Eventos - Resumos: Recent submissions

  • IPEN-DOC 24485

    COUTINHO, G.C.S. ; FALCAO, R.B. ; SILVA, R.A.; ROCHA, C.J. ; LEIVA, D.R.; ISHIKAWA, T.T.; BOTTA, W.J.; LEAL NETO, R.M. . MgH2-TiFe composite for hydrogen storage: synthesis and characterization. In: LATIN AMERICAN CONFERENCE ON METASTABLE AND NANOSTRUCTURED MATERIALS, 7th, March 19-22, 2017, Brotas, SP. Abstract... 2017.

    Abstract: MgH2 - 40wt.% TiFe composites were mechanical alloyed by high-energy ball milling, starting from both compounds, under high-purity argon atmosphere. In this case, the aim was to combine TiFe compound, which absorbs and desorbs hydrogen at or very near room temperature, with Mg, which has higher storage capacity. To avoid or reduce adherence on the vial and balls commercial MgH2 powder, instead of Mg, was used. TiFe was synthesized following a route described previously [1]. Three sets of experiments were done. In the first and second sets, MgH2 and TiFe powders were individually pre-milled in a shaker mill for 0.5 and 1 hour, respectively. Both milled powders were further mechanical alloyed in a planetary mill for 6 hours with ball-to-powder weight ratio (BPWR) of 40:1 (first set), or in a shaker mill for 2 hours, with BPWR of 30:1 (second set). In the third set, milling of both powders was conducted only in the shaker mill for 2 and 4 hours. Cyclohexane was used as process control agent in all experiments. DRX analysis showed no reaction between MgH2 and TiFe compound in all milled samples. Microstructural analysis by SEM revealed that TiFe particle size was 15% lower when pre-milling stage was performed (first and second sets of experiments). In the third set of experiments, TiFe particle size was reduced about 35% comparing milled samples for 2 and 4 hours (shaker mill). PCT and kinetics measurements were carried out in a Sieverts' type apparatus (under constant hydrogen flow) after heating the samples at 623K under vacuum for hydrogen desorption from MgH2. Results showed a increased hydrogen absorption capacity (about 4 wt % H2) for samples with lower TiFe particle size, which is accomplished after milling for 4 hours in the shaker mill.

    Como referenciar este item
    Icon

  • IPEN-DOC 24484

    CORREIA, C.S.C. ; GATTI, L.V. ; DOMINGUES, L.G. ; SANTOS, R.S. ; COSTA, W.R.; CRISPIM, S.P.; BORGES, V.F. ; MARANI, L.; GLOOR, E.U.; MILLER, J.B.. Long term nitrous oxide measurements over amazon basin using small aircraft. In: WMO/IAEA MEETING ON CARBON DIOXIDE, OTHER GREENHOUSE GASES, AND RELATED MEASUREMENT TECHNIQUES, 19th, August 27-31, 2017, Empa Dübendorf, Switzerland. Abstract... Geneva, Switzerland: World Meteorological Organization, 2017.

    Abstract: The Nitrous Oxide (N2O) is the third most important natural greenhouse gas on Earth (WMO, 2016). Globally, the main sources are nitrification and denitrification promoted by microorganisms and it can be natural (~60%) or anthropogenic (~40%) (IPCC, 2007). Approximately two thirds of soil emissions are provided from tropical areas and ~20% of this are from rainforests ecosystems as the region we have studied (Van Haren et al., 2005; Melillo et al. 2001). In Brazil 87% of N2O anthropogenic emissions are from agricultural activities. In this study, natural air was sampled in glass flasks using small aircraft over four sites in the brazilian Amazon Basin in order to have a great quadrant to better understand the whole area: Alta Floresta (ALF; 8.80ºS, 56.75ºW), Rio Branco (RBA; 9.38ºS, 67.62ºW), Santarém (SAN; 2.86ºS, 54.95ºW) and Tabatinga (TAB; 5.96ºS, 70.06ºW), ALF, RBA and TAB sites started in 2010 and we still perform sampling in these sites, the last one changed to Tefé (TEF; 3.39°S, 65.6°W) in 2013 due to technical problems. The measurements in SAN started in 2000 and the quantification was done by NOAA until 2003, after this year the analysis started to being done by our laboratory. The mixing ratios in all the studied stations have presented an increase along the years, varying from ~316ppm in 2000 in to ~330ppm in the present days, i.e. a mean growth rate of ~0.82ppm yr-1, which is consistent with global data where the growth rate for the past 10 years is around 0.89 ppm yr-1(WMO, 2016).

    Como referenciar este item
    Icon

  • IPEN-DOC 24487

    ROSSETTO, C.M.; MARTINEZ, L.G. ; ICHIKAWA, R.U. ; CAREZZATO, G.L. ; CARVALHO, A.M.G.; TURRILLAS, X.. Study of hydration of sulphoaluminate cement by in situ synchrotron diffraction. In: RAU ANNUAL USERS MEETING LNLS/CNPEM, November 22-24, 2017, Campinas, SP. Abstract... 2017. p. 135-135.

    Abstract: The hydration of calcium sulphoaluminate cement mixtures was studied in situ by synchrotron X-ray diffraction at the XRD1 beamline at the Laboratório Nacional de Luz Síncrotron (LNLS – Campinas). The specimens were analyzed in borosilicate glass capillary tubes of 0.7 mm and imbued with deionized water. As the hydration reaction is very fast, the data collection was started after two minutes of mixing with water. The Xray wavelength chosen to get an adequate flux for these short time acquisitions was 1.033258 Å (12 keV), determined with a corundum standard. Diffraction patterns were collected every 35 seconds at temperatures ranging from 40 °C to 55 °C with accuracy better than 0.1 °C attained with a hot air blower. The diffracted signal was collected with an array of 24 Mythen detectors [1]. The diffraction patterns accumulated had appropriate statistics to determine the kinetics of the reaction either by quantitative Rietveld analysis or by fitting isolated diffraction peaks to Gaussian curves as a function of time. The most important phases involved in the hydration are Klein´s salt, also known as Ye’elimite, Ca4(AlO2)6SO4, and gypsum, CaSO4.2H2O to yield Ettringite, Ca6Al2(SO4)3(OH)12·26H2O, phase responsible for the mechanical properties. These studies show the potential of XRD1 beamline to investigate at controlled temperatures in situ fast reactions involving crystalline phases with time resolutions inferior to one minute, which is ideal for the hydration of cementitious mixtures. The series of diffraction patterns collected for one and half hour are shown in Figure 1(a) and (b). In Figure 1(c) the evolution of the relative proportions of crystalline phases can be seen. Non-crystalline phases such as CSH gel or Al(OH)3 (gibbsite) are not taken in consideration [2]. The figures clearly show that the ettringite formation happens in two stages, the second one starting after approximately forty minutes. It is also interesting to notice that this stages seem to coincide with the depletion of Ca2SiO4 (C2S) for the first stage and the depletion of Ca3SiO5 (C3S) for the second one.

    Como referenciar este item
    Icon

  • IPEN-DOC 24483

    BARBOSA, HELLIOMAR P.; PEDROSO, CASSIO C.S.; SILVA, IVAN G.N.; FELINTO, MARIA C.F.C. ; MALTA, OSCAR L.; BRITO, HERMI F.. Multicolor emission in single-phase Ca(MoO4)(WO4):Dy3+, Eu3+ materials prepared by rapid synthesis. In: INTERNATIONAL CONFERENCE ON LUMINESCENCE, 18th, August 27 - September 01, 2017, João Pessoa, PB. Abstract... 2017. p. 393-393.

    Abstract: Solid state materials with dynamic emission colors form the basis of future smart lighting systems for a wide variety of everyday applications [1]. For this reason, the rare earth ions (RE3+) doping materials overtake the design of such systems exhibit easy tuning of colors and likewise offer straightforward spectral interpretations with their narrow lines characteristics. In this work we report preparation as well as the spectroscopic properties of the single phase new highly tricolor luminescent emitting of Eu3+, Dy3+ codoped into the Ca(MO4)(WO4) host lattice. The materials were prepared at room temperature exposed to ultrasonic irradiation for 30 min from stoichiometry aqueous solutions of Na2MoO4, Na2WO4, CaCl2, EuCl3 and DyCl3 (XDy: 0.3; XEu: 0.1 mol% of the Ca2+ amount). The as prepared materials were washed with distilled water, filtered and after dried. In the excitation spectrum, there is a broad band in the range 220-350 nm corresponding to the Ligandto- metal charge transfer (LMCT) (Fig.). This band can be deconvoluted into two bands. The band located at 270 nm is due only to the charge transfer O2-W6+, whereas that centered at 300 nm indicates energy transfer from O2-Mo6+, and O2-Eu3+. The emission arising mainly from the Dy3+ 4F9/26H15/2, 6H13/2 and Eu3+ 5D07F2, 7F4 transitions are due to the 488, 575, 614 and 700 nm, respectively (Fig.). In the 353 nm excitation wavelength the phosphor exhibits warm white color emission. These results suggest that Ca(MoO4)(WO4):Dy3+, Eu3+ could act as a multicolor phosphor in solid state-lighting technology.

    Como referenciar este item
    Icon

  • IPEN-DOC 24462

    CAMPOS, MAURICIO S.G.; SARKIS, JORGE E. de S. . New methodology for the analysis of volatile organic compounds (VOCs) in bioethanol by GC-MS. In: CONGRESSO BRASILEIRO DE METROLOGIA, 9.; CONGRESSO INTERNACIONAL DE METROLOGIA MECANICA, 4.; CONGRESSO INTERNACIONAL DE METROLOGIA ELETRICA, 12.; CONGRESSO BRASILEIRO DE METROLOGIA DAS RADIAÇOES IONIZANTES, 4.; WORKSHOP DA REDE DE METROLOGIA QUIMICA DO INMETRO, 3.; CONGRESSO BRASILEIRO DE METROLOGIA OPTICA, 2., 26-29 de novembro, 2017, Fortaleza, CE. Resumo... Rio de Janeiro, RJ: Sociedade Brasileira de Metrologia, 2017. p. 105-105.

    Como referenciar este item
    Icon

  • IPEN-DOC 24461

    CASTRO, MAYSA C. de ; SILVA, NATALIA F. da ; CALDAS, LINDA V.E. . Testing an extrapolation chamber in computed tomography standard beams. In: CONGRESSO BRASILEIRO DE METROLOGIA, 9.; CONGRESSO INTERNACIONAL DE METROLOGIA MECANICA, 4.; CONGRESSO INTERNACIONAL DE METROLOGIA ELETRICA, 12.; CONGRESSO BRASILEIRO DE METROLOGIA DAS RADIAÇOES IONIZANTES, 4.; WORKSHOP DA REDE DE METROLOGIA QUIMICA DO INMETRO, 3.; CONGRESSO BRASILEIRO DE METROLOGIA OPTICA, 2., 26-29 de novembro, 2017, Fortaleza, CE. Resumo... Rio de Janeiro, RJ: Sociedade Brasileira de Metrologia, 2017. p. 64-64.

    Palavras-Chave: x-ray sources; dosimetry; extrapolation chambers; computerized tomography; depth; leakage current; performance testing; standards; stabilization; brazilian cnen

    Como referenciar este item
    Icon

  • IPEN-DOC 24460

    FAUSTINO, MAINARA G. ; LANGE, CAMILA N. ; MONTEIRO, LUCILENA R. ; FURUSAWA, HELIO A. ; MARQUES, JOYCE R. ; STELLATO, THAMIRIS B. ; SOARES, SABRINA M.V.; SILVA, TATIANE B. de S.C. da ; SILVA, DOUGLAS B. da ; COTRIM, MARYCEL E.B. ; PIRES, MARIA A.F. . Top down Arsenic uncertainty measurement in water and sediments from Guarapiranga Dam (Brazil). In: CONGRESSO BRASILEIRO DE METROLOGIA, 9.; CONGRESSO INTERNACIONAL DE METROLOGIA MECANICA, 4.; CONGRESSO INTERNACIONAL DE METROLOGIA ELETRICA, 12.; CONGRESSO BRASILEIRO DE METROLOGIA DAS RADIAÇOES IONIZANTES, 4.; WORKSHOP DA REDE DE METROLOGIA QUIMICA DO INMETRO, 3.; CONGRESSO BRASILEIRO DE METROLOGIA OPTICA, 2., 26-29 de novembro, 2017, Fortaleza, CE. Resumo... Rio de Janeiro, RJ: Sociedade Brasileira de Metrologia, 2017. p. 117-117.

    Palavras-Chave: arsenic; water pollution monitors; sediments; dams; water reservoirs; sediment-water interfaces; quality control; measuring instruments; standards

    Como referenciar este item
    Icon

  • IPEN-DOC 24456

    SANTANA, LUCIANA V. de; COTRIM, MARYCEL E.B. ; SAID, DAPHNE de S.; ULRICH, JOAO C. ; PIRES, MARIA A.F. . Uncertainty estimation for the determination of uranium by titrimetric method Davies & Gray. In: CONGRESSO BRASILEIRO DE METROLOGIA, 9.; CONGRESSO INTERNACIONAL DE METROLOGIA MECANICA, 4.; CONGRESSO INTERNACIONAL DE METROLOGIA ELETRICA, 12.; CONGRESSO BRASILEIRO DE METROLOGIA DAS RADIAÇOES IONIZANTES, 4.; WORKSHOP DA REDE DE METROLOGIA QUIMICA DO INMETRO, 3.; CONGRESSO BRASILEIRO DE METROLOGIA OPTICA, 2., 26-29 de novembro, 2017, Fortaleza, CE. Resumo... Rio de Janeiro, RJ: Sociedade Brasileira de Metrologia, 2017. p. 102-102.

    Como referenciar este item
    Icon

  • IPEN-DOC 24493

    SHRIVASTAVA, NAVADEEP; KHAN, L.U.; VARGAS, J.M.; OSPINA, CARLOS; COAQUIRA, J.A.Q.; ZOPPELLARO, GIORGIO; BRITO, H.F.; FELINTO, M.C.F.C. ; SHARMA, S.K.. Photoluminescence and magnetic investigation of ternary ion activated enhanced multicolor LaF3 nanophasphores. In: INTERNATIONAL CONFERENCE ON LUMINESCENCE, 18th, August 27 - September 01, 2017, João Pessoa, PB. Abstract... 2017. p. 386-386.

    Abstract: The luminescence-tuneable multicolored LaF3:xCe3+,xGd3+,yEu3+ (x = 5; y = 1, 5, 10 and 15 mol%) nanoparticles have been synthesized via a new low cost polyol method. Powder X-ray diffraction and high resolution transmission electron microscopy confirms the hexagonal phase of LaF3:xCe3+,xGd3+,yEu3+ nanophosphors with average sizes (oval shape) from 5-7 nm. Energy-dispersive X-ray spectroscopy analyses show the uniform distribution of Ce3+, Gd3+ and Eu3+ dopants in the LaF3 host matrix. The photoluminescence spectra and electron paramagnetic resonance measurement guarantee the presence of Eu2+, corroborated through DC susceptibility measurements of the samples displaying the paramagnetic behavior at 300 K, whereas a weak ferromagnetic ordering at 2 K. The non-radiative energy transfer processes from the 4f1→4f5d1 state (Ce3+) (ultraviolet excitation, λex = 260 nm) to the intraconfigurational 4f excited levels of rare earth ions and simultaneous emissions in visible region from the 4f65d1 (Eu2+) and 5D0 (Eu3+) emitting level, leading to overlapped broad and narrow emission bands, have been proclaimed. The energy transfer mechanism proposes involvement of Gd3+ ion sub-lattice as bridge and finally trapping by Eu2+/3+, upon excitation of Ce3+ ion. The calculation of experimental intensity parameters (2,4) have been discussed and highest emission quantum efficiency (η = 85%) of Eu3+ ion for y = 10 mol% sample is reported. The advantageous existence of Eu2+/Eu3+ ratio along with variously-doped nanomaterials described in this work, exhibit tunable emission color in the blue-white-red regions, highlighting their potential application in solid state lighting devices, scintillation, and multiplex detection.

    Como referenciar este item
    Icon

  • IPEN-DOC 24490

    MOURA, J.L.; COSTA, I.F.; SANTOS, P.R.S.; TEOTONIO, E.E.S.; FAUSTINO, W.M.; BRITO, H.F.; FELINTO, M.C.F.C. ; BURROW, R.A.. Near infrared spectroscopic properties of new beta-diketonates lanthanide complexes with different phosphine oxide ligands. In: INTERNATIONAL CONFERENCE ON LUMINESCENCE, 18th, August 27 - September 01, 2017, João Pessoa, PB. Abstract... 2017.

    Abstract: The present work reports the synthesis, characterization and luminescent properties of the Ln3+--diketonate complexes, Ln(-dik)2(NO3)L2, Ln()3L2 and Ln(DBM)3L, where Ln3+ = Pr3+, Nd3+, Sm3+, Er3+ and Yb3+, -dik = thenoyltrifluoroacetone (TTA) and dibenzoylmethane (DBM), L = triphenylphosphine oxide (TPPO), tributylphosphine oxide (TBPO), and trioctylphosphine oxide (TOPO). The complexes were characterized by complexometric titration with EDTA, CHN elemental analysis, IR spectroscopy (FT-IR) and thermogravimetric analysis (TGA) [1]. Single-crystal X-ray diffraction analyses reveal that Ln(DBM)2(NO3)(TOPO)2 complexes crystallize in the monoclinic space group P21/c with parameters cell: a=36.727 Å; b=13.752 Å; c=15.836 Å; =90°; =93.09° e 90°. Photoluminescent properties in the near infrared (NIR) region were investigated from excitation and emission spectra. Excitation spectra are characterized by the presence of large bands associated with transitions centered on organic ligands, indicating that these ligands act as good sensitizers for Ln3+ ions that exhibit luminescence in the NIR region. The emission spectra in the NIR region of the bis- and tris-diketonate complexes of Pr3+, Nd3+, Sm3+, Er3+ and Yb3+ ions present the set of intraconfiguration transitions, characteristic of each metal center (Figure 1) [2]. Furthermore, it was observed that changes in the nature and number of ligands coordinated to the Ln3+ ion slightly influence the spectral profiles. The results obtained from the studied systems suggest that these are potential candidates to act as Molecular Light Converting Devices.

    Como referenciar este item
    Icon

  • IPEN-DOC 24489

    MIRANDA, Y.C.; SILVA, P.R.S.; TEOTONIO, E.E.S.; FAUSTINO, W.M.; BRITO, H.F.; SILVA, F.F.; MALTA, V.R.S.; FELINTO, M.C.F.C. . Novel dipivaloylmethanate compounds of trivalent lanthanide ions: synthesis, structure and energy transfer. In: INTERNATIONAL CONFERENCE ON LUMINESCENCE, 18th, August 27 - September 01, 2017, João Pessoa, PB. Abstract... 2017. p. 109-109.

    Abstract: This work reports on the synthesis, characterization and investigation of photoluminescence properties of novel [Ln(dpm)(NO3)2(thpo)2] complexes (where THPO : trihexylphosphine oxide and Ln : Tb, Gd or Eu). The compounds were characterized by elemental analysis of CHN, vibrational spectroscopy in the infrared region, thermogravimetric analysis and their spectroscopic properties were investigated by molecular diffuse reflectance, excitation and emission as well as decay times of emitting states. Single-crystal X-ray diffraction analyses reveal that [Ln(dpm)(NO3)2(thpo)2] complexes crystallize in the monoclinic space group P21/n with parameters cell: a =17.1926(2), b = 18.1226(2) c = 18.2508(2) Å; = 90°; = 108.908° e 90°. Interestingly, the phosphine oxide ligands are located in opposite positions, in contrast to that observed for similar complexes presenting dbm (dibenzoylmethanate) and hmpa (hexamethylphosphoramide) ligands (Figure 1). These results reflect differences in the luminescence properties of the Ln-mono(diketonate) complexes. The presence of metal ligand charge transfer state (TCLM) of low energy in the Eu3+ compounds was also investigated. According with the experimental data, ligand to metal charge transfer state (TCLM) for the [Eu(dpm)(NO3)2(thpo)2] system is located in higher energy than for dimeric complex of formula [Eu2(DPM)6].

    Como referenciar este item
    Icon

  • IPEN-DOC 24486

    FELINTO, MARIA C.F.C. ; BRITO, HERMI F.; TEOTONIO, ERCULES E.S.; MALTA, OSCAR L.. Rare earth nanomaterials for bio-application and theranostic. In: INTERNATIONAL CONFERENCE ON LUMINESCENCE, 18th, August 27 - September 01, 2017, João Pessoa, PB. Abstract... 2017. p. 436-436.

    Abstract: Luminescent materials, the so-called fluorophores, have been played a role in the diagnostic area over the years. In last decades, luminescent rare earth nanomaterials are receiving increasing attention due to its wide range of potential applications, including bioanalytical, images, dye-sensitized solar cells, nanobiotechnology and catalysis1-3. Other promising applications of luminescence materials include radiation detection, sensors for structural damage, optical memory media, identification markers, medical diagnostics, optical probes for in vivo bioimaging, molecular thermometers, etc1-4. The feature spectroscopic properties of rare earth ions such as high intense emission bands, high color purity, long lifetime and high emission quantum efficiency make them strong candidates for use as markers or bio- selective detectors. Besides, the interest in developing nanoparticles (NP) associated with biological materials continues growing rapidly1-4. This interest is mainly motivated by the desire to simultaneously exploit the optical properties of both the NP and biological components in new hybrid operating devices or luminescent materials that can be applied in strategic biomedicine areas. Nowadays researchers have given special attention to materials that display dual functions as marking the biological material by luminescent process and destroy malignant cells. This statement is based on the association of properties in the same material, as luminescence and magnetism or light associated to the capacity to interact with a drug and guide this drug to the targets. These materials are assigned theranostic materials, where it is a concept of “the ability to affect therapy or treatment of a disease state“, and the material play a role of marker and contributes in the therapy process. In this work, we present the luminescence study of various materials, synthesized and characterized in several laboratories that are part of the group of fluoroimmunoassays of inct-INAMI and NanoBio networks and are potential biophotonic materials to use as biomarkers. An attention to materials that emit in the regions of visible (Eu3+, Tb3+, Sm3+ and Dy3+) and near infrared (Nd3+ will be discussed.

    Como referenciar este item
    Icon

  • IPEN-DOC 24455

    NEVES, LUCIO P. ; SILVA, RAYRE J.V.; PERINI, ANA P.; SANTOS, WILLIAM de S.; VEDOVATO, ULY P.. Avaliação dosimétrica de procedimentos de tomossíntese mamária. In: CONGRESSO BRASILEIRO DE METROLOGIA, 9.; CONGRESSO INTERNACIONAL DE METROLOGIA MECANICA, 4.; CONGRESSO INTERNACIONAL DE METROLOGIA ELETRICA, 12.; CONGRESSO BRASILEIRO DE METROLOGIA DAS RADIAÇOES IONIZANTES, 4.; WORKSHOP DA REDE DE METROLOGIA QUIMICA DO INMETRO, 3.; CONGRESSO BRASILEIRO DE METROLOGIA OPTICA, 2., 26-29 de novembro, 2017, Fortaleza, CE. Resumo... Rio de Janeiro, RJ: Sociedade Brasileira de Metrologia, 2017. p. 53-54.

    Como referenciar este item
    Icon

  • IPEN-DOC 24454

    CALDAS, LINDA V.E. ; OLIVEIRA, LUCAS N. de; NASCIMENTO, ERIBERTO O. do; SCHIMIDT, FERNANDO; ANTONIO, PATRICIA L.. Assessment of ethylene vinyl-acetate copolymer samples exposed to gamma-rays via linearity analyses. In: CONGRESSO BRASILEIRO DE METROLOGIA, 9.; CONGRESSO INTERNACIONAL DE METROLOGIA MECANICA, 4.; CONGRESSO INTERNACIONAL DE METROLOGIA ELETRICA, 12.; CONGRESSO BRASILEIRO DE METROLOGIA DAS RADIAÇOES IONIZANTES, 4.; WORKSHOP DA REDE DE METROLOGIA QUIMICA DO INMETRO, 3.; CONGRESSO BRASILEIRO DE METROLOGIA OPTICA, 2., 26-29 de novembro, 2017, Fortaleza, CE. Resumo... Rio de Janeiro, RJ: Sociedade Brasileira de Metrologia, 2017. p. 52-53.

    Palavras-Chave: absorbed radiation doses; cobalt 60; copolymers; dosemeters; ethylene; fourier transformation; gamma radiation; infrared spectra; pva; vinyl acetate

    Como referenciar este item
    Icon

  • IPEN-DOC 24446

    BARBIERI, CRISTINA B.; SARKIS, JORGE E. de S. . A importância da metrologia na análise forense ambiental: aplicação do ensaio duplicado para estimativa de incerteza de amostragem. In: CONGRESSO BRASILEIRO DE METROLOGIA, 9.; CONGRESSO INTERNACIONAL DE METROLOGIA MECANICA, 4.; CONGRESSO INTERNACIONAL DE METROLOGIA ELETRICA, 12.; CONGRESSO BRASILEIRO DE METROLOGIA DAS RADIAÇOES IONIZANTES, 4.; WORKSHOP DA REDE DE METROLOGIA QUIMICA DO INMETRO, 3.; CONGRESSO BRASILEIRO DE METROLOGIA OPTICA, 2., 26-29 de novembro, 2017, Fortaleza, CE. Resumo... Rio de Janeiro, RJ: Sociedade Brasileira de Metrologia, 2017. p. 65-65.

    Palavras-Chave: environment; pollution; metrology; crime detection; data covariances; uncertainty principle; sampling

    Como referenciar este item
    Icon

  • IPEN-DOC 24255

    PERINI, ANA P.; MENDONÇA, DALILA S.C.; NEVES, LUCIO P.; SANTOS, WILLIAM de S.; BELINATO, WALMIR; CALDAS, LINDA V.E. . Uso do código de Monte Carlo MCNP para caracterização de uma câmara de ionização tipo lápis. In: CONGRESSO BRASILEIRO DE METROLOGIA, 9.; CONGRESSO INTERNACIONAL DE METROLOGIA MECANICA, 4.; CONGRESSO INTERNACIONAL DE METROLOGIA ELETRICA, 12.; CONGRESSO BRASILEIRO DE METROLOGIA DAS RADIAÇOES IONIZANTES, 4.; WORKSHOP DA REDE DE METROLOGIA QUIMICA DO INMETRO, 3.; CONGRESSO BRASILEIRO DE METROLOGIA OPTICA, 2., 26-29 de novembro, 2017, Fortaleza, CE. Resumo... Rio de Janeiro, RJ: Sociedade Brasileira de Metrologia, 2017. p. 65-65.

    Palavras-Chave: monte carlo method; ionization chambers; computerized simulation; dosimetry; dimensions; x radiation; configuration; pvc; brazilian cnen

    Como referenciar este item
    Icon

  • IPEN-DOC 24252

    VEGA, L.E.R.; LEIVA, D.R.; FIGUEROA, S.J.A.; SILVA, W.B.; LEAL NETO, R.M. ; ISHIKAWA, T.T.; BOTTA, W.J.. Hydrogen storage properties of TiFe prepared by cold rolling under inert atmosphere. In: LATIN AMERICAN CONFERENCE ON METASTABLE AND NANOSTRUCTURED MATERIALS, 7th, March 19-22, 2017, Brotas, SP. Abstract... 2017.

    Abstract: In this study, TiFe was prepared through the arc melting of Ti and Fe powders in the stoichiometric ratio 50:50, and then submitted to 20 and 40 cold rolling passes under inert atmosphere. The structural characterization of the samples revealed coarse grains after arc melting, formation of small cracked foils and the presence of powder, which was constituted of small particles agglomerated in the process of cold rolling. The local crystal structure was confirmed to be CsCl-type by EXAFS measurements on the initial compound after 20 CR at Fe and Ti K-edges which is expected for the stoichiometry. No absorption of hydrogen was observed in the sample processed by arc melting. On the other hand, the cold rolled material exhibited fast hydrogen absorption without using a thermal activation process. Regarding the hydrogen absorption capacities, around 1.4 wt. %. was achieved at room temperature and 20 bar of H2, for samples in the form of powder or foils. The process of cold rolling under inert atmosphere generated a product free of contamination by oxides, introducing simultaneously a high amount of defects in the material, which contributes for better hydrogen absorption kinetics.

    Como referenciar este item
    Icon

  • IPEN-DOC 24246

    CAMPELLO, F.A. ; IZIDORO, J.C. ; GHILHEN, S.N. ; FUNGARO, D.A. . Immobilization study of toxic elements present in coal ash through the treatment with immobilizing agents. In: INTERNATIONAL WORKSHOP ADVANCES IN CLEANER PRODUCTION, 10th, May 24-26, 2017, São Paulo, SP. Abstract... 2017.

    Abstract: The capacyity to immobilize toxic elements present in coal ashes using organosilane (OS) and surfactant (SF) as immobilizing agents was determined by batch experiments. The coal ashes used in the study was collected at the Figueira Thermal Power Plant, located in the city of Figueira, State of Paraná. Firstly, the influence of ash mass/water volume ratio on the concentration of the elements in the leachates was evaluated. Subsequently, the capacities of immobilization of toxic elements using the different immobilizing agentes, pH and conductivity of the leachates were determined. A significant reduction in the concentration of the elements was observed for all leachate samples obtained from the ashes treated with OS. Concentration reductions using OS were 89%, 77%, 42% and 11% for Cr, Mo, As and Se, respectively. When SF was used to the ashes treatment, the concentration reduction in the leachates was above 60% for all elements. These results show that both the organosilane and the surfactant can be used as immobilizing agents for the retention of toxic elements present in coal ashes.

    Como referenciar este item
    Icon

  • IPEN-DOC 24442

    SANTOS, R.S. ; GATTI, L.V. ; DOMINGUES, L.G. ; CORREIA, C.S.C. ; AQUINO, A.R. ; BASSO, L.S. ; BORGES, V.F. ; COSTA, W.R.; CRISPIM, S.P. ; MARANI, L.; GLOOR, E.U.; MILLER, J.B.; PETERS, W.. Amazon basin and brazilian coast SF6 study in a 15 years time series. In: WMO/IAEA MEETING ON CARBON DIOXIDE, OTHER GREENHOUSE GASES, AND RELATED MEASUREMENT TECHNIQUES, 19th, August 27-31, 2017, Empa Dübendorf, Switzerland. Abstract... Geneva, Switzerland: World Meteorological Organization, 2017. p. P55-P55.

    Abstract: The sulphur hexafluoride (SF6) is known as a potent Long Lived Greenhouse Gases and it is a synthetic gas with a millennia lifetime, about 3200 years, and has a Global Warm Potential 23000 time higher than the Carbon Dioxide (CO2). Levin et al. (2010)1 showed that SF6 emissions decreased after 1995, most likely because of emissions reductions in developed countries, but then increased after 1998. It is produced by the chemical industry, mainly as an electrical insulator in power distribution equipment2. Due its very long lifetime, SF6 emissions are accumulating in the atmosphere. Its global mole fraction increased nearly linearly in recent decades and in 2014 is about twice the level observed in the mid-1990s3. Its concentration was 4.2 parts per trillion (ppt) in 1998 (TAR) and has continued to increase linearly over the past decade, implying that emissions are approximately constant. Because of these characteristics, the SF6 has been as an essentially inert tracer to study atmospheric and oceanic transport processes3. The Amazon Basin is an ecosystem that has a growing interest by researchers around the world because of its role at the Climate Change. The emissions of SF6 in the Amazon Basin are considered non existents and, a time series of 15 years has the potential to show the behaviour of this gas in a large area. Until now, our mainly interest in SF6 concentrations is to use this gas as a transport tracer to calculate the BKG to Amazon and determinate the CO2, CH4 and N2O fluxes over the Amazon Basin. SF6 atmospheric measurements were started with vertical profiles using small aircrafts, since 2000 in Santarém (SAN; 2.86ºS; 54.95ºW), 2009 in Rio Branco (RBA; 9.38ºS, 67.62ºW), 2010 in Alta Floresta (ALF; 8.80ºS, 56.75ºW)and Tabatinga (TAB; 5.96ºS, 70.06ºW), all these sites located in Brazilian Amazon Basin. Since 2010, we started flasks measurements at two sites located at the Brazilian Atlantic coast: in Salinópolis (SAL; 0.60°S, 47.37°W) and in Natal (NAT; 5.48°S, 35.26°W) and later in 2014 at Camocim (CAM; 2.86°S, 40.08°W) and in 2016 at Itarema in a 100m tower (ITA; 2.93°S, 39.84°W). This work will present analyse of 15 years SF6 measurements at the Amazon Basin and Brazilian coast show the trends, comparing the years and the behaviour among the sites regions which is expect to change mainly by the differences of the air masses origin.

    Como referenciar este item
    Icon

  • IPEN-DOC 24434

    DOMINGUES, L.G. ; GATTI, L.V. ; GLOOR, M.; MILLER, J.; AQUINO, A.R. ; MARANI, L.; CORREA, C.S.C. ; BORGES, V.F. ; SANTOS, R.S. ; CRISPIM, S.P. ; SANCHES, A.; COSTA, W.R. da. Carbon monoxide measurements as a biomass burning tracer at the amazon basin. In: WMO/IAEA MEETING ON CARBON DIOXIDE, OTHER GREENHOUSE GASES, AND RELATED MEASUREMENT TECHNIQUES, 19th, August 27-31, 2017, Empa Dübendorf, Switzerland. Abstract... Geneva, Switzerland: World Meteorological Organization, 2017. p. P54-P54.

    Abstract: The tropical rainforests have an amount of carbon stored into its plants and soil comparable to half of the amount of atmospheric carbon contained at the atmosphere before the start of industrialization at the 18th century. Among the tropical regions, the Amazon forest covers the largest area and also hosts the largest carbon pool (~200 PgC), corresponding for 50% of its biome globally (1) . Considering the capability of rapid release and the amount of storage carbon, there are surprisingly few studies of emission ratios (2) and, in order to elucidate the actual contribution and the carbon emission from biomass burning in the Amazon Basin, measurements of carbon monoxide are an important tool. We will report results of a pan-Amazon low troposphere program used small airplanes, in 7 study sites from 2000 to 2016. The aircraft measurement program was started in 2000 with monthly/biweekly vertical profile sampling at SAN (2.86S 54.95W). From December 2004 to December 2007 we performed vertical profiles at MAN (Dec 2004 / Dec 2007). In 2010, a new step in our program was started. We added three more aircraft sites: TAB (5.96S 70.06W), RBA (9.38S 67.62W) and ALF (8.80S 56.75W). In 2013 TAB site was moved to TEF (3.39S 65.6W) and we add two more aircraft sites with vertical profiles from 300m to 7300 m, at Salinópolis (SAH 0.60S; 47,37W) near the Atlantic coast and RBH at the same place then RBA, in the western Amazon. The Amazon Basin biomass burning carbon emissions have been determined by applying a mass balance technique to carbon monoxide (CO) measured from vertical profiles in sites over the Amazon Basin, which is compared with carbon dioxide (CO2) emission when it is a clear biomass-burning plume in the vertical profile (3). We will present these CO results that is related to biomass burning and compare the carbon monoxide emissions with those from carbon dioxide, resulting in a ratio of carbon biomass burning emission which we will analyse with respect to climate, deforestation and number of fire hot spots.

    Como referenciar este item
    Icon

  • IPEN-DOC 24271

    OLIVEIRA, K.G. de; VIEIRA, D.P. ; COURROL, L.C.. Synthesis and characterization of 5-ALA gold nanoparticles: photo and sonosensitizer agent for atherosclerosis. In: INTERNATIONAL CONFERENCE ON LUMINESCENCE, 18th, August 27 - September 01, 2017, João Pessoa, PB. Abstract... São Paulo, SP: Sociedade Brasileira de Química, 2017. p. 304-304.

    Abstract: Atherosclerosis is a chronic inflammatory disease and the main cause of human death worldwide. Studies have proposed that macrophages play a significant role in the development, progression, and destabilization of atherosclerotic plaques[1]. Thus, reduction of macrophages from plaque represents a new strategy for the treatment of atherosclerosis. Photodynamic and Sonodynamic therapies (PDT and SDT, respectively) are emerging as new atherosclerosis treatments [1, 2]. The subsequent generation of free radicals by activated photo and sonosensitizers can lead to apoptotic cell death. The use of gold nanoparticles (AuNPs) as the vehicle for a sensitizer delivery improves reactive oxygen species formation [3]. Previous works demonstrated that aminolevulinic acid (5-ALA) mediated PDT could reduce macrophage content and inhibit plaque progression, indicating a promising approach to treat inflamed atherosclerotic plaque[4]. In this study ALA:AuNps functionalized with polyethylene glycol (PEG) were synthesized mixing 5-ALA with tetrachloroauric(III) acid in milliQ water solution followed by photo reduction with 300 Watts Xenon lamp. The synthesized nanoparticles were characterized by UV/Vis optical absorption, and electron microscopy. Singlet oxygen generation efficiency was measured by trapping with 1,3-diphenylisobenzofuran for irradiations with 590 nm LED (~100 mW) and pulse ultrasound irradiation (1 and 3W/cm2 with 1.0 and 2.0 MHz ). The potential use of ALA:AuNps as a sensitizer for photo and sonodynamic therapies were investigated on THP-1 macrophage. Cytotoxicity test were also described. The findings suggested that ALA:AuNps under LED illumination and ultrasound had photo and sonodynamic effect on THP-1 macrophages via generation of intracellular singlet oxygen, indicating that ALA:AuNps could be used as a novel photo and sonosensitizer for atherosclerosis.

    Palavras-Chave: aluminium arsenides; aminolevulinic acid; aqueous solutions; arteriosclerosis; electron microscopy; emission spectra; gold; macrophages; nanoparticles; oxygen; particle size; polyethylene glycols; pulsed irradiation; sensitizers; synthesis

    Como referenciar este item
    Icon

  • IPEN-DOC 24432

    CAREZZATO, G.L. ; COUTO, C.P. ; ROSSI, J.L. ; MARTINEZ, L.G. ; TURRILLAS, X.. A versatile setup in reflection mode for in situ diffraction patterns acquisition from flat polycrystalline specimens bathed in a liquid medium. In: RAU ANNUAL USERS MEETING LNLS/CNPEM, November 22-24, 2017, Campinas, SP. Abstract... 2017. p. 50-50.

    Abstract: A cell to perform in situ diffraction measurements of specimens regularly immersed in a liquid medium has been developed. The assembly (see Fig. 1) has been adapted to work in beamline XRD2 in reflection mode. Basically consists of a polypropylene box with two windows made of poliimide to allow the passage of X-rays (incident and diffracted) at lower angles. The flat sample is placed in the middle of the box that is on top of the goniometer head. For safety reasons the central box is positioned over a tray to avoid spillage of liquid. On the bottom of the cell there is a connection to the pipe linked to the syringe. The syringe is driven by a beamline stepping motor. This way it is easy to synchronise the filling and evacuation of liquid from the cell with the actual data acquisition of diffraction patterns. The idea is to soak the flat specimen with the liquid and then remove it to acquire the diffraction data. This can be done in a sequential way for several hours to monitor the crystalline phases present on the surface (or rather a few microns deep) of the flat specimen. Various reactions can be investigated this way, provided that the sample is flat. Ceramics, metals, and polymers in contact with liquids could be studied. Preliminary tests have been performed in two theta – theta geometry on metal plates in contact with acid solutions to simulate accelerated corrosion. However a large variety of experiments with other geometries, (grazing incidence) could be carried out and of course this assembly could be used on SIRIUS with better time resolution.

    Como referenciar este item
    Icon

  • IPEN-DOC 24390

    WETTER, N.U. ; JORGE, K.C.; ALVARADO, M.E.A.; MELO, E.G. de; LOPES, A.T.; CARRENO, M.N.P.; CHAVEZ, M.I.A.. Highly directional random laser in a HC-ARROW microfluidic channel connected to a reservoir. In: WORKSHOP EM MICROFLUIDICA, 7., 31 de julho - 02 de agosto, 2017, São Paulo, SP. Resumo expandido... 2017.

    Abstract: Coherent light sources are used in optofluidic devices for real-time system control and quantitative analysis of important process parameters in general. However, generation and transport of coherent light poses high demands on material purity, quality and finish increasing the device cost by orders of magnitude when compared to simpler microfluidic devices without the optic part. In this work, we developed a laser within such a device using traditional technologies for fabrication of microfluidic devices. The laser is composed of a reservoir containing the gain media and its beam is transported by microchannel waveguides. The on-chip laser device can be pumped externally and emits a highly collimated beam.

    Palavras-Chave: coherent radiation; light sources; lasers; diffusion; multiple scattering; dye lasers; waveguides; optical systems; randomness

    Como referenciar este item
    Icon

  • IPEN-DOC 24267

    DAMIANI, RENATA; FEITOSA, THAIS; DAKIC, VANJA; SILVA, JOSEMAR; CUNHA, TATIANA; NORONHA, MARCOS; HIGA, OLGA ; ALEPEE, NATHALIE; PELLEVOISIN, CHRISTIAN; BACELLAR, MARIANO; BALOTTIN, LUCIENE; VECCHI, RODRIGO de; MEDEIROS, FABIANA . Use of in vitro methods according to OECD GD 129 and OECD TG 439 to classify children′s articles aligned with the UN GHS principles. In: WORLD CONGRESS ALTERNATIVES AND ANIMAL USE IN THE LIFE SCIENCES, 10th, August 20-24, 2017, Seattle, Washington, USA. Abstract... 2017.

    Abstract: Alternative Methods Network (RENAMA), National Institute of Metrology, Quality and Technology (INMETRO), Rio de Janeiro, Brazil, 4Schools Articles Safety Brazilian Technical Committee (CEE 102), Brazilian Association of Technical Standards (ABNT), São Paulo, Brazil, 5Biotechnology Department, Nuclear and Energy Research Institute (IPEN/CNEN-SP), São Paulo, Brazil, 6Research and Innovation, L’Oréal Research and Innovation, Aulnay-sous-bois, France, 7Research and Innovation, Episkin Academy, Lyon, France Schools Articles Safety Brazilian Technical Committee (TC/ABNT CEE 102) has taken up the challenge to update the national safety standard ABNT NBR 15236:2016 that complies with the regulations and guidelines on alternatives testing. The current aim was to provide an in vitro strategy for risk assessment of school articles with data integration following OECD GD129 & TG439. In Vitro Acute Toxicity and SkinEthicTM Reconstructed Human Epidermis Skin Irritation methods were adapted from medical devices protocols by measuring cytotoxic effects of extracts prepared according ISO10993. Results obtained on >150 school articles (pens, pencils, crayons, watercolor, adhesives, correction fluid) were reproducible. 100% concordance with UN GHS classification for discriminating approval (95%) versus non-approval (5%) was observed. In conclusion, these results are important to ensure that regulatory authorities in Brazil are provided with the appropriate data required for decision-making.

    Como referenciar este item
    Icon

  • IPEN-DOC 24266

    DAMIANI, RENATA; VALGODE, FLAVIA; PASSOS, PRISCILA; VALADARES, MARCOS; BIAGI, DIOGO; HIGA, OLGA ; MEDEIROS, FABIANA . Cytotoxicity model using human cardiomyocytes derived from pluripotent cells (iPSCs) for cardiotoxicity safety assessment. In: WORLD CONGRESS ALTERNATIVES AND ANIMAL USE IN THE LIFE SCIENCES, 10th, August 20-24, 2017, Seattle, Washington, USA. Abstract... 2017.

    Abstract: In contemporary drug development, preclinical and clinical evaluation, cardiac safety concerns arise from a variety of drug-tissue interactions, including direct myocyte toxicity. In this study, in vitro cytotoxic studies were conducted on GLP conditions in human cardiomyocytes derived from pluripotent cells (iPSCs). Before testing, cell population purity, above 90%, were confirmed by troponin 1 antibody biomarker. iPSCs cells were incubated with DMSO and Doxorubicin for 48 hours in a 96-well plates. Three different dyes – MTS, MTT and NR – were used to evaluate cell viability. The results showed that the iPSCs derived cardiomyocyte model was sensitive to predictive moderate and severe drug-induced cardiotoxicity. According to these results, the in vitro cytotoxicity model using iPSCs derived cardiomyocytes can be applied in the safety assessment of novel drug candidates as well as to identify compounds that may cause cardiotoxicity.

    Como referenciar este item
    Icon

  • IPEN-DOC 24265

    SILVA, FELIPE D. ; SUZUKI, MIRIAM ; OLIVEIRA, JOAO ; FREIRE, RENAN ; BARTOLINI, PAOLO ; SOARES, CARLOS ; AFFONSO, REGINA . Expression of human prolactin in HEK293T using different transfection reagents. In: ANNUAL MEETING OF THE BRAZILIAN SOCIETY FOR BIOCHEMISTRY AND MOLECULAR BIOLOGY, 46th, July 27-30, 2017, Águas de Lindóia, SP. Abstract... São Paulo, SP: Sociedade Brasileira de Bioquímica e Biologia Molecular, 2017.

    Abstract: INTRODUCTION Prolactin is a hormone produced by the pituitary gland with numerous functions, such as lactation, reproduction, osmotic and immune regulation. This hormone is upregulated in cases of lack of lactation, infertility and cancer. Recombinant prolactin has been produced in Escherichia coli with an initial methionine which may cause immunological reactions, or in its authentic form in mammalian cells. Our laboratory has already synthesized human prolactin (hPRL) without initial methionine in E. coli periplasm and Chinese hamster ovary cells. CHO cells have been widely used in the synthesis of human recombinant proteins because of their similarity with human post-translational modifications as glycosylation. The HEK293, a human embryonic kidney cell, can do diverse glycosylation depend on culture conditions. OBJECTIVES This work compares different transfection reagents in the production of hPRL in HEK293T. MATERIALS AND METHODS The hPRL cDNA was inserted into the pEDdc vector donated by the Genetics Institute, USA. Three transfection reagents were used: LipofectamineTM (Thermo), XfectTM (Clontech), and ExpiFectamineTM (Thermo). HEK293T cells, a human strain, were cultured in 10 cm² Ø petri dishes with RPMI 1640 medium with 10% fetal bovine serum (FBS). After transfection, the medium was changed to serum free CHO-S-SFM II (Invitrogen, USA). 100% of the medium was collected and changed every two days. The collected medium was stored at -80°C. Samples were analyzed by SDS-PAGE, Western blotting and HPLC. DISCUSSION AND RESULTS The glycosylated and non-glycosylated hPRL forms secreted into the culture medium were confirmed by Western blot and RPHPLC in the three transfected cultures in recombinant human cells. The reagent with the best result was Xfect (2 μg/mL), followed by Lipofectamine (1.6 μg/mL) and Expifectamine (1.2 μg/mL). CONCLUSION The transient expression of hPRL using HEK293T cells enable laboratory production of glycosylated hPRL for future studies of N-glycans produced by these cells.

    Como referenciar este item
    Icon

  • IPEN-DOC 24264

    SILVA, F.D. ; SEVILHANO, T.C.A. ; FREIRE, R.P. ; SUZUKI, M.F. ; OLIVEIRA, J.E. ; PERONI, C.N. ; RIBELA, M.T.C.P. ; BARTOLINI, P. ; SOARES, C.R.J. . Transient expression of recombinant human prolactin and thyrotropin in human embryonic kidney (Expi293FTM) suspension cells. In: CONFERENCE ON PROTEIN EXPRESSION IN ANIMAL CELLS, 13th, September 24-28, 2017, Valencia, Spain. Abstract... 2017.

    Abstract: Human prolactin (hPRL) and human thyrotropin (hTSH) are pituitary polypeptide hormones with key functions in the physiological regulation of the human body. hPRL is highly secreted during lactation, has important action in reproduction and for immunoregulation, among other functions. hTSH is related to the control of thyroid gland. The Chinese Hamster Ovary (CHO) and Human Embryonic Kidney (HEK293) cells are the most used hosts for expression of recombinant human proteins because they can be easily cultured in suspension conditions, and express high levels of proteins that have a relative similarity in post-translational modifications compared to their human counterparts. Our laboratory has experience in the synthesis of these proteins in the Escherichia coli periplasm (hPRL), adhered CHO (hPRL and hTSH), suspension CHO (hPRL) and adhered HEK293T cells (hTSH). The aim of this work was to produce hPRL and hTSH in suspension Expi293FTM cells for their characterization. The hPRL and hTSH cDNA were introduced into the commercial plasmid pcDNATM 3.4-TOPO® and 30 μg of these plasmids were used to transfect 30 mL of suspension Expi293FTM cells (2.5 x 106 cells/mL) in a 125 mL erlenmeyer, using 81 μL of ExpiFectamineTM transfection agent. After 16 h of transfection, 150 μL of Enhancer 1 and 1.5 mL of Enhancer 2 were added and the culture was maintained in an incubator at 37 °C, 8% CO2, at 125 rpm in orbital shaker. Samples of conditioned media (Expi293TM expression medium) were collected during 4 days and stored at -80 °C. These were analyzed by SDS-PAGE, ELISA, Western blotting, and HPLC. For the first time, hPRL and hTSH, were transiently expressed in human (Expi293FTM) suspension cells, the expression levels reaching, on the 3rd day, 46 μg of hPRL/mL and 116 μg of hTSH/mL. These results show that the expression is clearly dependent on the characteristics of the protein and that this methodology is very efficient to obtain high levels of human glycoproteins in a short time and will allow us to purify them and compare their glycosylation profiles of these to CHO-derived and human native pituitary hormones.

    Palavras-Chave: hormones; embryos; kidneys; trh; animal cells; cho cells; lth

    Como referenciar este item
    Icon

  • IPEN-DOC 24268

    BONFIM, LETICIA ; GONÇALVES, KARINA O.; COURROL, LILIA C.; VIEIRA, DANIEL P. . Iron oxide ferromagnetic nanoparticles functionalized with mPEG-CN and L-Lysine bind efficiently to cells in vitro. In: PAN AMERICAN CONGRESS OF NANOTECHNOLOGY, 1st; FUNDAMENTALS AND APPLICATIONS TO SHAPE THE FUTURE, November 27-30, 2017, Guarujá, SP. Abstract... 2017.

    Abstract: Iron oxide nanoparticles were synthesized using an alkaline coprecipitation protocol under N2 atmosphere in order to produce cell-adherent ferromagnetic particles (CAFP). To promote functionalization and biocompatibility, methoxypolyethylene glycol activated with cyanuric chloride was added to nanoparticle suspensions and stirred for one hour at room temperature. mPEG-CN is a polymer which adheres to surface of nanoparticles, improving biocompatibility. In addition, it reacts predominantly with amine groups such as found on L-lysine, forming a biocompatible shell. L-Lysine is well-know aminoacid whose positive (in physiologic pH) charge will bind to cell surfaces. mPEG-CN coated particles were washed with ethanol to remove excess and further washed three times in sterile deionized water. L-Lysine solution (1mg/mL) was added (1:50, v/v) in five steps of five minutes each to NP and kept under sonication. Subsequently this particle suspension was added (100μL in a 25cm2 culture flask) to a human melanoma cells (SKMEL- 37) culture and incubated for 24 hours at 37°C (5% CO2). The nanoparticles were characterized by FTIR, x-ray diffraction and zeta potential. By optical microscopy it was possible to verify that the nanoparticles adhered to the cell membrane and no changes in cell morphology were observed. mPEG-CN and L-Lysine functionalization was shown to be useful to produce CAFP. Further studies will use this protocol to perform magnetic levitation cell cultures.

    Como referenciar este item
    Icon

  • IPEN-DOC 23459

    ANA, PATRICIA A.; BENETTI, CAROLINA; BACHMANN, LUCIANO; ZEZELL, DENISE M. . Structural characterization of dentin irradiated with Er,Cr:YSGG laser and fluoride for caries prevention. In: CONFERENCE ON LASERS AND ELECTRO-OPTICS, May 14-19, 2017, San Jose, California, USA. Resumo expandido... Washington, DC, USA: OSA, 2017. p. JTu5A.5.

    Abstract: Er,Cr:YSGG laser induces the formation of bruxite and tetracalcium phosphate, as well as decreases the content of protein and water on dentin tissue, even when associated with a fluoride gel and at low energy densities.

    Como referenciar este item
    Icon

  • IPEN-DOC 23457

    ZEZELL, DENISE M. . FTIR spectroscopy for diseases diagnosis. In: ENCONTRO DE FISICA, 03-07 de setembro, 2016, Natal, RN. Abstract... São Paulo: Sociedade Brasileira de Física, 2016.

    Abstract: Mid-infrared spectroscopy is a technique by which the chemical structure of an analyzed material can be identified; it also allows the semi-quantitative analysis of the components of the material. It has been already shown that Fourier transform infrared spectroscopy (FTIR) can be used to evaluate the effects of high-intensity laser irradiation on dentin and enamel tissues,as well as for the study of bone properties and several pathologies, such as lung, thyroid and skin cancer. The structural and biochemical changes associated with the development of enamel caries and also with the interaction of laser irradiation with the enamel, suggest that vibrational spectroscopy are promising techniques to differentiate sound and carious enamel, as well as detect changes due to laser irradiation. Considering that there is no agreement in the literature on the chemical changes promoted by the irradiation of Nd:YAG and Er,Cr:YSGG for preventive purposes on enamel, our studies aimed to determine these changes by FTRaman and FTIR spectroscopy and to investigate the influence of laser irradiation before or after the application of topical fluoride on the development of caries in vitro. Nonmelanoma skin cancers represent 95% of cutaneous neoplasms. Among them, squamous cell carcinoma (SCC) is the more aggressive form and shows a pattern of possible metastatic profile. In this work, we used Fourier transform infrared spectroscopy (FTIR) spectroscopy to assess the biochemical changes in normal skin caused by squamous cell carcinoma induced by multi-stage chemical carcinogenesis in mice. Changes in the absorption intensities and shifts were observed in the vibrational modes associated to proteins, indicating changes in secondary conformation in the neoplastic tissue. Hierarchical cluster analysis was performed to evaluate the potential of the technique to differentiate the spectra of neoplastic and normal skin tissue, so that the accuracy obtained for this classification was 92%. We develop a methodology to interpret hyperspectral imaging data and protein conformational changes observed in nomal thyroid tissue. Raw image datasets were imported into software written in-house in the MATLAB environment and processed to yield pseudo-color images of the tissue sections. All spectra were vector normalized, noisefiltered, and corrected for water-vapour contributions and scattering effects before being subjected to Hierarchical Cluster Analysis (HCA) and correlated with histological structures obtained from images of H&E-stained parallel tissue sections. We successfully identified a protein structural heterogeneity that can be correlated with the spatially resolved amount of iodine in the thyroglobulin structure of colloids and follicular cells. The chemical carcinogens from tobacco are related to over 90% of lung cancers around the world. The risk of death of this kind of cancer is high because the diagnosis usually is made only in advanced stages. Therefore, to develop new diagnostic methods for detecting the lung cancer in earlier is very important stages. The second derivate of spectra indicates that there are displacement in 1646 cm-1 (amine I) and 1255 cm-1 (DNA), allowing the possibility to differentiate the e10 lung normal cells from e10 lung cells transformed by tobacco substances (NKK) with accuracy of 89,9%.

    Como referenciar este item
    Icon

  • IPEN-DOC 23456

    AMARAL, M.M. ; TEIXEIRA, L.R.C. ; CARVALHO, M.T.; GOMES, A.S.L.; ZEZELL, D.M. . Hemangioma vascular lesion characterization by optical coherence tomography. In: ENCONTRO DE FISICA, 03-07 de setembro, 2016, Natal, RN. Abstract... São Paulo: Sociedade Brasileira de Física, 2016.

    Abstract: Hemangioma vascular lesions are common childhood tumors appearing mainly in the neck and head. It affects 10% of children worldwide [1]. In most cases the lesions does not bring consequences for the patient's health, although some patient can develop complications caused by tissue deformities. In extreme cases, it could be a life risk. The early diagnosis of the lesion could lead to an early treatment and a reduction on its aesthetic and psychological consequences. In this work, we evaluate the use of the Optical Coherence Tomography to differentiate between hemangioma vascular lesions from normal skin. Using a swept source OCT (9 m and 18 m axial and lateral resolution) 541 images of hemangioma lesion and 50 image of normal skin on the hand region was acquired. IMIP Ethics Committee approved this study (protocol no. 728.993). In order to characterize the normal skin and the hemangioma vascular lesion it was implemented an automated analysis using Matlab ©. Two approaches was implemented, a morphological analysis [2] to evaluate the epidermis thickness and an attenuation coefficient analysis [3] to evaluate the optical feature of the tissue. It was possible to evaluate the depth distribution of epidermis for booth normal skin and hemangioma lesion. Normal skin presented a thicker epidermis layer and a broader distribution, while hemangioma lesion presented a narrower epidermis layer and uniform distribution. The attenuation coefficient of hemangioma lesion presented 9.2% higher values than normal skin. Booth approaches proved to be valid for hemangioma diagnosis and could be complementary to each other and the combination of these approaches will be discussed in this work.

    Como referenciar este item
    Icon

  • IPEN-DOC 23315

    MORAES, LETICIA P.R. de ; MARANI, DEBORA; ESPOSITO, VINCENZO; FLORIO, DANIEL Z. de; FONSECA, FABIO C. . Synthesis and characterization of 2D layered gadolinium-doped cerium oxide (CGO) nanomaterials. In: INTERNATIONAL CONFERENCE ON SOLID STATE IONICS, 21th, June 18-23, 2017, Padua, Italy. Abstract... 2017.

    Abstract: By the virtue of versatility in composition, morphology, and structure, two-dimensional (2D) layered nanomaterials have attracted in the last decade huge interest. Such materials, consisting in stacked charged nanosheets intercalated with opposite charged exchangeable anions, are of great potential for the design and fabrication of nanomaterials in many applications. Indeed, the interlayer gallery provides a flexible space to accommodate various sized molecules (e.g. pollutants) and tune specific active sites at the atomic space (e.g. catalyst materials). The interest for 2D layered nanomaterials is also associated with the possibility of obtaining via exfoliation ultra-thin nanosheets with lateral dimensions of hundreds of nanometres and thickness of few nanometres. This unique class of nanomaterials has shown many unprecedented properties mainly originating from the dimensional anisotropy and nano-confinement effects. Herein we propose novel 2D layered ceria based oxides (e.g. CGO) synthesized via the heterogeneous precipitation. CGO materials were selected because of their strategic relevance in many technological applications (e. g. catalysis and electrochemical devices). The synthesized CGO layered materials were characterized for their composition, morphology and crystallographic features. The combined experimental results indicated that the layered CGO, with tunable dopant concentration, can be obtained in different morphologies by controlling the synthesis parameters.

    Como referenciar este item
    Icon

  • IPEN-DOC 23323

    RAMANATHAN, L.V. ; PILLIS, M.F. ; DE ARAUJO, E.G.; CORREA, O.V. . Preparation and characterization of mocvd thin film chromium dioxide coatings. In: CONGRESSO BRASILEIRO DE CERAMICA, 61., 04-07 de junho, 2017, Gramado, RS. Resumo... 2017. p. 2601-2601.

    Abstract: Chromium dioxide (Cr2O3) films have been widely used to increase the corrosion and wear resistance of metallic substrates. Many techniques have been used to deposit Cr2O3 films on a variety of substrates. This paper presents the preparation of Cr2O3 thin films using a custom made horizontal metal-organic chemical vapor deposition (MOCVD) apparatus at 600 ºC with film growth pressure of 2 mbar. Chromium acetylacetonate was used as the chromium precursor and to select the temperature in nitrogen at which to use this precursor in the MOCVD apparatus, its mass loss as a function of temperature was determined with a thermobalance. The Cr2O3 films were characterized using scanning electron microscopy and x-ray diffraction analysis. The isothermal oxidation behavior of Cr2O3 film coated carbon steel at 600 ºC in air was also determined using a thermogravimetric analyzer. The Cr2O3 thin film increased markedly the oxidation resistance of the steel.

    Como referenciar este item
    Icon

  • IPEN-DOC 23317

    MUCCILLO, R. ; MUCCILLO, E.N.S. . Simultaneous evaluation of linear shrinkage and electrical behavior of electroceramics during sintering. In: CONGRESSO BRASILEIRO DE CERAMICA, 61., 04-07 de junho, 2017, Gramado, RS. Resumo... 2017. p. 1497-1497.

    Abstract: Sintering a ceramic green pellet promotes microstructural evolution from packed particles composed of adjoined particles and pores to a consolidated body composed of grains and interfaces. As the impedance spectroscopy technique allows for detecting the main components of a ceramic body by separating in the frequency domain the electrical resistivity of each component, a sample inserted in a dilatometer was connected, via platinum electrodes and leads, to an impedance analyzer. The connection to the impedance analyzer could also be switched to a power supply for flash sintering experiments. In situ electrochemical impedance spectroscopy measurements of yttria-stabilized zirconia and yttrium/zirconium-doped barium cerate were performed during conventional and flash sintering experiments. The analysis of the impedance spectroscopy diagrams under heating (before either conventional or electric field-assisted sintering) and under cooling (after) provides evidence of densification with pore elimination and welding of grains.

    Como referenciar este item
    Icon

  • IPEN-DOC 23316

    MUCCILLO, E.N.S. ; GROSSO, R.L. ; CARVALHO, L.A. . Preparação e caracterização da zircônia estabilizada com ítria preparada por métodos químicos. In: CONGRESSO BRASILEIRO DE CERAMICA, 61., 04-07 de junho, 2017, Gramado, RS. Resumo... 2017. p. 1498-1498.

    Abstract: O condutor iônico de zircônia contendo 8% mol ítria (8YSZ) é atualmente utilizado em células a combustível de óxido sólido de altas temperaturas (acima de 850ºC), além de possuir outras aplicações na área de eletroquímica de sólidos. Neste trabalho, foi investigado o efeito do método de síntese nas características físicas dos pós de 8YSZ obtidos por precipitação simultânea e complexação de cátions. Para fins comparativos foram também preparadas amostras pelo método convencional de reação em estado sólido. Os métodos de síntese apresentaram rendimentos de 84% (complexação de cátions) e 89% (precipitação simultânea), inferiores ao método convencional (95%). A morfologia dos pós sintetizados é constituída por aglomerados porosos de partículas, com ampla distribuição de tamanhos, como observado por medidas de espalhamento laser e microscopia eletrônica de varredura. Os aglomerados formados nos pós sintetizados pela complexação de cátions apresentam maior resistência. Com isto a densidade após a sinterização (1200-1500ºC) é menor nas amostras sintetizadas por este método de síntese.

    Como referenciar este item
    Icon

  • IPEN-DOC 23401

    SILVA, T.F.A. da ; COSTA, C.H.; VIANNA JUNIOR, A.S.; ROSSI, W. de ; MAZZOCCHI, V.L. ; SAMAD, R.E. ; VIEIRA JUNIOR, N.D. ; BALDOCHI, S.L. . Microfluidic synthesis of NaYF4:Yb/Er nanoparticles. In: WORKSHOP EM MICROFLUÍDICA, 7., 31 de julho - 3 de agosto, 2017, São Paulo, SP. Abstract... 2017.

    Abstract: Synthesis of fluoride nanoparticles were studied using microfluidic devices. Experiments were performed in a glass microchip designed and produced at IPEN with femtosecond laser machining for nanoparticles synthesis and with commercial Asia chemistry modules system. NaYF4 co-doped with Yb3+/Er3+ were obtained in both systems but additional experiments for synthesis parameter optimization as well as in the IPEN microchip design are necessary to obtain single phase nanoparticles.

    Como referenciar este item
    Icon

  • IPEN-DOC 23400

    ROSSI, WAGNER de ; HERRERA, CRISTHIANO da C.; VIEIRA JUNIOR, NILSON D. ; SAMAD, RICARDO E. . Microfluidic devices produced by micromachining with ultra-short laser pulses. In: WORKSHOP EM MICROFLUÍDICA, 7., 31 de julho - 3 de agosto, 2017, São Paulo, SP. Abstract... 2017.

    Abstract: Complete microfluidic systems are being produced by ultra-short laser pulses machining in BK7 optical glass. Small structures have been developed to form various components of a microfluidic circuit, such as microchannels, micro-valves and microreactors. The flow of the reactants is controlled by an external pneumatic system together with microvalves incorporated in the circuits. A program in Labview enables complete control of processes.

    Como referenciar este item
    Icon

  • IPEN-DOC 23314

    MATSUI, J.M. ; ARATA, A. ; YOSHITO, W.K. ; USSUI, V. ; LIMA, N.B. ; LAZAR, D.R.R. . Avaliação da degradação hidrotérmica de compósitos de alumina em matriz de zircônia preparados a partir de pós sintetizados por coprecipitação. In: CONGRESSO BRASILEIRO DE CERAMICA, 61., 04-07 de junho, 2017, Gramado, RS. Resumo... 2017. p. 1900-1900.

    Abstract: A adição de alumina em biocerâmicas de zircônia estabilizada com 3 mol % de ítria (3Y-TZP) tem sido considerada uma alternativa eficiente para evitar a transformação acelerada da fase tetragonal para monoclínica em ambiente úmido, condição esta encontrada sob ação de fluidos corpóreos, tais como saliva e plasma sanguíneo. Esse processo, conhecido como degradação a baixa temperatura ou envelhecimento, pode provocar falha catastrófica deste material, inviabilizando a aplicação da cerâmica na área biomédica. Neste sentido, avaliou-se, no presente trabalho, a influência da concentração de alumina na degradação hidrotérmica de compósitos 3Y-TZP/Al2O3. Os compósitos foram preparados a partir de pós sintetizados pela rota de coprecipitação de hidróxidos. A concentração de alumina na 3Y-TZP foi estudada na faixa de 0,05 a 20% em massa. As amostras cerâmicas foram prensadas e sinterizadas a 1530oC por 2 horas e 1620oC por 1 hora. A degradação das amostras foi estudada in vitro a 150°C por 5, 25 e 70 horas em reator hidrotérmico pressurizado. As amostras (n=4) foram submetidas à análise de difração de raios X de acordo com o tempo de envelhecimento, acompanhando a curva cinética de transformação de fase. A porcentagem das fases cristalinas foi determinada pelo Método de Rietveld. A relação entre o tempo de envelhecimento e a concentração de fase monoclínica foi determinada pela equação de Avrami modificada por Kolmogorow (JMAK). Após envelhecimento a 150oC por 70 horas, todas as amostras contendo alumina apresentaram menor concentração de fase monoclínica, comparativamente à cerâmica Y-TZP, que apresentou 67,35% de fase monoclínica. Menores porcentagens de fase monoclínica após o envelhecimento hidrotérmico foram obtidas com a adição de 10 e 20% em massa de alumina na matriz de zircônia, sendo esses valores 57,84 e 53,04%, respectivamente.

    Como referenciar este item
    Icon

  • IPEN-DOC 23313

    MARCELLO, B.A. ; GERIBOLA, G.A. ; DE ARAUJO, E.G.; PILLIS, M.F. . Influência da morfologia no desempenho fotocatalítico de filmes de TIO2. In: CONGRESSO BRASILEIRO DE CERAMICA, 61., 04-07 de junho, 2017, Gramado, RS. Resumo... 2017. p. 2590-2590.

    Abstract: Dióxido de titânio apresenta estabilidade química em diversos meios, apresenta boa resistência mecânica e à corrosão, fotoestabilidade, e significativa atividade fotocatalítica. Trata-se do semicondutor mais utilizado como fotocatalisador. Neste trabalho filmes de TiO2 com espessura de aproximadamente 400 nm foram crescidos a 400 e 500ºC sobre borossilicato utilizando a técnica de deposição química de organometálicos em fase vapor. Análises por difração de raios-X sugerem a formação de somente anatase em ambos os casos. Os filmes crescidos a 400ºC apresentaram direção preferencial de crescimento (200), enquanto que os crescidos a 500ºC apresentaram crescimento preferencial na direção (112). As análises obtidas por microscopia eletrônica de varredura mostram que o filme crescido a 400ºC apresenta morfologia colunar densificada, e o filme crescido a 500º apresenta morfologia colunar porosa. O desempenho fotocatalítico dos filmes foi avaliado por espectrofotometria UV medindo-se os valores de absorbância em uma solução aquosa de concentração 5 mg/L, e pH 2 de alaranjado de metila, após 5h sob luz UV. Os resultados de degradação indicam um desempenho muito superior do filme crescido a 400ºC, o que sugere que a morfologia dos filmes tem papel importante na fotocatálise

    Como referenciar este item
    Icon

  • IPEN-DOC 23303

    GODOY, A.E. ; GARCIA, R.H.L. ; USSUI, V. ; LAZAR, D.R.R. . Caracterização microestrutural de 3Y-TZP/AL2O3 obtido por sinterização em dois estágios. In: CONGRESSO BRASILEIRO DE CERAMICA, 61., 04-07 de junho, 2017, Gramado, RS. Resumo... 2017. p. 1733-1733.

    Abstract: Compósitos de ZrO2 - Al2O3 apresentam boas propriedades mecânicas, alta resistência ao desgaste, estabilidade à altas temperaturas e são resistentes à corrosão. Estes materiais podem ser utilizados como biomateriais, ferramentas de corte e materiais estruturais. O objetivo deste trabalho é o estudo da sinterização em dois estágios de compósitos de ZrO2 - Al2O3. Esta técnica de sinterização inibe o crescimento acelerado de grãos que ocorre no estágio final mas não evita a densificação, podendo-se obter materiais densos com tamanho de grãos reduzidos. A preparação dos pós contendo 20% em massa de alumina, em matriz de zircônia estabilizada com 3 mol % de ítria, foi realizada por meio de coprecipitação. O pó foi seco a 80ºC em estufa por 24h e calcinado ao ar a 800ºC por 1 hora. Depois da compactação a 100 MPa as pastilhas foram sinterizadas em dois estágios: a 1550 ºC por 10 min. e 1500 ºC por 1 hora. As técnicas de caracterização dos pós incluíram determinação da área superficial específica pela técnica de adsorção gasosa, distribuição granulométrica dos aglomerados por difração a laser, difração de raios-X e microscopia eletrônica de varredura. As amostras sinterizadas foram caracterizadas por densidade aparente, difração de raios-X, microscopia eletrônica de varredura e medidas de dureza. Os pós são ligeiramente arredondados, com área superficial específica de cerca de 120m2/g e tamanho de aglomerados/partículas de aproximadamente 1,8μm. As pastilhas apresentaram microestruturas homogêneas com boa dispersão dos grãos de alumina na matriz e densidades superiores a 95% da densidade teórica.

    Como referenciar este item
    Icon

  • IPEN-DOC 23299

    CARVALHO, S.G.M. ; MUCCILLO, E.N.S. ; MUCCILLO, R. . AC electric field-assisted sintering of stabilized zirconias. In: CONGRESSO BRASILEIRO DE CERAMICA, 61., 04-07 de junho, 2017, Gramado, RS. Resumo... 2017. p. 1494-1494.

    Abstract: Green pellets of ZrO2:3 mol% Y2O3 and ZrO2: 10 mol% Sc2O3:1 mol% CeO2 were sintered by applying AC (500 Hz – 1.1 kHz) electric fields (typically 100 V.cm-1) during the first stage sintering stage (T < 1200oC). The experiments were carried out positioning the specimens inside a vertical dilatometer with platinum disks acting as electrodes in a capacitor-like setup. The shrinkage level was controlled by monitoring the dilatometer gauge. Under the same conditions of temperature and magnitude of the applied AC voltage, the results show that the higher is the frequency of the electric field, the higher are the attained shrinkage and apparent density. Microstructural analyses of surfaces of the flash sintered specimens show that the average grain size also depends on the frequency of the electric field for the same sintering temperature, sintering time, applied electric field and electric current limit. We propose that increasing the frequency of the electric current pulse (resulting from the applied electric field) leads to an increase of charge carriers collisions, therefore increasing the amount of Joule heating delivered to the specimen, which is the primary phenomenon responsible for the densification of the specimens.

    Como referenciar este item
    Icon

  • IPEN-DOC 23298

    ARATA, A. ; PRETTO, L.R. DE ; USSUI, V. ; LIMA, N.B. ; FREITAS, A.Z. ; MACHADO, J.P.B.; TANGO, R.N.; SOUZA, G.M.D. DE; LAZAR, D.R.R. . Efeito da porcentagem de fase monoclínica e profundidade da camada transformada na resistência mecânica da 3Y-TZP odontológica após o envelhecimento hidrotérmico pressurizado. In: CONGRESSO BRASILEIRO DE CERAMICA, 61., 04-07 de junho, 2017, Gramado, RS. Resumo... 2017. p. 1918-1918.

    Abstract: O objetivo deste estudo foi avaliar a relação entre a porcentagem de fase tetragonal para monoclínica (t-m) e profundidade da camada de transformação de fase com a resistência à flexão biaxial (FB) de uma cerâmica Y-TZP odontológica submetida ao envelhecimento hidrotérmico acelerado (EH). Discos sinterizados (Lava, 3M-ESPE) foram submetidos ao EH em reator pressurizado a 150°C por (n=8): 0, 5, 25, 70 e 140 horas e analisados por difração de raios X (DRX) e microscopia eletrônica de varredura (MEV) para calcular a profundidade de transformação de fase e a velocidade da frente de transformação. Após o EH os grupos foram submetidos ao teste de flexão biaxial (ISO 6872) e análise de variância 1 fator (ANOVA) (alfa=0,05). A relação entre profundidade da camada transformada e resistência a flexão biaxial foi avaliada pela Correlação de Pearson (alfa=0,05). Os resultados de DRX indicam que a Y-TZP apresentou comportamento sigmoidal de transformação de fase, devido à limitação da profundidade de penetração dos raios X (~6,3 microns). A porcentagem máxima de fase monoclínica observada foi de ~66%. Porém, a análise de MEV demonstrou o crescimento linear da frente de envelhecimento em função do tempo (0,52 microns/h). O ANOVA 1-fator apresentou redução, estatisticamente significante, de 1,3% e 15% da resistência a FB após 5 horas e 25 horas de envelhecimento hidrotérmico, respectivamente, em relação ao grupo controle (1123±75 Mpa). Houve correlação negativa entre profundidade da camada transformada e resistência à FB. Conclui-se que a porcentagem de fase monoclínica e a profundidade da zona de transformação de fase são informações críticas quanto a avaliação do efeito do envelhecimento hidrotérmico nas propriedades mecânicas da Y-TZP, uma vez que o aumento da camada transformada em função do tempo de EH a 150°C diminui a resistência à flexão biaxial da 3Y-TZP.

    Palavras-Chave: dentistry; ceramics; hydrothermal systems; x-ray diffraction; scanning electron microscopy; mechanical properties

    Como referenciar este item
    Icon

  • IPEN-DOC 23333

    SCHELL, JULIANA; CORREIA, JOAO G.M.; DEICHER, MANFRED; LUPASCU, DORU C.; VIANDEN, REINER; BARBOSA, MARCELO; CARBONARI, ARTUR . Studying after effects by gamma-gamma and electron-gamma perturbed angular correlations. In: TEMST, KRISTIAAN (Ed.); VANTOMME, ANDRE (Ed.); COTTENIER, STEFAAN (Ed.); PEREIRA, LINO (Ed.) INTERNATIONAL CONFERENCE ON HYPERFINE INTERACTIONS AND THEIR APPLICATIONS, July 3-8, 2016, Leuven, Belgium. Abstract... Leuven, Belgium: Instituut voor Kern- en Stralingsfysica, 2016.

    Abstract: Using electron-gamma perturbed angular correlations (PAC) experiments working side-by-side with gamma-gamma PAC on the same isomeric transitions, besides structural properties, additional information can be unambiguously obtained by following the electronic recombination at the atomic shells and the neighbor atoms after the emission of the conversion electron from the probe nuclei K, L, or M atomic shells. Such experiments can be envisaged, as well, to clear out gamma-gamma PAC experiments where the probing state is fed by electron capture decay. There, one K, L, M orbital electron is absorbed by a proton creating a hole when the atomic number changes from Z to Z-1. This causes a severe electronic rearrangement of the atomic shells accompanied by the emission of x-rays and Auger electrons. The atom is left in a highly ionized state and the recombination time – fast or slow – depending on the availability and mobility of host electrons determines if a transient effect is observed within the lifetime of the nuclear state used for PAC. This is the so called “after effect”, that if properly understood, can further contribute to learn about the interaction of the impurity probe with the host, eventually observing ionized states and determining electron mobility [1]. Illustrating this problematic we present and discuss in this work the study of TiO2 doping [2] using different PAC isotopes (111In/111Cd, 181Hf/181Ta, 111mCd/111Cd, 117Cd/117In).

    Como referenciar este item
    Icon

  • IPEN-DOC 23312

    CAVALCANTE, FABIO H. de M.; SALES, TATIANE S.N. ; DAY, TRAVIS; LEITE NETO, OSMAR F.S. ; PEREIRA, LUCIANO F.D. ; SAXENA, RAJENDRA N. ; CARBONARI, ARTUR W. ; MENONI, CARMEN. Influence of oxygen atmosphere in the annealing of HfO2 thin films studied by perturbed angular correlation spectroscopy. In: TEMST, KRISTIAAN (Ed.); VANTOMME, ANDRE (Ed.); COTTENIER, STEFAAN (Ed.); PEREIRA, LINO (Ed.) INTERNATIONAL CONFERENCE ON HYPERFINE INTERACTIONS AND THEIR APPLICATIONS, July 3-8, 2016, Leuven, Belgium. Abstract... Leuven, Belgium: Instituut voor Kern- en Stralingsfysica, 2016.

    Abstract: The thin films of HfO2 have been grown by dual ion beam sputtering (DIBS) on transparent quartz substrates (grade silica) and silicon wafers. The major benefits of the DIBS process are the increased packing density of the deposited films which makes them more bulk-like, the improved adhesion resulting from the mixing of the materials at the interfaces between each layer, and the reduction of the high tensile stress in the layers. Deposition conditions were adjusted to obtain polycrystalline as well as amorphous films. In this study the time differential perturbed angular correlation (PAC) spectroscopy was used to study the influence of oxygen atmosphere in the annealing of the HfO2 thin film. The PAC method is based on the hyperfine interaction of nuclear moments of the probe with extra nuclear magnetic fields or electric field gradients (EFGs). In the case of quadrupolar interaction, the experimental measurement gives the quadrupolar frequency νQ with respective distribution δ as well as the asymmetry parameter η of EFG. The presence of the 180Hf isotope in natural hafnium allows the possibility of using 181Ta as a probe nucleus formed by irradiating the samples with neutrons via 180Hf(n,γ)181Hf reaction. After irradiation, samples were annealed in oxygen atmosphere at different temperatures. The γ-γ PAC measurements were then carried out using a standard set up with four conical BaF2 detector scintillators with a time resolution of 0.6 ns (FWHM). Results show a structural transition from monoclinic to tetragonal in the annealed samples.

    Como referenciar este item
    Icon

  • IPEN-DOC 23311

    PEREIRA, LUCIANO F. ; MESTNIK-FILHO, JOSE ; CARBONARI, ARTUR ; CAVALCANTE, FABIO ; LEITE-NETO, OSMAR . First-principles calculations of the magnetic hyperfine field at Cd sites in RECd (RE = rare-earth element). In: TEMST, KRISTIAAN (Ed.); VANTOMME, ANDRE (Ed.); COTTENIER, STEFAAN (Ed.); PEREIRA, LINO (Ed.) INTERNATIONAL CONFERENCE ON HYPERFINE INTERACTIONS AND THEIR APPLICATIONS, July 3-8, 2016, Leuven, Belgium. Abstract... Leuven, Belgium: Instituut voor Kern- en Stralingsfysica, 2016.

    Abstract: Binary magnetic compounds based on rare-earth (RE) elements of the type REX, where X is a transition metal, with the simplest stoichiometry and crystalline cubic structure, are isostructural systems with different RE constituents, which differ only slightly in the crystallographic properties, but strongly in the magnetic properties. They thus offer excellent conditions for the separation of the magnetic from other solid-state parameters and permit the magnetism studies. However, in most RE compounds and, particularly when X=Cd, details of the magnetic structure at an atomic scale are not available mainly because is not possible to use neutron diffraction to investigate them. In this paper, the magnetic hyperfine field (mhf) at Cd sites in RECd compounds was studied by first-principles calculation. These compounds crystalizes in the CsCl prototype cubic structure (Pm-3m space-group) and order ferromagnetically below the Curie temperature with exception of PrCd, which presents antiferromagnetism. Recently, it was observed an unexpected transition in the mhf at 111Cd in DyCd below 40 K, when mhf vanishes [1]. We have used the density functional theory framework with full potential Augmented Planes Waves plus local orbitals (APW+lo) method embodied in the WIEN2k code to simulate electronic structures of the ferromagnetic and antiferromagnetic crystal cells in these compounds. For the exchange-correlation effects we chose local density approximation. The mhf at Cd sites and the formation energy were calculated for each compound as well as the density of states were obtained. Results of mhf are in very good agreement (less than 10%) with the experimental values previously reported [1]. Interestingly, for DyCd the energy for the formation of the antiferromagnetic ordering with (π, π, 0) structure is smaller than that for the ferromagnetic and others possible antiferromagnetic phases. As far as we know, it is the first time that such an excellent agreement between the calculated and experimental mhf at Cd sites is observed. Moreover, this results is even more important because the calculations were fully variational without the use of the Hubbard model which takes into account the on-site correlation of 4f electrons.

    Como referenciar este item
    Icon

  • IPEN-DOC 23399

    HERRERA, CRISTHIANO C.; RIBEIRO, MARTHA S.; SPENCER, PATRICK J. ; SAMAD, RICARDO E. ; VIEIRA JUNIOR, NILSON D. ; ROSSI, WAGNER de . Development of a microfluidic circuit with femtosecond laser technology for enzyme-linked immunosorbent assay validation. In: WORKSHOP EM MICROFLUÍDICA, 7., 31 de julho - 3 de agosto, 2017, São Paulo, SP. Abstract... 2017.

    Abstract: One of the great challenges in science today is to develop applications for disease diagnosis that can be accessible to the poorest populations distant from large centers. Using ultra-short laser pulses, we developed and machined a microfluidic circuit capable of replicating enzyme-linked immunosorbent assays (ELISA) with a much lower cost of materials. Microchannels etched in BK7 glass separated by a PDMS film form the basis of the system. The reagent flow control is done by pneumatic micro-valves controlled by an Arduino microcontroller through a Labview platform. The enzymatic reactions occurred under stopped-flow conditions, in a portion of the circuit constructed in a serpentine shape to facilitate the detection by an image processing software. This work presents the design of the microfluidic circuit developed and an ELISA test for characterization and validation of the results.

    Como referenciar este item
    Icon

  • IPEN-DOC 23398

    ZURLO, MARCIO N.; SANTOS, GIVANILDO A. dos; CINTRA, ELAINE P.; COUTO, ANTONIO A. ; OSORIO, WISLEI R.R.; TORRESI, ROBERTO M.. Corrosion resistance based on the microstructural array of an Al-3wt%Cu-1wt%Li alloy. In: BRAZILIAN MRS MEETING, 15th, September 25-29, 2016, Campinas, SP. Abstract... São Carlos, SP: Aptor Software, 2016. p. 1019-1020.

    Abstract: The high specific properties of Al-Li alloys have led to tremendous development effort aimed in particular at aerospace applications. Al-Li castings and cast alloys that combine the good properties of Al-Li alloys with foundry technology have great potential in both the aircraft and automotive sectors [1, 2]. In general, the corrosion behavior strongly depends on the structural morphology and chemical composition [3]. In this work, anAl-3wt%Cu-1wt%Li alloy was solidified under upward unsteady state heat flow conditions. Heat was directionally extracted only through a water-cooled bottom made of steel (SAE 1020). The aim of the present work is to investigate the influence of the microstructure of this alloy upon corrosion resistance. Experimental results include secondary dendrite arm spacings (l2), corrosion potential (ECorr), corrosion rate (iCorr), polarization resistance (R1) and capacitances values (ZCPE). The corrosion behavior was analysed by electrochemical impedance spectroscopy technique and Tafel extrapolation method conducted in a 3% NaCl solution at room temperature. Coarser dendritic structures tend to improve the corrosion resistance of an Al-3wt%Cu-1wt%Li alloy.

    Como referenciar este item
    Icon

  • IPEN-DOC 23397

    TINTI, VICTOR B.; FONSECA, FABIO C. ; FLORIO, DANIEL Z. de. Synthesis of Ni nanoparticles in lanthanum chromite ceramic matrix. In: BRAZILIAN MRS MEETING, 15th, September 25-29, 2016, Campinas, SP. Abstract... São Carlos, SP: Aptor Software, 2016. p. 657-657.

    Abstract: Lanthanum chromite is a well-known interconnector for solid oxide fuel cells. It presents electronic conductivity at high temperatures. Moreover it is very stable in oxidizing and reducing atmospheres. Due to its high stability this material is a promising matrix to produce and stabilize nanoparticles by exothermal reaction. The objective of the present work is to synthesize and stabilize nickel nanoparticles in a stable ceramic matrix. Compounds of (La1-xSrx)a(Cr1-yNiy)O3 (x and y = 0, 0.1, and 0.2; a = 1, and 0.8) were synthesized by Pechini method. The powders were heat treated in air at 1300 °C and 1600°C in attempt to solubilize NiO in the matrix. Then the samples were exposed to a reducing treatment in H2(g) flux at 900°C per 8 hours. XRD measurements were made using a D8 Focus, Bruker AXS. The data was acquired in a range of 2θ from 20° to 90°, with a step of 0,02° per second. Magnetic properties were investigated utilizing a SQUIDVSM from Quantum Design. Magnetic moment at constant magnetic field (100 Oe and 1000 Oe) was measured in a range of 2K to 300K. Analyses with variable magnetic field were performed at 2K, 196K and 390K in a rage from -5 up to 5 T. Samples were observed using TEM technique. The XRD results showed that the stoichiometric samples achieved desiderate phase. Compounds without Sr and non-stoichiometric lanthanum site showed an incomplete nickel solid solution. The addition of 10% of Sr decreases the Néel temperature from 289 K to 285K. Ni doping created a stronger effect, lowering the temperature down to 267 K , in the sample with 10% of dopant. After reduction is possible to observe peaks of Ni in the XRD, indicating that nickel was exoluted form the matrix. Images of TEM confirm the presence of nanoparticles with an approximate diameter of 3 nm. The reducing treatment increased the magnetic response.

    Palavras-Chave: ceramics; chromium oxides; heat treatments; lanthanum oxides; magnetic properties; nanoparticles; nickel; synthesis; transmission electron microscopy; x-ray diffraction

    Como referenciar este item
    Icon

  • IPEN-DOC 23396

    RUIZ, JESUS E.G.; RONCONI, LAIS; LAZARO, LOURDES M.Y.; CARCELLER, RENE C.; VALENZUELA, MARIA das G. da S.; MOURA, ESPERIDIANA B. ; RIVERA, JOSE L.V.; MOLINER, TANIA R.; DIAZ, FRANCISCO R.V.. Graphene oxide preparation with different sonication times. In: BRAZILIAN MRS MEETING, 15th, September 25-29, 2016, Campinas, SP. Abstract... São Carlos, SP: Aptor Software, 2016. p. 459-459.

    Abstract: Graphene oxide, graphene and derivatives thereof has shown a significant increase in the number of scientific research devoted to their study. One of the most studied areas is its application as nanofillers in polymer nanocomposites. This paper describes obtaining graphene oxide by simplified Huang procedure, by chemical oxidation. Purified aqueous dispersions of graphene oxide were sonicated for 15 min, 1.0 h; 2.0 h; and 3.0 h. Thickening of sonicated dispersions was accompanied by rheological measurements. After drying and grounded, the obtained materials were characterized by techniques such as XRD, FTIR, SEM and TEM. The reduction in average diameter with sonication time was followed by laser particle size distribution assays. Examples of substantial gains in mechanical and barrier properties obtained with graphene oxide/EVOH nanocomposites are shown.

    Como referenciar este item
    Icon

  • IPEN-DOC 23395

    RIBEIRO, ALEXANDRE N.; SANTOS, GIVANILDO A. dos; NAKAMOTO, FRANCISCO Y.; KALLAS, CLAUDETE; COUTO, ANTONIO A. ; MELO, HERCILIO G. de; HERNANDEZ, ROCIO D.P.B.. The influence of the microstructure upon corrosion resistance of an Al-10wt% Si-5wt%Cu alloy. In: BRAZILIAN MRS MEETING, 15th, September 25-29, 2016, Campinas, SP. Abstract... São Carlos, SP: Aptor Software, 2016. p. 1060-1061.

    Abstract: The need of the industries achieves better specific properties of materials, make to develop studies to meet this demand. For the automotive industry the most interesting properties are low specific weight, low coefficient of thermal expansion, wear resistance at high temperatures and high corrosion resistance. In this context, new materials have been considered, in particular AlSiCu alloys. [1, 2]. In general, the corrosion behavior strongly depends on the structural morphology and chemical composition [3]. In this work, an Al-10wt%Si-5wt%Cu alloy was solidified under upward unsteady state heat flow conditions. Heat was directionally extracted only through a water-cooled bottom made of steel (SAE 1020). The aim of the present work is to investigate the influence of the microstructure of this alloy upon corrosion resistance. Experimental results include primary dendrite arm spacing (l1) and capacitances values (ZCPE). The corrosion behavior was analysed by electrochemical impedance spectroscopy technique conducted in a 3% NaCl solution at room temperature. Coarser dendritic structures tend to improve the corrosion resistance of an Al-10wt%Si-5wt%Cu alloy.

    Como referenciar este item
    Icon

  • IPEN-DOC 23394

    RIBEIRO, ALEXANDRE N.; KALLAS, CLAUDETE; SANTOS, GIVANILDO A. dos; NAKAMOTO, FRANCISCO Y.; MORO, JOAO R.; COUTO, ANTONIO A. ; MELO, HERCILIO G. de. The effect of the microstructure upon corrosion resistance of an Al-10wt% Si-2wt%Cu alloy. In: BRAZILIAN MRS MEETING, 15th, September 25-29, 2016, Campinas, SP. Abstract... São Carlos, SP: Aptor Software, 2016. p. 1062-1062.

    Abstract: In general, the corrosion behavior strongly depends on the structural morphology and chemical composition. The literature shows relationships between the corrosion behavior and the structural morphology of the secondary dendrite spacing [1]. The objective of this study is to investigate the influence of the microstructure of an Al-10wt%Si-2wt%Cu alloy in its corrosion resistance. In this work, an Al-10wt%Si-2wt%Cu alloy was solidified under upward unsteady state heat flow conditions. Heat was directionally extracted only through a watercooled bottom made of steel (SAE 1020). The aim of the present work is to investigate the influence of the microstructure of this alloy upon corrosion resistance. Experimental results include primary dendrite arm spacings (l1) and capacitances values (ZC P E ). The corrosion behavior was analysed by electrochemical impedance spectroscopy technique conducted in a 3% NaCl solution at room temperature. Coarser dendritic structures tend to improve the corrosion resistance of an Al-10wt%Si-2wt%Cu alloy.

    Como referenciar este item
    Icon

  • IPEN-DOC 23393

    REIS, ADRIANO G. dos ; REIS, DANIELI A.P.; ABDALLA, ANTONIO J.; COUTO, ANTONIO A. ; SUGAHARA, TARCILA; OTUBO, JORGE. Surface characterization of plasma nitrided maraging 300 steel. In: BRAZILIAN MRS MEETING, 15th, September 25-29, 2016, Campinas, SP. Abstract... São Carlos, SP: Aptor Software, 2016. p. 865-865.

    Abstract: Maraging steels belong to a class of high strength steels with the combination of strength and toughness that are among the highest attainable in general engineering alloys. The term maraging is derived from martensite age hardening and denotes the age hardening of a low carbon, iron–nickel lath martensite matrix. These steels typically have very high nickel, cobalt and molybdenum and very low carbon content [1]. For aeronautical components requiring high strength and good wear resistance, such as, slat track, maraging steel possesses high strength, and good wear resistance can be achieved by plasma nitriding process, without sacrificing the strength of the bulk material [2]. In the present work, the surface of maraging 300 steel solution annealed and plasma nitrided was studied by atomic force microscopy (AFM) and microhardness. Samples were solution annealed at 820ºC for 1 h and then plasma nitrided by passing the gas mixture of H2 an N2 gases in the ratio of 3:1 under vacuum and it was carried out at 480ºC for 3 hours. 3D representation of nitrided and un-nitrided samples showed the nitrided samples with peak-valley structure, and the root mean square increase from 52 nm to 73 nm after superficial treatment. Plasma nitriding was effective to increase the microhardness from 331 HV to 1010 HV, and it is associated with the simultaneous aging and the iron nitrides formed.

    Como referenciar este item
    Icon

  • IPEN-DOC 23392

    REIS, SHIRLEY L. dos ; MUCCILLO, ELIANA N. dos S. . Effects of the additions of strontium gallate on Electrical conductivity of La0.9Sr0.1Ga0.8Mg0.2O3-δ. In: BRAZILIAN MRS MEETING, 15th, September 25-29, 2016, Campinas, SP. Abstract... São Carlos, SP: Aptor Software, 2016. p. 635-635.

    Abstract: Strontium and magnesium-doped lanthanum gallate La1-xSrxGa1-yMgyO3-δ (LSGM) is a promising solid electrolyte for using in solid oxide fuel cells, due to its high ionic conductivity at intermediate temperatures (600 – 800 ºC) compared to yttriastabilized zirconia (YSZ). In addition, LSGM has negligible electronic conductivity and high chemical stability over a broad range of oxygen partial pressures [1-3]. In this work, the composition La0.9Sr0.1Ga0.8Mg0.2O3-δ with small additions of strontium gallate was prepared by solid-state reaction and the influence of the additive on the ionic conductivity and phase composition was investigated. The sintered solid electrolytes achieved densities higher than 95% of the theoretical value and the average grain size amounts 2.40 μm after sintering at 1350°C. The contents of secondary phases decreased with increasing strontium gallate additions. The additive was found to have a beneficial effect on the bulk ionic conductivity.

    Como referenciar este item
    Icon

  • IPEN-DOC 23391

    PUGLIESI, REYNALDO ; PEREIRA, MARCO A.S. ; ANDRADE, MARCOS L.G. . Neutron tomography at IPEN-CNEN/SP: images and applications. In: BRAZILIAN MRS MEETING, 15th, September 25-29, 2016, Campinas, SP. Abstract... São Carlos, SP: Aptor Software, 2016. p. 1976-1977.

    Abstract: The neutron tomography is a non destructive testing technique used to inspect the internal structure of a sample by means of tridimensional digital images. Because of the neutron-matter interaction characteristics this technique can be used to inspect hydrogen-rich substances like ceramics, oil, grease, water, rubber, blood and others, even wrapped by thick metal layers. In this way, the information provided by neutrons are complementary to the ones provided by Xrays. The Brazilian Institute for Nuclear Technology IPEN-CNEN/SP has an equipment for neutron tomography which since Nov/2011 is operational and installed at the IEA-R1 Nuclear Research Reactor. This equipment is able to provide high quality tomographs and some important results obtained for Proton Exchange Membranes (PEM) cell, for an archaeological sample and for pottery, will be presented. Furthermore, details of its construction and its versatility, in the sense that by means of small adjustments is possible to obtain images by other neutron imaging techniques, will be also presented. Is very important enhance that the high quality of the obtained images is due to the excellence of the IEA-R1 reactor which is able to furnish neutron beams with adequate intensity for such purpose.

    Como referenciar este item
    Icon

  • IPEN-DOC 23390

    PORFIRIO, TATIANE C. ; MUCCILLO, ELIANA N. dos S. ; FRANÇA, YONE V. ; MARQUES, FERNANDO M.B.; MUCCILLO, REGINALDO . Properties of porous samaria-doped ceria ceramics with lithium fluoride as sacrificial pore former. In: BRAZILIAN MRS MEETING, 15th, September 25-29, 2016, Campinas, SP. Abstract... São Carlos, SP: Aptor Software, 2016. p. 666-666.

    Abstract: Porous ceria: 10 mol% samaria (10SDC) ceramic solid electrolytes were prepared by solid state reaction with 0-50 vol.% lithium fluoride (LiF). Consolidation was done by heating to the melting point of LiF for 30 min to form a liquid phase, followed by elimination of LiF by capillarity after heating to 1500° C for 2 h, promoting intergranular porosity and 10SDC skeletal densification. Apparent density was evaluated by the Archimedes method, pore distribution by scanning electron microscopy and electrical properties by electrochemical impedance spectroscopy in the 5 Hz - 13 MHz frequency range and temperatures from 300 to 550° C. The main results show that porous ceramics with high skeletal density are obtained with sacrificial LiF. Moreover, the total electrical resistivity is directly related to the pore volume fraction. High temperature vacuum impregnation of lithium-potassium carbonate eutectic compositions onto the porous 10 SDC was carried out to consolidate composite SDC-molten carbonate ceramic membranes with tunable transport properties, for selective carbon dioxide separation. The enhancement of the total electrical conductivity was evaluated by electrochemical impedance spectroscopy. Percolation of the molten carbonate through the permeable porous membrane was ascertained by EDX analysis on both parallel surfaces of the membranes.

    Como referenciar este item
    Icon

  • IPEN-DOC 23389

    PERROTTA, JOSE A. . RMB: the new brazilian multipurpose research reactor. In: BRAZILIAN MRS MEETING, 15th, September 25-29, 2016, Campinas, SP. Abstract... São Carlos, SP: Aptor Software, 2016. p. 1982-1982.

    Abstract: The Brazilian research reactors have a limited capacity for radioisotopes production, leading to a high dependence on external supply for radioisotopes used in nuclear medicine. In order to overcome this condition and due to the old age of these research reactors, the Brazilian Nuclear Energy Commission decided, in 2008, to construct a new research reactor. The new reactor named RMB (Brazilian Multipurpose Reactor) will be part of a new nuclear research center, to be built on a site about 100 kilometers from São Paulo city, in the southern part of Brazil. The new nuclear research center will have a 30 MW open pool type research reactor using low enriched uranium fuel, and several associated laboratories in order to produce radioisotopes for medical and industrial use, to use neutron beams in scientific and technological research; to perform neutron activation analysis; and to perform materials and fuels irradiation tests. Regarding the neutron beams use, the RMB design provides thermal and cold neutron beams. From one side of the reactor, the neutron guides will extend to an experimental hall of instruments named Neutron Guide Hall where it will be installed the scattering instruments. In the initial stage of the reactor operation, the intent is to implement two neutron guides for thermal neutrons and another two for cold neutrons. The 2015 SBPMAT symposium has presented the technical overview of the RMB project and its main buildings, structures and components. At this year symposium, the RMB presentation updates some technical information and the development status of the project, discussing the negative results of the Brazilian political and economic crisis to the project development and its future perspectives.

    Como referenciar este item
    Icon

  • IPEN-DOC 23388

    PEREIRA, VIVIANE S. ; SILVA, JULIO C.M. ; OLIVEIRA NETO, ALMIR ; SPINACE, ESTEVAM V. . Pt and PtRu nanoparticles supported on N-doped carbons as electrocatalysts for methanol electro-oxidation. In: BRAZILIAN MRS MEETING, 15th, September 25-29, 2016, Campinas, SP. Abstract... São Carlos, SP: Aptor Software, 2016. p. 1490-1490.

    Abstract: Methanol is a liquid transportation fuel that can be produced from fossil or renewable resources. Fuel cells employing methanol directly as fuel (Direct Methanol Fuel Cell – DMFC) are very attractive as power source for portable, mobile and stationary applications [1]. PtRu/C electrocatalyst has been considered the best electrocatalyst for methanol electro-oxidation, however, its performace is strongly dependent on the method of preparation and on the characteristics of the carbon support. N-doped carbons with different N contents (1, 2 and 5 wt%) were prepared by thermal treatment of carbon with urea at 800oC. Pt and PtRu nanoparticles were supported on N-doped carbons by coreduction of Pt(IV) and Ru(III) ions using an alcohol-reduction process [2]. The obtained materials were characterized by Energy Dispersive X-ray spectroscopy, X-ray diffraction, Transmission electron microscopy and Cyclic Voltammetry. Pt and PtRu nanoparticles supported on N-doped carbons showed superior performance for methanol electro-oxidation when compared to the materials supported on non-modified carbon and to Pt/C and PtRu/C commercial electrocatalysts. Pt/C and PtRu/C prepared with the carbon modified with 2.5 wt% of N content showed the best activities.

    Palavras-Chave: carbon; doped materials; electrocatalysts; heat treatments; methanol; nanoparticles; oxidation; platinum; ruthenium; transmission electron microscopy; voltametry; x-ray diffraction; x-ray spectroscopy

    Como referenciar este item
    Icon

  • IPEN-DOC 23387

    PEREIRA, CLOTILDE C. ; RODRIGUES JUNIOR, ORLANDO ; SILVA, LEONARDO G. de A. ; SANTIAGO, ELISABETE I. . Preparation and characterization of radiation-grafted poly(ethylene-co-tetrafluoroethylene) films as electrolyte for alkaline fuel cells. In: BRAZILIAN MRS MEETING, 15th, September 25-29, 2016, Campinas, SP. Abstract... São Carlos, SP: Aptor Software, 2016. p. 1583-1584.

    Abstract: Anion Exchange membranes (AEMs) are a promising alternative to the development of more efficient electrolytes for alkaline fuel cells. In general, the AEMs are ionomeric membranes able to conduct hydroxide ions (OH-) due to quaternary ammonium exchange groups, which confer to AEM high pH equivalent. The AEMs are based on crosslinked fluorinate/partially fluorinated polymer due to their outstanding chemical and thermal stability compared to hydrocarbon polymer-based matrix. The pre-irradiation method has been widely used for grafting (copolymerization) of monomers into polymer matrix due to a reduced formation of homopolymers and the possibility of grafting to be carried out at any time. The radicals produced during radiation process decay as a function of time and affect the grafting reaction, such as reduction of active centers, grafting yield and membranes properties. In order to optimize the irradiation parameters process and the membrane reproducibility, the stability of radicals styrene-grafted ETFE prepared by using electron beam irradiation by doses of 70 and 100 kGy as a function of storage time (up to 10 months) was evaluated by electron paramagnetic resonance (EPR), degree of grafting, ion exchange capacity (IEC), and electrochemical impedance spectroscopy. Results have shown that the radicals formed could be preserved by storage at low temperature (-70 °C), producing membranes with high homogeneity and satisfactory ionic conductivity. Such results have demonstrated that ETFE-based AEMs are promising electrolyte for alkaline fuel cell applications.

    Como referenciar este item
    Icon

  • IPEN-DOC 23386

    PAULA, VINICIUS G. de; REIS, DELCICLEIDE C. dos; SILVA, LUZELI M. da; SANTOS, ADENILSON O. dos; CARVALHO, ROSSANO L.; OTUBO, LARISSA ; COELHO, ADELINO de A.; CARDOSO, LISANDRO. Cristallite size tuning on magnetocaloric effect of ball milled HoAl2. In: BRAZILIAN MRS MEETING, 15th, September 25-29, 2016, Campinas, SP. Abstract... São Carlos, SP: Aptor Software, 2016. p. 1543-1544.

    Abstract: The magnetocaloric effect (MCE) is the basis for alternative, environment-friendly new refrigeration technologies. It is an intrinsic property of all magnetic materials, occurring as a consequence of the coupling among external applied field and the magnetic sub-lattice. [1] In this study, we report on the synthesis, microstructural and magnetic characterization of mechanically milled HoAl2 compound. The samples were investigated by using x-ray diffraction, scanning electron microscopy (SEM) and magnetization measurements. HoAl2 polycrystalline sample were submitted to a milling process using high energy ball mill in order to produce metallic nanoparticles. The bulk sample show single phase with cubic MgCu2- type structure. The lattice parameter was not significant changed by milling process up to 20 h of milling time. On the other hand, the crystallite size is strongly reduced reaching 28 nm for 20 h sample. Magnetic measurement show ferromagnetic phase transition around 32 K for bulk and all milled samples. A contribution related with spin reorientation is also observed below 20K, which becomes more pronounced as milling time increase. The magnetization of saturation reduces from 8.4 (bulk sample) to 6.2 μB/u.f. (20 h sample), due to the weakening of long-range magnetic ordering caused by size effects. The mechanical milling reduces the maximum values of magnetic entropy change (−DSM max) from 30 J/kgK (bulk sample) to 15 J/kgK (20 h milled sample). A significant broadening in the −DSM peak profile is observed as the milling time increase, which enhance in the full width half maximum (δTFWHM) of entropy change peak. High values of δTFWHM are associated with a large operation temperature range of magnetic refrigerator prototypes making the milled HoAl2 interesting for magnetic refrigeration purposes.

    Como referenciar este item
    Icon

  • IPEN-DOC 23385

    NASCIMENTO, MAURICIO S.; FRANCO, ANTONIO T.R.; NAKAMOTO, FRANCISCO Y.; FRAJUCA, CARLOS; SANTOS, GIVANILDO A. dos; COUTO, ANTONIO A. . Correlation between Microstructure and Mechanical Properties of Al-Si-Cu Alloys Casting. In: BRAZILIAN MRS MEETING, 15th, September 25-29, 2016, Campinas, SP. Abstract... São Carlos, SP: Aptor Software, 2016. p. 1058-1059.

    Abstract: It is well known that mechanical properties depend on solidification structures. The effects of microstructure on metallic alloys properties has been highlighted in various studies and particularly, the influence of grain size and dendrite arm spacing upon the mechanical properties has been reported [1-3]. The aim of this work is obtain correlations between microstructure and the mechanical properties of Al-10wt%Si-2wt%Cu and Al-10wt%Si-5wt%Cu alloys casting. These alloys were solidified under upward unsteady state heat flow conditions. Heat was directionally extracted only through a water-cooled bottom made of steel (SAE 1020). The results include tip growth rate (VL), cooling rate (TR), primary dendrite arm spacing (λ1), ultimate tensile strength (LRT) and yield strength (LE) as a function of solidification conditions imposed by the metal/mold system. In both cases (LRT and LE = 0.2%ε), the finer dendritic arrangement presents superior mechanical properties for the Al-Si-Cu alloys studied.

    Como referenciar este item
    Icon

  • IPEN-DOC 23384

    NASCIMENTO, MAURICIO S.; FRANCO, ANTONIO T.R.; NAKAMOTO, FRANCISCO Y.; FRAJUCA, CARLOS; SANTOS, GIVANILDO A. dos; COUTO, ANTONIO A. . An Experimental Study of the Influence of Solidification Thermal Variables upon Microstructure of Al-Si-Cu Alloys. In: BRAZILIAN MRS MEETING, 15th, September 25-29, 2016, Campinas, SP. Abstract... São Carlos, SP: Aptor Software, 2016. p. 1006-1006.

    Abstract: Solidification of metals involves the transformation of the molten metal back into the solid state. The transformation of a liquid into solid is probably the most important phase transformation in applications of science and engineering materials [1, 2]. Solidification structures impact heavily on the products final characteristics and therefore predict microstructure resulting from the solidification thermal variables is essential for the programming process using solidification. The aim of this work is obtain correlations between thermal solidification variables and the microstructure of Al-10wt%Si-2wt%Cu and Al-10wt%Si-5wt%Cu alloys. These alloys were solidified under upward unsteady state heat flow conditions. Heat was directionally extracted only through a watercooled bottom made of steel (SAE 1020). The results include tip growth rate (VL), cooling rate (TR) and primary dendrite arm spacing (λ1) as a function of solidification conditions imposed by the metal/mold system.For both alloys, it is found that the primary dendrite arm spacing decreases with the increase in tip growth rate and cooling rate.

    Como referenciar este item
    Icon

  • IPEN-DOC 23383

    MUCCILLO, REGINALDO ; MUCCILLO, ELIANA N. dos S. . Novel sintering approaches for densifying ceramic oxides with improved properties. In: BRAZILIAN MRS MEETING, 15th, September 25-29, 2016, Campinas, SP. Abstract... São Carlos, SP: Aptor Software, 2016. p. 1970-1970.

    Abstract: Ion conducting, semiconducting and superconducting oxides have been sintered to designed density and controlled grain size distribution by applying AC electric fields at temperatures lower than those used in conventional sintering. Temperature, electric field strength and frequency, electric current density threshold, number of electric current pulses, constant or pulsed delivered electric power, average particle size, particle size distribution, and green density are key factors to be considered for a successful fabrication of ceramic pieces with desired properties. Experiments have been carried out in fully and partially oxide ion conducting zirconia solid electrolytes, doped barium cerate and barium zirconate proton conductors, pure and doped semiconducting tin dioxide, in high- TC bismuth-based superconducting oxides, and in planar solid oxide fuel cells. Near to full density ceramic pellets have been produced with enhanced properties. Noteworthy is the possibility of densifying ceramic bodies to full density with controlled grain growth at considerably lower temperatures and in short times than in conventional sintering.

    Como referenciar este item
    Icon

  • IPEN-DOC 23382

    MORAES, LETICIA P. R. de ; MATOS, BRUNO R. ; SANTIAGO, ELISABETE I. ; FONSECA, FABIO C. ; AMICO, SANDRO C.; MALFATTI, CELIA de F.. Palladium-based Electrocatalysts for Ethanol Oxidation Reaction in Alkaline Direct Ethanol Fuel Cell. In: BRAZILIAN MRS MEETING, 15th, September 25-29, 2016, Campinas, SP. Abstract... São Carlos, SP: Aptor Software, 2016. p. 1566-1567.

    Abstract: Direct ethanol fuel cells require adequate electrocatalysts to promote the carboncarbon cleavage of ethanol molecule. Typical electrocatalysts are based on platinum, which have shown improved activity in acidic media. However, Pt-based catalysts have high cost and are easily deactivated by CO poisoning. Therefore, novel catalysts have been developed, and among then, palladium-based materials have shown promising results for the oxidation of ethanol in alkaline media. The present study reports on the performance of alkaline direct ethanol fuel cel (ADEFC) by using carbon-supported Pd, PdSn, PdNi, and PdNiSn produced by impregnation-reduction of the metallic precursors. The effect of chemical functionalization by acid treatment of the carbon support (Vulcan) was investigated. The electrocatalysts were studied by thermogravimetric analysis (TGA), X-rays diffraction (XRD), transmission electron microscopy (TEM), cyclic voltammetry (CV), and ADEFC tests. TGA measurements of functionalized Vulcan evidenced the characteristic weight losses attributed to the presence of surface functional groups due to the acid treatment. A high degree of alloying between Pd and Sn was inferred from XRD data, whereas in both PdNi and PdNiSn, Ni occurs mostly segregated in the oxide form. TEM analyses indicated agglomeration of Pd and PdSn particles, whereas a more uniform particle distribution was observed for PdNi and PdNiSn samples. CV curves showed that the peak potential for the oxidation of ethanol shifts towards negative values for all samples supported on functionalized Vulcan indicating that ethanol oxidation is facilitated. Microstructural and electrochemical features were confirmed by ADEFC tests, which revealed that the highest open circuit voltage and maximum power density were achieved for PdNiSn electrocatalysts supported on functionalized Vulcan with uniform particle distribution and improved triple phase boundaries.

    Palavras-Chave: carbon; direct ethanol fuel cells; electrocatalysts; ethanol; oxidation; palladium; thermal gravimetric analysis; transmission electron microscopy; voltametry; x-ray diffraction

    Como referenciar este item
    Icon

  • IPEN-DOC 23381

    LORENZO, CARLOS G.; WATANABE, SHIGUEO; GENNARI, ROSELI F.; BUENO, CARMEN C. ; CANO, NILO F.. Gamma and Neutron Detection of Un-doped and Doped (Eu, Dy, B) Calcium Silicate Polycrystal. In: BRAZILIAN MRS MEETING, 15th, September 25-29, 2016, Campinas, SP. Abstract... São Carlos, SP: Aptor Software, 2016. p. 771-771.

    Abstract: The use of different types of radiation is being increasingly widespread in various human activities such as in several industrial and nuclear technologies, where high radiation doses are involved, while in medicine usually low doses are involved. The radiation, on the other hand can be harmful to human being so that gamma and neutron radiation dosimetry becomes very important. There exist different detectors systems in radiation dosimetry but that based on the thermoluminescent crystals being one of the most important. For example, LiF based LiF:Mg,Ti (MTS) and LiF:Mg,Cu,P (MCP) that proved to be good detectors for gamma-rays, neutrons and other radiation [1]. On the other hand, natural silicate minerals proved to be very sensitive TL materials. In our laboratory several natural silicate minerals have been investigated, among them, the green quartz was proved to be very sensitive dosimeters both for low (mGy) and for high and very high radiation doses (kGy-Mgy) [2]. In this work, we produced in the laboratory polycrystals of CdSiO3 and CaSiO3. With respect to CaSiO3 we produced polycrystals doped with Eu, Dy, Cd and B. CaSiO3 doped or not has shown to be excellent detectors of gamma-rays as well as of neutrons produced in a research reactor (reactor IEA-R1 from Institute for Energy and Nuclear Research). CdSiO3 presented a TL peak at low temperature, therefore is unstable, while all CaSiO3 detectors have shown an excellent behavior.

    Como referenciar este item
    Icon

  • IPEN-DOC 23380

    LOBO, RAQUEL de M. ; DIAS, ALDISON D.F.; MARINUCCI, GERSON ; ANDRADE, ARNALDO H.P. de . Fractography and failure mechanisms in cfrp tubes submitted to burst testing. In: BRAZILIAN MRS MEETING, 15th, September 25-29, 2016, Campinas, SP. Abstract... São Carlos, SP: Aptor Software, 2016. p. 1938-1938.

    Abstract: The characterization of the failure mechanisms of CFRP components has been expanded as its demand for structural members in several applications increases.Composite tubular elements are used as biaxial structural components in applications where high mechanical performance per unit weight is a vital design requirement.In composite materials it is well known that the interface between fiber and matrix or interphases in those regions influences the overall composite properties.Crack propagation between plies (delamination) is the most commonly observed damage in CFRP since the fracture energy for cracking through the resin layer is lower than that for cracking through the fibers.Composite materials are known to display complex failure modes, typically involving multiple interacting damage processes, occurring over various length-scales. Fiber breaks occur in the micrometer range, whereas delaminations may occur over millimeter to meter scales, depending on the structure´s size and geometry.In recent years, quantitative fractography has become a method by which one can analyze the evolution of the interaction between crack and microstructure.Fracture morphology reveals that the dominant failure surface features were found to be fiber breakage, pull-out, and matrix cleavage and hackle formation resulting from interfacial tensile or shear failure.In the present work, specimens extracted from filament wound tubes subjected to burst test at room temperature were examined by optical and scanning electron microscopies in order to understand the failure mechanisms of such tubes.

    Como referenciar este item
    Icon

  • IPEN-DOC 23379

    LEITE, ANTONIO M. dos S. ; TERADA, MAYSA ; FONSECA, EDUARDO B. da; PEREIRA, VICTOR F.; COSTA, ISOLDA . Pitting corrosion resistance of friction stir welded lean duplex stainless steel UNS S82441 evaluated by cyclic potentiodynamic polarization and critical pitting temperature (CPT). In: BRAZILIAN MRS MEETING, 15th, September 25-29, 2016, Campinas, SP. Abstract... São Carlos, SP: Aptor Software, 2016. p. 1140-1141.

    Abstract: Duplex stainless steels have been widely used in the manufacture of equipment and piping for different segments, such as chemical, pulp & paper and oil & gas. The major limitation of these steels is the precipitation of deleterious phases whenever they are exposed to high temperatures. This fact drastically reduces the corrosion resistance and mechanical properties of these materials. The friction stir welding (FSW) has been considered an alternative to replace fusion welding processes. FSW is a solid state welding process avoiding many of the weldability problems associated to conventional fusion techniques. In this paper, the corrosion resistance of friction stir welded lean duplex grade 2404 (UNS S82441) was evaluated by cyclic potentiodynamic polarization and critical pitting temperature (CPT) in Cl- containing media . The results indicated that for the conditions adopted the FSW process did not have a significant effect on the pitting corrosion resistance of the steel studied.

    Palavras-Chave: stainless steels; friction welding; pitting corrosion; corrosion resistance; resistance welding; temperature range 0400-1000 k

    Como referenciar este item
    Icon

  • IPEN-DOC 23378

    GARCIA, FRANCISCO J.M.; PORRUA, AMANDA R.; COLLS, GISELLE F.; MOURA, ESPERIDIANA A.B. ; VALENZUELA, MARIA das G. da S.; MOLINER, TANIA R.; RIVERA, JOSE L.V.; DIAZ, FRANCISCO R.V.. Organic bentonites-HIPS nanocomposites. Influence of EB radiation on the mechanical properties. In: BRAZILIAN MRS MEETING, 15th, September 25-29, 2016, Campinas, SP. Abstract... São Carlos, SP: Aptor Software, 2016. p. 447-447.

    Abstract: In this paper the influence of additions of two clay types to form nanocomposite materials with high impact polystyrene as matrix, is discussed. Among the clays used as reinforcing material there are calcic Cuban and sodic Brazilian bentonites. The additions were made at two levels: 5 and 7% relative to the weight of the material. All clays used were subjected to organic modification. Composite material pellets were prepared in a hot extrusion process adding the clays with the aid of a vibrating dispenser. Mechanical tests samples, for tensile and impact tests according to ASTM standards, were elaborated in an injection molding machine. Another objective of this work was to study the effect of electron beam radiation in the mechanical properties of the nanocomposites. Half of the samples were irradiated at 600KGy and tested after a 7 days wait to ensure their stability. The rest of the specimens were tested from their direct injection state. It was shown that an addition of up to 5% of clay as reinforcement in a matrix of HIPS achieved increases in tensile strength over 30% compared with the unreinforced polymer. Additions of higher amounts of clay (7%) represented a decrease on mechanical strength, but remaining even above that of the pure polymer. Electron beam Irradiated samples showed a considerable increase in the mechanical strength with respect to the pure material. Increases between 48 and 56% in the tensile strength were achieved. In all cases, as it is expected elongation and impact strength decreased with the aforementioned increase in tensile strength.

    Como referenciar este item
    Icon

  • IPEN-DOC 23377

    FUJITA, ISAC K.; FABBRO, INACIO M. dall; GAZZOLA, JONATHAN; SILVA, GABRIELA K. e; SANTOS, GIVANILDO A. dos; NAKAMOTO, FRANCISCO Y.; COUTO, ANTONIO A. . Experimental application using shadow moiré technique in tensile test. In: BRAZILIAN MRS MEETING, 15th, September 25-29, 2016, Campinas, SP. Abstract... São Carlos, SP: Aptor Software, 2016. p. 1041-1041.

    Abstract: Non-destructive testing can determine the occurrence of failures individually material and among them are the optical methods that use optical interferometry and produce fringes to determine strain and stress rates of an object. The moiré techniques are based on the moiré phenomenology and characterized to be an effect resulting from the geometrical interference between two or more overlapping grids, generating patterns of lucid and dark lines which are denoted by moiré fringe patterns. The shadow moiré technique consists in designing a grid ahead of the object that serves as a reference grid. The shadow of the projected grid on the object generates a second grid, in this case works as a grid object and interacting with the reference grid to the formation of fringes. The experiment was consisted of submitting a standardized test piece to a strain test in universal testing machine and verify, through the shadow moiré technique, the behavior of the specimen surface. The different coloring in the treatment of the images, because it is a tensile test, can be associated with the distribution of stress and deformation along the specimen. Indeed, where there is greater concentration of tension is where the breakdown occurs, therefore it is suggested that the shadow moiré techniques in tensile test showed the region of greatest tension and subject to breakdown. The studies of plots showed the existence of relationship between the number of fringes and the information about the material. To explore this result would be necessary to capture the image at the time of a test and check the displacement of the fringes and, consequently, the distribution of stress and strain field. The continuity of this work may add innovations in the analysis of stresses and strains materials, thus contributing to other areas to take ownership of this methodology and use these methods to the development of knowledge and science.

    Como referenciar este item
    Icon

  • IPEN-DOC 23376

    FONSECA, DANIELA P.M. da ; MONTEIRO, WALDEMAR A. . Electrical conductivity and microstructural analysis of composite Cu-Ag-Cr-Al2O3 after sintering on powder metallurgy processing. In: BRAZILIAN MRS MEETING, 15th, September 25-29, 2016, Campinas, SP. Abstract... São Carlos, SP: Aptor Software, 2016. p. 1107-1107.

    Abstract: The aim of this work was to produce copper-chromium-silver alloys with alumina by powder metallurgy, forming a composite, keeping good mechanical (hardness test) and good electrical (electrical conductivity) properties. The elements are added to copper alloys with purpose to improve mechanical strength, ductility and thermal stability, without causing considerable damage in its shape, electrical and thermal conductivity. The metallic powders with alumina have been mixed for an appropriate time, compressed in uniaxial pressure and sintered at temperatures of 923K to 1073K in appropriate vacuum. The obtained alloys were characterized by electrical conductivity, optical microscopy, and Vickers hardness measurements. The steps performed in composites obtained by powder metallurgy processing indicate adequate mechanical resistance values (450 MPa) and, electrical conductivity in the range 0,216 ≤ σ ≤ 0,309 (μΩcm)-1 (35 to 45% IACS). Electrical conductivity measurements and analysis of microstructures by optical microscopy suggest that these composites are relevant to the application as electrical contact material used in consumer electronics devices.

    Como referenciar este item
    Icon

  • IPEN-DOC 23375

    FONSECA, FABIO C. ; MORAES, LETICIA P.R. de ; ESPOSITO, VINCENZO; FLORIO, DANIEL Z. de; MARANI, DEBORA. 2D layered gadolinium-doped cerium oxide nanomaterials. In: BRAZILIAN MRS MEETING, 15th, September 25-29, 2016, Campinas, SP. Abstract... São Carlos, SP: Aptor Software, 2016. p. 656-656.

    Abstract: The exceptional properties arising from versatility in composition, morphology, and structure, two-dimensional (2D) layered nanomaterials have attracted huge interest in the last decade. Such materials, consisting in stacked charged nanosheets intercalated with opposite charged exchangeable anions, are of great potential for the design and fabrication of nanostructures in many applications. The interlayer gallery provides a flexible space to accommodate various sized molecules (e.g. pollutants) and tune specific active sites at the atomic space (e.g. catalyst materials). The interest for 2D layered nanomaterials is also associated with the possibility of obtaining via exfoliation ultra-thin nanosheets with lateral dimensions of hundreds of nanometres and thickness of few nanometres. This unique class of nanomaterials has shown many unprecedented properties mainly originating from the dimensional anisotropy and nano-confinement effects. Herein we propose novel 2D layered ceria based oxides (e.g. CGO) synthesized via the heterogeneous precipitation. CGO materials were selected because of their strategic relevance in many technological applications (e. g. catalysis and electrochemical devices). The synthesized CGO layered materials were characterized for their composition, morphology and crystallographic features. The combined experimental results indicated that the layered CGO, with tunable dopant concentration, can be obtained in different morphologies by controlling the synthesis parameters.

    Como referenciar este item
    Icon

  • IPEN-DOC 23374

    CARVALHO, SABRINA G. de M. ; MUCCILLO, ELIANA N. dos S. ; MUCCILLO, REGINALDO . Electric field-assisted sintering of yttria-stabilized zirconia: dependence on the frequency and the current density. In: BRAZILIAN MRS MEETING, 15th, September 25-29, 2016, Campinas, SP. Abstract... São Carlos, SP: Aptor Software, 2016. p. 71-71.

    Abstract: ZrO2:3 mol% Y2O3 green pellets were sintered by applying AC electric fields (0.5-1.1 MHz, 100/200 V.cm-1, 20-120 mA.mm2) at T<1200oC (first stage sintering). Similar specimens reached shrinkage levels dependent on the frequency of the applied field, suggesting that the Joule heating imparted to the specimen depends on the number of collisions of charge carriers with chemical species at the intergranular region. Moreover, under similar experimental conditions, the shrinkage level increases for increasing electric current density, up to a limit close to full shrinkage. Electrochemical impedance spectroscopy experiments were carried out in the ionic domain in flash sintered specimens. The Arrhenius plots of bulk and grain boundary contributions are evidence that for increasing electric current density the bulk conductivity is the same, but the grain boundary conductivity increases. It is proposed that the preferential paths for the electric current through the sample are the interfaces, mainly grain boundaries and pores. Moreover, the results give additional evidence for densification upon sintering without significant grain growth under electric field-assisted sintering.

    Como referenciar este item
    Icon

  • IPEN-DOC 23373

    AMARANTE, MAYARA dos S.; XAVIER, ROSANA S.; LENTE, MANUEL H.; GENOVA, LUIS A. ; BRITO, VERA L.O. de. Sintering study of ferrites, BaTiO3 and their ceramic composites. In: BRAZILIAN MRS MEETING, 15th, September 25-29, 2016, Campinas, SP. Abstract... São Carlos, SP: Aptor Software, 2016. p. 732-732.

    Abstract: Traditional solid-state sintering studies of cobalt ferrite are extremely rare in the literature [1]. Differences in thermal coefficients and ultimately lead to delamination, micro-cracking or pore formation in the ceramic materials. Phase changes as a result of sintering (e.g. tetragonal to cubic in BaTiO3) can also contribute to sintering mismatch [2]. Cobalt ferrite and nickel cobalt ferrite powders were prepared using solid-state ceramic processing. Calcination of the ferrite powders was carried out with a heating rate of 5°C/min up to 1050°C and 240 min hold at 1050°C. The calcined powders were uniaxially pressed in the shape of Rectangular bars (20mm X 5mm X 4mm) and cold iso-statically pressed for use as samples for dilatometric thermal analysis. The dilatometry tests of the ferrites, the BaTiO3 (TB), and ferrtite-TB samples were carried out, some samples with constant heating rate and some samples simulating sintering with 2h hold time at a certain temperature. Based on the dilatometry results, sintering thermal cycles for both ferrites and TB were proposed. The microstructure of the sintered samples was evaluated by scanning electron microscopy and their densities were measured by the Archimedes’ method. The results were discussed relating the density and grain size of the samples to the sintering parameters. The same was done with nickel cobalt ferrite and TB to obtain the composite. The sintering study were did to devise a maximum theoretical density of >90%.

    Como referenciar este item
    Icon

  • IPEN-DOC 23310

    ANDRE-FILHO, J.; COAQUIRA, J.A.H.; MESTNIK-FILHO, J. ; CARBONARI, A.W. ; NAGAMINE, L.C.C.M.. Hydrogen absorption effects on the physical properties of ball-milled LaNiSn intermetallic compounds. In: TEMST, KRISTIAAN (Ed.); VANTOMME, ANDRE (Ed.); COTTENIER, STEFAAN (Ed.); PEREIRA, LINO (Ed.) INTERNATIONAL CONFERENCE ON HYPERFINE INTERACTIONS AND THEIR APPLICATIONS, July 3-8, 2016, Leuven, Belgium. Abstract... Leuven, Belgium: Instituut voor Kern- en Stralingsfysica, 2016.

    Abstract: A polycrystalline samples were prepared by arc melting high-purity elements under argon atmosphere. The samples were re-melted several times to ensure homogeneity. After arc-melting, the samples were annealed in vacuum at 800°C for 28h. After that, some samples were milled using a Ball milling technique. The hydrogenation was carried out by the Sievert’s method using a high purity hydrogen gas. X-ray diffraction (XRD) measurements indicate the formation of the TiNiSi-type orthorhombic structure with space group Pnma for the unmilled sample and its hydride. The milled samples show broad peaks and poor crystallinity hindering the analysis of the structural properties. One sample was milled with 10wt% of graphite. The analysis of the graphite-milled sample reveals that graphite preserves the structural properties (the sample shows better crystalline quality) and acts as a catalyst for the absorption of hydrogen. The analyses of the XRD patterns show that the structural parameters are modified after the hydrogenation. The transmission electron microscope images corroborate the XRD data. Mössbauer spectra (297K) of the unmilled LaNiSn show the presence of only one doublet inconsistency with the one symmetry site of Sn atoms in the TiNiSn-type structure. Moreover, spectra of the milled samples are better reproduced by considering three doublets. Those components were associated with Sn atoms occupying regular sites (D1), Sn atoms substituting Ni atoms (D2) and Sn atoms of some spurious phase or Sn atoms localized in the interface region of the grains (D3). The spectral area of the D1 component decreases at expenses of the other two components. However, the isomeric shift (IS) of D1 and D2 shows a constant value as the milling time is increased. The IS of the third doublet shows some fluctuating behavior likely related to its small spectral area. The quadrupole splitting (QS) of D2 component shows larger value than that of the D1 component and both show clear increasing tendency as the milling time is increased. After the hydrogenation, the IS shows an increase related to the samples before hydrogenation. However, the IS of the D1 and D2 components do not undergo a drastic change in value with the milling time. The value of the QS of D1 and D2 components show an increase with the milling time. This result has been assigned to the indirect interaction between Sn and H atoms which causes an asymmetric electron distribution around the Sn atoms.

    Como referenciar este item
    Icon

  • IPEN-DOC 23309

    KRYLOV, V.I. ; BOSCH-SANTOS, B. ; CABRERA-PASCA, G.A. ; CARBONARI, A.W. ; SAXENA, R.N. ; MESTNIK-FILHO, J. . Temperature anomalies of the hyperfine magnetic fields on 111Cd probe nuclei in ferro- and antiferromagnetic phases of the ordered FeRh alloys. In: TEMST, KRISTIAAN (Ed.); VANTOMME, ANDRE (Ed.); COTTENIER, STEFAAN (Ed.); PEREIRA, LINO (Ed.) INTERNATIONAL CONFERENCE ON HYPERFINE INTERACTIONS AND THEIR APPLICATIONS, July 3-8, 2016, Leuven, Belgium. Abstract... Leuven, Belgium: Instituut voor Kern- en Stralingsfysica, 2016.

    Abstract: FeRh ordered alloy crystallizes in the bcc B2 structure [1], presents first order phase transition from antiferromagnetic (AF) ordering at low temperature to ferromagnetic (F) state above 350 K [2], and shows significant magnetocaloric effect near RT [3]. Recently, FeRh alloy has also been considered as an interesting material for spintronics applications [4]. In the AF state, FeRh has compensated AFII-type magnetic structure with μFe=3.3 μB and μRh=0. In the F state of FeRh both Fe and Rh atoms have magnetic moments of μFe=3.2 μB and μRh=0.9 μB, respectively [5]. The Fe – Rh compounds were studied by Mössbauer spectroscopy (MS) on 57Fe [6, 7] and 119Sn probe nuclei [8]. In this work, we have, for the first time, investigated the HFs for 111Cd probe atoms in two FeRh samples of different composition by perturbed γ-γ angular correlation (PAC) spectroscopy in the range from 40 K to a temperature above the TC. The alloy Fe0.48Rh0.52 (A1 sample) is AF at low temperatures. At the temperature Tt = 345 K the first order phase transition is observed, and this compound becomes F at the temperatures lower than TC = 685 K. The alloy Fe0.52Rh0.48 (A2 sample) is only ferromagnetic below TC = 800 K. It was established that in both alloys 111Cd probes substitute only Fe ions. The HFs values extrapolated to 0 K were found to be B1(0) =8.70(5) T and B2(0) =5.53(5) T for AF and F ordering of A1 and A2 samples, respectively. The HF in the AF state is almost 60% higher than the HF in the F alloy. The dependences B1 (T) and B2 (T) show anomalous behavior. At Tt = 345 K, phase transition AF-F is accompanied by a sharp decrease in the HF at 111Cd probe nuclei. Earlier, an increase of the corresponding HFs was observed for 57Fe atoms and 119Sn impurity atoms in the region of AF-F transition by MS in [6] and [8]. Analysis of B1(T) and B2(T) has allowed to obtain the temperature dependences of the competing contributions BFe (T) and BRh (T) to the HFs on 111Cd probe nuclei in FeRh alloys.

    Como referenciar este item
    Icon

  • IPEN-DOC 23308

    KRYLOV, VASILY I. ; BOSCH-SANTOS, BRIANNA ; CABRERA-PASCA, GABRIEL A. ; CARBONARI, ARTUR W. . Huge negative magnetic hyperfine fields for 111Cd probe nuclei in the Fe3X (X=C, Ge, and Ga) compounds with specific properties. In: TEMST, KRISTIAAN (Ed.); VANTOMME, ANDRE (Ed.); COTTENIER, STEFAAN (Ed.); PEREIRA, LINO (Ed.) INTERNATIONAL CONFERENCE ON HYPERFINE INTERACTIONS AND THEIR APPLICATIONS, July 3-8, 2016, Leuven, Belgium. Abstract... Leuven, Belgium: Instituut voor Kern- en Stralingsfysica, 2016.

    Abstract: In recent years, Fe3X (X = C, Ga, and Ge) alloys are actively investigated experimental and theoretical methods due to their potential practical use as invar, magnetostrictive materials, and multi-layered ferromagnetic film [1-3]. The Fe3C alloy was studied by nuclear resonant scattering on 57Fe and by x-ray emission spectroscopy at high pressure up to 50 GPa because this substance could be the major Earth’s inner core component [4, 5]. In this work we found huge negative HFs reaching a magnitude of Bhf = -46T on 111Cd probe nuclei in ferromagnetic Fe3X (X = C, Ga, and Ge) alloys by perturbed γ-γ angular correlation (PAC) spectroscopy. These values are the highest known HFs on 111Cd nuclei in metallic magnets. It was established that in Fe3C crystallizing in the orthorhombic DO11 structure (Pnma space group) 111Cd probes are placed in Feg sites with 11Fe atoms as nearest neighbours (n.n.). For Feg positions, the n.n. arrangement is similar to normal hexagonal close packing. The HF value for 111Cd atoms in Fe3C is equal to Bhf = -38.0(1) T at 77K. In tetragonal DO3 crystal structure of Fe3Ga 111Cd probes are placed in both Ga sites (12 n.n. Fe) and in FeII (8n.n.Fe). The HFs for 111Cd atoms in Fe3Ga are equal to Bhf = -39.8(1) T and Bhf = -24.2(3) T at 77K for Ga and FeII sites of 111Cd localization. In hexagonal DO19 crystal structure of Fe3Ge 111Cd probes are placed in Ge sites (12 n.n.). The HF value for 111Cd probes in Fe3Ge is equal to Bhf = -46.0(1) T at 40K. There are no any anomalies of the Bhf (T) on 111Cd nuclei in the spin reorientation region of Fe3Ge. The results of this work are analyzed with the previously obtained HF’s values on 111Cd nuclei in 3d metals and their alloys including Heusler alloys.

    Como referenciar este item
    Icon

  • IPEN-DOC 23307

    SILVA, ANDREIA ; AMARAL, ANTONIO ; LAPOLLI, ANDRE ; SAXENA, RAJENDRA ; CARBONARI, ARTUR . Investigation of hyperfine interactions in immunoglobulin G with perturbed angular correlation spectroscopy using 111Cd. In: TEMST, KRISTIAAN (Ed.); VANTOMME, ANDRE (Ed.); COTTENIER, STEFAAN (Ed.); PEREIRA, LINO (Ed.) INTERNATIONAL CONFERENCE ON HYPERFINE INTERACTIONS AND THEIR APPLICATIONS, July 3-8, 2016, Leuven, Belgium. Abstract... Leuven, Belgium: Instituut voor Kern- en Stralingsfysica, 2016.

    Abstract: Hyperfine interaction parameters have been used to investigate physical properties of biomolecules from different isotypes of immunoglobulins G (IgG1, IgG2a and IgG2b). Immunoglobulin IgG1 induces a pattern of response type Th2 that corresponds to an allergic immunological response, whereas immunoglobulin IgG2 induces a pattern of response Th1 that corresponds to a cellular immunological response, suited for response against parasites. Hyperfine interactions were measured by perturbed gamma-gamma angular correlation (PAC) spectroscopy using 111In(111Cd) and 111mCd(111Cd) as probe nuclei. The measurements were carried out for both the complete and fragmented molecules at 295 K and 77 K, and both static as well as dynamic interactions were observed. Results of both measurements were used to calculate the rotational correlation time for each studied molecule. The complete and fragmented molecules showed different dynamic interactions. It was therefore conclude that the PAC technique is quite adequate for differentiating between the isotypes of immunoglobulins as well as their dynamic behavior if adequate nuclear probe is utilized with rigorous control of measuring conditions. The hyperfine parameters obtained are related to the physical properties of each molecule in an attempt to understand the difference in their biological function.

    Como referenciar este item
    Icon

  • IPEN-DOC 23306

    SALES, TATIANE ; CAVALCANTE, FABIO ; CABRERA-PASCA, GABRIEL ; PEREIRA, LUCIANO F. ; SAXENA, RAJENDRA ; CARBONARI, ARTUR . Investigation of Rare Earth (RE = La, Dy, and Er) doping of HfO2 by perturbed angular correlation spectroscopy. In: TEMST, KRISTIAAN (Ed.); VANTOMME, ANDRE (Ed.); COTTENIER, STEFAAN (Ed.); PEREIRA, LINO (Ed.) INTERNATIONAL CONFERENCE ON HYPERFINE INTERACTIONS AND THEIR APPLICATIONS, July 3-8, 2016, Leuven, Belgium. Abstract... Leuven, Belgium: Instituut voor Kern- en Stralingsfysica, 2016.

    Abstract: The hyperfine interactions at 181Hf(181Ta) probe nuclei in HfO2 samples doped with 5% rare-earth (RE = La, Dy, and Er) elements were measured by perturbed angular correlation (PAC) spectroscopy. Hafnium dioxide has been extensively studied as a potential alternative to silicon dioxide as dielectric gate material in the silicon based complementary-metal-oxide-semiconductors (CMOS) technology due to its high dielectric constant and relatively high thermal stability with respect to silicon. The addition of RE to HfO2 can suppress oxygen vacancies and promote a change in the crystal structure increasing the dielectric permitivity. Samples were prepared using the sol-gel chemical method, starting from very pure metals. The resulting powder of each sample was annealed in air at 550 o C for 12 h. The crystal structures of samples were checked by X-ray diffraction. Result revealed only a single phase corresponding to the monoclinic phase P 21/C of HfO2 for all samples. PAC spectra measured at room temperature were fitted with two electric quadrupole interactions with different environments for all samples including a pure HfO2. The major components (70-75%) were characterized by quadrupole frequencies 𝜈𝑄 ∼ 790 MHz with a distribution around 6% and asymmetry parameter 𝜂 = 0.34 for Dy- and Er-doped samples. La-doped sample showed a slightly lower frequency (𝜈𝑄 = 727 MHz) with larger asymmetry parameter (𝜂 = 0.43) for the major component. The major components are ascribed to probe nuclei at regular monoclinic sites of HfO2. The quadrupole frequency 𝜈𝑄 and asymmetry parameter 𝜂 for Dy- and Er-doped samples agree well with those values reported in the literature [1]. The minor components were characterized by 𝜈𝑄 ∼ 760 MHz with a distribution around 8% and asymmetry parameter 𝜂 = 0.75 for Dy- and Er-doped samples and 𝜈𝑄 = 783 MHz and 𝜂 = 0.61 for La-doped HfO2. These values are quite different from those reported for pure sample [1], assigned to probe nuclei near defects, and probably they are due to probe nuclei close to RE dopants, which reduce the presence of defects.

    Como referenciar este item
    Icon

  • IPEN-DOC 23305

    DOMIENIKAN, CLAUDIO ; BOSCH-SANTOS, BRIANNA ; PASCA, GABRIEL A.C. ; SAXENA, RAJENDRA ; CARBONARI, ARTUR . Hyperfine field at La in the intermetallic compound LaMnSi2 measured by PAC using 140Ce nuclear probe. In: TEMST, KRISTIAAN (Ed.); VANTOMME, ANDRE (Ed.); COTTENIER, STEFAAN (Ed.); PEREIRA, LINO (Ed.) INTERNATIONAL CONFERENCE ON HYPERFINE INTERACTIONS AND THEIR APPLICATIONS, July 3-8, 2016, Leuven, Belgium. Abstract... Leuven, Belgium: Instituut voor Kern- en Stralingsfysica, 2016.

    Abstract: Magnetic hyperfine field has been measured in the orthorhombic intermetallic compound LaMnSi2 with PAC spectroscopy using radioactive 140La-140Ce nuclear probes. Magnetization measurement was also carried out in this compound with MPSM-SQUID magnetometer. The LaMnSi2 sample was prepared by melting pure metallic components in stoichiometric proportions in an arc furnace under argon atmosphere. After melting, the sample was annealed at 1000 o C for 60h under helium atmosphere and then quenched in to water. X-ray analysis confirmed the sample to be in a single phase with correct crystal structure expected for LaMnSi2. The radioactive nuclei, 140La (T1/2 = 40h) were produced by direct irradiation of the sample with neutrons in the IEA-R1 nuclear research reactor at IPEN with a flux of ~1013 ncm-2s-1 for about 3-4 min. The irradiated sample was annealed at 1000 o C under helium atmosphere for 24 hours before starting the PAC measurement in order to minimize the effects of eventual radiation damage by fast neutrons during irradiation as well as to allow the decay of the short lived 56Mn (T1/2 = 2.6h) activity also produced in the sample. The PAC measurements were carried out with a six BaF2 detector spectrometer at several temperatures between 10 K and 400 K. The results showed well defined magnetic dipole interaction at all temperatures. Temperature dependence of the hyperfine field, Bhf was found to be anomalous. The magnetization measurement however, showed no anomaly. Therefore, the anomalous behavior of Bhf may be attributed to the interaction where 1f electron of the dilute Ce atom is spin polarized by the magnetic field from Mn sublattice and contributes to the effective hyperfine field. The ferromagnetic transition temperature (TC) of LaMnSi2 was determined to be 400(1) K confirming by magnetic measurement and the earlier results.

    Como referenciar este item
    Icon

  • IPEN-DOC 23301

    SILVA, ERIC B. da ; CORREIA, JOAO G.; ZOGHBY, MICHEL; GAHL, JOHN; SCHELL, JULIANA; MATOS, IZABELA T. de ; RIBEIRO JUNIOR, IBERE S. ; CARBONARI, ARTUR W. ; HUBLER, GRAHAM K.; VIOLANTE, VITTORIO; THIOYE, MOUSTAPHA; HE, JINGHAO. Hyperfine interactions in Pd foils during D/H electrochemical loading. In: TEMST, KRISTIAAN (Ed.); VANTOMME, ANDRE (Ed.); COTTENIER, STEFAAN (Ed.); PEREIRA, LINO (Ed.) INTERNATIONAL CONFERENCE ON HYPERFINE INTERACTIONS AND THEIR APPLICATIONS, July 3-8, 2016, Leuven, Belgium. Abstract... Leuven, Belgium: Instituut voor Kern- en Stralingsfysica, 2016.

    Abstract: The Fleischmann and Pons Effect (FPE) is the appearance of anomalous excess heat during electrolytic loading of hydrogen in metal. Although observed well above measurement uncertainties [1] this effect still remains unexplained. Unlike previous studies where hydrogen (H) was pre-loaded before Time Differential Perturbed Angular Correlations (TDPAC) [2,3] was performed, this present work probes, at the nanoscopic scale, palladium (Pd) samples during H and deuterium (D) loading in 0.1M LiOH or LiOD electrolyte. Radioactive 181Hf (181Ta) was implanted at 80 keV (HISKP-Bonn) and experiments were performed at the ISOLDE-CERN SSP laboratories after vacuum annealing to recover implantation defects. An almost “flat” unperturbed PAC – R(t) spectrum was observed, as expected for Hf/Ta atoms at cubic Pd sites with no remaining point defects in their vicinity. Upon D loading the “flat” unperturbed R(t) spectrum changes to a characteristic Gaussian-like EFG distribution, centered near zero EFG, due to the random distribution of D atoms inside the Pd lattice. With increasing D concentration, the central value of the distribution becomes nonzero, thus revealing that the Pd crystalline structure is relaxed from cubic, consistent with the phase diagram for Pd hydrides. The data also shows that, while being an impurity in the system under study, the Hf/Ta atoms do not trap nor significantly interfere with the H/D atoms in the Pd lattice that would bias the present studies. Thus, further experiments aimed at studying the FPE under external excitations are envisaged.

    Como referenciar este item
    Icon

  • IPEN-DOC 23292

    SANTOS, P.A.A.; SAKAGAMI, Y.; HAAS, R.; PASSOS, J.C.; TAVES, F.F.; NASSIF, F.; MOREIRA, A.; MOREIRA, G.A. ; MARQUES, M.T.A. ; BEU, C. ; LANDULFO, E. . Atmospheric stability using Doppler Wind Lidar profiler: a Case Study in Florianópolis Island. In: WORKSHOP ON LIDAR MEASUREMENTS IN LATIN AMERICA, 9th, July 17-22, 2016, Santos, SP. Abstract... 2016.

    Abstract: The effects of atmospheric stability can be important for many wind energy applications. This work aims to investigate the atmospheric stability using two Doppler wind lidar profilers based on a simple method that analyses how the wind shear variates with height. The experiment was carried on Florianopolis Island, located in the south coast of Brazil. The dataset covered a period from December 2014 to February 2015. The Windcube08 lidar has a range from 40m to 500m and the Windcube70 lidar was setup to range from 100m to 1000m. Both lidars recorded a 10min average wind speed with a vertical resolution of 20m. In addition, a 3D sonic anemometer measured turbulent fluxes at 20Hz. The method evaluated the variation of wind shear with height and was associated with the stability classes based on Obukhov Length. The wind speed of the two lidars was compared at 100m, 200m, 300m, 400m and 500m. This comparison showed an excellent agreement, with values better than R2=0.996 and RMSE=0.15 m/s. The results of wind profile indicated an unique condition at night, where were consistently observed convective wind profiles from 40m to 120m and stratified flow above 120m. Then, the presented method was adjusted to consider wind profile heights from 120m to 300m. The analysis of the atmospheric stability also presented a good agreement when comparing both lidars. The Very stable, stable and near stable conditions represented 41,2% (Windcube08) and 27,6% (Windcube70). On the other hand, the unstable condition was dominated by a very unstable condition with 21% and 38,7%, respectively. The neutral condition was the most frequent with 36,8% and 32,2%, respectively. The results of atmospheric stability classes diverged between the two lidars from 5h to 10h UTC, because of differences on wind speed average of around -0.8 m/s from 100m to 200m. In conclusion, the site presented specific conditions, which showed the challenges to propose an universal method to estimate the atmospheric stability using only doppler wind lidar data. However, the method achieved good agreement when comparing the wind profile with the atmospheric stability classes.

    Como referenciar este item
    Icon

  • IPEN-DOC 23291

    BEU, CASSIA M.L. ; MARQUES, MARCIA T.A. ; LANDULFO, EDUARDO . Nocturnal jet observational study over Sao Paulo city with wind Lidar. In: WORKSHOP ON LIDAR MEASUREMENTS IN LATIN AMERICA, 9th, July 17-22, 2016, Santos, SP. Abstract... 2016.

    Abstract: Sao Paulo is the biggest city of a dense Metropolitan Region with more 38 municipalities. The statistic government agency (IBGE) estimates that more than 20 million of inhabitants live in the Metropolitan Area. Just for Sao Paulo City, the population is more than 11 million of inhabitants and 7 million vehicles, in according to Detran (the traffic agency). Such density is a challenge for managing the quality air control and several studies have been carried out to understand the pollution dispersion over Sao Paulo Metropolitan Region (SPMR). Lapat (a Sao Paulo University team that studies pollution) have been developed important researches in this topic and some results are available in its site (http://www.lapat.iag.usp.br/index.html). One important result is that car emissions have high impact over the atmospheric pollution. Although that and others initiatives, many questions remain unanswered and the observational aspects represents a huge barrier as have been highlighted in several works. The data absence in the PBL (Planetary Boundary Layer) over SPMR was emphasized in a recent work dealing with LES modelling of the Nocturnal Jet (NJ). Therefore, the PBL observational features are an important contribution to research development of SPRM pollution dispersion field. In this sense, this work presents some aspects of the NJ observed over Sao Paulo City with a wind lidar for three months period (December-2015, January-2016 and February-2016) and expect to contribute to SPMR dispersion researches.

    Como referenciar este item
    Icon

  • IPEN-DOC 23290

    CORREA, THAIS ; LANDULFO, EDUARDO . Monitoring the environmental impact of grain storage in the region Port of Santos by the technical LIDAR. In: WORKSHOP ON LIDAR MEASUREMENTS IN LATIN AMERICA, 9th, July 17-22, 2016, Santos, SP. Abstract... 2016.

    Abstract: The presence of particulate matter can alter the atmosphere significantly, these particles may have variable composition, and various organic and inorganic compounds, which reflects the different training modes of interaction thereof with the atmosphere and the particle lifetime in medium. The interaction of this material with the environment can have a big impact on the hydrological cycle of a given region, and the health of the resident population in the area. Brazil is a world leader in the production of grains, especially soybeans and corn. The city of Santos SP is home to the largest port in Latin America, through which all national grain production to be exported to the world. The city of Santos has constant monitoring of air quality where it detects the presence of several pollutants, including particulate matter, but only quantifies their presence. This project aims to monitor the presence of particulate material from the storage and transportation of grains in the port area of the city of Santos - SP, quantifying and assessing the impacts caused by it, analyzing its composition for possible generating sources, its form of dispersion and interaction with the environment, using the lidar technique In this project will be used a portable biaxial and articulated developed by Raymetrics Systems. The this LIDAR transmission system works with a laser commercial pulsed Nd: YAG laser, operating at wavelengths of 1054, 532 and 355 nm, and the pulse energy of 120 mJ at a rate of laser repetition of 20 Hz and the pulse width is 20 ns, giving the system a spatial resolution of 3.75 m. This equipment will be transported and operated into the storage area of grain, enabling real-time monitoring of generated plumes.

    Como referenciar este item
    Icon

  • IPEN-DOC 23289

    MORAES, ANA P.F. ; LANDULFO, EDUARDO ; LOPES, FABIO J. da S. ; ANDRADE, MARIA de F.. Atmospheric Profile of Porto Nacional-TO in the burning season and correlation with respiratory diseases. In: WORKSHOP ON LIDAR MEASUREMENTS IN LATIN AMERICA, 9th, July 17-22, 2016, Santos, SP. Abstract... 2016.

    Abstract: The advance of brazilian agricultural frontier to North, reaching the State of Tocantins, brought the economic development to the region, but also the environmental impact. Burnings are very used to clean the cerrado (brazillian savanna) files. This procedure increased, becoming visible and making people complain about health as the smoke interfers in the local athmosphere. The literature reports the influence of aerosols in the people health at other places for a long time ago. It can’t be find this kind of investigation in the Tocantins’ cerrado. As the lidar is a tool of inquestionable importance for the athmospheric analises, it’s indispensable its utilization to feature the burning impact on cerrado’s athmosphere. Porto Nacional, a city distant 55 quilometers from the capital Palmas, was studied because it’s included in the agricultural frontier. The city has also been growing due to the university implantation, including the medicine college, attracting students and researchers. Thus, the factors listed above stimulated this interdisciplinary master science work, adding to the study of athmosphere profile, the attemptive to co-relate the burnings to the admissions for respiratory diseases in the city’s hospital, using the agreement between ITPAC-Porto and IPEN-USP.

    Como referenciar este item
    Icon

  • IPEN-DOC 23288

    MOREIRA, G. de A. ; GUERRERO-RASCADO, J.L.; BENAVENT-OLTRA, J.A.; ORTIZ-AMEZCUA, P.; LANDULFO, E. ; ALADOS-ARBOLEDAS, L.. Analyzing the turbulent structure of the Planetary Boundary Layer by Elastic lidar. In: WORKSHOP ON LIDAR MEASUREMENTS IN LATIN AMERICA, 9th, July 17-22, 2016, Santos, SP. Abstract... 2016.

    Abstract: The part of troposphere in direct contact with Earth’s surface is known as planetary boundary layer (PBL). This region, endowed with turbulent behavior, is the main responsible for the exchange of momentum and energy between the atmosphere and surface. These characteristics make the understanding of PBL structure important for a wide set of studies, which vary from weather forecasting to pollutant dispersion. However, this layer has a great variability throughout the day, and the classical instruments used to study it has temporal limitation (radiosoundings) or spatial limitation (anemometric and eddy covariance towers). Under this scenario, lidar systems have been fairly applied in the last decade due to the absence of such kind constraints. In this study, we used an elastic lidar to analyze the turbulent behavior of PBL and its internal processes. VELETA, a Raman lidar (Raymetrics Inc) operating at 355 and 387 nm with 1-s temporal and 7.5-m spatial resolutions, held the data acquisition. This system, located at IISTA-CEAMA (Andalusian Institute for Earth System Research) in Granada – Spain, is part of EARLINET (European Aerosol Research Lidar Network).We obtained the value of 1-h averaged atmospheric transmittance, T(r),and from it 1-s backscatter profiles, β(r), are derived. These values of β(r) were used to estimate the high order statistics moments (variance, skewness and kurtosis) and energy spectrum. This study enabled us to carry out a detailed description of PBL and it confirms the feasibility of elastic lidar signals for the characterization of the PBL turbulence as evidenced by other more sophisticated techniques such as high spectral resolution lidars (McNicholas, 2014) and rotational Raman lidars (Behrendt, 2015). In the near future we will apply the same methodology to a Doppler lidar and we will also study aerosol fluxes from the synergy of Doppler and elastic lidars.

    Como referenciar este item
    Icon

  • IPEN-DOC 23287

    MOREIRA, G.A. ; GUERRERO-RASCADO, J.L.; BENAVENT-OLTRA, J.A.; ORTIZ-AMEZCUA, P.; LANDULFO, E. ; ALADOS-ARBOLEDAS, L.. A comparison among statistical and classical methods to obtain the planetary boundary layer height by lidar data. In: WORKSHOP ON LIDAR MEASUREMENTS IN LATIN AMERICA, 9th, July 17-22, 2016, Santos, SP. Abstract... 2016.

    Abstract: The planetary boundary layer (PBL) is the lowermost part of the troposphere, which is characterized by large variability in its statical stability and turbulence along the day. This varying behavior makes the PBL height determination a key for a wide set of studies, including pollutant dispersion and weather forecasting. Due to its variability throughout the day, PBL monitoring requires instrumentation with high temporal and spatial resolution. During the last two decades lidar (light detect and ranging) systems have been largely applied to this kind of study. However, the PBLH discrimination by lidar is not straightforward, because algorithms are necessary to interpret the experimental data and remove ambiguities in layer attribution. Nevertheless, under situations of high atmospheric complexity, the algorithms might misunderstand PBLH top with other sublayers. In this study, we will compare the classical methods (Variance, Gradient and Wavelet Covariance Transform) with a statistical method based on Kalman filter, in an attempt to evaluate the strengths and weakness of each one. The measurements were recorded in the city of Granada – Spain during 2015 with the Raman lidar VELETA (Raymetrics Inc), operating at 355 and 387 nm with 1-min and 7.5-m resolutions. All methods were validated by Bulk Richardson Number obtained from simultaneous, collocated radiosounding data. This study will give us background for further improvements of the algorithms used in order to solve the difficulties encountered in the process of PBL height detection. In particular, the results will contribute to improve synergic methodologies combining different instruments.

    Como referenciar este item
    Icon

  • IPEN-DOC 23286

    SANTOS, RENATA; CAMILO, DANIEL; ARAUJO, MARCOS P.; GUEDES, ANDERSON; HOELZEMANN, JUDITH; HENRIQUE, JOSE; LOPES, FABIO ; LANDULFO, EDUARDO ; MONTILLA-ROSERO, ELENA . First Urban Boundary layer determination from Lidar measurements at Natal (Brazil). In: WORKSHOP ON LIDAR MEASUREMENTS IN LATIN AMERICA, 9th, July 17-22, 2016, Santos, SP. Abstract... 2016.

    Abstract: The planetary boundary layer (PBL) height is a crucial parameter for air quality monitoring or forecasting and is essential for the interpretation of atmospheric constituents. A first determination of PBL height has been done through the identification of the minimum in the vertical gradients of Lidar profiles measured with a multiwavelength polarized Lidar system (named DUSTER) developed by the Laser Environmental Application Laboratory (LEAL) at the Nuclear and Energy Research Institute (IPEN, São Paulo, Brazil) and installed in February, 2016 at the Department of Atmospheric and Climate Sciences of the Federal University of Rio Grande do Norte (UFRN) in the city of Natal, Rio Grande do Norte, in the Brazilian Northeast (5°50’29 S, 35°11’57 W, sea level). In this work, the first information about daily evolution of urban PBL height in Natal is presented.

    Como referenciar este item
    Icon

  • IPEN-DOC 23285

    SALANI, MARIA H.G. de A. ; LANDULFO, EDUARDO . Monitoring of pollutants and environmental impact dispersion in santos estuary by the technique LIDAR. In: WORKSHOP ON LIDAR MEASUREMENTS IN LATIN AMERICA, 9th, July 17-22, 2016, Santos, SP. Abstract... 2016.

    Abstract: The atmosphere is a medium that deforms easily through its movements carrying the gaseous compounds and particles away from places where they were generated. In big cities, due to its complex structure, it is very difficult to identify and quantify their polluting sources, which impacts directly on questions regarding the reduction of pollutants’ emission, that are aimed to improve the health of the population. Estuaries may suffer indirect contamination through atmospheric deposition, which can be one of the main forms of contamination of the aquatic environment. This study seeks to identify and to quantify the presence of suspended particulate material in the port of Santos area, which receives pollution of emission of vehicles, ships, industrial operations. The chosen area for monitoring, in order to quantify and to measure this particulate material, was the estuary of the Port of Santos, located in the state of São Paulo, in the city of Santos, Lat. 23º59’24’’S e Long. 46º20’12’’W. The methodology used is the remote sensing technique known as laser lidar to monitor, in near real time, atmospheric emissions of particulate matter and trace gases, from the estuary of the Port of Santos-SP. The lidar operates a commercial pulsed-laser transmission system, and its configuration offers complete overlap between the system's field of vision and the laser beam at an altitude of approximately 180m. It is intended to find a methodology capable of monitoring the emissions of particulate material in the air, based on the processing of data from the measurement performed by the Lidar’s system. It allows the identification of the sources and characteristics (size and type) of the particulate material; as well as the pattern of its dispersion can be identified and studied.

    Como referenciar este item
    Icon

  • IPEN-DOC 23284

    GUERRERO-RASCADO, J.L.; LANDULFO, E. ; LOPES, F.J.S. ; BARBOSA, H.M.J.; GOUVEIA, D.A.; FORNO, R.N.; SANCHEZ, M.F.; BASTIDAS, A.E.; NISPERUZA, D.; MONTILLA-ROSERO, E.; SILVA, A.; HOELZEMANN, J.J.; RISTORI, P.; QUEL, E.J.; BARJA, B.; ANTUNA, J.A.. Checking the instrumental performance of LALINET: quality assurance during the period 2014-2015. In: WORKSHOP ON LIDAR MEASUREMENTS IN LATIN AMERICA, 9th, July 17-22, 2016, Santos, SP. Abstract... 2016.

    Abstract: The recently published study of Guerrero-Rascado et al. (2016) reporting a diagnosis on the LALINET network instrumentation initiated the analysis of the instrumental status of LALINET. The current study presents the instrumental activities performed on LALINET with the aim of improving the monitoring capabilities of this network to characterize the aerosol particle field on continental scale. To guarantee the quality and standardization of products offered by the LALINET network, a robust quality assurance program based on regular instrumental tests (inherited from EARLINET, the European Aerosol Research Lidar Network, Pappalardo et al. [2014]) has been applied. In particular, the quality assurance tests performed were: (i) quadrants telecover and in-out telecover tests to analyze lidar signals in the near range, (ii) Rayleigh fit to analyze lidar signals in the far range, (iii) dark current measurement to evaluate electronic noise and (iv) zero-bin calibration / trigger delay to evaluate time delays. These tests, mandatory for all LALINET systems, were carried out annually. This paper reveals the evolution of the instrumental quality in the network, highlighting the improvements/degradations which have been taking place under the period of analysis 2014-2015.

    Como referenciar este item
    Icon

  • IPEN-DOC 23283

    GORDILLO, M.; MONICK, G.; ROMAN, R.; LYAMANI, H.; TITOS, G.; GUERRERO-RASCADO, J.L.; BASTIDAS, A.E.; HOELZEMANN, J.J.; LANDULFO, E. ; BARBOSA, H.M.J.; MONTILLA-ROSERO, E. ; NISPERUZA, D.. Absorbing aerosols monitoring over remote regions. In: WORKSHOP ON LIDAR MEASUREMENTS IN LATIN AMERICA, 9th, July 17-22, 2016, Santos, SP. Abstract... 2016.

    Abstract: Although the Earth’s atmosphere consists primarily of gases, aerosols and clouds play important roles in the Earth’s energy balance and climate. Aerosols alter the Earth’s energy budget directly by scattering and absorbing radiation and indirectly by modifying cloud microphysical and radiative properties. Evaluation of aerosol effects on climate must take into account high spatial and temporal variation of aerosol amounts and properties as well as the aerosol interactions with clouds and precipitation. Combustion of carbonaceous fuels for the production of energy inevitably results in the emission of gas and particulate air pollutants. A large fraction of the emitted particles are light absorbing carbonaceous aerosols that exhibit very large optical absorption across the spectrum. The most measured light absorbing carbonaceous aerosol is black carbon (BC), a unique primary tracer for combustion emissions as it is not emitted by any other sources. In the project “Absorbing aerosols monitoring over remote regions”, we have used a lightweight aircraft to obtain information on the BC and other light absorbing carbonaceous aerosols concentrations. Thus, we have determined the regional heterogeneity and vertical distribution in the atmosphere of carbonaceous aerosols with a minor payload and for a fraction of the costs associated with large airborne platforms. The aircraft has been equipped with an aethalometer to measure aerosol absorption at different wavelengths. The wavelength dependence of absorption will enable us to apportion BC concentrations to two major sources: biomass and fossil fuel combustion. Measurements have been performed throughout the flight including regions where no or very little measurements have been performed in the past, such as the Arctic, Africa, South America and over the Atlantic Ocean. Along the flight special spiral flights over lidar stations operated in the frame of the global network GALION were carried out and were analyzed in this work. Plumes of pollution and mineral dust were detected and by the use of back trajectories the possible source regions were identified.

    Como referenciar este item
    Icon

  • IPEN-DOC 23282

    NAKEMA, WALTER M. ; HAO, ZUOQIANG; LOPES, FABIO J.S. ; LANDULFO, EDUARDO . Estimation in situ of extinction coefficient of particles using Cavity Ring-Down Spectrometer. In: WORKSHOP ON LIDAR MEASUREMENTS IN LATIN AMERICA, 9th, July 17-22, 2016, Santos, SP. Abstract... 2016.

    Abstract: Lidar measurements present limitation regarding to the determination of extinction coefficient on the surface (where most aerosol particles are concentrated) due to geometrical issues and overlap functions. An attempt to overcome these feature, it is purposed an approach using a Cavity Ring-Down Spectrometer (CRDS) for monitoring in situ the optical properties of aerosols in a continuous visible-range between 630 and 650 nm. The CRDS is a very sensitive and calibration-free direct absorption spectroscopic technique that provides absolute values of optical extinction by samples that scatter and absorb light. Simultaneous measurements of scattering and extinction coefficients were performed by an elastic lidar in order to compare the respective magnitude of values.

    Como referenciar este item
    Icon

  • IPEN-DOC 23281

    COSTA, RENATA F. da ; LANDULFO, EDUARDO ; GUARDANI, ROBERTO; WRIEDT, THOMAS; VESELOVSKII, IGOR; KORENSKIY, MIKHAIL. Particle size distribution retrieval from measurements of industrial flare using an elastic lidar. In: WORKSHOP ON LIDAR MEASUREMENTS IN LATIN AMERICA, 9th, July 17-22, 2016, Santos, SP. Abstract... 2016.

    Abstract: The emission of pollutants in megacities and industrial areas can have strong impacts on climate and health. In recent years, there has been a growing concern about air emissions containing nanometric particles whose presence, together with volatile organic compounds, nitrogen oxides, and others, can result in the formation of a series of gaseous pollutants and aerosol. More accurate measurements of the concentration and size distribution of soot are important not only from an environmental point of view, but also to human health. The objective of this study was to determine the particle size distribution in the chimney of a refinery in Cubatao. For this, it used an approach based on inversion methods traditionally used to calculate parameters of atmospheric aerosols, the context of aerosols of industrial flares. The results were consistent with the scientific literature, it is possible to determine some parameters of size distribution of particles from an industrial torch flame using a system handling three wavelengths with an acceptable level of mismatch. A study by the Angstrom exponent was carried out in order to validate the inversion algorithm developed in this work. The results of this study showed that corroborate experimental data with the theoretical curves and thus the algorithm can be used as a tool for measuring atmospheric emissions from industrial torches. The development of this project will be an important step, not only from a technological point of view, but also rather as a resource to address emission problems that may arise in the future, among the measures aimed at controlling climate change.

    Como referenciar este item
    Icon

  • IPEN-DOC 23280

    LOPES, FABIO J.S. ; GUERRERO-RASCADO, JUAN L.; LANDULFO, EDUARDO ; KROTKOV, NICKOLAY; HUGHES, ERIC; SILVA, ARLINDO da. Aerosol layer observation of 2015 Calbuco volcanic eruption over the LALINET São Paulo station. In: WORKSHOP ON LIDAR MEASUREMENTS IN LATIN AMERICA, 9th, July 17-22, 2016, Santos, SP. Abstract... 2016.

    Abstract: On the 22nd of April 2015, the Calbuco volcano sited at the South region of Chile had its first eruption since 1972, injecting a huge plume of volcanic aerosol particles and gases up to 21 km into the atmosphere. As part of the Latin America Lidar Network’s (LALINET) aim to monitor any atmospheric event the LALINET São Paulo station (SPU) started continuous observation in order to monitor the dispersion of volcanic aerosol layer and their altitude and optical properties. After 5 days, on 27 April 2015, some volcanic plumes arrived over the Metropolitan area of São Paulo (MASP) and were detected by the SPU system within the altitude range of 18-19 km. The timing and altitude of SPU observations coincide with transport and dispersion simulations of the volcanic cloud’s arrival at São Paulo, from the Goddard Earth Observing System Model, version 5 (GEOS-5) and Goddard Chemistry Aerosol Radiation and Transport (GOCART) model from NASA Goddard Space Flight Center. The models simulate the volcanic eruption’s injection of SO2, SO4, and ash into the atmosphere and the advection of the volcanic plume away from the volcano. The purpose of this study is to determine the optical properties of the volcanic plume such as AOD and Lidar ratio. Applying the transmittance method used previously for cirrus clouds it was possible to retrieve the AOD value of 0.16 ± 0.21 and a lidar ratio of 64 ± 4 sr.

    Como referenciar este item
    Icon

  • IPEN-DOC 23279

    GOUVEIA, DIEGO A.; BARJA, BORIS; BARBOSA, HENRIQUE de M.J.; LANDULFO, EDUARDO ; ALMEIDA, PAULO ; ROSAS, JORGE. Study cases of cirrus cloud radiative effect in manaus region during august – october 2014. In: WORKSHOP ON LIDAR MEASUREMENTS IN LATIN AMERICA, 9th, July 17-22, 2016, Santos, SP. Abstract... 2016.

    Abstract: Cirrus clouds radiative effect on shortwave radiation (CRE) has been studied combining lidar measurements with a state of the art radiative transfer code and solar radiation measurements at ground during September – October 2014. For this purpose, two days with persistent cirrus clouds over two Lidar sites, near Manaus - Brazil, were selected during this time (September 3 – 5, 2014). The UV Raman Lidar operates at 355 nm with 10 Hz and 95 mJ per pulse and the detection efficiency is high enough to give good signal to noise ratio at the cirrus altitudes even during daytime. The VIS Raman lidar operates at 532 nm with 20 Hz and 200 mJ per pulse. The UV Raman Lidar (UVRL) is located at T0e (2.89 ºS 59.97 ºW) and the VISRaman lidar in T2 (3.21 ºS 60.60 ºW). The radiative transfer code was adapted to the local conditions at the sites, using water vapor and temperature profiles from the operational radiosondes (~30 km) as well as locally measured surface albedo. Runs of the atmospheric radiative transfer code were conducted both under the presence of cirrus clouds and in clear sky conditions. The diurnal behavior of the CRE profile is analyzed and the presence of cirrus clouds is proved with instruments onboard Calipso and MODIS measurements. The calculated shortwave broadband cloud radiative effect values have negative sign, the mean daily cloud radiative effect ranging from −0.5 W/m2 to −52 W/m2, at the top of atmosphere and lower effect at the surface. A close correlation between the negative cirrus radiative effect and optical depth (anticorrelation) was found at the top of the atmosphere and at the surface when broadband solar irradiances calculations are analyzed. Also some calculations with different ice crystal sizes were conducted in order to evaluate the change in the CRE. Using these two lidar systems around the city of Manaus, the behavior of the cirrus clouds in the region was shown, during the second GoAmazon 2014, Intensive Operating Period (IOP2), from August 15 to October 15.

    Como referenciar este item
    Icon

  • IPEN-DOC 23278

    MONTILLA-ROSERO, ELENA ; LOPES, FABIO ; GUEDES, ANDERSON; HOELZEMANN, JUDITH; HENRIQUE, JOSE; GERRERO-RASCADO, JUAN L.; ALADOS, LUCAS; LANDULFO, EDUARDO . Tropospheric vertical profiles of aerosol optical parameter at Brazilian Northeastern: preliminary results. In: WORKSHOP ON LIDAR MEASUREMENTS IN LATIN AMERICA, 9th, July 17-22, 2016, Santos, SP. Abstract... 2016.

    Abstract: For understanding the dust transport processes and retrieving essential data for continuing validation and improvement of satellite products as for evaluating and improving aerosol and dust simulations with global and regional models as well, a multi-wavelength elastic depolarizing LIDAR system, developed by the Center of lasers and applications at IPEN, has been collocated with a sunphotometer CIMEL at Natal, northeastern city of Brazil. Through vertical profiling of dust optical and microphysical properties i.e, backscatter and extinction coefficients and particle depolarization ratio at 532 nm, the LIDAR system is planned to be a crucial point for progress on the assessment of aerosol radiative impact and aerosol-cloud interaction research. In this work, the first measurements carried out with the depolarization channels during February, March and April 2016, and the retrieved vertical profiles of aerosol backscatter coefficient are presented. Three-dimensional air mass back trajectory analysis was also conducted to determine the source regions of aerosols observed during this study.

    Como referenciar este item
    Icon

  • IPEN-DOC 23277

    MERIZIO, L.G.; BONTURIM, E. ; SILVA, I.G.N.; RODRIGUES, L.C.V.; BRITO, H.F.. Sr2MgSi2O7:Eu2+, Dy3+ long persistent luminescence material synthesized by microwave-assisted solid-state method (MASS). In: INTERNATIONAL CONFERENCE ON LUMINESCENCE, 18th, August 27 - September 1, 2017, João Pessoa, PB. Abstract... 2017.

    Abstract: Persistent luminescence materials can emit light for several hours after ceasing an irradiation source. Studies involving these materials have increased in lasts years mainly due to their singular properties 1. Dissilicates (Sr2MgSi2O7) present promising results, however the ordinary processes require high annealing temperatures and time (~1200 °C, 5 h). A current challenge is find alternatives synthesis methods that can reduce these elevated time and temperatures required. Microwave-Assisted Solid-State synthesis (MASS) is an excellent alternative that can achieve high temperatures in only a few minutes allowing synthesis times around 25 minutes. In this work, Sr2MgSi2O7:Eu2+,Dy3+ was synthesized by MASS. The SrCO3, (MgCO3)4(Mg(OH)2), SiO2, and R2O3, (R3+: Eu, Dy) precursors were grinded and then annealed in a domestic microwave oven using carbon as susceptor at 1000 W for 10 minutes and 900 W for 15 minutes. The excitation spectrum (Fig.1 left red) shows a broad band from 250 to 450 nm assigned to the Eu2+ 4f65d1 ← 4f7 transitions. Several Eu3+ 4f – 4f absorption peaks are observed at e.g. 396, 420 and 450 nm. The emission spectra (Fig. 1, left blue) shows a broad band centered at 470 nm arising from Eu2+ parity allowed 4f65d1 → 4f7 transition with no Eu3+ emission, which indicates energy transfer from Eu3+ to Eu2+. The CIE chromaticity diagram (Fig. 1 right) shows a blue color (x: 0.105; y: 0.236). An important characteristic of this material is the possibility to excite efficiently in the visible range (blue region), allowing applications in the storage of sun light energy.

    Como referenciar este item
    Icon

  • IPEN-DOC 23276

    FELINTO, M.C.F.C. ; GAIOLLO, E. ; MOREIRA, R.P. ; BONTURIM, E. ; BARBOSA, H.P.; SILVA, I.G.N.; PEDROSO, C.C.S.; BRITO, H.F.; TEOTONIO, E.E.S.; MALTA, O.M.L.. Submicron-crystals of BaWO4:Dy3+ and SrWO4:Dy3+ synthetized by green chemistry method. In: INTERNATIONAL CONFERENCE ON LUMINESCENCE, 18th, August 27 - September 1, 2017, João Pessoa, PB. Abstract... 2017.

    Abstract: Nowadays, the investigation of oxide based light emitting materials for white lightemitting diodes (w-LEDs) applications have generated interest due to the advantages such as long lifetime, low energy consumption, high luminescence efficiency and environmental friendliness [1]. These qualities make them a strong candidate for the solid state lighting, display devices, optoelectronic devices and light-emitting diodes (LEDs). In this work, we present results of Dy3+: BaWO4 and Dy3+: SrWO4 that present luminescence close to white color (Figure 1) left. They were synthetized using coprecipitation method. The emission spectra exhibit four emission transitions centered at around 486 nm, 576 nm, 665 nm and 760 nm corresponding to the transitions 4F9/26H15/2 (blue), 4F9/26H13/2 (yellow) 4F9/26H11/2 and 4F9/26H9/2 6F11/2 (red) respectively.Among these transitions 4F9/26H15/2 and 4F9/26H13/2 are observed to be strong whereas 4F9/26H11/2 transition is found to be relatively quite weak.The 4F9/26H13/2 transition is hypersensitive in nature and is strongly influenced by the environment around the Dy3+ ion site. It is observed in the luminescence spectra of these materials that the electric dipole transition is dominant compared to the magnetic dipole transition. The CIE diagram show emission close to white (Fig.1 right) for the five composition with little distortion of the color showing the influence of dopant concentration in the color of the emission.

    Como referenciar este item
    Icon

  • IPEN-DOC 23275

    FELINTO, M.C.F.C. ; MOREIRA, R.P. ; BONTURIM, E. ; BARBOSA, H.P.; BRITO, H.F.; TEOTONIO, E.E.S.; MALTA, O.M.L.. Submicro-crystals of BaWO4:Eu3+ and BaMoO4:Eu3+ synthetized by Pechini Method. In: INTERNATIONAL CONFERENCE ON LUMINESCENCE, 18th, August 27 - September 1, 2017, João Pessoa, PB. Abstract... 2017.

    Abstract: In the scheelite-related red phosphors, molybdate and tungstate are respectable high-quality host material. The central metal ions, Mo6+ and W6+, are coordinated to four oxygen atoms in tetrahedral symmetry (Td). Then, molybdate and tungstate demonstrate be chemically stable, red-emitting phosphors, very suitable for in lightening and bio-application.[1] Additionally, molybdate and tungstate phosphors have broad absorption bands owing to charge transfer (CT) from oxygen to metal in the near-UV region. Scheelite BaMoO4 and BaWO4 have almost ideal structure of the MO4 2− and display excellent thermal and hydrolytic stability [2-3]. Rare Earth Molybdates and Tungstate x%Eu:(BaMO4)3 submicron materials with smart photoluminescent properties were prepared using Pechini method. The powders were characterized by XRD, infrared absorption spectroscopy, thermal analyses, Scanning Electronic Microscopy and a criterions study of PL properties. These rare earth doped materials present highly intense red (Eu3+), luminescence under UV radiation. The structure change with the concentration of dopand, in this case concentration of Eu3+. The excitation spectra of these compounds presented broad bands arising from ligand–to–metal charge transfer (O→Mo6+, O→W6+ and O→Eu3+) and narrow bands related to 4f–4f intraconfigurational transitions. The emission spectra exhibited the 5D0→7FJ (J= 1–4) transitions, for the systems doped with Eu3+, while a broad band assigned to the LMCT (O→Mo;W) are observed when the excitation is monitored on the O→Mo;W LMCT state around 286 nm

    Como referenciar este item
    Icon

  • IPEN-DOC 23274

    FELINTO, MARIA C.F.C. ; SOUZA, LUANA A. ; BONTURIM, EVERTON ; NAKAMURA, LIANA K.O. ; CAMARGO, PEDRO; BRITO, HERMI F.; TEOTONIO, ERCULES E.S.; MALTA, OSCAR M.L.. Silver nanoparticle Plasmon Effect in the luminescence of X%Ag0@7.5%Eu(tta)3.TOPO-PVP system. In: INTERNATIONAL CONFERENCE ON LUMINESCENCE, 18th, August 27 - September 1, 2017, João Pessoa, PB. Abstract... 2017.

    Abstract: Surface Plasmon’s (SP) are known as collective oscillations of the conduction electrons induced by incident light at a metallic interface. They attract increasing interest for their applications to surface enhanced Raman spectroscopy (SERS), metal enhanced fluorescence (MEF), non-linear optics (NLO), etc. In the MEF fluorophores are not covalently coupled to the silver nanoparticles, which can facilitate the control of the fluorophores-to-metal separation, using a polymer thin film as the spacer, to study this phenomenon. Nowadays Plasmon coupled RE ion sistems are of great scientific significance [1-2]. In this work, the polyvinylpyrrolidone polymer, PVP, powder (0.3 g) was dissolved in ethanol or water (50 mL) followed by the addition of the required amount (from 7.5% in mass) of the Ln3+-complex in ethanol and added 0.1-10%(w/w) of Ag0 nanoparticles in relation of Eu3+ mass. The mixed solution was stirred (30 minutes), then cast onto a Petri dish. The polymer film was obtained after the total evaporation of the solvent. These films were characterized using IR spectroscopy, XPD, TGA, TEM, absorption and photoluminescence spectroscopy. The luminescence spectra of the films doped with Ag0 have the same profile of undoped films, exhibiting characteristic bands assigned to 5D07FJ (J= 1-4) at 581, 596, 615 and 702 nm. The intensity parameters of the film with and without Ag0 in various concentrations of metallic nanoparticle were determined. The only difference in these systems remaining in the intensity of the bands of Eu3+ ion that increase in a factor of ~1000X (Fig. 1).

    Como referenciar este item
    Icon

  • IPEN-DOC 23273

    BONTURIM, E. ; REIS, R. dos; MERIZIO, L.G.; RODRIGUES, L.C.V.; BRITO, H.F.; FELINTO, M.C.F.C. . Investigation of rare earth distribution in Sr2MgSi2O7:Eu2+,Dy3+ nanophosphors prepared by wet-chemical routes. In: INTERNATIONAL CONFERENCE ON LUMINESCENCE, 18th, August 27 - September 1, 2017, João Pessoa, PB. Abstract... 2017.

    Abstract: Luminescent materials have been developed through ne chemistry methods that help to achieve a better control of parameters such as morphology, particle size, atomic homogeneity and high purity single phase in low temperature synthesis.[1, 2] In this work, the material Sr1:98MgSi2O7 nanoparticles doped with 0.01 mol of Eu2+ and codoped with 0.01 mol of Dy3+ was prepared via Pechini and Condensation methods. Post-annealing by microwave assisted method using granular coal as the susceptor/reducing agent [3] was applied on both materials and their luminescent properties were compared. The structural position of Eu2+ used as the activator ions determines photoluminescence properties. The luminescence spectra of Sr2MgSi2O7:Rn+ nanomaterial (R: Eu2+, Dy3+) shows a high emission broad band assigned to the intercon gurational transition 4f65d1 ! 4f7 centered around 460 nm, which is overlapped with a low emission lines attributed to the 4F9=2 ! 6H13=2 transition of Dy3+ ion (Fig. 1b). Elemental mappings obtained by Energy Dispersive X-Ray (EDX) presents dopants more likely to be found at the edge, indicating a possible segregation of rare earths to the grain boundaries during the synthesis (Fig. 1c). The persistent luminescence phenomenon emitting in a blue region was observed for both nanomaterials.

    Como referenciar este item
    Icon

  • IPEN-DOC 23272

    PIRES, NATALIA S.M.; DANTAS, ANDREA T.; DUARTE, ANGELA L.B.P.; AMARAL, MARCELLO M. ; FERNANDES, LUANA O.; DIAS, TEREZA J.C.; MELO, LUCIANA S.A.; MOTA, CLAUDIA C.B.O.; SILVA, PATRICIA F.C.; GOMES, ANDERSON S.L.. Labial mucosa evaluation in systemic sclerosis using optical coherence tomography. In: CONFERENCE ON LASERS AND ELECTRO-OPTICS, May 14-19, 2017, San Jose, California, USA. Resumo expandido... Washington, DC, USA: OSA, 2017. p. JW2A.51.

    Abstract: A clinical study was developed to evaluate the labial mucosa using optical coherence tomography in 33 systemic sclerosis patients and 35 healthy control. The mucosa presented statistically significant characteristics between the groups.

    Como referenciar este item
    Icon

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

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

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

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

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

Exemplo:

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

Autor: Maprelian

Título: loss of coolant

Tipo de publicação: Texto completo de evento

Ano de publicação: 2015

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

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

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

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

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

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

ATENÇÃO!

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

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

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

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


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

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

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

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

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