Navegação IPEN por Autores IPEN "OTUBO, LARISSA"

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  • IPEN-DOC 26862

    GARCIA, PAULO R.A.F.; PRYMAK, OLEG; GRASMIK, VIKTORIA; PAPPERT, KEVIN; WLYSSES, WAGNER; OTUBO, LARISSA ; EPPLE, MATTHIAS; OLIVEIRA, CRISTIANO L.P.. An in situ SAXS investigation of the formation of silver nanoparticles and bimetallic silver–gold nanoparticles in controlled wet-chemical reduction synthesis. Nanoscale Advances, v. 2, n. 1, p. 225-238, 2020. DOI: 10.1039/c9na00569b

    Abstract: We present a study on the formation of silver (Ag) and bimetallic silver–gold (AgAu) nanoparticlesmonitored by in situ SAXS as well as by ex situ TEM, XRD and UV-vis analysis in a flow reactor at controlled reaction temperature. The formation mechanism of the nanoparticles is derived from the structural parameters obtained from the experimental data. The evolution of the average particle size of pure and alloyed nanoparticles shows that the particle growth occurs initially by a coalescence mechanism. The later growth of pure silver nanoparticles is well described by Ostwald ripening and for the alloyed nanoparticles by a process with a significantly slower growth rate. Additionally, the SAXS data of pure silver nanoparticles revealed two major populations of nanoparticles, the first one with a continuous crystal growth to a saturation plateau, and the second one probably with a continuous emergence of small new crystals. The particle sizes obtained by SAXS agree well with the results from transmission electron microscopy and X-ray diffraction. The present study demonstrates the capability of an in situ investigation of synthesis processes using a laboratory based SAXS instrument. Online monitoring of the synthesis permitted a detailed investigation of the structural evolution of the system.

    Palavras-Chave: nanoparticles; small angle scattering; x-ray diffraction; silver; bimetals; gold; monte carlo method; nanostructures; alloys

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  • IPEN-DOC 28751

    RODRIGUES, PRISCILA S. ; MATOS, IZABELA T. ; SALES, TATIANE S. ; BURIMOVA, ANASTASIA ; CABRERA-PASCA, GABRIEL; PEREIRA, LUCIANO F. ; SAXENA, RAJENDRA N. ; OTUBO, LARISSA ; CARBONARI, ARTUR W. . Annealing effect on the structural and local magnetic properties of nickel ferrite nanoparticles studied by hyperfine interaction measurements. In: ANNUAL CONFERENCE ON MAGNETISM AND MAGNETIC MATERIALS, 65th, November 2-6, 2020, Online. Abstract... 2020.

    Abstract: Nickel ferrite in the form of nanoparticles is a technologically important material that can be applied for the production of biosensors, catalysts, drug delivery, and magnetic resonance contrast agents. In this work NiFe O samples comprising spherical nanoparticles of ~6 nm in diameter have been synthesized via a thermal decomposition route. The quality control of the samples was carried out with conventional techniques including X-ray diffraction and transmission electron microscopy. Post-synthesis XRD pattern revealed textured spinel NiFe O . Local magnetic properties were examined with Time Differential Perturbed Angular Correlation (TDPAC) spectroscopy within the 12 - 773K temperature range with In( Cd) probe introduced into the samples at synthesis. Quasi-static magnetic properties were observed (including above room temperature), as expected due to the small time window of TDPAC. The TDPAC results shown in Fig. 1 were analyzed using a model with combined electric quadrupole and magnetic dipole interactions. An expressive dynamic interaction was observed upon heating after synthesis. A theoretical model based on the Brillouin function for different ionic moments was applied to study the evolution of the hyperfine magnetic field with temperature (see Fig. 1-2) and allowed to attribute the magnetic interaction to the probe location at Fe3+ site. Site occupancy and the interplay between magnetic and structural properties are discussed with respect to application perspectives.

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  • IPEN-DOC 28095

    VIEIRA, ANA C.D.; KODAMA, YASKO ; OTUBO, LARISSA ; SANTOS, PAULO S. ; VASQUEZ, PABLO A.S. ; GARCIA, RAFAEL H.L. . Application of gamma irradiation to conservation: effects of ionizing radiation on the color of featherwork. In: ICOM-CC TRIENNIAL CONFERENCE, 19th, May 17-21, 2021, Beijing, China. Abstract... Paris, France: International Council of Museums, 2021.

    Abstract: Featherwork is one of the most remarkable categories of material culture produced by Brazilian indigenous peoples due to its technical qualities and aesthetic beauty. Weapons, baskets, and musical instruments are frequently decorated with feathers, which are also used in body adornments that, in addition to their aesthetic purpose, are intended to convey information about the wearer, their position within a group, and the cultural values that they wish to transmit. The preservation of this type of artifacts is demanding given the biological cycle of the organic materials that compose them, which are inevitably subject to various stages of deterioration. In addition to the damage resulting from their use and perishable materials, these ethnographic objects are exposed to a new environment when they are incorporated into museum collections, where their existence must be prolonged. Since Brazil’s tropical climate often leads to pest proliferation, their degradation can be exacerbated by the action of insects such as moths and microorganisms such as fungi with irreversible consequences, making their conservation a daily challenge. Although the art of featherwork is still practiced by indigenous communities, the scarce supply of raw materials and contact with the tribes involved has reduced the scale of production. The preservation of this material heritage is thus very important, particularly in ethnographic museums. The use of gamma radiation for the disinfestation of cultural heritage artifacts and archived materials has been shown to be a safe process and an excellent alternative to traditional methods, which usually involve toxic chemical pesticides. Ionizing radiation has been used for more than 40 years and, since 2004, the Multipurpose Irradiator at the Institute of Energy and Nuclear Research (IPEN), a pioneering technology developed in Brazil, has made its application to cultural heritage a reality. With more than 20,000 cultural artifacts irradiated, IPEN is currently the national and international reference center for the use of radiation technology applied to the preservation of cultural heritage collections. Several studies have been conducted to determine the optimal dose required to eliminate contamination by biological agents in organic materials such as wood, leather, and feathers.A maximum dose of 10 kGy is recommended for featherwork in order to avoid affecting the physical and chemical properties of this type of material. This poster reports on the results of the effects of ionizing radiation on the color and morphological properties of a featherwork from the Museum of Archaeology and Ethnology at the University of São Paulo (MAE/USP). Samples of feathers were selected and irradiated with gamma rays at the Multipurpose Gamma Irradiation Facility, applying absorbed doses of between 0.5 and 200 kGy. The samples were chosen according to the color of the feathers and then photographed and analyzed using colorimetry based on the CIELAB 1976 color space scale before and 48 hours after irradiation and scanning electron microscopy. There were no significant changes in morphological and color properties within the disinfestation range applied.

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  • IPEN-DOC 25853

    PINHEIRO, ANDRE L.G.; CARMO, JOSE V.C. do; CARVALHO, DAVI C.; OLIVEIRA, ALCINEIA C.; RODRIGUEZ-CASTELLON, ENRIQUE; TEHUACANERO-CUAPA, SAMUEL; OTUBO, LARISSA ; LANG, ROSSANO. Bio-additive fuels from glycerol acetalization over metals-containing vanadium oxide nanotubes (MeVOx-NT in which, Me=Ni, Co, or Pt). Fuel Processing Technology, v. 184, p. 45-56, 2019. DOI: 10.1016/j.fuproc.2018.11.008

    Abstract: The biodiesel production has led to a drastic surplus of glycerol and catalytic conversion of glycerol into valueadded products is of great industrial importance. Thus, the acetalization of glycerol with ketone or aldehydes allows the glycerol transformation into bio–additive fuels. In this work, metals-containing vanadium oxides nanotubes (MeVOx NT in which, Me=Co, Pt or Ni) have been synthesized with additional internal porosity and tested in the acetalization of glycerol with acetone (AG) for valuable biofuels production. The catalysts showed remarkable performances in the AG reaction. Furthermore, by variation of the composition, catalyst loading and temperature and using distinct substrates (butyraldehyde, furfuraldehyde and benzaldehyde), NiVOxNT is active, being very selective to solketal and reciclable for 4 times in the AG reaction. On the contrary, pure VOx NT easily deactivated due to the structure agent removal during the reaction, which promote the collapse of the tubular structure. The CoVOxNT and PtVOxNT catalysts did not exhibit such a stable structure and easily deactivated in the reaction due to leaching of the metals oxides during the AG.

    Palavras-Chave: biodiesel fuels; glycerol; nanotubes; vanadium oxides; biofuels; acetates; catalysts; acetone

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  • IPEN-DOC 26543

    SANTOS, EMANUELLA C. dos; BATISTA, BEATRIZ da S.; LIMA, RUANA C.; ALENCAR, LUCIANA M.R.; SANTOS, ADENILSON O. dos; PEDROCHI, FRANCIANA; OTUBO, LARISSA ; LANG, ROSSANO; SILVA, LUZELI M. da. Bioactivity study of Co-Cr alloys doped with tantalum for biomedical applications. In: BRAZIL MRS MEETING, 18th, September 22-26, 2019, Balneário Camburiú, SC. Abstract... São Carlos, SP: Aptor Software, 2019. p. 1017-1018.

    Abstract: Co-Cr alloys are well known because of its high wear resistance, mechanical strength and corrosion resistance due to the chromium oxide passive layer formation that protects the material surface [1].The addition of alloying elements, particularly Mo and W, improve the properties of Co-Cr bioalloys, although these materials can still be improved to meet the requirements for a biomaterial.Thus, considering that tantalum is a bioactive metal, it can be an interesting option to improve the biocompatibility properties of these alloys[2].The present study aims the synthesis and in vitro evaluation bioactivity of Co-Cr alloy doped with tantalum.The synthetized alloys were submitted to a surface treatment and subsequentlyimmersed in Simulated Body Fluid (SBF) for 28 days. The samples bioactivity was evaluated by using X- ray Diffraction (DRX), Scanning Electron Microscopy (SEM), Dispersive Energy Spectroscopy (EDS) and Atomic Force Microscopy (AFM) techniques. X- ray diffraction analysisin the SBF immersed samples shown a small intensity peak characteristicof hydroxyapatite while MEV and EDS results revealeda surface structure with the presence of P, Mg, Ca and Oelements. The grain growth dynamics on the samples surfaces was observed by using AFM measurements.

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  • IPEN-DOC 21155

    RIBEIRO, AMON S.L. ; GARCIA, RAFAEL H.L. ; OTUBO, LARISSA ; PAULA, CAROLINA M. de ; DURAZZO, MICHELANGELO . Caracterização e quantificação de fases de alumina por difratometria de raios X para utilização como material adsorvedor em geradores de tecnécio - 99m. In: INTERNATIONAL NUCLEAR ATLANTIC CONFERENCE; MEETING ON NUCLEAR APPLICATIONS, 12th; MEETING ON REACTOR PHYSICS AND THERMAL HYDRAULICS, 19th; MEETING ON NUCLEAR INDUSTRY, 4th, October 4-9, 2015, São Paulo, SP. Proceedings... 2015.

    Palavras-Chave: aluminium oxides; x-ray diffraction; adsorbents; technetium 99

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  • IPEN-DOC 21137

    ROCHA, MARCELO S. ; CABRAL, EDUARDO L.L. ; SABUNDJIAN, GAIANE ; YORIYAZ, HELIO ; LIMA, ANA C.S.; BELCHIOR JUNIOR, ANTONIO ; PRADO, ADELK C. ; MADI FILHO, TUFIC ; ANDRADE, DELVONEI A. ; SHORTO, JULIAN M.B. ; MESQUITA, ROBERTO N. ; OTUBO, LARISSA ; BAPTISTA FILHO, BENEDITO D. ; PINHO, PRISCILA G.M.; RIBATSKY, GHERHARDT; MORAES, ANDERSON A.U. de. Characterization of physical properties of Alsub(2)Osub(3) and ZrOsub(2) nanofluids for heat transfer applications. In: INTERNATIONAL NUCLEAR ATLANTIC CONFERENCE; MEETING ON NUCLEAR APPLICATIONS, 12th; MEETING ON REACTOR PHYSICS AND THERMAL HYDRAULICS, 19th; MEETING ON NUCLEAR INDUSTRY, 4th, October 4-9, 2015, São Paulo, SP. Proceedings... 2015.

    Palavras-Chave: aluminium oxides; zirconium oxides; physical properties; nanofluids; viscosity; cooling; heat transfer; scanning electron microscopy

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  • IPEN-DOC 28995

    GARCIA, LUIS M.S. ; ZAMBIAZI, PRISCILLA J. ; CHAIR, KHAOULA; DOAN, TUAN D.; RAMOS, ANDREZZA S. ; NANDENHA, JULIO ; SOUZA, RODRIGO F.B. de ; OTUBO, LARISSA ; DUONG, ADAM; NETO, ALMIR O. . cis-[6-(pyridin-2-yl)-1,3,5-triazine-2,4-diamine](dichloride) palladium(II)-based electrolyte membrane reactors for partial oxidation methane to methanol. ACS Omega, v. 7, n. 28, p. 24249-24255, 2022. DOI: 10.1021/acsomega.2c01463

    Abstract: Methane is an abundant resource and the main constituent of natural gas. It can be converted into higher value-added products and as a subproduct of electricity co-generation. The application of polymer electrolyte reactors for the partial oxidation of methane to methanol to co-generate power and chemical products is a topic of great interest for gas and petroleum industries, especially with the use of materials with a lower amount of metals, such as palladium complex. In this study, we investigate the ideal relationship between cis-[6-(pyridin-2-yl)-1,3,5-triazine-2,4-diamine(dichloride)palladium(II)] (Pd-complex) nanostructure and carbon to obtain a stable, conductive, and functional reagent diffusion electrode. The physical and structural properties of the material were analyzed by Fourier transform infrared (FT-IR) and Raman spectroscopies, transmission electron microscopy (TEM), and X-ray powder diffraction (XRD) techniques. The electrocatalytic activity studies revealed that the most active proportion was 20% of Pd-complex supported on carbon (m/m), which was measured with lower values of open-circuit and power density but with higher efficiency in methanol production with reaction rates of r = 4.2 mol L–1·h–1 at 0.05 V.

    Palavras-Chave: electrolytes; fuel cells; membranes; methane; oxidation; electrocatalysts

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  • IPEN-DOC 30169

    SILVA, CRYSTIAN W.C. da ; OTUBO, LARISSA ; SOUZA, KATIUSSE S. de ; CARBONARI, ARTUR W. ; CORREA, BRUNO S. ; FREITAS, RAFAEL S. de; PASCA, GABRIEL A.; COSTA, CLEIDILANE S.. Comparative local analysis of Ni/Ni3C nanoparticles synthed with oleylamine/oleic acid and oleylamine/palm kernel oil ligand pairs: structural and magnetic properties. In: BRAZIL MRS MEETING, 21st, October 1-5, 2023, Maceió, AL. Abstract... São Carlos, SP: Aptor Software, 2023. p. 1805-1805.

    Abstract: In recent decades, Ni/Ni3C nanoparticles have been a topic of interest, especially for their catalytic and magnetic properties, promising as electrocatalysis, for example [1]. These systems are usually obtained by chemical methods, in the presence of ligands responsible for controlling their structure and morphology [2]. In this work, we carried out a comparative study of the hyperfine interactions occurring in Ni/Ni3C nanoparticles, synthed by thermal decomposition in the presence of oleylamine/oleic acid and oleylamine/palm kernel oil ligand pairs, at 513 K, for 3 hours. The local analysis was performed using perturbed correlation spectroscopy (PAC) in the temperature range from 30K to 300K, using the 111Cd probe, implanted in the samples by diffusion, during the synthesis. The parameters of the hyperfine interactions were compared to the results obtained by XRD, TEM and magnetization, indicating the obtainment of Ni/Ni3c nanoparticles of the core-shell type, showing a higher Ni3C content, greater distribution and lower saturation magnetization for nanoparticles synthed with palm kernel oil compared to those obtained with oleic acid. In addition, the hyperfine parameters showed the existence of regions with a quadrupole frequency of 24 MHz and a magnetic hyperfine field of 1T in both samples, which may be indicative of carbon-deficient Ni3C regions, predicted in the literature [3].

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  • 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.

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  • IPEN-DOC 26121

    VALLI, RICARDO; OLIVEIRA, FELIPE S.; OTUBO, LARISSA ; LANG, ROSSANO. CrSi2 layer synthesized by high current Cr ion implantation for Schottky diode applications. In: BRAZILIAN MRS MEETING, 17th, September 16-20, 2018, Natal, RN. Abstract... São Carlos: Aptor Software, 2018. p. 1135-1136.

    Abstract: Among the transition-metal silicides, CrSi2 has received considerable attention as a material for silicon-based technologies because of its high-temperature stability, oxide-forming ability and semiconducting properties [1]. Its use in infrared photodetectors and Schottky barrier contacts has been of interest. Previous studies indicate that bulk CrSi2 has a hexagonal structure and p-type semiconductor character with a band gap of ≈ 0.35 eV [2]. In this work, we have synthesized and investigated the electrical-structural correlation of CrSi2 buried layer produced by high current Cr ion implantation. For this, Cr+ ions at an energy of 180 keV were implanted at high temperature (550 °C) at a fluence of 4x1017 ion/cm2. An n-type (001) surface-oriented Czochralski Si wafer (thickness 500 mm, resistivity 10-20 Ωcm) was used as host matrix. The chromium beam current density during implantation was about 6 μA/cm2. The Schottky diode formation consisted of the junction of metal and semiconductor, in this case, Au contact, and the CrSi2/Si, respectively. The formation of the crystallographic phase was identified by grazing incidence Xray diffraction. The buried layer morphology of silicide into substrate subsurface was revealed through scanning electron microscopy. Electrical conduction was characterized by resistivity measurements as a function of temperature (50 - 300 K), where two types of regimes are observed, i.e., two gaps: one of low temperature and one of high temperature (270 K). The electronic mobility was also obtained as a function of temperature by means Hall effect measurements. The transport of electrons above the potential barrier to the metal (Schottky barrier height), was determined by current-voltage curves (IxV) at room temperature.

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  • IPEN-DOC 28161

    SANTOS, RENATA V.; CABRERA-PASCA, GABRIEL A.; COSTA, CLEIDILANE S.; BOSCH-SANTOS, BRIANNA ; OTUBO, LARISSA ; PEREIRA, LUCIANO F.D. ; CORREA, BRUNO S. ; EFFENBERGER, FERNANDO B. ; BURIMOVA, ANASTASIA ; FREITAS, RAFAEL S.; CARBONARI, ARTUR W. . Crystalline and magnetic properties of CoO nanoparticles locally investigated by using radioactive indium tracer. Scientific Reports, v. 11, n. 1, p. 1-13, 2021. DOI: 10.1038/s41598-021-99810-y

    Abstract: We herein report a comprehensive investigation on the magnetic, structural, and electric properties of CoO nanoparticles with different sizes by local inspection through hyperfine interactions measured in a wide range of temperatures (10–670 K) by using radioactive 111In(111Cd) tracers with the perturbed angular correlations technique. Small cobalt oxide nanoparticles with the characteristic size of 6.5 nm have been prepared by the wet chemical route that turned out to be essential to incorporate radioactivity tracers during nucleation and growth of the particles. Nanocrystalline samples with 22.1 nm size were obtained by thermal treatments under low pressure of helium at 670 K. The hyperfine data were correlated with X-ray diffraction, ZFC–FC magnetic measurements, and transmission electron microscopy to describe the structure, magnetic properties, size, and shape of samples. An analysis of the temperature evolution of hyperfine parameters revealed that the structural distortion and the magnetic disorder in the core and on the surface layer play an important role in the magnetic behavior of CoO nanoparticles.

    Palavras-Chave: cobalt oxides; nanoparticles; tracer techniques; indium

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  • IPEN-DOC 29212

    NASCIMENTO, JOAO P.S.; MARTINS, ANTONIO J.; BEZERRA, RITA de C.F.; BERTOLDO, GABRIELA M.; OLIVEIRA, ALCINEIA C.; BEZERRA, JOAO R.; ARAUJO, RINALDO S.; LANG, ROSSANO; OTUBO, LARISSA ; RODRIGUEZ-AGUADO, E.; RODRIGUEZ-CASTELLON, E.. Designed synthesis of nanostructured ZrO2 as active support for glycerol valorization reaction. Ceramics International, v. 49, n. 2, p. 1764-1778, 2023. DOI: 10.1016/j.ceramint.2022.09.140

    Abstract: Designed synthesis of nanostructured ZrO2 as support for glycerol valorization reaction was investigated. The nanocasting route was used to obtain the ZrO2 support possessing well-dispersed Cu and Zn nanoparticles. The solids were fully characterized by High-resolution transmission electron microscopy (HRTEM), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), Electron paramagnetic resonance (EPR), N2-physisorption isotherms, Temperature-programmed desorption of ammonia (NH3-TPD), Scanning electron microscopy coupled to energy dispersive spectroscopy (SEM-EDS) and Fourier transform infrared (FTIR) spectroscopy measurements. The resultant CuZn/ZrO2 catalyst presented here was distinguished by its unique mesostructured features and defective sites formation. The promotional effect of Cu nanoparticles on the activity illustrated that the formation of active acid sites of medium to strong strength can be modulated by adding a second metal to the catalyst. All these properties provided active solids for acetalization of glycerol with aldehydes and ketones due to the interaction between the active centers and the nanostructured support. Density functional theory (DFT) calculation showed the most favorable mechanistic route of low energy for biofuel additives production.

    Palavras-Chave: zirconium oxides; nanostructures; copper oxides; glycerol

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  • IPEN-DOC 29498

    BEZERRA, RITA de C.F.; MOTA, GABRIELA; VIDAL, RUTH M.B.; CARMO, JOSE V. do; SARAIVA, GILBERTO D.; CAMPOS, ADRIANA; OLIVEIRA, ALCINEIA C.; LANG, ROSSANO; OTUBO, LARISSA ; JIMENEZ, JOSE J.; RODRIGUEZ-CASTELLON, ENRIQUE. Effect of basic promoters on porous supported alumina catalysts for acetins production. Catalysts, v. 12, n. 12, p. 1-23, 2022. DOI: 10.3390/catal12121616

    Abstract: A facile strategy for the design of porous supports was obtained by modifying the sol-gel method followed by the wet impregnation technique. In this respect, herein, the acidity of the -Al2O3 phase was modulated by adding basic MgO, La2O3 or ZnO promoters to form binary supported catalysts. The Ni and Co dispersion on the supports associated with their tunable acidity and morphologies resulted in highly porous supported alumina-based catalysts. The physicochemical properties of the solids were comprehensively investigated by XRD, textural properties, Raman and FTIR spectroscopy, SEM-EDS, TEM, EPR and XPS analyses. The catalytic performances in the esterification of glycerol in the presence of acetic acid (EG) for the acetins production were evaluated. The highly dispersed NiO and Co3O4 active species on binary porous supports produced synergistic effects appearing to be the reason for the activity of the solids in the EG reaction. Under the optimized reaction conditions, NiCo/MgO-Al2O3 was found to be a robust solid with superior catalytic performance and improved stability in four reaction cycles with 65.0% of glycerol conversion with an exclusive selectivity of 53% for triacetin. The presence of Co2+/Co3+ and Ni2+ strongly interacting with the spinel -Al2O3 and MgAl2O4 phases, the latter having a large number of lattice oxygen species, was considered another active component besides those of Ni and Co in the esterification of glycerol.

    Palavras-Chave: porous materials; supports; catalysts; glycerol; esterification

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  • IPEN-DOC 28430

    PALHARIM, PRISCILA H.; FUSARI, BEATRIZ L.D. dos R.; RAMOS, BRUNO; OTUBO, LARISSA ; TEIXEIRA, ANTONIO C.S.C.. Effect of HCl and HNO3 on the synthesis of pure and silver-based WO3 for improved photocatalytic activity under sunlight. Journal of Photochemistry and Photobiology A: Chemistry, v. 422, p. 1-12, 2022. DOI: 10.1016/j.jphotochem.2021.113550

    Abstract: Heterogeneous photocatalysis have been considered an important and efficient alternative water and wastewater treatment process. In this area, different semiconductors, such as tungsten trioxide, have been investigated aiming to enhance photocatalytic performance. WO3 is known to be an efficient material with high stability in acidic conditions. In the present work, pure and Ag/AgCl-doped WO3 photocatalysts were synthesized by a simple hydrothermal method. A discussion of the effects of two pH-controlling agents, HCl and HNO3, in the final properties of the catalyst is reported for the first time. The materials were characterized by XRD, BET, SEM, EDS and UV–vis DRS. All catalysts showed similar or enhanced band gap values compared to a standard photocatalyst benchmark (TiO2 P25). The type of acid did not lead to significant differences in morphology or photocatalytic activity of undoped catalysts. In contrast, doped catalysts prepared using HCl resulted in particles of flower-like morphology, with higher uniformity and slightly narrower band gap values. Furthermore, the use of HCl in the synthesis of silver-doped WO3 resulted in catalysts containing AgCl, while Ag0 was the major dopant species when HNO3 was used. All materials exhibited good photocatalytic activity, with a maximum of 75.4% acetaminophen degradation under simulated sunlight achieved by the catalyst prepared with HCl and doped with 5% Ag-equivalent. For this catalyst, the degradation kinetics was found to be consistent with the Langmuir-Hinshelwood (L−H) model, and reusability tests showed no significant decrease in the degradation efficiency after four cycles. Finally, the effects of different scavengers suggest that O2•− species play a major role in acetaminophen degradation with the material containing WO3, Ag and AgCl.

    Palavras-Chave: photocatalysis; doped materials; hydrothermal synthesis; waste water; water treatment; heterogeneous catalysis

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  • IPEN-DOC 26550

    LIMA, LENI M.P.R. ; KODAMA, YASKO ; OTUBO, LARISSA ; SANTOS, PAULO S. ; VASQUEZ, PABLO A.S. . Effect of ionizing radiation on the color of botanical collections: exsiccata. In: VASQUEZ, PABLO A.S. (Ed.); NAGAI, MARIA L.E. (Coord.) INTERNATIONAL SYMPOSIUM ON GAMMA IONIZATION: TECHNOLOGY FOR PRESERVATION OF CULTURAL HERITAGE, 1st, October 25, 2019, São Paulo, SP. Abstract... São Paulo, 2019.

    Abstract: Conservation and preservation methods are essential to maintain the wholeness of botanical collections specially for dried herbarium specimens also known as exsiccates, usually referring to a set of identified specimens belonging to taxa and distributed among all herbaria around the world. These vegetal materials are subjected to fungal attack and insect pests threatening their entirety. In recent years, disinfection by ionizing radiation has become an effective strategy to preserve cultural heritage objects and archived materials with excellent results. In this work, the effects on color properties of exsiccates samples irradiated with gamma radiation from Co-60 with different absorbed doses were studied. The botanical pressed and dehydrated samples – exsiccates – were selected from the Dom Bento José Pickel Herbarium (SPSF), located at São Paulo (Brazil). Two exsiccate samples were selected: SPSF-4021 and SPSF-08821. These samples come from Asteraceae and Solanaceae family and were collected in 1946 and 1984, respectively. Families of selected botanical collections are very susceptible to biodegradation. The irradiation was performed at the Multipurpose Gamma Irradiation Facility at IPEN applying absorbed doses of 1 kGy, 6 kGy and 10 kGy. The selected ranged dose promotes insect disinfestation and fungal disinfection. Results were analyzed using colorimetry with CIELAB color space scale. Scanning electron microscopy were performed to analyze surface topography and elemental structure modifications by ionizing radiation and characterize the non-irradiated (0 kGy) and the effective disinfected (10 kGy) exsiccata samples. The results revealed no significant changes on colorimetric morphological properties of then irradiated samples. The color changes between the non-irradiated samples and the irradiated sample at the high absorbed dose are perceptible, but acceptable considering the adopted scale. The microscopy images of the non-irradiated and 10 kGy irradiated samples did not show significant differences in the topographic morphology of the exsiccata samples. The results obtained corroborate the studies of the application of gamma radiation to preserve materials of cellulosic origin. Subsequently and for continuity of this research, other samples will be analyzed.

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  • IPEN-DOC 26298

    LIMA, LENI M.P.R.; KODAMA, YASKO ; OTUBO, LARISSA ; SANTOS, PAULO de S. ; VASQUEZ, PABLO A. . Effect of ionizing radiation on the color of botanical collections: exsiccata. In: INTERNATIONAL NUCLEAR ATLANTIC CONFERENCE, October 21-25, 2019, Santos, SP. Proceedings... Rio de Janeiro: Associação Brasileira de Energia Nuclear, 2019. p. 2650-2661.

    Abstract: Conservation and preservation strategies are essential to manage botanical collections specially for dried herbarium specimens also known as exsiccates, usually referring to a set of identified specimens belonging to taxa and distributed among all herbaria around the world. Particularly, these collections are very sensitive to the attack of fungi and insects. In recent years, disinfection by ionizing radiation has become an effective strategy to preserve cultural heritage objects and archived materials with excellent results. In this work, the effects on color properties of gamma radiation on exsiccates samples were studied. Thus, six exsiccates, botanical pressed and dehydrated samples were selected from the Dom Bento José Pickel Herbarium (SPSF), situated at São Paulo (Brazil). Three of these samples comes from Asteraceae family and were collected in 1946, 1984 and 1986, while three other samples belong to Solanaceae family and were collected in 1953, 1984 and 2007. Families of selected botanical collections are very susceptible to biodegradation. The irradiation was performed at the Multipurpose Gamma Irradiation Facility at IPEN applying absorbed doses of 1 kGy, 6 kGy and 10 kGy, which are values of absorbed dose for disinfestation and disinfection. Results were analyzed using colorimetry with CIELAB color space scale and scanning electron microscopy. The results showed that there were no significant changes on colorimetric morphological properties of the samples.

    Palavras-Chave: absorbed radiation doses; botany; calorimetry; cobalt 60; disinfestation; fungi; gamma radiation; morphological changes; pest control; plants; radiation dose units; scanning electron microscopy

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  • IPEN-DOC 26542

    VIEIRA, ANA C.D.; KODAMA, YASKO ; OTUBO, LARISSA ; SANTOS, PAULO S. ; VASQUEZ, PABLO A.S. . Effect of ionizing radiation on the color of featherwork. In: VASQUEZ, PABLO A.S. (Ed.); NAGAI, MARIA L.E. (Coord.) INTERNATIONAL SYMPOSIUM ON GAMMA IONIZATION: TECHNOLOGY FOR PRESERVATION OF CULTURAL HERITAGE, 1st, October 25, 2019, São Paulo, SP. Abstract... São Paulo, 2019.

    Abstract: Featherwork collections are usually stored and managed by ethnographic museums. Even though the featherwork manufacturing is still practiced by the indigenous communities, the offer of raw material and the contact with the surrounding society ended up reducing the production scale of such objects. Consequently, the preservation of the culture heritage is very important, particularly in museums. Biodegradation can affect featherworks mainly by xylophagous insects and moths’ action. The tropical Brazilian weather contributes to the contamination and proliferation of insects and fungi making the preservation conditions difficult. The use of gamma radiation for the disinfection of cultural heritage objects and archived materials has shown to be a safe process and an excellent alternative to traditional methods usually involving high persistent and toxic chemical pesticides. In this work are presented the preliminary results of the ionizing radiation effects on the color and morphological properties of a featherwork from the Museum of Archeology and Ethnology of the University of São Paulo (MAE/USP). Samples of feathers were selected from the artifact and irradiated with gamma rays at the Multipurpose Gamma Irradiation Facility at IPEN, applying absorbed doses between 0.5 kGy to 200 kGy. Samples were firstly chosen according to feather colors, photographed and analyzed using colorimetry with CIELAB 1976 color space scale and scanning electron microscopy (SEM), just after and 48 hours after the irradiation process. The results shown had no significant changes on color and morphological properties within the disinfection absorbed dose range applied.

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  • IPEN-DOC 26299

    VIEIRA, ANA C.D.; KODAMA, YASKO ; OTUBO, LARISSA ; SANTOS, PAULO de S. ; VASQUEZ, PABLO A. . Effect of ionizing radiation on the color of featherwork. In: INTERNATIONAL NUCLEAR ATLANTIC CONFERENCE, October 21-25, 2019, Santos, SP. Proceedings... Rio de Janeiro: Associação Brasileira de Energia Nuclear, 2019. p. 2662-2676.

    Abstract: Featherwork collections are usually stored and managed by ethnographic museums. Even though the featherwork manufacturing is still practiced by the indigenous communities, the offer of raw material and the contact with the surrounding society ended up reducing the production scale of such objects. Consequently, the preservation of the culture heritage is very important, particularly in museums. Biodegradation can affect featherworks mainly by xylophagous insects and moths’ action. The tropical Brazilian weather contributes to the contamination and proliferation of insects and fungi making the preservation conditions difficult. The use of gamma radiation for the disinfection of cultural heritage objects and archived materials has shown to be a safe process and an excellent alternative to traditional methods usually involving high persistent and toxic chemical pesticides. In this work are presented the preliminary results of the ionizing radiation effects on the color and morphological properties of a featherwork from the Museum of Archeology and Ethnology of the University of São Paulo (MAE/USP). Samples of feathers were selected from the artifact and irradiated with gamma rays at the Multipurpose Gamma Irradiation Facility at IPEN, applying absorbed doses between 0.5 kGy to 200 kGy. Samples were firstly chosen according to feather colors, photographed and analyzed using colorimetry with CIELAB 1976 color space scale and scanning electron microscopy (SEM), just after and 48 hours after the irradiation process. The results shown had no significant changes on color and morphological properties within the disinfection absorbed dose range applied.

    Palavras-Chave: calorimetry; cobalt 60; color; disinfestation; feathers; fungi; insects; irradiation; morphological changes; preservation; radiation dose units; radiation doses; radiation effects; scanning electron microscopy

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  • IPEN-DOC 29099

    LIMA, LENI M.P.R. ; KODAMA, YASKO ; BAITELLO, JOAO B.; OTUBO, LARISSA ; SANTOS, PAULO de S. ; VASQUEZ, PABLO A.S. . Effects of ionizing radiation decontamination on botanical collections in herbaria. Radiation Physics and Chemistry, v. 202, p. 1-8, 2023. DOI: 10.1016/j.radphyschem.2022.110561

    Abstract: Herbaria collections are very sensitive to attacks from microorganisms and insects. Therefore, preservation strategies and appropriate treatments are essential to manage these artifacts. Decontamination by ionizing radiation has become an effective strategy to preserve cultural heritage objects and archived materials, achieving excellent results. Therefore, this work aimed to study the effects of Co-60 gamma radiation on botanical collections. To accomplish this, samples of exsiccates, including botanical pressed and dehydrated specimens from Asteraceae and Solanaceae families, collected on diferentes dates were selected from the Dom Bento José Pickel Herbarium (SPSF), located in São Paulo (Brazil). Irradiation was performed at the Multipurpose Gamma Irradiation Facility at IPEN, applying absorbed doses of 1 kGy, 6 kGy and 10 kGy. Gamma radiation effect was analyzed using colorimetry with CIELAB color space scale, scanning electron microscopy (SEM) and attenuated total reflectance with Fourier transform infrared (ATR-FTIR) spectroscopy. Results showed no significant colorimetric changes, or changes in the morphological properties of samples, indicating that this decontamination method can be used as an alternative treatment to eliminate insects and micro-fungi of botanical collections without the use of toxic substances.

    Palavras-Chave: gamma radiation; cultural objects; cultural objects; decontamination; preservation; plants; herbs; absorbed radiation doses; radiation effects

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

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

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

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

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

Exemplo:

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

Autor: Maprelian

Título: loss of coolant

Tipo de publicação: Texto completo de evento

Ano de publicação: 2015

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

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

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

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

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

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

ATENÇÃO!

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

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

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

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


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

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.