Brazilian Nuclear Energy Research Institute (IPEN)

Sao Paulo, Brazil

Brazilian Nuclear Energy Research Institute (IPEN)

Sao Paulo, Brazil
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Agency: European Commission | Branch: FP7 | Program: CP-IP-SICA | Phase: ENV.2011.4.1.1-1 | Award Amount: 8.67M | Year: 2011

Today, countries use a wide variety of methods to monitor the carbon cycle and it is difficult to compare data from country to country and to get a clear global picture. The current global observational and modelling capabilities allow us to produce estimates of carbon budget at different level (from local to global) but many uncertainties still remain. Decision makers need now more than ever systematic, consistent and transparent data, information and tools for an independent and reliable verification process of greenhouse gas emissions and sinks. Therefore higher quality and quantity of CO2 and CH4 data, from different domains and with an enhanced spatial and temporal resolution, need to be collected by a globally integrated observation and analysis system. This can be obtained by the coordinated Global Carbon Observation and Analysis System that this project aims at designing, addressing the climate targets of the Group on Earth Observations (GEO) toward building a Global Earth Observation System of Systems (GEOSS) for carbon. Specific objectives of the GEOCARBON project are: Provide an aggregated set of harmonized global carbon data information (integrating the land, ocean, atmosphere and human dimension) Develop improved Carbon Cycle Data Assimilation Systems (CCDAS) Define the specifications for an operational Global Carbon Observing System Provide improved regional carbon budgets of Amazon and Central Africa Provide comprehensive and synthetic information on the annual sources and sinks of CO2 for the globe and for large ocean and land regions Improve the assessment of global CH4 sources and sinks and develop the CH4 observing system component Provide an economic assessment of the value of an enhanced Global Carbon Observing System Strengthen the effectiveness of the European (and global) Carbon Community participation in the GEO system

Wetter N.U.,Brazilian Nuclear Energy Research Institute (IPEN) | Deana A.M.,Nove de Julho University
Applied Physics B: Lasers and Optics | Year: 2014

This work demonstrates the power scalability of double-beam-mode controlling, a technique that has generated the highest optical efficiency reported so far for Nd:YLF lasers. We analyze two types of power scaling possibilities by numerical simulations: multiplication of intracavity pump modules and MOPA configuration. About 44 W of TEM00 output power at 1053 nm was experimentally demonstrated with a beam-parameter product of 1.07 × 1.15. The results show great ease of power scaling without sacrificing beam quality. © 2014, Springer-Verlag Berlin Heidelberg.

Wetter N.U.,Brazilian Nuclear Energy Research Institute (IPEN) | Deana A.M.,Nove de Julho University
Optics Express | Year: 2015

We analyze the performance of a VBG equipped diode of narrow linewidth in a side-pumped double-beam, mode-controlled resonator and demonstrate power scaling without loss of beam quality by a factor of three, when compared to previous results. 69 W of diffraction-limited laser output power at 1053 nm in a Nd:YLF lasers are demonstrated with slope efficiency of 65% and record optical-to-optical efficiency of 60%. ©2015 Optical Society of America.

Deana A.M.,Nove de Julho University | Lopez M.A.P.A.,Brazilian Nuclear Energy Research Institute (IPEN) | Wetter N.U.,Brazilian Nuclear Energy Research Institute (IPEN)
Optics Letters | Year: 2013

Efficient lasers operating in the 1.3 μm band are of interest in the health industry for frequency conversion to the visible spectral region and for Raman shifting to the eye-safe 1.5 μm region. In this work, we demonstrate for the first time, to our knowledge, a side-pumped Nd:YLiF4 laser emitting at 1.3 μm. An output power of up to 14.9 W was obtained at 1313 nm with 54 W of absorbed pump power, representing 27.7% optical efficiency and a slope efficiency of 45%. © 2013 Optical Society of America.

Wetter N.U.,Brazilian Nuclear Energy Research Institute (IPEN) | Deana A.M.,Nove de Julho University
Laser Physics Letters | Year: 2013

We present a Nd:YLiF4 diode-side-pumped resonator architecture based on a gain-guided, mode-selective technique that employs a double pass of the fundamental laser mode through the crystal. The folded cavity is very compact, robust and cost efficient. With this design we demonstrate 19 W of quasi-cw, stable diffraction-limited laser emission at 1053 nm when pumping at 792 nm with 35.4 W. The slope efficiency of the laser is 65.3% and the optical-to-optical efficiency is 53.6%, which is, to the best of our knowledge, the highest efficiency reported for Nd:YLiF4 lasers pumped into the 4F5/2 band, including longitudinal pumping schemes and lasers emitting at the higher gain line of 1047 nm. © 2013 Astro Ltd.

de Azevedo M.B.,Brazilian Nuclear Energy Research Institute (IPEN)
International journal of nanomedicine | Year: 2011

Captopril (CAP) was the first angiotensin I-converting enzyme (ACE) inhibitor to be developed and is widely used in hypertension treatment. On the other hand, cyclodextrins (CDs) are cyclic oligosaccharides whose cone-shaped cavity allows formation of noncovalent inclusion complexes with appropriately sized guest molecules, thus modifying guest physical, chemical, and biological properties. Herein, the physicochemical characterization and in vivo ACE inhibition evaluation of seven CAP/CD complexes are reported. The inclusion complexes were prepared by spray-drying, freeze-drying, kneading, or lyophilization methods and characterized by nuclear magnetic resonance, Fourier-transformed infrared spectroscopy, X-ray diffraction, differential scanning calorimetry, and scanning electron microscopy techniques. In vivo assays compared CAP and CAP/CD complex administration (0.5 mg kg(-1) or 0.09 mg kg(-1), n = 4-7) to evaluate the ACE inhibition by continuous infusion of angiotensin I (30 ng 50 μL(-1) min(-1)) in conscious Wistar rats. The physicochemical analysis demonstrated complete amorphization and complexation between CAP and CDs, indicating the substitution of water molecules inside the CD cavity with CAP. During the infusion of angiotensin I, the administration of all CAP/CD complexes induced a reduction in mean arterial pressure similar to that observed upon CAP administration. The nanoparticles obtained by the kneading method (CAP/α-CD:KM) showed a potent and long-lasting inhibitory activity (∼22 hours) on the angiotensin I pressor effect. The results suggest that the inclusion complex of CAP and α-CD can function as a novel antihypertensive formulation that may improve therapeutic use of CAP by reducing its oral dose administration to once per day, thus providing better quality of life for almost 25% of the world's population who suffer from hypertension.

Grosso R.L.,Brazilian Nuclear Energy Research Institute (IPEN) | Muccillo E.N.S.,Brazilian Nuclear Energy Research Institute (IPEN)
Journal of Power Sources | Year: 2013

The effects of the method of sintering on phase content, densification and ionic conductivity of zirconia stabilized with 10 mol% scandia and 1 mol% ceria are investigated varying dwell temperature and time. Thermodilatometry as well as sintered density results indicate a fast densification for temperatures above 1150°C. The rhombohedric phase is detected in the 1150-1300°C range depending on the sintering time. In conventionally sintered pellets, after 2 h at 1200°C the material is cubic single-phase. For this method of sintering, high dwell temperatures and prolonged times lead to phase decomposition and consequent formation of the rhombohedric phase. For any specific relative density, the mean grain size of pellets sintered by the two-stage method is smaller than the conventionally sintered ones. The smaller mean grain size obtained for specimens sintered by the two-stage method precludes an improvement in the mechanical properties. The overall electrolyte conductivity determined by impedance spectroscopy for pellets sintered by both methods exhibits similar behavior over the whole temperature range (300-800°C) of measurements. © 2013 Elsevier B.V. All rights reserved.

Muccillo R.,Brazilian Nuclear Energy Research Institute (IPEN) | Muccillo E.N.S.,Brazilian Nuclear Energy Research Institute (IPEN)
Journal of the European Ceramic Society | Year: 2013

Analyses of electrochemical impedance spectroscopy plots and dilatometric curves of ZrO2:Y2O3 (YSZ) green compacts upon sintering show the possibility of choosing the shrinkage level of the green pellet by passing a current flash through the interparticle regions. The experiments consisted on inserting a YSZ green compact in a dilatometer sample holder, connecting either to a power supply or to an impedance analyzer, and monitoring the shrinkage upon sintering with and without applying an ac voltage in the 800-1000°C temperature range. This procedure allows taking the sample from the first to the second sintering stage in few seconds without the occurrence of significant grain growth. © 2012 Elsevier Ltd.

Muccillo R.,Brazilian Nuclear Energy Research Institute (IPEN) | Muccillo E.N.S.,Brazilian Nuclear Energy Research Institute (IPEN)
Journal of the European Ceramic Society | Year: 2014

SnO2 green pellets were submitted to ac electric fields at temperatures below 1350°C. Electric current pulses occurred and a substantial modification was found in the microstructure of the pellets after application of 80Vcm-1 at 900, 1100 and 1300°C. Similar experiments were carried out in SnO2 mixed to 2wt.% MnO2. The linear shrinkage of the pellets was monitored with a dilatometer during the application of the electric field. Scanning electron microscopy micrographs of the pellets show the grain structure evolution after the electric current pulses. The larger is the electric current flow through the SnO2 pellet, the larger are the shrinkage and the average grain size. Even though sintering occurs without significant densification in SnO2, the welding of the grains is evident. The apparent density of green pellets of SnO2 with MnO2 addition sintered at 1100°C increased 110% with the application of 80Vcm-1, 5A. © 2013 Elsevier Ltd.

Goncalves M.D.,Brazilian Nuclear Energy Research Institute (IPEN) | Muccillo R.,Brazilian Nuclear Energy Research Institute (IPEN)
Ceramics International | Year: 2014

Polycrystalline powders of yttrium-doped barium zirconate with nominal composition BaZr0.9Y0.1O3-δ (BZY10) were synthesized by the oxidant-peroxo (OP) method using hexahydrated yttrium nitrate, barium nitrate and hydrated zirconyl nitrate. This is an environmental friendly method, free of common contaminants such as carbon graphite or halides, and promotes the formation of stoichiometric powders composed by sinteractive nanoparticles. The powders were amorphous and required a heat treatment to crystallize the perovskite phase. The powders were characterized by thermogravimetry and differential thermal analysis, X-ray fluorescence spectroscopy, X-ray diffraction, evaluation of specific surface area by inert gas adsorption, scanning electron microscopy and electrochemical impedance spectroscopy. Stoichiometric single perovskite BZY10 powders were successfully synthesized. Carbonate ions, adsorbed during the powder synthesis, are fully decomposed after calcination at 1200 C. The powders consist of agglomerate reactive nanosized particles. Pressing the powders to pellets and sintering at 1600 C yielded relative density higher than 91% of the theoretical density. Scanning electron microscopy images of chemically and thermally etched surfaces clearly defines two regions: one dense with grains of irregular shapes and average submicron size, and another porous. The impedance spectroscopy analysis shows that sintered pellets prepared with OP powders have higher electrical conductivity than pellets using powders obtained by solid state reaction. © 2013 Elsevier Ltd and Techna Group S.r.l. All rights reserved.

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