Abstract: We analyze satellite retrievals of carbon monoxide from the MOPITT (Measurements of Pollution in the Troposphere) instrument over the Amazon Basin, focusing on the MOPITT Version 6 “multispectral” retrieval product (exploiting both thermal-infrared and near-infrared channels). Validation results based on in situ vertical profiles measured between 2010 and 2013 are presented for four sites in the Amazon Basin. Results indicate a significant negative bias in retrieved lower-tropospheric CO concentrations. The possible influence of smoke aerosol as a source of retrieval bias is investigated using collocated Aerosol Robotic Network (AERONET) aerosol optical depth (AOD) measurements at two sites but does not appear to be significant. Finally, we exploit the MOPITT record to analyze both the mean annual cycle and the interannual variability of CO over the Amazon Basin since 2002.

Palavras-Chave: validation; carbon monoxide; brazil; satellites; pollution; troposphere; measuring instruments

DEETER, M.N.; MARTINEZ-ALONSO, S.; GATTI, L.V.; GLOOR, M.; MILLER, J.B.; DOMINGUES, L.G.; CORREIA, C.S.C. Validation and analysis of MOPITT CO observations of the Amazon Basin. Atmospheric Measurement Techniques, v. 9, n. 8, p. 3999-4012, 2016. DOI: 10.5194/amt-9-3999-2016. Disponível em: http://repositorio.ipen.br/handle/123456789/26809. Acesso em: $DATA.

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Abstract: This study reports the use of PtAu/C electrocatalysts with different atomic ratios (90:10, 70:30 and 50:50) supported on Vulcan XC 72 carbon and prepared by the sodium borohydride method toward formate electrooxidation in alkaline media. The materials were characterized by X-ray diffraction, showing peaks characteristics of Pt and Au face-centered-cubic structures, and also by transmission electron micrographs that show the nanoparticles well dispersed on carbon and a mean particle size between 4 and 5 nm for all electrocatalysts. Electrochemical experiments show PtAu/C as promising catalysts toward formate oxidation, while single cell experiments reveal PtAu/C 90:10 as the best material since it provides a power density higher than Pt/C. The incorporation of Au could increase formate oxidation for more than one reason: (i) a facilitated rupture of C–H bond; (ii) the Au/oxide interface or (iii) by regenerating active sites.

Palavras-Chave: electrocatalysts; platinum; gold; carbon; formate fuel cells; borohydrides; oxidation; electrochemistry

SILVA, SIRLANE G. da; SILVA, JULIO C.M.; BUZZO, GUILHERME S.; NETO, ALMIR O.; ASSUMPÇAO, MONICA H.M.T. Use of PtAu/C electrocatalysts toward formate oxidation: electrochemical and fuel cell considerations. Materials for Renewable and Sustainable Energy, v. 5, n. 15, p. 1-8, 2016. DOI: 10.1007/s40243-016-0079-8. Disponível em: http://repositorio.ipen.br/handle/123456789/27008. Acesso em: $DATA.

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Abstract: Thorium is nearly three times more abundant than uranium in the Earth’s crust. Some papers evaluate the thorium resources in Brazil over 1,200,000 metric t. These figures mean that the country is probably the biggest thorium resource in the world, with only part of the territory prospected. Nevertheless, Brazil has not a research program for use of thorium in nuclear reactors, even having dedicated special attention to the subject in the beginning of its nuclear activities, in the fifties and sixties. From 1985 until 2003 IPEN operated a pilot plant for thorium nitrate production and purification, used by Brazilian industry for production of gas mantles. This facility produced over 170 metric t of thorium nitrate. Despite the non-nuclear application, the pilot plant was unique in the southern hemisphere. On the other hand, Brazil has the biggest world niobium resources. The Brazilian thorium and niobium resources added to the predictable future importance of alternative fissile materials have motivated this research, since uranium is a finite resource if used in the present thermal nuclear reactors. Besides this, thorium oxide is an important nuclear reactor material. It is a refractory oxide and its ceramic fabrication process involves a very high temperature sintering treatment considering that thoria melting point is very high (3,650 K). Cations of elements of the group VB (V, Nb and Ta) have a known effect in the reduction of thoria sintering temperature. IPEN has initiated an investigation about the use of niobium as a dopant for thoria sintering temperature reduction. The thoria used in the research was produced in the IPEN’s pilot plant and different amounts of niobium oxide (Nb2O5) will be added to thoria by different routes. The powders will be compressed and the compacted pellets will be sintered at different temperatures. The influence of the different parameters in the density of sintered pellets is being investigated. This paper presents the chemical and physical characterization for the thoria used in the investigation.

Palavras-Chave: chemical analysis; density; historical aspects; niobium oxides; nuclear fuels; pellets; reduction; sintering; temperature range 0400-1000 k; thorium; brazilian cnen

TAKIISHI, HIDETOSHI; GENOVA, LUIS A.; CAVALHEIRA, ELTON D.; COTRIM, MARYCEL B.; SANTOS, WILSON; LAINETTI, PAULO E.O. Use of dopants for thoria sintering temperature reduction-characterization of THO2. Journal of Energy and Power Engineering, v. 10, n. 12, p. 740-745, 2016. DOI: 10.17265/1934-8975/2016.12.004. Disponível em: http://repositorio.ipen.br/handle/123456789/27158. Acesso em: $DATA.

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Abstract: Since the inception of its proficiency test program to evaluate radionuclide measurement in hospitals and clinics, the National Metrology Laboratory of Ionizing Radiation-LNMRI, that represents Brazilian National Metrology Institute (NMI) for ionizing radiation has expanded its measurement and calibration capability. Requirements from the National Health Surveillance Agency from Ministry of Health (ANVISA), to producers of radiopharmaceuticals provided an opportunity to improve the full traceability chain to the highest level. Fluorodeoxyglucose (FDG-18F) is the only radiopharmaceutical simultaneously produced by all Brazilian radiopharmaceutical production centers (RPCs). By running this proficiency test, LNMRI began to provide them with the required traceability. For evaluation, the ratio of RPC to reference value results and ISO/IEC17043:2010 criteria were used. The reference value established as calibration factor on the secondary standard ionization chamber was obtained from three absolute measurements systems, and routinely confirmed in each round of proficiency test by CIEMAT/NIST liquid scintillation counting. The γ-emitting impurities were checked using a High-Purity Germanium (HPGe) detector. The results show that Brazilian RPCs are in accordance with (accuracy within 710%) the Brazilian standard for evaluation of measurements with radionuclide calibrators (CNEN NN 3.05., 2013). Nevertheless, the RPCs should improve the methodology of uncertainty estimates, essential when using the statistical criteria of ISO/IEC 17043 standard, in addition to improving accuracy to levels consistent with their position in the national traceability chain

Palavras-Chave: activity meters; calibration; comparative evaluations; international electrotechnical commission; iso; nuclear medicine; radiation metrology; radiopharmaceuticals; recommendations; security; brazil

OLIVEIRA, A.E.; IWAHARA, A.; SILVA, C.J.; CRUZ, P.A.L.; POLEDNA, R.; SILVA, R.L.; LARANJEIRA, A.S.; DELGADO, J.U.; TAUHATA, L.; LOUREIRO, J.S.; TOLEDO, B.C.; BRAGHIROLLI, A.M.S.; ANDRADE, E.A.L.; SILVA, J.L.; HERNANDES, H.O.K.; VALENTE, E.S.; DALLE, H.M.; ALMEIDA, V.M.; SILVA, T.G.; FRAGOSO, M.C.F.; OLIVEIRA, M.L.; NASCIMENTO, E.S.S.; OLIVEIRA, E.M.; HERRERIAS, R.; SOUZA, A.A.; BAMBALAS, E.; BRUZINGA, W.A. Traceability from governamental producers of radiopharmaceuticals in measuring 18F in Brazil. Applied Radiation and Isotopes, v. 109, p. 236-241, 2016. DOI: 10.1016/j.apradiso.2015.11.051. Disponível em: http://repositorio.ipen.br/handle/123456789/27188. Acesso em: $DATA.

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Abstract: Vertical distribution of some rare earth elements (REEs) and trace elements through a Jurumirim Reservoir sediment core is presented. REE fractionation using BCR sequential extraction protocol was performed to verify REE mobility in the environment. Three steps (exchangeable, reducible, oxidizable) and residual fractions were studied and REE distribution for each was evaluated by ICP-MS. REEs showed a higher affinity for the reducible phase. Instrumental neutron activation analysis was also applied to sediment samples to determine the total mass fraction for some REE (Ce, Eu, La, Lu, Nd, Sm, Tb, and Yb). The diagrams normalized to chondrite values were used for a REE distribution pattern evaluation.

Palavras-Chave: distribution; elements; fractionation; icp mass spectroscopy; neutron activation analysis; particle mobility; rare earths; sediments; water reservoirs; brazil

FRANKLIN, R.L.; SILVA, S.A.; FAVARO, D.I.T.; LUIZ-SILVA, W. Trace and some rare earth elements distribution in a sediment profile from Jurumirim Reservoir, São Paulo State, Brazil: total content and extracted phases. Journal of Radioanalytical and Nuclear Chemistry, v. 309, n. 1, p. 439-451, 2016. DOI: 10.1007/s10967-016-4785-6. Disponível em: http://repositorio.ipen.br/handle/123456789/26807. Acesso em: $DATA.

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Abstract: Thorium was discovered in 1828 by the Swedish chemist Jons J. Berzelius. Despite some advantages over uranium for use in nuclear reactors, its main use, in the almost two centuries since its discovery, thorium was restricted to use for gas mantles, especially in the early 20th century. In the beginning of the nuclear era, many countries had interested on thorium, particularly during the 1950-1970 period. There are about 435 nuclear reactors in the world nowadays. They need more than 65,000 tons of uranium yearly. The future world energy needs will increase and, even if we assumed a conservative contribution of nuclear generation, there will be a significant increasing in the uranium prices occur, taking into account that uranium, as used in the present thermal reactors, is a finite resource. Thorium is nearly three times more abundant than uranium in the Earth’s crust. Despite thorium is not a fissile material, 232Th can be converted to 233U (fissile) more efficiently than 238U to 239Pu. Besides this, since it is possible to convert thorium waste into non-radioactive elements, thorium is an environment-friendly alternative energy source. Thorium fuel cycle is also inherently resistant to proliferation. Some papers evaluate the thorium resources in Brazil over 1,200,000 metric t. Then, the thorium alternative must be seriously considered in Brazil for strategic reasons. In this paper a brief history of thorium is presented, besides a review of the world thorium utilization and a discussion about advantages and restrictions of thorium use.

Palavras-Chave: abundance; fertile materials; historical aspects; nuclear energy; nuclear fuels; power generation; processing; thorium

LAINETTI, PAULO E.O. Thorium and its future importance for nuclear energy generation. Journal of Energy and Power Engineering, v. 10, n. 10, p. 600-605, 2016. DOI: 10.17265/1934-8975/2016.10.003. Disponível em: http://repositorio.ipen.br/handle/123456789/27171. Acesso em: $DATA.

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Abstract: This work focuses of the influence of weathering factors UV radiation, humidity, and temperature on the structure and morphology poly(propylene) (PP) with high melt strength (HMSPP), also called poly(propylene) modified by irradiation. The HMSPP was prepared from isotactic poly(propylene) (iPP) in presence of acetylene at 110 kPa pressure and irradiated with g of 60Co at doses of 5, 12.5 and 20 kGy. It has been observed that HMSPP deteriorates in the weathering and thermal resistance, and the long-term stability of HMSPP, beyond substantial color changes. The aged samples were characterized by infrared spectroscopy (FTIR), optical microscopy (OM) and differential scanning calorimetry (DSC). The optical microscopy shows different mechanisms on thermal and artificial weathering ageing. The ageing result under elevated temperature in HMSPPs exposed surfaces follows the order: HMSPP 20>12.5>5 kGy>iPP. The intense crack formation in surface exposed justifies thermooxidative degradation.

Palavras-Chave: weathering; gamma radiation; chemical radiation effects; cobalt 60; optical microscopy; infrared spectra; aging; acetylene; calorimetry; stability; morphology; cracks; polypropylene

OLIANI, WASHINGTON L.; KOMATSU, LUIZ G.H.; LUGAO, ADEMAR B.; PARRA, DUCLERC F. Thermal ageing and accelerated weathering of HMSPP: structural and morphological studies. Macromolecular Symposia, v. 367, n. 1, p. 18-23, 2016. DOI: 10.1002/masy.201500135. Disponível em: http://repositorio.ipen.br/handle/123456789/27148. Acesso em: $DATA.

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