and recombination process (L-HDDR) has been carried out. A lower processing temperature in large scale production is significant as far as costs are concerned. Graphite oxide was prepared using a modified Hummers’ method and dispersed in ethanol, exfoliated using ultrasonication to produce Graphene Oxide (GO). Investigations have been carried out by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The experimental results of L-HDDR processing graphene oxide powder using unmixed hydrogen at 400°C and relatively low pressures (<2 bars) have been reported. X-ray diffraction patterns showed a reduction of graphene oxide with the L-HDDR process. The results showed that the L-HDDR process, as the standard HDDR process, can be applied to the reduction of graphene oxide to produce supercapacitor materials. The advantage of employing the L-HDDR process is a relatively a low temperature would reduce the cost of treatment that is a very important factor for producing large amount of material. Thus, the L-HDDR process has been considered a promising alternative method of reducing graphene oxide with efficiency and possibly in large scale production.

  

• IPEN-DOC 25387

  VIEIRA, L.S.; CASINI, J.C.S.; YOSHIKAWA, D. ; FARIA, R.N. ; MANSANI, G.L.. Influence of the electrolyte window potential on the electrical characteristics of supercapacitors operating elevated temperatures. In: CONGRESSO BRASILEIRO DE ENGENHARIA E CIÊNCIA DOS MATERIAIS, 23., 04-08 de novembro, 2018, Foz do Iguaçu, PR. Resumo... 2018. p. 2896-2896.

  Abstract: The equivalent series and parallel resistances (EPR and ESR) and specific capacitance (Cs) of supercapacitors carbon electrodes have been investigated using cyclic voltammetry and electrochemical impedance spectroscopy. Commercial activated carbon electrodes employing organic electrolyte have been tested using a window potential in the range of 2.7–3.8 V. Specific capacitances were calculated from cyclic voltammetry curves at room temperature employing various scan rates (2-50 mVs-1). Internal series resistances of the supercapacitors were measured using the galvanostatic curves at room temperature and above (25-100oC). The ESR increase to 9.75 ? at 25° and 2.7V for 110.5 ? at with operating temperature raise and also with overpotential. The parallel series resistance (EPR) have also been determined using self-discharge curves at 3, 24, 48 and 120h in three distinct temperatures (25-100oC). The EPR modify with increase of temperature and also with overpotential staring 0.623 M? at 25°C and 2.7 V for 0.089 M? at 100°C and 3.8V. The microstructures of the electrode material have been investigated using scanning electron microscopy (SEM) and chemical microanalyses employing energy dispersive X-ray analysis (EDX). A compositional and morphological evaluation of these electrodes showed a very homogeneous structure. It has been shown that the specific capacitance decreased considerably with scan rate, current density, electrochemical window potential and working temperature.

  

• IPEN-DOC 25386

  CIONE, F.C. ; ROSSI, J.L. ; SOUZA, A.C.. Study for the obtainment of the W-Cu-Ni system composite applying powder metalurgy for use as a radiation shielding material for gamma ray attenuation. In: CONGRESSO BRASILEIRO DE ENGENHARIA E CIÊNCIA DOS MATERIAIS, 23., 04-08 de novembro, 2018, Foz do Iguaçu, PR. Resumo... 2018. p. 2878-2878.

  Abstract: The metallic composite material of the tungsten-copper-nickel system (W-Cu-Ni) produced by powder metallurgy (P/M) presented has adequade characteristics to be an alternative material for gamma (?) radiation attenuation. Lead and depleted uranium are the materials commonly used for radiation atenuattion. They are materials with certain toxicity and aggressiveness to the environment. The W-Cu-Ni composites are non-toxic and do not present environmental risks. The tungsten, matrix metal of the composite, has as property its atomic density that is directly proportional to the electrons of its atoms important for the purpose of effects of radiation attenuation. For the preparation of the composite samples, the size of the metallic particles was determined and selected. In order to homogenize the metallic particle distribution and to reduce the average particle size, a ball mill was used for 12, 24 and 36 hours. After grinding, the particle size analysis presented the mean particle size of 12 ?m was observed. After the sintering step, in the micro-hardness tests an average of 303.3 HV was achieved for the composition W6Cu1Ni. To measure the absorption of radiation in the samples the classical scientific method of narrow beam geometry (NBG) experiments was employed. The gamma radiation source of cobalt-60 was selected to study the effects and adjustments on the values of the Half-Value Layer and (HLV) in the dimensions of the required shielding thickness. For unpublished composite sample W6Cu1Ni the HLV method indicated the necessity of 9.27 mm of thickness in the obtained density of 13.38 g.cm-3, superior to the density of lead (11,34 g.cm-3). As a comparative, database from the XCOM (NIST) were used and demostrating convergence between the simulated values of 9.15 mm and the experimental values obtained.

  

• IPEN-DOC 25385

  MUCSI, C.S. ; ROSSI, J.L. ; ALENCAR, M.C. ; REIS, L.A.M. ; ROSSI, A.C.. Uma discussão sobre a aeroelasticidade de quadricópteros não tripulados, drones, oferecendo subsídios para projetos. In: CONGRESSO BRASILEIRO DE ENGENHARIA E CIÊNCIA DOS MATERIAIS, 23., 04-08 de novembro, 2018, Foz do Iguaçu, PR. Resumo... 2018. p. 6986-6986.

  Abstract: Os veículos aéreos não tripulados vem ganhando grande notoriedade, face à ampla gama de suas aplicações científicas e tecnológicas. Estes apresentam construções tão simples como brinquedos até equipamentos com altíssimo valor técnico científico agregado, destinados à missões relevantes. O presente trabalho visa apresentar uma discussão sobre a aeroelasticidade destes equipamentos na escala métrica, assunto árido e escasso nesta nova aeronáutica. São apresentados resultados de simulações numéricas relacionando o comportamento dos componentes estruturais em função dos esforços mecânicos, mormente os relacionados à mudança de atitude do equipamento, rotações e inclinações. Os resultados obtidos indicam a necessidade de cuidado e atenção no projeto dos braços dos quadcópteros, com especial atenção às suas seções transversais e à raiz do braço, na junção com o corpo; para evitar instabilidades que de outra maneira sobrecarregariam o processador do estabilizador de vôo. Estes dados estão servindo de base para o projeto e construção de um equipamento voltado à detecção e localização de fontes radioativas.

  

• IPEN-DOC 25384

  FREITAS, L.F. de ; CAVALCANTE, A.K. ; LUGAO, A.B. . Radiolytic synthesis of non-toxic, size-homogeneous gold nanoparticles. In: CONGRESSO BRASILEIRO DE ENGENHARIA E CIÊNCIA DOS MATERIAIS, 23., 04-08 de novembro, 2018, Foz do Iguaçu, PR. Resumo... 2018. p. 6984-6984.

  Abstract: Radiolytic synthesis of nanoparticles is one of the successful examples of Green Chemistry (the use of non-toxic chemicals, environmentally benign solvents and renewable materials during the chemical processes), in which the reducing agents responsible for the particle nucleation are no other than the reactive species generated by the radiolysis of the solvent itself (i.e. water, acetone or alcohols). This study consists on the radiolytic synthesis and characterization of gold nanoparticles, as well as the assessment of their toxicity levels to Zebrafish embryos (Danio rerio), as an indication of a possible environmental effect. The nanoparticles were synthesized by mixing: NaAuCl4 2 x 10-3 M; polyvinylpyrrolidone 100 kDa 0.5% (as size stabilizer); propan-2-ol 0.2 M and acetone 0.06 M (for the generation of propyl radicals); and AgNO3 6 x 10-5 M (another size stabilizer), followed by 10 kGy of gamma radiation (5 kGy h-1) [1]. The particles were characterized by their absorption spectra in the UV and visible, and the dynamic light scattering (DLS) technique was used to assess their hydrodynamic size. Finally, the impact on the development of Zebrafish embryos was investigated for different dilutions of the nanoparticles suspension, according to the OECD protocol nº 236 (Guideline on Fish Embryo Acute Toxicity Test – FET), as a means of assessing the environmental impact of the nanomaterial. An acute (96 hours of exposition to gold nanoparticles) and a chronic (168 hours of exposition) assay were performed. The particles were successfully synthesized in a multipurpose gamma irradiator, with an absorption peak at 532 nm and a narrow size distribution (around 80 nm). There was no evident toxicity for the fish in any tested concentration, leading to the conclusion that this green method of nanoparticle synthesis generates a potentially environment-safe material, with good control of size and optical properties.

  

• IPEN-DOC 25383

  SOUZA, C.D. de ; CASTRO, A.; NOGUEIRA, B.R. ; FORTIN, M.; CHEVALLIER, P.; ROSTELATO, M.C.M. . Síntese de nanopartículas de ouro revestidas para uso em tratamento médico. In: CONGRESSO BRASILEIRO DE ENGENHARIA E CIÊNCIA DOS MATERIAIS, 23., 04-08 de novembro, 2018, Foz do Iguaçu, PR. Resumo... 2018. p. 6973-6973.

  Abstract: Nanopartícula são partículas em escala nanométrica e possuem propriedades únicas. Sua configuração promove alterações em seus comportamentos físicos, químicos e biológicos. As nanopartículas de ouro são estudadas há mais de 100 anos. Estados de oxidação comuns de ouro incluem Au+1, Au+3 e seu estado não oxidado Au0. O Au0 é o estado final desejável para nanopartículas. Assim, o passo principal envolvendo a síntese de AuNps é reduzir Au+1 ou Au+3 a Au0 adicionando e doador de elétrons (agente de redução) na reação. O precursor de escolha para a maioria das pesquisas é o ácido cloroáurico, HAuCl4 com ouro em seu estado de oxidação Au+3. Elas podem, por exemplo, transportar medicamentos para o interior das células sem perfurar as membranas celulares. Podem ajudar no tratamento do câncer através da liberação de medicamentos em partes específicas do corpo humano em intervalos controlados. Embora a síntese de nanopartículas de ouro seja amplamente relatada, na maioria dos casos a metodologia é confusa e/ou não clara. Além disso, a toxicidade dos reagentes deve ser levada em conta no desenvolvimento de produtos para aplicações médicas. Ácido cloroáurico- HAuCl4 (> 99,9% de traços metálicos), citrato de sódio- Na3Ctr (ACS ?99,0%) foram adquiridos da Sigma-Aldrich. Pellets de hidróxido de sódio- NaOH (ACS) foram adquiridos da J.T. Baker. Polietileno glicol- NH2-PEG-SH (5000 Mw) foram adquiridos da Laysan BIO. Todas as soluções foram feitas com água nanopura (Barnstead, 18,2 M?). 50 mL de 0,1 mM de HauCl4 contendo 100 ?L de NaOH a 1 M foram preparados em frasco de três bocas de 100 mL equipado com um condensador de refluxo. A solução foi aquecida em 80-90 °C enquanto era agitada com uma barra magnética revestida com PTFE. Em seguida, 5 mL de Na3Ctr 34 mM foram rapidamente adicionados. Análises de tamanho foram realizas por espalhamento de luz dinâmico DLS (Malvern). As reações de revestimento foram realizadas com polietilenoglicol (NH2-PEG-SH). O revestimento de PEG produziu partículas dentro do tamanho desejável (30-50 nm) com boa polidispersão e distribuição. O procedimento para o revestimento de PEG foi: Misturou-se 1 mL da solução de nanopartículas de ouro com 1 mL de 0,1 mM do agente de revestimento. A reação foi agitada num misturador de tubos eppendorf durante 2 horas. A caracterização foi realizada por FTIR- espectroscopia no infravermelho por transformada de Fourier (confirmando a presença do PEG na superfície), MET- Microscopia Eletrônica de Transmissão (confirmando o mesmo tamanho medido pelo DLS). DLS foi realizado durante o curso de 2,5 meses e confirma a estabilidade da reação.

  

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