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Symposium on Nanotechnology General Session - 225th ECS Meeting

作者： Medeiros, A.L. Martinelli, A.E. Melo, D.M.A. Orlandi, M.O. Macedo, D.A. Materials Science and Engineering Postgraduate Program UFRN Natal59072-970 Brazil Institute of Chemistry UNESP Araraquara14801-907 Brazil Department of Materials Engineering UFPB João Pessoa58051-900 Brazil

ISBN: (纸本)9781607685869

CeO2-based materials doped with rare earth (TR+3) can be used as alternative to traditional NiO-YSZ anodes in solid oxide fuel cells as they have higher ionic conductivity and lower ohmic losses compared to YSZ. Moreover, they allow fuel cell operation at lower temperatures (500-800°C). In the anode composition, the concentration of NiO acting as catalyst in YSZ provides high electrical conductivity and high electrochemical activity of reactions, promoting internal reform in the cell. In this work, NiO - Ce1-xEuxO2-δ compounds (x = 0.1, 0.2 and 0.3) have been synthesized by microwave-assisted hydrothermal method. The materials were characterized by TG, XRD, TPR and SEM-FEG techniques. The refinement of data obtained by X-ray diffraction showed the presence of ceria doped with europium crystallized in a cubic phase with fluorite structure, in addition to the presence of NiO. The microwaveassisted hydrothermal method showed significant reduction in the average particle size and good mass control of phase compositions compared to other chemical synthesis techniques. © The Electrochemical Society.

关键词： Nickel oxide

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Electrical properties of lanthanum silicate apatite electrolytes prepared by an innovative chemical route

Electrical properties of lanthanum silicate apatite electrol...

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Symposium on Nanotechnology General Session - 225th ECS Meeting

作者： Macedo, G.L.S. Macedo, D.A. Rajesh, S. Martinelli, A.E. Figueiredo, F.M.L. Marques, F.M.B. Nascimento, R.M. Department of Chemical Engineering UFRN Natal59078-970 Brazil Department of Materials Engineering UFPB João Pessoa58051-900 Brazil Dept. of Materials and Ceramic Eng. CICECO University of Aveiro 3810-193 Portugal Materials Science and Engineering Postgraduate Program UFRN 59078-970 Brazil

ISBN: (纸本)9781607685869

This work reports the synthesis of apatite-type lanthanum silicate powders with nominal composition La10Si6O27 by an innovative chemical route which combines co-precipitation and sol-gel approaches. The herein proposed synthetic procedure is advantageous in reducing energy consumption and processing time, key elements to decrease the total manufacturing cost. The asprepared powder was calcined between 500 and 900 °C. Structure of the calcined powders, characterized by X-ray diffraction (XRD) and Rietveld refinement, indicated the formation of apatite crystalline lanthanum silicate with minor amount of L2O3 at 900 °C. The apatite powder was further analyzed by scanning electron microscopy (SEM). The effect of sintering temperature, ranging from 1400 to 1450 °C, on the electrical properties was investigated by impedance spectroscopy. Electrical measurements were recorded in the 400-800 °C temperature range. The lanthanum silicate electrolyte sintered at 1450 °C exhibited total electrical conductivity (σ700 °C = 2.12 × 10-3 ***-1) comparable with samples from literature prepared by sol-gel and freeze drying methods and sintered at 1500 °C. The results in the present study demonstrate that the co-precipitation method combined with a solgel approach is a promising alternative route to synthesize lanthanum silicate powders. © The Electrochemical Society.

关键词： Powders

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A flexible ultrasonic velocity profiler development environment

A flexible ultrasonic velocity profiler development environm...

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IEEE Instrumentation and Measurement Technology Conference

作者： César Yutaka Ofuchi Fabio Rizental Coutinho Raquel dos Santos Rasia Lucia Valeria Ramos de Arruda Flávio Neves Rigoberto Eleazar Melgarejo Morales Graduate School of Electrical Engineering and Computer Science (CPGEI) Federal University of Technology-Paraná (UTFPR) Curitiba Brazil Mechanical & Materials Engineering Postgraduate Program (PPGEM) Federal University of Technology-Paraná (UTFPR) Curitiba Brazil

ISBN: (纸本)9781467363846

Ultrasonic velocity profiler method is now an accepted tool in modern experimental fluid mechanics and fluid engineering. As a relative new technology, different applications and improvements of the technique are being researched over the last years. This paper presents an environment to develop new algorithms to improve the ultrasonic velocity estimation technique. The system uses the LabVIEW modular platform integrated with mathematical script language used in many signal-processing software. The phase-shift algorithm was implemented and tested using the proposed system. The results are validated with standard velocity measurements generated by a rotating cylinder.

关键词： Acoustics Velocity measurement Software Signal processing algorithms Ultrasonic variables measurement Fluids Doppler effect

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Microstructure and wear resistance of spray-formed supermartensitic stainless steel

Microstructure and wear resistance of spray-formed supermart...

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作者： Zepon, Guilherme Kiminami, Claudio Shyinti Filho, Walter José Botta Bolfarini, Claudemiro Postgraduate Program in Science and Materials Engineering Federal University of São Carlos - UFSCar São Carlos SP Brazil Department of Materials Engineering Federal University of São Carlos - UFSCar São Carlos SP Brazil

Since the early 90's the oil industry has been encouraging the development of corrosion and wear resistant alloys for onshore and offshore pipeline applications. In this context supermartensitic stainless steel was introduced to replace the more expensive duplex stainless steel for tubing applications. Despite the outstanding corrosion resistance of stainless steels, their wear resistance is of concern. Some authors reported obtaining material processed by spray forming, such as ferritic stainless steel, superduplex stainless steel modified with boron, and iron-based amorphous alloys, which presented high wear resistance while maintaining the corrosion performance. The addition of boron to iron-based alloys promotes the formation of hard boride particles (M2B type) which improve their wear resistances. This work aimed to study the microstructure and wear resistance of supermartensitic stainless steel modified with 0.3 wt. (%) and 0.7 wt. (%) processed by spray forming (SF-SMSS 0.3%B and SF-SMSS 0.7%B, respectively). These boron contents were selected in order to improve the wear resistance of supermartensitic stainless steel through the formation of uniformly distributed borides maintaining the characteristics of the corrosion resistant matrix. SF-SMSS 0.7%B presents an abrasive wear resistance considerably higher than spray-formed supermartensitic stainless steel without boron addition (SF-SMSS). © 2013.

关键词： Wear resistance

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Thermoeconomic design and optimization of frost-free refrigerators

Thermoeconomic design and optimization of frost-free refrige...

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作者： Mitishita, Rodrigo S. Barreira, Eduardo M. Negrão, Cezar O.R. Hermes, Christian J.L. Thermal Science Laboratory Postgraduate Program of Mechanical and Materials Engineering Federal University of Technology - Paraná Av. Sete de Setembro 3165 80230901 Curitiba PR Brazil Center for Applied Thermodynamics Department of Mechanical Engineering Federal University of Paraná P.O. Box 19011 81531990 Curitiba PR Brazil

An optimization methodology aiming at energy and cost savings in frost-free refrigerators is advanced. A steady-state simulation model was devised and its predictions for energy consumption were compared with experimental data obtained elsewhere, with differences not exceeding a +/- 9% error band. The model was used to find out the evaporator air flow rate, the number of evaporator and condenser fins, the compressor size and efficiency, and the insulation thicknesses of both fresh- and frozen-food compartments which yield the minimum energy consumption when the total cost is constrained. The optimization led to a refrigeration system with energy consumption 18% lower than that observed for the baseline system without any cost penalty. The system performance for four different compressors, including a high efficiency, a large capacity and a variable-speed one, was also analyzed. For the refrigerator under analysis, it was found that, to ensure an economically feasible design, the variable-speed compressor should not cost 26% more than a single-speed one with the same piston displacement. © 2012 Elsevier Ltd. All rights reserved.

关键词： Compressors

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Thermoeconomic analysis and optimization of residential split-type air conditioners

Thermoeconomic analysis and optimization of residential spli...

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作者： Barreira, Eduardo M. Negrão, Cezar O.R. Hermes, Christian J.L. Thermal Science Laboratory Postgraduate Program of Mechanical and Materials Engineering Federal University of Technology - Paraná Av. Sete de Setembro 3165 80230-901 Curitiba PR Brazil Center for Applied Thermodynamics Department of Mechanical Engineering Federal University of Paraná P.O. Box 19011 81531-990 Curitiba PR Brazil

A simulation-based optimization methodology for designing unitary residential air conditioners with focus on both energy performance enhancement and cost savings is presented. A steady-state system simulation model was put forward for a 2.5-ton nominal cooling capacity split-type air conditioning unit operating with R-410A as the working fluid. The model predictions for cooling capacity, sensible heat ratio (SHR) and coefficient of performance (COP) were compared with experimental data, when it was found that the model is able to predict the experimental trends within a ±6% error band. The model was then used to find out the condenser and evaporator geometries (face area, heat transfer area) that enhance the system COP for a fixed cost. On one hand, it was observed that the COP can be increased by 7% if the cost is held fixed. On the other hand, cost savings of 33% were achieved when the system COP was held constant. © 2012 Elsevier Ltd. All rights reserved.

关键词： Air conditioning

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Low temperature solvolthermally synthesized nitrogen-fluorine doped TiO2 for methyl orange photodegradation

Low temperature solvolthermally synthesized nitrogen-fluorin...

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2012 2nd International Conference on Key engineering materials, ICKEM 2012

作者： Kwamman, Tanagorn Smith, Siwaporn Meejoo Materials Science and Engineering Postgraduate Program Faculty of Science Mahidol University 272 Rama VI Road Ratchathevi Bangkok 10400 Thailand Department of Chemistry Center of Excellence for Innovation in Chemistry Mahidol University 272 Rama VI Road Ratchathevi Bangkok 10400 Thailand

ISBN: (纸本)9783037853825

A low temperature solvothermal method was employed to synthesize nitrogen-fluorine doped TiO2 materials (N/F -TiO2) at various mole ratio of Ti:F;10:1, 10:0.3 and 10:0.1, for photocatalytic applications. Doping fluorine and nitrogen in the TiO2 structure extend the spectra response of the materials toward a visible region resulting in the high efficiency to oxidize methyl orange (MO) under UV-Vis irradiation. The microstructure and photocatalytic activity of the materials appeared to depend on titanium precursors, titanium isopropoxide (TTIP) or tetrabutyl orthotitanate (TBOT), and the concentration of dopant (NH4F). The highest MO decolorization efficiency under UV-Vis irradiation for 30 minutes is about 86 % by using N-F-TiO2 (TTIP precursor) with Ti: F of 10: 3 as catalyst. The decolorization efficiencies of MO over N-F-TiO2 materials (TTIP precursor) are twice higher than that of the undoped catalyst. © (2012) Trans Tech Publications.

关键词： Titanium dioxide

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Characteristics of Leachate at Sukawinatan Landfill, Palembang, Indonesia

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Journal of Physics: Conference Series 2013年第1期423卷

作者： Eka Sri Yusmartini Dedi Setiabudidaya Ridwan Marsi Faizal PhD Candidate Postgraduate Program Sriwijaya University Indonesia Department of Physics Faculty of Mathematics and Science Sriwijaya University Indonesia Nuclear Industrial Materials Technology Centre Serpong Indonesia Faculty of Agriculture Sriwijaya University Indonesia Department of Chemical Engineering Faculty of Engineering Sriwijaya University Indonesia

Landfill (TPA) Sukawinatan Palembang is an open dumping system which covers an area of 25 hectares. This system may bring an environmental damage to the surrounding area because it does not provide leachate treatment. Leachate is the landfill waste that dissolves many compounds that contain pollutants from both organic substances and heavy metal origin. This paper presents the results of laboratory analysis on samples of leachate as well as shallow groundwater from the surrounding area. The results were compared to established quality standards to evaluate whether the leachate has influenced the quality of the shallow groundwater in the surrounding area. The results show that there are some indications that the quality of groundwater has been polluted by the leachate of both organic substances and heavy metals produced by the Sukawinatan landfill.

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Lanthanum Manganite and Cobaltite-based Composite Cathodes for SOFCs

Lanthanum Manganite and Cobaltite-based Composite Cathodes f...

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2012 International Conference on Power and Energy Systems(ICPES 2012)

作者： Daniel A.Macedo Moisés R.Cesário Beatriz Cela Carlos A.Paskocimas Dulce M.A.Melo Rubens M.Nascimento Antonio.E.Martinelli Materials Science and Engineering Postgraduate Program UFRN 59072-97 Natal/RN Brazil Chemistry Postgraduate Program UFRN 59072-970 Natal/RN Brazil Forschungszentrum Jülich GmbH Central Department of Technology (ZAT) Jülich Germany

The development of novel high-performance cathodes is essential to reduce Solid Oxide Fuel Cell (SOFCs) operation to low and intermediate temperatures. To that end, the performance of CeO 2 -based composite cathodes is very attractive. In the present work, LSM (La0.8 Sr0.2 MnO3 ), LSCF (La0.5Sr0.5Co0.8Fe0.2O3 ) and SDC (Ce0.8Sm0.2O1.9 ) powders were synthesized by different synthesis methods and used to prepare SOFC composite film cathodes. LSM-SDC and LSCF-SDC composite powders were obtained by milling. Composite films were deposited onto yttria stabilized zirconia (YSZ) electrolytes and characterized by scanning electron microscopy. Preliminary performance tests were carried out using a single cell having a LSCF-SDC cathode. I-V curves indicated that the cell had qualitatively good performance with maximum power density of 19 mW/cm 2 at 800℃. The preparation of LSM and LSCF composites by mixing SDC, synthesized by the method proposed herein is an innovative alternative for the production of high performance ceramic materials for SOFC cathodes.

关键词： Modified Pechini Method, Microwave-assisted Combustion, Composite materials, SOFC cathodes.

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Using sugar cane bagasse ash into clay products

Journal of Solid Waste Technology and Management

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Journal of Solid Waste Technology and Management 2012年第1期38卷 5-10页

作者： Acchar, Wilson Paranhos, Raimundo Jorge Santos Physics Department Federal University of Rio Grande Do Norte Natal-RN 59072-970 Brazil Postgraduate Program of Science and Materials Engineering University of Rio Grande Do Norte Natal-RN 59072-970 Brazil

The agro and industrial activities are currently responsible for the production of large amounts of solid wastes. The use of industrial wastes such as granite, marble, kaolin and pegmatite and agro-industrial rejects into clay products has been widely developed over the last few decades. Clay materials used in the ceramic industry exhibit a large diversification of compositions that al-low the addition of different types of waste materials to the clay mixture. Sugar cane bagasse ash (SCBA), a by-product of the sugar process, is exacerbating the environmental problem. Bra-zil produces an enormous amount of sugar and the lack of adequate landfill areas available for disposal of sugar cane bagasse ash rejects poses a critical problem for the agro-industry. This work describes, for the first time, research carried out on the manufacturing of ceramic tile mate-rials with sugar cane bagasse ash additions. SCBA, consisting basically of potassium oxide, was added to the clay formulations as an alternative to feldspar. Clay with different sugar cane ba-gasse ash content was mixed and sintered. Sintered specimens were characterized by X-ray dif-fraction, density, porosity, thermal analysis and strength measurements. The results obtained showed that the sugar cane ash residue can be added to clay materials as an alternative to feld-spar, without degrading their properties.

关键词： Sintering

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