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Sample records for cell pemfc desenvolvimento

  1. Development of electrode-membrane-electrode assemblies for proton exchange membrane fuel cells (PEMFC) by Sieve printing; Desenvolvimento de conjuntos eletrodo-membrana-eletrodo para celulas a combustivel a membrana trocadora de protons (PEMFC) por impressao a tela

    Energy Technology Data Exchange (ETDEWEB)

    Andrade, Alexandre Bodart de

    2008-07-01

    The Sieve Printing process was studied in this work to apply the catalyst layers onto electrolytes utilized in PEMFC. Initially, 25 cm{sup 2} active area MEAs were built for comparison with others MEAs produced by the Spray technique. The two methods produced MEAs that showed current densities higher than 600 mA.cm{sup -2} at 600 mV. A scaling up study for 144 cm{sup 2} of active area MEAs was carried out. For this purpose, a new cell had to be projected for shelter the MEAs in such dimensions. The profile of the gas distribution channels was developed through the computational fluid dynamic tool 'Comsol Multiphysics'. For the design of the bipolar plates of the cell the 'Auto CAD' was used. The 144 cm{sup 2} MEAs made by Spray and by Sieve Printing methods were confronted with commercials MEAs ones of equal dimensions. These commercials MEAs presented better performance at 600 mV, however they were more costly than the solution developed in this study. The new method was showed to be adequate to fabricate low cost MEAs of different geometries and to produce any amount of MEAs for small scale stacks (up to 10 kW). (author)

  2. Analysis performance of proton exchange membrane fuel cell (PEMFC)

    Science.gov (United States)

    Mubin, A. N. A.; Bahrom, M. H.; Azri, M.; Ibrahim, Z.; Rahim, N. A.; Raihan, S. R. S.

    2017-06-01

    Recently, the proton exchange membrane fuel cell (PEMFC) has gained much attention to the technology of renewable energy due to its mechanically ideal and zero emission power source. PEMFC performance reflects from the surroundings such as temperature and pressure. This paper presents an analysis of the performance of the PEMFC by developing the mathematical thermodynamic modelling using Matlab/Simulink. Apart from that, the differential equation of the thermodynamic model of the PEMFC is used to explain the contribution of heat to the performance of the output voltage of the PEMFC. On the other hand, the partial pressure equation of the hydrogen is included in the PEMFC mathematical modeling to study the PEMFC voltage behaviour related to the input variable input hydrogen pressure. The efficiency of the model is 33.8% which calculated by applying the energy conversion device equations on the thermal efficiency. PEMFC’s voltage output performance is increased by increasing the hydrogen input pressure and temperature.

  3. Development and testing of the proton exchange membrane fuel cell (PEMFC) for stationary generation; Desenvolvimento e ensaios de uma celula a combustivel de polimero solido (PEMFC) para geracao estacionaria

    Energy Technology Data Exchange (ETDEWEB)

    Ellern, Mara; Boccuzzi, Cyro Vicente [ELETROPAULO, Sao Caetano, SP (Brazil)], e-mail: mara.ellern@aes.com; Ett, Gerhard; Saiki, Gerson Yukio; Janolio, Gilberto [ELECTROCELL, Sao Paulo, SP (Brazil); Jardini, Jose Antonio [Universidade de Sao Paulo (USP), SP (Brazil)

    2004-07-01

    PEM (Proton Exchange Membrane) fuel cell uses a simple chemical reaction to combine hydrogen and oxygen into water, producing electric current in the process. It works something like reversed electrolysis: at the anode, hydrogen molecules give up electrons, forming hydrogen ions (this process is made possible by the platinum catalyst). The proton exchange membrane allows protons to flow through, but not electrons. As a result, the hydrogen ions flow directly through the proton exchange membrane to the cathode, while the electrons flow through an external circuit. As they travel to the cathode through the external circuit, the electrons produce electrical current. At the cathode, the electrons and hydrogen ions combine with oxygen to form water. In a fuel cell, hydrogen's natural tendency to oxidize and form water produces electricity and useful work. No pollution is produced and the only byproducts are water and heat. The huge advance on materials development combined with the growth demand of lower impact on environment is placing the fuel cells on the top of the most promising technologies world-wide. They are becoming in medium term feasible alternatives for energy generators up to energy plants of few MW. (author)

  4. Modelling and validation of Proton exchange membrane fuel cell (PEMFC)

    Science.gov (United States)

    Mohiuddin, A. K. M.; Basran, N.; Khan, A. A.

    2018-01-01

    This paper is the outcome of a small scale fuel cell project. Fuel cell is an electrochemical device that converts energy from chemical reaction to electrical work. Proton Exchange Membrane Fuel Cell (PEMFC) is one of the different types of fuel cell, which is more efficient, having low operational temperature and fast start up capability results in high energy density. In this study, a mathematical model of 1.2 W PEMFC is developed and simulated using MATLAB software. This model describes the PEMFC behaviour under steady-state condition. This mathematical modeling of PEMFC determines the polarization curve, power generated, and the efficiency of the fuel cell. Simulation results were validated by comparing with experimental results obtained from the test of a single PEMFC with a 3 V motor. The performance of experimental PEMFC is little lower compared to simulated PEMFC, however both results were found in good agreement. Experiments on hydrogen flow rate also been conducted to obtain the amount of hydrogen consumed to produce electrical work on PEMFC.

  5. Development of a membrane electrode as assembly production process for proton exchange membrane fuel cell (PEMFC) by sieve printing; Desenvolvimento de processo de producao de conjuntos eletrodo-membrana-eletrodo para celulas a combustivel baseadas no uso de membrana polimerica conditora de protons (PEMFC) por impressa a tela

    Energy Technology Data Exchange (ETDEWEB)

    Bonifacio, Rafael Nogueira

    2010-07-01

    Energy is a resource that presents historical trend of growth in demand. Projections indicate that future energy needs will require a massive use of hydrogen as fuel. The use of systems based on the use of proton exchange membrane fuel cell (PEMFC) has features that allow its application for stationary applications, automotive and portable power generation. The use of hydrogen as fuel for PEMFC has the advantage low pollutants' emission, when compared to fossil fuels. For the reactions in a PEMFC is necessary to build membrane electrode assembly (MEA). And the production of MEAs and its materials are relevant to the final cost of k W of power generated by systems of fuel cell. This represent currently a technological and financial barriers to large-scale application of this technology. In this work a process of MEAs fabrication were developed that showed high reproducibility, rapidity and low cost by sieve printing. The process of sieve printing and the ink composition as a precursor to the catalyst layer were developed, which allow the preparation of electrodes for MEAs fabrication with the implementation of the exact catalyst loading, 0.6 milligrams of platinum per square centimeters (mgPt.cm{sup -2}) suitable for cathodes and 0.4 mgPt.cm{sup -2} for anode in only one application step per electrode. The ink was developed, produced, characterized and used with similar characteristics to ink of sieve printing build for other applications. The MEAs produced had a performance of up to 712 m A.cm{sup -2} by 600 mV to 25 cm{sup 2} MEA area. The MEA cost production for MEAs of 247.86 cm{sup 2}, that can generate 1 kilowatt of energy was estimated to US$ 7,744.14 including cost of equipment, materials and labor. (author)

  6. Polymers application in proton exchange membranes for fuel cells (PEMFCs)

    Science.gov (United States)

    Walkowiak-Kulikowska, Justyna; Wolska, Joanna; Koroniak, Henryk

    2017-07-01

    This review presents the most important research on alternative polymer membranes with ionic groups attached, provides examples of materials with a well-defined chemical structure that are described in the literature. Furthermore, it elaborates on the synthetic methods used for preparing PEMs, the current status of fuel cell technology and its application. It also briefly discusses the development of the PEMFC market.

  7. Study and development of membrane electrode assemblies for Proton Exchange Membrane Fuel Cell (PEMFC) with palladium based catalysts; Estudo e desenvolvimento de conjuntos membrana-eletrodos (MEA) para celula a combustivel de eletrolito polimerico condutor de protons (PEMFC) com eletrocatalisadores a base de paladio

    Energy Technology Data Exchange (ETDEWEB)

    Bonifacio, Rafael Nogueira

    2013-07-01

    PEMFC systems are capable of generating electricity with high efficiency and low or no emissions, but durability and cost issues prevent its large commercialization. In this work MEA with palladium based catalysts were developed, Pd/C, Pt/C and alloys PdPt/C catalysts with different ratios between metals and carbon were synthesized and characterized. A study of the ratio between catalyst and Nafion Ionomer for formation of high performance triple-phase reaction was carried out, a mathematical model to implement this adjustment to catalysts with different relations between metal and support taking into account the volumetric aspects of the catalyst layer was developed and then a study of the catalyst layer thickness was performed. X-ray diffraction, Transmission and Scanning Electron Microscopy, X-ray Energy Dispersive, Gas Pycnometry, Mercury Intrusion Porosimetry, Gas adsorption according to the BET and BJH equations, and Thermo Gravimetric Analysis techniques were used for characterization and particle size, specific surface areas and lattice parameters determinations were also carried out. All catalysts were used on MEAs preparation and evaluated in 5 cm{sup 2} single cell from 25 to 100 °C at 1 atm and the best composition was also evaluated at 3 atm. In the study of metals for reactions, to reduce the platinum applied to the electrodes without performance losses, Pd/C and PdPt/C 1:1 were selected for anodes and cathodes, respectively. The developed MEA structure used 0,25 mgPt.cm{sup -2}, showing power densities up to 550 mW.cm{sup -2} and power of 2.2 kW{sub net} per gram of platinum. The estimated costs showed that there was a reduction of up to 64.5 %, compared to the MEA structures previously known. Depending on the temperature and operating pressure, values from US$ 1,475.30 to prepare MEAs for each installed kilowatt were obtained. Taking into account recent studies, it was concluded that the cost of the developed MEA is compatible with PEMFC stationary

  8. Propriedades físico-químicas relacionadas ao desenvolvimento de membranas de Nafion® para aplicações em células a combustível do tipo PEMFC Physicochemical properties related to the development of Nafion® membranes for application in fuel cells

    Directory of Open Access Journals (Sweden)

    Carlos E. Perles

    2008-01-01

    Full Text Available Embora não seja tecnologia recente, as células a combustível ou Fuel Cells (FC continuam recebendo grande atenção, pois são consideradas como "fontes de energia do futuro" devido a características como alto rendimento energético e baixa emissão de poluentes, permitindo a extensão o tempo de vida das reservas fósseis e contribuindo para a melhoria da qualidade de vida. Atualmente, as pesquisas estão direcionadas, principalmente, ao desenvolvimento de FC para aplicações em sistemas móveis e portáteis. De todas as tecnologias existentes, a mais promissora para essa finalidade é a célula a combustível de eletrólito polimérico, conhecida como PEMFC (Polymer Electrolyte Fuel Cell cuja pesquisa encontra-se focada, principalmente, no desenvolvimento de membranas poliméricas, com o objetivo de reduzir os custos de produção. Este trabalho será focado nos aspectos físico-químicos do desenvolvimento de membranas poliméricas. Serão discutidos aspectos estruturais do Nafion® relacionado-os as seguintes propriedades físico-químicas: fluxo eletrosmótico, permeabilidade gasosa, transporte de água através da membrana, estabilidade química e térmica. Toda a discussão será realizada para polímeros perfluorados, utilizando o Nafion® como modelo representante dessa classe de polímeros.Fuel Cells (FC continue to receive growing attention, in spite of not being a new technology, for they are considered as the "energy source of the future" owing to characteristics such as high energetic yield and low emission of pollutants. FC technology may lead to a reduction in the negative impact from energy sources on the enviroment, thus improving the quality of life and extending the lifetime of fossil combustible reserves. The mainstream of research in FC is now directed at mobile, portable systems, for which the most promising technology is the Polymer Electrolyte Fuel Cells, also known as PEMFC (Polymer Electrolyte Fuel Cell. Research

  9. Power sources involving ~ 300W PEMFC fuel cell stacks cooled by different media

    Directory of Open Access Journals (Sweden)

    Dudek Magdalena

    2017-01-01

    Full Text Available Two constructions of ~300W PEMFC stacks, cooled by different media, were analysed. An open-cathode ~300W PEMFC stack cooled by air (Horizon, Singapore and a PEMFC F-42 stack cooled by a liquid medium (Schunk, Germany were chosen for all of the investigations described in this paper. The potential for the design and construction of power sources involving fuel cells, as well as of a hybrid system (fuel cell-lithium battery for mobile and stationary applications, is presented and discussed. The impact of certain experimental parameters on PEMFC stack performance is analysed and discussed.

  10. Impact of Interfacial Water Transport in PEMFCs on Cell Performance

    International Nuclear Information System (INIS)

    Kotaka, Toshikazu; Tabuchi, Yuichiro; Pasaogullari, Ugur; Wang, Chao-Yang

    2014-01-01

    Coupled cell performance evaluation, liquid water visualization by neutron radiography (NRG) and numerical modeling based on multiphase mixture (M2) model were performed with three types of GDMs: Micro Porous Layer (MPL) free; Carbon Paper (CP) with MPL; and CP free to investigate interfacial liquid water transport phenomena in PEMFCs and its effect on cell performance. The visualized results of MPL free GDM with different wettability of bi-polar plates (BPPs) showed hydrophilic BPP improved liquid water transport at the interface between CP and channel. Numerical modeling results indicated that this difference with BPP wettability was caused by the liquid water coverage difference on CP surface. Thus, controlling liquid water coverage is the one of the key strategies for improving cell performance. Additionally, liquid water distributions across the cell for three types of GDMs were compared and significant difference in liquid water content at the interface between Catalyst Layer (CL) and GDM was observed. Numerical modeling suggests this difference is influenced by the gap at the interface and that the MPL could minimize this effect. The CP free cell (i.e. only MPL) showed the best performance and the lowest liquid water content. There were multiple impacts of interfacial liquid water transport both at CL-GDM and GDM-channel interfaces. High hydrophobicity and fine structure of MPLs contributed to enhanced liquid water transport at GDM-channel interface and as a result reduced the liquid water coverage. At the same time, MPL improves contact at the CL-GDM interface in the same manner as seen in CP with MPL case. Thus, the CP free concept showed the best performance. It is suggested that the design of the interface between each component of the PEMFC has a great impact on cell performance and plays a significant role in achievement of high current density operation and cost reduction in FCEVs

  11. The mass balance of a Proton Exchange Membrane Fuel Cell (PEMFC)

    International Nuclear Information System (INIS)

    Miloud, S.; Kamaruzzaman Sopian; Wan Ramli Wan Daud

    2006-01-01

    A Proton Exchange Membrane Fuel Cell (PEMFC), operating at low temperature uses a simple chemical process to combine hydrogen and oxygen into water, producing electric current and heat during the electrochemical reaction. This work concern on the theoretical consideration of the mass balance has been evaluated to predict the mass flow rate of the both gases (hydrogen/oxygen), the water mass balance, and the heat transfer in order to design a single cell PEMFC stack with a better flow field distributor on the performance of Polymer Electrolyte membrane fuel cells

  12. Description of gasket failure in a 7 cell PEMFC stack

    Energy Technology Data Exchange (ETDEWEB)

    Husar, Attila; Serra, Maria [Institut de Robotica i Informatica Industrial, Parc Tecnologic de Barcelona, Edifici U, C. Llorens i Artigas, 4-6, 2a Planta, 08028 Barcelona (Spain); Kunusch, Cristian [Laboratorio de Electronica Industrial Control e Instrumentacion, Facultad de Ingenieria, UNLP (Argentina)

    2007-06-10

    This article presents the data and the description of a fuel cell stack that failed due to gasket degradation. The fuel cell under study is a 7 cell stack. The unexpected change in several variables such as temperature, pressure and voltage indicated the possible failure of the stack. The stack was monitored over a 6 h period in which data was collected and consequently analyzed to conclude that the fuel cell stack failed due to a crossover leak on the anode inlet port located on the cathode side gasket of cell 2. This stack failure analysis revealed a series of indicators that could be used by a super visional controller in order to initiate a shutdown procedure. (author)

  13. A review of high-temperature polymer electrolyte membrane fuel-cell (HT-PEMFC)-based auxiliary power units for diesel-powered road vehicles

    Science.gov (United States)

    Liu, Yongfeng; Lehnert, Werner; Janßen, Holger; Samsun, Remzi Can; Stolten, Detlef

    2016-04-01

    This paper presents an extensive review of research on the development of auxiliary power units with enhanced reformate tolerance for high temperature polymer electrolyte membrane fuel cells (HT-PEMFCs). Developments in diesel reforming for fuel cells as auxiliary power units (APUs), single fuel cells and stacks and systems are outlined in detail and key findings are presented. Summaries of HT-PEMFC APU applications and start-up times for HT-PEMFC systems are then given. A summary of cooling HT-PEMFC stacks using a classic schematic diagram of a 24-cell HT-PEMFC stack, with a cooling plate for every third cell, is also presented as part of a stack analysis. Finally, a summary of CO tolerances for fuel cells is given, along with the effects of different CO volume fractions on polarization curves, the fraction of CO coverage, hydrogen coverage, anode overpotential and cell potential.

  14. Development of a membrane electrode assembly process for proton exchange membrane fuel cell (PEMFC)

    International Nuclear Information System (INIS)

    Baldo, Wilians Roberto

    2003-01-01

    In this work, a Membrane Electrode Assembly (MEA) producing process was developed, involving simple steps, aiming cost reduction and good reproducibility for Proton Exchange Membrane Fuel Cell (PEMFC) commercial applications. The electrodes were produced by spraying ink into both sides of the polymeric membrane, building the catalytic layers, followed by hot pressing of Gas Diffusion Layers (GDL), forming the MEA. This new producing method was called 'Spray and hot pressing hybrid method'. Concerning that all the parameters of spray and hot pressing methods are interdependent, a statistical procedure were used in order to study the mutual variables influences and to optimize the method. This study was earned out in two distinct steps: the first one, where seven variables were considered for the analysis and the second one, where only the variables that interfered in the process performance in the first step were considered for analysis. The results showed that the developed process was adequate, including only simple steps, reaching MEA's performance of 651 m A cm -2 at a potential of 600 mV for catalysts loading of 0,4 mg cm -2 Pt at the anode and 0,6 mg cm -2 Pt at the cathode. This result is compared to available commercial MEA's, with the same fuel cell operations conditions. (author)

  15. Channel geometric scales effect on performance and optimization for serpentine proton exchange membrane fuel cell (PEMFC)

    Science.gov (United States)

    Youcef, Kerkoub; Ahmed, Benzaoui; Ziari, Yasmina; Fadila, Haddad

    2017-02-01

    A three dimensional computational fluid dynamics model is proposed in this paper to investigate the effect of flow field design and dimensions of bipolar plates on performance of serpentine proton exchange membrane fuel cell (PEMFC). A complete fuel cell of 25 cm2 with 25 channels have been used. The aim of the work is to investigate the effect of flow channels and ribs scales on overall performance of PEM fuel cell. Therefore, geometric aspect ratio parameter defined as (width of flow channel/width of rib) is used. Influences of the ribs and openings current collector scales have been studied and analyzed in order to find the optimum ratio between them to enhance the production of courant density of PEM fuel cell. Six kind of serpentine designs have been used in this paper included different aspect ratio varying from 0.25 to 2.33 while the active surface area and number of channels are keeping constant. Aspect ratio 0.25 corresponding of (0.4 mm channel width/ 1.6mm ribs width), and Aspect ratio2.33 corresponding of (0.6 mm channel width/ 1.4mm ribs width. The results show that the best flow field designs (giving the maximum density of current) are which there dimensions of channels width is minimal and ribs width is maximal (Γ≈0.25). Also decreasing width of channels enhance the pressure drop inside the PEM fuel cell, this causes an increase of gazes velocity and enhance convection process, therefore more power generation.

  16. Development of a membrane electrode assembly production process for proton exchange membrane fuel cell (PEMFC) by sieve printing

    International Nuclear Information System (INIS)

    Bonifacio, Rafael Nogueira

    2010-01-01

    Energy is a resource that presents historical trend of growth in demand. Projections indicate that future energy needs will require a massive use of hydrogen as fuel. The use of systems based on the use of proton exchange membrane fuel cell (PEMFC) has features that allow its application for stationary applications, automotive and portable power generation. The use of hydrogen as fuel for PEMFC has the advantage low pollutants' emission, when compared to fossil fuels. For the reactions in a PEMFC is necessary to build membrane electrode assembly (MEA). And the production of MEAs and its materials are relevant to the final cost of kW of power generated by systems of fuel cell. This represent currently a technological and financial barriers to large-scale application of this technology. In this work a process of MEAs fabrication were developed that showed high reproducibility, rapidity and low cost by sieve printing. The process of sieve printing and the ink composition as a precursor to the catalyst layer were developed, which allow the preparation of electrodes for MEAs fabrication with the implementation of the exact catalyst loading, 0.6 milligrams of platinum per square centimeters (mgPt.cm -2 ) suitable for cathodes and 0.4 mgPt.cm -2 for anode in only one application step per electrode. The ink was developed, produced, characterized and used with similar characteristics to ink of sieve printing build for other applications. The MEAs produced had a performance of up to 712 mA.cm -2 by 600 mV to 25 cm 2 MEA area. The MEA cost production for MEAs of 247.86 cm 2 , that can generate 1 kilowatt of energy was estimated to US$ 7,744.14 including cost of equipment, materials and labor. (author)

  17. Catalytic hydrogen/oxygen reaction assisted the proton exchange membrane fuel cell (PEMFC) startup at subzero temperature

    Science.gov (United States)

    Sun, Shucheng; Yu, Hongmei; Hou, Junbo; Shao, Zhigang; Yi, Baolian; Ming, Pingwen; Hou, Zhongjun

    Fuel cells for automobile application need to operate in a wide temperature range including freezing temperature. However, the rapid startup of a proton exchange membrane fuel cell (PEMFC) at subfreezing temperature, e.g., -20 °C, is very difficult. A cold-start procedure was developed, which made hydrogen and oxygen react to heat the fuel cell considering that the FC flow channel was the characteristic of microchannel reactor. The effect of hydrogen and oxygen reaction on fuel cell performance at ambient temperature was also investigated. The electrochemical characterizations such as I- V plot and cyclic voltammetry (CV) were performed. The heat generated rate for either the single cell or the stack was calculated. The results showed that the heat generated rate was proportional to the gas flow rate when H 2 concentration and the active area were constant. The fuel cell temperature rose rapidly and steadily by controlling gas flow rate.

  18. Nonlinear Modeling of the PEMFC Based On NNARX Approach

    OpenAIRE

    Shan-Jen Cheng; Te-Jen Chang; Kuang-Hsiung Tan; Shou-Ling Kuo

    2015-01-01

    Polymer Electrolyte Membrane Fuel Cell (PEMFC) is such a time-vary nonlinear dynamic system. The traditional linear modeling approach is hard to estimate structure correctly of PEMFC system. From this reason, this paper presents a nonlinear modeling of the PEMFC using Neural Network Auto-regressive model with eXogenous inputs (NNARX) approach. The multilayer perception (MLP) network is applied to evaluate the structure of the NNARX model of PEMFC. The validity and accurac...

  19. PEMFC modeling and experimental validation

    Energy Technology Data Exchange (ETDEWEB)

    Vargas, J.V.C. [Federal University of Parana (UFPR), Curitiba, PR (Brazil). Dept. of Mechanical Engineering], E-mail: jvargas@demec.ufpr.br; Ordonez, J.C.; Martins, L.S. [Florida State University, Tallahassee, FL (United States). Center for Advanced Power Systems], Emails: ordonez@caps.fsu.edu, martins@caps.fsu.edu

    2009-07-01

    In this paper, a simplified and comprehensive PEMFC mathematical model introduced in previous studies is experimentally validated. Numerical results are obtained for an existing set of commercial unit PEM fuel cells. The model accounts for pressure drops in the gas channels, and for temperature gradients with respect to space in the flow direction, that are investigated by direct infrared imaging, showing that even at low current operation such gradients are present in fuel cell operation, and therefore should be considered by a PEMFC model, since large coolant flow rates are limited due to induced high pressure drops in the cooling channels. The computed polarization and power curves are directly compared to the experimentally measured ones with good qualitative and quantitative agreement. The combination of accuracy and low computational time allow for the future utilization of the model as a reliable tool for PEMFC simulation, control, design and optimization purposes. (author)

  20. Polyester synthesis for application in PEMFC type fuel cells; Sintese de poliester para aplicacao em celulas a combustivel do tipo PEM

    Energy Technology Data Exchange (ETDEWEB)

    Fiuza, R.P.; Souza, D.R. de; Fiuza, R.A.; Jose, N.M.; Boaventura, J.S. [Universidade Federal da Bahia (UFBA), Salvador, BA (Brazil). Inst. de Quimica], e-mail: raigenis@gmail.com

    2006-07-01

    The PEMFC (Proton Exchange Membrane Fuel Cell), along the SOFC (Solid Oxide Fuel Cell), is the most important technology, among the various types of fuels cell. The PEMFC shows a large versatility of applications, both for stationary and mobile use. However the PEMFC presents high manufacture cost, directly impacting in the cost of the produced energy. This work contemplates the previews sulfonation of phtalic acid and its subsequent polymerization with glycerol, using as catalytic tin dibutyl-dilaurate. The obtained material has been characterized by DSC, TGA, FTIR, MEV, DRX and XRF. The gotten results indicated that phtalic acid was sulfonated and the increase of the sulfonation degree significantly increased the crystallinity of the sulfonated ftalico acid. Furthermore, the polymer produced from the sulfonated monomer presented adequate thermal resistance and a high content of conducting groups, necessary conditions for application as electrolyte in PEMFC. All these characteristics, particularly the low cost of the reagents and the ease of production process, make the sulfonated polyester membrane a promising candidate as fuel cell electrolyte. (author)

  1. Investigations on the corrosion resistance of metallic bipolar plates (BPP) in proton exchange membrane fuel cells (PEMFC) - understanding the effects of material, coating and manufacturing

    Science.gov (United States)

    Dur, Ender

    Polymer Electrolyte Membrane Fuel Cell (PEMFC) systems are promising technology for contributing to meet the deficiency of world`s clean and sustainable energy requirements in the near future. Metallic bipolar plate (BPP) as one of the most significant components of PEMFC device accounts for the largest part of the fuel cell`s stack. Corrosion for metallic bipolar plates is a critical issue, which influences the performance and durability of PEMFC. Corrosion causes adverse impacts on the PEMFC`s performance jeopardizing commercialization. This research is aimed at determining the corrosion resistance of metallic BPPs, particularly stainless steels, used in PEMFC from different aspects. Material selection, coating selection, manufacturing process development and cost considerations need to be addressed in terms of the corrosion behavior to justify the use of stainless steels as a BPP material in PEMFC and to make them commercially feasible in industrial applications. In this study, Ti, Ni, SS304, SS316L, and SS 430 blanks, and BPPs comprised of SS304 and SS316L were examined in terms of the corrosion behavior. SS316L plates were coated to investigate the effect of coatings on the corrosion resistance performance. Stamping and hydroforming as manufacturing processes, and three different coatings (TiN, CrN, ZrN) applied via the Physical Vapor Deposition (PVD) method in three different thicknesses were selected to observe the effects of manufacturing processes, coating types and coating thicknesses on the corrosion resistance of BPP, respectively. Uncoated-coated blank and formed BPP were subjected to two different corrosion tests: potentiostatic and potentiodynamic. Some of the substantial results: 1- Manufacturing processes have an adverse impact on the corrosion resistance. 2- Hydroformed plates have slightly higher corrosion resistance than stamped samples. 3- BPPs with higher channel size showed better corrosion resistance. 4- Since none of the uncoated samples

  2. On-line and real-time diagnosis method for proton membrane fuel cell (PEMFC) stack by the superposition principle

    Science.gov (United States)

    Lee, Young-Hyun; Kim, Jonghyeon; Yoo, Seungyeol

    2016-09-01

    The critical cell voltage drop in a stack can be followed by stack defect. A method of detecting defective cell is the cell voltage monitoring. The other methods are based on the nonlinear frequency response. In this paper, the superposition principle for the diagnosis of PEMFC stack is introduced. If critical cell voltage drops exist, the stack behaves as a nonlinear system. This nonlinearity can explicitly appear in the ohmic overpotential region of a voltage-current curve. To detect the critical cell voltage drop, a stack is excited by two input direct test-currents which have smaller amplitude than an operating stack current and have an equal distance value from the operating current. If the difference between one voltage excited by a test current and the voltage excited by a load current is not equal to the difference between the other voltage response and the voltage excited by the load current, the stack system acts as a nonlinear system. This means that there is a critical cell voltage drop. The deviation from the value zero of the difference reflects the grade of the system nonlinearity. A simulation model for the stack diagnosis is developed based on the SPP, and experimentally validated.

  3. Preparation of gas diffusion layers for PEMFC fuel cells using carbon fibers; Elaboracao de uma camada de difusao de gas a partir de fibras de carbono para aplicacao em celulas combustiveis do tipo PEMFC

    Energy Technology Data Exchange (ETDEWEB)

    Santos, J.N.; Kunsti, S.R.; Malfatti, C.F. [Universidade Federal do Rio Grande do Sul - Departamento de Metalurgia (PPGEM) - Laboratorio de Pesquisa em Corrosao (LAPEC), Porto Alegre, RS (Brazil); Vargas, J.V.C. [Universidade Federal do Parana - Departamento de Engenharia Mecanica, PR (Brazil); Amico, S.C. [Universidade Federal do Rio Grande do Sul - Departamento de Materiais, RS (Brazil)

    2010-07-01

    The electrode/membrane system, called MEA, is the fundamental unit of a PEMFC (proton exchange membrane fuel cell). Within the MEA, the gas diffusion layer (GDL) is the bridge between the flow field and the catalyst layer. One of the important elements in a GDL is the substrate, typically a carbon cloth or paper, that has to be an excellent electrical conductor and show mechanical strength along with thermal and chemical stability. In this work, GDLs were produced from a suspension containing short carbon fibers in water-based polyurethane and poly(vinyl alcohol) (PVA) resins with appropriate characteristics to be used in low temperature fuel cells. The obtained GDL was characterized regarding its wettability, electrical conductivity and morphological aspects, evaluated by SEM. (author)

  4. PtM/C (M = Sn, Ru, Pd, W) based anode direct ethanol-PEMFCs: Structural characteristics and cell performance

    Energy Technology Data Exchange (ETDEWEB)

    Tsiakaras, P.E. [Department of Mechanical Engineering, School of Engineering, University of Thessaly, Pedion Areos, 38334 Volos (Greece)

    2007-09-19

    In the present work, the role of the structural characteristics of Pt-based catalysts on the single direct ethanol proton exchange membrane fuel cell (PEMFC) performance is examined. Several PtM/C (M = Sn, Ru, Pd, W) catalysts were characterized by means of transmission electron microscopy (TEM) and X-ray diffraction (XRD) and then evaluated as anode catalysts in single direct ethanol fuel cells. XRD spectra showed that Pt lattice parameter decreases with the addition of Ru or Pd and increases with the addition of Sn or W. According to the obtained experimental results, PtSn catalysts presented better electrocatalytic activity towards ethanol electro-oxidation. Based on these results, PtSn/C catalysts with different Pt/Sn atomic ratio were tested and compared. The maximum power density values obtained were correlated with the structural characteristics of the catalysts. A volcano type behaviour between the fuel cell maximum power density and the corresponding atomic percentage of Sn (Sn%) was observed. It was also observed that Sn% affects almost linearly the Pt{sub x}Sn{sub y} catalysts' lattice parameter. (author)

  5. Study and development of membrane electrode assemblies for Proton Exchange Membrane Fuel Cell (PEMFC) with palladium based catalysts

    International Nuclear Information System (INIS)

    Bonifacio, Rafael Nogueira

    2013-01-01

    PEMFC systems are capable of generating electricity with high efficiency and low or no emissions, but durability and cost issues prevent its large commercialization. In this work MEA with palladium based catalysts were developed, Pd/C, Pt/C and alloys PdPt/C catalysts with different ratios between metals and carbon were synthesized and characterized. A study of the ratio between catalyst and Nafion Ionomer for formation of high performance triple-phase reaction was carried out, a mathematical model to implement this adjustment to catalysts with different relations between metal and support taking into account the volumetric aspects of the catalyst layer was developed and then a study of the catalyst layer thickness was performed. X-ray diffraction, Transmission and Scanning Electron Microscopy, X-ray Energy Dispersive, Gas Pycnometry, Mercury Intrusion Porosimetry, Gas adsorption according to the BET and BJH equations, and Thermo Gravimetric Analysis techniques were used for characterization and particle size, specific surface areas and lattice parameters determinations were also carried out. All catalysts were used on MEAs preparation and evaluated in 5 cm 2 single cell from 25 to 100 °C at 1 atm and the best composition was also evaluated at 3 atm. In the study of metals for reactions, to reduce the platinum applied to the electrodes without performance losses, Pd/C and PdPt/C 1:1 were selected for anodes and cathodes, respectively. The developed MEA structure used 0,25 mgPt.cm -2 , showing power densities up to 550 mW.cm -2 and power of 2.2 kW net per gram of platinum. The estimated costs showed that there was a reduction of up to 64.5 %, compared to the MEA structures previously known. Depending on the temperature and operating pressure, values from US$ 1,475.30 to prepare MEAs for each installed kilowatt were obtained. Taking into account recent studies, it was concluded that the cost of the developed MEA is compatible with PEMFC stationary application

  6. Biomass gasification and fuel cells: system with PEM fuel cell; Gaseificacao de biomassa e celula a combustivel: sistema com celula tipo PEMFC

    Energy Technology Data Exchange (ETDEWEB)

    Sordi, Alexandre; Lobkov, Dmitri D.; Lopes, Daniel Gabriel; Rodrigues, Jean Robert Pereira [Universidade Estadual de Campinas (UNICAMP), Campinas, SP (Brazil). Fac. de Engenharia Mecanica], e-mail: asordi@fem.unicamp.br, e-mail: lobkov@fem.unicamp.br, e-mail: danielg@fem.unicamp.br, e-mail: jrobert@fem.unicamp.br; Silva, Ennio Peres da [Universidade Estadual de Campinas (UNICAMP), Campinas, SP (Brazil). Inst. de Fisica Gleb Wataghin], e-mail: Lh2ennio@ifi.unicamp.br

    2006-07-01

    The objective of this paper is to present the operation flow diagram of an electricity generation system based on the biomass integrated gasification fuel cell of the type PEMFC (Proton Exchange Membrane Fuel Cell). The integration between the gasification and a fuel cell of this type consists of the gas methane (CH4) reforming contained in the synthesis gas, the conversion of the carbon monoxide (CO), and the cleaning of the gaseous flow through a PSA (Pressure Swing Adsorption) system. A preliminary analysis was carried out to estimate the efficiency of the system with and without methane gas reforming. The performance was also analyzed for different gasification gas compositions, for larger molar fractions of hydrogen and methane. The system electrical efficiency was 29% respective to the lower heating value of the gasification gas. The larger the molar fraction of hydrogen at the shift reactor exit, the better the PSA exergetic performance. Comparative analysis with small gas turbines exhibited the superiority of the PEMFC system. (author)

  7. Use of Segmented Cell Operated in Hydrogen Recirculation Mode to Detect Water Accumulation in PEMFC

    OpenAIRE

    Perez, L.C.; Ihonen J.; J. M. Sousa; Adélio Mendes

    2013-01-01

    Adequate water management is crucial to increase stability and durability of Polymer Electrolyte Membrane Fuel Cells. In this paper, a test rig suitable for water balance and nitrogen crossover studies was built around a hydrogen-air segmented cell and used to indirectly assess flooding or drying conditions in specific zones of the active cell area. In particular, the anode of the segmented cell was operated in recirculation mode with continuous water removal. Current density distribution (CD...

  8. Review on the Recent Developments of Photovoltaic Thermal (PV/T and Proton Exchange Membrane Fuel Cell (PEMFC Based Hybrid System

    Directory of Open Access Journals (Sweden)

    Zulkepli Afzam

    2016-01-01

    Full Text Available Photovoltaic Thermal (PV/T system emerged as one of the convenient type of renewable energy system acquire the ability to generate power and thermal energy in the absence of moving parts. However, the power output of PV/T is intermittent due to dependency on solar irradiation condition. Furthermore, its efficiency decreases because of cells instability at high temperature. On the other hand, fuel cell co-generation system (CGS is another technology that can generate power and heat simultaneously. Integration of PV/T and fuel cell CGS could enhance the reliability and sustainability of both systems as well as increasing the overall system performance. Hence, this paper intended to present the parameters that affect performance of PV/T and Proton Exchange Membrane Fuel Cell (PEMFC CGS. Moreover, recent developments on PV/T-fuel cell hybrid system are also presented. Based on literates, mass flow rate of moving fluid in PV/T was found to affect the system efficiency. For the PEMFC, when the heat is utilized, the system performance can be increased where the heat efficiency is similar to electrical efficiency which is about 50%. Recent developments of hybrid PV/T and fuel cell show that most of the studies only focus on the power generation of the system. There are less study on the both power and heat utilization which is indeed necessary in future development in term of operation strategy, optimization of size, and operation algorithm.

  9. Quantification of in situ temperature measurements on a PBI-based high temperature PEMFC unit cell

    DEFF Research Database (Denmark)

    Lebæk, Jesper; Ali, Syed Talat; Møller, Per

    2010-01-01

    The temperature is a very important operating parameter for all types of fuel cells. In the present work distributed in situ temperature measurements are presented on a polybenzimidazole based high temperature PEM fuel cell (HT-PEM). A total of 16 T-type thermocouples were embedded on both the an...

  10. New exergetic sustainability parameters for a PEMFC

    International Nuclear Information System (INIS)

    Adnan Midilli; Ibrahim Dincer

    2009-01-01

    This paper deals with a study on development of some new exergy based environmental and sustainability parameters for a PEMFC as a function of some technical and operational parameters. In order to use the PEMFCs in residential and portable applications, they are expected to have higher exergetic efficiency, lower exergetic destruction ratio, lower environmental impact coefficient and higher environmental benign coefficient. The results show that the environmental impact coefficient ranging from 1.832 to 3.417 decreases while the environmental benign coefficient ranging from 0.903 to 26.624 increases with a rise of exergetic efficiency under some constant operating characteristics of the cell. Thus, for practical applications of a PEMFC, environmental impact coefficient should be taken into consideration and the operating and designing conditions of cell should be selected as its environmental impact coefficient will be closer to unity. (author)

  11. Development and Validation of a Simple Analytical Model of the Proton Exchange Membrane Fuel Cell (Pemfc) in a Fork-Lift Truck Power System

    DEFF Research Database (Denmark)

    Hosseinzadeh, Elham; Rokni, Masoud

    2013-01-01

    In this study, a general proton exchange membrane fuel cell (PEMFC) model has been developed in order to investigate the balance of plant of a fork-lift truck thermodynamically. The model takes into account the effects of pressure losses, water crossovers, humidity aspects, and voltage...... management, system sensitivity to coolant inlet temperature, air and fuel stoichiometry, anode inlet pressure, stack operating conditions, etc. System efficiency and electrical power at different operating conditions are also discussed. The results show that 12–30% of stack power is allocated...

  12. Desenvolvimento de tecnologia para confecção de eletrodos e conjuntos eletrodo-membrana-eletrodo (MEA por impressão à tela para aplicação em módulos de potência de células PEMFC

    Directory of Open Access Journals (Sweden)

    Valéria Cristina Fernandes

    2012-01-01

    Full Text Available Significant functions in the Proton Exchange Membrane Fuel Cells (PEMFCs rely on Gas Diffusion Layers (GDLs, such as control the water balance in the membrane electrode assembly (MEA, allow suitable gas permeability and porosity, etc. Aware of the GDL importance in the cell performance and its great demand in scale-up projects, the fuel cell research group at Instituto de Pesquisas Energéticas e Nucleares (IPEN has developed a Sieve Printing method (innovative in Brazil as a strategic solution for producing GDL and electrodes used in high power PEMFC stacks. The method has shown to be adequate to fabricate low cost electrodes, GDLs of different dimensions and to produce any amount of MEAs for power stacks.

  13. PEMFC catalyst layers: the role of micropores and mesopores on water sorption and fuel cell activity.

    Science.gov (United States)

    Soboleva, Tatyana; Malek, Kourosh; Xie, Zhong; Navessin, Titichai; Holdcroft, Steven

    2011-06-01

    The effects of carbon microstructure and ionomer loading on water vapor sorption and retention in catalyst layers (CLs) of PEM fuel cells are investigated using dynamic vapor sorption. Catalyst layers based on Ketjen Black and Vulcan XC-72 carbon blacks, which possess distinctly different surface areas, pore volumes, and microporosities, are studied. It is found that pores <20 nm diameter facilitate water uptake by capillary condensation in the intermediate range of relative humidities. A broad pore size distribution (PSD) is found to enhance water retention in Ketjen Black-based CLs whereas the narrower mesoporous PSD of Vulcan CLs is shown to have an enhanced water repelling action. Water vapor sorption and retention properties of CLs are correlated to electrochemical properties and fuel cell performance. Water sorption enhances electrochemical properties such as the electrochemically active surface area (ESA), double layer capacitance and proton conductivity, particularly when the ionomer content is very low. The hydrophilic properties of a CL on the anode and the cathode are adjusted by choosing the PSD of carbon and the ionomer content. It is shown that a reduction of ionomer content on either cathode or anode of an MEA does not necessarily have a significant detrimental effect on the MEA performance compared to the standard 30 wt % ionomer MEA. Under operation in air and high relative humidity, a cathode with a narrow pore size distribution and low ionomer content is shown to be beneficial due to its low water retention properties. In dry operating conditions, adequate ionomer content on the cathode is crucial, whereas it can be reduced on the anode without a significant impact on fuel cell performance. © 2011 American Chemical Society

  14. The production of sulfonated chitosan-sodium alginate found in brown algae (Sargassum sp.) composite membrane as proton exchange membrane fuel cell (PEMFC)

    Science.gov (United States)

    Wafiroh, Siti; Pudjiastuti, Pratiwi; Sari, Ilma Indana

    2016-03-01

    The majority of energy was used in this period is from fossil fuel, which getting decreased in the future. The objective of this research is production and characterization of sulfonated chitosan-sodium alginate found in brown algae (Sargassum sp.) composite membrane as Proton Exchange Membrane Fuel Cell (PEMFC) for alternative energy. PEMFC was produced with 4 variations (w/w) ratio between chitosan and sodium alginate, 8 : 0, 8 : 1, 8 : 2, 8 : 4 (w/w). The production of membrane was mixed sodium alginate solution into chitosan solution and sulfonated with H2SO4 0.72 N. The characterization of the PEM was uses Modulus Young analysis, water swelling, ion exchange capacity, FTIR, SEM, DTA, methanol permeability and proton conductivity. The result of the research, showed that the optimum membrane was with ratio 8 : 2 (w/w) that the Modulus Young 8564 kN/m2, water swelling 31.86%, ion exchange capacity 1.020 meq/g, proton conductivity 8,8 × 10-6 S/cm, methanol permeability 1.90 × 10-8 g/cm2s and glass transition temperature (Tg) 100.9 °C, crystalline temperature (Tc) 227.6 °C, and the melting temperature (Tm) 267.9 °C.

  15. Mathematical model of a PEMFC using a PBI membrane

    International Nuclear Information System (INIS)

    Cheddie, Denver; Munroe, Norman

    2006-01-01

    Proton exchange membrane fuel cells (PEMFC) operating with Nafion[reg] membranes have encountered numerous problems associated with water management and CO poisoning because of their low temperature of operation. Alternative high temperature membranes have been investigated, one such membrane being polybenzimidazole (PBI). This paper presents a one dimensional mathematical model, which predicts the polarization performance of a PEMFC using a PBI membrane. Peak power densities in the same order as Nafion[reg] are predicted. Results indicate that the greatest scope for improving PBI PEMFC performance is increasing the membrane conductivity and improving the catalyst performance as it interfaces with the PBI membrane

  16. Improve the efficiency of PEMFC using neutron imaging

    International Nuclear Information System (INIS)

    Kim, Tae Joo; Shim, Chulmuu

    2010-01-01

    The water management is one of the most critical issues for PEMFC commercialization. In order to make a proper scheme for water management, the information of water distribution and behavior is very important. But the visualization is difficult due to metallic coverage. Recently, neutron imaging has joined the canon of diagnostic methods for fuel cell research and is applied worldwide with qualitative and quantitative results. In this investigation, we prepared 3-parallel serpentine single PEMFC. The active area is 250 mm 2 and channel size is 1 Χ 1 mm, respectively. Distribution and transport of water in an operating PEMFC were observed as functions of flow directions and differential pressures between anode and cathodes. This investigation was performed at BST-2, Nest. The collimation ratio is 600 and neutron fluence of BST-2 is 7.2 Χ 10 6 n/s, respectively. Neutron image was captured by A-Si detector with 1 sec expsosure time. The PEMFC has different performances for each differential pressure and flow directions. When the neutron images are compared with operating conditions, the distribution and behavior of water are different. Total water fraction is increased and then decreases as the current density increases. This situation is similar trend for the flow directions. It is shown that neutron imaging technique is powerful tool to visualize the PEMFC and the water distribution and behavior of an operating PEMFC helps improve the efficiency of PEMFC

  17. Fuel cell systems and traditional technologies. Part II: Experimental study on dynamic behavior of PEMFC in stationary power generation

    International Nuclear Information System (INIS)

    Venturelli, Lucia; Santangelo, Paolo E.; Tartarini, Paolo

    2009-01-01

    The present work is focused on electric generation for stationary applications. The dynamic behavior of a PEMFC-based system has been investigated at both constant and variable load conditions from an experimental point of view. An analysis of efficiency as a function of time has been proposed to summarize the dynamic performance; moreover, current intensity and voltage have been considered as main parameters of interest from the electric point of view. In addition, other energetic and thermodynamic parameters have been studied in this work. The experimental campaign has been carried out over four test typologies: constant load; increasing and decreasing load; random load. These tests have been planned to challenge the system with a variety of load-based cycles, in the frame of a thorough simulation of real-load conditions.

  18. Current Distribution Mapping for PEMFCs

    International Nuclear Information System (INIS)

    Lilavivat, V.; Shimpalee, S.; Van Zee, J.W.; Xu, H.; Mittelsteadt, C.K.

    2015-01-01

    A developed measurement system for current distribution mapping has enabled a new approach for operational measurements in proton exchange membrane fuel cells (PEMFCs). Currently, there are many issues with the methods to measure current distribution; some of the problems that arise are breaking up the fuel cell component and these measurements are costly. Within this field of work, there is a cost effective method and an easy technique of mapping the current distribution within a fuel cell while not disrupting reactant flow. The physical setup of this method takes a current distribution board and inserts it between an anode flow field plate and a gas diffusion layer. From this layout, the current distribution can be directly measured from the current distribution board. This novel technique can be simply applied to different fuel cell hardware. Further it also can be used in fuel cell stack by inserting multiple current distribution boards into the stack cells. The results from the current distribution measurements and the electrochemical predictions from computational fluid dynamics modeling were used to analyze water transports inside the fuel cell. This developed system can be a basis for a good understanding of optimization for fuel cell design and operation mode

  19. Desenvolvimento de processo de produção de conjuntos eletrodo-membrana-eletrodo para células a combustível baseadas no uso de membrana polimérica condutora de prótons (PEMFC por impressão a tela

    Directory of Open Access Journals (Sweden)

    Rafael Nogueira Bonifácio

    2011-01-01

    Full Text Available Proton exchange membrane fuel cell (PEMFC requires membrane electrode assemblies (MEA to generate electrical energy from hydrogen and oxygen. In this study a MEA production process by sieve printing and an ink composition were developed to produce catalyst layers of MEAs. The deposition of the exact catalyst content was possible on cathodes and anodes with only one print step. The optimal ink developed shown viscosity of 2.75 Pa s, density 1.27 g cm-3, total solid content of 33.76 % and tack of 92 U.T. The electrodes prepared in only one printing step showed higher performance than those prepared in several steps.

  20. Investigation of the prospect of energy self-sufficiency and technical performance of an integrated PEMFC (proton exchange membrane fuel cell), dairy farm and biogas plant system

    International Nuclear Information System (INIS)

    Guan, Tingting; Alvfors, Per; Lindbergh, Göran

    2014-01-01

    Highlights: • A PEMFC stack with a 40% of electrical efficiency will make the integrated PEMFC-CHP, biogas plant and dairy farm self-sufficient. • The quality of the reformate gas is good enough to support normal operation of the PEMFC-CHP. • The methane conversion rate and the content of the CH 4 in the biogas need to be balanced in order to obtain the best system performance. • Compared with a coal-fired CHP plant, the integrated system can avoid coal consumption and CO 2 emissions. - Abstract: A PEMFC fuelled with hydrogen is known for its high efficiency and low local emissions. However, the generation of hydrogen is always a controversial issue for the application of the PEMFC due to the use of fossil fuel and the possible carbon dioxide emissions. Presently, the PEMFC-CHP fed with renewable fuels, such as biogas, appears to be the most attractive energy converter–fuel combination. In this paper, an integrated PEMFC-CHP, a dairy farm and a biogas plant are studied. A PEMFC-CHP fed with reformate gas from the biogas plant generates electricity and heat to a dairy farm and a biogas plant, while the dairy farm delivers wet manure to the biogas plant as the feedstock for biogas production. This integrated system has been modelled for steady-state conditions by using Aspen Plus®. The results indicate that the wet manure production of a dairy farm with 300 milked cows can support a biogas plant to give 1280 MW h of biogas annually. Based on the biogas production, a PEMFC-CHP with a stack having an electrical efficiency of 40% generates 360 MW h electricity and 680 MW h heat per year, which is enough to cover the energy demand of the whole system while the total efficiency of the PEMFC-CHP system is 82%. The integrated PEMFC-CHP, dairy farm and biogas plant could make the dairy farm and the biogas plant self-sufficient in a sustainable way provided the PEMFC-CHP has the electrical efficiency stated above. The effect of the methane conversion rate and the

  1. Modeling and off-design performance of a 1 kWe HT-PEMFC (high temperature-proton exchange membrane fuel cell)-based residential micro-CHP (combined-heat-and-power) system for Danish single-family households

    DEFF Research Database (Denmark)

    Arsalis, Alexandros; Nielsen, Mads Pagh; Kær, Søren Knudsen

    2011-01-01

    temperatures, as compared to Nafion-based PEMFCs and therefore can be a significant candidate for cogeneration residential systems. The proposed system can provide electric power, hot water, and space heating for a typical Danish single-family household. A complete fuel processing subsystem, with all necessary......A novel proposal for the modeling and operation of a micro-CHP (combined-heat-and-power) residential system based on HT-PEMFC (High Temperature-Proton Exchange Membrane Fuel Cell) technology is described and analyzed to investigate its commercialization prospects. An HT-PEMFC operates at elevated...

  2. PEMFC for aeronautic applications: A review on the durability aspects

    Science.gov (United States)

    Dyantyi, Noluntu; Parsons, Adrian; Sita, Cordellia; Pasupathi, Sivakumar

    2017-11-01

    Proton exchange membrane fuel cells (PEMFC) not only offer more efficient electrical energy conversion, relative to on-ground/backup turbines but generate by-products useful in aircraft such as heat for ice prevention, deoxygenated air for fire retardation and drinkable water for use on-board. Consequently, several projects (e.g. DLR-H2 Antares and RAPID2000) have successfully tested PEMFC-powered auxiliary unit (APU) for manned/unmanned aircraft. Despite the progress from flying PEMFC-powered small aircraft with 20 kW power output as high as 1 000 m at 100 km/h to 33 kW at 2 558 m, 176 km/h [1, 2, 3], durability and reliability remain key challenges. This review reports on the inadequate understanding of behaviour of PEMFC under aeronautic conditions and the lack of predictive methods conducive for aircraft that provide real-time information on the State of Health of PEMFCs. -To minimize performance loss due to high altitude and inclination by adjusting cathode stoichiometric ratio. -To improve quality of oxygen-depleted air by controlling operating temperature and stoichiometric ratio. -Need to devise real time prediction methods conducive for determining PEMFC SoH in aircraft.

  3. Life cycle assessment (LCA) methodology: importance in the integration of the fuel cell technology type PEMFC (proton exchange membrane fuel cells); Metodologia da analise de ciclo de vida: importancia na insercao da tecnologia de celula a combustivel do tipo PEMFC (membrana polimerica trocadora de protons)

    Energy Technology Data Exchange (ETDEWEB)

    Fukurozaki, Sandra Harumi; Seo, Emilia Satoshi Miyamaru [Instituto de Pesquisas Energeticas e Nucleares (IPEN-CNEN/SP), Sao Paulo, SP (Brazil)). Centro de Ciencia e Tecnologia de Materiais], e-mail: shfukuro@ipen.br

    2004-07-01

    To improve the standard of society's quality of life, it is necessary to improve the quality of distributed energy and its inherent services within a sustainability process. Among different technological routes that produce more sustainable energy are the fuel cells - also known as combustible batteries. The Global Environment Facility (GEF) has identified the fuel cells as a potential technology to reduce, in the future, the effect of greenhouse gases in both developed and developing countries. Although there are various types of fuel cells, the most used technology for research studies on fuel cells is the Polymer Electrolyte Fuel Cells (FEMFC). However, economic issues - related to the high cost of the membrane's materials and of the catalysts of groups of platinum metals - are still some of the obstacles that need to be overcome for this technology to be more accessible. There are also socio-environmental aspects related to the impacts caused by the extraction, the use and the destination of these metals. Taking in consideration the challenges of complying with the demands of the market and the society as well as with the growing tendency of more rigid patterns of environmental control, the objective of the present work is to show the tool of environmental management - Life Cycle Assessment (LCA) - and its importance on the pursuit for socio-economic and environmental alternatives feasible to the recycling of the catalysts of platinum of the PEMFC. This way, it intends to collaborate to the progress of the knowledge about environmental and socio-economic subjects related to the productive process of the PEMFC. (author)

  4. Effect of catalyst distribution in the active layers of proton exchange membrane fuel cells; Effet de la distribution du catalyseur dans les couches actives de piles a combustible de type PEMFC

    Energy Technology Data Exchange (ETDEWEB)

    Bultel, Y.; Durand, R.; Ozil, P. [Ecole Nationale Superieure d' Electrochimie et d' Electrometallurgie, Lab. d' Electrochimie et de Physico-chimie des Materiaux et des Interfaces, UMR 5631, 38 - Grenoble (France); Antoine, O. [Geneva Univ., Dept. de Chimie Minerale, Analytique et Appliquee, Sciences 2 (Switzerland)

    2000-07-01

    The aim of this work is to study the influence of the distribution of the platinum catalyst in the active layers on the performances of proton exchange membrane fuel cells (PEMFC) electrodes. In the one hand, the results predicted by the classical models and those in which the active layers is modified have been compared; these results have allowed to demonstrate theoretically the effect of the discrete distribution of the platinum catalyst in the form of nano-particles. On the other hand, the influence of a distribution gradient of the platinum catalyst for porous and non-porous active layers of PEMFC cathode has been experimentally demonstrated and predicted by numerical simulations. (O.M.)

  5. Conical nano-structure arrays of Platinum cathode catalyst for enhanced cell performance in PEMFC (proton exchange membrane fuel cell)

    International Nuclear Information System (INIS)

    Khan, Aziz; Nath, Bhabesh Kumar; Chutia, Joyanti

    2015-01-01

    Conical nanostructure arrays of Pt (Platinum) as cathode catalyst are developed using a novel integrated plasma sputtering technique. The integration method involves successive deposition of Pt catalyst arrays one upon another maintaining a uniform time gap. Deposition by integrated approach results in the formation of dense arrays of Pt nanostructure as compared to continuous deposition. These high number density integrated arrays with low Pt loading of 0.10 mg cm −2 at the cathode provide enhanced performance compared to non-integrated cathode catalyst prepared by continuous deposition and standard commercial electrodes with Pt loadings of 1 mg cm −2 . The performance is compared on the basis of polarization curve measurements and the calculated power density values. PEM fuel cell with dual integrated cathode showed an improved power density of 0.90 W cm −2 , which is higher than continuously deposited cathode catalyst with maximum power density of 0.67 W cm −2 for the same Pt loading of 0.10 mg cm −2 . - Highlights: • Conical nanostructures with high number density are prepared by a novel integrated deposition technique. • Electrode with such catalyst shows maximum performance of 0.9 W cm −2 . • Integrated catalyst performs better than continuously prepared nanostructure catalyst.

  6. Comparison of The Performance of Proton Exchange Membrane Fuel Cell (PEMFC Electrodes with Different Carbon Powder Content and Methods of Manufacture

    Directory of Open Access Journals (Sweden)

    Dedi Rohendi

    2016-11-01

    Full Text Available Carbon powder in the gas diffusion layer (GDL contained in the membrane electrode assembly (MEA has an important role in the flow of electrons and reactant gas. Meanwhile, the method of making the electrode is one of the many studies conducted to determine the most appropriate method to use. Comparative study of the performance of proton exchange membrane fuel cell (PEMFC electrodes with different carbon powder content (vulcan XC-72 in the GDL and methods of manufacture of the electrode between casting and spraying method has been carried out. The spraying method consists of one layer and three layer of catalyst layer (CL. The content of carbon powder in the GDL as much as 3 mg cm-2 has a better performance compared to 1.5 mg cm-2 with an increase of 177.78% current density at 0.6 V. Meanwhile, the manufacture of CL with three-layer spraying method has better performance compared with one-layer spraying and casting method.

  7. Evaluation of reciprocating electromagnetic air pumping for portable PEMFC

    International Nuclear Information System (INIS)

    Kwon, Kilsung; Kang, Ho; Kang, Seongwon; Kim, Daejoong

    2013-01-01

    In this paper, we present a proton exchange membrane fuel cell (PEMFC) integrated with an electromagnetic (EM) air pump. The EM air pump provides the PEMFC with air by reciprocating motions of the permanent magnet attached to a flexible membrane. We performed a parametric study to decide the optimal dimensions of the reciprocating EM air pump. The effects of various operating parameters on the EM air pump were investigated with the root-mean-square (RMS) flow rate and current. A core with a higher relative permeability shows better performance. The RMS current linearly increases with the applied voltage and shows no dependence on the frequency. The RMS flow rate also increases with the voltage. The RMS flow rate per power consumption is highest at the frequency around 20 Hz and decreases as the applied voltage increases. When the reciprocating EM air pump was used to supply air to the portable PEMFC, it was found that the power density of the PEMFC increases with the applied voltage and shows the highest performance at the frequency of 10 Hz. We compared the performance of the PEMFC between the flow meter and the EM air pump used as an air supplier. About 81% of the output power using the flow meter was obtained when the EM air pump is operated at the applied voltage of 5 V. The parasitic power ratio reaches at its minimum value about 0.1 with an EM applied voltage of 0.25V. (paper)

  8. Effects of cathode channel size and operating conditions on the performance of air-blowing PEMFCs

    International Nuclear Information System (INIS)

    Kim, Bosung; Lee, Yongtaek; Woo, Ahyoung; Kim, Yongchan

    2013-01-01

    Highlights: • Effect of cathode channel size on the air-blowing PEMFC is analyzed. • Performance and EIS tests of air-blowing PEMFCs are conducted. • Test conditions include the operating temperature, fan voltage, and anode humidity. • Flooding is a limiting factor for decreasing channel size at low temperature. • Water management is investigated by analyzing ohmic resistance. - Abstract: Air-blowing proton exchange membrane fuel cells (PEMFCs) have been developed as a potential new power source for portable electronic devices. However, air-blowing PEMFCs show lower performance than compressed-air PEMFCs because of their adverse operating conditions. In this study, the effects of the cathode channel size and operating conditions on the performance of the air-blowing PEMFC were analyzed. At the normal operating temperature, the performance of the air-blowing PEMFC improved with the decrease in the cathode channel size. However, at a low operating temperature and low fan voltage, massive flooding limits the decrease in the cathode channel size. In addition, water management in the air-blowing PEMFC was investigated by analyzing ohmic resistance. The transition current density between the humidification and the flooding region decreased with decreasing cathode channel size and operating temperature

  9. Current density and polarization curves for radial flow field patterns applied to PEMFCs (Proton Exchange Membrane Fuel Cells)

    International Nuclear Information System (INIS)

    Cano-Andrade, S.; Hernandez-Guerrero, A.; Spakovsky, M.R. von; Damian-Ascencio, C.E.; Rubio-Arana, J.C.

    2010-01-01

    A numerical solution of the current density and velocity fields of a 3-D PEM radial configuration fuel cell is presented. The energy, momentum and electrochemical equations are solved using a computational fluid dynamics (CFD) code based on a finite volume scheme. There are three cases of principal interest for this radial model: four channels, eight channels and twelve channels placed in a symmetrical path over the flow field plate. The figures for the current-voltage curves for the three models proposed are presented, and the main factors that affect the behavior of each of the curves are discussed. Velocity contours are presented for the three different models, showing how the fuel cell behavior is affected by the velocity variations in the radial configuration. All these results are presented for the case of high relative humidity. The favorable results obtained for this unconventional geometry seems to indicate that this geometry could replace the conventional commercial geometries currently in use.

  10. Peclet number analysis of cross-flow in porous gas diffusion layer of polymer electrolyte membrane fuel cell (PEMFC).

    Science.gov (United States)

    Suresh, P V; Jayanti, Sreenivas

    2016-10-01

    Adoption of hydrogen economy by means of using hydrogen fuel cells is one possible solution for energy crisis and climate change issues. Polymer electrolyte membrane (PEM) fuel cell, which is an important type of fuel cells, suffers from the problem of water management. Cross-flow is induced in some flow field designs to enhance the water removal. The presence of cross-flow in the serpentine and interdigitated flow fields makes them more effective in proper distribution of the reactants on the reaction layer and evacuation of water from the reaction layer than diffusion-based conventional parallel flow fields. However, too much of cross-flow leads to flow maldistribution in the channels, higher pressure drop, and membrane dehydration. In this study, an attempt has been made to quantify the amount of cross-flow required for effective distribution of reactants and removal of water in the gas diffusion layer. Unit cells containing two adjacent channels with gas diffusion layer (GDL) and catalyst layer at the bottom have been considered for the parallel, interdigitated, and serpentine flow patterns. Computational fluid dynamics-based simulations are carried out to study the reactant transport in under-the-rib area with cross-flow in the GDL. A new criterion based on the Peclet number is presented as a quantitative measure of cross-flow in the GDL. The study shows that a cross-flow Peclet number of the order of 2 is required for effective removal of water from the GDL. Estimates show that this much of cross-flow is not usually produced in the U-bends of Serpentine flow fields, making these areas prone to flooding.

  11. Evaluation and application of PEMFC fuel cell's technologies developed at IPEN applied to a 500 W{sub e} fuel cell stack; Avaliacao e aplicacao de tecnologias de celulas a combustivel tipo PEMFC desenvolvida no IPEN em um modulo de 500 W{sub e} de potencia nominal

    Energy Technology Data Exchange (ETDEWEB)

    Cunha, Edgar Ferrari da

    2009-07-01

    This work is part of a research project on PEMFC technologies carried out in IPEN to develop and optimize a 500 W{sub e} fuel cell stack. The MEAs scaling up from 25 cm{sup 2} to 144 cm{sup 2} produced by the method of sieve printing; computational fluid dynamics by computer simulation of gas flow channels in bipolar plates using COMSOL{sup R} program and the use of Pt/C electrodes developed by alcohol reduction method in single cells were used to build a stack of 500 W{sub e} nominal power for possible commercial applications, produced with national technology and industrial support. A 100 hours fuel cell's test was carried out in a 144 cm{sup 2} single cell to study the stability of the MEA fabricated by sieve printing method. This single cell showed good stability within this period of time. The developed stack has reached the maximum power of 574 W{sub e} at 100 A (694.4 mA cm{sup -2}). The operating power of 500 W{sub e} was obtained at 77.7 A (540.1 mA cm{sup -2}) and potential of 6.43 V, with efficiency of 43.3%. In terms of cogeneration, the thermal power or generated heat by the stack was 652 W{sub t}. The initial estimated cost for the 500 W{sub e} stack was about R$ 4,500.00, considering only the used materials for its construction. (author)

  12. Catalyst FeNi supported on nanometric mezoporous oxide for PEMFC applications

    DEFF Research Database (Denmark)

    Serban, E. C.; Banu, N.; Marinescu, A. C.

    2011-01-01

    Proton exchange membrane fuel cells (PEMFC) are studied intensive for hydrogen - oxygen couple conversion into electrical power via electro-chemical process. Electrocatalyst performances (defined by specific area and catalytic activity) represent a key point for hydrogen oxidation - anode reactio...

  13. Catalyst FeNi supported on nanometric mezoporous oxide for PEMFC applications

    DEFF Research Database (Denmark)

    Serban, E. C.; Banu, N.; Marinescu, A. C.

    2011-01-01

    Proton exchange membrane fuel cells (PEMFC) are studied intensive for hydrogen - oxygen couple conversion into electrical power via electro-chemical process. Electrocatalyst performances (defined by specific area and catalytic activity) represent a key point for hydrogen oxidation - anode reaction...

  14. Integrated PEMFC Flow Field Design Concept for Gravity Independent Passive Water Removal Project

    Data.gov (United States)

    National Aeronautics and Space Administration — ElectroChem proposes a Phase II program to advance its very successful SBIR Phase I PEM fuel cell (PEMFC) program. In Phase I, the unique integrated-flow-field...

  15. PEMFC MEA and System Design Considerations

    Energy Technology Data Exchange (ETDEWEB)

    Knights, Shanna [Ballard Power Systems, Inc.; Bashyam, Rajesh [Ballard Power Systems, Inc.; He, Ping [Ballard Power Systems, Inc.; Lauritzen, Michael [Ballard Power Systems, Inc.; Startek, Cara [Ballard Power Systems, Inc.; Colbow, Vesna [Ballard Power Systems, Inc.; Cheng, Tommy [Ballard Power Systems, Inc.; Kolodziej, Joanna [Ballard Power Systems, Inc.; Wessel, Silvia [Ballard Power Systems, Inc.

    2011-07-01

    Proton exchange membrane fuel cells (PEMFCs) are being developed and sold commercially for multiple near term markets. Ballard Power Systems is focused on the near term markets of backup power, distributed generation, materials handling, and buses. Significant advances have been made in cost and durability of fuel cell products. Improved tolerance to a wide range of system operation and environmental noises will enable increased viability across a broad range of applications. In order to apply the most effective membrane electrode assembly (MEA) design for each market, the system requirements and associated MEA failures must be well understood. The failure modes associated with the electrodes and membrane degradation are discussed with respect to associated system operation and mitigating approaches. A few key system considerations that influence MEA design include expected fuel quality, balance-of-plant materials, time under idle or open circuit operation, and start-up and shut-down conditions.

  16. CO tolerance effects of tungsten-based PEMFC anodes

    International Nuclear Information System (INIS)

    Pereira, Luis Gustavo S.; Santos, Fatima R. dos; Pereira, Maristela E.; Paganin, Valdecir A.; Ticianelli, Edson A.

    2006-01-01

    The performance of proton exchange membrane fuel cells (PEMFC) fed with CO-contaminated hydrogen was investigated for anodes with PtWO x /C and phosphotungstic acid (PTA) impregnated Pt/C electrocatalysts. A quite high performance was achieved for the PEMFC fed with H 2 + 100 ppm CO with anodes containing 0.4 mg PtWO x cm -2 and also for those with 0.4 mg Pt cm -2 impregnated with ca. 1 mg PTA cm -2 . A decay of the single cell performance with time is observed, and this was attributed to an increase of the membrane resistance due to the polymer degradation promoted by the crossover of the tungsten species throughout the membrane

  17. Development of proton exchange membranes fuel cells with sulfonated HTPB-phenol; Desenvolvimento de membranas polimericas trocadoras de protons utilizando PBLH-fenol

    Energy Technology Data Exchange (ETDEWEB)

    Ferraz, Fernando A.; Oliveira, Angelo R.S.; Cesar-Oliveira, Maria Aparecida F. [Universidade Federal do Parana (UFPR), Curitiba, PR (Brazil). Dept. de Quimica. Lab. de Polimeros Sinteticos], e-mail: ferraz@quimica.ufpr.br; Cantao, Mauricio P. [LACTEC - Instituto de Tecnologia para o Desenvolvimento, Curitiba, PR (Brazil). Centro Politecnico

    2007-07-01

    Proton exchange membrane fuel cells (PEMFC) have been paid attention as promising candidates for vehicle and portable applications. PEMFC employ proton exchange polymer membrane which serves as an electrolyte between anode and cathode. Nafion{sup R} (DuPont), perfluorosulfonic acid/PTFE copolymer membranes are typically used as the polymer electrolyte in PEMFC due to their good chemical and mechanical properties as well as high proton conductivity. However, high cost of these materials is one of main obstacles for commercialization of PEMFC. Extensive efforts have been devoted to develop alternative polymer electrolyte membranes. Our group have investigated the development of proton exchange membranes fuel cells using sulfonated HTPB-Phenyl ether (HTPB-Phenol), making possible the formation of membranes with sulfonated groups amount of 2,4, 2,5 and 2,8 mmol/g of dry polymer from HTPB-Phenol 80, 98 and 117 respectively. These results mean a bigger values than those of the Nafion{sup R} membranes, that possess an ion exchange capacity of 0,67 up to 1,25 mmol/g of sulfonated groups. (author)

  18. A PEMFC hybrid electric vehicle real time control system

    Science.gov (United States)

    Sun, Hongqiao

    In recent years, environmental friendly technologies and alternative energy solutions have drawn a lot of public attentions due to global energy crisis and pollution issues. Fuel cell (FC), a technology invented almost at the same time as the internal combustion (IC) engine, is now the focus of the automotive industry again. The fuel cell vehicle (FCV) has zero emission and its efficiency is significantly higher than the conventional IC engine power vehicles. Among a variety of FCV technologies, proton exchange membrane (PEM) FC vehicle appears to be far more attractive and mature. The prototype PEMFC vehicle has been developed and demonstrated to the public by nearly all the major automotive manufacturers in recent years. However, to the interest of the public research, publications and documentations on the PEMFC vehicle technology are rarely available due to its proprietary nature, which essentially makes it a secured technology. This dissertation demonstrates a real world application of a PEMFC hybrid electric vehicle. Through presenting the vehicle design concept, developing the real time control system and generating generic operation principles, this dissertation targets at establishing the public knowledge base on this new technology. A complete PEMFC hybrid electric vehicle design, including vehicle components layout, process flow diagram, real time control system architecture, subsystem structures and control algorithms, is presented in order to help understand the whole vehicle system. The design concept is validated through the vehicle demonstration. Generic operating principles are established along with the validation process, which helps populate this emerging technology. Thereafter, further improvements and future research directions are discussed.

  19. Analysis for impedance electrochemistry 'on-line' of membrane/electrode assemble (MEA) of protons exchange membrane fuel cells (PEMFC); Analise por impedancia eletroquimica 'on-line' de conjuntos eletrodos/membrana (MEA) de celulas a combustivel a membrana polimetrica (PEMFC)

    Energy Technology Data Exchange (ETDEWEB)

    Santos, Antonio Rodolfo dos

    2007-07-01

    This work reports results of studies and characterization on membrane electrode assemblies (MEAs) for proton exchange membrane fuel cell (PEMFC). Some cell operation conditions and different processes of MEA production were investigated. The electrochemical impedance spectroscopy technique (EIS) (in situ - 0 to 16 A) was used 'on-line' as a tool for diagnosis, concerning the cell performance. The EIS measurements were carried out with a FC350 Fuel Cell EIS System (GAMRY), coupled to a PC4 potentiostat/galvanostat and connected to the electronic load (TDI) for 'on-line' EIS experiments (100 mHz - 10 kHz, dU = 5 mV). MEAs with 25 cm{sup 2} surface area, using PtM/C 20% (M Ru, Sn or Ni) electrocatalysts were manufactured using the alcohol reduction process (ARP). The catalytic ink was applied directly into the carbon cloth (GDL) and pressed in the Nafion membrane (105). MEAs using Pt/C and Pt Ru/C 20% from E-TEK electrocatalysts were manufactured by comparison. All the cathodes were sprayed with Pt/C 20% from E-TEK. The noble metal concentrations used were set to 0.4 mg Pt.cm{sup -2} at the anode and 0.6 mg Pt.cm{sup -2} at the cathode (E-TEK). Nyquist diagrams of the MEAs with Pt/C and PtRu/C from E-TEK or PtM/C (M = Ru, Sn or Ni) ARP showed essentially the same ohmic resistances for the MEAs. This fact can be explained by suppression of agglomerates during the MEA preparation process or by the homogeneity of the anchored electrocatalysts at the carbon surface. It could also be observed, at low current densities, that there was a significant performance difference between the electrocatalysts from E-TEK and those prepared with the alcohol reduction process. The polarization curves results confirmed that the Pt M/C (M = Ru, Sn or Ni) ARP showed an activity increase for the methanol and ethanol fed cells. The technique of EIE was shown efficient for the evaluation of the method preparation of MEAs and the acting of the cell, the results of EIE

  20. A mathematical model for PEMFC in different flow modes

    Science.gov (United States)

    Ge, Shan-Hai; Yi, Bao-Lian

    A two-dimensional, steady state model for proton exchange membrane fuel cell (PEMFC) is presented. The model is used to describe the effect of flow mode (coflow and counterflow), operation conditions and membrane thickness on the water transport, ohmic resistance and water distribution in the membrane, current density distribution along the channel and performance of PEMFC. Effect of liquid water on the transport in the two-phase region of cathode diffusion layer was considered. Water transport in the membrane by electro-osmosis drag, diffusion and convection were combined in this model. The model predicts that the dry reactant gases can be well internally humidified and maintain high performance when PEMFC is operated in the counterflow mode without external humidification. Counterflow mode does not show any advantageous while the reactant gases are high humidified or saturated. Compared to the coflow mode, counterflow mode improves the current density distribution with dry or low humidity gases. The higher the anode is humidified, the more water will migrate from anode to cathode. The modeling results compare very well with experimental results.

  1. Swelling behavior of PEMFC during conditioning

    Directory of Open Access Journals (Sweden)

    J. Parrondo

    2007-09-01

    Full Text Available Polymeric cation exchange membranes (PEMFC are used in fuel cell technology. These membranes act as a physical barrier between anode and cathode, but diffusion through the membrane should allow protons to be carried from anode to cathode at a rate sufficient to supply energy requirements. They avoid any direct reaction of oxygen and hydrogen that would diminish fuel cell efficiency. Membranes have to be conditioned before use. This conditioning step changes membrane counterions and modifies their water content, which has an effect on their diffusion coefficients. In order to analyse and quantify the effect of conditioning techniques on membrane performance various experiments with Nafion 117 cation exchange membranes were carried out. Membranes were conditioned using various methods to change the charged cation in the membrane. The reactives used were ultrapure water, nitric acid, hydrochloric acid, hydrogen peroxide, sodium chloride, potassium chloride and ethylene glycol, all at room temperature. Some conditioning methods were carried out using solvents heated to 100 ºC. Water content was indirectly monitored by measuring membrane swelling. Results show that membrane conditioning with strong acids followed by treatment with water increases membrane water content by about 5%. Using high-temperature treatment the water content also increases. Water uptake or release from membranes is analysed in terms of water activity.

  2. Parametric investigation to enhance the performance of a PBI-based high-temperature PEMFC

    International Nuclear Information System (INIS)

    Ferng, Y.M.; Su, A.; Hou, J.

    2014-01-01

    Highlights: • A in-house PBI PEMFC is prepared by the Fuel Cell Center of Yuan Ze University. • Parametric effects to enhance the PBI based PEMFC performance are investigated. • Experiments and simulations are performed to study these parametric effects. • Cell performance is enhanced with the lower PBI loading and higher temperature. • Thinner CL thickness and higher acid doping benefit to the cell performance also. - Abstract: With the advantages of simpler heat and water management, lower CO poisoning, and higher reaction kinetics, the high-temperature polybenzimidazole (PBI)-based proton exchange membrane fuel cell (PEMFC) can be considered as one of the commercialized energy generators in the near future. This paper experimentally and analytically investigates different design and operating parameters to enhance the performance of a PBI-based PEMFC, an in-house cell prepared in the Fuel Cell Center of Yuan Ze University. These parameters studied include PBI loading, operating temperature, gas flowrate, electrode thickness and porosity, and acid doping level. Experiments are performed to study the effects of PBI loading, operating temperature, and gas flowrate on the cell performance. Validated against the measured data of polarization and power curves, a simplified two-dimensional model for this PBI-based PEMFC is also developed to help the experiments to investigate other parameters. Based on the experimental data and the model predictions, the cell performance can be enhanced as the PBI loading is reduced, the operating temperature is elevated. Thinner electrode thickness, smaller porosity, and higher acid doping level are also predicted to benefit to the performance of the PBI-based PEMFC

  3. Graphitised Carbon Nanofibres as Catalyst Support for PEMFC

    DEFF Research Database (Denmark)

    Yli-Rantala, E.; Pasanen, A.; Kauranen, P.

    2011-01-01

    Graphitised carbon nanofibres (G-CNFs) show superior thermal stability and corrosion resistance in PEM fuel cell environment over traditional carbon black (CB) and carbon nanotube catalyst supports. However, G-CNFs have an inert surface with only very limited amount of surface defects...... (PANI) precursor. The modified surfaces were studied by FTIR and XPS and the electrochemical characterization, including long-term Pt stability tests, was performed using a low-temperature PEMFC single cell. The performance and stability of the G-CNF supported catalysts were compared with a CB supported...

  4. Waste Heat Recovery of a PEMFC System by Using Organic Rankine Cycle

    Directory of Open Access Journals (Sweden)

    Tianqi He

    2016-04-01

    Full Text Available In this study, two systems are brought forward to recover the waste heat of a proton exchange membrane fuel cell (PEMFC, which are named the organic Rankine cycle (ORC, and heat pump (HP combined organic Rankine cycle (HPORC. The performances of both systems are simulated on the platform of MATLAB with R123, R245fa, R134a, water, and ethanol being selected as the working fluid, respectively. The results show that, for PEMFC where operating temperature is constantly kept at 60 °C, there exists an optimum working temperature for each fluid in ORC and HPORC. In ORC, the maximal net power can be achieved with R245fa being selected as the working fluid. The corresponding thermal efficiency of the recovery system is 4.03%. In HPORC, the maximal net power can be achieved with water being selected in HP and R123 in ORC. The thermal efficiency of the recovery system increases to 4.73%. Moreover, the possibility of using ORC as the cooling system of PEMFC is also studied. The heat released from PEMFC stack is assumed to be wholly recovered by the ORC or HPORC system. The results indicate that the HPORC system is much more feasible for the cooling system of a PEMFC stack, since the heat recovery ability can be promoted due to the presence of HP.

  5. Optimization of electrical conduction and passivity properties of stainless steels used for PEM fuel cell bipolar plates; Opmisation des proprietes de conduction electrique et de passivite d'aciers inoxydables pour la realisation de plaques bipolaires de pile a combustible de type PEMFC

    Energy Technology Data Exchange (ETDEWEB)

    Andre, J

    2007-10-15

    Among the new technologies for energy for sustainable development, PEMFC (proton exchange membrane fuel cells) offer seducing aspects. However, in order to make this technology fit large scale application requirements, it has to comply with stringent cost, performance, and durability criteria. In such a frame, the goal of this work was to optimize electrical conduction properties and passivity of stainless steels for the conception of PEMFC bipolar plates, used instead of graphite, the reference material. This work presents the possible ways of performance loss when using stainless steels and some methods to solve this problem. Passive film properties were studied, as well as their modifications by low cost industrial surface treatments, without deposition. Ex situ characterizations of corrosion resistance and electrical conduction were performed. Electrochemical impedance spectroscopy, water analysis, surface analysis by microscopy and photoelectron spectroscopy allowed to study the impact of ageing on two alloys in different states, and several conditions representative of an exposure to PEMFC media. Correlations between semi-conductivity properties, composition, and structure of passive layers were considered, but not leading to clear identification of all parameters responsible for electrical conduction and passivity. The plate industrial state is not convenient for direct use in fuel cell to comply with durability and performance requirements. A surface modification studied improves widely electrical conduction at initial state. The performance is degraded with ageing, but maintaining a level higher than the initial industrial state. This treatment increases also corrosion resistance, particularly on the anode side. (author)

  6. Synthesis and characterisation of binary electrocatalysts for electrochemical oxidation of ethanol in PEMFC

    CSIR Research Space (South Africa)

    Masombuka, T

    2008-06-01

    Full Text Available Ethanol is an alternative choice fuel for polymer electrolyte membrane fuel cells (PEMFC), due to its nontoxicity and its availability from biomass resources advocates its use in direct ethanol fuel cells. In this study PtSn/C and Pt...

  7. Modeling and simulation of a residential micro-CHP system based on HT-PEMFC technology

    DEFF Research Database (Denmark)

    Arsalis, Alexandros; Nielsen, Mads Pagh; Kær, Søren Knudsen

    2009-01-01

    Combined-heat-and-power (CHP) technology is a well known and proved method to produce simultaneously power and heat at high efficiencies. This can be further improved by the introduction of a novel micro-CHP residential system based on High Temperature-Proton Exchange Membrane Fuel Cell (HT-PEMFC......). The HT-PEMFC (based on PBI-membrane technology) operates at temperatures near 200oC, and this can be an ideal match for cogeneration residential systems. The proposed system provides electric power, hot water, and space heating for a typical household (1-5 kWe, 5-10 kWth). The micro-CHP system...

  8. Phosphoric acid doped AB-PBI membranes and its applications in high temperature PEMFC

    DEFF Research Database (Denmark)

    He, Ronghuan; Qingfeng, Li; Bjerrum, Niels

    2005-01-01

    in a wide temperature range.. The conductivity of the acid doped ab-PBI membranes was studied in a temperature range of 80oC to 200oC under different relative humidity and with different acid doping levels. PEMFC test results indicated that the fuel cell could be operated at temperatures up to 200o...

  9. The CO poisoning effect in PEMFCs operational at temperatures up to 200 degrees C

    DEFF Research Database (Denmark)

    Li, Qingfeng; He, Ronghuan; Gao, Ji-An

    2003-01-01

    The CO poisoning effect on carbon-supported platinum catalysts (at a loading of 0.5 mg Pt/cm(2) per electrode! in polymer electrolyte membrane fuel cells (PEMFCs) has been investigated in a temperature range from 125 to 200 degreesC with the phosphoric acid-doped polybenzimidazole membranes...

  10. Benzene electro-oxidation in a PEMFC for phenol and electricity cogeneration

    Energy Technology Data Exchange (ETDEWEB)

    Cai, Rui; Ji, Baofeng; Yang, Weishen; Xin, Qin [State Key Laboratory of Catalysis, Dalian Institute of Chemical Physics, CAS, P.O. Box 110, 116023 Dalian (China); Song, Shuqin; Douvartzides, Savvas; Tsiakaras, Panagiotis [Department of Mechanical Engineering, School of Engineering, University of Thessalia, Pedion Areos, 383 34 Volos (Greece); Sun, Gongquan [Direct Alcohol Fuel Cell Lab, Dalian Institute of Chemical Physics, CAS, P.O. Box 110, 116023 Dalian (China)

    2005-11-09

    In the present investigation, the electrochemically-assisted oxidation of benzene in a H{sub 2}-O{sub 2} proton exchange membrane fuel cell (PEMFC), for electricity and phenol cogeneration is studied. Experiments were carried out in a PEMFC electrochemical reactor using Pd black as cathode electrocatalyst at 60 and 80{sup o}C, respectively and 1atm back pressure. Indeed, it was found that the only product detected under the examined experimental conditions was phenol. The online GC product analysis revealed that it is impossible to produce phenol when the fuel cell circuit is open (I=0) under all the examined experimental conditions. When the fuel cell circuit was closed, however, the phenol yield was found to follow a volcano-type dependence on the current of the external circuit. It was found that the maximum phenol yield was 0.35% at 100mA/cm{sup 2} at 80{sup o}C. At the same time, the PEMFC performance was also investigated during the phenol generation process. Furthermore, experiments with the rotating ring disc electrode (RRDE) technique showed that the intermediate oxidation product, i.e. H{sub 2}O{sub 2} existed during the oxygen electro-reduction process. The cyclic voltammograms showed that benzene was strongly adsorbed on the Pd surface, leading to a degradation of the PEMFC performance.

  11. Nanostructured TiO2 Doped with Nb as a Novel Support for PEMFC

    Directory of Open Access Journals (Sweden)

    Edgar Valenzuela

    2013-01-01

    Full Text Available Nowadays, one of the major issues of the PEMFC concerns the durability. Historically, carbon has been used as a catalyst support in PEMFC; nevertheless, under the environmental conditions of the cell, the carbon is oxidized, leaving the catalyst unsupported. In order to increase the stability and durability of the catalyst in the PEMFC, a novel nanostructured metallic oxide support is proposed. In this work, TiO2 was doped with Nb to obtain a material that combines chemical stability, high surface area, and an adequate electronic conductivity in order to be a successful catalyst support candidate for long-term PEMFC applications. The TiO2-Nb nanostructured catalyst support was physically and electrochemically characterized. According to the results, the TiO2-Nb offers high surface area and good particle dispersion; also, the electrochemical activity and stability of the support were evaluated under high potential conditions, where the TiO2-Nb proved to be much more stable than carbon.

  12. Carbon film-coated 304 stainless steel as PEMFC bipolar plate

    Science.gov (United States)

    Chung, Chih-Yeh; Chen, Shi-Kun; Chiu, Po-Jen; Chang, Ming-Hsin; Hung, Tien-Tsai; Ko, Tse-Hao

    Carbon film-coated stainless steel (CFCSS) has been evaluated as a low-cost and small-volume substitute for graphite bipolar plate in polymer electrolyte membrane fuel cell (PEMFC). In the present work, AISI 304 stainless steel (304SS) plate was coated with nickel layer to catalyze carbon deposits at 680°C under C 2H 2/H 2 mixed gas atmosphere. Surface morphologies of carbon deposits exhibited strong dependence on the concentration of carbonaceous gas and a continuous carbon film with compact structure was obtained at 680 °C under C 2H 2/H 2 mixed gas ratio of 0.45. Systematic analyses indicated that the carbon film was composed of a highly ordered graphite layer and a surface layer with disarranged graphite structure. Both corrosion endurance tests and PEMFC operations showed that the carbon film revealed excellent chemical stability similar to high-purity graphite plate, which successfully protected 304SS substrate against the corrosive environment in PEMFC. We therefore predict CFCSS plates may practically replace commercial graphite plates in the application of PEMFC.

  13. Electric toy vehicle powered by a PEMFC stack

    Energy Technology Data Exchange (ETDEWEB)

    Beneito, Ruben; Vilaplana, Joaquin; Gisbert, Santiago [Technological Institute for Toy (AIJU), 03440 Ibi (Spain)

    2007-07-15

    The article describes the design and development of an electric toy vehicle powered by a fuel cell stack. The system consisted of a 150 W PEMFC stack powered by hydrogen/air, a tank of metal hydrides of AB (TiFe) alloy type with a capacity of 300 standard litres, for storing hydrogen, and an electronic power device based on electrolytic capacitors, to supply peak power demands during acceleration and start up of the vehicle. The air supply was provided by a fan preceded by a filter, and in a similar manner the stack was cooled by an air ventilation system. An electrovalve was used to supply H{sub 2} in dead-ended mode. All the components were integrated in the vehicle, and the prototype was tested in real working conditions, in a test bench and by children. (author)

  14. Optimization of a PEMFC/battery pack power system for a bus application

    International Nuclear Information System (INIS)

    Barelli, Linda; Bidini, Gianni; Ottaviano, Andrea

    2012-01-01

    Highlights: ► A dynamic model of a PEMFC/battery system for bus traction has been developed. ► The model incorporates the dynamics of the fuel cell and the state of charge (SOC) of the battery pack. ► The system output power have been determined according to the real driving load demand of a bus during 12 h. ► The model has allowed the sizing of the fuel cell and the hydrogen tank with the SOC control strategy optimization. ► The PEMFC power that allows to optimize the operation in terms of both SOC control strategy and consumption is 33 kW e . -- Abstract: In a global environment context in which the urgent need to reduce pollutant emissions is of central relevance, it is becoming increasingly important the research for solutions, concerning the vehicular transport sector with low environmental impact. Fuel cell technology is expected to become a viable solution for these applications due to its environmental friendly characteristics. The present study concerns the traction system of a bus considering the case of hybrid solutions consisting of a proton exchange membrane fuel cell (PEMFC) in parallel with a battery pack. In particular, a dynamic model of a PEMFC/battery system is presented for the application under study. The model incorporates the dynamics of the fuel cell and the state of charge (SOC) of the battery pack. The fuel cell and the battery output power have been determined according to the real driving load demand of a bus taking into consideration a daily operation of 12 h. Such a model has allowed the correct dimensioning of the hybrid power system (giving a particular attention to the fuel cell and the hydrogen tank) together with the optimization of the SOC control strategy.

  15. Systematic studies of the gas humidification effects on spatial PEMFC performance distributions

    International Nuclear Information System (INIS)

    Reshetenko, Tatyana V.; Bender, Guido; Bethune, Keith; Rocheleau, Richard

    2012-01-01

    Highlights: ► We investigated impacts of gases humidification on a local PEMFC performance. ► The spatial performance and EIS were studied by a segmented cell system. ► The data were analyzed in the terms of voltage losses. ► A reduction in anode/cathode gases humidification decreased a PEMFC performance. ► A decrease of humidification led to non-uniform performances and voltage losses distributions. - Abstract: The overall current density that is measured in a proton exchange membrane fuel cell (PEMFC) represents the average of the local reaction rates. The overall and local PEMFC performances are determined by several primary loss mechanisms, namely activation, ohmic, and mass transfer. Spatial performance and loss variabilities are significant and depend on the cell design and operating conditions. A segmented cell system was used to quantify different loss distributions along the gas channel to understand the effects of gas humidification. A reduction in the reactant stream humidification decreased cell performance and resulted in non-uniform distributions of overpotentials and performance along the flow field. Activation and ohmic overpotentials increased with a relative humidity decrease due to insufficient membrane and catalyst layer hydration. The relative humidity of the cathode had a strong impact on the mass transfer overpotential due to a lower oxygen permeability through the dry Nafion film covering the catalyst surface. The mass transfer loss distribution was non-uniform, and the mass transfer overpotential increased for the outlet segments due to the oxygen consumption at the inlet segments, which reduced the oxygen concentration downstream, and a progressive water accumulation from upstream segments. Electrochemical impedance spectroscopy (EIS) and an equivalent electric circuit (EEC) facilitated the analysis and interpretation of the segmented cell data.

  16. Synthesis of protons exchange polymeric membranes via co-poly-esters doped with sodium dodecyl sulfate for application in PEM fuel cells; Sintese de membranas polimericas condutoras de protons por imobilizacao de MDs em copoliesteres para aplicacao em PEM-FC

    Energy Technology Data Exchange (ETDEWEB)

    Fiuza, R.A.; Brioude, M.M.; Bresciani, D.; Jose, N.M.; Boaventura, J.S. [Universidade Federal da Bahia (IQ/UFBA), Salvador, BA (Brazil). Inst. de Quimica

    2008-07-01

    Polymers are largely studied for use in PEM-type fuel cell (Proton Exchange membrane, PEMFC). These fuel cells are based on polymer membranes as electrolyte, also called protons conductor. This work developed co-polyesters made electrical conductors by doping with sodium dodecyl sulfate. The copolymers were synthesized from the copolymerization of terephthalic and adipic acids with glycerol. The material was processed in a reactor and shaped by hot pressing, yielding homogeneous and flexible plates, with excellent surface finish. The co-polyesters were analyzed by SEM, FTIR, TG, DSC, and XRD. The thermal analysis showed that the composites were thermally stable up to about 250 deg C. The micrographics revealed the MDS homogeneously dispersed in the polymeric matrix. These copolymers showed electrical conductivity between 10-7 to 10-1 S/cm, suggesting strong potential use in PEM fuel cells. (author)

  17. Tin Dioxide Coated Carbon Materials for Extended Lifetime of Cathodic Electrocatalysts for PEMFC

    OpenAIRE

    Labbé, Fabien; Ahmad, Yasser; Molina Concha, Belen; Guerin, Katia; Chatenet, Marian; Metkemeijer, Rudolf; Berthon-Fabry, Sandrine

    2017-01-01

    International audience; Proton Exchange Membrane Fuel Cells (PEMFC) are energy converters which can be used for automotive, stationary or nomad applications. This system is already used in niche markets. Nevertheless, some drawbacks, such as insufficient durability, need to be overcome to increase the market deployment. This insufficient durability is strongly linked to the corrosion of the carbon support in the cathode electrocatalyst. The carbon corrosion leads to a local collapse of the su...

  18. Fluorination: a new way to enhance the durability of carbon supports for PEMFC application

    OpenAIRE

    Berthon-Fabry, Sandrine; Labbé, Fabien; Metkemeijer, Rudolf; Ahmad, Yasser; Batisse, Nicolas; Dubois, Marc; Guérin, Katia; Molina Concha, Belen; Maillard, Frédéric; Dubau, Laetitia; Chattot, Raphaël; Chatenet, Marian

    2016-01-01

    International audience; Proton exchange membrane fuel cells (PEMFC) are energy converters that can power nomad, automotive or stationary systems without emission of pollutants. This technology is already used for niche markets, but some challenges must be overcome to enable large-scale deployment. In particular, the electrochemical corrosion of the carbon support at the cathode remains a major concern especially under start-stop conditions. This corrosion causes massive detachment of the supp...

  19. Durable electrocatalytic-activity of Pt-Au/C cathode in PEMFCs.

    Science.gov (United States)

    Selvaganesh, S Vinod; Selvarani, G; Sridhar, P; Pitchumani, S; Shukla, A K

    2011-07-21

    Longevity remains as one of the central issues in the successful commercialization of polymer electrolyte membrane fuel cells (PEMFCs) and primarily hinges on the durability of the cathode. Incorporation of gold (Au) to platinum (Pt) is known to ameliorate both the electrocatalytic activity and stability of cathode in relation to pristine Pt-cathodes that are currently being used in PEMFCs. In this study, an accelerated stress test (AST) is conducted to simulate prolonged fuel-cell operating conditions by potential cycling the carbon-supported Pt-Au (Pt-Au/C) cathode. The loss in performance of PEMFC with Pt-Au/C cathode is found to be ∼10% after 7000 accelerated potential-cycles as against ∼60% for Pt/C cathode under similar conditions. These data are in conformity with the electrochemical surface-area values. PEMFC with Pt-Au/C cathode can withstand >10,000 potential cycles with very little effect on its performance. X-ray diffraction and transmission electron microscopy studies on the catalyst before and after AST suggest that incorporating Au with Pt helps mitigate aggregation of Pt particles during prolonged fuel-cell operations while X-ray photoelectron spectroscopy reflects that the metallic nature of Pt is retained in the Pt-Au catalyst during AST in comparison to Pt/C that shows a major portion of Pt to be present as oxidic platinum. Field-emission scanning electron microscopy conducted on the membrane electrode assembly before and after AST suggests that incorporating Au with Pt helps mitigating deformations in the catalyst layer. This journal is © the Owner Societies 2011

  20. Modeling and optimization of a 1 kWe HT-PEMFC-based micro-CHP residential system

    DEFF Research Database (Denmark)

    Arsalis, Alexandros; Nielsen, Mads Pagh; Kær, Søren Knudsen

    2012-01-01

    A high temperature-proton exchange membrane (HT-PEMFC)-based micro-combined-heat-and-power (CHP) residential system is designed and optimized, using a genetic algorithm (GA) optimization strategy. The proposed system consists of a fuel cell stack, steam methane reformer (SMR) reactor, water gas s...

  1. Study on Air-cooled Self-humidifying PEMFC Control Method Based on Segmented Predict Negative Feedback Control

    International Nuclear Information System (INIS)

    Zhiyu, You; Tao, Xu; Zhixiang, Liu; Yun, Peng; Weirong, Cheng

    2014-01-01

    In order to obtain the optimal output performance of the air-cooled self-humidifying proton exchange membrane fuel cell (PEMFC), the operating temperature, the air flow, purge interval and some other parameters must be controlled strictly. As a key factor, the operating temperature mainly determines the optimal output performance of the fuel cell. However, some intrinsic issues such as long adjusting time, over-shoot still exist inevitably for the traditional PID temperature-controlled method in circumstances of the load variation. Consequently, output performance of PEMFC decreases because the operating temperature of the fuel cell fails to reach, and the corresponding lifetime of PEMFC is also reduced. In this study, a segmented predict negative feedback control method, based on the advance proportional control one, is proposed and verified by experiments to overcome the shortcomings of PID temperature control. The results demonstrate that the optimal output performance of PEMFC can be realized by utilizing the proposed method for temperature control due to its excellent properties, simple controlling and small over-shoot

  2. A Neural Non-linear Predictive Control for PEM-FC

    OpenAIRE

    M. Cirrincione; M. Pucci; G. Cirrincione; M. G. Simões

    2005-01-01

    This paper deals with the application of non-linear predictive control with neural networks to Proton Exchange Membrane Fuel Cells (PEM-FC). The control objective is to regulate the cell voltage, acting on the hydrogen pressure, trying to reduce the variation of the input control variable. An analysis of the non-linearities of the fuel cell stack has been carried out, making use of a suitable fuel cell model. The non-linear predictive control has been implemented by several neural networks (m...

  3. Evaluation of the Scaffolding Effect of Pt Nanowires Supported on Reduced Graphene Oxide in PEMFC Electrodes

    Directory of Open Access Journals (Sweden)

    Peter Mardle

    2018-01-01

    Full Text Available The stacking and overlapping effect of two-dimensional (2D graphene nanosheets in the catalyst coating layer is a big challenge for their practical application in proton exchange membrane fuel cells (PEMFCs. These effects hinder the effective transfer of reactant gases to reach the active catalytic sites on catalysts supported on the graphene surface and the removal of the produced water, finally leading to large mass transfer resistances in practical electrodes and poor power performance. In this work, we evaluate the catalytic power performance of aligned Pt nanowires grown on reduced graphene oxide (rGO (PtNW/rGO as cathodes in 16-cm2 single PEMFCs. The results are compared to Pt nanoparticles deposited on rGO (Pt/rGO and commercial Pt/C nanoparticle catalysts. It is found that the scaffolding effect from the aligned Pt nanowire structure reduces the mass transfer resistance in rGO-based catalyst electrodes, and a nearly double power performance is achieved as compared with the Pt/rGO electrodes. However, although a higher mass activity was observed for PtNW/rGO in membrane electrode assembly (MEA measurement, the power performance obtained at a large current density region is still lower than the Pt/C in PEMFCs because of the stacking effect of rGO.

  4. Control of the Air Supply Subsystem in a PEMFC with Balance of Plant Simulation

    Directory of Open Access Journals (Sweden)

    Alan Cruz Rojas

    2017-01-01

    Full Text Available This paper deals with the design of a control scheme for improving the air supply subsystem of a Proton Exchange Membrane Fuel Cell (PEMFC with maximum power of 65 kW. The control scheme is evaluated in a plant simulator which incorporates the balance of plant (BOP components and is built in the aspenONE® platform. The aspenONE® libraries and tools allows introducing the compressor map and sizing the heat exchangers used to conduct the reactants temperature to the operating value. The PEMFC model and an adaptive controller were programmed to create customized libraries used in the simulator. The structure of the plant control is as follows: the stoichiometric oxygen excess ratio is regulated by manipulating the compressor power, the equilibrium of the anode-cathode pressures is achieved by tracking the anode pressure with hydrogen flow manipulation; the oxygen and hydrogen temperatures are regulated in the heat exchangers, and the gas humidity control is obtained with a simplified model of the humidifier. The control scheme performance is evaluated for load changes, perturbations and parametric variations, introducing a growing current profile covering a large span of power, and a current profile derived from a standard driving speed cycle. The impact of the control scheme is advantageous, since the control objectives are accomplished and the PEMFC tolerates reasonably membrane damage that can produce active surface reduction. The simulation analysis aids to identify the safe Voltage-Current region, where the compressor works with mechanical stability.

  5. Investigation of the internal behavior in segmented PEMFCs of different flow fields during cold start process

    International Nuclear Information System (INIS)

    Lin, R.; Ren, Y.S.; Lin, X.W.; Jiang, Z.H.; Yang, Z.; Chang, Y.T.

    2017-01-01

    In this study, we have researched the internal behavior in segmented proton exchange membrane fuel cells (PEMFCs) with three different flow fields during cold start process. The change of internal current density and temperature in fuel cells with different flow fields could be obviously shown by the printed circuit board (PCB) technology, and the study shows that the flow field is significant for enhancing the cold start ability and durability. Single serpentine flow field has the best cold start performance, while triple channel serpentine flow field has the best uniformity. It is found that without a robust temperature rising tendency, the cell temperature reaching 0 °C does not definitely mean a successful cold start because the cell temperature might drop down 0 °C again. Polarization curves show that there is almost no performance degradation after successful cold start, but the cell degrades quickly after the failed cold start at −7 °C and −10 °C. Based on these characteristics, we optimized the rapid cold start strategy by using electric heating and make it possible to start up the PEMFC at temperatures down to −20 °C within about 11 min. - Highlights: • Segmented fuel cell were used to record the internal current density and temperature distributions during the cold start. • The effects of flow fields on the PEMFC cold start capacity were evaluated. • The effect of cold start on the performance of fuel cell was evaluated. • An optimized strategy was adopted to improve the cold start capacity.

  6. Membranes optimization of the basis of S-peek with different degrees of sulfonation for PEMFC; Otimizacao de membranas a base de S-peek com diferentes graus de sulfonacao para PEMFC

    Energy Technology Data Exchange (ETDEWEB)

    Barreto, E.B.; Fiuza, R.A.; Jose, N.M.; Boaventura, J.S.; Carvalho, L.F.V. [Universidade Federal da Bahia (IQ/UFBA), Salvador, BA (Brazil). Inst. de Quimica. Grupo de Energia e Ciencia dos Materiais

    2008-07-01

    With the growing concern emission of polluting gases in the atmosphere and search for alternative sources of clean energy that can meet the future shortage of oil, the fuel cells have become the target of scientific research in everyone. Among the various types of fuel cells includes the PEMFC (Polymer exchange membrane fuel cell), in the case of a device with high efficiency, without emission of pollutants. This work was to produce membranes and optimizing the basis of S-PEEK (poly-ether-ether-sulfonate) with varying degrees of sulfonation to be applied as electrolytes in fuel cells to the type PEMFC. The membranes were characterized chemically, by thermal analysis, and electrochemistry. (author)

  7. Integrated automation system for a pilot plant for energy conversion using PEMFCs

    International Nuclear Information System (INIS)

    Culcer, Mihai; Iliescu, Mariana; Raceanu, Mircea; Stanciu, Vasile; Stefanescu, Ioan; Enache, Adrian; Lazaro, Pavel Gabriel; Lazaroiu, Gheorghe; Badea, Adrian

    2007-01-01

    Based on Hydrogen and Fuel Cells researches and technological capabilities achieved in the National R and D Programs, ICIT Rm. Valcea built an experimental-demonstrative pilot plant for energy conversion using hydrogen PEMFCs. This pilot plant consists of a fuel processor based on steam methane reforming (SMR) process, a hydrogen purification unit, a PEM fuel cells stack (FCS) and a power electronics unit. The paper deals with the dedicated controlling system that provides automated data acquisition, manual or on-line operational control, gas management, humidification, temperature and flow controls. (authors)

  8. Comparative analysis of 2D and 3D model of a PEMFC in COMSOL

    Science.gov (United States)

    Lakshmi, R. Bakiya; Harikrishnan, N. P.; Juliet, A. Vimala

    2017-10-01

    In this article, 2D and 3D model of a PEMFC has been simulated in order to study their performance when subjected to similar operating conditions. The comparison reveals interesting phenomena of performance enhancement of the fuel cell. Design of fuel cell channel and stationary studies were done in COMSOL. Variations in current density and electrolyte potential from simulation results were observed when operated at a temperature of 120 °C. The electrolyte potential was found to have increased from 1 to 2.5 V and the surface pressure due to fluid flow was found to have increased from 3 to 9.58 Pa.

  9. Electrochemical behaviour of PES ionomer and Pt-free catalyst for PEMFCs

    Directory of Open Access Journals (Sweden)

    STEFANIA GIORDANO

    2013-06-01

    Full Text Available Proton Exchange Membrane Fuel Cells (PEMFCs represent promising technologies to the world economy, with many applications and low environmental impact. A most important aspect concerning their widespread implementation is the cost of polymeric membranes, typically perfluorinated membranes and platinum-based catalytic electrode materials, all of which are necessary to promote electrode reactions, thus increasing fuel cell energy efficiency. In this work, we present some data about non-fluorinated polyetheresulphone (PES membranes and Pt-free catalysts, as possible substitutes of the above materials. Their electrochemical behaviour in oxygen reduction reaction in acidic media are investigated and compared with available reference materials.

  10. Modeling and parametric study of a 1 kWe HT-PEMFC-based residential micro-CHP system

    DEFF Research Database (Denmark)

    Arsalis, Alexandros; Nielsen, Mads Pagh; Kær, Søren Knudsen

    2011-01-01

    A detailed thermodynamic, kinetic and geometric model of a micro-CHP (Combined-Heatand-Power) residential system based on High Temperature-Proton Exchange Membrane Fuel Cell (HT-PEMFC) technology is developed, implemented and validated. HT-PEMFC technology is investigated as a possible candidate...... for fuel cell-based residential micro-CHP systems, since it can operate at higher temperature than Nafion-based fuel cells, and therefore can reach higher cogeneration efficiencies. The proposed system can provide electric power, hot water, and space heating for a typical Danish single-family household....... A complete fuel processing subsystem, with all necessary balance-of-plant components, is modeled and coupled to the fuel cell stack subsystem. The micro-CHP system’s synthesis/ design and operational pattern is analyzed by means of a parametric study. The parametric study is conducted to determine the most...

  11. Magnetic resonance imaging of water distribution and production in a 6 cm{sup 2} PEMFC under operation

    Energy Technology Data Exchange (ETDEWEB)

    Bedet, J. [Methodologie RMN, SRSMC, Nancy-Universite, CNRS, Faculte des Sciences, Boulevard des Aiguillettes, BP 239, 54506 Vandoeuvre-les-Nancy Cedex (France); LEMTA, Nancy-Universite, CNRS, 2 Avenue de la Foret de Haye, BP160, 54504 Vandoeuvre-les-Nancy Cedex (France); Maranzana, G.; Leclerc, S.; Lottin, O.; Moyne, C.; Stemmelen, D. [Methodologie RMN, SRSMC, Nancy-Universite, CNRS, Faculte des Sciences, Boulevard des Aiguillettes, BP 239, 54506 Vandoeuvre-les-Nancy Cedex (France); Mutzenhardt, P.; Canet, D. [LEMTA, Nancy-Universite, CNRS, 2 Avenue de la Foret de Haye, BP160, 54504 Vandoeuvre-les-Nancy Cedex (France)

    2008-06-15

    Polymer electrolyte membrane fuel cell (PEMFC) use perfluorosulfonic acid membranes (for example Nafion {sup registered}) as a solid electrolyte and their performances are strongly dependent on membrane hydration. Therefore, the accurate knowledge of water distribution in the membrane and of the zone of water condensation in the fuel cell is a fundamental issue. Nuclear Magnetic Resonance is a non-destructive and non-invasive technique. It is particularly suited for observing the transport properties of water in a membrane. Magnetic Resonance Imaging (MRI) experiments of a whole fuel cell are more difficult to achieve because they require a PEMFC free of ferromagnetic species and with a minimum of paramagnetic materials. Moreover, difficulties arise because of the electric conductance of most of the fuel cell components (bipolar plates, backing layers, electrodes). These issues have been addressed and MRI experiments of a rectangular 6cm{sup 2} PEMFC under operation have been performed. This fuel cell proved to have performances comparable to commercially available fuel cells. Preliminary results exhibit a progressive accumulation of water close to the gas outlet while the gas inlet remains dry. (author)

  12. Temperature distribution on the MEA surface of a PEMFC with serpentine channel flow bed

    Science.gov (United States)

    Wang, Maohai; Guo, Hang; Ma, Chongfang

    Knowledge of the temperature distribution on the membrane electrode assembly (MEA) surface and heat transfer processes inside a proton exchange membrane fuel cell (PEMFC) is helpful to improvement of cell reliability, durability and performance. The temperature fields on the surface of MEA fixed inside a proton exchange membrane fuel cell with a serpentine channel flow bed were measured by infrared imaging technology under non-humidification conditions. The temperature distributions over the MEA surface under whole channel region were achieved. The experimental results show that the downstream temperatures are higher than the upstream. The hot region on the MEA surface is easy to locate from the infrared temperature image. The mean temperature on the MEA surface and the cell temperature both increase with the current density. Higher current density makes the non-uniformity of temperature distribution on the MEA surface worse. The loading time significantly affects the temperature distribution. Compared with the electrical performance of the cell, the MEA's temperatures need much more time to reach stable. The results indicate that isothermal assumption is not appropriate for a modeling of PEMFCs, and monitoring the temperature of external surface of the flow field plate or end plate cannot supply accurate reference to control the temperatures on MEA surface.

  13. Emission Measurements of Ultracell XX25 Reformed Methanol Fuel Cell System

    Science.gov (United States)

    2008-06-01

    combination of electrochemical devices such as fuel cell and battery. Polymer electrolyte membrane fuel cells ( PEMFC ) using hydrogen or liquid...communications and computers, sensors and night vision capabilities. High temperature PEMFC offers some advantages such as enhanced electrode kinetics and better...tolerance of carbon monoxide that will poison the conventional PEMFC . Ultracell Corporation, Livermore, California has developed a first

  14. Hollow microspheres with a tungsten carbide kernel for PEMFC application.

    Science.gov (United States)

    d'Arbigny, Julien Bernard; Taillades, Gilles; Marrony, Mathieu; Jones, Deborah J; Rozière, Jacques

    2011-07-28

    Tungsten carbide microspheres comprising an outer shell and a compact kernel prepared by a simple hydrothermal method exhibit very high surface area promoting a high dispersion of platinum nanoparticles, and an exceptionally high electrochemically active surface area (EAS) stability compared to the usual Pt/C electrocatalysts used for PEMFC application.

  15. A review on water fault diagnosis of PEMFC associated with the pressure drop

    International Nuclear Information System (INIS)

    Pei, Pucheng; Li, Yuehua; Xu, Huachi; Wu, Ziyao

    2016-01-01

    Highlights: • Reviewed the effect factors and estimations of pressure drop associated with water fault diagnosis. • Reviewed pressure drop-based water fault diagnosis using different indicators. • Deviation of pressure drop is used frequently to diagnose water fault. • Reviewed recovery strategies based on pressure drop used in commercial PEMFC. • Merits, demerits and application prospects of pressure drop-based water fault diagnosis are discussed. - Abstract: The pressure difference between the inlet and outlet of the reactant in fuel cells is called the pressure drop, which is related to the water amount inside the fuel cells. In recent years there have been many studies that used the pressure drop to detect the water content and diagnose water fault of proton exchange membrane fuel cells (PEMFCs). To our knowledge, there has not been a systematic review of these studies. In this paper, the effect variables of pressure drop are reviewed firstly. Then estimations of the theoretical pressure drop are reviewed mainly based on the following four aspects: Bernoulli’s equation, two-phase flow multiplier, Darcy’s law and artificial intelligence. Afterward, the water fault diagnosis based on the pressure drop using the following six indicators are reviewed: indicator of direct pressure drop, its deviation, frequency, multiplier, the ratio of pressure drop to flow rate and the flooding degree. In addition, the strategies of water fault recovery are also summarized. Finally the merits, demerits and application prospects of pressure drop-based water fault diagnosis are presented.

  16. Coordinating IMC-PID and adaptive SMC controllers for a PEMFC.

    Science.gov (United States)

    Wang, Guo-Liang; Wang, Yong; Shi, Jun-Hai; Shao, Hui-He

    2010-01-01

    For a Proton Exchange Membrane Fuel Cell (PEMFC) power plant with a methanol reformer, the process parameters and power output are considered simultaneously to avoid violation of the constraints and to keep the fuel cell power plant safe and effective. In this paper, a novel coordinating scheme is proposed by combining an Internal Model Control (IMC) based PID Control and adaptive Sliding Mode Control (SMC). The IMC-PID controller is designed for the reformer of the fuel flow rate according to the expected first-order dynamic properties. The adaptive SMC controller of the fuel cell current has been designed using the constant plus proportional rate reaching law. The parameters of the SMC controller are adaptively tuned according to the response of the fuel flow rate control system. When the power output controller feeds back the current references to these two controllers, the coordinating controllers system works in a system-wide way. The simulation results of the PEMFC power plant demonstrate the effectiveness of the proposed method. 2009 ISA. Published by Elsevier Ltd. All rights reserved.

  17. PEMFC Performance with Metal Bipolar Plates Depending on the Channel Dimension

    Directory of Open Access Journals (Sweden)

    Kwon Kuikam

    2016-01-01

    Full Text Available Bipolar plates of a proton exchange membrane fuel cell (PEMFC play an important role in removing liquid phase water as a by-product in order to facilitate the reaction between fuel and oxygen. A great amount of effort has been made to improve the performance of a fuel cell such as maximum current density or maximum power, by improving water removability of a bipolar plate. Most of the studies, however, are conducted numerically because of the complexity of analysing gas and liquid and the poor manufacturability of graphite bipolar plates. In this proceeding, we demonstrate that the performance of a PEMFC with metal bipolar plates can be enhanced by reducing the dimension of the channel. Bipolar plates were machined with stainless steel (type 316L to have three different channel size (1000 μm, 500 μm and 300 μm and the performance of each assembled cells were tested. As a result, the maximum power density and the maximum current density increased by 25%.

  18. Characterization of self-assembled electrodes based on Au-Pt nanoparticles for PEMFC application

    Energy Technology Data Exchange (ETDEWEB)

    Valenzuela, E. [Politecnica Univ. de Chiapas, Tuxtla Gutierrez, Chiapas (Mexico). Energia y Sustentabilidad; Sebastian, P.J. [Politecnica Univ. de Chiapas, Chiapas (Mexico). Energia y Sustentabilidad; Centro de Investigacion en Energia, UNAM, Morelos (Mexico); Gamboa, S.A. [Centro de Investigacion en Energia, UNAM, Morelos (Mexico); Pal, U. [Inst. de Fisica, Universidad Autonoma de Puebla Univ., Puebla (Mexico). Inst. de Fisica; Gonzalez, I. [Autonoma Metropolitana Univ. (Mexico). Dept. de Quimica

    2008-07-01

    This paper reported on a study in which membrane electrode assemblies (MEAs) were fabricated by depositing Au, Pt and AuPt nanoparticles on Nafion 115 membrane for use in a proton exchange membrane fuel cell (PEMFC). A Rotating Disc Electrode (RDE) was used to measure the nanoparticle catalyst activity. After deposition of the nanoparticles on the membrane, the surface was studied by Scanning Electron Microscopy (SEM) and Energy Dispersive Spectroscopy (EDS). The membrane proton conduction process was studied by Electrochemical Impedance Spectroscopy (EIS) with the 4 probe technique. The MEAs fabricated with Nafion/Metal membranes were evaluated in a PEMFC under standard conditions. Colloidal solutions were used to prepare self-assembled electrodes with nanoparticles deposited on Nafion membrane. The particles deposited on Nafion showed good stability and had homogeneous distribution along the membrane surface. The impedance results revealed an increase in the membrane proton resistance of the self-assembled electrodes compared to unmodified Nafion. The Au-Pt nanoparticles were obtained by chemical reduction. The nanoparticle size in the three systems was about 2 nm. The self-assembled electrodes performed well in standard conditions. The optimum colloidal concentration and immersion time must be determined in order to obtain good catalytic activity and high membrane conductance. The self-assembled Nafion/AuPt had the best open circuit potential (887 mV). The Au and Pt self-assemblies showed a similar performance in terms of maximum power and maximum current density. The performance of the Nafion/Au self-assembly was influenced more by ohmic losses, particularly in the membrane. The maximum power generation was obtained at 0.35 V. The mass transport losses increased after this value, thereby affecting the efficiency of the PEMFC. 2 figs.

  19. Planar array stack design aided by rapid prototyping in development of air-breathing PEMFC

    Science.gov (United States)

    Chen, Chen-Yu; Lai, Wei-Hsiang; Weng, Biing-Jyh; Chuang, Huey-Jan; Hsieh, Ching-Yuan; Kung, Chien-Chih

    The polymer electrolyte membrane fuel cell (PEMFC) is one of the most important research topics in the new and clean energy area. The middle or high power PEMFCs can be applied to the transportation or the distributed power system. But for the small power application, it is needed to match the power requirement of the product generally. On the other hand, the direct methanol fuel cell (DMFC) is one of the most common type that researchers are interested in, but recently the miniature or the micro-PEMFCs attract more attention due to their advantages of high open circuit voltage and high power density. The objective of this study is to develop a new air-breathing planar array fuel cell stacked from 10 cells made by rapid prototyping technology which has potential for fast commercial design, low cost manufacturing, and even without converters/inverters for the system. In this paper, the main material of flow field plates is acrylonitrile-butadiene-styrene (ABS) which allows the fuel cell be mass-manufactured by plastic injection molding technology. The rapid prototyping technology is applied to construct the prototype and verify the practicability of the proposed stack design. A 10-cell air-breathing miniature PEMFC stack with a volume of 6 cm × 6 cm × 0.9 cm is developed and tested. Its segmented membrane electrode assembly (MEA) is designed with the active surface area of 1.3 cm × 1.3 cm in each individual MEA. The platinum loading at anode and cathode are 0.2 mg cm -2 and 0.4 mg cm -2, respectively. Results show that the peak power densities of the parallel connected and serial connected stack are 99 mW cm -2 at 0.425 V and 92 mW cm -2 at 4.25 V, respectively under the conditions of 70 °C relative saturated humidity (i.e., dew point temperature), ambient temperature and free convection air. Besides, the stack performance is increased under forced convection. If the cell surface air is blown by an electric fan, the peak power densities of parallel connected and

  20. Planar array stack design aided by rapid prototyping in development of air-breathing PEMFC

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Chen-Yu.; Lai, Wei-Hsiang [Institute of Aeronautics and Astronautics, National Cheng Kung University, No.1, Ta-Hsueh Road, Tainan 701 (China); Weng, Biing-Jyh; Chuang, Huey-Jan; Hsieh, Ching-Yuan; Kung, Chien-Chih [Chung-Shan Institute of Science and Technology, Materials and Electro-Optics Research Division, P.O. Box No. 90008-8-3 Lung-Tan, Tao-Yuan 325 (China)

    2008-04-15

    The polymer electrolyte membrane fuel cell (PEMFC) is one of the most important research topics in the new and clean energy area. The middle or high power PEMFCs can be applied to the transportation or the distributed power system. But for the small power application, it is needed to match the power requirement of the product generally. On the other hand, the direct methanol fuel cell (DMFC) is one of the most common type that researchers are interested in, but recently the miniature or the micro-PEMFCs attract more attention due to their advantages of high open circuit voltage and high power density. The objective of this study is to develop a new air-breathing planar array fuel cell stacked from 10 cells made by rapid prototyping technology which has potential for fast commercial design, low cost manufacturing, and even without converters/inverters for the system. In this paper, the main material of flow field plates is acrylonitrile-butadiene-styrene (ABS) which allows the fuel cell be mass-manufactured by plastic injection molding technology. The rapid prototyping technology is applied to construct the prototype and verify the practicability of the proposed stack design. A 10-cell air-breathing miniature PEMFC stack with a volume of 6 cm x 6 cm x 0.9 cm is developed and tested. Its segmented membrane electrode assembly (MEA) is designed with the active surface area of 1.3 cm x 1.3 cm in each individual MEA. The platinum loading at anode and cathode are 0.2 mg cm{sup -2} and 0.4 mg cm{sup -2}, respectively. Results show that the peak power densities of the parallel connected and serial connected stack are 99 mW cm{sup -2} at 0.425 V and 92 mW cm{sup -2} at 4.25 V, respectively under the conditions of 70 C relative saturated humidity (i.e., dew point temperature), ambient temperature and free convection air. Besides, the stack performance is increased under forced convection. If the cell surface air is blown by an electric fan, the peak power densities of

  1. A Neural Non-linear Predictive Control for PEM-FC

    Directory of Open Access Journals (Sweden)

    M. Cirrincione

    2005-06-01

    Full Text Available This paper deals with the application of non-linear predictive control with neural networks to Proton Exchange Membrane Fuel Cells (PEM-FC. The control objective is to regulate the cell voltage, acting on the hydrogen pressure, trying to reduce the variation of the input control variable. An analysis of the non-linearities of the fuel cell stack has been carried out, making use of a suitable fuel cell model. The non-linear predictive control has been implemented by several neural networks (multi value perceptrons, after dividing the operating domain into three areas according to the cell current value (low loads, quasi-linear zone and high loads.Simulation results have been provided and discussed, showing the goodness of the proposed non-linear control technique in reducing the variations of hydrogen pressure.

  2. A fractal model for predicting permeability and liquid water relative permeability in the gas diffusion layer (GDL) of PEMFCs

    Science.gov (United States)

    He, Guangli; Zhao, Zongchang; Ming, Pingwen; Abuliti, Abudula; Yin, Caoyong

    In this study, a fractal model is developed to predict the permeability and liquid water relative permeability of the GDL (TGP-H-120 carbon paper) in proton exchange membrane fuel cells (PEMFCs), based on the micrographs (by SEM, i.e. scanning electron microscope) of the TGP-H-120. Pore size distribution (PSD), maximum pore size, porosity, diameter of the carbon fiber, pore tortuosity, area dimension, hydrophilicity or hydrophobicity, the thickness of GDL and saturation are involved in this model. The model was validated by comparison between the predicted results and experimental data. The results indicate that the water relative permeability in the hydrophobicity case is much higher than in the hydrophilicity case. So, a hydrophobic carbon paper is preferred for efficient removal of liquid water from the cathode of PEMFCs.

  3. Assembly and performance testing of a MEMS-based {mu}PEMFC with the help of a spiral micrometer

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Xigui; Zhang, Jian; Li, Xinxin; Xia, Baojia [Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, Room 807, 8th Building, 865 Changning Road, Shanghai 200050 (China); Wang, Tao [Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, Room 807, 8th Building, 865 Changning Road, Shanghai 200050 (China); Shanghai Institute of Space Power-Sources, Shanghai 200381 (China); Zheng, Dan [Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, Room 807, 8th Building, 865 Changning Road, Shanghai 200050 (China); Shanghai Institute of Technology, Shanghai 200233 (China)

    2008-12-15

    In this work, a feasible and simple method of assembling a micro MEMS-based {mu}PEMFC (about 0.35 ml in volume and 0.65 g in weight) with the help of a spiral micrometer was proposed. The micrometer provided a constant pressure between the two flow field plates and MEA in assembling for a short term while a special epoxy resin was applied to seal the cell and provide long term pressure between the above components after removing the micrometer. Tests showed that the as-assembled cell had a reasonable performance, which was proved by the linear polarization and EIS experiments. The long term behavior of the {mu}PEMFC was stable in general except for some fluctuation along time. We concluded that this fluctuation was due to a combined effect of heat produced and water management, which the as-assembled {mu}PEMFC has its own ability to adjust. More importantly, this experiment demonstrated the full feasibility and great promise of assembling {mu}FCs with the help of a spiral micrometer. (author)

  4. Assembly and performance testing of a MEMS-based {mu}PEMFC with the help of a spiral micrometer

    Energy Technology Data Exchange (ETDEWEB)

    Zhang Xigui [Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, Room 807, 8th Building, 865 Changning Road, Shanghai 200050 (China)], E-mail: zhangxigui@mail.sim.ac.cn; Zhang Jian [Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, Room 807, 8th Building, 865 Changning Road, Shanghai 200050 (China); Wang Tao [Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, Room 807, 8th Building, 865 Changning Road, Shanghai 200050 (China); Shanghai Institute of Space Power-Sources, Shanghai 200381 (China); Zheng Dan [Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, Room 807, 8th Building, 865 Changning Road, Shanghai 200050 (China); Shanghai Institute of Technology, Shanghai 200233 (China); Li Xinxin; Xia Baojia [Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, Room 807, 8th Building, 865 Changning Road, Shanghai 200050 (China)

    2008-12-15

    In this work, a feasible and simple method of assembling a micro MEMS-based {mu}PEMFC (about 0.35 ml in volume and 0.65 g in weight) with the help of a spiral micrometer was proposed. The micrometer provided a constant pressure between the two flow field plates and MEA in assembling for a short term while a special epoxy resin was applied to seal the cell and provide long term pressure between the above components after removing the micrometer. Tests showed that the as-assembled cell had a reasonable performance, which was proved by the linear polarization and EIS experiments. The long term behavior of the {mu}PEMFC was stable in general except for some fluctuation along time. We concluded that this fluctuation was due to a combined effect of heat produced and water management, which the as-assembled {mu}PEMFC has its own ability to adjust. More importantly, this experiment demonstrated the full feasibility and great promise of assembling {mu}FCs with the help of a spiral micrometer.

  5. Measurement of polarization curve and development of a unique semi-empirical model for description of PEMFC and DMFC performances

    Directory of Open Access Journals (Sweden)

    M. SHAKERI

    2011-06-01

    Full Text Available In this study, a single polymer electrolyte membrane fuel cell (PEMFC in H2/ /O2 form with an effective dimension of 5 cm5 cm as well as a single direct methanol fuel cell (DMFC with a dimension of 10 cm10 cm were fabricated. In an existing test station, the voltage-current density performances of the fabricated PEMFC and DMFC were examined under various operating conditions. As expected, DMFC showed a lower electrical performance which can be attributed to the slower methanol oxidation rate in comparison to the hydrogen oxidation. The results obtained from the cell operation indicated that the temperature has a great effect on the cell performance. At 60 C, the best power output was obtained for PEMFC. There was a drop in the cell voltage beyond 60 C, which can be attributed to the reduction of water content inside the membrane. For DMFC, the maximum power output resulted at 64 C. Increasing oxygen stoichiometry and total cell pressure had a marginal effect on the cell performance. The results also revealed that the cell performance improved by increasing pressure differences between the anode and cathode. A unified semi-empirical thermodynamic based model was developed to describe the cell voltage as a function of current density for both kinds of fuel cells. The model equation parameters were obtained through a nonlinear fit to the experimental data. There was a good agreement between the experimental data and the model predicted cell performance for both types of fuel cells.

  6. Low temperature operation and influence parameters on the cold start ability of portable PEMFCs

    Science.gov (United States)

    Oszcipok, M.; Zedda, M.; Riemann, D.; Geckeler, D.

    The start up behaviour of PEM fuel cells below 0 °C is one of the most challenging tasks to be solved before commercialisation. The automotive industry started to develop solutions to reduce the start up time of fuel cell systems in the middle of the nineties. The strategies varied from catalytic combustion of hydrogen on the electrode catalyst to fuel starvation or external stack heating via cooling loops to increase the stack temperature. Beside the automotive sector the cold start ability is as well important for portable PEMFC applications for outdoor use. But here the cold start issue is even more complicated, as the fuel cell system should be operated as passive as possible. Below 0 °C freezing of water inside the PEMFC could form ice layers in the electrode and in the gas diffusion layer. Therefore the cell reaction is limited or even inhibited. Product water during the start up builds additional barriers and leads to a strong decay of the output power at isothermal operating conditions. In order to find out which operational and hardware parameters affect this decay, potentiostatic experiments on single cells were performed at isothermal conditions. These experiments comprise investigations of the influence of membrane thickness and different GDL types as well as the effect of gas flow rates and humidification levels of the membrane. As pre stage to physical based models, empirical based prediction models are used to gain a better understanding of the main influence parameters during cold start. The results are analysed using the statistical software Cornerstone 4.0. The experience of single cell investigations are compared to start up behaviour of portable fuel cell stacks which are operated in a climate chamber at different ambient temperatures below 0 °C. Additional flow sharing problems in the fuel cell stack could be seen during cold start up experiments.

  7. Dynamic modeling of a methanol reformer-PEMFC stack system for analysis and design

    Science.gov (United States)

    Stamps, Andrew T.; Gatzke, Edward P.

    Considerable effort has been devoted to the modeling of proton exchange membrane fuel cells (PEMFCs) as well as fuel processing units (FPUs). Many of these models consider only steady state analysis; the available dynamic models typically operate only in simple open loop configurations. However, a liquid fuel processor/PEMFC stack power unit for vehicular application will require tight integration and regulation of multiple units in order to function economically and reliably. Moreover, vehicular operation is inherently dynamic in nature, so traditional steady state process design approaches will be of limited value. This work addresses a minimum set of subcomponents necessary for modeling an overall vehicular power system. Additionally, the integration and control of these sub-units is addressed so that the unit can be operated as needed in a vehicular application by following a reference power trajectory. A number of design and operational parameters can be adjusted and the impact on system performance studied. Based on this preliminary analysis, heuristics are developed for optimal operation and design.

  8. Simulation and Optimization of Air-Cooled PEMFC Stack for Lightweight Hybrid Vehicle Application

    Directory of Open Access Journals (Sweden)

    Jingming Liang

    2015-01-01

    Full Text Available A model of 2 kW air-cooled proton exchange membrane fuel cell (PEMFC stack has been built based upon the application of lightweight hybrid vehicle after analyzing the characteristics of heat transfer of the air-cooled stack. Different dissipating models of the air-cooled stack have been simulated and an optimal simulation model for air-cooled stack called convection heat transfer (CHT model has been figured out by applying the computational fluid dynamics (CFD software, based on which, the structure of the air-cooled stack has been optimized by adding irregular cooling fins at the end of the stack. According to the simulation result, the temperature of the stack has been equally distributed, reducing the cooling density and saving energy. Finally, the 2 kW hydrogen-air air-cooled PEMFC stack is manufactured and tested by comparing the simulation data which is to find out its operating regulations in order to further optimize its structure.

  9. NASA PEMFC Development Background and History

    Science.gov (United States)

    Hoberecht, Mark

    2011-01-01

    NASA has been developing proton-exchange-membrane (PEM) fuel cell power systems for the past decade, as an upgraded technology to the alkaline fuel cells which presently provide power for the Shuttle Orbiter. All fuel cell power systems consist of one or more fuel cell stacks in combination with appropriate balance-of-plant hardware. Traditional PEM fuel cells are characterized as flow-through, in which recirculating reactant streams remove product water from the fuel cell stack. NASA recently embarked on the development of non-flow-through fuel cell systems, in which reactants are dead-ended into the fuel cell stack and product water is removed by internal wicks. This simplifies the fuel cell power system by eliminating the need for pumps to provide reactant circulation, and mechanical water separators to remove the product water from the recirculating reactant streams. By eliminating these mechanical components, the resulting fuel cell power system has lower mass, volume, and parasitic power requirements, along with higher reliability and longer life. Four vendors have designed and fabricated non-flow-through fuel cell stacks under NASA funding. One of these vendors is considered the "baseline" vendor, and the remaining three vendors are competing for the "alternate" role. Each has undergone testing of their stack hardware integrated with a NASA balance-of-plant. Future Exploration applications for this hardware include primary fuel cells for a Lunar Lander and regenerative fuel cells for Surface Systems.

  10. Corrosion kinetics of 316L stainless steel bipolar plate with chromiumcarbide coating in simulated PEMFC cathodic environment

    Directory of Open Access Journals (Sweden)

    N.B. Huang

    Full Text Available Stainless steel with chromium carbide coating is an ideal candidate for bipolar plates. However, the coating still cannot resist the corrosion of a proton exchange membrane fuel cell (PEMFC environment. In this work, the corrosion kinetics of 316L stainless steel with chromium carbide is investigated in simulated PEMFC cathodic environment by combining electrochemical tests with morphology and microstructure analysis. SEM results reveal that the steel’s surface is completely coated by Cr and chromium carbide but there are pinholes in the coating. After the coated 316L stainless steel is polarized, the diffraction peak of Fe oxide is found. EIS results indicate that the capacitive resistance and the reaction resistance first slowly decrease (2–32 h and then increase. The potentiostatic transient curve declines sharply within 2000 s and then decreases slightly. The pinholes, which exist in the coating, result in pitting corrosion. The corrosion kinetics of the coated 316L stainless steel are modeled and accords the following equation: i0 = 7.6341t−0.5, with the corrosion rate controlled by ion migration in the pinholes. Keywords: PEMFC, Metal bipolar plate, Chromium carbide coating, Corrosion kinetics, Pitting corrosion

  11. Experimental analysis of the effects of the operating variables on the performance of a single PEMFC

    International Nuclear Information System (INIS)

    Santarelli, M.G.; Torchio, M.F.

    2007-01-01

    This paper shows and discusses the results obtained after an experimental session devoted to characterization of the behavior of a single proton exchange membrane fuel cell (PEMFC) with variation of the values of six operation variables: cell temperature; anode flow temperature in saturation and dry conditions; cathode flow temperature in saturation and dry conditions; and reactants pressure. The fuel cell employed for the experiments is a single PEMFC with a 25 cm 2 Nafion[reg] 115 membrane. As expected, a higher cell temperature increases the membrane conductivity and the exchange current density with an improvement of the cell behaviour. An increase in the reactant saturation temperature also leads to a better performance, especially in the case of low and medium loads. Conversely, in the case of a low cell temperature, it is better to reduce the water inlet mass flow at high loads to avoid electrode flooding. With an increase of the reactant operating pressure, the maximum of the power curve shifts to higher current densities, and this could be linked to the corresponding shift of the limiting current density. A combined effect of humidification and operating pressure was observed: the increase of operating pressure did not offer a significant improvement when the reactants were dry, while leading to improvements when a partial humidification (only at the anode) was adopted. The best improvements due to a pressure increase were observed when both anode and cathode are humidified. Finally, some tests of other authors at the same operation conditions have been considered, and a comparison has been done

  12. Forced Air-Breathing PEMFC Stacks

    Directory of Open Access Journals (Sweden)

    K. S. Dhathathreyan

    2012-01-01

    Full Text Available Air-breathing fuel cells have a great potential as power sources for various electronic devices. They differ from conventional fuel cells in which the cells take up oxygen from ambient air by active or passive methods. The air flow occurs through the channels due to concentration and temperature gradient between the cell and the ambient conditions. However developing a stack is very difficult as the individual cell performance may not be uniform. In order to make such a system more realistic, an open-cathode forced air-breathing stacks were developed by making appropriate channel dimensions for the air flow for uniform performance in a stack. At CFCT-ARCI (Centre for Fuel Cell Technology-ARC International we have developed forced air-breathing fuel cell stacks with varying capacity ranging from 50 watts to 1500 watts. The performance of the stack was analysed based on the air flow, humidity, stability, and so forth, The major advantage of the system is the reduced number of bipolar plates and thereby reduction in volume and weight. However, the thermal management is a challenge due to the non-availability of sufficient air flow to remove the heat from the system during continuous operation. These results will be discussed in this paper.

  13. Low cost PEMFC generator manufacturing line. The competitiveness and trustability strategy

    Energy Technology Data Exchange (ETDEWEB)

    Ferreira, Valdemar Stelita; Souza, Adler de; Ferreira, Mauricio S. [NovoCell Energy Systems S.A., Santa Barbara D' Oeste, SP (Brazil)], Email: valdemar.stelita@novocell.ind.br; Muschellack, Erich [Idee Technologies Ltda, Sao Paulo, SP (Brazil)

    2010-07-01

    Concepts of Lean Manufacturing Lines for Polymer Electrolyte Membrane Fuel Cells (PEMFC) have been searched for the last twenty years, with no fully success so far. As this is considered around the world the last barrier to spread the hydrogen economy for universities and science institutions to the normal life of people, we at NovoCell decided six years ago to develop and test all key aspects that can help making it by a 'Low Cost, Feasible and Reliable Production Process'. The present work is a demonstration of the results we achieved, the main characteristics of the prototypes produced from the lines and that will be the base for our commercial operation starting next year. (author)

  14. Platinum-TM (TM = Fe, Co) alloy nanoparticles dispersed nitrogen doped (reduced graphene oxide-multiwalled carbon nanotube) hybrid structure cathode electrocatalysts for high performance PEMFC applications.

    Science.gov (United States)

    Vinayan, B P; Ramaprabhu, S

    2013-06-07

    The efforts to push proton exchange membrane fuel cells (PEMFC) for commercial applications are being undertaken globally. In PEMFC, the sluggish kinetics of oxygen reduction reactions (ORR) at the cathode can be improved by the alloying of platinum with 3d-transition metals (TM = Fe, Co, etc.) and with nitrogen doping, and in the present work we have combined both of these aspects. We describe a facile method for the synthesis of a nitrogen doped (reduced graphene oxide (rGO)-multiwalled carbon nanotubes (MWNTs)) hybrid structure (N-(G-MWNTs)) by the uniform coating of a nitrogen containing polymer over the surface of the hybrid structure (positively surface charged rGO-negatively surface charged MWNTs) followed by the pyrolysis of these (rGO-MWNTs) hybrid structure-polymer composites. The N-(G-MWNTs) hybrid structure is used as a catalyst support for the dispersion of platinum (Pt), platinum-iron (Pt3Fe) and platinum-cobalt (Pt3Co) alloy nanoparticles. The PEMFC performances of Pt-TM alloy nanoparticle dispersed N-(G-MWNTs) hybrid structure electrocatalysts are 5.0 times higher than that of commercial Pt-C electrocatalysts along with very good stability under acidic environment conditions. This work demonstrates a considerable improvement in performance compared to existing cathode electrocatalysts being used in PEMFC and can be extended to the synthesis of metal, metal oxides or metal alloy nanoparticle decorated nitrogen doped carbon nanostructures for various electrochemical energy applications.

  15. Hybrid Nano composite Membranes for PEMFC Applications

    International Nuclear Information System (INIS)

    Niepceron, F.

    2008-03-01

    This work aims at validating a new concept of hybrid materials for the realization of proton exchange membranes, an essential constituent of PEM fuel cells. The originality of this nano-composite hybrid concept corresponds to a separation of the membrane's properties. We investigated the preparation of composite materials based on an inert, relatively low cost, polymer matrix (PVDF-HFP) providing the mechanical stability embedding inorganic fillers providing the necessary properties o f proton-conduction and water retention. The first step of this work consisted in the modification of fumed silica to obtain a proton-conducting filler. An ionic exchange capacity (CEI) equal to 3 meq/g was obtained by the original grafting of sodium poly(styrene-sulfonate) chains from the surface of particles. Nano-composite hybrid membranes PVDF-HFP/functionalized silica were accomplished by a film casting process. The coupling of the morphological and physicochemical analyses validated the percolation of the inorganic phase for 30 wt.% of particles. Beyond 40 % of loading, measured protonic conductivity is higher than the reference membrane Nafion 112. Finally, these membranes presented high performances, above 0.8 W/cm 2 , in single-cell fuel cell tests. A compromise is necessary according to the rate of loading between performances in fuel cell and mechanical properties of the membrane. 50 % appeared as best choice with, until 90 C, a remarkable thermal stability of the performances. (author)

  16. Search for ideal metal hydrides for PEMFC applications

    International Nuclear Information System (INIS)

    Perng, T.-P.; Shen, C.-C.

    2004-01-01

    'Full text:' Previously, an LmNi5-based alloy was prepared and its hydrogenation properties were studied. In order to make use of such a type of metal hydride for application in PEMFC, the room-temperature desorption pressure has to be adjusted to 1-2atm and the cyclic stability has to be maintained. In this study, the same alloy was partially substituted with Al and cyclic hydrogenation was conducted with different hydrogen loadings up to 3000 cycles at room temperature. The saturated hydrogen loadings in equilibrium were controlled at H/M = 0.75 and 1.0. The P-C-T curves after 1000, 2000, and 3000 cycles of test were collected at T=30, 50, and 70 o C. After 3000 cycles, it is observed that the maximum hydrogenation capacities of the samples for the loadings of 0.75 and 1.0 are reduced to 0.93 and 0.91, respectively. The plateaus do not change much for T=30 and 50 o C, but become little sloped without observable split at 70 o C. X-ray diffraction analysis shows that the strains associated with repeated hydrogenation are isotropic for all samples. Both unsubstituted and Al-substituted alloys were then used to store hydrogen in a small cylinder with a diameter 10mm and length of 40 mm. The cylinder was connected to a small PEMFC for discharge test at room temperature. More than 540ml H2 was released at below 2atm and discharged to a capacity of 1200mAh. The hydrogenation properties of the alloys and design of the hydrogen storage cylinder for application in small portable PEMFCs for electronic devices are evaluated. The effect of Al substitution and hydrogen loading on cyclic hydrogenation property of the LmNi5-based alloy is also discussed. (author)

  17. Internal currents in PEMFC during start-up or shut-down

    Energy Technology Data Exchange (ETDEWEB)

    Maranzana, G.; Lottin, O.; Moyne, C.; Dillet, J.; Lamibrac, A.; Mainka, J.; Didierjean, S. [Nancy Univ. - CNRS (France). LEMTA

    2010-07-01

    Experiments show that the internal currents that occur during PEMFC start-up can reach up to 1 Acm{sup -2}. This is far more important than the expected order of magnitude of the current densities associated with carbon oxidation, which is only of a few mAcm{sup -2}. The predominant phenomenon that explains the internal currents is the charge and discharge of the double layer capacitances. A simple model with constant values of the electric parameters yields numerical results close to the experimental ones. It also explains the transient voltage rise (over the steady state open circuit voltage) that is sometimes observed experimentally shortly after the fuel cell start up. (orig.)

  18. Membrane morphological study nanostructured based hydrophobic/hydrophilic applied in devices of PEMFC

    International Nuclear Information System (INIS)

    Loureiro, Felipe Augusto M.; Dahmouche, K; Rocco, Ana Maria

    2015-01-01

    The increasingly high energy demand generated by the increase of world population and consumption of fuels based on non-renewable sources has stimulated, in recent decades, the development of alternatives with less environmental impact and are based on renewable sources. Among these, the fuel cells (FC) have extremely promising possibilities. For the development of FC with market viability, it is necessary to obtain materials with optimized properties, among which the proton conducting membranes. In this work, we developed semi-interpenetrating polymer membranes (SIPN) based on diglycidyl ether of bisphenol-A (DGEBA) and polyethyleneimine (PEI), aiming their application in PEMFC. The membranes nanostructure was studied by AFM and SAXS means and it was identified ordinate hydrophobic/hydrophilic nano domains, which have determined the membrane properties, specially the proton conductivity. (author)

  19. An investigation on the electrocatalytic properties of polypyrrole films on the kinetics of oxygen reduction reaction in PEMFC

    Energy Technology Data Exchange (ETDEWEB)

    Saremi, M.; Sharifi Asl, S.; Kazemi, Sh. [Tehran Univ., Tehran (Iran, Islamic Republic of). School of Metallurgy and Material Science Engineering

    2008-07-01

    A proton exchange membrane (PEM) fuel cell has high power density, low weight, very short start-up time and no leakage of electrolytes. However, there are some disadvantages when operating the PEM fuel cell at room temperature. Many studies involving the widespread commercial use of Pt-based electrocatalysts search for low-cost electrocatalysts for the oxygen reduction reaction. In recent years, much attention has been placed on the use of electrocatalysis for the conducting polymer electrode. Polypyrrole has attracted much attention as an advanced conducting material because of its good environmental stability, easy synthesis and high conductivity. This study examined the effect of the polypyrrole catalyst in a PEMFC cathode. The electropolymerization of pyrrole was carried out in a 3-electrode cell using pure hydrogen and oxygen as the reactants. Tests were carried out at room temperature and cell impedance was measured. The polymer was formed galvanostatically in a 0.1 M pyrrole with a 0.15 KCl aqueous solution with a 20 mA/cm{sup 2} current density. The effect of operating voltage and oxygen mass transport was examined by EIS method, which separates these two phenomena. The study showed that polypyrrole has a catalytic effect for oxygen reduction reaction in PEMFC comparable to a Pt catalyzed electrode. Although the cell potential with polypyrrole was slightly lower than a Pt coated cell, it was found to be more economical. 8 refs., 2 figs.

  20. Quantum jumps in the PEMFC science and technology from the 1960s to the year 2000. Part II. Engineering, technology development and application aspects

    Science.gov (United States)

    Costamagna, Paola; Srinivasan, Supramaniam

    The technology of proton exchange membrane fuel cells (PEMFCs) has now reached the test-phase, and engineering development and optimization are vital in order to achieve to the next step of the evolution, i.e. the realization of commercial units. This paper highlights the most important technological progresses in the areas of (i) water and thermal management, (ii) scale-up from single cells to cell stacks, (iii) bipolar plates and flow fields, and (iv) fuel processing. Modeling is another aspect of the technological development, since modeling studies have significantly contributed to the understanding of the physico-chemical phenomena occurring in a fuel cell, and also have provided a valuable tool for the optimization of structure, geometry and operating conditions of fuel cells and stacks. The 'quantum jumps' in this field are reviewed, starting from the studies at the electrode level up to the stack and system size, with particular emphasis on (i) the 'cluster-network' model of perfluorosulfonic membranes, and the percolative dependence of the membrane proton conductivity on its water content, (ii) the models of charge and mass transport coupled to electrochemical reaction in the electrodes, and (iii) the models of water transport trough the membrane, which have been usefully applied for the optimization of water management of PEMFCs. The evolution of PEMFC applications is discussed as well, starting from the NASA's Gemini Space Flights to the latest developments of fuel cell vehicles, including the evolutions in the areas of portable power sources and residential and building applications.

  1. Optimization of a High Temperature PEMFC micro-CHP System by Formulation and Application of a Process Integration Methodology

    DEFF Research Database (Denmark)

    Arsalis, Alexandros; Nielsen, Mads Pagh; Kær, Søren Knudsen

    2013-01-01

    A 1 kWe micro combined heat and power (CHP) system based on high temperature proton exchange membrane fuel cell (PEMFC) technology is modeled and optimized by formulation and application of a process integration methodology. The system can provide heat and electricity for a singlefamily household......, the heat exchange network (HEN) annual cost is minimized. The results show the high potential of the proposed model since high efficiencies are accomplished. The net electrical efficiency and total system efficiency, based on lower heating value (LHV), are 35.2% and 91.1%, respectively. The minimized total...... annual cost of the HEN is $8,147 year–1....

  2. Micro Galvanic Cell To Generate PtO and Extend the Triple-Phase Boundary during Self-Assembly of Pt/C and Nafion for Catalyst Layers of PEMFC.

    Science.gov (United States)

    Long, Zhi; Gao, Liqin; Li, Yankai; Kang, Baotao; Lee, Jin Yong; Ge, Junjie; Liu, Changpeng; Ma, Shuhua; Jin, Zhao; Ai, Hongqi

    2017-11-08

    The self-assembly powder (SAP) with varying Nafion content was synthesized and characterized by XRD, XPS, HRTEM, and mapping. It is observed that the oxygen from oxygen functional groups transfers to the surface of Pt and generate PtO during the process of self-assembly with the mechanism of micro galvanic cell, where Pt, carbon black, and Nafion act as the anode, cathode and electrolyte, respectively. The appearance of PtO on the surface of Pt leads to a turnover of Nafion structure, and therefore more hydrophilic sulfonic groups directly contact with Pt, and thus the triple-phase boundary (TPB) has been expanded.

  3. Modification of the liquid cooling channel of PEMFCs for their operation with dry reactant gases

    International Nuclear Information System (INIS)

    Shyu, Jin-Cherng; Hsueh, Kan-Lin; Tsau, Fanghei; Chen, Fa-Lin

    2011-01-01

    In order to tackle both water and thermal problems, a modified PEMFC is proposed in the present study for its operation with dry reactant gases via the modification of liquid cooling channel with circulating liquid electrolyte. Fuel cell with both circulating liquid electrolyte and solid polymer membrane operated with either dry or humidified H 2 /O 2 is compared in the present study at temperatures of 40, 50, 65, and 80 o C, respectively. The measured E-I data show that such single cell can be operated at 80 o C without humidification. Besides, a semi-empirical equation to predict the current/voltage relationship, and the electrochemical impedance method are also employed in the present study for cell resistance analysis. The analysis results show that the high interfacial resistance should be one of the major reasons for the inferior performance of the present cell. Based on the discovery, an improvement of the present fuel cell is further proposed by Nafion ionomer spreading on the electrode before the assembly of membrane and electrode. The maximum power density of the cell after electrode treatment reaches 75 mW/cm 2 for dry H 2 /O 2 operation at 0.4 V, which is almost threefold improvement compared with that without electrode treatment.

  4. Enhanced MEA Performance for PEMFCs under Low Relative Humidity and Low Oxygen Content Conditions via Catalyst Functionalization

    Energy Technology Data Exchange (ETDEWEB)

    Xin, Le; Yang, Fan; Xie, Jian; Yang, Zhiwei; Kariuki, Nancy N.; Myers, Deborah J.; Peng, Jui-Kun; Wang, Xiaohua; Ahluwalia, Rajesh K.; Yu, Kang; Ferreira, Paulo J.; Bonastre, Alex Martinez; Fongalland, Dash; Sharman, Jonathan

    2017-01-01

    This work demonstrates that functionalizing annealed-Pt/Ketjen black EC300j (a-Pt/KB) and dealloyed-PtNi/Ketjen black EC300j (d-PtNi/KB) catalysts using p-phenyl sulfonic acid can effectively enhance performance in the membrane electrode assemblies (MEAs) of proton exchange membrane fuel cells (PEMFCs). The functionalization increased the size of both Pt and PtNi catalyst particles and resulted in the further leaching of Ni from the PtNi catalyst while promoting the formation of nanoporous PtNi nanoparticles. The size of the SO3H-Pt/KB and SO3H-PtNi/KB carbon-based aggregates decreased dramatically, leading to the formation of catalyst layers with narrower pore size distributions.MEA tests highlighted the benefits of the surface functionalization, in which the cells with SO3H-Pt/KB and SO3H-PtNi/KB cathode catalysts showed superior high current density performance under reduced RH conditions, in comparison with cells containing annealed Pt/KB (a-Pt/KB) and de-alloyed PtNi/KB (d-PtNi/KB) catalysts. The performance improvement was particularly evident when using reactant gases with low relative humidity, indicating that the hydrophilic functional groups on the carbon improved the water retention in the cathode catalyst layer. These results show a new avenue for enhancing catalyst performance for the next generation of catalytic materials for PEMFCs.

  5. Studies of performance degradation of a high temperature PEMFC based on H 3PO 4-doped PBI

    Science.gov (United States)

    Liu, Gang; Zhang, Huamin; Hu, Jingwei; Zhai, Yunfeng; Xu, Dongyan; Shao, Zhi-gang

    In this paper, a 600 h life test of a high temperature PEMFC based on phosphoric acid (H 3PO 4)-doped polybenzimidazole (PBI) (H 3PO 4/PBI HT-PEMFC) at a current density of 714 mA cm -2 (the beginning 510 h continuous test) and 300 mA cm -2 (the last 90 h intermittent test) was carried out. After the life test, degradation of the MEA occurred. The H 2 crossover rate through the PBI membrane and the open circuit voltage (OCV) of the cell were tested with time. The results showed that, at the beginning of 510 h continuous test, the PBI membrane did not show much physical degradation, but during the last 90 h test there was a remarkable physical degradation which resulted in a higher H 2 crossover. The catalysts, PBI membranes and the membrane electrode assemblies (MEAs) before and after the life test were comprehensively examined by transmission electron microscopy (TEM), scanning electron microscopy (SEM) and energy-dispersive spectroscopy (EDS). TEM results showed that the particle size of the Pt/C catalysts in the anode and cathode increased from 3.72 to 7.40 and 8.39 nm, respectively. SEM images of MEA in cross-section revealed that the PBI membrane became thin after the life test. EDS analysis implied the leaching of H 3PO 4 from the PBI membrane had occurred. Therefore, we conclude that physical degradation of PBI membrane, agglomeration of the electrocatalysts (both anode and cathode) and the leaching of H 3PO 4 from the PBI membrane were responsible for the performance degradation of the H 3PO 4/PBI HT-PEMFC.

  6. Influence of Sintering Temperature on Mechanical and Physical properties of Mill Scale based Bipolar Plates for PEMFC

    Science.gov (United States)

    Khaerudini, Deni S.; Berliana, Rina; Prakoso, Gatra B.; Insiyanda, Dita R.; Alva, Sagir

    2018-03-01

    This work concerns the utilization of mill scale, a by-product of iron and steel formed during the hot rolling of steel, as a potential material for use as bipolar plates in proton exchange membrane fuel cells (PEMFCs). On the other hand, mill scale is considered a very rich in iron source having characteristic required such as for current collector in bipolar plate and would significantly contribute to lower the overall cost of PEMFC based fuel cell systems. In this study, the iron reach source of mill scale powder, after sieving of 150 mesh, was mechanically alloyed with the aluminium source containing 30 wt.% using a shaker mill for 3 h. The mixed powders were then pressed at 300 MPa and sintered at various temperatures of 400, 450 and 500 °C for 1 h under inert gas atmosphere. The structural changes of powder particles during mechanical alloying and after sintering were studied by x-ray diffractometry, scanning electron microscopy (SEM) with energy dispersive X-ray spectroscopy (EDX), microhardness measurement, and density - porosity analysis. The details of the performance variation of three different sintering conditions can be preliminary explained by the metallographic and crystallographic structure and phase analysis as well as sufficient mechanical strength of the sintered materials was presented in this report.

  7. MEIO AMBIENTE E DESENVOLVIMENTO

    Directory of Open Access Journals (Sweden)

    Suely Salgueiro Chacon

    2009-12-01

    Full Text Available O objetivo deste artigo é resgatar elementos para subsidiar uma reflexão crítica sobre o modelo de desenvolvimento econômico prevalente na sociedade e as relações com o meio ambiente, sob a ameaça que ronda o destino da espécie humana, conforme afirmação de Lovelock (2006, p. 20 sobre o conceito de desenvolvimento sustentável: “uma ideia adorável se a tivéssemos aplicado 200 anos atrás, quando havia um bilhão de pessoas no mundo. Agora é tarde demais. Não há mais espaço para nenhum tipo de desenvolvimento. A humanidade tem que regredir”. Este artigo apresenta a evolução do conceito de desenvolvimento econômico sob a ótica da sustentabilidade, e interliga temas como: o ambientalismo, aglutinador de distintos pensamentos sobre as relações entre a sociedade e a natureza; o movimento ambiental, a fundamentar a disseminação do conceito de desenvolvimento sustentável, e a gestão ambiental, abordada como prática orientada pelo conceito de desenvolvimento sustentável.

  8. Proton Exchange Membrane Fuel Cells Applied for Transport Sector

    DEFF Research Database (Denmark)

    Hosseinzadeh, Elham; Rokni, Masoud

    2010-01-01

    A thermodynamic analysis of a PEMFC (proton exchange membrane fuel cell) is investigated. PEMFC may be the most promising technology for fuel cell automotive systems, which is operating at quite low temperatures, (between 60 to 80℃). In this study the fuel cell motive power part of a lift truck has...

  9. Flexible and Lightweight Fuel Cell with High Specific Power Density.

    Science.gov (United States)

    Ning, Fandi; He, Xudong; Shen, Yangbin; Jin, Hehua; Li, Qingwen; Li, Da; Li, Shuping; Zhan, Yulu; Du, Ying; Jiang, Jingjing; Yang, Hui; Zhou, Xiaochun

    2017-06-27

    Flexible devices have been attracting great attention recently due to their numerous advantages. But the energy densities of current energy sources are still not high enough to support flexible devices for a satisfactory length of time. Although proton exchange membrane fuel cells (PEMFCs) do have a high-energy density, traditional PEMFCs are usually too heavy, rigid, and bulky to be used in flexible devices. In this research, we successfully invented a light and flexible air-breathing PEMFC by using a new design of PEMFC and a flexible composite electrode. The flexible air-breathing PEMFC with 1 × 1 cm 2 working area can be as light as 0.065 g and as thin as 0.22 mm. This new PEMFC exhibits an amazing specific volume power density as high as 5190 W L -1 , which is much higher than traditional (air-breathing) PEMFCs. Also outstanding is that the flexible PEMFC retains 89.1% of its original performance after being bent 600 times, and it retains its original performance after being dropped five times from a height of 30 m. Moreover, the research has demonstrated that when stacked, the flexible PEMFCs are also useful in mobile applications such as mobile phones. Therefore, our research shows that PEMFCs can be made light, flexible, and suitable for applications in flexible devices. These innovative flexible PEMFCs may also notably advance the progress in the PEMFC field, because flexible PEMFCs can achieve high specific power density with small size, small volume, low weight, and much lower cost; they are also much easier to mass produce.

  10. Effect of Particle Size and Operating Conditions on Pt3Co PEMFC Cathode Catalyst Durability

    Directory of Open Access Journals (Sweden)

    Mallika Gummalla

    2015-05-01

    Full Text Available The initial performance and decay trends of polymer electrolyte membrane fuel cells (PEMFC cathodes with Pt3Co catalysts of three mean particle sizes (4.9 nm, 8.1 nm, and 14.8 nm with identical Pt loadings are compared. Even though the cathode based on 4.9 nm catalyst exhibited the highest initial electrochemical surface area (ECA and mass activity, the cathode based on 8.1 nm catalyst showed better initial performance at high currents. Owing to the low mass activity of the large particles, the initial performance of the 14.8 nm Pt3Co-based electrode was the lowest. The performance decay rate of the electrodes with the smallest Pt3Co particle size was the highest and that of the largest Pt3Co particle size was lowest. Interestingly, with increasing number of decay cycles (0.6 to 1.0 V, 50 mV/s, the relative improvement in performance of the cathode based on 8.1 nm Pt3Co over the 4.9 nm Pt3Co increased, owing to better stability of the 8.1 nm catalyst. The electron microprobe analysis (EMPA of the decayed membrane-electrode assembly (MEA showed that the amount of Co in the membrane was lower for the larger particles, and the platinum loss into the membrane also decreased with increasing particle size. This suggests that the higher initial performance at high currents with 8.1 nm Pt3Co could be due to lower contamination of the ionomer in the electrode. Furthermore, lower loss of Co from the catalyst with increased particle size could be one of the factors contributing to the stability of ECA and mass activity of electrodes with larger cathode catalyst particles. To delineate the impact of particle size and alloy effects, these results are compared with prior work from our research group on size effects of pure platinum catalysts. The impact of PEMFC operating conditions, including upper potential, relative humidity, and temperature on the alloy catalyst decay trends, along with the EMPA analysis of the decayed MEAs, are reported.

  11. PEMFC performance of MEAS based on Nafion{sup R} and sPSEBS hybrid membranes

    Energy Technology Data Exchange (ETDEWEB)

    Fernandez-Carretero, F.J.; Compan, V. [Univ, Politecnica de Valencia, Valencia (Spain). Dept. Termodinamica Aplicada; Suarez, K.; Solorza, O. [Inst. Politecnico Nacional, Centro de Investigacion y de Estudios Avanzados, Mexico City (Mexico). Dept. de Quimica; Riande, E. [Inst. de Ciencia y Tecnologia de Polimeros, Madrid (Spain)

    2010-07-15

    Important scientific, technical and economic problems must be solved before widespread commercialization of polymer electrolyte membrane fuel cells (PEMFC). The main issues facing the development of commercial low temperature fuel cells are the synthesis of efficient solid electrolytes separating the anode from the cathode as well as the development of cheaper catalysts for fuel oxidation. This study involved the preparation of hybrid membranes based on Nafion 117 and sulfonated Calprene H6120 containing partially sulfonated inorganic fillers such as silica, SBA-15 and sepiolite. The feasibility of using the membranes as polyelectrolytes for low temperature fuel cells was then evaluated. The water uptake of Nafion hybrid membranes is 1/3 to 1/4 of that in composite membranes based on sulfonated Calprene H6120. The proton conductivity of Nafion 117 hybrid membranes-electrode assemblies is nearly 1/5 of the pristine Nafion membrane assembly. Sulfonated Calprene H6120 hybrid membranes typically have better proton conductivity than the Nafion 117 composites. The performance of fuel cells containing different MEAs was examined by measuring their polarization curves in different operating conditions. The kinetic parameters governing the voltage dependence on current density were also estimated. It was concluded that the superior performance of the fuel cells with MEAs of NAF-SEP, sPSEBS-SIL and sPSEBS-SBA is not due to the membranes themselves, but to the kinetic processes that occur at the electrodes, which in this study were less efficient for fuel cells with the Nafion MEA. 34 refs., 3 tabs., 9 figs.

  12. A new catalyst layer based on in situ pore generation of sulfonated poly(ether ether ketone) for PEMFC

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Wan-Keun; Sung, Kyung A; Oh, Keun-Hwan; Choo, Min-Ju; Park, Jung-Ki [Department of Chemical and Biomolecular Engineering and WCU Energy Science and Engineering, Korea Advanced Institute of Science and Technology, 373-1, Guseong-dong, Yuseong-gu, Daejeon 305-701 (Korea); Cho, Kuk Young [Division of Advanced Materials Engineering, Kongju National University, 275, Budae-dong, Cheonan, Chungnam 303-717 (Korea); Cho, Ki-Yun [Fuel Cell Vehicle Team, Hyundai Motor Company and Kia Motors Corp., 104, Mabuk-Dong, Giheung-Gu, Yongin-Si, Gyunggi-Do 446-912 (Korea)

    2009-08-15

    A new concept of in situ pore generation to reduce water flooding in cathode catalyst layer (CCL) of polymer electrolyte membrane fuel cell (PEMFC) is proposed with the introduction of water soluble poly(ethylene glycol) (PEG) as a porogen to CCL based on sulfonated poly(ether ether ketone) (sPEEK). In this new type of CCL, PEG is directly removed by water produced during the cathode reaction. The new CCL exhibited much higher cell performance especially in mass transport limitation region compared to the pristine sPEEK-CCL. In addition, the presence of PEG in the new CCL lowered the glass transition temperature of the sPEEK binder, and it could improve the transference of catalyst layer onto the polymer electrolyte membrane. (author)

  13. Asymmetric bi-layer PFSA membranes as model systems for the study of water management in the PEMFC.

    Science.gov (United States)

    Peng, Z; Peng, A Z; Morin, A; Huguet, P; Lanteri, Y; Deabate, S

    2014-10-14

    New bi-layer PFSA membranes made of Nafion® NRE212 and Aquivion™ E79-05s with different equivalent weights are prepared with the aim of managing water repartition in the PEMFC. The membrane water transport properties, i.e. back-diffusion and electroosmosis, as well as the electrochemical performances, are compared to those of state-of-art materials. The actual water content (the inner water concentration profile across the membrane thickness) is measured under operation in the fuel cell by in situ Raman microspectroscopy. The orientation of the equivalent weight gradient with respect to the water external gradient and to the proton flow direction affects the membrane water content, the water transport ability and, thus, the fuel cell performances. Higher power outputs, related to lower ohmic losses, are observed when the membrane is assembled with the lower equivalent weight layer (Aquivion™) at the anode side. This orientation, corresponding to enhanced water transport by back-flow while electroosmosis remains unaffected, results in the higher hydration of the membrane and of the anode active layer during operation. Also, polarization data suggest a different water repartition in the fuel cell along the on-plane direction. Even if the interest in multi-layer PFSA membranes as perspective electrolytes for PEMFCs is not definitively attested, these materials appear to be excellent model systems to establish relationships between the membrane transport properties, the water distribution in the fuel cell and the electrochemical performances. Thanks to the micrometric resolution, in situ Raman microspectroscopy proves to be a unique tool to measure the actual hydration of the membrane at the surface swept by the hydrated feed gases during operation, so that it can be used as a local probe of the water concentration evolution along the gas distribution channels according to changing working conditions.

  14. Valores e Desenvolvimento Humano

    NARCIS (Netherlands)

    F. Comim (Flavio); A. Macedo de Jesus (Anderson); R.C.B Oliveira (Raissa); A. Davison (Anna); S. Galeno (Sabrina); A.C.V. Ribeiro (Ana)

    2010-01-01

    markdownabstractA primeira parte desse Relatório de Desenvolvimento Humano do Brasil 2009/2010 começa com a descrição de um amplo processo de consulta aberta à sociedade, denominada Brasil Ponto a Ponto, para a escolha do tema do relatório. A Campanha Brasil Ponto a Ponto teve por objetivo

  15. Pt based PEMFC catalysts prepared from colloidal particle suspensions--a toolbox for model studies.

    Science.gov (United States)

    Speder, Jozsef; Altmann, Lena; Roefzaad, Melanie; Bäumer, Marcus; Kirkensgaard, Jacob J K; Mortensen, Kell; Arenz, Matthias

    2013-03-14

    A colloidal synthesis approach is presented that allows systematic studies of the properties of supported proton exchange membrane fuel cell (PEMFC) catalysts. The applied synthesis route is based on the preparation of monodisperse nanoparticles in the absence of strong binding organic stabilizing agents. No temperature post-treatment of the catalyst is required rendering the synthesis route ideally suitable for comparative studies. We report work concerning a series of catalysts based on the same colloidal Pt nanoparticle (NP) suspension, but with different high surface area (HSA) carbon supports. It is shown that for the prepared catalysts the carbon support has no catalytic co-function, but carbon pre-treatment leads to enhanced sticking of the Pt NPs on the support. An unwanted side effect, however, is NP agglomeration during synthesis. By contrast, enhanced NP sticking without agglomeration can be accomplished by the addition of an ionomer to the NP suspension. The catalytic activity of the prepared catalysts for the oxygen reduction reaction is comparable to industrial catalysts and no influence of the particle size is found in the range of 2-5 nm.

  16. Development of a Stochastically-driven, Forward Predictive Performance Model for PEMFCs

    Science.gov (United States)

    Harvey, David Benjamin Paul

    A one-dimensional multi-scale coupled, transient, and mechanistic performance model for a PEMFC membrane electrode assembly has been developed. The model explicitly includes each of the 5 layers within a membrane electrode assembly and solves for the transport of charge, heat, mass, species, dissolved water, and liquid water. Key features of the model include the use of a multi-step implementation of the HOR reaction on the anode, agglomerate catalyst sub-models for both the anode and cathode catalyst layers, a unique approach that links the composition of the catalyst layer to key properties within the agglomerate model and the implementation of a stochastic input-based approach for component material properties. The model employs a new methodology for validation using statistically varying input parameters and statistically-based experimental performance data; this model represents the first stochastic input driven unit cell performance model. The stochastic input driven performance model was used to identify optimal ionomer content within the cathode catalyst layer, demonstrate the role of material variation in potential low performing MEA materials, provide explanation for the performance of low-Pt loaded MEAs, and investigate the validity of transient-sweep experimental diagnostic methods.

  17. Characterization of self-assembled electrodes based on Au-Pt nanoparticles for PEMFC application

    Energy Technology Data Exchange (ETDEWEB)

    Valenzuela, E. [Univ. Politecnica de Chiapas (Mexico). Energia y Sustentabilidad; Sebastian, P.J.; Gamboa, S.A.; Joseph, S. [Univ. Nacional Autonoma de Mexico, Morelos (Mexico). Centrode Investigacion en Energia; Pal, U. [Univ. Autonoma de Puebla, Pue (Mexico). Inst. de Fisica; Gonzalez, I. [Univ. Autonoma Metropolitana, Mexico City (Mexico). Dept. de Quimica

    2010-07-01

    This paper described the synthesis and characterization of gold (Au), platinum (Pt) and Au-Pt nanoparticles impregnated on a Nafion membrane in a proton exchange membrane fuel cell (PEMFC). The aim of the study was to fabricate the membrane electrode assembly (MEA) by depositing the nanoparticles on the membrane using an immersion technique. Scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) were used to study the deposition process. Electrochemical impedance spectroscopy (EIS) was used to study the membrane proton conduction process. An elemental mapping analysis was performed in order to study the location of the Au and Pt in the self-assemblies. Results of the study showed that the particles deposited on the Nafion had good stability and a homogenous distribution along the membrane surface. The particles showed a direct relation in size and location with the hydrophilic and hydrophobic distribution phases of the membrane. The main membrane resistance was located between the membrane and the electrolyte. The self-assembled electrodes demonstrated a good performance at standard conditions. 33 refs., 4 tabs., 11 figs.

  18. A strain-controlled C2N monolayer membrane for gas separation in PEMFC application

    Science.gov (United States)

    Deng, Shengwei; Hu, Hui; Zhuang, Guilin; Zhong, Xing; Wang, Jianguo

    2018-05-01

    Ultrathin membranes with controllable pore sizes have great potential to realize high-selectivity gas separation at low energy cost, especially for those mixtures with narrow size distributions. Using a combination of van der Waals-corrected density functional theory (DFT) calculations and molecular dynamics (MD) simulation, we examine the separation ability of biaxial stretched monolayer C2N nanosheets which is applied to the O2 separation from CO/CO2/O2 mixtures in the cathode of proton exchange membrane fuel cells (PEMFC). The DFT calculations show that the diffusion energy barrier for molecules passing through the membrane followed by CO, CO2 and O2 in descending order, and an overall decrease of energy barriers due to the widen the pore size is observed with the increase of applied strains. Furthermore, MD results show that the nanosheet can effectively purify O2 from CO2 and CO with a strain from 8% to 10%. It confirms that the selectivity is determined by the electronic structure related interaction in addition to the kinetic diameter of individual molecules. The O2 permeability is improved progressively with further increase of strain, and small amount of CO2 begins to permeate through the nanosheet at relatively large strain, while the excellent CO isolation is not compromised until the theoretical maximum strain.

  19. Technological Monitoring Applied to Survey-Based on Brazilian Patent Applications about PEMFC

    Directory of Open Access Journals (Sweden)

    Deysimar de Souza Carvalho

    2011-06-01

    Full Text Available The present study aims to show the importance of patents as an instrument of technological innovation and to assess the relevance of technology of PEMFC in Brazil by means of the technological monitoring methodology from 1996 to 2005. This study used different Industrial Property Databases (INPI-BR, ESPACENET and DWPI, in order to retrieve the BR applications in each database. Relevant keywords as “fuel cell” were used in combination with specific IPC (H01M8 in order to assess the main applicants, countries, IPCs and technological innovation over time. In Brazil, the country holding more requests in this area is the United States (US with 53,7% of the patent applications, while Brazil (BR accounts for 4,4% of the total requests. It was also observed that the North-American company, UTC Fuel Cells comes on top of the list and that there were no patent applications of Brazilian origin (BR in other countries.

  20. Insights on the SO2 Poisoning of Pt3Co/VC and Pt/VC Fuel Cell Catalysts

    Science.gov (United States)

    2010-01-01

    catalyst is performed at the cathode of proton exchange membrane fuel cells ( PEMFCs ) in order to link previously reported results at the elec- trode...stripping voltammetry and underpotential deposition (upd) of copper adatoms. Then the performance of PEMFC cathodes employing 30wt.% Pt3Co/VC and 50wt.% Pt/VC...proton exchange membrane fuel cells( PEMFCs )in order to link previously reported results at the elec- trode/solution interface to the FC environment. First

  1. 3-Dimensional Computational Fluid Dynamics Modeling of Solid Oxide Fuel Cell Using Different Fuels

    Science.gov (United States)

    2011-01-01

    major types of fuel cells in practice are listed below: Polymer Electrolyte Membrane Fuel Cell ( PEMFC ) Alkaline Fuel cell (AFC) Phosphoric Acid...Material Operating Temperature (oC) Efficiency (%) PEMFC H2, Methanol, Formic Acid Hydrated Organic Polymer < 90 40-50 AFC Pure H2 Aqueous

  2. Development of solid oxide fuel cells (SOFC); Desenvolvimento de celulas a combustivel do tipo oxido solido (SOFC)

    Energy Technology Data Exchange (ETDEWEB)

    Souza, F.M.B. de; Carvalho, L.F.V. de; Alencar, M.G de; Boaventura, J.S. [Universidade Federal da Bahia (DFQ/UFBA), Salvador, BA (Brazil). Dept de Fisico-Quimica. Grupo de energia e Ciencias dos Materiais], e-mail: bventura@ufba.br

    2008-07-01

    The most promising technology for generating electric power, with reduced environmental impact, is the fuel cell. This technology is virtually non-polluting and the fuel supplies can be renewable. Therefore is necessary to study the technique of preparing the entire anode / electrolyte / cathode to optimize its operation. There are still major challenges to making the SOFC economically viable. The key is the improvement of manufacturing of its components and use of materials that can simultaneously reduce costs and reduce the temperature of operation. Among the properties of the cell, was shown the dependence of the efficiency of the device on the properties of the electrolyte, particularly its thickness. The mixture of YSZ with GDC in the composition of the anode and electrolyte aims to obtain a material with greater ionic conductivity. After sintering the cell was characterized by scanning electron microscopy (SEM). (author)

  3. Ice-Crystallization Kinetics during Fuel-Cell Cold-Start

    OpenAIRE

    Dursch, Thomas James

    2014-01-01

    Proton-exchange-membrane fuel cells (PEMFCs) show promise in automotive applications because of their high efficiency, high power density, and potentially low emissions. To be successful in automobiles, PEMFCs must permit rapid startup with minimal energy from subfreezing temperatures, known as cold-start. In a PEMFC, reduction of oxygen to water occurs in the cathode catalyst layer (CL). Under subfreezing conditions, water generated during startup solidifies and hinders access of gaseous oxy...

  4. Durability Improvement of Pt/RGO Catalysts for PEMFC by Low-Temperature Self-Catalyzed Reduction.

    Science.gov (United States)

    Sun, Kang Gyu; Chung, Jin Suk; Hur, Seung Hyun

    2015-12-01

    Pt/C catalyst used for polymer electrolyte membrane fuel cells (PEMFCs) displays excellent initial performance, but it does not last long because of the lack of durability. In this study, a Pt/reduced graphene oxide (RGO) catalyst was synthesized by the polyol method using ethylene glycol (EG) as the reducing agent, and then low-temperature hydrogen bubbling (LTHB) treatment was introduced to enhance the durability of the Pt/RGO catalyst. The cyclic voltammetry (CV), oxygen reduction reaction (ORR) analysis, and transmittance electron microscopy (TEM) results suggested that the loss of the oxygen functional groups, because of the hydrogen spillover and self-catalyzed dehydration reaction during LTHB, reduced the carbon corrosion and Pt agglomeration and thus enhanced the durability of the electrocatalyst.

  5. The Role of Non-Conventional Supports for Single-Atom Platinum-Based Catalysts in Fuel-Cell Technology: A Theoretical Surface Science Approach

    Science.gov (United States)

    2013-02-05

    could be a promising catalyst for PEM fuel cells. Introduction: Proton exchange membrane fuel cells ( PEMFCs ) have found wide potential...Unfortunately, due to their high cost and low lifespan, wide-scale commercialization of PEMFCs has been greatly impeded and much effort has been made to...lower its cost as well as to improve its durability over time. In an attempt to alleviate the high-cost associated with conventional PEMFC catalysts

  6. Rapid prototyping methods for the manufacture of fuel cells

    Directory of Open Access Journals (Sweden)

    Dudek Piotr

    2016-01-01

    The potential for the application of this method for the manufacture of metallic bipolar plates (BPP for use in proton exchange membrane fuel cells (PEMFCs is presented and discussed. Special attention is paid to the fabrication of light elements for the construction of PEMFC stacks designed for mobile applications such as aviation technology and unmanned aerial vehicles (UAVs.

  7. Polygeneration system based on PEMFC, CPVT and electrolyzer: Dynamic simulation and energetic and economic analysis

    International Nuclear Information System (INIS)

    Calise, Francesco; Figaj, Rafal Damian; Massarotti, Nicola; Mauro, Alessandro; Vanoli, Laura

    2017-01-01

    Highlights: • A novel polygeneration system is presented. • System includes CPVT collectors, PEM fuel cell, absorption chiller and electrolyzer. • The system provides heating/cooling, domestic hot water, electricity, hydrogen and oxygen. • The system simple payback period is 12.5 years, 5.8 years in case of incentive. • The optimal fuel cell nominal power results 100 kW. - Abstract: This paper presents a dynamic simulation model and an energetic and economic analysis of novel polygeneration system. The system integrates: cogenerative Proton Exchange Membrane Fuel Cell (PEMFC), Concentrated PhotoVoltaic-Thermal (CPVT) collectors, alkaline electrolyzer and single-stage LiBr/H 2 O absorption chiller. The plant is designed to supply electrical energy, space heating or cooling and domestic hot water for a small university building. The system produces hydrogen and oxygen, the first one is stored and then it is supplied to the fuel cell, while the second one is sold. The electrolyzer system is powered only by the CPVT collectors, only a small amount of the solar electrical energy is available to the user. Such electric energy along with the one produced by the PEM fuel cell are used by the user and/or supplied to the grid. The system is designed and dynamically simulated using TRNSYS software package. This study is based on a model previously developed by the authors. In particular, the system was modified in order to implement the new components (CPVT, alkaline electrolyzer, hydrogen and oxygen system) in this work. Special attention is paid to the control strategy of the proposed system in order to achieve the optimal system configuration. Daily, weekly and yearly results carried out with the dynamic simulation are presented. Finally, a sensitivity analysis was performed in order to determine the system performance as a function of the main design parameters. The energetic and economic analysis shows that the system can ensure significant energy savings and

  8. Humidifying system design of PEMFC test platform based on the mixture of dry and wet air

    Directory of Open Access Journals (Sweden)

    Tiancai Ma

    2015-01-01

    Full Text Available Based on the present humidifying system of PEMFC test platform, a novel design based on dry and wet air mixture is proposed. Key parameters are calculated, and test platform is built. Three experiments are implemented to test the performance of proposed design. Results show that the new design can meet the requirements, and realize the quick response and accurate control.

  9. High Pt utilization PEMFC electrode obtained by alternative ion-exchange/electrodeposition.

    Science.gov (United States)

    Chen, Siguo; Wei, Zidong; Li, Hua; Li, Li

    2010-12-14

    High Pt utilization PEMFC electrodes were prepared by an alternative ion-exchange/electrodeposition (AIEE) technique. The results demonstrated that the MEA employing an AIEE electrode with a Pt loading of 0.014 mg Pt cm(-2) exhibits performance approximately 2.2 times larger than that employing a conventional Nafion-bonded Pt/C electrode with a same Pt loading.

  10. SIMULATION OF POROSITY AND PTFE CONTENT IN GAS DIFFUSION LAYER ON PROTON EXCHANGE MEMBRANE FUEL CELL PERFORMANCE

    Directory of Open Access Journals (Sweden)

    NUR H. MASLAN

    2016-01-01

    Full Text Available Numerous research and development activities have been conducted to optimize the operating parameters of a proton exchange membrane fuel cell (PEMFC by experiments and simulations. This study explains the development of a 3D model by using ANSYS FLUENT 14.5 to determine the optimum PEMFC parameters, namely, porosity and polytetrafluoroethylene (PTFE content, in the gas diffusion layer (GDL. A 3D model was developed to analyze the properties and effects of GDL. Simulation results showed that the increase in GDL porosity significantly improved the performance of PEMFC in generating electrical power. However, the performance of PEMFC decreased with increasing PTFE content in GDL. Thus, the PTFE content in the GDL must be optimized and the optimum PTFE content should be 5 wt%. The model developed in this simulation showed good capability in simulating the PEMFC parameters to assist the development process of PEMFC design.

  11. Three-dimensional numerical simulations of water droplet dynamics in a PEMFC gas channel

    Science.gov (United States)

    Zhu, Xun; Sui, P. C.; Djilali, Ned

    The dynamic behavior of liquid water emerging from the gas diffusion layer (GDL) into the gas flow channel of a polymer electrolyte membrane fuel cell (PEMFC) is modeled by considering a 1000 μm long air flow microchannel with a 250 μm × 250 μm square cross section and having a pore on the GDL surface through which water emerges with prescribed flow rates. The transient three-dimensional two-phase flow is solved using Computational fluid dynamics in conjunction with a volume of fluid method. Simulations of the processes of water droplet emergence, growth, deformation and detachment are performed to explicitly track the evolution of the liquid-gas interface, and to characterize the dynamics of a water droplet subjected to air flow in the bulk of the gas channel in terms of departure diameter, flow resistance coefficient, water saturation, and water coverage ratio. Parametric simulations including the effects of air flow velocity, water injection velocity, and dimensions of the pore are performed with a particular focus on the effect of the hydrophobicity of the GDL surface while the static contact angles of the other channel walls are set to 45°. The wettability of the microchannel surface is shown to have a major impact on the dynamics of the water droplet, with a droplet splitting more readily and convecting rapidly on a hydrophobic surface, while for a hydrophilic surface there is a tendency for spreading and film flow formation. The hydrophilic side walls of the microchannel appear to provide some benefit by lifting the attached water from the GDL surface, thus freeing the GDL-flow channel interface for improved mass transfer of the reactant. Higher air inlet velocities are shown to reduce water coverage of the GDL surface. Lower water injection velocities as well as smaller pore sizes result in earlier departure of water droplets and lower water volume fraction in the microchannel.

  12. History of Fuel Cell R&D at Fort Belvoir, Virginia

    Science.gov (United States)

    2008-04-01

    PEMFC but BOP is reduced. In many respects it behaves like a PAFC. MOLTEN CARBONATE FUEL CELL (MCFC) The MCFC operates at high temperature...clean up as required by the PEMFC . It can utilize air cooling without concern electrolyte control which greatly eases BOP issues. The PAFC is highly

  13. The effect of inhomogeneous compression on water transport in the cathode of a PEM fuel cell

    DEFF Research Database (Denmark)

    Olesen, Anders Christian; Berning, Torsten; Kær, Søren Knudsen

    2011-01-01

    A three-dimensional, multi-component, two-fluid model developed in the commercial CFD package CFX 13 (ANSYS inc.), is used to investigate the effect of porous media compression on transport phenomenon of a PEM Fuel cell (PEMFC). The PEMFC model only consist of the cathode channel, gas diffusion...

  14. Model-based fault detection for proton exchange membrane fuel cell ...

    African Journals Online (AJOL)

    In this paper, an intelligent model-based fault detection (FD) is developed for proton exchange membrane fuel cell (PEMFC) dynamic systems using an independent radial basis function (RBF) networks. The novelty is that this RBF networks is used to model the PEMFC dynamic systems and residuals are generated based ...

  15. Development of an Internal Real-Time Wireless Diagnostic Tool for a Proton Exchange Membrane Fuel Cell

    Science.gov (United States)

    Lee, Chi-Yuan; Chen, Chia-Hung; Tsai, Chao-Hsuan; Wang, Yu-Syuan

    2018-01-01

    To prolong the operating time of unmanned aerial vehicles which use proton exchange membrane fuel cells (PEMFC), the performance of PEMFC is the key. However, a long-term operation can make the Pt particles of the catalyst layer and the pollutants in the feedstock gas bond together (e.g., CO), so that the catalyst loses reaction activity. The performance decay and aging of PEMFC will be influenced by operating conditions, temperature, flow and CO concentration. Therefore, this study proposes the development of an internal real-time wireless diagnostic tool for PEMFC, and uses micro-electro-mechanical systems (MEMS) technology to develop a wireless and thin (<50 μm) flexible integrated (temperature, flow and CO) microsensor. The technical advantages are (1) compactness and three wireless measurement functions; (2) elastic measurement position and accurate embedding; (3) high accuracy and sensitivity and quick response; (4) real-time wireless monitoring of dynamic performance of PEMFC; (5) customized design and development. The flexible integrated microsensor is embedded in the PEMFC, three important physical quantities in the PEMFC, which are the temperature, flow and CO, can be measured simultaneously and instantly, so as to obtain the authentic and complete reaction in the PEMFC to enhance the performance of PEMFC and to prolong the service life. PMID:29342832

  16. Development of an Internal Real-Time Wireless Diagnostic Tool for a Proton Exchange Membrane Fuel Cell

    Directory of Open Access Journals (Sweden)

    Chi-Yuan Lee

    2018-01-01

    Full Text Available To prolong the operating time of unmanned aerial vehicles which use proton exchange membrane fuel cells (PEMFC, the performance of PEMFC is the key. However, a long-term operation can make the Pt particles of the catalyst layer and the pollutants in the feedstock gas bond together (e.g., CO, so that the catalyst loses reaction activity. The performance decay and aging of PEMFC will be influenced by operating conditions, temperature, flow and CO concentration. Therefore, this study proposes the development of an internal real-time wireless diagnostic tool for PEMFC, and uses micro-electro-mechanical systems (MEMS technology to develop a wireless and thin (<50 μm flexible integrated (temperature, flow and CO microsensor. The technical advantages are (1 compactness and three wireless measurement functions; (2 elastic measurement position and accurate embedding; (3 high accuracy and sensitivity and quick response; (4 real-time wireless monitoring of dynamic performance of PEMFC; (5 customized design and development. The flexible integrated microsensor is embedded in the PEMFC, three important physical quantities in the PEMFC, which are the temperature, flow and CO, can be measured simultaneously and instantly, so as to obtain the authentic and complete reaction in the PEMFC to enhance the performance of PEMFC and to prolong the service life.

  17. Development of an Internal Real-Time Wireless Diagnostic Tool for a Proton Exchange Membrane Fuel Cell.

    Science.gov (United States)

    Lee, Chi-Yuan; Chen, Chia-Hung; Tsai, Chao-Hsuan; Wang, Yu-Syuan

    2018-01-13

    To prolong the operating time of unmanned aerial vehicles which use proton exchange membrane fuel cells (PEMFC), the performance of PEMFC is the key. However, a long-term operation can make the Pt particles of the catalyst layer and the pollutants in the feedstock gas bond together (e.g., CO), so that the catalyst loses reaction activity. The performance decay and aging of PEMFC will be influenced by operating conditions, temperature, flow and CO concentration. Therefore, this study proposes the development of an internal real-time wireless diagnostic tool for PEMFC, and uses micro-electro-mechanical systems (MEMS) technology to develop a wireless and thin (<50 μm) flexible integrated (temperature, flow and CO) microsensor. The technical advantages are (1) compactness and three wireless measurement functions; (2) elastic measurement position and accurate embedding; (3) high accuracy and sensitivity and quick response; (4) real-time wireless monitoring of dynamic performance of PEMFC; (5) customized design and development. The flexible integrated microsensor is embedded in the PEMFC, three important physical quantities in the PEMFC, which are the temperature, flow and CO, can be measured simultaneously and instantly, so as to obtain the authentic and complete reaction in the PEMFC to enhance the performance of PEMFC and to prolong the service life.

  18. Studies on the efficiency during reactivation of a generation system based on natural gas reformer and a 5 k W fuel cell; Estudos de eficiencia durante reativacao de um sistema de geracao baseado em reformador de gas natural e celula a combustivel de 5 kW

    Energy Technology Data Exchange (ETDEWEB)

    Lopes, Francisco da Costa; Furtado, Jose Geraldo de Melo; Silva Junior, Fernando Rodrigues da; Serra, Eduardo Torres [Centro de Pesquisas de Energia Eletrica (CEPEL), Rio de Janeiro, RJ (Brazil)]. E-mail: fcl@cepel.br

    2008-07-01

    Fuel cell based power generation systems have been pointing as promising technology for stationary applications mainly to supply power to critical loads. Among several types of fuel cells the Polymer Electrolyte Membrane Fuel Cells (PEMFC) are the main type used around the world. Nowadays reformers are widely employed to produce hydrogen for fuel cells. The Fuel Cell Laboratory of CEPEL has a power plant based on a 5 kW PEMFC and a natural gas reformer. For a long time the PEMFC was inoperable due to reformer malfunctioning and during this time the full power availability of PEMFC was lost due to deactivation of its catalytic sites. In most cases this deactivation is reversible. So it was started a reactivation process aiming to recover the full operational condition of the PEMFC unit. During this process the gas flow relationship and efficiency of the reformer were studied. An analysis of the PEMFC reactivation was conducted where it was noted that the reactivation took place as expected. During the reactivation process the PEMFC and the whole system efficiency were analyzed. The results suggest that the PEMFC can reach efficiency compatible with conventional power generation systems thus allowing PEMFC technology to compete with these energy sources in point of efficiency. (author)

  19. Proton exchange fuel cell : the design, construction and evaluation

    Energy Technology Data Exchange (ETDEWEB)

    Heinzen, M.R.; Simoes, G.C.; Da Silva, L. [Univ. do Vale do Itajai, Sao Jose, SC (Brazil). Lab. de Pesquisa em Energia; Fiori, M.A.; Paula, M.M.S. [Univ. do Extremo Sul Catarinense, Santa Catarina (Brazil). Lab. de Sintese de Complexos Multifuncionais; Benavides, R. [Centro de Investigacion en Quimica Aplicada, Coahuila (Mexico)

    2010-07-15

    Polymer electrolyte membrane fuel cells (PEMFC) convert the chemical energy stored in the fuel directly into electrical energy without intermediate steps. The PEMFC operates at a relatively low operating temperature making it a good choice for mobile applications, but a high power density is needed in order to decrease the total weight of the vehicles. This paper presented a simple methodology to construct a PEMFC-type fuel cell, with particular reference to the gaseous diffuser, cell structure, the fixing plate, mounting bracket, gas distribution plates, and the membrane electrode assembly (MEA). The geometric design and meshing of the PEMFC were also described. The electrode was made using graphite with flow-field geometry. The PEMFC was tested for 100 hour of continuous work, during which time the current and voltage produced were monitored in order to evaluate the performance of the PEMFC. The materials used in the preparation of the fuel cell proved to be suitable. There was no loss of efficiency during the tests. The most relevant aspects affecting the PEMFC design were examined in an effort to optimize the performance of the cell. 13 refs., 6 figs.

  20. An Energy Dense-AI-NaBH4-PEMFC Based Power Generator for Unmanned Undersea Vehicles

    Science.gov (United States)

    2016-03-01

    with a stealth operation. The Navy has established several general classes of UUVs to encompass all the possible applications. The power source...meet the Navy most critical objectives: power density, rapid startup, endurance, and stealth . The major shortcoming of PEMFC is that it is very...used for the endothermic steam reforming process in a closed cycle, but careful thermal management is required to prevent the system from overheating

  1. System integration and control strategy analysis of PEMFC car

    International Nuclear Information System (INIS)

    Sun, L.; Chen, Y.; Liu, Y.; Shi, P.

    2004-01-01

    A new fuel car was designed according to the prototype LN2000 hydrogen-oxygen fuel cell car. The new prototype consists of a compact fuel cell engine with separated fuel cell stack, nickel metal hydride battery, a motor with power of 30Kw/100Kw and an inverter with high efficiency. With in the powertrain, a two-shift Planet gear transmission was employed. The power performance was greatly improved. New battery with EMS, new self-developed fuel cell engine, the motor propulsion system and electronic controlled transmission make it feasible to control the whole fuel car automatically and efficiently with optimization. The presents the system integration and the control strategy analysis of the fuel cell car prototype. The paper can be used for reference for engineers in the field of fuel cell vehicle. (author)

  2. Electrical efficiency losses occurred by the air compressor for PEMFC

    International Nuclear Information System (INIS)

    Haubrock, J.; Heideck, G.; Styczynski, Z.

    2006-01-01

    Fuel Cells are characterised by a high efficiency and comparatively small emissions. Depending on their partial load behaviour and their high efficiency, Fuel Cells are well suited for net connected or isolated autonomous energy generators for thermal and electricity power production. Proton Exchange Membrane (PEM) Fuel Cell systems need several external components to produce electricity and thermal power. However, the high theoretical degree of efficiency of 83% is decreased by these components. To reach higher fuel utilisation it is necessary to reduce the energy consumption of these components. In this study, the influence of the air supply compressor on the fuel utilisation is investigated and an optimization strategy was developed. The results were reviewed by a real test set up using an autonomous PEM Fuel Cell system. (authors)

  3. Fuel Cells for Balancing Fluctuation Renewable Energy Sources

    DEFF Research Database (Denmark)

    Mathiesen, Brian Vad

    2007-01-01

    integration can also be preformed with other types of fuel cells than the SOFCs such as PEMFC in micro-CHP. These however have the disadvantage that the efficiency is lower and require pure hydrogen. PEMFCs have advantages for mobile applications replacing internal combustion engines and batteries were...... feasible. For mobile applications the PEMFCs have the advantages that they can compete with internal combustion engines with fast start-up, fast regulation abilities and better efficiencies. In comparison with batteries fuel cells have the advantage that they have higher energy densities and can...

  4. Spontaneous oscillations of cell voltage, power density, and anode exit CO concentration in a PEM fuel cell.

    Science.gov (United States)

    Lu, Hui; Rihko-Struckmann, Liisa; Sundmacher, Kai

    2011-10-28

    The spontaneous oscillations of the cell voltage and output power density of a PEMFC (with PtRu/C anode) using CO-containing H(2) streams as anodic fuels have been observed during galvanostatic operating. It is ascribed to the dynamic coupling of the CO adsorption (poisoning) and the electrochemical CO oxidation (reactivating) processes in the anode chamber of the single PEMFC. Accompanying the cell voltage and power density oscillations, the discrete CO concentration oscillations at the anode outlet of the PEMFC were also detected, which directly confirms the electrochemical CO oxidation taking place in the anode chamber during galvanostatic operating. This journal is © the Owner Societies 2011

  5. Heat science and transport phenomena in fuel cells; Thermique et phenomenes de transport dans les piles a combustible

    Energy Technology Data Exchange (ETDEWEB)

    Liberatore, P.M.; Boillot, M. [Laboratoire des Sciences du Genie Chimique de Nancy, 54 - Vandoeuvre-les-Nancy (France); Bonnet, C.; Didieerjean, S.; Lapicque, F.; Deseure, J.; Lottin, O.; Maillet, D.; Oseen-Senda, J. [Laboratoire d' Energetique et de Mecanique Theorique et Appliquee, 54 - Vandoeuvre Les Nancy (France); Alexandre, A. [Laboratoire d' Etudes Thermiques, ENSMA, 86 Poitiers (France); Topin, F.; Occelli, R.; Daurelle, J.V. [IUSTI / Polytech' Marseille, Institut universitaire des Systemes Thermiques Industriels Ecole, 13 - Marseille (France); Pauchet, J.; Feidt, M. [CEA Grenoble, Groupement pour la recherche sur les echangeurs thermiques (Greth), 38 (France); Voarino, C. [CEA Centre d' Etudes du Ripault, 37 - Tours (France); Morel, B.; Laurentin, J.; Bultel, Y.; Lefebvre-Joud, F. [CEA Grenoble, LEPMI, 38 (France); Auvity, B.; Lasbet, Y.; Castelain, C.; Peerohossaini, H. [Ecole Centrale de Nantes, Laboratoire de Thermocinetique de Nantes (LTN), 44 - Nantes (France)

    2005-07-01

    In this work are gathered the transparencies of the lectures presented at the conference 'heat science and transport phenomena in fuel cells'. The different lectures have dealt with 1)the gas distribution in the bipolar plates of a fuel cell: experimental studies and computerized simulations 2)two-phase heat distributors in the PEMFC 3)a numerical study of the flow properties of the backing layers on the transfers in a PEMFC 4)modelling of the heat and mass transfers in a PEMFC 5)two-phase cooling of the PEMFC with pentane 6)stationary thermodynamic model of the SOFC in the GECOPAC system 7)modelling of the internal reforming at the anode of the SOFC 8)towards a new thermal design of the PEMFC bipolar plates. (O.M.)

  6. High Molecular Weight Polybenzimidazole Membranes for High Temperature PEMFC

    DEFF Research Database (Denmark)

    Yang, Jingshuai; Cleemann, Lars Nilausen; Steenberg, T.

    2014-01-01

    tensile strength of 30.3 MPa at room temperature or 7.3 MPa at 130 °C and a proton conductivity of 0.14 S cm–1 at 160 °C. Fuel cell tests with H2 and air at 160 °C showed high open circuit voltage, power density and a low degradation rate of 1.5 μV h–1 at a constant load of 300 mA cm–2.......High temperature operation of proton exchange membrane fuel cells under ambient pressure has been achieved by using phosphoric acid doped polybenzimidazole (PBI) membranes. To optimize the membrane and fuel cells, high performance polymers were synthesized of molecular weights from 30 to 94 k...

  7. Improvement of proton exchange membrane fuel cell overall efficiency by integrating heat-to-electricity conversion

    Science.gov (United States)

    Xie, Chungang; Wang, Shuxin; Zhang, Lianhong; Hu, S. Jack

    Proton exchange membrane fuel cells (PEMFCs) have shown to be well suited for distributed power generation due to their excellent performance. However, a PEMFC produces a considerable amount of heat in the process of electrochemical reaction. It is desirable to use thermal energy for electricity generation in addition to heating applications. Based on the operating characteristics of a PEMFC, an advanced thermal energy conversion system using "ocean thermal energy conversion" (OTEC) technology is applied to exploit the thermal energy of the PEMFC for electricity generation. Through this combination of technology, this unique PEMFC power plant not only achieves the combined heat and power efficiency, but also adequately utilizes heat to generate more valuable electricity. Exergy analysis illustrates the improvement of overall efficiency and energy flow distribution in the power plant. Analytical results show that the overall efficiency of the PEMFC is increased by 0.4-2.3% due to the thermal energy conversion (TEC) system. It is also evident that the PEMFC should operate within the optimal load range by balancing the design parameters of the PEMFC and of the TEC system.

  8. Economic analysis of direct hydrogen PEM fuel cells in three near-term markets

    International Nuclear Information System (INIS)

    Mahadevan, K.; Stone, H.; Judd, K.; Paul, D.

    2007-01-01

    Direct hydrogen polymer electrolyte membrane fuel cells (H-PEMFCs) offer several near-term opportunities including backup power applications in state and local agencies of emergency response; forklifts in high throughput distribution centers; and, airport ground support equipment. This paper presented an analysis of the market requirements for introducing H-PEMFCs successfully, as well as an analysis of the lifecycle costs of H-PEMFCs and competing alternatives in three near-term markets. It also used three scenarios as examples of the potential for market penetration of H-PEMFCs. For each of the three potential opportunities, the paper presented the market requirements, a lifecycle cost analysis, and net present value of the lifecycle costs. A sensitivity analysis of the net present value of the lifecycle costs and of the average annual cost of owning and operating each of the H-PEMFC opportunities was also conducted. It was concluded that H-PEMFC-powered pallet trucks in high-productivity environments represented a promising early opportunity. However, the value of H-PEMFC-powered forklifts compared to existing alternatives was reduced for applications with lower hours of operation and declining labor rates. In addition, H-PEMFC-powered baggage tractors in airports were more expensive than battery-powered baggage tractors on a lifecycle cost basis. 9 tabs., 4 figs

  9. Engineered Graphene Materials: Synthesis and Applications for Polymer Electrolyte Membrane Fuel Cells.

    Science.gov (United States)

    He, Daping; Tang, Haolin; Kou, Zongkui; Pan, Mu; Sun, Xueliang; Zhang, Jiujun; Mu, Shichun

    2017-05-01

    Engineered graphene materials (EGMs) with unique structures and properties have been incorporated into various components of polymer electrolyte membrane fuel cells (PEMFCs) such as electrode, membrane, and bipolar plates to achieve enhanced performances in terms of electrical conductivity, mechanical durability, corrosion resistance, and electrochemical surface area. This research news article provides an overview of the recent development in EGMs and EGM-based PEMFCs with a focus on the effects of EGMs on PEMFC performance when they are incorporated into different components of PEMFCs. The challenges of EGMs for practical PEMFC applications in terms of production scale, stability, conductivity, and coupling capability with other materials are also discussed and the corresponding measures and future research trends to overcome such challenges are proposed. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  10. Optimization Study of PEMFC stack at elevated temperature

    African Journals Online (AJOL)

    UPUser

    Proton exchange membrane (PEM) fuel cell has many distinctive features that make it an attractive alternative clean energy source, including low start-up, high power density, high efficiency, portability and remote applications. An approach to stem ... have made it one of the most promising clean and highly efficient power.

  11. Stimulated-healing of proton exchange membrane fuel cell catalyst

    NARCIS (Netherlands)

    Latsuzbaia, R.; Negro, E.; Koper, G.J.M.

    2013-01-01

    Platinum nanoparticles, which are used as catalysts in Proton Exchange Membrane Fuel Cells (PEMFC), tend to degrade after long-term operation. We discriminate the following mechanisms of the degradation: poisoning, migration and coalescence, dissolution, and electrochemical Ostwald ripening. There

  12. Mathematical modeling of water mass balance for proton exchange membrane fuel cell

    International Nuclear Information System (INIS)

    Wan Ramli Wan Daud; Kamaruzzaman Sopian; Jaafar Sahari; Nik Suhaimi Mat Hassan

    2006-01-01

    Gas and water management are key to achieving good performance from a proton exchange membrane fuel cell (PEMFC) stack. Water plays a critical role in PEMFC. The proton conductivity is increase with the water content. In order to achieve enough hydration, water is normally introduced into the cell externally by a variety of methods such as liquid injection, steam introduction, and humidification of reactants by passing them through humidifiers before entering the cell. In this paper, mathematical modeling of water mass balance for PEMFC at anode and cathode side are proposed by using external humidification and assume that steady state, constant pressure, constant temperature and gases distribution are uniform

  13. PEMFC contamination model: Foreign cation exchange with ionomer protons

    Science.gov (United States)

    St-Pierre, Jean

    2011-08-01

    A generic, transient fuel cell ohmic loss mathematical model was developed for the case of contaminants that ion exchange with ionomer protons. The model was derived using step changes in contaminant concentration, constant operating conditions and foreign cation transport via liquid water droplets. In addition, the effect of ionomer cations redistribution within the ionomer on thermodynamic, kinetic and mass transport losses and migration were neglected. Thus, a simpler, ideal, ohmic loss case is defined and is applicable to uncharged contaminant species and gas phase contaminants. The closed form solutions were validated using contamination data from a membrane exposed to NH3. The model needs to be validated against contamination and recovery data sets including an NH4+ contaminated membrane exposed to a water stream. A method is proposed to determine model parameters and relies on the prior knowledge of the initial ionomer resistivity. The model expands the number of previously derived cases. Most models in this inventory, derived with the assumption that the reactant is absent, lead to different dimensionless current vs. time behaviors similar to a fingerprint. These model characteristics facilitate contaminant mechanism identification. Separation between membrane and catalyst (electroinactive contaminant) contamination is conceivably possible using additional indicative cell resistance measurements. Contamination is predicted to be significantly more severe under low relative humidity conditions.

  14. Interaction between Nafion ionomer and noble metal catalyst for PEMFCs

    DEFF Research Database (Denmark)

    Andersen, Shuang Ma

    The implement of polymer impregnation in electrode structure (catalyst layer) decreasing the noble metal catalyst loading by a factor of ten , , is one of the essential mile stones in the evolution of Proton Exchange Membrane Fuel Cells’ development among the application of catalyst support...... and electrode deposition etc. In fuel cell reactions, both electrons and protons are involved. Impregnation of Nafion ionomer in catalyst layer effectively increases the proton-electron contact, enlarge the reaction zone, extend the reaction from the surface to the entire electrode. Therefore, the entire...... catalyst layer conducts both electrons and protons so that catalyst utilization in the layer is improved dramatically. The catalyst layer will in turn generate and sustain a higher current density. One of the generally adapted methods to impregnate Nafion into the catalyst layer is to mix the catalysts...

  15. Development of cost innovative BPs for a PEMFC stack for a 1 kW-class residential power generator (RPG) system

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Gil-yong; Jung, Min-kyung; Ryoo, Sung-nam; Ha, Sam-chul [Digital Appliance R and D, LG Electronics, Seoul 153-801 (Korea, Republic of); Park, Myung-seok [LG Solar Energy, Seoul 150-721 (Korea, Republic of); Kim, Sunhoe [Department of New Energy and Resource Engineering, Sangji University, Wonju, Gangwon 220-702 (Korea, Republic of)

    2010-12-15

    In order to satisfy the demands of customers, cost innovation of fuel cell systems is required for the commercialization of the fuel cell. Since the stack is one of the most expensive parts in a fuel cell system, cost reduction of stack is required for fuel cell commercialization. For this effort stainless steel 304 sheets were etched for the flow field and then coated for corrosion resistance. This enables the development of highly cost-effective bipolar plates (BPs) for a Proton Exchange Membrane Fuel Cell (PEMFC) stack of a 1 kW-class for Residential Power Generator (RPG). LG Electronics (LGE) developed a metal stack of 64 cells with the developed BPs and achieved a performance rating of 0.75 V/cell at 200 mA/cm{sup 2}. LGE also achieved a stack volume reduction of 20% compared to a stack of the same specifications consisting of graphite material BPs. The volume decrease can be represented as a cost reduction. LGE achieved the very low cost innovation to 1 USD per cell with cells developed from etched metal BPs. LGE also achieved 500 h of operation with LGE's RPG system; this test is still ongoing. The degradation rate of the stack was 27 {mu}V/hr. The end of life of the stack was estimated at approximately 17,000 h. (author)

  16. Degradation forecast for PEMFC cathode-catalysts under cyclic loads

    Science.gov (United States)

    Moein-Jahromi, M.; Kermani, M. J.; Movahed, S.

    2017-08-01

    Degradation of Fuel Cell (FC) components under cyclic loads is one of the biggest bottlenecks in FC commercialization. In this paper, a novel experimental based algorithm is presented to predict the Catalyst Layer (CL) performance loss during cyclic load. The algorithm consists of two models namely Models 1 and 2. The Model 1 calculates the Electro-Chemical Surface Area (ECSA) and agglomerate size (e.g. agglomerate radius, rt,agg) for the catalyst layer under cyclic load. The Model 2 is the already-existing model from our earlier studies that computes catalyst performance with fixed structural parameters. Combinations of these two Models predict the CL performance under an arbitrary cyclic load. A set of parametric/sensitivity studies is performed to investigate the effects of operating parameters on the percentage of Voltage Degradation Rate (VDR%) with rank 1 for the most influential one. Amongst the considered parameters (such as: temperature, relative humidity, pressure, minimum and maximum voltage of the cyclic load), the results show that temperature and pressure have the most and the least influences on the VDR%, respectively. So that, increase of temperature from 60 °C to 80 °C leads to over 20% VDR intensification, the VDR will also reduce 1.41% by increasing pressure from 2 atm to 4 atm.

  17. Kladná elektroda na bázi MnOx pro PEMFC

    OpenAIRE

    Šmídek, Miroslav

    2011-01-01

    Předkládaná bakalářská práce uvádí do problematiky vodíkových palivových článků a zaměřuje se na nízkoteplotní palivové články s polymerním elektrolytem (PEMFC). Základním zaměřením práce je studium vlastností katalyzátorů na bázi MnOx na reálném palivovém článku typu PEMFC. Výstupem jsou pak změřené charakteristiky takto vytvořeného palivového článku. Construed bachelor work features into problems hydrogen fuel articles and survey on low-temperature fuell elements with polymeric electroly...

  18. High temperature polymer electrolyte membrane fuel cells: Approaches, status, and perspectives

    DEFF Research Database (Denmark)

    This book is a comprehensive review of high-temperature polymer electrolyte membrane fuel cells (PEMFCs). PEMFCs are the preferred fuel cells for a variety of applications such as automobiles, cogeneration of heat and power units, emergency power and portable electronics. The first 5 chapters...... of and motivated extensive research activity in the field. The last 11 chapters summarize the state-of-the-art of technological development of high temperature-PEMFCs based on acid doped PBI membranes including catalysts, electrodes, MEAs, bipolar plates, modelling, stacking, diagnostics and applications....

  19. Do desenvolvimento global ao desenvolvimento local: novas perspectivas do desenvolvimento do turismo

    Directory of Open Access Journals (Sweden)

    Thiliane Meguis

    2015-07-01

    Full Text Available erifica-se que o debate em torno dos conceitos e modelos de desenvolvimento são cada vez mais frequentes atualmente já se percebe maior preocupação voltada principalmente para o bem estar social. Nesse sentido o Turismo de Base Comunitária (TBC será destacado como um paradigma para o desenvolvimento do turismo sustentável, que objetiva a participação social, ressaltando a sua escala “de baixo para cima”, onde a população local é o ator fundamental desse processo. Para maior compreensão deste assunto consideram-se as seguintes questões: o que é desenvolvimento afinal? Como alcança-lo? Para quê? Este trabalho buscará discutir sobre a importância das ações descentralizadoras de participação e democracia para o desenvolvimento do turismo. Acredita-se, que quando as pessoas criam o hábito de se relacionar por diversas razões sociais ela é capaz de promover um bem estar econômico, social e ambiental para os seus envolvidos, que vão além do mero crescimento econômico. Para isso, os assuntos abordados neste trabalho perpassam pela compreensão de desenvolvimento e crescimento econômico, tido por diversos pesquisadores como antônimos, até o entendimento do desenvolvimento local/endógeno. Após está análise teórica, verificar-se-á as suas relações com o desenvolvimento do turismo, em especial o turismo de base comunitária (TBC, bem como, a importância da formulação e implementação de políticas públicas que estejam de acordo com a realidade local. Utiliza-se como método a pesquisa qualitativa, de caráter descritivo para a compressão crítica dos textos, referente aos conceitos destacados.

  20. Gas-liquid two-phase flow behaviors and performance characteristics of proton exchange membrane fuel cells in a short-term microgravity environment

    Science.gov (United States)

    Guo, Hang; Liu, Xuan; Zhao, Jian Fu; Ye, Fang; Ma, Chong Fang

    2017-06-01

    In this work, proton exchange membrane fuel cells (PEMFCs) with transparent windows are designed to study the gas-liquid two-phase flow behaviors inside flow channels and the performance of a PEMFC with vertical channels and a PEMFC with horizontal channels in a normal gravity environment and a 3.6 s short-term microgravity environment. Experiments are conducted under high external circuit load and low external circuit load at low temperature where is 35 °C. The results of the present experimental work demonstrate that the performance and the gas-liquid two-phase flow behaviors of the PEMFC with vertical channels exhibits obvious changes when the PEMFCs enter the 3.6 s short-term microgravity environment from the normal gravity environment. Meanwhile, the performance of the PEMFC with vertical channels increases after the PEMFC enters the 3.6 s short-term microgravity environment under high external circuit load, while under low external circuit load, the PEMFC with horizontal channels exhibits better performance in both the normal gravity environment and the 3.6 s short-term microgravity environment.

  1. Chelating agent-assisted heat treatment of a carbon-supported iron oxide nanoparticle catalyst for PEMFC.

    Science.gov (United States)

    Liu, Shyh-Jiun; Huang, Chia-Hung; Huang, Chun-Kai; Hwang, Weng-Sing

    2009-08-28

    Iron complexes were supported on commercial carbon black and heat treated to create FeO(x)/C catalysts that showed a larger normalized current density and normalized power density than commercial Pt/C catalysts; the coordination number of the iron complexes used affected the formation of the active site for oxygen reduction in PEMFC.

  2. Dynamic simulation of a fuel cell hybrid vehicle during the federal test procedure-75 driving cycle

    International Nuclear Information System (INIS)

    Kang, Sanggyu; Min, Kyoungdoug

    2016-01-01

    Highlights: • Development of a FCHV dynamic model. • Integration of a PEMFC system dynamic model with the electric vehicle model. • Investigation of the dynamic behavior of the FCEV and PEMFC system during FTP-75. • Capturing the dynamic correlation among components in PEMFC system during FTP-75. - Abstract: The dynamic behavior of a proton exchange membrane fuel cell (PEMFC) system is a crucial factor to ensure the safe and effective operation of fuel cell hybrid vehicles (FCHVs). Specifically, water and thermal management are critical to stabilize the performance of the PEMFC during severe load changes. In the present study, the FCHV dynamic model is developed. The dynamic model of the PEMFC system developed by Matlab–Simulink® is integrated into the electric vehicle model embedded in the Amesim®. The dynamic model of the PEMFC system is composed of a PEMFC stack, an air feeding system, and a thermal management system (TMS). The component models of PEMFC, a shell-and-tube gas-to-gas membrane humidifier, and a heat exchanger are validated via a comparison with the experimental data. The FCHV model is simulated during a federal test procedure (FTP)-75 driving cycle. One system configuration and control strategy is adopted to attain optimal water and thermal management in the PEMFC system. The vehicle speed obtained from the FCHV model aptly tracks the target velocity profile of the FTP-75 cycle within an error of ±0.5%. The dynamic behavior and correlation of each component in the PEMFC system is investigated. The mass and heat transfer in the PEMFC, a humidifier, and a heat exchanger are resolved to determine the species concentration and the temperature more accurately with discretization in the flow’s perpendicular direction. Discretization in the flow parallel direction of humidifier and heat exchanger model makes it possible to capture the distribution of the characteristics. The present model can be used to attain the optimization of the system

  3. An assessment of the energetic flows in a commercial PEM fuel-cell system

    International Nuclear Information System (INIS)

    Jovan, Vladimir; Perne, Matija; Petrovcic, Janko

    2010-01-01

    Some primary issues have not yet been fully investigated on the way towards the commercialization of fuel-cell-based systems (FCS), e.g., their actual efficiency, reliability, safety, degradation, maintainability, etc. This article deals with an estimation of the real energetic flows and the corresponding electrical efficiency of a commercial proton-exchange-membrane fuel-cell hydrogen-fed generator set (PEMFCS). The fuel-cell power system considered here is planned to be the source of both electrical and thermal energy in a mobile dwelling container unit with in-built fuel-cell-based cogeneration system, and for the design of a cogeneration unit the actual amount of disposable energy from the PEMFC unit should be estimated. The assessment of the actual energetic flows, the disposable energy and the consequent electrical efficiency of the case-study PEMFCS is carried out using commercial technical data for the PEMFCS.

  4. Development of a 10 kW PEM fuel cell for stationary applications

    Energy Technology Data Exchange (ETDEWEB)

    Barthels, H.; Mergel, J.; Oetjen, H.F. [Institute fuer Energieverfahrenstechnik (IEV), Juelich (Germany)] [and others

    1996-12-31

    A 10 kW Proton Exchange Membrane Fuel Cell (PEMFC) is being developed as part of a long-term energy storage path for electricity in the photovoltaic demonstration plant called PHOEBUS at the Forschungszentrum Julich.

  5. Synthesis and characterisation of alkaline anionic-exchange membranes for direct alcohol fuel cells

    CSIR Research Space (South Africa)

    Nonjola, P

    2007-12-01

    Full Text Available , but the most important being proton exchange membrane fuel cell (PEMFC), which uses an acidic membrane like Nafion (sulfonated fluorocarbon polymers) as an electrolyte. The use of polymer electrolytes represents an interesting path to pursue...

  6. Improved Membrane Materials for PEM Fuel Cell Application

    Energy Technology Data Exchange (ETDEWEB)

    Kenneth A. Mauritz; Robert B. Moore

    2008-06-30

    The overall goal of this project is to collect and integrate critical structure/property information in order to develop methods that lead to significant improvements in the durability and performance of polymer electrolyte membrane fuel cell (PEMFC) materials. This project is focused on the fundamental improvement of PEMFC membrane materials with respect to chemical, mechanical and morphological durability as well as the development of new inorganically-modified membranes.

  7. SPPSU-based hybrid proton conducting polymeric electrolytes for intermediate temperature PEMFCs

    Energy Technology Data Exchange (ETDEWEB)

    Licoccia, Silvia; Di Vona, M. Luisa; D' Epifanio, Alessandra; Ahmed, Zakarya; Bellitto, Serafina; Marani, Debora; Mecheri, Barbara; de Bonis, Catia; Traversa, Enrico [Department of Chemical Science and Technology, University of Rome Tor Vergata, via della Ricerca Scientifica 1, 00133 Rome (Italy); Trombetta, Marcella [Interdisciplinary Center for Biomedical Research (CIR), Laboratory of Biomaterials, Universita ' ' Campus Bio-Medico' ' , via E. Longoni 83, 00155 Rome (Italy)

    2007-05-01

    Polyphenylsulfone (PPSU) was reacted with SiCl{sub 4} to afford silylated telechelic polymers having different inorganic content, which were sulfonated to different degrees (0.05 {<=} DS {<=} 2) using H{sub 2}SO{sub 4} or ClSO{sub 3}Si(CH{sub 3}){sub 3}. A class II organic-inorganic hybrid polymer was then synthesized via cross-linking through Si-O-Si bonds generated by non-hydrolytic sol-gel reactions. The physicochemical properties of the hybrid were suitable for the preparation of self-standing, flexible and homogeneous membranes which were characterized ATR/FTIR spectroscopy demonstrating the formation of covalent bonds between the organic and inorganic components and the absence of dispersed inorganic silicon. The electrochemical performance was analyzed by electrochemical impedance spectroscopy which showed adequately high conductivity values to make the hybrid polymer a suitable candidate for application as electrolyte in PEMFCs operating at T > 100 C. (author)

  8. In-situ measurement of electroosmotic drag coefficient in Nafion membrane for the PEMFC.

    Science.gov (United States)

    Peng, Zhe; Morin, Arnaud; Huguet, Patrice; Schott, Pascal; Pauchet, Joël

    2011-11-10

    A new method based on hydrogen pump has been developed to measure the electroosmotic drag coefficient in representative PEMFC operating conditions. It allows eliminating the back-flow of water which leads to some errors in the calculation of this coefficient with previously reported electrochemical methods. Measurements have been performed on 50 μm thick Nafion membranes both extruded and recast. Contrary to what has been described in most of previous published works, the electroosmotic drag coefficient decreases as the membrane water content increases. The same trend is observed for temperatures between 25 and 80 °C. For the same membrane water content, the electroosmotic drag coefficient increases with temperature. In the same condition, there is no difference in drag coefficient for extruded Nafion N112 and recast Nafion NRE212. These results are discussed on the basis of the two commonly accepted proton transport mechanisms, namely, Grotthus and vehicular.

  9. Proton-Conducting Sulfonated and Phosphonated Polymers and Fuel Cell Membranes by Chemical Modification of Polysulfones

    OpenAIRE

    Lafitte, Benoit

    2007-01-01

    The proton exchange membrane fuel cell (PEMFC) is currently emerging as an efficient and environmentally friendly power source. The technology is very complex and relies ultimately on materials and components which need further development. One of the major hurdles for advancing the PEMFC technology is currently the demand for new durable low-cost polymeric membranes that will allow fuel cell operation at high temperatures without extensive humidification requirements. Thus, the design and pr...

  10. Investigation of water distribution in proton exchange membrane fuel cells via Terahertz imaging

    International Nuclear Information System (INIS)

    Thamboon, P.; Buaphad, P.; Thongbai, C.; Saisud, J.; Kusoljariyakul, K.; Rhodes, M.W.; Vilaithong, T.

    2011-01-01

    Coherent transition radiation in a THz regime generated from a femtosecond electron bunch is explored for its potential use in imaging applications. Due to water sensitivity, the THz imaging experiment is performed on a proton exchange membrane fuel cell (PEMFC) to assess the ability to quantify water in the flow field of the cell. In this investigation, the PEMFC design and the experimental setup for the THz imaging is described. The results of the THz images in the flow field are also discussed.

  11. Overview and benchmark analysis of fuel cell parameters estimation for energy management purposes

    Science.gov (United States)

    Kandidayeni, M.; Macias, A.; Amamou, A. A.; Boulon, L.; Kelouwani, S.; Chaoui, H.

    2018-03-01

    Proton exchange membrane fuel cells (PEMFCs) have become the center of attention for energy conversion in many areas such as automotive industry, where they confront a high dynamic behavior resulting in their characteristics variation. In order to ensure appropriate modeling of PEMFCs, accurate parameters estimation is in demand. However, parameter estimation of PEMFC models is highly challenging due to their multivariate, nonlinear, and complex essence. This paper comprehensively reviews PEMFC models parameters estimation methods with a specific view to online identification algorithms, which are considered as the basis of global energy management strategy design, to estimate the linear and nonlinear parameters of a PEMFC model in real time. In this respect, different PEMFC models with different categories and purposes are discussed first. Subsequently, a thorough investigation of PEMFC parameter estimation methods in the literature is conducted in terms of applicability. Three potential algorithms for online applications, Recursive Least Square (RLS), Kalman filter, and extended Kalman filter (EKF), which has escaped the attention in previous works, have been then utilized to identify the parameters of two well-known semi-empirical models in the literature, Squadrito et al. and Amphlett et al. Ultimately, the achieved results and future challenges are discussed.

  12. O paradigma do desenvolvimento: do mito fundador ao novo desenvolvimento

    Directory of Open Access Journals (Sweden)

    Anete B.L. Ivo

    Full Text Available Este artigo busca historicizar contextos que reorientaram a noção de desenvolvimento, no Brasil, desde os anos 30-80, passando pelo ajuste neoliberal dos anos 90, até inflexões atuais que indagam se o novo intervencionismo massivo e estratégico do Estado em políticas sociais para os mais pobres aponta para um novo modelo de desenvolvimento. A análise apresenta inflexões do modelo cepalino de 50-60 e tenta priorizar dimensões sociais na mediação das contradições entre a economia, a política e o institucional. O fio condutor toma dois vetores analíticos: o tema do conflito (redistributivo e o da integração. O primeiro é assentado nas coalizões das classes e confronto entre atores nacionais e agências multilaterais; e o da integração, na contraface do conflito, considera a abertura das políticas públicas e, também, a inovação de atores sociais e políticos em novos arranjos voltados para os objetivos do bem-estar social e da cidadania, de uma perspectiva mais sustentada.

  13. Lifecycle Cost Assessment of Fuel Cell Technologies for Soldier Power System Applications. Paper and Presentation for the 43rd Power Sources Conference held 8-9 July 2008, Philadelphia, PA

    Science.gov (United States)

    2008-07-09

    PEMFC in Federal Markets,” 2007 Fuel Cell Seminar, San Antonio, TX, 17 October 2007. 7. Fok, K., “Metal Hydride Fuel Cells: Increases in Power...Lauderdale, FL, March 17-20, 2008. 10. Zhao J., et al, “Reclaim/recycle of Pt/C catalysts for PEMFC ,” Energy Conversion and Management, vol. 48...hydrogen PEMFC or SOFC systems – Baratto et al, Journal of Power Sources – Citigroup, Dist. Telecom Backup – Battelle, Fuel Cell Seminar 2007 • Fuel

  14. Mass transport in a PEMFC fuel battery using combinations of monopolar plates and reaction-diffusion medium; Transporte de masa en una pila a combustible tipo PEMFC utilizando combinaciones de platos monopolares y medios de difusion de reactivos

    Energy Technology Data Exchange (ETDEWEB)

    Rosas Paleta, M. G. Araceli [Benemerita Universidad Autonoma de Puebla, Puebla, Puebla (Mexico); Bautista Rodriguez, C. Moises [Alter-Energias Puebla, Puebla (Mexico)] email: celso.bautista@thyssenkrupp.com; Rivera Marquez, J. Antonio; Tepale Ochoa, Nancy [Benemerita Universidad Autonoma de Puebla, Puebla, Puebla (Mexico)

    2009-09-15

    The efficiency of a PEMFC fuel battery is limited due to a variety of mass transport-related phenomena that take place while it is operating. The electromotive force of the PEM fuel battery is related to the generation of concentration gradients resulting from the distribution of the reactants on the active sites of the electrode. The reactant gases supplied to the PEMFC are distributed over the diffusion layer of the electrodes through the channels of the polar plates. They then spread toward the active layer where the semi-reactions take place. Another important aspect is the presence of water molecules, a product of the reaction. When they accumulate, they cover the porosity of the electrodes, involving the reduction in the flow of reactants, even at high current density values and, combined with the diffusion phenomena involved, cause the PEMFC to complete cease functioning. The critical parameters for the transport phenomena are porosity, the diameter of the pore in the diffusion layer and the characteristics of the distribution of the reactants. The present works includes an experimental design of two distribution media and two diffusion media of the reactant gases in a PEMFC, involving three case studies. The results show significantly notable interactions between the diameter of the pore, the type of diffusion layer applied and the type of distributor applied. The combination in the second case significantly reduces the ohmic resistance and moderately reduces the diffusion resistances. While the combination in case three notably increases the ohmic resistance, diffusion resistance is significantly reduced. [Spanish] La eficiencia de una pila a combustible tipo PEMFC es limitada por diversos fenomenos de transporte de masa presentes durante su funcionamiento. La fuerza electromotriz de la pila a combustible tipo PEM esta relacionada con la generacion de gradientes de concentracion los cuales se dan como resultado de la distribucion de los reactivos sobre los

  15. Negligible degradation upon in situ voltage cycling of a PEMFC using an electrospun niobium-doped tin oxide supported Pt cathode.

    Science.gov (United States)

    Savych, Iuliia; Subianto, Surya; Nabil, Yannick; Cavaliere, Sara; Jones, Deborah; Rozière, Jacques

    2015-07-14

    Novel platinum-catalysed, corrosion-resistant, loose-tube-structured electrocatalysts for proton exchange membrane fuel cells have been obtained using single-needle electrospinning associated with a microwave-assisted polyol method. Monodisperse platinum particles supported on Nb-SnO2 demonstrated higher electrochemical stability than conventional Pt/C electrodes during ex situ potential cycling and comparable activity in the oxygen reduction reaction. In situ fuel cell operation under accelerated stress test conditions of a membrane electrode assembly elaborated using a Pt/C anode and Pt/Nb-SnO2 cathode confirmed that the voltage loss is significantly lower for the novel cathode than for an MEA prepared using conventional Pt/C supported electrocatalysts. Furthermore, the Nb-SnO2 stabilised the supported platinum nanoparticles against dissolution, migration and reprecipitation in the membrane. Pt/Nb-SnO2 loose-tubes constitute a mitigation strategy for two known degradation mechanisms in PEMFC: corrosion of the carbon support at the cathode, and dissolution of Pt at high cell voltages.

  16. Development of nanobiomarkers for use in sickle cell anemia; Desenvolvimento de nanomarcadores para serem utilizados na marcacao de hemoglobinas S (anemia falciforme)

    Energy Technology Data Exchange (ETDEWEB)

    Santos, Elen Goncalves dos

    2009-07-01

    Luminescent materials, such as the rare earth's complex, can be used as markers in cytology and immunology, being also used as luminescent bio markers, once the development of these nano materials create new possibilities to many fields, particularly in diagnostic medicine. Besides, it establishes one kind of fluorescent probes, for which there are no equivalent organic molecules. Due to its potential in market's application, the objective of this work was to develop luminescent materials, allowing the use of these super molecules of lanthanides as markers for the detection of Sickle Cell Disease (HbS). Six luminescent markers were developed and marked on rare's earth base. The main methodology used for the detection of HbS was fluoroimmunoassay, which is already used in investigation of enzymes, antibodies, cells, hormones, and so on. During this work, absorption's spectrum in the infrared by Fourier's Transform (FTIR) was also used to detect the HbS. The studied methods were applied for the diagnosis of this disease, which has genetic origin, very typical of the hemoglobin-pathology group and considered to be a public health problem in Brazil (ANVISA). When early diagnosed, Sickle Cell Disease (SCD) has a significant decrease in morbidity and mortality. Comparing the obtained results to the already known methodologies, it was possible to conclude that they are viable methods to detect HbS. Besides, when totally developed, these methods will contribute to the production of Sickle Cell Anemia's diagnostic, and they will have impact in Sao Paulo state's public measures, as well as in Brazil's ones. (author)

  17. Nanostructure-based proton exchange membrane for fuel cell applications at high temperature.

    Science.gov (United States)

    Li, Junsheng; Wang, Zhengbang; Li, Junrui; Pan, Mu; Tang, Haolin

    2014-02-01

    As a clean and highly efficient energy source, the proton exchange membrane fuel cell (PEMFC) has been considered an ideal alternative to traditional fossil energy sources. Great efforts have been devoted to realizing the commercialization of the PEMFC in the past decade. To eliminate some technical problems that are associated with the low-temperature operation (such as catalyst poisoning and poor water management), PEMFCs are usually operated at elevated temperatures (e.g., > 100 degrees C). However, traditional proton exchange membrane (PEM) shows poor performance at elevated temperature. To achieve a high-performance PEM for high temperature fuel cell applications, novel PEMs, which are based on nanostructures, have been developed recently. In this review, we discuss and summarize the methods for fabricating the nanostructure-based PEMs for PEMFC operated at elevated temperatures and the high temperature performance of these PEMs. We also give an outlook on the rational design and development of the nanostructure-based PEMs.

  18. U.S. DOE Progress Towards Developing Low-Cost, High Performance, Durable Polymer Electrolyte Membranes for Fuel Cell Applications.

    Science.gov (United States)

    Houchins, Cassidy; Kleen, Greg J; Spendelow, Jacob S; Kopasz, John; Peterson, David; Garland, Nancy L; Ho, Donna Lee; Marcinkoski, Jason; Martin, Kathi Epping; Tyler, Reginald; Papageorgopoulos, Dimitrios C

    2012-12-18

    Low cost, durable, and selective membranes with high ionic conductivity are a priority need for wide-spread adoption of polymer electrolyte membrane fuel cells (PEMFCs) and direct methanol fuel cells (DMFCs). Electrolyte membranes are a major cost component of PEMFC stacks at low production volumes. PEMFC membranes also impose limitations on fuel cell system operating conditions that add system complexity and cost. Reactant gas and fuel permeation through the membrane leads to decreased fuel cell performance, loss of efficiency, and reduced durability in both PEMFCs and DMFCs. To address these challenges, the U.S. Department of Energy (DOE) Fuel Cell Technologies Program, in the Office of Energy Efficiency and Renewable Energy, supports research and development aimed at improving ion exchange membranes for fuel cells. For PEMFCs, efforts are primarily focused on developing materials for higher temperature operation (up to 120 °C) in automotive applications. For DMFCs, efforts are focused on developing membranes with reduced methanol permeability. In this paper, the recently revised DOE membrane targets, strategies, and highlights of DOE-funded projects to develop new, inexpensive membranes that have good performance in hot and dry conditions (PEMFC) and that reduce methanol crossover (DMFC) will be discussed.

  19. U.S. DOE Progress Towards Developing Low-Cost, High Performance, Durable Polymer Electrolyte Membranes for Fuel Cell Applications

    Science.gov (United States)

    Houchins, Cassidy; Kleen, Greg J.; Spendelow, Jacob S.; Kopasz, John; Peterson, David; Garland, Nancy L.; Ho, Donna Lee; Marcinkoski, Jason; Martin, Kathi Epping; Tyler, Reginald; Papageorgopoulos, Dimitrios C.

    2012-01-01

    Low cost, durable, and selective membranes with high ionic conductivity are a priority need for wide-spread adoption of polymer electrolyte membrane fuel cells (PEMFCs) and direct methanol fuel cells (DMFCs). Electrolyte membranes are a major cost component of PEMFC stacks at low production volumes. PEMFC membranes also impose limitations on fuel cell system operating conditions that add system complexity and cost. Reactant gas and fuel permeation through the membrane leads to decreased fuel cell performance, loss of efficiency, and reduced durability in both PEMFCs and DMFCs. To address these challenges, the U.S. Department of Energy (DOE) Fuel Cell Technologies Program, in the Office of Energy Efficiency and Renewable Energy, supports research and development aimed at improving ion exchange membranes for fuel cells. For PEMFCs, efforts are primarily focused on developing materials for higher temperature operation (up to 120 °C) in automotive applications. For DMFCs, efforts are focused on developing membranes with reduced methanol permeability. In this paper, the recently revised DOE membrane targets, strategies, and highlights of DOE-funded projects to develop new, inexpensive membranes that have good performance in hot and dry conditions (PEMFC) and that reduce methanol crossover (DMFC) will be discussed. PMID:24958432

  20. Promessa e desafios do desenvolvimento

    OpenAIRE

    Gereffi,Gary

    2007-01-01

    A economia global tem mudado rapidamente. China, Índia e México representam casos particularmente interessantes por seus distintos modelos de desenvolvimento. O processo de consolidação global ampliou-se na década passada na esteira do rápido crescimento da China nos setores de manufatura para exportação e da entrada em cena da Índia na exportação de serviços no ramo da tecnologia de informação. A indústria do vestuário também ilustra tal tendência à consolidação, dadas as mudanças na regulaç...

  1. Development of perovskite cathodes for solid oxide fuel cells (SOFC); Desenvolvimento de catodos de perovskitas para celula a combustivel solido de eletrolito solido (SOFC)

    Energy Technology Data Exchange (ETDEWEB)

    Perez, J. [UNESP, Araraquara, SP (Brazil). Inst. de Quimica], e-mail: joelma@iq.unesp.br; Pereira, J.T.; Saeki, M.J. [UNESP, Bauru, SP (Brazil). Faculdade de Ciencias

    2006-07-01

    Solid Oxide Fuel Cells (SOFC) are energy conversion systems of great interest for industrial applications because they present a high efficiency for energy generation and several advantages for the environment. In this work, perovskite type oxides La{sub 085}Sr{sub 0,15}MnO{sub 3}, La{sub 0,7} Sr{sub 0,3}MnO{sub 3}, La{sub 0,6}Sr{sub 0,4}MnO{sub 3}, La{sub 0,85}Sr{sub 0,15}CoO{sub 3}, La{sub 0,7}Sr{sub 0,3}CoO{sub 3}, La{sub 0,6}Sr{sub 0,4}CoO{sub 3}, La{sub 0.6}Sr{sub 0,4}Fe{sub 0,8}Co{sub 0,2}O{sub 3} e La{sub 0.6}Sr{sub 0,4}Fe{sub 0,4}Co{sub 0,6}O{sub 3} were prepared by a polymeric method with the purpose of using them as cathodes in SOFCs. The electrochemical cell was mounted utilizing YSZ (ZrO{sub 2} - 8 mol%Y{sub 2}O{sub 3}) disks as electrolyte, where a paste containing Pt was calcined onto one face while the other one was covered with the oxide materials synthesized ('screen printing'). The oxide materials prepared were characterized by X-ray diffraction, transmission electronic microscopy and thermogravimetry. The oxygen reduction reaction was studied by taking polarization curves in oxygen and/or air (800 deg C a 950 deg C). The best performance was obtained for 15 {mu}m thickness electrodes La{sub 0.6}Sr{sub 0,4}MnO{sub 3} and La{sub 0.6}Sr{sub 0,4}MnO{sub 3} with addition of dispersed Pt. (author)

  2. Development and scale-up of the production process of NovoCell fuel cells; Desenvolvimento e 'scale-up' do processo de producao de celulas a combustivel NovoCell

    Energy Technology Data Exchange (ETDEWEB)

    Azevedo, Dayse Caldas de; Souza, Adler de; Ferreira, Valdemar Stelita [NovoCell Sistemas de Energia S.A., Santa Barbara D' Oeste, SP (Brazil)]. E-mail: dayse.azevedo@novocell.ind.br

    2008-07-01

    Fuel cells present the potentiality to substitute the engines of internal combustion in vehicles and to supply energy for stationary use. This potentiality, however, not yet reflected in its introduction in the market with regular lines of production, because of its high cost and lack of criteria that demonstrate its reliability and durability. These subjects are the main goals of the programs of development of fuel cells worldwide. NovoCell is a Brazilian company whose objective is to develop and to produce hydrogen/air fuel cells for stationary generation. All the project is guided by the use of technologies/processes and materials that allow production in large scale and to a competitive cost, giving support to a continuous program of innovation and development of the product. In this work the technological solutions developed by the company are presented. (author)

  3. Effect of different surface treatments on the stability of stainless steels for use as bipolar plates in low and high temperature proton exchange membrane fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Richards, J.; Schmidt, K. [Fraunhofer-Institut fuer Chemische Technologie (ICT), Wolfsburg (Germany); Tuebke, J.; Cremers, C. [Fraunhofer-Institut fuer Chemische Technologie (ICT), Pfinztal (Germany)

    2010-07-01

    The stability of different stainless steels against corrosion under simulated low and high temperature proton exchange membrane fuel cell (PEMFC) operating conditions was studied. These investigations showed a moderate corrosion resistance for a couple of steels under LT-PEMFC conditions. However, for the HT-PEMFC conditions all specimens except one exhibit visible corrosion traces. With regards to their corrosion resistance after different surface treatments results show a minor improvement in corrosion resistance after the electro polishing process for most of the tested stainless steel samples. (orig.)

  4. Harvesting of PEM fuel cell heat energy for a thermal engine in an underwater glider

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Shuxin; Xie, Chungang; Wang, Yanhui; Zhang, Lianhong; Jie, Weiping [School of Mechanical Engineering, Tianjin University, Tianjin 300072 (China); Hu, S. Jack [Department of Mechanical Engineering, The University of Michigan, Ann Arbor, MI 48109-2125 (United States)

    2007-06-20

    The heat generated by a proton exchange membrane fuel cell (PEMFC) is generally removed from the cell by a cooling system. Combining heat energy and electricity in a PEMFC is highly desirable to achieve higher fuel efficiency. This paper describes the design of a new power system that combines the heat energy and electricity in a miniature PEMFC to improve the overall power efficiency in an underwater glider. The system makes use of the available heat energy for navigational power of the underwater glider while the electricity generated by the miniature PEMFC is used for the glider's sensors and control system. Experimental results show that the performance of the thermal engine can be obviously improved due to the high quality heat from the PEMFC compared with the ocean environmental thermal energy. Moreover, the overall fuel efficiency can be increased from 17 to 25% at different electric power levels by harvesting the PEMFC heat energy for an integrated fuel cell and thermal engine system in the underwater glider. (author)

  5. DESENVOLVIMENTO DE FOLÍCULOS PRÉ-ANTRAIS BOVINOS IN VITRO EM MONOCAMADA DE CÉLULAS OVARIANAS IN VITRO DEVELOPMENT OF BOVINE PREANTRAL FOLLICLES IN MONOLAYER OF OVARIAN CELLS

    Directory of Open Access Journals (Sweden)

    Luís Fabiano Santos da Costa

    2001-04-01

    Full Text Available O presente trabalho teve como objetivos determinar a influência de células ovarianas no desenvolvimento in vitro de folículos pré-antrais, avaliar a viabilidade das células ovarianas em monocamada e a influência do soro na manutenção de folículos pré-antrais in vitro. Folículos pré-antrais (FPs e células ovarianas foram isolados de ovários de fetos bovinos, com idade entre 6 e 8 meses de gestação, oriundos de matadouro. Células ovarianas em monocamada foram cultivadas em meio TCM-199, e a viabilidade celular, após o cultivo na presença ou ausência de FSH, foi determinada com o corante vital azul de tripan. FPs foram distribuidos em quatro tratamentos e cultivados em TCM-199 modificado, contendo soro de novilho castrado (SNC, SNC em monocamada de células ovarianas (MCO, MCO com FSH ou meio definido com álcool polivinílico (PVA como macromolécula. A viabilidade celular não foi afetada em conseqüência da presença ou ausência de FSH. No entanto, houve um incremento significativo no tamanho dos FPs cultivados na presença de SNC, MCO e FSH (PThe aim of the present work was to determine the influence of ovarian cells in the in vitro development of preantral follicles (PF. The viability of monolayer ovarian cells and the effect of the serum in the survive of in vitro PF was also investigated. Ovarian cells and PF were isolated from ovaries of bovine fetus between 6 and 8 months of pregnancy, obtained in a slaughterhouse. Monolayer of ovarian cells were cultured in a modified TCM-199 in the presence and absence of FSH and its viability after incubation was determined with Trypan Blue. PFs were divided in four different treatments, cultured in modified TCM-199, containing serum of castrated steer (SCS, SCS in monolayer of ovarian cells (MOC, MOC with FSH or a defined medium with polyvinyl alcohol (PVA as macromolecule. The cellular viability was not affected by the presence or absence of FSH. However, PFs had a significant

  6. Development of Novel PEM Membrane and Multiphase CD Modeling of PEM Fuel Cell

    Energy Technology Data Exchange (ETDEWEB)

    K. J. Berry; Susanta Das

    2009-12-30

    To understand heat and water management phenomena better within an operational proton exchange membrane fuel cell's (PEMFC) conditions, a three-dimensional, two-phase computational fluid dynamic (CFD) flow model has been developed and simulated for a complete PEMFC. Both liquid and gas phases are considered in the model by taking into account the gas flow, diffusion, charge transfer, change of phase, electro-osmosis, and electrochemical reactions to understand the overall dynamic behaviors of species within an operating PEMFC. The CFD model is solved numerically under different parametric conditions in terms of water management issues in order to improve cell performance. The results obtained from the CFD two-phase flow model simulations show improvement in cell performance as well as water management under PEMFCs operational conditions as compared to the results of a single phase flow model available in the literature. The quantitative information obtained from the two-phase model simulation results helped to develop a CFD control algorithm for low temperature PEM fuel cell stacks which opens up a route in designing improvement of PEMFC for better operational efficiency and performance. To understand heat and water management phenomena better within an operational proton exchange membrane fuel cell's (PEMFC) conditions, a three-dimensional, two-phase computational fluid dynamic (CFD) flow model has been developed and simulated for a complete PEMFC. Both liquid and gas phases are considered in the model by taking into account the gas flow, diffusion, charge transfer, change of phase, electro-osmosis, and electrochemical reactions to understand the overall dynamic behaviors of species within an operating PEMFC. The CFD model is solved numerically under different parametric conditions in terms of water management issues in order to improve cell performance. The results obtained from the CFD two-phase flow model simulations show improvement in cell

  7. Formation of Platinum Catalyst on Carbon Black Using an In‐Liquid Plasma Method for Fuel Cells

    Directory of Open Access Journals (Sweden)

    Yoshiyuki Show

    2017-01-01

    Full Text Available Platinum (Pt catalyst was formed on the surface of carbon black using an in‐liquid plasma method. The formed Pt catalyst showed the average particle size of 4.1 nm. This Pt catalyst was applied to a polymer electrolyte membrane fuel cell (PEMFC. The PEMFC showed an open voltage of 0.85 V and a maximum output power density of 216 mW/cm2.

  8. Evaluation and characterization of ceramic membranes based on Pdms/SiC containing phosphotungstic acid as electrolytes for PEM-FC

    International Nuclear Information System (INIS)

    Lima, Marcelo de Oliveira; Guimaraes, Danilo Hansen; Boaventura Filho, Jaime Soares; Jose, Nadia Mamede; Barbosa, Diego Augusto Batista; Paschoal, Carlos William de Araujo; Almeida, Rafael Mendonca; Tanaka, Auro Atsushi

    2009-01-01

    This work presents the development of membranes with potential use in Proton Exchange Fuel Cells (PEM-FC), consisting of hybrid materials based on poly(dimethylsiloxane), crosslinked with tetraethyl orthosilicate (TEOS), and reinforced with silicon carbide and phosphotungstic acid. The membrane series PDMS/TEOS/SiC/PWA were prepared by the reaction of PDMS and TEOS, 70/30% proportions in mass, catalyzed by dibutyltin dilaurate. SiC was incorporated in a 25% proportion, and PWA in varied proportions (5, 10, 15 and 20%), by weight. The membranes were characterized by Thermo-Gravimetric Analysis (TGA), X-ray Diffraction, Scanning Electron Microscopy and impedance spectroscopy. SiC and PWA addition to the membrane increased both structure organization and material crystallinity. The insertion of PWA provided an increase in the conductivity. However, maximum conductivity was obtained with concentration levels above 10%. The insertion of SiC associated with the PWA did not influence the conductivity for concentrations between 10 and 20%. (author)

  9. Enhancement of cell characteristics via baffle blocks in a proton ...

    Indian Academy of Sciences (India)

    Fuel cells are one type of device to produce green energy from fossil fuels in future applications. However, there are ... cell performance of a proton exchange membrane fuel cell (PEMFC) with a tapered flow channel design. ... oxygen consumption and liquid water production, so the cell performance is strongly dependent.

  10. Complicações neurológicas em anemia falciforme: avaliação neuropsicológica do desenvolvimento com o NEPSY Neurological complications in sickle cell anemia: a developmental neuropsychological assessment using NEPSY

    Directory of Open Access Journals (Sweden)

    Samantha Nunest

    2010-01-01

    Full Text Available Estudo de caso de duas crianças portadoras de anemia falciforme, com complicações neurológicas. Utilizou-se uma ampla bateria neuropsicológica - NEPSY. Uma criança apresentou acidente vascular cerebral com paresia de hemicorpo esquerdo, e a outra, ataque isquêmico transitório. As avaliações neuropsicológicas demonstraram que havia extenso prejuízo cognitivo no primeiro caso, em contraste com comprometimento leve no segundo. Baixas pontuações nas funções de atenção visual, memória operacional, linguagem, flexibilidade cognitiva, habilidades sensório-motora, visoespacial e viso-construtiva. Rebaixamento intelectual e no desempenho acadêmico foram encontrados no paciente que sofreu o acidente isquêmico. A criança que foi acometida por ataque isquêmico transitório apresentou dispraxia motora e oromotora, diminuição da atenção visual e memória verbal. Estes achados corroboram com os dados encontrados na literatura e reforçam a relevância de conhecer a tipologia destas alterações para intervir precocemente na deficiência cognitiva, minimizando as repercussões no desenvolvimento cognitivo, acadêmico e psicossocial.This is a case study of two children with sickle cell anemia and neurological complications. An extensive series of neuropsychological tests - NEPSY was used in the evaluation of the children. One child had suffered an ischemic stroke with left hemiparesis and the other, transient ischemic attack. The neuropsychological assessment showed extensive cognitive damage in the first case, in contrast to mild impairment in the second. Low scores were found for tasks of visual attention, operational memory, language, cognitive flexibility and for sensory-motor, visuospatial and visuoconstructive skills. Low intellectual and academic performance was found in the patient who suffered ischemic stroke. The child who suffered transient ischemic attack showed motor and oromotor dyspraxia, and decreased visual attention

  11. Self: um conceito em desenvolvimento

    Directory of Open Access Journals (Sweden)

    Lídia Suzana Rocha de Macedo

    2012-08-01

    Full Text Available Diversas definições de self coexistem nas teorias e práticas psicológicas. Essa variedade é resultante de bases epistemológicas a partir das quais se adotam estratégias diferentes para abordar e demarcar os limites do objeto em questão e descrevê-lo. Este estudo teve como objetivo oferecer uma revisão dos conceitos de self e uma reflexão sobre como esse conceito se articula nas diferentes abordagens teóricas da psicologia. Destaca-se que dilemas centrais à psicologia do desenvolvimento atravessam o conceito de self. Por essa razão, apresenta-se a tese de que, ao analisar cada definição de self, deve-se buscar responder como cada teoria colocou-se diante das dicotomias estabilidade versus transformação, específico versus universal e mundo interno versus mundo externo.

  12. HIGH TEMPERATURE POLYMER FUEL CELLS

    DEFF Research Database (Denmark)

    Jensen, Jens Oluf; Qingfeng, Li; He, Ronghuan

    2003-01-01

    This paper will report recent results from our group on polymer fuel cells (PEMFC) based on the temperature resistant polymer polybenzimidazole (PBI), which allow working temperatures up to 200°C. The membrane has a water drag number near zero and need no water management at all. The high working...

  13. Three-dimensional numerical study on cell performance and transport phenomena of PEM fuel cells with conventional flow fields

    Energy Technology Data Exchange (ETDEWEB)

    Jang, Jer-Huan [Department of Mechanical Engineering, Northern Taiwan Institute of Science and Technology, Beitou, Taipei 11202 (China); Yan, Wei-Mon; Li, Hung-Yi; Tsai, Wei-Che [Department of Mechatronic Engineering, Huafan University, Shih-Ting, Taipei 22305 (China)

    2008-01-15

    In this paper, a three-dimensional numerical model of the proton exchange membrane fuel cells (PEMFCs) with conventional flow field designs (parallel flow field, Z-type flow field, and serpentine flow field) has been established to investigate the performance and transport phenomena in the PEMFCs. The influences of the flow field designs on the fuel utilization, the water removal, and the cell performance of the PEMFC are studied. The distributions of velocity, oxygen mass fraction, current density, liquid water, and pressure with the convention flow fields are presented. For the conventional flow fields, the cell performance can be enhanced by adding the corner number, increasing the flow channel length, and decreasing the flow channel number. The cell performance of the serpentine flow field is the best, followed by the Z-type flow field and then the parallel flow field. (author)

  14. A teoria do “desenvolvimento fragmentador”

    Directory of Open Access Journals (Sweden)

    Fred Scholz

    2010-04-01

    Full Text Available O pensamento desenvolvimentista do passado era dominado pela ideia de que o subdesenvolvimento do Terceiro Mundo poderia ser superado mediante ajuda técnica, financeira e pessoal dos países do Norte. A meta era alcançar o nível de desenvolvimento dos países ocidentais industrializados por meio de um desenvolvimento retardatário. Na base dessa ideia estava, por um lado, o consenso de valores ocidental-humanitários, que, o mais tardar desde a época do Esclarecimento, determinou o pensar e o devir social. Por outro lado, a ideia baseou-se na responsabilidade histórica (surgida das condições da Guerra Fria, aceita política e socialmente do "Ocidente" para com os chamados países em desenvolvimento, na sua maioria ex-colônias. Argumenta-se, neste artigo, que a ideia de um desenvolvimento retardatário deve, na era da globalização, ser substituída pelo fato de um desenvolvimento fragmentador.

  15. Nutrição e desenvolvimento

    Directory of Open Access Journals (Sweden)

    Arruda Ilma K. G. de

    1994-01-01

    Full Text Available As discussões sobre desenvolvimento e nutrição freqüentemente se realizam sob um duplo enfoque: aqueles que consideram o estado nutricional como reflexo do desenvolvimento, e os que admitem que a nutrição influencia fortemente no nível e ritmo desse desenvolvimento. Os autores focalizam o tema visualizando a nutrição como um fator decisivo para um bom desenvolvimento social e econômico, particularizando o fato de que as intervenções nutricionais podem contribuir para melhorias significativas nos resultados escolares, na produtividade do trabalho e na resistência às infecções. Assim, os reflexos da desnutrição na economia seriam evidentes: quer pelas limitações na expectativa de renda, quer pelo aumento dos custos dos compromissos que a população assume para proteger-se, quer pelos avultados custos ocultos de origem social - absenteísmo, acidentes do trabalho e rotatividade de pessoal. Em face dos propósitos de modernização e competitividade da economia, é inquestionável a necessidade da nutrição figurar bem alto na lista de prioridades nacionais. Com isso, promover-se-ia o desenvolvimento dos recursos humanos e a preservação desse capital, que é o ideário de uma economia socialmente responsável.

  16. Transient response of a proton exchange membrane fuel cell

    Science.gov (United States)

    Weydahl, Helge; Møller-Holst, Steffen; Hagen, Georg; Børresen, Børre

    The transient response of a proton exchange membrane fuel cell (PEMFC) supplied with pure hydrogen and oxygen was investigated by load step measurements assisted by electrochemical impedance spectroscopy and chronoamperometry. Using an in-house designed resistance board, the uncontrolled response in both cell voltage and current upon step changes in a resistive load was observed. The PEMFC was found to respond quickly and reproducibly to load changes. The transient PEMFC response was limited by a cathodic charge transfer process with a potential-dependent response time. For load steps to high-current densitities, a second transient process with a constant response time was observed. This transient was offset from the charge transfer transient by a temporarily stable plateau. Results from chronoamperometry indicated that the second transient could be related to a diffusion process. Transient paths were plotted in the V- i diagram, matching a predicted pattern with overshooting cell voltage and current during a load step.

  17. Fuel Exhaling Fuel Cell.

    Science.gov (United States)

    Manzoor Bhat, Zahid; Thimmappa, Ravikumar; Devendrachari, Mruthyunjayachari Chattanahalli; Kottaichamy, Alagar Raja; Shafi, Shahid Pottachola; Varhade, Swapnil; Gautam, Manu; Thotiyl, Musthafa Ottakam

    2018-01-18

    State-of-the-art proton exchange membrane fuel cells (PEMFCs) anodically inhale H 2 fuel and cathodically expel water molecules. We show an unprecedented fuel cell concept exhibiting cathodic fuel exhalation capability of anodically inhaled fuel, driven by the neutralization energy on decoupling the direct acid-base chemistry. The fuel exhaling fuel cell delivered a peak power density of 70 mW/cm 2 at a peak current density of 160 mA/cm 2 with a cathodic H 2 output of ∼80 mL in 1 h. We illustrate that the energy benefits from the same fuel stream can at least be doubled by directing it through proposed neutralization electrochemical cell prior to PEMFC in a tandem configuration.

  18. Novel Blend Membranes Based on Acid-Base Interactions for Fuel Cells

    Directory of Open Access Journals (Sweden)

    Yongzhu Fu

    2012-10-01

    Full Text Available Fuel cells hold great promise for wide applications in portable, residential, and large-scale power supplies. For low temperature fuel cells, such as the proton exchange membrane fuel cells (PEMFCs and direct methanol fuel cells (DMFCs, proton-exchange membranes (PEMs are a key component determining the fuel cells performance. PEMs with high proton conductivity under anhydrous conditions can allow PEMFCs to be operated above 100 °C, enabling use of hydrogen fuels with high-CO contents and improving the electrocatalytic activity. PEMs with high proton conductivity and low methanol crossover are critical for lowering catalyst loadings at the cathode and improving the performance and long-term stability of DMFCs. This review provides a summary of a number of novel acid-base blend membranes consisting of an acidic polymer and a basic compound containing N-heterocycle groups, which are promising for PEMFCs and DMFCs.

  19. La-doped Al2O3 supported Au nanoparticles: highly active and selective catalysts for PROX under PEMFC operation conditions.

    Science.gov (United States)

    Lin, Qingquan; Qiao, Botao; Huang, Yanqiang; Li, Lin; Lin, Jian; Liu, Xiao Yan; Wang, Aiqin; Li, Wen-Cui; Zhang, Tao

    2014-03-14

    La-doped γ-Al2O3 supported Au catalysts show high activity and selectivity for the PROX reaction under PEMFC operation conditions. The superior performance is attributed to the formation of LaAlO3, which suppresses H2 oxidation and strengthens CO adsorption on Au sites, thereby improving competitive oxidation of CO at elevated temperature.

  20. Proton Exchange Membrane Fuel Cell Modelling Using Moving Least Squares Technique

    Directory of Open Access Journals (Sweden)

    Radu Tirnovan

    2009-07-01

    Full Text Available Proton exchange membrane fuel cell, with low polluting emissions, is a great alternative to replace the traditional electrical power sources for automotive applications or for small stationary consumers. This paper presents a numerical method, for the fuel cell modelling, based on moving least squares (MLS. Experimental data have been used for developing an approximated model of the PEMFC function of the current density, air inlet pressure and operating temperature of the fuel cell. The method can be applied for modelling others fuel cell sub-systems, such as the compressor. The method can be used for off-line or on-line identification of the PEMFC stack.

  1. CONHECIMENTO: UM FATOR DE DESENVOLVIMENTO ORGANIZACIONAL

    Directory of Open Access Journals (Sweden)

    Adilson dos Santos Morais

    2017-09-01

    Full Text Available Cada vez mais, criar conhecimento útil para atuar em uma posição de vantagem competitiva, orientado para o desenvolvimento organizacional e valorizando o capital humano tem-se demonstrato uma estratégia eficaz. O presente artigo busca apresentar a importância do conhecimento para o desenvolvimento das organizações em âmbito geral com destaque para as comunidades de prática. Esse conhecimento é derivado das interações desenvolvidas em processos de aprendizagem que ocorrem no ambiente organizacional. Para este, realizou-se um estudo teórico, descritivo, que tem como procedimento a pesquisa bibliográfica. Deste modo, apresenta como resultado deste trabalho a evidência de que existem poucos resultados divulgados sobre retorno financeiro e os benefícios dos investimentos realizados no capital intelectual humano pelas organizações. Porém, o conhecimento agrega valor à organização aumentando o valor do capital intelectual e as literaturas sobre o conhecimento e desenvolvimento organizacional consideram o capital intelectual o fator chave para a melhoria nos sistemas estratégicos. Destaca-se que esta contribuição poderá instigar cada vez mais a criação de conhecimento como fator de reconhecimento humano e de desenvolvimento das organizações.

  2. A Review on Cold Start of Proton Exchange Membrane Fuel Cells

    Directory of Open Access Journals (Sweden)

    Zhongmin Wan

    2014-05-01

    Full Text Available Successful and rapid startup of proton exchange membrane fuel cells (PEMFCs at subfreezing temperatures (also called cold start is of great importance for their commercialization in automotive and portable devices. In order to maintain good proton conductivity, the water content in the membrane must be kept at a certain level to ensure that the membrane remains fully hydrated. However, the water in the pores of the catalyst layer (CL, gas diffusion layer (GDL and the membrane may freeze once the cell temperature decreases below the freezing point (Tf. Thus, methods which could enable the fuel cell startup without or with slight performance degradation at subfreezing temperature need to be studied. This paper presents an extensive review on cold start of PEMFCs, including the state and phase changes of water in PEMFCs, impacts of water freezing on PEMFCs, numerical and experimental studies on PEMFCs, and cold start strategies. The impacts on each component of the fuel cell are discussed in detail. Related numerical and experimental work is also discussed. It should be mentioned that the cold start strategies, especially the enumerated patents, are of great reference value on the practical cold start process.

  3. Modeling and simulation of a 100 kWe HT-PEMFC subsystem integrated with an absorption chiller subsystem

    DEFF Research Database (Denmark)

    Arsalis, Alexandros

    2012-01-01

    electrical power output of 100 kWe. The heat exhausted to the absorption chiller subsystem is 107 kW and can satisfy a cooling duty of up to 128 or 64.5 kW for a LiBr-water double-effect system or a water-NH3 single-effect system, respectively. Finally, the projected total cost is comparable to conventional......A 100 kWe liquid-cooled HT-PEMFC subsystem is integrated with an absorption chiller subsystem to provide electricity and cooling. The system is designed, modeled and simulated to investigate the potential of this technology for future novel energy system applications. Liquid-cooling can provide...

  4. Dynamic characteristics of an automotive fuel cell system for transitory load changes

    DEFF Research Database (Denmark)

    Rabbani, Raja Abid; Rokni, Masoud

    2013-01-01

    A dynamic model of Polymer Electrolyte Membrane Fuel Cell (PEMFC) system is developed to investigate the behavior and transient response of a fuel cell system for automotive applications. Fuel cell dynamics are subjected to reactant flows, heat management and water transportation inside the fuel...

  5. Dynamic Simulation of a Proton Exchange Membrane Fuel Cell System For Automotive Applications

    DEFF Research Database (Denmark)

    Rabbani, Raja Abid; Rokni, Masoud

    2012-01-01

    A dynamic model of the PEMFC system is developed to investigate the behaviour and transient response of the fuel cell system for automotive applications. The system accounts for the fuel cell stack with coolant, humidifier, heat exchangers and pumps. Governing equations for fuel cell and humidifier...

  6. Metallofullerenes as fuel cell electrocatalysts: a theoretical investigation of adsorbates on C59Pt.

    Science.gov (United States)

    Gabriel, Margaret A; Genovese, Luigi; Krosnicki, Guillaume; Lemaire, Olivier; Deutsch, Thierry; Franco, Alejandro A

    2010-08-28

    Nano-structured electrode degradation in state-of-the-art polymer electrolyte membrane fuel cells (PEMFCs) is one of the main shortcomings that limit the large-scale development and commercialization of this technology. During normal operating conditions of the fuel cell, the PEMFC lifetime tends to be limited by coarsening of the cathode's Pt-based catalyst and by corrosion of the cathode's carbon black support. Because of their chemical properties, metallofullerenes such as C(59)Pt may be more electrochemically stable than the Pt/C mixture. In this paper we investigate, by theoretical methods, the stability of oxygen reduction reaction (ORR) adsorbates on the metallofullerene C(59)Pt and evaluate its potential as a PEMFC fuel cell catalyst.

  7. Opioid system manipulation during testicular development: results on sperm production and sertoli cells population = Manipulação do sistema opioidérgico durante o desenvolvimento testicular: consequência sobre a produção espermática e a população de células de sertoli

    Directory of Open Access Journals (Sweden)

    Fernanda Mafra Cajú

    2011-04-01

    Full Text Available The Sertoli cell has fundamental importance to the development andmaintenance of spermatogenesis, as well as it has a directly proportional numerical relationship to sperm production. The proliferative period of this cell in rats occurs between 13 days pre-natal and 21 days pos-natal, when is established the final population in adult animals. The Leydig cell can modulate the Sertoli cell proliferation during fetal and neonatal periodƒn throughƒnƒnƒÒ-endorphin. The manipulation of opioidergic system can promote changes in parameters related to development of nervous, endocrine andreproductive systems. By the way, the main purpose of this present work was to compare the effects of the blockade of opioid receptor blocking in Sertoli cells using naltrexone (50 mg kg-1 during fetal and neonatal period in Wistar rats. According to the results, themanipulation of opioidergic system during pre-natal period reduced the total length of seminiferous tubule and Sertoli cell population in adult rats, but sperm production was normal because this cell has had a compensatory response for spermatozoids support capacity.As celulas de Sertoli tem fundamental importancia para o desenvolvimento e manutencao da espermatogenese, bem como possuem uma relacao numerica diretamente proporcional com a producao espermatica. O periodo proliferativo destas celulas em ratos ocorre entre 13 dias pre-natal e 21 dias pos-natal, resultando na definicao da populacao decelulas de Sertoli nos animais adultos. As celulas de Leydig podem modular a proliferacao das celulas de Sertoli durante o periodo fetal e neonatal por meio da ƒÒ-endorfina. A manipulacao do sistema opioidergico durante esta fase pode promover alteracoes em parametros relacionados com o desenvolvimento dos sistemas nervoso, endocrino ereprodutivo. Em virtude disto, o objetivo do presente trabalho foi comparar os efeitos do bloqueio de receptores opioides nas celulas de Sertoli, utilizando o naltrexone (50 mg kg

  8. Durable Catalysts for High Temperature Proton Exchange Membrane Fuel Cells

    DEFF Research Database (Denmark)

    significant attention in recent years because of its potential advantages such as high CO tolerance, easy cooling, better heat utilization and possible integration with fuel processing units. However, the high temperature obviously aggravates the carbon corrosion and catalyst degradation. Based on thermally......Durability of proton exchange membrane fuel cells (PEMFCs) is recognized as one of the most important issues to be addressed before the commercialization. The failure mechanisms are not well understood, however, degradation of carbon supported noble metal catalysts is identified as a major failure...... corrosion, in turn, triggers the agglomeration of platinum particles resulting in reduction of the active surface area and catalytic activity. This is a major mechanism of the catalyst degradation and a key challenge to the PEMFC long-term durability. High temperature PEMFC, on the other hand, has attached...

  9. Optimization of Fuel Cell System Operating Conditions for Fuel Cell Vehicles

    OpenAIRE

    Zhao, Hengbing; Burke, Andy

    2008-01-01

    Proton Exchange Membrane fuel cell (PEMFC) technology for use in fuel cell vehicles and other applications has been intensively developed in recent decades. Besides the fuel cell stack, air and fuel control and thermal and water management are major challenges in the development of the fuel cell for vehicle applications. The air supply system can have a major impact on overall system efficiency. In this paper a fuel cell system model for optimizing system operating conditions was developed wh...

  10. Ambiente sociomoral e desenvolvimento da autonomia

    OpenAIRE

    Jakeline Alencar Andrade

    2003-01-01

    Esta dissertação aborda as relações entre o ambiente sociomoral e o desenvolvimento da autonomia das crianças de uma Escola da comunidade do Município de Porto Alegre-RS. O objetivo é descrever o ambiente sociomoral de cada sala de aula, construído nas relações interindividuais entre professores e alunos, e analisar o desenvolvimento da autonomia das crianças através do estudo do juízo moral. A pesquisa teórica fundamenta-se em vários estudos e abordagens sobre a moralidade e, em especial, no...

  11. Desenvolvimento Symbian na plataforma serie 60

    OpenAIRE

    Iida, Renato Faria

    2006-01-01

    Com o rápido avanço da tecnologia dos terminais celulares e a integração de funções de handhelds aos celulares, criam-se novas possibilidades de aplicações móveis. Atualmente existem várias linhas de desenvolvimento. As três principais linguagens são: · Symbian C++ · Java 2 Micro Edition · BREW O foco desse trabalho é mostrar o ciclo de desenvolvimento do Symbian C++ aplicado para aplicações baseadas em localização. O primeiro passo é entender a origem e as características básicas da linguage...

  12. Desenvolvimento larval de Brycon hilarii (Characiformes, Characidae

    Directory of Open Access Journals (Sweden)

    Fernando G. de Oliveira

    2012-03-01

    Full Text Available O presente estudo caracterizou o desenvolvimento inicial de Brycon hilarii (Valenciennes, 1850 através de caracteres morfométricos e merísticos e analisou as relações entre as características morfométricas das larvas ao longo do desenvolvimento usando modelos de regressão linear, quadrática e linear por partes. O material foi obtido nas bacias dos rios Cuiabá e Manso, Mato Grosso, Brasil, entre março de 2000 e março de 2004. Os indivíduos foram identificados e separados de acordo com o grau de desenvolvimento da notocorda e, posteriormente, medidos e contados os caracteres morfométricos e merísticos, respectivamente. O comprimento padrão variou entre 3,25 e 26,00 mm. Inicialmente, as larvas apresentaram maior concentração de pigmentos dendríticos ao longo do intestino e, em flexão e pós-flexão, intensificaram-se no dorso do corpo. Uma mancha umeral e outra no pedúnculo caudal foram observadas no final do estágio de pós-flexão. O intestino apresentou-se longo, o focinho curto, o órgão adesivo presente em larval vitelino e pré-flexão e a boca terminal por todo o desenvolvimento. O número total de miômeros variou de 41 a 50 (23 a 30 pré e 16 a 24 pós-anal. O número de raios das nadadeiras foi: dorsal 11; anal 30; peitoral 15 e ventral oito. A análise do crescimento indicou maior metamorfose no estágio de flexão.

  13. Construction and evaluation of a proton exchange fuel cell

    International Nuclear Information System (INIS)

    Gutierrez, Omar; Monsalve, Carlos; Trujillo, Gonzalo; Hoyos, Bibian; Sanchez, Carlos; Gonzalez, Javier

    2005-01-01

    One design of a hydrogen proton exchange membrane fuel cell (PEMFC) is proposed. Porous carbon supported platinum electrodes were manufactured by impregnation, reduction and hot-press methods; noble metal loading of 0.4 mg/cm 2 was achieved. The conditions to obtain the porous support were: composition of 15 % Teflon and 85 % carbon, pressure of 100 Kgf/cm 2 , temperature of 300 Celsius degrade and 20 minutes of hot-pressing. The pattern of gas flow distribution was made possible by machined interdigitated channels into conductor graphite plates. Several tests were run varying the load resistance to obtain the polarization curves. Comparison with a commercial PEMFC is also made

  14. ECO-92: MEIO AMBIENTE E DESENVOLVIMENTO

    Directory of Open Access Journals (Sweden)

    . Editorial

    1992-01-01

    Full Text Available A cidade do Rio de Janeiro transformou-se durante alguns dias em capital mundial da ecologia. Lá se debateu o problema — tão angustiante para a humanidade de hoje — de conciliar ecologia e desenvolvimento. Sena deturpar o objetivo deste fórum internacional se o reduzíssemos à defesa da ecologia em detrimento do desenvolvimento. De fato. os dois pólos não são necessariamente irreconciliáveis. embora até o presente o desenvolvimento tenha sido incentivado às custas da destruição e depredação da natureza. As consequências são patentes: morte lenta de rios e mares, poluição sonora e atmosférica das grandes cidades, urbanização caótica e desumana, desmatamento, extinção de milhares de espécies, alterações climáticas, uso desmesurado de defensivos agrícolas, empobrecimento gradativo de solos antes férteis etc.

  15. Numerical investigation of interfacial mass transport resistance and two-phase flow in PEM fuel cell air channels

    Science.gov (United States)

    Koz, Mustafa

    Proton exchange membrane fuel cells (PEMFCs) are efficient and environmentally friendly electrochemical engines. The performance of a PEMFC is adversely affected by oxygen (O2) concentration loss from the air flow channel to the cathode catalyst layer (CL). Oxygen transport resistance at the gas diffusion layer (GDL) and air channel interface is a non-negligible component of the O2 concentration loss. Simplified PEMFC performance models in the available literature incorporate the O2 resistance at the GDL-channel interface as an input parameter. However, this parameter has been taken as a constant so far in the available literature and does not reflect variable PEMFC operating conditions and the effect of two-phase flow in the channels. This study numerically calculates the O2 transport resistance at the GDL-air channel interface and expresses this resistance through the non-dimensional Sherwood number (Sh). Local Sh is investigated in an air channel with multiple droplets and films inside. These water features are represented as solid obstructions and only air flow is simulated. Local variations of Sh in the flow direction are obtained as a function of superficial air velocity, water feature size, and uniform spacing between water features. These variations are expressed with mathematical expressions for the PEMFC performance models to utilize and save computational resources. The resulting mathematical correlations for Sh can be utilized in PEMFC performance models. These models can predict cell performance more accurately with the help of the results of this work. Moreover, PEMFC performance models do not need to use a look-up table since the results were expressed through correlations. Performance models can be kept simplified although their predictions will become more realistic. Since two-phase flow in channels is experienced mostly at lower temperatures, performance optimization at low temperatures can be done easier.

  16. Investigation of heating and cooling in a stand-alone high temperature PEM fuel cell system

    International Nuclear Information System (INIS)

    Zhang, Caizhi; Yu, Tao; Yi, Jun; Liu, Zhitao; Raj, Kamal Abdul Rasheedj; Xia, Lingchao; Tu, Zhengkai; Chan, Siew Hwa

    2016-01-01

    Highlights: • Heating-up and cooling-down processes of HT-PEMFC are the mainly interested topics. • Dynamic behaviours, power and energy demand of the heating and cooling was studied. • Hybrid system based on LiFeYPO 4 battery for heating and cooling is built and tested. • The concept of combining different heating sources together is recommended. - Abstract: One key issue pertaining to the cold-start of High temperature PEM fuel cell (HT-PEMFC) is the requirement of high amount of thermal energy for heating up the stack to a temperature of 120 °C or above before it can generate electricity. Furthermore, cooling down the stack to a certain temperature (e.g. 50 °C) is necessary before stopping. In this study, the dynamic behaviours, power and energy demand of a 6 kW liquid cooled HT-PEMFC stack during heating-up, operation and cooling-down were investigated experimentally. The dynamic behaviours of fuel cell under heating-up and cooling-down processes are the mainly interested topics. Then a hybridisation of HT-PEMFC with Li-ion battery to demonstrate the synergistic effect on dynamic behaviour was conducted and validated for its feasibility. At last, the concept of combining different heating sources together is analysed to reduce the heating time of the HT-PEMFC as well.

  17. Influence of Silica/Sulfonated Polyether-Ether Ketone as Polymer Electrolyte Membrane for Hydrogen Fueled Proton Exchange Membrane Fuel Cells

    Directory of Open Access Journals (Sweden)

    Sri Handayani

    2011-12-01

    Full Text Available The operation of non-humidified condition of proton exchange membrane fuel cell (PEMFC using composite sPEEK-silica membrane is reported. Sulfonated membrane of PEEK is known as hydrocarbon polyelectrolyte membrane for PEMFC and direct methanol fuel cell (DMFC. The state of the art of fuel cells is based on the perluorosulfonic acid membrane (Nafion. Nafion has been the most used in both PEMFC and DMFC due to good performance although in low humidified condition showed poor current density. Here we reported the effect of silica in hydrocarbon sPEEK membrane that contributes for a better water management system inside the cell, and showed 0.16 W/cm2 of power density which is 78% higher than that of non-silica modified [Keywords: composite membrane, polyether-ether ketone, silica, proton exchange membrane fuel cell].

  18. Recent Progress on the Key Materials and Components for Proton Exchange Membrane Fuel Cells in Vehicle Applications

    Directory of Open Access Journals (Sweden)

    Cheng Wang

    2016-07-01

    Full Text Available Fuel cells are the most clean and efficient power source for vehicles. In particular, proton exchange membrane fuel cells (PEMFCs are the most promising candidate for automobile applications due to their rapid start-up and low-temperature operation. Through extensive global research efforts in the latest decade, the performance of PEMFCs, including energy efficiency, volumetric and mass power density, and low temperature startup ability, have achieved significant breakthroughs. In 2014, fuel cell powered vehicles were introduced into the market by several prominent vehicle companies. However, the low durability and high cost of PEMFC systems are still the main obstacles for large-scale industrialization of this technology. The key materials and components used in PEMFCs greatly affect their durability and cost. In this review, the technical progress of key materials and components for PEMFCs has been summarized and critically discussed, including topics such as the membrane, catalyst layer, gas diffusion layer, and bipolar plate. The development of high-durability processing technologies is also introduced. Finally, this review is concluded with personal perspectives on the future research directions of this area.

  19. Integration of autothermal diesel reformer for hydrogen production feeding a PEMFC; Integracion de reformador diesel con pilas de combustible tipo PEM

    Energy Technology Data Exchange (ETDEWEB)

    Rosa, F. I.; Briceno, Y. B.; Navarro, R. M.; Alvarez, C.; Bordons, C.

    2004-07-01

    This paper presents carried out actions to design and construct an autothermal diesel reformer for hydrogen production feeding a PEMFC.These activities have been performed by INTA, AICIA, CIDAUT and ICP-CSIC trough a collaborative effort 50% funded by INTA and by partners as in kind contributions as a function of developed tasks.The paper presents activities carried out to date: selection of a catalyst, simulation of the process, design and construction of a 5 kW autothermal diesel reformer. Reformer will be characterized during the second half of 2004 and, finally, will be installed for a proper operation together with a 5 kW PEMFC at the promises of INTA located in Centro de Experimentacion de Arenosillo at Huelva. (Author)

  20. Desenvolvimento econômico, desigualdade e saúde

    Directory of Open Access Journals (Sweden)

    Pedro Reginaldo Prata

    1994-09-01

    Full Text Available O autor se refere a dimensão socioeconômica, individual e coletiva do fenômeno saúde-doença. Refere-se também ao fato das populações estarem sobre a influência desigual de fatores de risco e de proteção à saúde. Discute as desigualdades no desenvolvimento e a relação entre desenvolvimento, riqueza, saúde e justiça social. Questiona as teorias de desenvolvimento econômico, diferenciando desenvolvimento de crescimento. Cunha os conceitos de armadilha do desenvolvimento e refugiados sociais. Define uma comunidade saudável. Propõe a necessidade de mudança no modelo de desenvolvimento. Baliza o papel e as limitações do setor saúde no que diz respeito a iniqüidade social.

  1. Desenvolvimento econômico, desigualdade e saúde

    Directory of Open Access Journals (Sweden)

    Prata Pedro Reginaldo

    1994-01-01

    Full Text Available O autor se refere a dimensão socioeconômica, individual e coletiva do fenômeno saúde-doença. Refere-se também ao fato das populações estarem sobre a influência desigual de fatores de risco e de proteção à saúde. Discute as desigualdades no desenvolvimento e a relação entre desenvolvimento, riqueza, saúde e justiça social. Questiona as teorias de desenvolvimento econômico, diferenciando desenvolvimento de crescimento. Cunha os conceitos de armadilha do desenvolvimento e refugiados sociais. Define uma comunidade saudável. Propõe a necessidade de mudança no modelo de desenvolvimento. Baliza o papel e as limitações do setor saúde no que diz respeito a iniqüidade social.

  2. Desenvolvimento motor e autoconceito de escolares com transtorno do desenvolvimento da coordenação

    OpenAIRE

    Beltrame, Thais Silva; Cardoso, Fernando Luiz; Alexandre, Juliano Maestri; Bernardi, Carla Simon

    2016-01-01

    Resumo Verificou-se a influência de um programa de intervenção motora no desenvolvimento motor e autoconceito de escolares com Transtorno do Desenvolvimento da Coordenação (TDC). Participaram do programa de intervenção de 16 semanas,12 crianças com idades de 10 anos (± 6 meses), divididas em dois grupos;sete escolares com indicativo TDC (GT) e cinco escolares com risco para TDC (GR). Utilizou-se a bateria motora MABC-2 (Henderson, Sugden, & Barnett, 2007) e a Escala de Auto-percepção para Cri...

  3. Analysis Of The Effect Of Flow Channel Width On The Performance Of PEMFC

    Directory of Open Access Journals (Sweden)

    Elif Eker

    2013-08-01

    Full Text Available In this work, it was analysed the effect of different channel width on performance of PEM fuel cell. Current density were measured on the single cells of parallel flow fields that has 25 cm² active layer, using three different kinds of channel width. The cell width and the channel height remain constant.The results show that increasing the channel width while the cell width remains constant decreases the current density.

  4. High temperature polymer electrolyte membrane fuel cells: Approaches, status, and perspectives

    DEFF Research Database (Denmark)

    This book is a comprehensive review of high-temperature polymer electrolyte membrane fuel cells (PEMFCs). PEMFCs are the preferred fuel cells for a variety of applications such as automobiles, cogeneration of heat and power units, emergency power and portable electronics. The first 5 chapters...... of the book describe rationalization and illustration of approaches to high temperature PEM systems. Chapters 6 - 13 are devoted to fabrication, optimization and characterization of phosphoric acid-doped polybenzimidazole membranes, the very first electrolyte system that has demonstrated the concept...... of and motivated extensive research activity in the field. The last 11 chapters summarize the state-of-the-art of technological development of high temperature-PEMFCs based on acid doped PBI membranes including catalysts, electrodes, MEAs, bipolar plates, modelling, stacking, diagnostics and applications....

  5. Further Improvement and System Integration of High Temperature Polymer Electrolyte Membrane Fuel Cells

    DEFF Research Database (Denmark)

    Li, Qingfeng; Jensen, Jens Oluf

    The new development in the field of polymer electrolyte membrane fuel cell (PEMFC) is high temperature PEMFC for operation above 100°C, which has been successfully demonstrated through the previous EC Joule III and the 5th framework programme. New challenges are encountered, bottlenecks for the new...... are to be developed and integrated with the stack. The key issue of the project is development and improvement of the temperature-resistant polymer membranes with respect to durability, conductivity, mechanical and other properties. For this purpose, basic polymers will be first synthesized and optimized. Different...... routes to functionalize the polymers will be explored to increate proton conductivity. By the development of advanced materials, demonstration of the high temperature PEMFC stack and integration of such a system, FURIM is expected to sufficiently promote the commercialisation of the fuel cell technology...

  6. Caracterização física, físico-química, enzimática e de parede celular em diferentes estádios de desenvolvimento da fruta de figueira Physical, chemico-physical, enzymatic and cell wall charazterization during the different development stages of the fig tree fruits

    Directory of Open Access Journals (Sweden)

    Carlos Antonio A. Gonçalves

    2006-03-01

    diferentes estádios de desenvolvimento dos frutos. Com a maturação dos frutos, houve redução dos principais componentes dos polissacarídeos pécticos (galactose, arabinose e ramnose, enquanto os componentes da fração hemicelulósica (xilose, glucose e manose tenderam a aumentar. A solubilização da celulose e queda nos teores de hemicelulose se deu a partir dos 60 dias, quando o fruto, já na maturidade fisiológica, inicia o processo de amaciamento, em função da solubilização de pectinas, pela maior atividade das enzimas pectinametilesterase e poligalacturonase.With the objective of evaluating the physical, physical-chemical, enzymic and cell wall characterization during the different developmental stages of the fig tree fruits under irrigation in Northern Minas Gerais, the present work was developed during the 2001/2002 cropping cycle in the Unidade de Produção Frutícola da Escola Agrotécnica Federal de Salinas (Fruit Growing Unit of the Federal Agrotechnical School of Salinas (Eafsal, town of Salinas. Plants of two years and a half after transplanting and with twelve well developed primary branches (pernadas = the first strong branches of a tree and 2.5x1.5 m spacing were utilized in this experiment. The design applied was completely randomized with two replicates and a total of 40 marked plants. The data collected were concerning 2001/2002 cropping cycle for the June-pruned plants. Evaluated during the different developmental stages of fig tree fruits activity of the enzimes, chemical composition, physical evaluate, neutral sugars and cell wall components. As polyphenoloxidase and peroxidase activity was decreasing, polygalacturonase activity increased throughout the development of the fruits. The fruits reached harvest point for industry and in natura consumption at 30 and 75 days from the differentiation of the buds in syconium, respectively. A significant increase took place in the contents of total soluble solids, total soluble and reducing sugars

  7. Membranas híbridas basadas en estireno-metacrilato-sílice y ácido fosfowolfrámico obtenidas por sol-gel para pilas de combustible de intercambio protónico (PEMFC

    Directory of Open Access Journals (Sweden)

    Mosa, J.

    2007-10-01

    Full Text Available Contrary to internal combustion engines, proton-exchange membrane fuel cells (PEMFC used in transportation operate with zero emissions of environmental pollutants. The increase of the operation temperature in PEMFC above 100°C is a great concern for the application of this type of cells in electric vehicles. Hybrid organic-inorganic membranes with nanosized interfaces can combine the main properties of their components to meet this objective. Styrene-methacrylate-silica membranes doped with phosphotungstic acid (PWA were prepared through acid catalyzed sol-gel process and free-radical copolymerization. Additionally, sulfonation processes of aromatic rings to produce attached SO3H groups were applied to increase the proton conductivity. The effect of sulfonation degree and PWA doping on the membrane properties such as chemical and thermal stability, water uptake, ion exchange capacity, and proton conductivity were investigated. The measurement of conductivity shows a general increase with rising temperatures and with the increasing of SO3H groups density, reaching a maximum value of 3.2 10-3 S/cm at 130ºC and 100%HR.

    Comparadas con los motores de combustión interna, las pilas de combustible de intercambio de protones (PEMFC son capaces de operar sin emisiones de agentes contaminantes. El aumento de la temperatura de operación de la pila de combustible por encima de 100ºC es uno de los grandes objetivos en este campo ya que facilitaría el desarrollo comercial de los vehículos eléctricos impulsados por pilas de combustible. Las membranas híbridas orgánico-inorgánicas nanoestructuradas combinan las propiedades necesarias para este tipo de aplicación. Se obtuvieron membranas híbridas dopadas con ácido fosfowolfrámico (PWA por copolimerización radicálica a partir de alquilalcóxidos y monómeros de estireno y metacrilato, y por reacción sol-gel vía catálisis ácida. La conductividad protónica se logra realizando un proceso

  8. Fuel cell catalyst degradation

    DEFF Research Database (Denmark)

    Arenz, Matthias; Zana, Alessandro

    2016-01-01

    Fuel cells are an important piece in our quest for a sustainable energy supply. Although there are several different types of fuel cells, the by far most popular is the proton exchange membrane fuel cell (PEMFC). Among its many favorable properties are a short start up time and a high power density...... increasing focus. Activity of the catalyst is important, but stability is essential. In the presented perspective paper, we review recent efforts to investigate fuel cell catalysts ex-situ in electrochemical half-cell measurements. Due to the amount of different studies, this review has no intention to give...

  9. Durability Issues and Status of PBI-Based Fuel Cells

    DEFF Research Database (Denmark)

    Jakobsen, Mark Tonny Dalsgaard; Jensen, Jens Oluf; Cleemann, Lars Nilausen

    2016-01-01

    This chapter briefly reviews durability and stability issues with key materials and components for HT-PEMFCs, including the polymer membrane, the doping acid, the electrocatalyst, the catalyst support and bipolar plates. Degradation mechanisms and their dependence on fuel cell operating condition...

  10. Optimum Performance of Direct Hydrogen Hybrid Fuel Cell Vehicles

    OpenAIRE

    Zhao, Hengbing; Burke, Andy

    2009-01-01

    Proton Exchange Membrane fuel cell (PEMFC) technology is one of the most attractive candidates for transportation applications due to its inherently high efficiency and high power density. However, the fuel cell system efficiency can suffer because of the need for forced air supply and water-cooling systems. Hence the operating strategy of the fuel cell system can have a significant impact on the fuel cell system efficiency and thus vehicle fuel economy. The key issues are how the fuel cell b...

  11. A semi-empirical voltage degradation model for a low-pressure proton exchange membrane fuel cell stack under bus city driving cycles

    Energy Technology Data Exchange (ETDEWEB)

    Lu, Languang; Ouyang, Minggao; Huang, Haiyan; Pei, Pucheng; Yang, Fuyuan [State Key Laboratory of Automotive Safety and Energy, Tsinghua University, Beijing 100084 (China)

    2007-01-10

    A voltage degradation model for the low-pressure proton exchange membrane fuel cell (PEMFC) stack used in a fuel cell bus is presented: (1) the oxygen concentration term was derived from the PEMFC output voltage equation, and the concept of oxygen concentration resistance coefficient was introduced; (2) a 5kW low-pressure PEMFC stack was used in this study. Two similar tests were carried out before and after the stack operating in the driving cycle for 640h. First, the ohmic losses under different temperatures were measured using the current interrupt method and formulized with linear fitting method. Then, the oxygen concentration term was studied by the experiments with different air stoichiometric ratios while keeping the other operating parameters unchanged. The oxygen concentration resistance coefficient was obtained from the difference of voltages for the PEMFC stack in different air stoichiometric ratios using the genetic optimization algorithm. Then, the activation loss was obtained based on the PEMFC output voltage, the ohmic loss, and the concentration loss. The degradation model of the stack was built finally by comparing the two test results; (3) the correlation of the model to the actual experimental data is good; (4) the overvoltage of the stack with aging was analyzed using this model. The analysis showed that the activation overvoltage dominated the stack loss with about 80% of the total losses, followed by the ohmic loss. The concentration loss almost does not change with aging in the driving cycle condition; (5) the comparison of the simulation with the actual data from the PEMFC bus running for 30,000km indicated that after 36,000km the rated power of the PEMFC bus must be reduced. (author)

  12. Analise funcional discriminativa em dislexia do desenvolvimento

    OpenAIRE

    Magda Solange Vanzo Pestun

    2001-01-01

    Resumo: Esta tese teve por objetivos avaliar e analisar através de provas neuropsicológicas, pedagógicas e exames complementares, crianças com possível diagnóstico de Dislexia do Desenvolvimento. Participaram como sujeitos 47 crianças, sendo 27 controles (sem dificuldades de aprendizagem) e 20 experimentais, com idade entre 8 e 13 anos, alunos de 23 série do 10grau de escola da rede pública da região de Campinas, SP. A coleta de dados se deu no HCIUNICAMP para os sujeitos do grupo experimenta...

  13. A brinquedoteca e o desenvolvimento infantil

    OpenAIRE

    Ramalho, Márcia Terezinha de Borja

    2000-01-01

    Dissertação (Mestrado) - Universidade Federal de Santa Catarina, Centro Tecnológico. O desenvolvimento infantil segundo Piaget e Vygotsky. O Brincar. O jogo. O Brinquedo. A Brincadeira. Brinquedos construídos com sucata. A cultura infantil. Pesquisa de Campo incluindo uma amostra de nove brinquedotecas em Florianópolis-Santa Catarina em Instituições de Educação Infantil , abrangendo a faixa etária de 0-6 anos. Atividades desenvolvidas nas brinquedotecas, estrutura, principais brinc...

  14. Desenvolvimento Textil. Malha artesanal e sustentabilidade

    OpenAIRE

    Cacho, Filipa Vieira

    2011-01-01

    Tese de Mestrado em Design de Moda Este projecto, de carácter experimental, visa o desenvolvimento de um novo têxtil que responda às necessidades e preocupações levantadas pelo estilo de vida actual. Ao mesmo tempo, procura inovar o design de malhas artesanal tradicional que tem vindo a viver um revivalismo dentro da moda contemporânea de vanguarda. Uma das maiores preocupações actuais da indústria têxtil, bem como de outras indústrias, é a sustentabilidade, o que se traduz no desenvolvime...

  15. Desenvolvimento aplicacional CRM em Modelo Cloud

    OpenAIRE

    Pinto, Joana Correia

    2017-01-01

    Trabalho de projeto de mestrado, Engenharia Informática (Sistemas de Informação) Universidade de Lisboa, Faculdade de Ciências, 2017 O presente relatório descreve o trabalho realizado no Projeto de Engenharia Informática na empresa Unipartner IT Services, que decorreu desde novembro de 2016. Este trabalho está inserido no âmbito do projeto “Desenvolvimento Aplicacional sobre Modelos Cloud”. Uma solução CRM tem como principais objetivos melhorar as relações entre as empresas e os seus clien...

  16. Desenvolvimento de um novo conceito de refrigerante

    OpenAIRE

    Ribeiro, Tânia Isabel Bragança

    2011-01-01

    Dissertação para obtenção de grau de mestre em Tecnologia e Segurança Alimentar – Qualidade Alimentar A indústria de refrigerantes e sumos é um subsector da indústria de bebidas não-alcoólicas, de grande impacte na economia e elevada competitividade. O desenvolvimento de novos produtos e a garantia de qualidade dos produtos são de extrema importância nesta indústria. Actualmente, o consumidor é bastante preocupado com a saúde, procurando produtos que possam não comprometer e/ou impulsionar...

  17. Portable power applications of fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Weston, M.; Matcham, J.

    2002-07-01

    This report describes the state-of-the-art of fuel cell technology for portable power applications. The study involved a comprehensive literature review. Proton exchange membrane fuel cells (PEMFCs) have attracted much more interest than either direct methanol fuel cells (DMFCs) or solid oxide fuel cells (SOFCs). However, issues relating to fuel choice and catalyst design remain with PEMFCs; DMFCs have excellent potential provided issues relating to the conducting membrane can be resolved but the current high temperature of operation and low power density currently makes SOFCs less applicable to portable applications. Available products are listed and the obstacles to market penetration are discussed. The main barriers are cost and the size/weight of fuel cells compared with batteries. Another key problem is the lack of a suitable fuel infrastructure.

  18. High temperature PEMFC and the possible utilization of the excess heat for fuel processing

    Energy Technology Data Exchange (ETDEWEB)

    Jensen, Jens Oluf; Li, Qingfeng; Pan, Chao; Vestboe, Andreas P.; Mortensen, Kasper; Nybo Petersen, Henrik; Lau Soerensen, Christian; Nedergaard Clausen, Thomas; Bjerrum, Niels J. [Department of Chemistry, Building 207, Technical University of Denmark, DK-2800 Lyngby (Denmark); Schramm, Jesper [Department of Mechanical Engineering, Building 404, Technical University of Denmark, DK-2800 Lyngby (Denmark)

    2007-07-15

    In this paper simple heat balances are calculated for systems with methanol and methane reformers in combination with a high temperature PEM fuel cell. In the methanol system at least 11.1% of the fuel energy can be saved by using the excess heat from the fuel cell for vaporization of water and methanol if the cell is operated at temperatures between 150 and 200 {sup circle} C. Similarly, in the methane system, 9.6% can be saved under equivalent conditions. Integration of a high temperature PEM fuel cell with a metal hydride system based on NaAlH{sub 4} is considered briefly with respect to desorption heat. Dead-end operation is studied, and stable performance is seen for 100 min at 150 {sup circle} C without purging. Finally, experiments are reported indicating that preheating of the air has no influence on the fuel cell performance at 150 or 200 {sup circle} C under moderate load. (author)

  19. Al2O3 Disk Supported Si3N4 Hydrogen Purification Membrane for Low Temperature Polymer Electrolyte Membrane Fuel Cells

    Directory of Open Access Journals (Sweden)

    Xiaoteng Liu

    2013-12-01

    Full Text Available Reformate gas, a commonly employed fuel for polymer electrolyte membrane fuel cells (PEMFCs, contains carbon monoxide, which poisons Pt-containing anodes in such devices. A novel, low-cost mesoporous Si3N4 selective gas separation material was tested as a hydrogen clean-up membrane to remove CO from simulated feed gas to single-cell PEMFC, employing Nafion as the polymer electrolyte membrane. Polarization and power density measurements and gas chromatography showed a clear effect of separating the CO from the gas mixture; the performance and durability of the fuel cell was thereby significantly improved.

  20. Desenvolvimento puberal em meninas tratadas de LLA

    Directory of Open Access Journals (Sweden)

    Monteiro I.M.M.

    1998-01-01

    Full Text Available OBJETIVO: Com o objetivo de avaliar o desenvolvimento puberal após o tratamento de leucemia linfóide aguda (LLA na infância, foi realizado um estudo retrospectivo, em meninas tratadas de janeiro de 1980 a janeiro de 1991, no Centro de Investigações Hematológicas "Dr. Domingos A. Boldrini", em Campinas-SP. CASUÍSTICA E MÉTODO: Foram selecionadas 42 meninas, tratadas antes da puberdade com quimioterapia sistêmica e intratecal e radioterapia cranial, utilizando doses de 18 ou 24 Grays (Gy. RESULTADOS: As idades médias da telarca, pubarca e menarca foram inferiores às do grupo-controle, embora com significância estatística apenas para a idade da telarca. Não houve diferenças entre os grupos tratados com 18 ou 24Gy. As meninas tratadas antes dos cinco anos de idade apresentaram idade média da menarca estatisticamente inferior àquelas tratadas após cinco anos e em relação ao grupo-controle. CONCLUSÃO: Os resultados mostraram que o desenvolvimento puberal em meninas tratadas de LLA na infância foi mais precoce que o de meninas saudáveis.

  1. Charles Darwin: um observador do desenvolvimento humano

    Directory of Open Access Journals (Sweden)

    Eloisa Helena Rubello Valler Celeri

    2010-12-01

    Full Text Available Os autores traduzem, pela primeira vez para o português, o artigo de Charles Darwin "A Biographical Sketch of an Infant", publicado no periódico Mind em julho de 1877. Utilizando anotações de observações do desenvolvimento de seus filhos, especialmente de seu filho mais velho William Erasmus (Doddy, Darwin descreve e estuda, a partir de seu enfoque naturalista, o filhote humano, narrando os primeiros indicativos comportamentais de emoções tais como raiva e medo, curiosidade e senso moral, o brincar e o prazer envolvido nesta atividade, a capacidade de imitação e os primeiros indícios daquilo que hoje conhecemos como "teoria da mente". Colocando-se questões sobre as capacidades do bebê, como eles aprendem e como se comunicam e levantando hipóteses sobre possíveis significados de certos comportamentos, questões ainda hoje fundamentais para o estudo do desenvolvimento humano, Darwin mostra-se também um pioneiro no estudo do bebê e da criança pequena, numa época na qual as capacidades dos bebês eram extremamente subestimadas e desconsideradas.

  2. Compact modeling of a telecom back-up unit powered by air-cooled proton exchange membrane fuel cell

    DEFF Research Database (Denmark)

    Gao, Xin; Kær, Søren Knudsen

    2018-01-01

    Applications of proton exchange membrane fuel cells (PEMFC’s) are expanding in portable, automotive and stationary markets. One promising application is the back-up power for telecommunication applications in remote areas where usually air-cooled PMEFC’s are used. An air-cooled PEMFC system is much...... simpler and cheaper while the stack performance is substantially lower. The thermal management of an air-cooled PEMFC stack is critical. A large amount of heat is side-produced with power and has to be effectively removed by excessive air fed to the stack cathode. This work explores the challenge via...... compact modeling of an air-cooled PEMFC powered telecom back-up system. The presented computational fluid dynamics (CFD) model is three-dimensional (3D), and is based on the commercial CFD package Fluent (ANSYS Inc.). The fuel cell stack is simulated as an anisotropic porous medium and the spatial...

  3. Modeling and Analysis of Transport Processes and Efficiency of Combined SOFC and PEMFC Systems

    DEFF Research Database (Denmark)

    Rabbani, Raja Abid; Rokni, Masoud

    2014-01-01

    A hybrid fuel cell system (~10 kWe) for an average family house including heating is proposed. The investigated system comprises a Solid Oxide Fuel Cell (SOFC) on top of a Polymer Electrolyte Fuel Cell (PEFC). Hydrogen produced from the off-gases of the SOFC can be fed directly to the PEFC....... Simulations for the proposed system were conducted using different fuels. Here, results for natural gas (NG), dimethyl ether (DME) and ethanol as a fuel are presented and analysed. Behaviour of the proposed system is further investigated by comparing the effects of key factors such as utilisation factor...

  4. Spatial proton exchange membrane fuel cell performance under bromomethane poisoning

    Science.gov (United States)

    Reshetenko, Tatyana V.; Artyushkova, Kateryna; St-Pierre, Jean

    2017-02-01

    The poisoning effects of 5 ppm CH3Br in the air on the spatial performance of a proton exchange membrane fuel cell (PEMFC) were studied using a segmented cell system. The presence of CH3Br caused performance loss from 0.650 to 0.335 V at 1 A cm-2 accompanied by local current density redistribution. The observed behavior was explained by possible bromomethane hydrolysis with the formation of Br-. Bromide and bromomethane negatively affected the oxygen reduction efficiency over a wide range of potentials because of their adsorption on Pt, which was confirmed by XPS. Moreover, the PEMFC exposure to CH3Br led to a decrease in the anode and cathode electrochemical surface area (∼52-57%) due to the growth of Pt particles through agglomeration and Ostwald ripening. The PEMFC did not restore its performance after stopping bromomethane introduction to the air stream. However, the H2/N2 purge of the anode/cathode and CV scans almost completely recovered the cell performance. The observed final loss of ∼50 mV was due to an increased activation overpotential. PEMFC exposure to CH3Br should be limited to concentrations much less than 5 ppm due to serious performance loss and lack of self-recovery.

  5. Novel membranes for proton exchange membrane fuel cell operation above 120°C. Final report for period October 1, 1998 to December 31, 1999

    Energy Technology Data Exchange (ETDEWEB)

    Srinivasan, Supramaniam [Princeton Univ., NJ (United States); Lee, Seung-Jae [Princeton Univ., NJ (United States); Costamagna, Paola [Princeton Univ., NJ (United States); Yang, Christopher [Princeton Univ., NJ (United States); Adjemian, Kevork [Princeton Univ., NJ (United States); Bocarsly, Andrew [Princeton Univ., NJ (United States); Ogden, Joan M. [Princeton Univ., NJ (United States); Benziger, Jay [Princeton Univ., NJ (United States)

    2000-05-01

    In this project we investigated the experimental performance of three new classes of membranes, composites of perfluorosulfonic acid polymers with heteropolyacides, hydrated oxides and fast proton conducting glasses, which are promising candidates as electrolytes for proton exchange membrane fuel cells (PEMFCs), capable of operation at temperatures above 120°C. The motivations for PEMFC's operation at this temperature are to: 1) minimize the CO poisoning problem (adsorption of CO onto the platinum catalyst is greatly reduced at these temperatures), 2) find better solutions for the water and thermal management problems in proton exchange membrane fuel cells, 3) find potentially lower cost materials for proton exchange membranes. We prepared and characterized a variety of novel membrane materials. The most promising of these have been evaluated for performance in a single, small area (5cm2) fuel cell run on hydrogen and oxygen. Our results establish the technical feasibility of PEMFC operation above 120°C.

  6. Integrated PEMFC Flow Field Design Concept for Gravity Independent Passive Water Removal, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — The primary power systems for Space Shuttles and future space vehicles are based on fuel cells. Due to inherent fundamental performance, safety and reliability, NASA...

  7. Two-dimensional modeling of electrochemical and transport phenomena in the porous structures of a PEMFC

    Energy Technology Data Exchange (ETDEWEB)

    Sahraoui, Melik [Institut Preparatoire aux Etudes d' Ingenieurs de Tunis (IPEIT) (Tunisia); Kharrat, Chafik; Halouani, Kamel [UR: Micro-Electro-Thermal Systems (METS-ENIS), Industrial Energy Systems Group, Institut Preparatoire aux Etudes d' Ingenieurs de Sfax (IPEIS), University of Sfax, B.P: 1172, 3018 Sfax (Tunisia)

    2009-04-15

    A two-dimensional CFD model of PEM fuel cell is developed by taking into account the electrochemical, mass and heat transfer phenomena occurring in all of its regions simultaneously. The catalyst layers and membrane are each considered as distinct regions with finite thickness and calculated properties such as permeability, local protonic conductivity, and local dissolved water diffusion. This finite thickness model enables to model accurately the protonic current in these regions with higher accuracy than using an infinitesimal interface. In addition, this model takes into account the effect of osmotic drag in the membrane and catalyst layers. General boundary conditions are implemented in a way taking into consideration any given species concentration at the fuel cell inlet, such as water vapor which is a very important parameter in determining the efficiency of fuel cells. Other operating parameters such as temperature, pressure and porosity of the porous structure are also investigated to characterize their effect on the fuel cell efficiency. (author)

  8. On the effective diffusivity of gases in PEM fuel cell electrodes

    International Nuclear Information System (INIS)

    Karan, K.; Pharoah, J.G.

    2004-01-01

    'Full text:' Gas diffusion layer of polymer electrolyte membrane fuel cells (PEMFCs) play a critically important and multiple role as reactant gas distributor, medium for electron and water transport. The most commonly used GDL material is either carbon cloth or carbon paper. Scanning electron microscopic analysis reveals that the GDL microstructure resembles the structure of randomly laid out fibres. Almost all publications on PEMFC models have treated diffusive transport of chemical species through the porous gas diffusion layer (GDL) using correlations originally derived for isotropic granular porous media. Unfortunately, the GDL microstructure does not resemble such a structure. This paper questions the validity of effective diffusivity models used in PEMFC literature and shows that the choice of diffusivity model has significant impact on the prediction of local species fluxes and composition, and consequently on local current densities. (author)

  9. Exergy analysis of an ethanol fuelled proton exchange membrane (PEM) fuel cell system for automobile applications

    Energy Technology Data Exchange (ETDEWEB)

    Song, Shuqin; Douvartzides, Savvas; Tsiakaras, Panagiotis [Department of Mechanical Engineering, School of Engineering, University of Thessaly, Pedion Areos, 383 34 Volos (Greece)

    2005-08-18

    An integrated ethanol fuelled proton exchange membrane fuel cell (PEMFC) power system was investigated following a second law exergy analysis. The system was assumed to have the typical design for automobile applications and was comprised of a vaporizer/mixer, a steam reformer, a CO-shift reactor, a CO-remover (PROX) reactor, a PEMFC and a burner. The exergy analysis was applied for different PEMFC power and voltage outputs assuming the ethanol steam reforming at about 600K and the CO-shift reaction at about 400K. A detailed parametric analysis of the plant is presented and operation guidelines are suggested for effective performance. In every case, the exergy analysis method is proved to allow an accurate allocation of the deficiencies of the subsystems of the plant and serves as a unique tool for essential technical improvements. (author)

  10. CERDEC Fuel Cell Team: Military Transitions for Soldier Fuel Cells

    Science.gov (United States)

    2008-10-27

    Continued Ardica: 20W Wearable PEMFC operating on Chemical Hydrides Spectrum Brands w/ Rayovac: Hydrogen Generators and Alkaline Fuel Cells for AA...running on JP-8 / diesel fuel & 250W RMFC Aspen : 5kWe integrated desulfurizer and JP-8 / diesel fuel processor Altex: 2-kWe integrated desulfurizer...and JP-8 / diesel fuel processor Precision Combustion : 5-kWt integrated desulfurizer and JP-8 and diesel fuel processor Customers Partners Army

  11. Benchmarking Pt-based electrocatalysts for low temperature fuel cell reactions with the rotating disk electrode

    DEFF Research Database (Denmark)

    Pedersen, Christoffer Mølleskov; Escribano, Maria Escudero; Velazquez-Palenzuela, Amado Andres

    2015-01-01

    We present up-to-date benchmarking methods for testing electrocatalysts for polymer exchange membrane fuel cells (PEMFC), using the rotating disk electrode (RDE) method. We focus on the oxygen reduction reaction (ORR) and the hydrogen oxidation reaction (HOR) in the presence of CO. We have chosen...... our experimental methods to provide the most optimal compromise between the ease of carrying out the measurements and for ensuring comparability with PEMFC conditions. For the ORR, the effect of temperature, scan rate, Ohmic drop correction and background subtraction on the catalyst activity...

  12. Platinum Porous Electrodes for Fuel Cells

    DEFF Research Database (Denmark)

    Andersen, Shuang Ma

    Fuel cell energy bears the merits of renewability, cleanness and high efficiency. Proton Exchange Membrane Fuel Cell (PEMFC) is one of the most promising candidates as the power source in the near future. A fine management of different transports and electrochemical reactions in PEM fuel cells...... determination; morphology; oxidation state of components and stability.  Electrode composition investigation: optimization on ionomer content and electrode protonic conductivity.  Interaction between electrode components  Morphology of electrode surface and MEA cross section. The above efforts all contribute...... to a genuine picture of a working PEM fuel cell catalyst layer. These, in turn, enrich the knowledge of Three-Phase-Boundary, provide efficient tool for the electrode selection and eventually will contribute the advancement of PEMFC technology....

  13. Novel variable structure control for the temperature of PEM fuel cell stack based on the dynamic thermal affine model

    International Nuclear Information System (INIS)

    Li Xi; Deng Zhonghua; Wei Dong; Xu Chunshan; Cao Guangyi

    2011-01-01

    Highlights: → The affine state space control-oriented model is designed and realized for the variant structure control (VSC) strategy. → The VSC with rapid-smooth reaching law and rapid-convergent sliding mode is presented for the PEMFC stack temperature. → Numerical results show that the method can control the operating temperature to reach the target value satisfactorily. - Abstract: Dynamic thermal management of proton exchange membrane fuel cell stack (PEMFC) is a very important aspect, which plays an important role on electro-reaction. Its variation also has a significant influence on the performance and lifespan of PEMFC stack. The temperature of stack should be controlled efficiently, which has great impacts on the performance of PEMFC due to the thermal variation. Based on the control-oriented dynamic thermal affine model identified by optimization algorithm, a novel variable structures control (VSC) with rapid-smooth reaching law (RSRL) and rapid-convergent sliding mode (FCSM) is presented for the temperature control system of PEMFC stack. Numerical test results show that the method can control the operating temperature to reach the target value satisfactorily, which proves the effectiveness and robustness of the algorithm.

  14. Durability of Carbon Nanofiber (CNF) & Carbon Nanotube (CNT) as Catalyst Support for Proton Exchange Membrane Fuel Cells

    DEFF Research Database (Denmark)

    Andersen, Shuang Ma; Borghei, Maryam; Lund, Peter

    2013-01-01

    Durability issues have recently been given much attention in Proton Exchange Membrane Fuel Cell (PEMFC) research. It gives fundamental definition for cell life time, capital cost, system stability and technique reliability. Loss of catalyst surface area due to corrosion of supporting material...

  15. Study of a 5 kW PEMFC using experimental design and statistical analysis techniques

    Energy Technology Data Exchange (ETDEWEB)

    Wahdame, B.; Francois, X.; Kauffmann, J.M. [Laboratory of Electrical Engineering and Systems (L2ES), Unite mixte de recherche UTBM and UFC - EA 3898, L2ES-UTBM Batiment F, rue Thierry Mieg, 90010 BELFORT Cedex (France); Candusso, D.; Harel, F.; De Bernardinis, A.; Coquery, G. [The French National Institute for Transport and Safety Research (INRETS), 2 avenue du General Malleret-Joinville, 94 114 ARCUEIL Cedex (France)

    2007-02-15

    Within the framework of the French inter lab SPACT project (Fuel Cell Systems for Transportation Applications), the behavior of a 5 kW PEM fuel cell stack, fed by humidified hydrogen and compressed air, is investigated in a test platform at Belfort, France. A set of polarization curves are recorded, under various conditions of stack temperature, gas pressure, and stoichiometry rates, in order to obtain a kind of cartography, representing the static stack performance. Initially, the tests are defined considering experimental design techniques. In order to study the relative impacts of the physical factors on the fuel cell voltage, some polarization curve results are selected from the static tests available applying experimental design methodology. First, several analyses are used to estimate the impact of the stack temperature, gas pressure, and stoichiometry rate on the fuel cell voltage. Statistical sensitivity analyses (ANOVA) are used to compute, from the available data, the effects and respective contributions of the various physical factors on the stack voltage. The potential for the detection of any interactions between the different parameters is shown. Also, some graphic representations are used to display the results of the statistical analyses made for different current values of the polarization curves. Then, the experimental design method and its associated statistical tools are employed in order to identify the influence of the stack temperature and gas pressure on the fuel cell voltage. Moreover, it is shown how it is possible to reduce the number of experiments needed and how certain optimizations of the fuel cell operating parameters leading to higher performances can be achieved. The work presented aims at showing the suitability of the experimental design method for the characterization, analysis, and improvement of a complex system like a fuel cell generator. The future outlook is proposed in the final part of the paper. The methodologies

  16. Final report on LDRD project : elucidating performance of proton-exchange-membrane fuel cells via computational modeling with experimental discovery and validation.

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Chao Yang (Pennsylvania State University, University Park, PA); Pasaogullari, Ugur (Pennsylvania State University, University Park, PA); Noble, David R.; Siegel, Nathan P.; Hickner, Michael A.; Chen, Ken Shuang

    2006-11-01

    In this report, we document the accomplishments in our Laboratory Directed Research and Development project in which we employed a technical approach of combining experiments with computational modeling and analyses to elucidate the performance of hydrogen-fed proton exchange membrane fuel cells (PEMFCs). In the first part of this report, we document our focused efforts on understanding water transport in and removal from a hydrogen-fed PEMFC. Using a transparent cell, we directly visualized the evolution and growth of liquid-water droplets at the gas diffusion layer (GDL)/gas flow channel (GFC) interface. We further carried out a detailed experimental study to observe, via direct visualization, the formation, growth, and instability of water droplets at the GDL/GFC interface using a specially-designed apparatus, which simulates the cathode operation of a PEMFC. We developed a simplified model, based on our experimental observation and data, for predicting the onset of water-droplet instability at the GDL/GFC interface. Using a state-of-the-art neutron imaging instrument available at NIST (National Institute of Standard and Technology), we probed liquid-water distribution inside an operating PEMFC under a variety of operating conditions and investigated effects of evaporation due to local heating by waste heat on water removal. Moreover, we developed computational models for analyzing the effects of micro-porous layer on net water transport across the membrane and GDL anisotropy on the temperature and water distributions in the cathode of a PEMFC. We further developed a two-phase model based on the multiphase mixture formulation for predicting the liquid saturation, pressure drop, and flow maldistribution across the PEMFC cathode channels. In the second part of this report, we document our efforts on modeling the electrochemical performance of PEMFCs. We developed a constitutive model for predicting proton conductivity in polymer electrolyte membranes and compared

  17. CO tolerance by the PEMFC operational at temperatures up to 200°C

    DEFF Research Database (Denmark)

    Li, Qingfeng; He, Ronghuan; Gao, Ji-An

    2003-01-01

    The CO poisoning effect on carbon-supported platinum catalysts in polymer electrolyte membrane fuel cells has been investigated in a temperature range from 125 to 200°C with the phosphoric acid-doped polybenzimidazole membranes as electrolyte. The effect is very temperature-dependent and can be s...

  18. Development of a PEMFC Power System with Integrated Balance of Plant

    Science.gov (United States)

    Wynne, B.; Diffenderfer, C.; Ferguson, S.; Keyser, J.; Miller, M.; Sievers, B.; Ryan, A.; Vasquez, A.

    2012-01-01

    Autonomous Underwater Vehicles (AUV s) have received increasing attention in recent years as military and commercial users look for means to maintain a mobile and persistent presence in the undersea world. Compact, neutrally buoyant power systems are needed for both small and large vehicles. Batteries are usually employed in these applications, but the energy density and therefore the mission duration are limited with current battery technology. At a certain energy or mission duration requirement, other means to get long duration power become feasible. For example, above 10 kW-hrs liquid oxygen and hydrogen have better specific energy than batteries and are preferable for energy storage as long as a compact system of about 100 W/liter is achievable to convert the chemical energy in these reactants into power. Other reactant forms are possible, such as high pressure gas, chemical hydrides or oxygen carriers, but it is essential that the power system be small and light weight. Recent fuel cell work, primarily focused on NASA applications, has developed power systems that can meet this target power density. Passive flow-through systems, using ejector driven reactant (EDR) flow, integrated into a compact balance of plant have been developed. These systems are thermally and functionally integrated in much the same way as are automotive, air breathing fuel cell systems. These systems fit into the small volumes required for AUV and future NASA applications. Designs have been developed for both a 21" diameter and a larger diameter (LD) AUV. These fuel cell systems occupy a very small portion of the overall energy system, allowing most of the system volume to be used for the reactants. The fuel cell systems have been optimized to use reactants efficiently with high stack efficiency and low parasitic losses. The resulting compact, highly efficient fuel cell system provides exceptional reactant utilization and energy density. Key design variables and supporting test data are

  19. DESENVOLVIMENTO PROFISSIONAL EM COMUNIDADES DE APRENDIZAGEM DOCENTE

    Directory of Open Access Journals (Sweden)

    Vanessa Moreira Crecci

    2018-01-01

    Full Text Available RESUMO: Neste artigo, temos por objetivo relacionar projeções de desenvolvimento profissional e de profissionalidade a diferentes tipos de comunidades de aprendizagem docente. Para tanto, realizamos uma discussão a partir da descrição de diferentes modos de organização dessas comunidades. Em seguida, discorremos sobre as características subjacentes às comunidades fronteiriças, nas quais pesquisadores, professores e futuros professores trabalham de modo colaborativo, sem a regulação da universidade ou da escola. Ao final desta discussão, conclui-se que, por mais que as metodologias sejam aparentemente inovadoras, tornam-se necessárias avaliações dos processos formativos e reflexões cuidadosas sobre os aspectos subjacentes às comunidades de aprendizagem docente.

  20. As Parcerias para o Desenvolvimento Produtivo em saúde na nova agenda de desenvolvimento nacional

    Directory of Open Access Journals (Sweden)

    Laís Silveira Costa

    Full Text Available RESUMO Ao refletir seu caráter sistêmico, as Parcerias para o Desenvolvimento Produtivo (PDP representam uma inflexão na política de saúde e constituem o principal instrumento de ação pública da comunidade de política desenvolvimentista de saúde. Considerando a relevância da saúde para uma trajetória de desenvolvimento nacional que alia competitividade econômica e inclusão social, este artigo visa analisar os elementos político-institucionais que condicionam o desenvolvimento nacional na política de saúde, com destaque para as PDP. Para tanto, utiliza o arcabouço teórico da análise cognitiva das políticas públicas visando identificar como as instituições orientam suas estratégias e as preferências dos atores, e como influenciam os resultados da ação pública.

  1. Proton-Exchange-Membrane Fuel Cell Powerplants Developed and Tested for Exploration Missions

    Science.gov (United States)

    Hoberecht, Mark A.; Pham, Nang T.

    2005-01-01

    Proton-exchange-membrane fuel cell (PEMFC) technology has received major attention for terrestrial applications, such as the automotive and residential markets, for the past 20 years. This attention has significantly advanced the maturity of the technology, resulting in ever more compact, efficient, reliable, and inexpensive PEMFC designs. In comparison to the terrestrial operating environment, the space operating environment is much more demanding. Microgravity to high-gravity loads and the need to use pure oxygen (rather than air) as the fuel cell oxidizer place more stringent demands on PEMFC technology. NASA and its partners from industry are leveraging terrestrial PEMFC advancements by conducting parallel space technology development for future exploration missions. A team from the NASA Glenn Research Center, NASA Johnson Space Center, and NASA Kennedy Space Center recently completed the first phase of a PEMFC powerplant development effort for exploration missions. The industry partners for this phase of the development effort were ElectroChem, Inc., and Teledyne Energy Systems, Inc. Under contract to Glenn, both of these industry partners successfully designed, fabricated, and tested a breadboard PEMFC powerplant in the 1- to 5-kW power range. These powerplants were based on existing company-proprietary fuel cell stack designs, combined with off-the-shelf components, which formed the balance of the powerplant design. Subsequent to the contractor development efforts, both powerplants were independently tested at Johnson to verify operational and performance characteristics, and to determine suitability for further technology development in the second phase of the NASA-led effort. Following the independent NASA testing, Teledyne Energy Systems, Inc., was selected to develop an engineering model PEMFC powerplant. This effort was initiated by the 2nd Generation Reusable Launch Vehicle (RLV) Program Office in 2001; it transitioned to the Next Generation Launch

  2. Proton-Exchange-Membrane Fuel Cell Powerplants Developed and Tested for Exploration Missions

    Science.gov (United States)

    Hoberecht, Mark A.; Pham, Nang T.

    2005-06-01

    Proton-exchange-membrane fuel cell (PEMFC) technology has received major attention for terrestrial applications, such as the automotive and residential markets, for the past 20 years. This attention has significantly advanced the maturity of the technology, resulting in ever more compact, efficient, reliable, and inexpensive PEMFC designs. In comparison to the terrestrial operating environment, the space operating environment is much more demanding. Microgravity to high-gravity loads and the need to use pure oxygen (rather than air) as the fuel cell oxidizer place more stringent demands on PEMFC technology. NASA and its partners from industry are leveraging terrestrial PEMFC advancements by conducting parallel space technology development for future exploration missions. A team from the NASA Glenn Research Center, NASA Johnson Space Center, and NASA Kennedy Space Center recently completed the first phase of a PEMFC powerplant development effort for exploration missions. The industry partners for this phase of the development effort were ElectroChem, Inc., and Teledyne Energy Systems, Inc. Under contract to Glenn, both of these industry partners successfully designed, fabricated, and tested a breadboard PEMFC powerplant in the 1- to 5-kW power range. These powerplants were based on existing company-proprietary fuel cell stack designs, combined with off-the-shelf components, which formed the balance of the powerplant design. Subsequent to the contractor development efforts, both powerplants were independently tested at Johnson to verify operational and performance characteristics, and to determine suitability for further technology development in the second phase of the NASA-led effort. Following the independent NASA testing, Teledyne Energy Systems, Inc., was selected to develop an engineering model PEMFC powerplant. This effort was initiated by the 2nd Generation Reusable Launch Vehicle (RLV) Program Office in 2001; it transitioned to the Next Generation Launch

  3. Durability test with fuel starvation using a Pt/CNF catalyst in PEMFC.

    Science.gov (United States)

    Jung, Juhae; Park, Byungil; Kim, Junbom

    2012-01-05

    In this study, a catalyst was synthesized on carbon nanofibers [CNFs] with a herringbone-type morphology. The Pt/CNF catalyst exhibited low hydrophilicity, low surface area, high dispersion, and high graphitic behavior on physical analysis. Electrodes (5 cm2) were prepared by a spray method, and the durability of the Pt/CNF was evaluated by fuel starvation. The performance was compared with a commercial catalyst before and after accelerated tests. The fuel starvation caused carbon corrosion with a reverse voltage drop. The polarization curve, EIS, and cyclic voltammetry were analyzed in order to characterize the electrochemical properties of the Pt/CNF. The performance of a membrane electrode assembly fabricated from the Pt/CNF was maintained, and the electrochemical surface area and cell resistance showed the same trend. Therefore, CNFs are expected to be a good support in polymer electrolyte membrane fuel cells.

  4. A comparison of Fick and Maxwell-Stefan diffusion formulations in PEMFC gas diffusion layers

    Science.gov (United States)

    Lindstrom, Michael; Wetton, Brian

    2017-01-01

    This paper explores the mathematical formulations of Fick and Maxwell-Stefan diffusion in the context of polymer electrolyte membrane fuel cell cathode gas diffusion layers. The simple Fick law with a diagonal diffusion matrix is an approximation of Maxwell-Stefan. Formulations of diffusion combined with mass-averaged Darcy flow are considered for three component gases. For this application, the formulations can be compared computationally in a simple, one dimensional setting. Despite the models' seemingly different structure, it is observed that the predictions of the formulations are very similar on the cathode when air is used as oxidant. The two formulations give quite different results when the Nitrogen in the air oxidant is replaced by helium (this is often done as a diagnostic for fuel cells designs). The two formulations also give quite different results for the anode with a dilute Hydrogen stream. These results give direction to when Maxwell-Stefan diffusion, which is more complicated to implement computationally in many codes, should be used in fuel cell simulations.

  5. Modeling and Analysis of Transport Processes and Efficiency of Combined SOFC and PEMFC Systems

    Directory of Open Access Journals (Sweden)

    Abid Rabbani

    2014-08-01

    Full Text Available A hybrid fuel cell system (~10 kWe for an average family house including heating is proposed. The investigated system comprises a Solid Oxide Fuel Cell (SOFC on top of a Polymer Electrolyte Fuel Cell (PEFC. Hydrogen produced from the off-gases of the SOFC can be fed directly to the PEFC. Simulations for the proposed system were conducted using different fuels. Here, results for natural gas (NG, dimethyl ether (DME and ethanol as a fuel are presented and analysed. Behaviour of the proposed system is further investigated by comparing the effects of key factors such as utilisation factor, operating conditions, oxygen-to-carbon (O/C ratios and fuel preheating effects on these fuels. The combined system improves the overall electrical conversion efficiency compared with standalone PEFC or SOFC systems. For the combined SOFC and PEFC system, the overall power production was increased by 8%–16% and the system efficiency with one of the fuels is found to be 12% higher than that of the standalone SOFC system.

  6. Simulation of an air conditioning absorption refrigeration system in a co-generation process combining a proton exchange membrane fuel cell

    Energy Technology Data Exchange (ETDEWEB)

    Pilatowsky, I.; Gamboa, S.A.; Rivera, W. [Centro de Investigacion en Energia - UNAM, Temixco, Morelos (Mexico); Romero, R.J. [Centro de Investigacion en Ingenieria y Ciencias Aplicadas - UAEM, Cuernavaca, Morelos (Mexico); Isaza, C.A. [Universidad Pontificia Bolivariana, Medellin (Colombia). Instituto de Energia y Termodinamica; Sebastian, P.J. [Centro de Investigacion en Energia - UNAM, Temixco, Morelos (Mexico); Cuerpo Academico de Energia y Sustentabilidad-UP Chiapas, Tuxtla Gutierrez, Chiapas (Mexico); Moreira, J. [Cuerpo Academico de Energia y Sustentabilidad-UP Chiapas, Tuxtla Gutierrez, Chiapas (Mexico)

    2007-10-15

    In this work, a computer simulation program was developed to determine the optimum operating conditions of an air conditioning system during the co-generation process. A 1 kW PEMFC was considered in this study with a chemical/electrical theoretical efficiency of 40% and a thermal efficiency of 30% applying an electrical load of 100%. A refrigeration-absorption cycle (RAC) operating with monomethylamine-water solutions (MMA-WS), with low vapor generation temperatures (up to 80 C) is proposed in this work. The computer simulation was based on the refrigeration production capacity at the maximum power capacity of the PEMFC. Heat losses between the fuel cell and the absorption air conditioning system at standard operating conditions were considered to be negligible. The results showed the feasibility of using PEMFC for cooling, increasing the total efficiency of the fuel cell system. (author)

  7. Anticorrosion Coating of Carbon Nanotube/Polytetrafluoroethylene Composite Film on the Stainless Steel Bipolar Plate for Proton Exchange Membrane Fuel Cells

    Directory of Open Access Journals (Sweden)

    Yoshiyuki Show

    2013-01-01

    Full Text Available Composite film of carbon nanotube (CNT and polytetrafluoroethylene (PTFE was formed from dispersion fluids of CNT and PTFE. The composite film showed high electrical conductivity in the range of 0.1–13 S/cm and hydrophobic nature. This composite film was applied to stainless steel (SS bipolar plates of the proton exchange membrane fuel cell (PEMFC as anticorrosion film. This coating decreased the contact resistance between the surface of the bipolar plate and the membrane electrode assembly (MEA of the PEMFC. The output power of the fuel cell is increased by 1.6 times because the decrease in the contact resistance decreases the series resistance of the PEMFC. Moreover, the coating of this composite film protects the bipolar plate from the surface corrosion.

  8. Integrated HT-PEMFC and multi-fuel reformer for micro CHP. Final report

    Energy Technology Data Exchange (ETDEWEB)

    2010-07-01

    The project was initiated in April 2008 and completed by the end of March 2010. The project consortium consisted of: Dantherm Power, Serenergy and Department of Energy Technology at Aalborg University (project manager). The activities were coordinated with the project ''Nordjysk H2FC Center'' funded by the Region of Northern Jutland. A number of experimental characterization methods were developed through this project to improve the understanding in fuel cell performance under different operating conditions. In particular the application of Electrochemical Impedance Spectroscopy was found useful and lead to new information about individual losses in the fuel cell. Techniques to measure local temperatures of the MEA were also successfully developed. Durability studies were made on single cells as well as complete stacks. A dedicated test facility was constructed in a container to isolate the test from disturbances that occur in the laboratory. The stack tests were run for just above 6 months with few interruptions and it was found that single cell and stack degradation rates were comparable. Operation temperature was found to have the most pronounced influence on degradation. The information formed the basis for a simple modeling tool to optimize the stack operating temperature versus reformate gas CO concentration. The activities on multi-fuel reformer development were mostly focused on two issues; manufacturability and analyses of flow distribution and heat transfer. The latter was required since these areas these turned out to cause challenges in the reactor design. Through a combination of experimental tests, CFD analyses and flow network modeling design modifications were suggested to improve flow distribution on both the flue gas side and the reformate side. Most of these design changes were not validated in this project through the construction and test of a new reformer. In spite of the problems identifies, the reformed successfully

  9. Approaches and Recent Development of Polymer Electrolyte Membranes For Fuel Cells Operational Above 100°C

    DEFF Research Database (Denmark)

    Li, Qingfeng; He, Ronghuan; Jensen, Jens Oluf

    2003-01-01

    by sulfonation. The sulfonated hydrocarbons and their inorganic composites are potentially promising for high-temperature operation. High conductivities have been obtained at temperatures up to 180 °C. Acid-base complex membranes constitute another class of electrolyte membranes. A high-temperature PEMFC based......The state-of-the-art of polymer electrolyte membrane fuel cell (PEMFC) technology is based on perfluorosulfonic acid (PFSA) polymer membranes operating at a typical temperature of 80 °C. Some of the key issues and shortcomings of the PFSA-based PEMFC technology are briefly discussed. These include...... water management, CO poisoning, hydrogen, reformate and methanol as fuels, cooling, and heat recovery. As a means to solve these shortcomings, hightemperature polymer electrolyte membranes for operation above 100 °C are under active development. This treatise is devoted to a review of the area...

  10. Meios e fins do desenvolvimento para Celso Furtado

    Directory of Open Access Journals (Sweden)

    Fabio Antonio de Campos

    2014-10-01

    Full Text Available O objetivo desse artigo é expor o conceito de desenvolvimento para Celso Furtado. Para tanto, nos interessa apresentar o desenvolvimento nacional como um fim em sua abordagem sobre a formação social brasileira Para atingir tal estágio, os meios para o autor seriam assegurados por um típico desenvolvimento capitalista. Dentro dessa problemática, mostraremos também o alcance e os limites dessa concepção para o caráter dependente e subdesenvolvido do capitalismo brasileiro.

  11. DIREITOS HUMANOS, DESENVOLVIMENTO SUSTENTÁVEL E SUSTENTABILIDADE

    OpenAIRE

    Carvalho, Sonia Aparecida de; Silva, Denival Francisco da; Adolfo, Luiz Gonzaga Silva

    2015-01-01

    Este artigo trata da relação intrínseca entre os direitos humanos, o desenvolvimento sustentável e a sustentabilidade. Seu objetivo geral consiste em analisar o modelo de desenvolvimento implementado e a necessária proteção e preservação do meio ambiente ligado à defesa dos direitos humanos. Os objetivos específicos pretendem investigar a distinção dos termos sustentabilidade e desenvolvimento sustentável, como a concretização do direito à sustentabilidade, os critérios e as dimensões da sust...

  12. Development of a computational model applied to a unitary 144 CM{sup 2} proton exchange membrane fuel cell; Desenvolvimento de um modelo numerico computacional aplicado a uma celula a combustivel unitaria de 144 CM{sup 2} tipo PEM

    Energy Technology Data Exchange (ETDEWEB)

    Robalinho, Eric

    2009-07-01

    This work presents the development of a numerical computer model and methodology to study and design polymeric exchange membrane fuel cell - PEM. For the validation of experimental results, a sequence of routines, appropriate to fit the data obtained in the laboratory, was described. At the computational implementation it was created a new strategy of coupling two 3-dimensional models to satisfy the requirements of the comprehensive model of the fuel cell, including its various geometries and materials, as well as the various physical and chemical processes simulated. To effective assessment of the real cell analogy with numerical model, numerical studies were carried out. Comparisons with values obtained in the literature, characterization of variables through laboratory experiments and estimates from models already tested in the literature were also performed. Regarding the experimental part, a prototype of a fuel cell unit of 144 cm{sup 2} of geometric area was designed, produced and operated at laboratory with the purpose of validating the numerical computer model proposed, with positive results. The results of simulations for the 2D and 3D geometries proposed are presented in the form of polarization curves, highlighting the catalytic layer model based on the geometry of agglomerates. Parametric and sensitivity studies are presented to illustrate the change in performance of the fuel cell studied. The final model is robust and useful as a tool for design and optimization of PEM type fuel cells in a wide range of operating conditions. (author)

  13. Development of a computational model applied to a unitary 144 cm{sup 2} proton exchange membrane fuel cell; Desenvolvimento de um modelo numerico computacional aplicado a uma celula a combustivel unitaria de 144 CM{sup 2} tipo PEM

    Energy Technology Data Exchange (ETDEWEB)

    Robalinho, Eric

    2009-07-01

    This work presents the development of a numerical computer model and methodology to study and design polymeric exchange membrane fuel cell - PEM. For the validation of experimental results, a sequence of routines, appropriate to fit the data obtained in the laboratory, was described. At the computational implementation it was created a new strategy of coupling two 3-dimensional models to satisfy the requirements of the comprehensive model of the fuel cell, including its various geometries and materials, as well as the various physical and chemical processes simulated. To effective assessment of the real cell analogy with numerical model, numerical studies were carried out. Comparisons with values obtained in the literature, characterization of variables through laboratory experiments and estimates from models already tested in the literature were also performed. Regarding the experimental part, a prototype of a fuel cell unit of 144 cm of geometric area was designed, produced and operated at laboratory with the purpose of validating the numerical computer model proposed, with positive results. The results of simulations for the 2D and 3D geometries proposed are presented in the form of polarization curves, highlighting the catalytic layer model based on the geometry of agglomerates. Parametric and sensitivity studies are presented to illustrate the change in performance of the fuel cell studied. The final model is robust and useful as a tool for design and optimization of PEM type fuel cells in a wide range of operating conditions. (author)

  14. Ultrahigh PEMFC performance of a thin-film, dual-electrode assembly with tailored electrode morphology.

    Science.gov (United States)

    Jung, Chi-Young; Kim, Tae-Hyun; Yi, Sung-Chul

    2014-02-01

    A dual-electrode membrane electrode assembly (MEA) for proton exchange membrane fuel cells with enhanced polarization under zero relative humidity (RH) is fabricated by introducing a phase-separated morphology in an agglomerated catalyst layer of Pt/C (platinum on carbon black) and Nafion. In the catalyst layer, a sufficient level of phase separation is achieved by dispersing the Pt catalyst and the Nafion dispersion in a mixed-solvent system (propane-1,2,3-triol/1-methyl-2-pyrrolidinone).The high polymer chain mobility results in improved water uptake and regular pore-size distribution with small pore diameters. The electrochemical performance of the dual-film electrode assembly with different levels of phase separation is compared to conventional electrode assemblies. As a result, good performance at 0 % RH is obtained because self-humidification is dramatically improved by attaching this dense and phase-separated catalytic overlayer onto the conventional catalyst layer. A MEA prepared using the thin-film, dual-layered electrode exhibits 39-fold increased RH stability and 28-fold improved start-up recovery time during the on-off operation relative to the conventional device. We demonstrate the successful operation of the dual-layered electrode comprised of discriminatively phase-separated agglomerates with an ultrahigh zero RH fuel-cell performance reaching over 95 % performance of a fully humidified MEA. Copyright © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. Performance improvement of a PEMFC system controlling the cathode outlet air flow

    Energy Technology Data Exchange (ETDEWEB)

    Feroldi, Diego; Serra, Maria; Riera, Jordi [Institut de Robotica i Informatica Industrial, Universitat Politecnica de Catalunya-Consejo Superior de Investigaciones Cientificas, C. Llorens i Artigas 4, 08028 Barcelona (Spain)

    2007-06-10

    This paper presents a stationary and dynamic study of the advantages of using a regulating valve for the cathode outlet flow in combination with the compressor motor voltage as manipulated variables in a fuel cell system. At a given load current, the cathode input and output flow rate determine the cathode pressure and stoichiometry, and consequently determine the oxygen partial pressure, the generated voltage and the compressor power consumption. In order to maintain a high efficiency during operation, the cathode output regulating valve has to be adjusted to the operating conditions, specially marked by the current drawn from the stack. Besides, the appropriate valve manipulation produces an improvement in the transient response of the system. The influence of this input variable is exploited by implementing a predictive control strategy based on dynamic matrix control (DMC), using the compressor voltage and the cathode output regulating valve as manipulated variables. The objectives of this control strategy are to regulate both the fuel cell voltage and oxygen excess ratio in the cathode, and thus, to improve the system performance. All the simulation results have been obtained using the MATLAB-Simulink environment. (author)

  16. Local transport phenomena and cell performance of PEM fuel cells with various serpentine flow field designs

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Xiao-Dong [Department of Thermal Engineering, School of Mechanical Engineering, University of Science and Technology Beijing, Beijing 100083 (China); Duan, Yuan-Yuan [Key Laboratory for Thermal Science and Power Engineering of Ministry of Education, Tsinghua University, Beijing 100084 (China); Yan, Wei-Mon [Department of Mechatronic Engineering, Huafan University, Taipei 22305 (China); Peng, Xiao-Feng [Laboratory of Phase Change and Interfacial Transport Phenomena, Tsinghua University, Beijing 100084 (China)

    2008-01-03

    The flow field design in bipolar plates is very important for improving reactant utilization and liquid water removal in proton exchange membrane fuel cells (PEMFCs). A three-dimensional model was used to analyze the effect of the design parameters in the bipolar plates, including the number of flow channel bends, number of serpentine flow channels and the flow channel width ratio, on the cell performance of miniature PEMFCs with the serpentine flow field. The effect of the liquid water formation on the porosities of the porous layers was also taken into account in the model while the complex two-phase flow was neglected. The predictions show that (1) for the single serpentine flow field, the cell performance improves as the number of flow channel bends increases; (2) the single serpentine flow field has better performance than the double and triple serpentine flow fields; (3) the cell performance only improves slowly as the flow channel width increases. The effects of these design parameters on the cell performance were evaluated based on the local oxygen mass flow rates and liquid water distributions in the cells. Analysis of the pressure drops showed that for these miniature PEMFCs, the energy losses due to the pressure drops can be neglected because they are far less than the cell output power. (author)

  17. Characterization of proton exchange membrane fuel cell anode catalysts prepared by colloid method

    Energy Technology Data Exchange (ETDEWEB)

    Franco, E.G.; Dantas-Filho, P.L.; Burani, G.F. [Universidade de Sao Paulo (IEE/USP), Sao Paulo, SP (Brazil). Instituto de Eletrotecnica e Energia

    2009-07-01

    Full text: Anode catalysts for Proton Exchange Membrane Fuel Cell (PEMFC) were synthesized by the colloid method and their structure was investigated by transmission electron microscopy (TEM), energy dispersive analyses (EDS), X-ray Diffraction (XRD). The electrochemical behavior of the anode catalyst was analyzed by cyclic voltammetry (CV) and polarization curves (UxI). (author)

  18. Design of flow-field patterns for proton exchange membrane fuel cell application

    International Nuclear Information System (INIS)

    Rosli, M.I.; Wan Ramli Wan Daud; Kamaruzzaman Sopian; Jaafar Sahari

    2006-01-01

    Fuel cells are electrochemical devices that produce electricity at high efficiency without combustion. Fuel cells are emerging as viable candidates as power sources in many applications, including road vehicles, small-scale power stations, and possibly even portable electronics. This paper addresses the design of flow-field patterns for proton exchange membrane fuel cell (PEMFC). The PEMFC is a low-temperature fuel cell, in which a proton conductive polymer membrane is used as the electrolyte. In PEMFC, flow-field pattern is one important thing that effects the performance of PEMFC. This paper present three types of flow-field pattern that will be consider to be testing using CFD analysis and by experimental. The design look detail on to their shape and dimension to get the best pattern in term of more active electrode area compare to electrode area that will be used. Another advantage and disadvantage for these three type of flow-field patterns from literature also compared in this paper

  19. Estimation of membrane hydration status for standby proton exchange membrane fuel cell systems by impedance measurement

    DEFF Research Database (Denmark)

    Bidoggia, Benoit; Rugholt, Mark; Nielsen, Morten Busk

    2014-01-01

    Fuel cells are getting growing interest in both backup systems and electric vehicles. Although these systems are characterized by long periods of inactivity, they must be able to start at any instant in the shortest time. However, the membrane of which PEMFCs are made tends to dry out when not in...

  20. Preparation and characterization of Nafion/titanium dioxide nanocomposite membranes for proton exchange membrane fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Eroglu, Inci; Devrim, Yilser; Erkan, Serdar [Middle East Technical Univ., Ankara (Turkey). Dept. of Chemical Engineering; Bac, Nurcan [Yeditepe Univ., Istanbul (Turkey). Dept. of Chemical Engineering

    2010-07-01

    In the present study, Nafion/Titanium dioxide (TiO{sub 2}) nanocomposite membranes for use in proton exchange membrane fuel cells (PEMFC) were investigated. Nafion/TiO{sub 2} membranes were prepared using the recasting procedure. The composite membranes have been characterized by thermal analysis, XRD, SEM, proton conductivity measurements and single cell performance. Thermal analysis results showed that the composite membranes have good thermal properties. The introduction of the inorganic filler supplies the composite membrane with a good thermal resistance. The physico-chemical properties studied by means of scanning electron microscopy (SEM) and X-ray diffraction (XRD) techniques have proved the uniform and homogeneous distribution of TiO{sub 2} and the consequent enhancement of crystalline character of these membranes. The energy dispersive spectra (EDS) analysis indicated that the distribution of Ti element on the surface of the composite membrane was uniform. Performances of fabricated Membrane electrode assembly (MEA)'s measured via the PEMFC test station built at METU Fuel Cell Technology Laboratory. A single cell with a 5 cm{sup 2} active area was used in the experiments. These results should be conducive to the preparation of membranes suitable for PEMFC. We believe that Nafion/TiO{sub 2} nano composite membranes have good prospects for use in PEMFC. (orig.)

  1. Dynamic Thermal Model And Control Of A Pem Fuel Cell System

    DEFF Research Database (Denmark)

    Liso, Vincenzo; Nielsen, Mads Pagh

    2013-01-01

    A lumped parameter dynamic model is developed for predicting the stack performance, temperatures of the exit reactant gases and coolant liquid outlet in a proton-exchange membrane fuel cell (PEMFC) system. The air compressor, humidifier and cooling heat exchanger models are integrated to study...... the performance of the thermal system, especially when investigating applications that have highly dynamic operating conditions....

  2. Fuel Cells: A Real Option for Unmanned Aerial Vehicles Propulsion

    OpenAIRE

    González_Espasandín, Oscar; Leo Mena, Teresa de Jesus; Navarro Arevalo, Emilio

    2013-01-01

    The possibility of implementing fuel cell technology in Unmanned Aerial Vehicle (UAV) propulsion systems is considered. Potential advantages of the Proton Exchange Membrane or Polymer Electrolyte Membrane (PEMFC) and Direct Methanol Fuel Cells (DMFC), their fuels (hydrogen and methanol), and their storage systems are revised from technical and environmental standpoints. Some operating commercial applications are described. Main constraints for these kinds of fuel cells are analyzed in order t...

  3. Experimental Characterization of the Poisoning Effects of Methanol-Based Reformate Impurities on a PBI-Based High Temperature PEM Fuel Cell

    DEFF Research Database (Denmark)

    Araya, Samuel Simon; Andreasen, Søren Juhl; Kær, Søren Knudsen

    2012-01-01

    In this work the effects of reformate gas impurities on a H3PO4-doped polybenzimidazole (PBI) membrane-based high temperature proton exchange membrane fuel cell (HT-PEMFC) are studied. A unit cell assembly with a BASF Celtec®-P2100 high temperature membrane electrode assembly (MEA) of 45 cm2 active...

  4. Theoretical studies of Pt-Ti nanoparticles for potential use as PEMFC electrocatalysts.

    Science.gov (United States)

    Jennings, Paul C; Pollet, Bruno G; Johnston, Roy L

    2012-03-07

    A theoretical investigation is presented of alloying platinum with titanium to form binary Pt-Ti nanoalloys as an alternative to the expensive pure platinum catalysts commonly used for Proton Exchange Membrane Fuel Cell cathode electrocatalysts. Density Functional Theory calculations are performed to investigate compositional effects on structural properties as well as Oxygen Reduction Reaction kinetics and poisoning effects. High symmetry A(32)-B(6) clusters are studied to investigate structural properties. From these structures binding energies of hydroxyl and carbon monoxide are studied on a range of sites on the surface of the clusters. Promising results are obtained suggesting that the bimetallic Pt-Ti nanoalloys may exhibit enhanced properties compared to pure platinum catalysts.

  5. Optimization by simulation and development of solar cells with aluminium paste rear emitter and diffusion in conveyor furnace; Otimizacao por simulacao e desenvolvimento de celulas solares com emissor posterior formado por pasta de aluminio e difusao em forno de esteira

    Energy Technology Data Exchange (ETDEWEB)

    Mallmann, Ana Paula

    2011-01-15

    Photovoltaic solar energy is the direct conversion of solar energy into electricity and it has low impact to the environment during electric energy production. The main device of this technology is the solar cell and silicon is the substrate most used. The solar cells are electrically connected and encapsulated in order to form the photovoltaic module. The aims of this thesis are to optimize, develop and to analyse n{sup +}np{sup +} solar cells processed in n type Si-PV-FZ and with aluminum rear emitter formed in belt furnace. The optimization of solar cells by simulation is an important step before the device development. The software PC-1D and another program developed using Visual Basic language were used. Considering a metal grid formed by evaporation technique in vacuum ambient an efficiency of 16.8 % may be achieved. With screen printed grid, 15.8 % efficient solar cells were obtained. From the simulation results it was found that the screen printing metallization may become more viable than evaporation technique because there is low difference in the efficiency and the screen printing is a simpler technique. The experimental optimization of silicon wafers texture process resulted in reflectance of 12 %. This value is typical for monocrystalline silicon with textured surface. Experimental optimization of phosphorus front surface field shows a sheet resistance of (36 {+-} 4) {omega}/ for this region. This region was formed in a thermal step in a conventional furnace with POCl{sub 3}. It was found that after the phosphorus diffusion occurred gettering to specific temperature and time. It was verified that the minority carrier lifetime in the final of processing is similar to the initial value. The influence of steps sequence of front silver paste firing and rear diffusion/firing aluminium paste, of surface passivation and the influence of dry air flow during the aluminium paste diffusion/firing, of aluminium paste diffusion/firing temperature and of belt speed

  6. Carcinoma de células escamosas oral - contribuição de vírus oncogênicos e alguns marcadores moleculares no desenvolvimento e prognóstico da lesão: uma revisão Oral squamous cell carcinoma - contribution of oncogenic virus and some molecular markers in the development and prognosis of the lesion: a review

    Directory of Open Access Journals (Sweden)

    Beatriz da Rocha Miranda Venturi

    2004-06-01

    Full Text Available O carcinoma de células escamosas oral é um evento de muitas etapas, cuja incidência cresce continuamente, particularmente em jovens, numa amplitude que não pode ser completamente explicada pelo aumento da exposição a fatores de risco, como o tabaco e o álcool. Recentes investigações moleculares sugerem que existem múltiplos eventos genéticos, e vírus oncogênicos que são capazes de alterar as funções normais de oncogenes e genes de supressão tumoral. O objetivo deste artigo foi revisar o conhecimento atual sobre o papel do papilomavírus humano (HPV, Epstein-Barr vírus (EBV, P53 e telomerase no desenvolvimento e prognóstico do carcinoma de células escamosas oral.Oral squamous cell carcinoma is a multistep event that continues to increase in incidence, particularly in the young, and to an extent that cannot be fully explained by increased exposure to known risk factors, as tobacco or alcohol. Recent molecular investigations suggest that there are multiple genetic events, and oncogenic virus that are able to alter the normal functions of oncogenes and tumor suppressor genes. The aim of the present article was to review the current knowledge on the role of Human papillomavirus (HPV, Epstein-Barr virus (EBV, P53 and telomerase in the development and prognosis of the oral squamous cell carcinoma.

  7. Characterization and Modeling of a Methanol Reforming Fuel Cell System

    DEFF Research Database (Denmark)

    Sahlin, Simon Lennart

    topologies is the Reformed Methanol Fuel Cell (RMFC) system that operates on a mix of methanol and water. The fuel is reformed with a steam reforming to a hydrogen rich gas, however with additional formation of Carbon Monoxide and Carbon Dioxide. High Temperature Polymer Electrolyte Membrane Fuel Cell (HT......-PEMFC) has the benefit of being resistant to CO poisoning. The HT-PEM fuel cell operates at elevated temperatures (above 100 oC) and therefore uses phosphoric acid as a proton conductor.  Using a HT-PEMFC in a RMFC system enables the use of exhaust gas from the fuel cell in a catalytic burner which is able...... to heat up the steam reforming process. However, utilizing the excess hydrogen in the system complicates the RMFC system as the amount of hydrogen can vary depending on the fuel methanol supply, fuel cell load and the reformer gas composition. This PhD study has therefore been involved in investigating...

  8. Biotecnologia aplicada ao desenvolvimento de vacinas

    Directory of Open Access Journals (Sweden)

    Mariana de Oliveira Diniz

    2010-01-01

    Full Text Available As vacinas representam a estratégia de intervenção com a melhor relação custo-benefício até hoje aplicada em saúde pública. Avanços biotecnológicos em diversas áreas de pesquisa têm contribuído para o desenvolvimento de formulações mais seguras e eficazes. Além disso, a aplicação de ferramentas biotecnológicas no desenvolvimento de vacinas tem provocado mudanças na maneira como pensamos e produzimos esses reagentes tanto para uso em humanos como em animais. Essas tecnologias trazem perspectivas de que, em futuro próximo, vacinas para o controle de doenças infecciosas e degenerativas ainda não passíveis de prevenção possam estar disponíveis. Em particular, vacinas com efeitos terapêuticos, embora representem um enorme desafio a ser vencido, tornam-se cada vez próximas da realidade e, certamente, terão um impacto enorme no tratamento de diversas doenças, como em algumas formas de câncer.Vaccines represent the intervention strategy with the best cost-benefit ratio so far applied in public health. Biotechnological advances in various areas of vaccine research have contributed to the development of safer and more effective formulations. Moreover, application of biotechnology tools to vaccine development has caused changes in the way we think and produce these reagents both for use in humans and animals. Such technologies bring renewed perspectives that, in the near future, vaccines for the control of several non-preventable infectious and degenerative diseases will be available. In particular, the development of vaccines with therapeutic effects, although representing a huge challenge, are getting closer to reality and will have a tremendous impact in the treatment of several diseases such as some cancer forms.

  9. Pt–Ni/C catalysts using different carbon supports for the cathode of the proton exchange membrane fuel cell (PEMFC)

    International Nuclear Information System (INIS)

    Wu, Huimin; Wexler, David; Liu, Huakun

    2012-01-01

    20 wt.% PtNi/C catalysts were prepared using a chemical reduction method, with Vulcan XC-72 conducting furnace black and graphene as the carbon support, respectively, and compared to commercial BASF 20 wt.% Pt/C (using Vulcan XC-72 carbon as support). The materials were characterized by X-ray diffraction, and transmission electron microscopy (TEM). The electrochemical performance of the PtNi/C catalysts was evaluated by cyclic voltammetry, and by steady-state measurements. Electrochemical measurements indicate that the PtNi nanocatalysts exhibited improved activity in the oxygen reduction reaction (ORR) on graphene compared with those on Vulcan XC-72 carbon, and graphene could potentially provide much higher durability than XC-72. This suggests that graphene is a more effective catalyst support than Vulcan XC-72 carbon. -- Highlights: ► PtNi/C catalysts were prepared on C = Vulcan XC-72 carbon black and graphene. ► The PtNi/C exhibited enhanced catalytic activity compared to Pt/XC-72. ► The performance of PtNi/Graphene is higher than that of PtNi/XC-72. ► Graphene could potentially provide much higher durability than XC-72.

  10. Rede de Protagonismo Local para o Desenvolvimento Global

    DEFF Research Database (Denmark)

    Weber, Ángela; Hermann, Roberto Rivas

    Este artigo pretende fazer uma reflexão sobre metodologia a ser desenvolvida e utilizada num projeto de desenvolvimento local, através das ações protagonizadas pela própria comunidade. Para isso parte de uma discussão sobre o conceito de desenvolvimento sustentável, e a seguir propõe a busca de f...

  11. Thermal analysis of cylindrical natural-gas steam reformer for 5 kW PEMFC

    Science.gov (United States)

    Jo, Taehyun; Han, Junhee; Koo, Bonchan; Lee, Dohyung

    2016-11-01

    The thermal characteristics of a natural-gas based cylindrical steam reformer coupled with a combustor are investigated for the use with a 5 kW polymer electrolyte membrane fuel cell. A reactor unit equipped with nickel-based catalysts was designed to activate the steam reforming reaction without the inclusion of high-temperature shift and low-temperature shift processes. Reactor temperature distribution and its overall thermal efficiency depend on various inlet conditions such as the equivalence ratio, the steam to carbon ratio (SCR), and the fuel distribution ratio (FDR) into the reactor and the combustor components. These experiments attempted to analyze the reformer's thermal and chemical properties through quantitative evaluation of product composition and heat exchange between the combustor and the reactor. FDR is critical factor in determining the overall performance as unbalanced fuel injection into the reactor and the combustor deteriorates overall thermal efficiency. Local temperature distribution also influences greatly on the fuel conversion rate and thermal efficiency. For the experiments, the operation conditions were set as SCR was in range of 2.5-4.0 and FDR was in 0.4-0.7 along with equivalence ratio of 0.9-1.1; optimum results were observed for FDR of 0.63 and SCR of 3.0 in the cylindrical steam reformer.

  12. New insights into proton surface mobility processes in PEMFC catalysts using isotopic exchange methods.

    Science.gov (United States)

    Ferreira-Aparicio, Paloma

    2009-09-01

    The surface chemistry and the adsorption/desorption/exchange behavior of a proton-exchange membrane fuel cell catalyst are analyzed as a case study for the development of tailor-made support materials of enhanced performance and stability. By using H2, D2, and CO as probe molecules, the relevance of some surface functional groups of the catalyst support on several diffusion processes taking place during the adsorption is shown. Sulfonic groups associated with the vulcanized carbon black surface have been detected by means of spectroscopic techniques (X-ray photoelectron spectroscopy and Fourier transform infrared spectroscopy) and by analysis of the desorbed products during temperature-programmed desorption tests by mass spectrometry. Such hydrophilic species have been observed to favor proton surface mobility and exchange with Pt-adsorbed deuterium even in the presence of adsorbed CO. This behavior is relevant both for the proper characterization of these kinds of catalysts using adsorption probes and for the design of new surface-modified carbon supports, enabling alternative proton-transfer pathways throughout the catalytic layers toward the membrane.

  13. Synthesis and Development of Modified OMC-Supported Platinum Electrocatalyst for PEMFC

    Science.gov (United States)

    Muonagolu, Emeka Paul

    Ordered mesoporous carbon (OMC) has been considered as a promising Platinum catalyst support because of its large surface area, uniform ordered hexagonal mesopores, porous structure and high electrical conductivity. Graphitization of the walls of OMC is vital when the electrical conductivity of the catalyst is the main concern. The objective of this work was to improve the electrical conductivity of the ordered mesoporous carbon (OMC) support by utilizing transition metals such as Ni, Co and Fe to graphitize the pore walls of OMC via catalytic graphitization. Metal modified OMCs have been synthesized following two steps. First step is synthesizing metal modified SBA-15 as a template containing 10wt% transition metals (Ni, Co, Fe) and TEOS as a source of silica followed by calcination. The second step is introducing sucrose as the carbon source into the pores of the silica template followed by carbonization at 900°C and removal of the silica template using hydrofluoric acid. The synthesized Metal modified OMCs were characterized using Brunaeur Emmit Teller (BET) analysis, X-ray diffraction (XRD), transmission electron microscopy (TEM), Raman spectroscopy. Surface area for the metal modified --OMC was found around 1300--1500m 2/g and pore sizes in the range of 3--4nm. The membrane electrode assembly (MEA) was prepared using the synthesized electrocatalyst and was used to evaluate the performance of the catalyst by testing it on the fuel cell test station. The results were compared to that of commercial catalyst.

  14. Research of General Deduction Optimization on PEMFC Manufacturing with Fuzzy Linguistic Analysis

    Directory of Open Access Journals (Sweden)

    Tian-Syung Lan

    2014-01-01

    Full Text Available In control questions, multiquality parameters are the most suitable, as they are everlasting in highly complex misalignment relations; the relationship between the parameter and quality of mutual influence is complex, and often massive redundant operations must be achievable by the test installation. Because the most suitable multiquality parameter is difficult to achieve, this study designates the proton exchange membrane fuel cell as the topic, takes the inlet temperature, inlet pressure, and incoming flow speed as the controlling elements, uses conformity fuzzy meaning analysis and the ideal solution similar order by chance law (TOPSIS, and discusses the parameters to control the influences of the quality goal. As outlet temperature, outlet pressure, pressure drop do not operate after the experiment, this study uses the meaning deduction method and develops a set of the most suitable control mechanisms. The research results show that this study develops a quality decision scheme for a set of meanings by using the misalignment and a high order complexity question. It also penetrates the meaning method, which guarantees that the quality and experimental efficiency may elevate the competitive power of science and technological undertakings development, effectively economize costs, and provide a set of economies and perspectives. The multiqualities are the most suitable control plan which meets the demands of practice.

  15. Development of materials for use in solid oxid fuel cells anodes using renewable fuels in direct operation; Desenvolvimento de materiais ceramicos aplicados em anodos de celulas a combustivel de oxidos solidos para operacao direta com combustiveis renovaveis

    Energy Technology Data Exchange (ETDEWEB)

    Lima, D.B.P.L. de [Instituto Federal do Parana (IFPR), PR (Brazil); Florio, D.Z. de; Bezerra, M.E.O., E-mail: daniela.bianchi@ifpr.edu.br [Universidade Federal do ABC (UFABC), Santo Andre, SP (Brazil)

    2016-07-01

    Fuel cells produce electrical current from the electrochemical combustion of a gas or liquid (H2, CH4, C2H5OH, CH3OH, etc.) inserted into the anode cell. An important class of fuel cells is the SOFC (Solid Oxide Cell Fuel). It has a ceramic electrolyte that transports protons (H +) or O-2 ions and operating at high temperatures (500-1000 °C) and mixed conductive electrodes (ionic and electronic) ceramics or cermets. This work aims to develop anodes for fuel cells of solid oxide (SOFC) in order to direct operations with renewable fuels and strategic for the country (such as bioethanol and biogas). In this context, it becomes important to study in relation to the ceramic materials, especially those that must be used in high temperatures. Some types of double perovskites such as Sr2MgMoO6 (or simply SMMO) have been used as anodes in SOFC. In this study were synthesized by the polymeric precursor method, analyzed and characterized different ceramic samples of families SMMO, doped with Nb, this is: Sr2 (MgMo)1-xNbxO6 with 0 ≤ x ≤ 0.2. The materials produced were characterized by various techniques such as, thermal analysis, X-ray diffraction and scanning electron microscopy, and electrical properties determined by dc and ac measurements in a wide range of temperature, frequency and partial pressure of oxygen. The results of this work will contribute to a better understanding of advanced ceramic properties with mixed driving (electronic and ionic) and contribute to the advancement of SOFC technology operating directly with renewable fuels. (author)

  16. Efeito dos dióxidos de enxofre e de nitrogênio no desempenho de uma célula a combustível de membrana de intercâmbio de prótons Effect of sulfur and nitrogen dioxides on the performance of a proton exchange membrane fuel cell

    Directory of Open Access Journals (Sweden)

    Thiago Lopes

    2008-01-01

    Full Text Available There is presently much interest in the clean and efficient generation of energy by proton exchange membrane fuel cells (PEMFC, using hydrogen as fuel. The generation of hydrogen by the reforming of other fuels, anaerobic fermentation of residual waters and other methods, often produce contaminants that affect the performance of the cell. In this work, the effect of gaseous SO2 and NO2 on the performance of a H2/O2 single PEMFC is studied. The results show that SO2 decreases irreversibly the performance of the cell under operating conditions, while NO2 has a milder effect that allows the recovery of the system.

  17. O estresse salino retarda o desenvolvimento morfofisiológico e a ativação de galactosidases de parede celular em caules de Vigna unguiculata Salt stress delays morphophysiological development and activation of cell wall galactosidases in Vigna unguiculata stems

    Directory of Open Access Journals (Sweden)

    Fabrício Bonfim Sudério

    2011-03-01

    Full Text Available Com o objetivo de examinar o envolvimento das α- e β-galactosidases na expansão celular de caules de plântulas de feijão-de-corda submetidas a estresse salino durante o estabelecimento da plântula, e de analisar os efeitos do estresse salino no desenvolvimento das plântulas e nas atividades enzimáticas, sementes de feijão-de-corda Pitiúba foram semeadas em água destilada e em solução de NaCl 100 mM. Foram coletados caules em diferentes estádios de desenvolvimento e com diferentes tempos após a semeadura. Avaliou-se o crescimento através das medidas de comprimento e das matérias fresca e seca dos caules. A salinidade tanto inibiu como retardou o crescimento dos caules. Os efeitos do NaCl nas atividades galactosidásicas de parede celular foram estudados in vivo e in vitro. A inibição e o retardamento do crescimento dos caules correlacionaram-se com as variações em atividades galactosidásicas. As galactosidases de parede celular de caules de plântulas tiveram suas atividades inibidas com o aumento da concentração de sal no meio de reação. A partir de 250 mM de NaCl as β-galactosidases foram mais sensíveis ao sal que α-galactosidases.In order to examine the participation of α- and β-galactosidases in the cell expansion of stems from cowpea seedlings submitted to salt stress during plant establishment as well as to analyze the effect of salt stress on the development of seedlings and enzymatic activities, Pitiúba cowpea seeds were sown in distilled water and in 100 mM NaCl. Throughout seed germination and seedling development, stems were harvested from seedlings at different stages of development and at different times after planting. Growth was evaluated by measuring stem length and fresh and dry mass of stems. Salinity both inhibited and delayed the growth of seedling stems. The effects of NaCl on galactosidase activities of the cell wall were studied, both in vivo and in vitro. Galactosidase activities in vivo

  18. Kinetic insights over a PEMFC operating on stationary and oscillatory states.

    Science.gov (United States)

    Mota, Andressa; Gonzalez, Ernesto R; Eiswirth, Markus

    2011-12-01

    Kinetic investigations in the oscillatory state have been carried out in order to shed light on the interplay between the complex kinetics exhibited by a proton exchange membrane fuel cell fed with poisoned H(2) (108 ppm of CO) and the other in serie process. The apparent activation energy (E(a)) in the stationary state was investigated in order to clarify the E(a) observed in the oscillatory state. The apparent activation energy in the stationary state, under potentiostatic control, rendered (a) E(a) ≈ 50-60 kJ mol(-1) over 0.8 V < E < 0.6 V and (b) E(a) ≈ 10 kJ mol(-1) at E = 0.3 V. The former is related to the H(2) adsorption in the vacancies of the surface poisoned by CO and the latter is correlated to the process of proton conductivity in the membrane. The dependence of the period-one oscillations on the temperature yielded a genuine Arrhenius dependence with two E(a) values: (a) E(a) around 70 kJ mol(-1), at high temperatures, and (b) E(a) around 10-15 kJ mol(-1), at lower temperatures. The latter E(a) indicates the presence of protonic mass transport coupled to the essential oscillatory mechanism. These insights point in the right direction to predict spatial couplings between anode and cathode as having the highest strength as well as to speculate the most likely candidates to promote spatial inhomogeneities. © 2011 American Chemical Society

  19. Theoretical modeling of structure and function of cathode catalyst layers in PEMFC

    International Nuclear Information System (INIS)

    Wang, Q.; Eikerling, M.; Song, D.; Liu, Z.

    2004-01-01

    'Full text:' In this work, we first investigate transport and reaction kinetics in single agglomerates of cathode catalyst layers in proton exchange fuel cells. Two types of spherical agglomerates are evaluated, which represent limiting structures that can be obtained by distinct synthetic procedures. One type consists of a mixture of carbon/catalyst particles and proton conducting perfluorosulfonated ionomer (PFSI). The other type consists of carbon/catalyst particles and water-filled pores. Performance of the former type is rationalized on the basis of the well-known Thiele-modulus. Characteristics of the latter type are studied using Nernst-Planck and Poisson equations. Aspects of current conversion, reactant and current distributions, and catalyst utilization are explored. In general, the PFSI-filled agglomerates exhibit more homogeneous distributions of reaction rates. Effectiveness factors for them are close to one. However, it was found that proton penetration depths in waterflooded agglomerates could be quite significant as well under certain conditions, resulting in unexpectedly high catalyst utilization. The effects of agglomerate radius and of boundary conditions at the agglomerate surface are studied. Moreover, using the same approach, we evaluate the performance of a flat PFSI-free catalyst layer with water-filled pore space. Compared with conventional composite catalyst layers impregnated with PFSI, the PFSI-free layer exhibits better performance and high Pt utilization for thicknesses less than 0.1 μm. The significance of these results for the optimization catalyst layers in view of operation conditions and synthesis methods is discussed. (author)

  20. Design of flexible polyphenylene proton-conducting membrane for next-generation fuel cells.

    Science.gov (United States)

    Miyake, Junpei; Taki, Ryunosuke; Mochizuki, Takashi; Shimizu, Ryo; Akiyama, Ryo; Uchida, Makoto; Miyatake, Kenji

    2017-10-01

    Proton exchange membrane fuel cells (PEMFCs) are promising devices for clean power generation in automotive, stationary, and portable applications. Perfluorosulfonic acid (PFSA) ionomers (for example, Nafion) have been the benchmark PEMs; however, several problems, including high gas permeability, low thermal stability, high production cost, and environmental incompatibility, limit the widespread dissemination of PEMFCs. It is believed that fluorine-free PEMs can potentially address all of these issues; however, none of these membranes have simultaneously met the criteria for both high performance (for example, proton conductivity) and durability (for example, mechanical and chemical stability). We present a polyphenylene-based PEM (SPP-QP) that fulfills the required properties for fuel cell applications. The newly designed PEM exhibits very high proton conductivity, excellent membrane flexibility, low gas permeability, and extremely high stability, with negligible degradation even under accelerated degradation conditions, which has never been achieved with existing fluorine-free PEMs. The polyphenylene PEM also exhibits reasonably high fuel cell performance, with excellent durability under practical conditions. This new PEM extends the limits of existing fluorine-free proton-conductive materials and will help to realize the next generation of PEMFCs via cost reduction as well as the performance improvement compared to the present PFSA-based PEMFC systems.

  1. High Temperature Polymers for use in Fuel Cells

    Science.gov (United States)

    Peplowski, Katherine M.

    2004-01-01

    NASA Glenn Research Center (GRC) is currently working on polymers for fuel cell and lithium battery applications. The desire for more efficient, higher power density, and a lower environmental impact power sources has led to interest in proton exchanges membrane fuels cells (PEMFC) and lithium batteries. A PEMFC has many advantages as a power source. The fuel cell uses oxygen and hydrogen as reactants. The resulting products are electricity, heat, and water. The PEMFC consists of electrodes with a catalyst, and an electrolyte. The electrolyte is an ion-conducting polymer that transports protons from the anode to the cathode. Typically, a PEMFC is operated at a temperature of about 80 C. There is intense interest in developing a fuel cell membrane that can operate at higher temperatures in the range of 80 C- 120 C. Operating the he1 cell at higher temperatures increases the kinetics of the fuel cell reaction as well as decreasing the susceptibility of the catalyst to be poisoned by impurities. Currently, Nafion made by Dupont is the most widely used polymer membrane in PEMFC. Nafion does not function well above 80 C due to a significant decrease in the conductivity of the membrane from a loss of hydration. In addition to the loss of conductivity at high temperatures, the long term stability and relatively high cost of Nafion have stimulated many researches to find a substitute for Nafion. Lithium ion batteries are popular for use in portable electronic devices, such as laptop computers and mobile phones. The high power density of lithium batteries makes them ideal for the high power demand of today s advanced electronics. NASA is developing a solid polymer electrolyte that can be used for lithium batteries. Solid polymer electrolytes have many advantages over the current gel or liquid based systems that are used currently. Among these advantages are the potential for increased power density and design flexibility. Automobiles, computers, and cell phones require

  2. Biotecnologia e desenvolvimento sustentável

    Directory of Open Access Journals (Sweden)

    Ana Clara Guerrini Schenberg

    2010-01-01

    Full Text Available A biotecnologia pode desempenhar um papel importante para atingir as metas da sustentabilidade. No presente trabalho, são descritos diferentes exemplos bem-sucedidos de micro-organismos especialmente desenhados para otimizar a produção de etanol, a produção de plásticos biodegradáveis a partir de recursos renováveis e a biorremediação de metais tóxicos. Esses processos biotecnológicos contribuem significantemente para promover o desenvolvimento sustentável, embora possam, por enquanto, não ser ainda competitivos em relação às tecnologias convencionais.Biotechnology can play an important role to reach the goals of sustainability. In the present work, we describe successful examples of microorganisms especially designed for optimizing ethanol production, biodegradable plastics production from renewable resources, and toxic metals bioremediation. These biotechnological processes significantly contribute to promote sustainable development, although they may, at present, not be competitive with the conventional technologies.

  3. The Solid-Phase Synthesis of an Fe-N-C Electrocatalyst for High-Power Proton-Exchange Membrane Fuel Cells.

    Science.gov (United States)

    Liu, Qingtao; Liu, Xiaofang; Zheng, Lirong; Shui, Jianglan

    2018-01-26

    The environmentally friendly synthesis of highly active Fe-N-C electrocatalysts for proton-exchange membrane fuel cells (PEMFCs) is desirable but remains challenging. A simple and scalable method is presented to fabricate Fe II -doped ZIF-8, which can be further pyrolyzed into Fe-N-C with 3 wt % of Fe exclusively in Fe-N 4 active moieties. Significantly, this Fe-N-C derived acidic PEMFC exhibits an unprecedented current density of 1.65 A cm -2 at 0.6 V and the highest power density of 1.14 W cm -2 compared with previously reported NPMCs. The excellent PEMFC performance can be attributed to the densely and atomically dispersed Fe-N 4 active moieties on the small and uniform catalyst nanoparticles. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  4. Shock and vibration effects on performance reliability and mechanical integrity of proton exchange membrane fuel cells: A critical review and discussion

    Science.gov (United States)

    Haji Hosseinloo, Ashkan; Ehteshami, Mohsen Mousavi

    2017-10-01

    Performance reliability and mechanical integrity are the main bottlenecks in mass commercialization of PEMFCs for applications with inherent harsh environment such as automotive and aerospace applications. Imparted shock and vibration to the fuel cell in such applications could bring about numerous issues including clamping torque loosening, gas leakage, increased electrical resistance, and structural damage and breakage. Here, we provide a comprehensive review and critique of the literature focusing on the effects of mechanically harsh environment on PEMFCs, and at the end, we suggest two main future directions in FC technology research that need immediate attention: (i) developing a generic and adequately accurate dynamic model of PEMFCs to assess the dynamic response of FC devices, and (ii) designing effective and robust shock and vibration protection systems based on the developed models in (i).

  5. Gram-Scale Synthesis of Highly Active and Durable Octahedral PtNi Nanoparticle Catalysts for Proton Exchange Membrane Fuel Cell

    DEFF Research Database (Denmark)

    Choi, Juhyuk; Jang, Jue-Hyuk; Roh, Chi-Woo

    2018-01-01

    Proton exchange membrane fuel cells (PEMFC) are regarded as a promising renewable energy source for a future hydrogen energy society. However, highly active and durable catalysts are required for the PEMFCs because of their intrinsic high overpotential at the cathode and operation under the acidic...... condition for oxygen reduction reaction (ORR). Since the discovery of the exceptionally high surface activity of Pt3Ni(111), the octahedral PtNi nanoparticles have been synthesized and tested. Nonetheless, their milligram-scale synthesis method and poor durability make them unsuitable...

  6. Mesostructured platinum-free anode and carbon-free cathode catalysts for durable proton exchange membrane fuel cells.

    Science.gov (United States)

    Cui, Xiangzhi; Shi, Jianlin; Wang, Yongxia; Chen, Yu; Zhang, Lingxia; Hua, Zile

    2014-01-01

    As one of the most important clean energy sources, proton exchange membrane fuel cells (PEMFCs) have been a topic of extensive research focus for decades. Unfortunately, several critical technique obstacles, such as the high cost of platinum electrode catalysts, performance degradation due to the CO poisoning of the platinum anode, and carbon corrosion by oxygen in the cathode, have greatly impeded its commercial development. A prototype of a single PEMFC catalyzed by a mesostructured platinum-free WO3/C anode and a mesostructured carbon-free Pt/WC cathode catalysts is reported herein. The prototype cell exhibited 93% power output of a standard PEMFC using commercial Pt/C catalysts at 50 and 70 °C, and more importantly, CO poisoning-free and carbon corrosion-resistant characters of the anode and cathode, respectively. Consequently, the prototype cell demonstrated considerably enhanced cell operation durability. The mesostructured electrode catalysts are therefore highly promising in the future development and application of PEMFCs. Copyright © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  7. Investigating the effects of methanol-water vapor mixture on a PBI-based high temperature PEM fuel cell

    DEFF Research Database (Denmark)

    Araya, Samuel Simon; Andreasen, Søren Juhl; Nielsen, Heidi Venstrup

    2012-01-01

    This paper investigates the effects of methanol and water vapor on the performance of a high temperature proton exchange membrane fuel cell (HT-PEMFC). A H3PO4-doped polybenzimidazole (PBI) membrane electrode assembly (MEA), Celtec P2100 of 45 cm2 of active surface area from BASF was employed...

  8. EIS Characterization of the Poisoning Effects of CO and CO2 on a PBI based HT-PEM Fuel Cell

    DEFF Research Database (Denmark)

    Andreasen, Søren Juhl; Mosbæk, Rasmus; Vang, Jakob Rabjerg

    2010-01-01

    This paper presents test results regarding the poisoning effects of CO and CO2 on H3PO4/Polybenzimidazole (PBI) membrane based high temperature proton exchange membrane fuel cell (HT-PEMFC). Electrochemical impedance spectroscopy (EIS), which is a non intrusive diagnostic tool for electrochemical...

  9. Lowering the platinum loading of high temperature polymer electrolyte membrane fuel cells with acid doped polybenzimidazole membranes

    DEFF Research Database (Denmark)

    Fernandez, Santiago Martin; Li, Qingfeng; Jensen, Jens Oluf

    2015-01-01

    Membrane electrode assemblies (MEAs) with ultra-low Pt loading electrodes were prepared for high temperature polymer electrolyte membrane fuel cells (HT-PEMFCs) based on acid doped polybenzimidazole. With no electrode binders or ionomers, the triple phase boundary of the catalyst layer was establ...

  10. Dynamic characteristics of an automotive fuel cell system for transitory load changes

    OpenAIRE

    Rabbani, Raja Abid; Rokni, Masoud

    2013-01-01

    A dynamic model of Polymer Electrolyte Membrane Fuel Cell (PEMFC) system is developed to investigate the behavior and transient response of a fuel cell system for automotive applications. Fuel cell dynamics are subjected to reactant flows, heat management and water transportation inside the fuel cell. Therefore, a control-oriented model has been devised in Aspen Plus Dynamics, which accommodates electrochemical, thermal, feed flow and water crossover models in addition to two-phase calculatio...

  11. MEA degradation in PEM Fuel Cell : a joint SEM and TEM study

    OpenAIRE

    Silva, R. A.; Hashimoto, T.; Thompson, G. E.; Rangel, C. M.

    2011-01-01

    One of the important factors determining the lifetime of polymer electrolyte membrane fuel cells (PEMFCs) is membrane electrode assembly (MEA) degradation and failure. The lack of effective mitigation methods is largely due to the currently very limited understanding of the underlying mechanisms for mechanical and chemical degradations of fuel cell MEAs. This work reports on the effect of 1500 h operation of an eight-cell stack Portuguese prototype low power fuel cell. A performance decrease ...

  12. Gerenciamento de Projetos em Pesquisa e Desenvolvimento

    Directory of Open Access Journals (Sweden)

    Mauro Maia Laruccia

    2013-01-01

    Full Text Available Este trabalho tem por objetivo estudar o gerenciamento de projetos na área de Pesquisa e Desenvolvimento, em um cenário onde os avanços da tecnologia têm influenciado nas mais diversas áreas do conhecimento humano e passaram a exigir abordagens diferenciadas na forma de planejar, executar e controlar os projetos, para assegurar os resultados almejados pelas organizações. Avaliar as formas de conhecimento aplicadas ao gerenciamento de projetos e as interações de suas disciplinas apresenta-se como uma condição oportuna para compreensão e melhoria do processo de gerenciamento de projetos. Considerando que a interdisciplinaridade destaca-se na crítica e na busca de respostas aos limites do conhecimento e que rompe com o paradigma disciplinar de produção do conhecimento particionado, a análise da forma de conhecimento do gerenciamento de projetos pode contribuir para desvelar oportunidades e engendrar melhorias neste processo. Verifica-se que o gerenciamento de projeto tem evoluído continuamente e congrega diversas disciplinas do conhecimento nos modelos praticados. Atualmente, um dos modelos mais consagrados de gerenciamento de projetos é o Project Management Body of Knowledge (PMBOK, publicado pelo Project Management Institute (PMI, que é utilizado em mais de 185 países. Vale ressaltar, que a simples comunicação entre as disciplinas do gerenciamento de projetos não significa que estejamos aplicando necessariamente uma abordagem interdisciplinar. Analisar o gerenciamento de projetos na ótica da interdisciplinaridade pode contribuir para o aperfeiçoamento dos modelos de gerenciamento de projetos e consequentemente para a geração de melhores resultados para as organizações.DOI:10.5585/gep.v3i3.82

  13. Development of solar cells with back surface field made by aluminum paste and belt furnace diffusion; Desenvolvimento de celulas solares com campo retrodifusor formado por pasta de aluminio e difusao em forno de esteira

    Energy Technology Data Exchange (ETDEWEB)

    Marcolino, Juliane Bernardes

    2011-01-15

    Photovoltaics is based on the direct conversion of solar energy into electricity and is a promising alternative to diversify the world's energy matrix. This work aims to develop and analyse the deposition of Al paste by screen printing and firing/diffusion in a belt furnace to produce a BSF region in monocrystalline Si wafers. The diffusion of Al into the substrate was implemented by two different processes. In the first process the diffusion/firing of the Al paste and the firing of the Ag paste was carried out in independent steps. In this case, solar cells with an average efficiency ({eta}{sub average}) of 11.5 % and a maximum of 12.0 % were produced, but with the formation Al clusters in the back surface of the devices. In the second process firing/diffusion of such pastes was done on the same step. In this case, the best results were obtained for a firing/diffusion temperature of 860 deg C and belt furnace speed (V{sub E}) of 150 cm/min and also for 890 deg C and 180 cm/min. For the former parameters, {eta}{sub average} was 12.4 % and the maximum was 12.8 %. For the later, {eta}{sub average} was 12.5 % and the maximum was 12.6 %. Considering a temperature of 900 deg C and V{sub E} of 190 cm/min, {eta}{sub average} was 12.4 %. It was observed that minority carriers diffusion lengths were smaller than the thickness of silicon wafers. Open circuit voltages were 30 mV lower than that from similar cells fabricated at NT-Solar by using high purity Al deposited by e-beam evaporation indicating that the developed process produced low quality BSF. (author)

  14. Sliding-Mode Control of PEM Fuel Cells

    CERN Document Server

    Kunusch, Cristian; Mayosky, Miguel

    2012-01-01

    Recent advances in catalysis technologies and new materials make fuel cells an economically appealing and clean energy source with massive market potential in portable devices, home power generation and the automotive industry. Among the more promising fuel-cell technologies are proton exchange membrane fuel cells (PEMFCs). Sliding-Mode Control of PEM Fuel Cells demonstrates the application of higher-order sliding-mode control to PEMFC dynamics. Fuel-cell dynamics are often highly nonlinear and the text shows the advantages of sliding modes in terms of robustness to external disturbance, modelling error and system-parametric disturbance using higher-order control to reduce chattering. Divided into two parts, the book first introduces the theory of fuel cells and sliding-mode control. It begins by contextualising PEMFCs both in terms of their development and within the hydrogen economy and today’s energy production situation as a whole. The reader is then guided through a discussion of fuel-cell operation pr...

  15. HANARO Neutron Radiography Facility and Fuel Cell Research

    International Nuclear Information System (INIS)

    Kim, Taejoo

    2013-01-01

    Fuel cell which generates electric energy from hydrogen and oxygen is one of noticed renewable energy system because this has high efficiency and free from CO 2 . Especially, PEMFC (Polymer Electrolyte Membrane Fuel Cell) is focused by automotive companies because PEMFC, which has high power rate per volume and low operating temperature (60∼80), is suited due to the compact design and short start-up time. The water management is one of the most critical issues for fuel cell commercialization. In order to make a proper scheme for water management, thein formation of water distribution and behavior is very important. Neutron imaging is the best method to visualize the water at fuel cell and has been applied worldwide with qualitative and quantitative results. Because the NRF has large beam size (350Χ450mm 2 ) and relatively high neutron flux (2Χ107 n/cm 2 sec), it is suitable for large scale fuel cell research. Neutron imaging technique was used to investigate the water distribution and behavior in PEMFC under different operating conditions. The NRF has contributed the improvement of fuel cell performance and is one of the best choices for fuel cell study

  16. Characterizing automotive fuel cell materials by soft x-ray scanning transmission x-ray microscopy

    International Nuclear Information System (INIS)

    Hitchcock, A. P.; Lee, V.; Wu, J.; Cooper, G.; West, M. M.; Berejnov, V.; Soboleva, T.; Susac, D.; Stumper, J.

    2016-01-01

    Proton-Exchange Membrane Fuel Cell (PEM-FC) based engines are being developed rapidly for near-term implementation in hydrogen fueled, mass production, personal automobiles. Research is focused on understanding and controlling various degradation processes (carbon corrosion, Pt migration, cold start), and reducing cost by reducing or eliminating Pt catalyst. We are using soft X-ray scanning transmission X-ray microscopy (STXM) at the S 2p, C 1s, O 1s and F 1s edges to study a variety of issues related to optimization of PEM-FC materials for automotive applications. A method to efficiently and accurately measure perfluorosulfonic acid distributions was developed and is being used to better understand how different loadings and preparation methods affect the ionomer distribution in the cathode. Progress towards an environmental cell capable of controlling the temperature and humidity of a PEM-FC sample in the STXM is described. Methods for studying the 3D chemical structure of PEM-FC are outlined

  17. Energy analysis of fuel cell system for commercial greenhouse application – A feasibility study

    International Nuclear Information System (INIS)

    Vadiee, Amir; Yaghoubi, Mahmoud; Sardella, Marco; Farjam, Pardis

    2015-01-01

    Highlights: • Feasibility study of integrating a PEMFC with a commercial greenhouse. • An energy analysis has been performed in order to evaluate the energetic performance of the system. • A sensitivity analysis on the main influencing operating parameters for optimization. - Abstract: The purpose of this paper is to investigate the feasibility of integrating a proton exchange membrane fuel cell (PEMFC) system with a commercial greenhouse and assess the mutual benefits of such integration. The main objective is to recover the low quality waste heat of the PEMFC system in order to meet the thermal energy demand of a commercial greenhouse. In addition the PEMFC covers the some part of the greenhouse electrical demand. In this study an energy analysis has been performed in order to evaluate the energetic performance of the system. To achieve these aims, first, a system model has been developed using TRNSYS. Afterwards, a sensitivity analysis has been carried out varying the main influencing operating parameters in order to evaluate an optimal configuration of the system. In particular the influences of temperature and air stoichiometry have been investigated. The results show that a 3 kW fuel cell system is capable to cover approximately the 25% and 10% of the usual electricity and heat demands of a 1000 m 2 commercial greenhouse during a year, respectively

  18. Development and characterization of proton conductive membranes and membrane electrode assemblies for fuel cells

    Science.gov (United States)

    Jiang, Ruichun

    Polymer electrolyte membrane fuel cells (PEMFCs), including hydrogen fuel cells (PEMFCs) and direct methanol fuel cells (DMFCs), are considered as attractive electrical power sources. However, there are some technical obstacles that impede the commercialization of PEMFCs. For instance, in H 2-PEMFCs, carbon monoxide (CO) poisoning of the anode catalyst causes serious performance loss; in DMFCs, methanol crossover through the membrane reduces the overall fuel cell efficiency. This work focused on: (1) developing high performance membrane electrode assemblies (MEAs) and investigating their behavior at higher temperature H2-PEMFC with H2+CO as the fuel; (2) improving DMFCs efficiency by preparing low methanol crossover/good proton conductivity membranes based on NafionRTM matrix; (3) synthesizing and modifying low cost sulfonated hydrocarbon (SPEEK) membranes for both H2-PEMFCs and DMFCs applications. High performance membrane electrode assemblies (MEAs) with composite NafionRTM-TeflonRTM-Zr(HPO 4)2 membranes were prepared, optimized and characterized at higher temperature (> 100°C)/lower relative humidity (oxidation mechanism of H2/CO in higher temperature PEMFC was investigated and simulated. Two type of membranes based on NafionRTM matrix were prepared: silica/NafionRTM membrane and palladium impregnated NafionRTM (Pd-NafionRTM) membrane. The composite silica/NafionRTM membrane was developed by in-situ sol-gel reaction followed by solution casting, while the Pd-NafionRTM was fabricated via a supercritical fluid CO2 (scCO 2) route. Reduced methanol crossover and enhanced efficiency was observed by applying each of the two membranes to DMFCs. In addition, the research demonstrated that scCO2 is a promising technique for modifying membranes or depositing nano-particle electrocatalysts onto electrolyte. Sulfonated poly(ether ether ketone) (SPEEK) was synthesized by a sulfonation reaction using poly(ether ether ketone) (PEEK). Multilayer structure SPEEK membranes with

  19. Synthesis and characterization of RUM catalysts (M=SE,MO,W,SN) applied in ORR for a PEMFC fuel battery; Sintesis y caracterizacion de catalizadores RUM (M=SE,MO,W,SN) aplicados en la RRO para una pila de combustible PEMFC

    Energy Technology Data Exchange (ETDEWEB)

    Ezeta-Mejia, A.; Arce Estrada, E.M. [Instituto Politecnico Nacional, Mexico, D.F. (Mexico)]. E-mail: araceli-ezeta@hotmail.com; earce@ipn.mx

    2009-09-15

    Proton exchange membrane fuel cells (PEMFC) have received a great deal of interest recently because of a variety of factors, such as low weight and volume, operating at low temperatures and offering a high combination of power density and high efficiency in the conversion of energy, making them adequate for portable applications. Nevertheless, oxygen reduction reaction (ORR) occurring in the cathode of the battery plays a determinant role as the limiting reaction. Therefore, more efficient electrocatalysts need to be used. The optimal electrocatalyst for this reaction is Pt, but because of its high cost, alternative low-cost electrocatalysts with high activity and stability have been sought. Many investigations have shown that the Pt-based binary catalysts, such as Pt-M (M= Co, Fe, etc.) present good electrocatalytic activity for ORR; other studies show that Ru-based catalysts (RuSe, RuSe,Mo, RuSeRh ) also have adequate activity for this reaction. This study reports on synthesis by mechanical alloying of RuPt{sub x}M (x=0, 0.6% and M=Se,Mo,W,Sn) electrocatalyst nanoparticles at different grinding durations (0, 20 and 40 h). The materials synthesized by mechanical alloying were characterized using sweep electron microscopy and x-ray diffraction, obtaining agglomerated and dispersed particles between 1 and 30 {mu}m. The electrocatalytic characterization was conducted using VC and EDR techniques in H{sub 2}SO{sub 4} 0.5 M solution at ambient temperatures. The systems present a reaction order of 1 with respect to ORR and an overall multi-electron transfer of 4e{sup -} for the formation of water. A comparison was made between the electrocatalytic activity in the presence and absence of Pt, showing that Pt increases the catalytic activity of the materials by at least 1 order of magnitude. [Spanish] Las pilas de combustible de Membrana de Intercambio Protonico (PEMFC) han recibido gran interes recientemente por diversos factores tales como su bajo peso y volumen, operan a

  20. Modeling two-phase flow in three-dimensional complex flow-fields of proton exchange membrane fuel cells

    Science.gov (United States)

    Kim, Jinyong; Luo, Gang; Wang, Chao-Yang

    2017-10-01

    3D fine-mesh flow-fields recently developed by Toyota Mirai improved water management and mass transport in proton exchange membrane (PEM) fuel cell stacks, suggesting their potential value for robust and high-power PEM fuel cell stack performance. In such complex flow-fields, Forchheimer's inertial effect is dominant at high current density. In this work, a two-phase flow model of 3D complex flow-fields of PEMFCs is developed by accounting for Forchheimer's inertial effect, for the first time, to elucidate the underlying mechanism of liquid water behavior and mass transport inside 3D complex flow-fields and their adjacent gas diffusion layers (GDL). It is found that Forchheimer's inertial effect enhances liquid water removal from flow-fields and adds additional flow resistance around baffles, which improves interfacial liquid water and mass transport. As a result, substantial improvements in high current density cell performance and operational stability are expected in PEMFCs with 3D complex flow-fields, compared to PEMFCs with conventional flow-fields. Higher current density operation required to further reduce PEMFC stack cost per kW in the future will necessitate optimizing complex flow-field designs using the present model, in order to efficiently remove a large amount of product water and hence minimize the mass transport voltage loss.

  1. DEVELOPMENT OF NOVEL ELECTROCATALYSTS FOR PROTON EXCHANGE MEMBRANE FUEL CELLS

    Energy Technology Data Exchange (ETDEWEB)

    Shamsuddin Ilias

    2003-04-24

    Fuel cells are electrochemical devices that convert the available chemical free energy directly into electrical energy, without going through heat exchange process. Of all different types of fuel cells, the Proton Exchange Membrane Fuel Cell (PEMFC) is one of the most promising power sources for stand-alone utility and electric vehicle applications. Platinum (Pt) Catalyst is used for both fuel and air electrodes in PEMFCs. However, carbon monoxide (CO) contamination of H{sub 2} greatly affects electro catalysts used at the anode of PEMFCs and decreases cell performance. The irreversible poisoning of the anode can occur even in CO concentrations as low as few parts per million (ppm). In this work, we have synthesized several novel elctrocatalysts (Pt/C, Pt/Ru/C, Pt/Mo/C, Pt/Ir and Pt/Ru/Mo) for PEMFCs. These catalysts have been tested for CO tolerance in the H{sub 2}/air fuel cell, using CO concentrations in the H{sub 2} fuel that varies from 10 to 100 ppm. The performance of the electrodes was evaluated by determining the cell potential against current density. The effects of catalyst composition and electrode film preparation method on the performance of PEM fuel cell were also studied. It was found that at 70 C and 3.5 atm pressure at the cathode, Pt-alloy catalyst (10 wt% Pt/Ru/C, 20 wt% Pt/Mo/C) were more CO tolerant than the 20 wt% Pt/C catalyst alone. It was also observed that spraying method was better than the brushing technique for the preparation of electrode film.

  2. Experimental study on the self-humidification effect in proton exchange membrane fuel cells containing double gas diffusion backing layer

    International Nuclear Information System (INIS)

    Kong, Im Mo; Choi, Jong Won; Kim, Sung Il; Lee, Eun Sook; Kim, Min Soo

    2015-01-01

    Highlights: • Investigated self-humidification effect of structurally modified GDBLs in PEMFCs. • One conventional and two modified GDLs were prepared. • Structural design of the GDBLs significantly affected self-humidification. • Stacking was found to have negligible effect on self-humidification. • It can be applied readily to self-humidified PEMFCs. - Abstract: Adequate hydration of the membrane is required to ensure high proton conductivity in proton exchange membrane fuel cells (PEMFCs), which, in turn, is required for achieving high cell performances. While external humidifiers are typically used to humidify the supplied air in conventional systems, their use increases the complexity, weight, volume, and parasitic power loss in fuel cell systems, rendering them unviable in some systems, particularly for portable applications. In this study, the structure of a gas diffusion backing layer (GDBL) was modified to enhance the self-humidification effect in PEMFCs. Three types of GDLs were prepared for the experiments: a conventional GDL (GDL-A with uniform single GDBL) and two modified GDLs (GDL-A′B with uniform double GDBL and GDL-A′C with heterogeneous double GDBLs). In order to evaluate the effect of stacking and structural design on the self-humidification characteristics, some characteristics of the GDLs such as contact angle, resistance, and vapor permeation rate were measured. The electrochemical performances of the fuel cells were also measured at various relative humidity (RH) and stoichiometric ratio (SR) conditions. The results showed that stacking had a negligible effect, whereas the structural design of the GDBL had a significant effect on self-humidification. The self-humidification effect and the cell performance were improved significantly in the structurally modified GDBL. In addition, considering the actual field conditions and the results of the present study, it was concluded that the structural modifications made to the GDBL would

  3. Desenvolvimento de capacidades e gestualidade espontânea

    Directory of Open Access Journals (Sweden)

    Andrea de Arruda Botelho-Borges

    2011-08-01

    Full Text Available O objetivo deste artigo é apresentar e discutir, em uma interlocução com o pensamento winnicottiano, a potencialidade mutativa de uma modalidade de prática psicológica denominada Enquadre Clínico para Desenvolvimento de Capacidades; propõe, ainda, uma elaboração conceitual que distingue capacidades integradas e competências dissociadas. À luz de tal distinção, essa alternativa clínica pode ser compreendida como constituição de um ambiente facilitador que favorece tanto o desenvolvimento de capacidades incipientes como a integração de competências dissociadas, que passam a ser vividas transicionalmente como experiências criativas. Esse enquadre vem sendo utilizado produtivamente na forma de uma oficina voltada ao desenvolvimento da capacidade de escrever.

  4. Preparando um ambiente de desenvolvimento para a plataforma android

    Directory of Open Access Journals (Sweden)

    Felipe Pires de Oliveira

    2015-12-01

    Full Text Available Este artigo descreve as etapas para a criação de um ambiente de desenvolvimento para a plataforma Android. O artigo foi dividido em quatro partes: Primeiro uma introdução sobre o assunto. Na segunda seção são mostrados os passos necessários para a configuração do ambiente de desenvolvimento. Na terceira seção, é demonstrado como criar uma aplicação para dispositivo Android que calculo Índice de Massa Corporal (IMC. A quarta seção apresenta as considerações finais. A solução abordada tem como base a IDE Eclipse e o SDK do Android, bem como o Kit de Desenvolvimento Java da Oracle (JDK.

  5. Preparando um ambiente de desenvolvimento para a plataforma android

    Directory of Open Access Journals (Sweden)

    Felipe Pires de Oliveira

    2015-11-01

    Full Text Available Este artigo descreve as etapas para a criação de um ambiente de desenvolvimento para a plataforma Android. O artigo foi dividido em quatro partes: Primeiro uma introdução sobre o assunto. Na segunda seção são mostrados os passos necessários para a configuração do ambiente de desenvolvimento. Na terceira seção, é demonstrado como criar uma aplicação para dispositivo Android que calculo Índice de Massa Corporal (IMC. A quarta seção apresenta as considerações finais. A solução abordada tem como base a IDE Eclipse e o SDK do Android, bem como o Kit de Desenvolvimento Java da Oracle (JDK.

  6. Os eventos programados, como alternativo do desenvolvimento do turismo

    Directory of Open Access Journals (Sweden)

    Andrés Pinassi

    2014-10-01

    Full Text Available Turismo e lazer são vistos como uma alternativa para o desenvolvimento econômico, social e cultural de uma comunidade. Ambas práticas de lazer são consolidadas como processos sócio-espaciais que podem trazer muitos impactos benéficos para os moradores de uma determinada localidade. Assim, a dinâmica de eventos programados em aldeias visa proporcionar uma alternativa oportunidades de desenvolvimento local para comunidades carentes. Nesse contexto, a pesquisa desenvolvida, em seguida, analisa o desenvolvimento de um festival especial, realizada na Provincia de Buenos Aires (Argentina. Este festival, iniciado a partir da esfera pública municipal, mostrou benefícios económicos significativos e definir um entretenimento alternativa valiosa para a população local e da área de influência.

  7. Direct observation of the dealloying process of a platinum–yttrium nanoparticle fuel cell cathode and its oxygenated species during the oxygen reduction reaction

    DEFF Research Database (Denmark)

    Malacrida, Paolo; Sanchez Casalongue, Hernan G.; Masini, Federico

    2015-01-01

    Size-selected 9 nm PtxY nanoparticles have recently shown an outstanding catalytic activity for the oxygen reduction reaction, representing a promising cathode catalyst for proton exchange membrane fuel cells (PEMFCs). Studying their electrochemical dealloying is a fundamental step towards the nd...

  8. Constant Power Control of a Proton Exchange Membrane Fuel Cell through Adaptive Fuzzy Sliding Mode

    OpenAIRE

    Minxiu Yan; Liping Fan

    2013-01-01

    Fuel cell is a device that converts the chemical energy from a fuel into electricity through a chemical reaction with oxygen or another oxidizing agent. The paper describes a mathematical model of proton exchange membrane fuel cells by analyzing the working mechanism of the proton exchange membrane fuel cell. Furthermore, an adaptive fuzzy sliding mode controller is designed for the constant power output of PEMFC system. Simulation results prove that adaptive fuzzy sliding mode control has be...

  9. Characterization of transport phenomena in small polymer electrolyte membrane fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Himanen, O.P.

    2008-07-01

    In small fuel cell systems, energy consumption and size of auxiliary devices should be minimized. One option is to use passive controlling methods that rely on material and structural solutions. Therefore it is important to understand transport phenomena occurring in the cells. In this thesis, charge, mass, and heat transport phenomena related to small PEMFCs were studied experimentally and by modeling. A new method was developed for the characterization of water transport properties of polymer electrolyte membrane under realistic operating conditions. The method was used to evaluate the diffusion coefficient of water in the membrane. Due to channelrib structure, cell components are inhomogeneously compressed. Charge and mass transport parameters were experimentally evaluated as a function of compression. The effect of inhomogeneous compression on cell operation was studied by modeling. Inhomogeneous compression does not significantly affect the polarization behavior of the cell, but it creates uneven current and temperature distributions inside the cell. This affects both cell performance and lifetime and should not be ignored in cell design and modeling. The operation of a freebreathing PEMFC was studied at subzero temperatures. To be able to operate at low temperatures, current density must be high enough to avoid freezing of reactant product water inside the cell. Startup at cold temperatures requires active heating. To maximize fuel efficiency, the operation of a freebreathing PEMFC in dead end mode was investigated. Dead ended operation with periodic purging enables high fuel utilization rate and the test cell operated without significant water management problems or performance loss. (orig.)

  10. DESENVOLVIMENTO REGIONAL E URBANO: EFICIÊNCIA, SUSTENTABILIDADE E FINANCIAMENTO

    OpenAIRE

    João Serafim Tusi Da Silveira; Rozelaine de Fátima Franzin; Attus Pereira Moreira; Lucas Veiga Ávila; Lúcia Rejane da Rosa Gama Madruga; Rut Maria Friedrich Marquetto

    2014-01-01

    No financiamento de políticas de desenvolvimento regional no Brasil, o papel do Estado é imprescindível, ainda que tenha beneficiado elites locais e deixado regiões estagnadas. Esses efeitos podem ser atenuados com políticas em que os novos créditos dependam dos objetivos a serem alcançados. Neste artigo, a investigação desta premissa fundamenta-se na dinâmica do desenvolvimento socioeconômico sustentável de Celso Furtado. Para sua verificação, estimou-se um modelo de fronteira estocástica de...

  11. Business coaching na actualidade: desenvolvimento e importância

    OpenAIRE

    Parra, Alicia Neto

    2012-01-01

    Relatório de Dissertação de Mestrado em Gestão / JEL: M12 – Personnel Management; Executive Compensation M53 – Training A expansão do coaching no mundo empresarial é uma realidade ascendente. A forte aposta no desenvolvimento dos colaboradores contribui largamente para o sucesso nas organizações, sendo uma mais-valia para ambos. O objectivo desta pesquisa é explorar a importância do coaching no ambiente empresarial actual e compreender o seu desenvolvimento. Assim, todo o processo será...

  12. Ensaio sobre desenvolvimento humano na pós-modernidade

    OpenAIRE

    Abib,José Antônio Damásio

    2008-01-01

    Neste ensaio, o conceito de desenvolvimento humano na pós-modernidade apóia-se em uma filosofia pós-moderna de direitos humanos, e na modernidade apóia-se em uma filosofia moderna de direitos humanos. O Estado moderno fracassou na realização da filosofia moderna dos direitos humanos. Uma filosofia pós-moderna de direitos humanos deixa para trás a filosofia moderna de direitos humanos. Isso significa abandonar o fundacionismo ético e as grandes narrativas emancipatórias de desenvolvimento huma...

  13. O JOGO TEATRAL COMO ALIADO DO DESENVOLVIMENTO PSICOMOTOR INFANTIL

    OpenAIRE

    Pinheiro, Lucas

    2016-01-01

    O presente artigo tem por pressuposto apresentar as possíveis influências que os Jogos Teatrais oferecem ao desenvolvimento psicomotor de crianças em idade pré-escolar, ou seja, aquelas com menos de seis anos de idade. Os aspectos abrangidos neste contexto vão desde a definição do conceito de psicomotricidade até a importância que o jogo teatral – e logo da ludicidade – tem para o desenvolvimento do ser humano, e, neste caso em específico, das crianças.

  14. Polybenzimidazoles based on high temperature polymer electrolyte fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Linares Leon, Jose Joaquin; Camargo, Ana Paula M.; Ashino, Natalia M.; Morgado, Daniella L.; Frollini, Elisabeth; Paganin, Valdecir A.; Gonzalez, Ernesto Rafael [Universidade de Sao Paulo (IQSC/USP), Sao Carlos, SP (Brazil); Bajo, Justo Lobato [University of Castilla-La Mancha, Ciudad Real (Spain). Dept. of Chemical Engineering

    2010-07-01

    This work presents an interesting approach in order to enhance the performance of Polymer Electrolyte Membrane Fuel Cells (PEMFC) by means of an increase in the operational temperature. For this, two polymeric materials, Poly(2,5-bibenzimidazole) (ABPBI) and Poly[2,2'-(m-phenyl en)-5,5' bib enzimidazol] (PBI), impregnated with phosphoric acid have been utilized. These have shown excellent properties, such as thermal stability above 500 deg C, reasonably high conductivity when impregnated with H{sub 3}PO{sub 4} and a low permeability to alcohols compared to Nafion. Preliminary fuel cells measurements on hydrogen based Polymer Electrolyte Membrane Fuel Cell (PEMFC) displayed an interestingly reasonable good fuel cell performance, a quite reduced loss when the hydrogen stream was polluted with carbon monoxide, and finally, when the system was tested with an ethanol/water (E/W) fuel, it displayed quite promising results that allows placing this system as an attractive option in order to increase the cell performance and deal with the typical limitations of low temperature Nafion-based PEMFC. (author)

  15. Experimental Investigation and Discussion on the Mechanical Endurance Limit of Nafion Membrane Used in Proton Exchange Membrane Fuel Cell

    Directory of Open Access Journals (Sweden)

    Yang Xiao

    2014-10-01

    Full Text Available As a solution of high efficiency and clean energy, fuel cell technologies, especially proton exchange membrane fuel cell (PEMFC, have caught extensive attention. However, after decades of development, the performances of PEMFCs are far from achieving the target from the Department of Energy (DOE. Thus, further understanding of the degradation mechanism is needed to overcome this obstacle. Due to the importance of proton exchange membrane in a PEMFC, the degradation of the membrane, such as hygrothermal aging effect on its properties, are particularly necessary. In this work, a thick membrane (Nafion N117, which is always used as an ionic polymer for the PEMFCs, has been analyzed. Experimental investigation is performed for understanding the mechanical endurance of the bare membranes under different loading conditions. Tensile tests are conducted to compare the mechanical property evolution of two kinds of bare-membrane specimens including the dog-bone and the deeply double edge notched (DDEN types. Both dog-bone and DDEN specimens were subjected to a series of degradation tests with different cycling times and wide humidity ranges. The tensile tests are repeated for both kinds of specimens to assess the strain-stress relations. Furthermore, Fourier transform infrared spectroscopy (FT-IR, X-ray diffraction (XRD and Scanning electron microscope (SEM observation and water absorption measurement were conducted to speculate the cause of this variation. The initial cracks along with the increasing of bound water content were speculated as the primary cause.

  16. Influência do substrato e do tamanho da célula de bandejas de poliestireno expandido no desenvolvimento de mudas e produção de calêndula (Calendula officinalis L. Influence of substrate and cell size of expanded polystyrene tray on the development and production of marigold (Calendula officinalis L. seedlings

    Directory of Open Access Journals (Sweden)

    C.K.R Barbosa

    2010-03-01

    Full Text Available A calêndula (Calendula officinalis L. é uma planta medicinal anual de origem Mediterrânica que apresenta propriedades antiinflamatórias, antivirais, antigenotóxicas. A propagação desta planta normalmente é feita por sementes, sendo o uso de bandejas de poliestireno uma forma econômica de produção de mudas. Foram conduzidos dois experimentos com o objetivo de avaliar a interferência de dois tamanhos de célula em bandeja de poliestireno expandido (40 cm³ e 12 cm³ e de dois substratos (solo + esterco bovino curtido e substrato comercial tipo Plantmax para hortaliças® sobre a qualidade de mudas e a produção de calêndula. O delineamento estatístico nos dois experimentos foi em blocos casualizados, dispostos em arranjo fatorial 2 x 2 (dois substratos e dois tamanhos de células com seis repetições. Os tratamentos, referentes aos tamanhos das células foram bandeja com 128 células (40 cm³ de volume e, bandeja com 288 células (12 cm³ de volume. Os substratos utilizados foram solo de cerrado + esterco bovino curtido (1:1 e substrato comercial tipo "Plantmax para hortaliças®". Parte das mudas foi transplantada para avaliação da produção de capítulos. Houve diferenças significativas entre os substratos para as variáveis: matéria seca de parte aérea, matéria seca da raiz e matéria seca total. O uso do substrato formulado com solo de cerrado e esterco bovino proporcionou o melhor desenvolvimento das mudas de calêndula. Contudo, os diferentes tipos de substrato e bandejas de poliestireno não influenciaram significativamente a produção de capítulos das mudas transplantadas.Marigold Calendula (Calendula officinalis L. is an annual medicinal plant of Mediterranean origin which presents anti-inflammatory, antiviral and antigenotoxic properties. This species normally propagates through seeds, and the use of polystyrene trays is an economic way to produce its seedlings. Two experiments were carried out to evaluate the

  17. Effect of L-Arginine and L-NAME treatments on polymorphonuclear leukocytes and mononuclear cells influx during tumor growth Efeito dos tratamentos com L-Arginina e L-NAME sobre o influxo de leucócitos polimorfonucleares e células mononucleares durante o desenvolvimento tumoral

    Directory of Open Access Journals (Sweden)

    Olívia Teixeira Gomes Reis

    2009-04-01

    Full Text Available PURPOSE: Evaluate polymorphonuclear leukocytes (PMN's and mononuclear cells (MN's involvement in the Ehrlich´s solid tumor (ET growth. METHODS: 90 Swiss mice were inoculated with 10(7 tumor cells (sc, distributed in three groups and treated once a day, via intraperitoneal (ip, with 0.1ml of diluent, L-Arginine (20mg/Kg or L-NAME (20mg/Kg. After 7, 15 and 30 days of treatment, ten animals of each group were euthanized, the tumor mass was removed, processed and fixed for HE. Later, a morphometric analysis of the total area, parenchyma, necrosis, tumor stroma and PMN's leukocytes and MN's cells influx was performed. RESULTS: The L-Arginine treatment increased PMN's influx in the initial stage, whereas L-NAME reduced it. Our data suggests that NO effect on PMN's migration is dose-dependent. On the other hand, the MN´s cells influx was reduced by L-NAME treatment at all evaluated periods and at the same periods an increase in tumor growth was observed. CONCLUSION: At initial stages of tumor implantation, both PMN's leukocytes and MN's cells act together to control ET development.OBJETIVO: Avaliar o envolvimento de leucócitos polimorfonucleares (PMN's e células mononucleares (MN's no crescimento do Tumor Sólido de Ehrlich (TE. MÉTODOS: 90 camundongos Suíços foram inoculados com 10(7 células tumorais (sc, distribuídos em três grupos e tratados uma vez ao dia, via intraperitoneal (ip, com 0.1ml de diluente, L-Arginina (20mg/Kg ou L-NAME (20mg/Kg. Após 7, 15 e 30 dias, dez animais de cada grupo foram eutanasiados, a massa tumoral foi removida, processada e corada pela HE. Posteriormente, foi realizada análise morfométrica das áreas total, parênquima, necrose, estroma e influxo de leucócitos PMN's e células MN's. RESULTADOS: O tratamento com L-Arginina favoreceu o influxo de PMN's em períodos iniciais, enquanto o tratamento com L-NAME o reduziu. Nosso estudo sugere que o efeito do ON sobre a migração de PMN's é dose-dependente. Por

  18. DEVELOPMENT OF NOVEL ELECTROCATALYSTS FOR PROTON EXCHANGE MEMBRANE FUEL CELLS

    Energy Technology Data Exchange (ETDEWEB)

    Shamsuddin Ilias

    2001-07-06

    Proton Exchange Membrane Fuel Cell (PEMFC) is one of the most promising power sources for space and electric vehicle applications. Platinum (Pt) catalyst is used for both fuel and air electrodes in PEMFCs. The carbon monoxide (CO) contamination of H{sub 2} greatly affects electrocatalysts used at the anode of PEMFCs and decrease the cell performance. This irreversible poisoning of the anode can happen even in CO concentrations as low as few ppm, and therefore, require expensive scrubbing of the H{sub 2}-fuel to reduce the contaminant concentration to acceptable level. In order to commercialize this environmentally sound source of energy/power system, development of suitable CO-tolerant catalyst is needed. In this work, we have synthesized several novel electrocatalysts (Pt/C, Pt/Ru/C Pt/Mo/C, Pt/Ir and Pt/Ru/Mo) for PEMFCs. These catalysts have been tested for CO tolerance in the H{sub 2}/air fuel cell. The concentration of CO in the H{sub 2} fuel varied from 10 ppm to 100 ppm. The performance of the electrodes was evaluated by determining the cell potential against current density. The effect of temperature, catalyst compositions, and electrode film preparation methods on the performance of PEM fuel cell has also been studied. It was found that at 70 C and 3.5 atm pressure at the cathode, Pt-alloy catalysts (10 wt % Pt/Ru/C, 20 wt % Pt/Mo/C) were more CO-tolerant than 20 wt % Pt catalyst alone. It was also observed that spraying method is better for the preparation of electrode film than the brushing technique. Some of these results are summarized in this report.

  19. A combined capillary cooling system for cooling fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Ana Paula; Pelizza, Pablo Rodrigo; Galante, Renan Manozzo; Bazzo, Edson [Universidade Federal de Santa Catarina (LabCET/UFSC), Florianopolis, SC (Brazil). Dept. de Engenharia Mecanica. Lab. de Combustao e Engenharia de Sistemas Termicos], Emails: ana@labcet.ufsc.br, pablo@labcet.ufsc.br, renan@labcet.ufsc.br, ebazzo@emc.ufsc.br

    2010-07-01

    The operation temperature control has an important influence over the PEMFC (Proton Exchange Membrane Fuel Cell) performance. A two-phase heat transfer system is proposed as an alternative for cooling and thermal control of PEMFC. The proposed system consists of a CPL (Capillary Pumped Loop) connected to a set of constant conductance heat pipes. In this work ceramic wick and stainless mesh wicks have been used as capillary structure of the CPL and heat pipes, respectively. Acetone has been used as the working fluid for CPL and deionized water for the heat pipes. Experimental results of three 1/4 inch stainless steel outlet diameter heats pipes and one CPL have been carried out and presented in this paper. Further experiments are planned coupling the proposed cooling system to a module which simulates the fuel cell. (author)

  20. Reactivation System for Proton-Exchange Membrane Fuel-Cells

    Directory of Open Access Journals (Sweden)

    Roberto Giral

    2012-07-01

    Full Text Available In recent years, Proton-Exchange Membrane Fuel Cells (PEMFCs have been the focus of very intensive researches. Manufacturers of these alternative power sources propose a rejuvenation sequence after the FC has been operating at high power for a certain period of time. These rejuvenation methods could be not appropriate for the reactivation of the FC when it has been out of operation for a long period of time or after it has been repaired. Since the developed reactivation system monitors temperature, current, and the cell voltages of the stack, it could be also useful for the diagnostic and repairing processes. The limited number of published contributions suggests that systems developing reactivation techniques are an open research field. In this paper, an automated system for reactivating PEMFCs and results of experimental testing are presented.

  1. DESENVOLVIMENTO REGIONAL E URBANO: EFICIÊNCIA, SUSTENTABILIDADE E FINANCIAMENTO

    Directory of Open Access Journals (Sweden)

    João Serafim Tusi Da Silveira

    2014-01-01

    Full Text Available No financiamento de políticas de desenvolvimento regional no Brasil, o papel do Estado é imprescindível, ainda que tenha beneficiado elites locais e deixado regiões estagnadas. Esses efeitos podem ser atenuados com políticas em que os novos créditos dependam dos objetivos a serem alcançados. Neste artigo, a investigação desta premissa fundamenta-se na dinâmica do desenvolvimento socioeconômico sustentável de Celso Furtado. Para sua verificação, estimou-se um modelo de fronteira estocástica de eficiência técnica do desenvolvimento regional e urbano dos municípios catarinenses e suas 30 Secretarias de Desenvolvimento Regional. Os resultados obtidos não são conclusivos, mas deveras intrigantes. Verificou-se, por exemplo, que 12 regionais responderam por cerca de 80% do montante financiado, do qual, aproximadamente, 67% foram para 6 secretarias, cujos municípios estão entre os mais desenvolvidos e melhor posicionados no ranking dos fatores de sustentabilidade, embora um bom número deles não esteja incluído entre os mais eficientes.

  2. Platinum redispersion on metal oxides in low temperature fuel cells

    DEFF Research Database (Denmark)

    Tripkovic, Vladimir; Cerri, Isotta; Nagami, Tetsuo

    2013-01-01

    We have analyzed the aptitude of several metal oxide supports (TiO2, SnO2, NbO2, ZrO2, SiO2, Ta2O5 and Nb2O5) to redisperse platinum under electrochemical conditions pertinent to the Proton Exchange Membrane Fuel Cell (PEMFC) cathode. The redispersion on oxide supports in air has been studied in ...

  3. High Temperature PEM Fuel Cell Stacks with Advent TPS Meas

    Directory of Open Access Journals (Sweden)

    Neophytides Stylianos

    2017-01-01

    Full Text Available High power/high energy applications are expected to greatly benefit from high temperature Polymer Electrolyte Membrane Fuel Cells (PEMFCs. In this work, a combinatorial approach is presented, in which separately developed and evaluated MEAs, design and engineering are employed to result in reliable and effective stacks operating above 180°C and having the characteristics well matched to applications including auxiliary power, micro combined heat and power, and telecommunication satellites.

  4. Parametric Sensitivity Tests- European PEM Fuel Cell Stack Test Procedures

    DEFF Research Database (Denmark)

    Araya, Samuel Simon; Andreasen, Søren Juhl; Kær, Søren Knudsen

    2014-01-01

    performed based on test procedures proposed by a European project, Stack-Test. The sensitivity of a Nafion-based low temperature PEMFC stack’s performance to parametric changes was the main objective of the tests. Four crucial parameters for fuel cell operation were chosen; relative humidity, temperature......, pressure, and stoichiometry at varying current density. Furthermore, procedures for polarization curve recording were also tested both in ascending and descending current directions....

  5. From A Fundamental Study on Hydrogen Bond Network and Chain Mobility in Benzimidazole Model Compounds to Various Designs and Development of Benzimidazole-based Anhydrous Membranes for Proton Exchange Membrane Fuel Cell

    Directory of Open Access Journals (Sweden)

    Suwabun Chirachanchai

    2011-12-01

    Full Text Available A series of N-containing heterocycles i.e., imidazole and benzimidazole are systematically designed to study how proton transfer in anhydrous system is related to hydrogen bond network and molecular mobility. The work extends to polymers containing heterocycles to clarify the proton conductivity in proton exchange membrane fuel cell (PEMFC.

  6. Récupération du platine contenu dans les piles à combustible basse température par voie hydrométallurgique Platinum Recovery from used PEMFC by hydrometallurgy

    Directory of Open Access Journals (Sweden)

    Vincent Denis

    2013-11-01

    Full Text Available La récupération du platine contenu dans la couche catalytique des piles à combustible est nécessaire pour viabiliser cette technologie vers le secteur industriel. Dans cette étude la voie purement hydrométallurgique a été privilégiée au procédé de récupération pyrométallurgique, évitant la destruction des autres constituants de la pile (membrane, … et limitant la formation de gaz toxique. Le procédé mise en œuvre est constitué d'une étape de lixiviation à partir d'un mélange HCl/HNO3, suivie par la précipitation d'un sel de platine (NH42PtCl6 pouvant soit servir à la synthèse d'un nouveau catalyseur soit à l'obtention de platine métallique. Sur l'ensemble de la chaîne un rendement de récupération de plus de 80 % a pu être obtenu mettant en avant le potentiel de cette stratégie. The recovery of platinum in the catalyst layers of PEMFCs (proton exchange membrane fuel cells is required to allow a transfer in industry. In this study, hydrometallurgical route was preferred to pyrometallurgical process, reducing both the destruction of the other components of the cell (membrane, … and the formation of hazardous gas. In this work, the process includes a leaching step from a diluted aqua regia solution, followed by a precipitation step of platinum under the (NH42PtCl6 form. This salt can be used either for the synthesis of a new catalyst or to obtain a metallic platinum. Considering these steps the recovery efficiency has been found to be over 80 %, which bring out the potential of this strategy.

  7. Nano/micro-patterning the membrane-electrocatalyst layer for fuel cell applications

    Science.gov (United States)

    Omosebi, Ayokunle O.

    Polymer electrolyte membrane fuel cells (PEMFCs) are high energy density electrochemical devices capable of directly converting stored chemical potential into electricity. Their many attributes, including low emissions, quiet operation, scalability, modularity and efficiency make them attractive alternatives to conventional portable and stationary power sources. The emergence of the PEMFC as a dominant technology for electrical power generation is however currently limited by performance losses and the cost of the membrane electrode assembly (MEA). The basic architecture of the MEA, which has remained largely unchanged for over four decades, consists of ink-based platinum supported on carbon catalyst layers dispersed on either side of a Nafion membrane. In order to generate power from the electrochemical reaction, protons, electrons, and oxidant must be available at the catalyst layer-Nafion ionomer interface. As such, to improve performance, the availability of this interface should be maximized without increasing the transport resistance for reactants accessing the reaction plane. To achieve this objective, the membrane-electrode interface could be restructured to possess a larger interfacial area by creating nano/microfeatures on the Nafion membrane. This work introduces electron beam lithography coupled with dry etching and sputtering strategies for creating membrane-electrode structures with over-potential suppression characteristics in PEMFCs. Electron beam lithography provides the ability to fabricate nano/microfeatures in an electron beam sensitive material, while pattern transfer and aspect-ratio control is achieved with dry etching. Conventional and ultra-thin catalyst layers were fabricated by spraying and sputter deposition, and methanol and hydrogen were tested as fuels. Experiments involving the patterned MEA elucidate improved properties that lead to PEMFC performance enhancement. The ability to directly pattern a Nafion membrane

  8. Effect of nitrogen crossover on purging strategy in PEM fuel cell systems

    DEFF Research Database (Denmark)

    Rabbani, Raja Abid; Rokni, Masoud

    2013-01-01

    A comprehensive study on nitrogen crossover in polymer electrolyte membrane fuel cell (PEMFC) system with anode recirculation is conducted and associated purging strategies are discussed. Such systems when employed in automobiles are subjected to continuous changes in load and external operating ...... levels from rising when compared to a fixed purge interval strategy. This model can be used as a base for control and development of anode purge strategies for automotive fuel cell systems....

  9. Local impact of humidification on degradation in polymer electrolyte fuel cells

    Science.gov (United States)

    Sanchez, Daniel G.; Ruiu, Tiziana; Biswas, Indro; Schulze, Mathias; Helmly, Stefan; Friedrich, K. Andreas

    2017-06-01

    The water level in a polymer electrolyte membrane fuel cell (PEMFC) affects the durability as is seen from the degradation processes during operation a PEMFC with fully- and nonhumidified gas streams as analyzed using an in-situ segmented cell for local current density measurements during a 300 h test operating under constant conditions and using ex situ SEM/EDX and XPS post-test analysis of specific regions. The impact of the RH on spatial distribution of the degradation process results from different water distribution giving different chemical environments. Under nonhumidified gas streams, the cathode inlet region exhibits increased degradation, whereas with fully humidified gases the bottom of the cell had the higher performance losses. The degradation and the degree of reversibility produced by Pt dissolution, PTFE defluorination, and contaminants such as silicon (Si) and nickel (Ni) were locally evaluated.

  10. Studies on PEM Fuel Cell Noble Metal Catalyst Dissolution

    DEFF Research Database (Denmark)

    Ma, Shuang; Skou, Eivind Morten

    Incredibly vast advance has been achieved in fuel cell technology regarding to catalyst efficiency, improvement of electrolyte conductivity and optimization of cell system. With breathtakingly accelerating progress, Proton Exchange Membrane Fuel Cells (PEMFC) is the most promising and most widely....... Membrane Electrode Assembly (MEA) is commonly considered as the heart of cell system [2]. Degradation of the noble metal catalysts in MEAs especially Three-Phase-Boundary (TPB) is a key factor directly influencing fuel cell durability. In this work, electrochemical degradation of Pt and Pt/Ru alloy were...

  11. High power fuel cell simulator based on artificial neural network

    Energy Technology Data Exchange (ETDEWEB)

    Chavez-Ramirez, Abraham U.; Munoz-Guerrero, Roberto [Departamento de Ingenieria Electrica, CINVESTAV-IPN. Av. Instituto Politecnico Nacional No. 2508, D.F. CP 07360 (Mexico); Duron-Torres, S.M. [Unidad Academica de Ciencias Quimicas, Universidad Autonoma de Zacatecas, Campus Siglo XXI, Edif. 6 (Mexico); Ferraro, M.; Brunaccini, G.; Sergi, F.; Antonucci, V. [CNR-ITAE, Via Salita S. Lucia sopra Contesse 5-98126 Messina (Italy); Arriaga, L.G. [Centro de Investigacion y Desarrollo Tecnologico en Electroquimica S.C., Parque Tecnologico Queretaro, Sanfandila, Pedro Escobedo, Queretaro (Mexico)

    2010-11-15

    Artificial Neural Network (ANN) has become a powerful modeling tool for predicting the performance of complex systems with no well-known variable relationships due to the inherent properties. A commercial Polymeric Electrolyte Membrane fuel cell (PEMFC) stack (5 kW) was modeled successfully using this tool, increasing the number of test into the 7 inputs - 2 outputs-dimensional spaces in the shortest time, acquiring only a small amount of experimental data. Some parameters could not be measured easily on the real system in experimental tests; however, by receiving the data from PEMFC, the ANN could be trained to learn the internal relationships that govern this system, and predict its behavior without any physical equations. Confident accuracy was achieved in this work making possible to import this tool to complex systems and applications. (author)

  12. Desenvolvimento moral e manifestações de polidez

    OpenAIRE

    Vebber, Fernanda Cañete

    2008-01-01

    Este texto propõe uma reflexão sobre a dimensão moral no âmbito educacional, buscando compreender uma possível relação entre desenvolvimento moral e manifestações de polidez. Diferentes perspectivas no campo da psicologia têm-se ocupado do estudo da moralidade, destacando-se a abordagem construtivista pelo viés de Jean Piaget e de sua obra O juízo moral na criança. Na relação entre desenvolvimento moral e manifestações de polidez, entende-se que há algo de moral na polidez, visto que ela trad...

  13. Desenvolvimento de uma ontologia sobre componentes de ontologias

    Directory of Open Access Journals (Sweden)

    Gisele Vasconcelos Dziekaniak

    Full Text Available Apresenta os principais passos no desenvolvimento da ontologia de domínio sobre Componentes de Ontologias. Demonstra como se chegou metodologicamente à ontologia, desenvolvida no Ontokem e exportada para o Protégé 3.3.1, onde foram desenvolvidas as inferências via Pellet 1.5.2 para fazê-la inferir sobre perguntas. As metodologias utilizadas foram Methontology, 101 e On-to-knowledge. Como resultado apresenta breve revisão de literatura sobre ontologias e um passo-a-passo do seu desenvolvimento para auxiliar quem deseja aventurar-se no caminho da construção de ontologias com o objetivo de classificação do conhecimento.

  14. R&D on an Ultra-Thin Composite Membrane for High-Temperature Operation in PEMFC. Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Yuh, C.-Y.

    2003-10-06

    FuelCell Energy developed a novel high-temperature proton exchange membrane for PEM fuel cells for building applications. The laboratory PEM fuel cell successfully operated at 100-400{supdegree}C and low relative humidity to improve CO tolerance, mitigate water and thermal management challenges, and reduce membrane cost. The developed high-temperature membrane has successfully completed 500h 120C endurance testing.

  15. TURISMO: FERRAMENTA DE DESENVOLVIMENTO DE REGIÕES

    Directory of Open Access Journals (Sweden)

    Michele Vasconcellos Chiattone

    2015-08-01

    Full Text Available Esse artigo tem como foco a Mesorregião Metade Sul do estado do Rio Grande do Sul com suas regiões e microrregiões, descrevendo as cidades que as compõe com alguns de seus dados demográficos, econômicos e culturais; a estrutura de serviços para o turismo, os atrativos turísticos; e algumas rotas turísticas. Também enfoca o desenvolvimento do turismo na Metade Sul com os benefícios econômicos da atividade, o turismo rural e o enoturismo. O objetivo do estudo é discutir a importância do turismo como ferramenta de desenvolvimento econômico e social da metade sul do Rio Grande do Sul do Brasil. O procedimento metodológico utilizado no estudo foi a pesquisa exploratória descritiva através de uma revisão bibliográfica em publicações físicas e digitais. O estado do Rio Grande do Sul encontra-se dividido em duas mesorregiões, Sul e Norte, sendo que há grande disparidade econômica e demografica entre elas. Nesse sentido, o turismo surge como alternativa visando minimizar essas desigualdades regionais, criando a união de municípios para promover o desenvolvimento regional dos territórios demarcados pelas rotas. Palavras-chave: Turismo. Metade Sul. Roteiro turístico. Desenvolvimento.

  16. Performance enhancement of polymer electrolyte membrane fuel cells by dual-layered membrane electrode assembly structures with carbon nanotubes.

    Science.gov (United States)

    Jung, Dong-Won; Kim, Jun-Ho; Kim, Se-Hoon; Kim, Jun-Bom; Oh, Eun-Suok

    2013-05-01

    The effect of dual-layered membrane electrode assemblies (d-MEAs) on the performance of a polymer electrolyte membrane fuel cell (PEMFC) was investigated using the following characterization techniques: single cell performance test, electrochemical impedance spectroscopy (EIS), and cyclic voltammetry (CV). It has been shown that the PEMFC with d-MEAs has better cell performance than that with typical mono-layered MEAs (m-MEAs). In particular, the d-MEA whose inner layer is composed of multi-walled carbon nanotubes (MWCNTs) showed the best fuel cell performance. This is due to the fact that the d-MEAs with MWCNTs have the highest electrochemical surface area and the lowest activation polarization, as observed from the CV and EIS test.

  17. Spectrophotometric Analysis of Phosphoric Acid Leakage in High-Temperature Phosphoric Acid-Doped Polybenzimidazole Membrane Fuel Cell Application

    Directory of Open Access Journals (Sweden)

    Seungyoon Han

    2016-01-01

    Full Text Available High-temperature proton exchange membrane fuel cells (HT-PEMFCs utilize a phosphoric acid- (PA- doped polybenzimidazole (PBI membrane as a polymer electrolyte. The PA concentration in the membrane can affect fuel cell performance, as a significant amount of PA can leak from the membrane electrode assembly (MEA by dissolution in discharged water, which is a byproduct of cell operation. Spectrophotometric analysis of PA leakage in PA-doped polybenzimidazole membrane fuel cells is described here. This spectrophotometric analysis is based on measurement of absorption of an ion pair formed by phosphomolybdic anions and the cationoid color reagent. Different color reagents were tested based on PA detection sensitivity, stability of the formed color, and accuracy with respect to the amount of PA measured. This method allows for nondestructive analysis and monitoring of PA leakage during HT-PEMFCs operation.

  18. Desenvolvimento humano: contribuições da psicologia moral

    Directory of Open Access Journals (Sweden)

    Yves de La Taille

    2007-03-01

    Full Text Available Procuramos avaliar as contribuições do conhecimento acumulado pela Psicologia Moral para a compreensão do desenvolvimento humano, para sustentar a tese segundo a qual a fonte energética do dever moral precisa ser procurada não só em sentimentos exclusivamente morais, mas também em sentimentos que desempenham um papel para o próprio desenvolvimento humano no seu conjunto. Três são os passos da análise deste artigo. Em primeiro lugar, verifi car se há possibilidade de articulação entre teorias psicológicas que enfatizam a dimensão afetiva da moralidade (Freud e Durkheim e outras que enfatizam a dimensão intelectual (Piaget e Kohlberg. Em segundo lugar, uma vez constatada a impossibilidade dessa articulação, sustentar que o sentimento de vergonha, presente na moralidade mas também em outras dimensões do desenvolvimento humano, é condição necessária ao sentimento de obrigatoriedade. Finalmente, analisar se tal sentimento é passível de ser evocado como fonte energética essencial nas abordagens que enfatizam a dimensão intelectual da moralidade.

  19. O desenvolvimento do talento em uma perspectiva feminina

    Directory of Open Access Journals (Sweden)

    Renata Muniz Prado

    Full Text Available Diversos estudos enfatizam as dificuldades enfrentadas pela mulher que se destaca pelo seu potencial superior, ressaltando a influência das forças sociais e culturais no desenvolvimento e na expressão dos seus talentos. Conciliar os múltiplos papéis desempenhados pela mulher constitui um dos principais fatores inibidores da promoção do talento feminino. Sendo assim, este ensaio busca contribuir para maior compreensão do desenvolvimento do talento em mulheres e, com base em recentes investigações, discutir os fatores que facilitam e dificultam uma performance feminina de destaque. As informações apresentadas neste trabalho poderão suscitar o desenvolvimento de outros estudos sobre o talento feminino e auxiliar a elaboração e a implementação de programas e serviços de atendimento a crianças e adolescentes talentosas bem como de políticas públicas dirigidas a mulheres que trabalham.

  20. Protonic conductors for proton exchange membrane fuel cells: An overview

    Directory of Open Access Journals (Sweden)

    Jurado Ramon Jose

    2002-01-01

    Full Text Available At present, Nation, which is a perfluorinated polymer, is one of the few materials that deliver the set of chemical and mechanical properties required to perform as a good electrolyte in proton exchange membrane fuel cells (PEMFCs. However, Nation presents some disadvantages, such as limiting the operational temperature of the fuel system (So°C, because of its inability to retain water at higher temperatures and also suffers chemical crossover. In addition to these restrictions, Nation membranes are very expensive. Reducing costs and using environmentally friendly materials are good reasons to make a research effort in this field in order to achieve similar or even better fuel-cell performances. Glass materials of the ternary system SiO2-ZrO2-P2O5, hybrid materials based on Nation, and nanopore ceramic membranes based on SiO2 TiO2, Al2O3, etc. are considered at present, as promising candidates to replace Nation as the electrolyte in PEMFCs. These types of materials are generally prepared by sol-gel processes in order to tailor their channel-porous structure and pore size. In this communication, the possible candidates in the near future as electrolytes (including other polymers different than Nation in PEMFCs are briefly reviewed. Their preparation methods, their electrical transport properties and conduction mechanisms are considered. The advantages and disadvantages of these materials with respect to Nation are also discussed.

  1. A method for the ad hoc and real-time determination of the water balance in a PEMFC

    DEFF Research Database (Denmark)

    Berning, Torsten

    2014-01-01

    A novel method for the ad hoc and real-time determination of the water balance in a proton exchange membrane fuel cell is presented. The method requires the anode side of the fuel cell to be operated in open-ended mode and to use dry, pure hydrogen as is typical for vehicular applications...

  2. Fuel cells flows study

    International Nuclear Information System (INIS)

    Riva, R.; Bador, B.; Marchand, M.; Lebaigue, O.

    1999-01-01

    Fuel cells are energy converters, which directly and continuously produce electricity from paired oxidation reduction-reactions: In most cases, the reactants are oxygen and hydrogen with water as residue. There are several types of fuel cells using various electrolytes and working at different temperatures. Proton Exchange Membrane Fuel Cells are, in particular, studied in the GESTEAU facility. PEMFC performance is chiefly limited by two thermal-hydraulic phenomena: the drying of membranes and the flooding of gas distributors. Up to now, work has been focused on water flooding of gas channels. This has showed the influence of flow type on the electrical behaviour of the cells and the results obtained have led to proposals for new duct geometries. (authors)

  3. A nova agenda para o desenvolvimento e a reforma do sistema de desenvolvimento das Nações Unidas

    OpenAIRE

    Rosado, Sofia Fragateiro de Campos

    2016-01-01

    Com a adoção da Agenda 2030 que definiu as metas de desenvolvimento para os próximos 15 anos, as Nações Unidas e os seus Estados-Membros consideraram que é necessário ajustar a forma como a ONU tem abordado as questões de desenvolvimento de forma a garantir que está "apta para o seu propósito”. No contexto do meu estágio na Missão Portuguesa na sede das Nações Unidas em Nova Iorque realizado entre Janeiro e Junho de 2016, este relatório analisa a evolução da agenda para o de...

  4. Do desenvolvimento à governabilidade: a trajetória do Banco Mundial nos países em desenvolvimento

    Directory of Open Access Journals (Sweden)

    Vanessa Lara Antonini

    2016-12-01

    Full Text Available Este artigo tem como objetivo evidenciar, por meio de um resgate histórico da política norte-americana e das ações do Banco Mundial para os países em desenvolvimento, quais os principais fatores que levaram esta instituição a abarcar em suas orientações e diretrizes o setor educacional.

  5. CERVEJA ARTESANAL E DESENVOLVIMENTO REGIONAL EM SANTA CATARINA (BRASIL

    Directory of Open Access Journals (Sweden)

    Valdinho Pellin

    2016-12-01

    Full Text Available Discussões relacionadas ao fortalecimento do desenvolvimento regional tem estimulado um debate em relação a contribuições que Indicações Geográficas (IGs podem oferecer ao desenvolvimento. IGs se constituem em elemento de identificação de produtos ou serviços com seus territórios e podem oferecer contribuições importantes para o desenvolvimento regional, agregando valor aos produtos, facilitando o acesso a novos mercados e valorizando tradições locais. Este artigo procura discutir a importância da cerveja artesanal no contexto do desenvolvimento regional em Santa Catarina. Para tanto explora como objetivos específicos: (i caracterizar as discussões que estão ocorrendo em torno do reconhecimento da IG para chope e cerveja artesanal na região de Blumenau (SC; (ii identificar contribuições e desafios para o Desenvolvimento Regional de um possível reconhecimento da IG; e (iii caracterizar limites e potencialidades sinalizados pela iniciativa em curso. Metodologicamente trata-se de pesquisa analítica e descritiva baseada em estudo de caso de natureza exploratória. Como instrumento de coleta de dados se realizou entrevistas semiestruturadas com gestores de micro cervejarias artesanais da região e atores públicos e privados envolvidos diretamente nas discussões. Além destas fontes primárias o estudo fundamentou-se em fontes consubstanciadas pelos documentos produzidos nas reuniões de trabalho realizadas até o presente. Os principais resultados de análise destacam que um possível reconhecimento da IG poderia contribuir para o fortalecimento do setor, aumentando a competitividade, além de fortalecer a atividade turística na região. Entretanto para isso, alguns conflitos, surgidos no âmbito das discussões, precisam ser assumidos, superados ou mitigados

  6. Nutrição e desenvolvimento Nutrition and development

    Directory of Open Access Journals (Sweden)

    Ilma K. G. de Arruda

    1994-09-01

    Full Text Available As discussões sobre desenvolvimento e nutrição freqüentemente se realizam sob um duplo enfoque: aqueles que consideram o estado nutricional como reflexo do desenvolvimento, e os que admitem que a nutrição influencia fortemente no nível e ritmo desse desenvolvimento. Os autores focalizam o tema visualizando a nutrição como um fator decisivo para um bom desenvolvimento social e econômico, particularizando o fato de que as intervenções nutricionais podem contribuir para melhorias significativas nos resultados escolares, na produtividade do trabalho e na resistência às infecções. Assim, os reflexos da desnutrição na economia seriam evidentes: quer pelas limitações na expectativa de renda, quer pelo aumento dos custos dos compromissos que a população assume para proteger-se, quer pelos avultados custos ocultos de origem social - absenteísmo, acidentes do trabalho e rotatividade de pessoal. Em face dos propósitos de modernização e competitividade da economia, é inquestionável a necessidade da nutrição figurar bem alto na lista de prioridades nacionais. Com isso, promover-se-ia o desenvolvimento dos recursos humanos e a preservação desse capital, que é o ideário de uma economia socialmente responsável.Discussions on development and nutrition frequently have a double focus: one that considers nutritional status as a reflection of development, and another that admits that nutrition strongly influences the level and rhythm of development. The authors view nutrition as a decisive factor for adequate social and economic development, specifying the fact that nutritional interventions might contribute to significant improvements in individual classroom performance, productivity at the workplace, and resistance to infections. The implications of malnutrition for the economy are thus evident: either by limitations in income expectations, increased costs deriving from burdens assumed by the population to protect themselves, or

  7. Transient computation fluid dynamics modeling of a single proton exchange membrane fuel cell with serpentine channel

    Science.gov (United States)

    Hu, Guilin; Fan, Jianren

    The proton exchange membrane fuel cell (PEMFC) has become a promising candidate for the power source of electrical vehicles because of its low pollution, low noise and especially fast startup and transient responses at low temperatures. A transient, three-dimensional, non-isothermal and single-phase mathematical model based on computation fluid dynamics has been developed to describe the transient process and the dynamic characteristics of a PEMFC with a serpentine fluid channel. The effects of water phase change and heat transfer, as well as electrochemical kinetics and multicomponent transport on the cell performance are taken into account simultaneously in this comprehensive model. The developed model was employed to simulate a single laboratory-scale PEMFC with an electrode area about 20 cm 2. The dynamic behavior of the characteristic parameters such as reactant concentration, pressure loss, temperature on the membrane surface of cathode side and current density during start-up process were computed and are discussed in detail. Furthermore, transient responses of the fuel cell characteristics during step changes and sinusoidal changes in the stoichiometric flow ratio of the cathode inlet stream, cathode inlet stream humidity and cell voltage are also studied and analyzed and interesting undershoot/overshoot behavior of some variables was found. It was also found that the startup and transient response time of a PEM fuel cell is of the order of a second, which is similar to the simulation results predicted by most models. The result is an important guide for the optimization of PEMFC designs and dynamic operation.

  8. Fuel Cells: A Real Option for Unmanned Aerial Vehicles Propulsion

    Science.gov (United States)

    2014-01-01

    The possibility of implementing fuel cell technology in Unmanned Aerial Vehicle (UAV) propulsion systems is considered. Potential advantages of the Proton Exchange Membrane or Polymer Electrolyte Membrane (PEMFC) and Direct Methanol Fuel Cells (DMFC), their fuels (hydrogen and methanol), and their storage systems are revised from technical and environmental standpoints. Some operating commercial applications are described. Main constraints for these kinds of fuel cells are analyzed in order to elucidate the viability of future developments. Since the low power density is the main problem of fuel cells, hybridization with electric batteries, necessary in most cases, is also explored. PMID:24600326

  9. Fuel cells: a real option for Unmanned Aerial Vehicles propulsion.

    Science.gov (United States)

    González-Espasandín, Óscar; Leo, Teresa J; Navarro-Arévalo, Emilio

    2014-01-01

    The possibility of implementing fuel cell technology in Unmanned Aerial Vehicle (UAV) propulsion systems is considered. Potential advantages of the Proton Exchange Membrane or Polymer Electrolyte Membrane (PEMFC) and Direct Methanol Fuel Cells (DMFC), their fuels (hydrogen and methanol), and their storage systems are revised from technical and environmental standpoints. Some operating commercial applications are described. Main constraints for these kinds of fuel cells are analyzed in order to elucidate the viability of future developments. Since the low power density is the main problem of fuel cells, hybridization with electric batteries, necessary in most cases, is also explored.

  10. Fuel Cells: A Real Option for Unmanned Aerial Vehicles Propulsion

    Directory of Open Access Journals (Sweden)

    Óscar González-Espasandín

    2014-01-01

    Full Text Available The possibility of implementing fuel cell technology in Unmanned Aerial Vehicle (UAV propulsion systems is considered. Potential advantages of the Proton Exchange Membrane or Polymer Electrolyte Membrane (PEMFC and Direct Methanol Fuel Cells (DMFC, their fuels (hydrogen and methanol, and their storage systems are revised from technical and environmental standpoints. Some operating commercial applications are described. Main constraints for these kinds of fuel cells are analyzed in order to elucidate the viability of future developments. Since the low power density is the main problem of fuel cells, hybridization with electric batteries, necessary in most cases, is also explored.

  11. Polymer and Composite Membranes for Proton-Conducting, High-Temperature Fuel Cells: A Critical Review.

    Science.gov (United States)

    Quartarone, Eliana; Angioni, Simone; Mustarelli, Piercarlo

    2017-06-22

    Polymer fuel cells operating above 100 °C (High Temperature Polymer Electrolyte Membrane Fuel Cells, HT-PEMFCs) have gained large interest for their application to automobiles. The HT-PEMFC devices are typically made of membranes with poly(benzimidazoles), although other polymers, such as sulphonated poly(ether ether ketones) and pyridine-based materials have been reported. In this critical review, we address the state-of-the-art of membrane fabrication and their properties. A large number of papers of uneven quality has appeared in the literature during the last few years, so this review is limited to works that are judged as significant. Emphasis is put on proton transport and the physico-chemical mechanisms of proton conductivity.

  12. A Central Composite Face-Centered Design for Parameters Estimation of PEM Fuel Cell Electrochemical Model

    Directory of Open Access Journals (Sweden)

    Khaled MAMMAR

    2013-11-01

    Full Text Available In this paper, a new approach based on Experimental of design methodology (DoE is used to estimate the optimal of unknown model parameters proton exchange membrane fuel cell (PEMFC. This proposed approach combines the central composite face-centered (CCF and numerical PEMFC electrochemical. Simulation results obtained using electrochemical model help to predict the cell voltage in terms of inlet partial pressures of hydrogen and oxygen, stack temperature, and operating current. The value of the previous model and (CCF design methodology is used for parametric analysis of electrochemical model. Thus it is possible to evaluate the relative importance of each parameter to the simulation accuracy. However this methodology is able to define the exact values of the parameters from the manufacture data. It was tested for the BCS 500-W stack PEM Generator, a stack rated at 500 W, manufactured by American Company BCS Technologies FC.

  13. Pt nanoparticle-reduced graphene oxide nanohybrid for proton exchange membrane fuel cells.

    Science.gov (United States)

    Park, Dae-Hwan; Jeon, Yukwon; Ok, Jinhee; Park, Jooil; Yoon, Seong-Ho; Choy, Jin-Ho; Shul, Yong-Gun

    2012-07-01

    A platinum nanoparticle-reduced graphene oxide (Pt-RGO) nanohybrid for proton exchange membrane fuel cell (PEMFC) application was successfully prepared. The Pt nanoparticles (Pt NPs) were deposited onto chemically converted graphene nanosheets via ethylene glycol (EG) reduction. According to the powder X-ray diffraction (XRD) pattern and transmission electron microscopy (TEM) analysis, the face-centered cubic Pt NPs (3-5 nm in diameter) were homogeneously dispersed on the RGO nanosheets. The electrochemically active surface area and PEMFC power density of the Pt-RGO nanohybrid were determined to be 33.26 m2/g and 480 mW/cm2 (maximum values), respectively, at 75 degrees C and at a relative humidity (RH) of 100% in a single-cell test experiment.

  14. An Equivalent Electrical Circuit Model of Proton Exchange Membrane Fuel Cells Based on Mathematical Modelling

    Directory of Open Access Journals (Sweden)

    Dinh An Nguyen

    2012-07-01

    Full Text Available Many of the Proton Exchange Membrane Fuel Cell (PEMFC models proposed in the literature consist of mathematical equations. However, they are not adequately practical for simulating power systems. The proposed model takes into account phenomena such as activation polarization, ohmic polarization, double layer capacitance and mass transport effects present in a PEM fuel cell. Using electrical analogies and a mathematical modeling of PEMFC, the circuit model is established. To evaluate the effectiveness of the circuit model, its static and dynamic performances under load step changes are simulated and compared to the numerical results obtained by solving the mathematical model. Finally, the applicability of our model is demonstrated by simulating a practical system.

  15. A Study of the Influence of Gas Channel Parameters on HT-PEM Fuel Cell Performance Using FEM Analysis

    Directory of Open Access Journals (Sweden)

    Ionescu Viorel

    2016-01-01

    Full Text Available Proton Exchange Membrane Fuel Cells (PEMFC are highly efficient power generators, achieving up to 50–60% conversion efficiency, even in sizes of a few kilowatts. Comsol Multiphysics, a commercial solver based on the Finite Element Method (FEM was used for developing a three dimensional model of a high temperature PEMFC that can deal with both anode and cathode flow field for examining the micro flow channel with electrochemical reaction. Cathode gas flow velocity influence on the cell performance was investigated at first. Polarization curves for three different channel widths (0.8, 1.6 and 2.4 mm and three different channel depths (1, 2 and 3 mm were computed at a cathode inlet flow velocity of 0.06 m/s. Oxygen molar concentration at cathode catalyst layer-GDL channel interface and local current density variation along the cell length were also studied for specific gas channel geometries.

  16. Current Density Distribution Mapping in PEM Fuel Cells as An Instrument for Operational Measurements

    Directory of Open Access Journals (Sweden)

    Martin Geske

    2010-04-01

    Full Text Available A newly developed measurement system for current density distribution mapping has enabled a new approach for operational measurements in proton exchange membrane fuel cells (PEMFC. Taking into account previously constructed measurement systems, a method based on a multi layer printed circuit board was chosen for the development of the new system. This type of system consists of a sensor, a special electronic device and the control and visualization PC. For the acquisition of the current density distribution values, a sensor device was designed and installed within a multilayer printed circuit board with integrated shunt resistors. Varying shunt values can be taken into consideration with a newly developed and evaluated calibration method. The sensor device was integrated in a PEM fuel cell stack to prove the functionality of the whole measurement system. A software application was implemented to visualize and save the measurement values. Its functionality was verified by operational measurements within a PEMFC system. Measurement accuracy and possible negative reactions of the sensor device during PEMFC operation are discussed in detail in this paper. The developed system enables operational measurements for different operating phases of PEM fuel cells. Additionally, this can be seen as a basis for new opportunities of optimization for fuel cell design and operation modes.

  17. Less sensitive electrocatalysts towards carbon monoxide for PEMFC fed by hydrogen produced from reforming gas; Recherche de catalyseurs peu sensibles a la presence de monoxyde de carbone pour piles a combustible PEMFC alimentees en gaz de reformage

    Energy Technology Data Exchange (ETDEWEB)

    Boucher, A.C.

    2002-11-15

    The aim of this work was to prepare bimetallic catalysts based on platinum to elaborate anodes for fuel cells fed by hydrogen produced from reforming gas and containing thus some ppm of carbon monoxide. In order to avoid platinum poisoning, another metal, such as tin, was added. This leads to a more tolerant material to CO. A Pt-Sn catalyst supported on Vulcan XC-72 carbon was prepared by a chemical route, using a platinum carbonyl complex. This material was characterized by physical and chemical methods which indicate that it is formed by nano-structured Pt{sub 3}Sn particles. These particles have a narrow size distribution with a mean diameter of approximately 2 nm. Its activity towards CO, particularly under fuel cell conditions, was compared with a similar commercial E-TEK catalyst. This study shows that the catalyst prepared from the carbonyl precursor is less sensitive to CO than the commercial one. (author)

  18. A polymer electrolyte fuel cell stack for stationary power generation from hydrogen fuel

    Energy Technology Data Exchange (ETDEWEB)

    Gottesfeld, S. [Los Alamos National Lab., NM (United States)

    1995-09-01

    The fuel cell is the most efficient device for the conversion of hydrogen fuel to electric power. As such, the fuel cell represents a key element in efforts to demonstrate and implement hydrogen fuel utilization for electric power generation. The low temperature, polymer electrolyte membrane fuel cell (PEMFC) has recently been identified as an attractive option for stationary power generation, based on the relatively simple and benign materials employed, the zero-emission character of the device, and the expected high power density, high reliability and low cost. However, a PEMFC stack fueled by hydrogen with the combined properties of low cost, high performance and high reliability has not yet been demonstrated. Demonstration of such a stack will remove a significant barrier to implementation of this advanced technology for electric power generation from hydrogen. Work done in the past at LANL on the development of components and materials, particularly on advanced membrane/electrode assemblies (MEAs), has contributed significantly to the capability to demonstrate in the foreseeable future a PEMFC stack with the combined characteristics described above. A joint effort between LANL and an industrial stack manufacturer will result in the demonstration of such a fuel cell stack for stationary power generation. The stack could operate on hydrogen fuel derived from either natural gas or from renewable sources. The technical plan includes collaboration with a stack manufacturer (CRADA). It stresses the special requirements from a PEMFC in stationary power generation, particularly maximization of the energy conversion efficiency, extension of useful life to the 10 hours time scale and tolerance to impurities from the reforming of natural gas.

  19. Corrosion-resistant, electrically-conductive plate for use in a fuel cell stack

    Science.gov (United States)

    Carter, J David [Bolingbrook, IL; Mawdsley, Jennifer R [Woodridge, IL; Niyogi, Suhas [Woodridge, IL; Wang, Xiaoping [Naperville, IL; Cruse, Terry [Lisle, IL; Santos, Lilia [Lombard, IL

    2010-04-20

    A corrosion resistant, electrically-conductive, durable plate at least partially coated with an anchor coating and a corrosion resistant coating. The corrosion resistant coating made of at least a polymer and a plurality of corrosion resistant particles each having a surface area between about 1-20 m.sup.2/g and a diameter less than about 10 microns. Preferably, the plate is used as a bipolar plate in a proton exchange membrane (PEMFC) fuel cell stack.

  20. An electro-kinetic study of oxygen reduction in polymer electrolyte fuel cells at intermediate temperatures

    OpenAIRE

    Gatto, I.; Stassi, A.; Passalacqua, E.; Arico, A. S.

    2013-01-01

    International audience; The oxygen reduction process in polymer electrolyte fuel cells (PEMFCs) was in-situ investigated at intermediate temperatures (80 e130 C) by using a carbon supported PtCo catalyst and Nafion membrane as electrolyte. To overcome the Nafion dehydration above 100 C, the experiments were carried out under pressurized conditions. Electro-kinetic parameters such as reaction order and activation energy were determined from the steady-state galvanostatic polarization curves ob...

  1. Parametric Sensitivity Tests—European Polymer Electrolyte Membrane Fuel Cell Stack Test Procedures

    DEFF Research Database (Denmark)

    Araya, Samuel Simon; Andreasen, Søren Juhl; Kær, Søren Knudsen

    2014-01-01

    performed based on test procedures proposed by a European project, Stack-Test. The sensitivity of a Nafion-based low temperature PEMFC stack’s performance to parametric changes was the main objective of the tests. Four crucial parameters for fuel cell operation were chosen; relative humidity, temperature......, pressure, and stoichiometry at varying current density. Furthermore, procedures for polarization curve recording were also tested both in ascending and descending current directions....

  2. Materials and characterization techniques for high-temperature polymer electrolyte membrane fuel cells.

    Science.gov (United States)

    Zeis, Roswitha

    2015-01-01

    The performance of high-temperature polymer electrolyte membrane fuel cells (HT-PEMFC) is critically dependent on the selection of materials and optimization of individual components. A conventional high-temperature membrane electrode assembly (HT-MEA) primarily consists of a polybenzimidazole (PBI)-type membrane containing phosphoric acid and two gas diffusion electrodes (GDE), the anode and the cathode, attached to the two surfaces of the membrane. This review article provides a survey on the materials implemented in state-of-the-art HT-MEAs. These materials must meet extremely demanding requirements because of the severe operating conditions of HT-PEMFCs. They need to be electrochemically and thermally stable in highly acidic environment. The polymer membranes should exhibit high proton conductivity in low-hydration and even anhydrous states. Of special concern for phosphoric-acid-doped PBI-type membranes is the acid loss and management during operation. The slow oxygen reduction reaction in HT-PEMFCs remains a challenge. Phosphoric acid tends to adsorb onto the surface of the platinum catalyst and therefore hampers the reaction kinetics. Additionally, the binder material plays a key role in regulating the hydrophobicity and hydrophilicity of the catalyst layer. Subsequently, the binder controls the electrode-membrane interface that establishes the triple phase boundary between proton conductive electrolyte, electron conductive catalyst, and reactant gases. Moreover, the elevated operating temperatures promote carbon corrosion and therefore degrade the integrity of the catalyst support. These are only some examples how materials properties affect the stability and performance of HT-PEMFCs. For this reason, materials characterization techniques for HT-PEMFCs, either in situ or ex situ, are highly beneficial. Significant progress has recently been made in this field, which enables us to gain a better understanding of underlying processes occurring during fuel cell

  3. Platinum redispersion on metal oxides in low temperature fuel cells.

    Science.gov (United States)

    Tripković, Vladimir; Cerri, Isotta; Nagami, Tetsuo; Bligaard, Thomas; Rossmeisl, Jan

    2013-03-07

    We have analyzed the aptitude of several metal oxide supports (TiO(2), SnO(2), NbO(2), ZrO(2), SiO(2), Ta(2)O(5) and Nb(2)O(5)) to redisperse platinum under electrochemical conditions pertinent to the Proton Exchange Membrane Fuel Cell (PEMFC) cathode. The redispersion on oxide supports in air has been studied in detail; however, due to different operating conditions it is not straightforward to link the chemical and the electrochemical environment. The largest differences reflect in (1) the oxidation state of the surface (the oxygen species coverage), (2) temperature and (3) the possibility of platinum dissolution at high potentials and the interference of redispersion with normal working potential of the PEMFC cathode. We have calculated the PtO(x) (x = 0, 1, 2) adsorption energies on different metal oxides' surface terminations as well as inside the metal oxides' bulk, and we have concluded that NbO(2) might be a good support for platinum redispersion at PEMFC cathodes.

  4. AS TECNOLOGIAS SOCIAIS COMO INSTRUMENTO PARA O DESENVOLVIMENTO NACIONAL

    Directory of Open Access Journals (Sweden)

    Aline Silva Seixas

    2015-12-01

    Full Text Available Este artigo objetiva construir o conceito de Tecnologias Sociais (TS com base em ideias já existentes na doutrina e na legislação, tendo em vista que ainda não existe um consenso por parte dos estudiosos do assunto sobre a concepção ideal acerca do tema. Além disso, pretende-se discutir a importância das TS para o Desenvolvimento social, ao passo em que por meio delas é possível progredir também no âmbito da inclusão social. Também é alvo do presente trabalho promover a regulamentação das TS e discutir a legislação vigente que trata destas, bem como os Projetos de Lei que tramitam no sentido de fornecer maior segurança jurídica para aqueles que se engajam no desenvolvimento das TS. Para tanto, utilizou-se da pesquisa bibliográfica, bem como da análise de artigos científicos, informações obtidas em sítios institucionais, estudo da legislação sobre o tema, além de impressões pessoais sobre a temática, frutos de discussões inovadoras diante de uma temática atual. Concluiu-se que as TS tem grande potencial para promover o Desenvolvimento nacional, de modo a contribuir para a inclusão social, para o fomento das pesquisas científicas e para a união da universidade com a sociedade. Ademais, constatou-se que o papel do Estado como fomentador de políticas públicas que envolvam as TS é fundamental, para que estas tenham sua eficácia colocada em prática.

  5. Desenvolvimento territorial rural no Brasil: limites e potencialidades dos CONSADs

    Directory of Open Access Journals (Sweden)

    Antonio César Ortega

    2007-06-01

    Full Text Available A motivação principal desse trabalho é avaliar a capacidade da abordagem territorial em contribuir com o enfrentamento da pobreza e das desigualdades sociais brasileiras, representando uma alternativa de geração de emprego e renda em territórios rurais deprimidos. Por meio dos Consórcios de Segurança Alimentar e Desenvolvimento Local (CONSADs analisa-se as potencialidades e as dificuldades que essa estratégia vem enfrentando para estabelecer a cooperação entre o poder público e a sociedade civil voltada para o fomento, o apoio logístico e a canalização de recursos para as iniciativas territoriais, projetos e ações estruturantes que visam a geração de emprego e renda, com a garantia de segurança alimentar e do desenvolvimento local.This paper aims at evaluating the capacity of the territorial approach to contribute to poverty issues and Brazilian social inequalities, representing an alternative of employment and income generation in depressed rural territories. Through Consórcios de Segurança Alimentar e Desenvolvimento Local-CONSADs (Food Safety Consortia and Local Development we analyzed the potentialities and difficulties the strategy is facing to establish the cooperation between public power and civil society regarding fomentation, logistic support and canalization of resources for territorial initiatives, projects and structuring actions that seek employment and income generation with food safety warranty and local development.

  6. Lazer como pratica educativa : as possibilidades para o desenvolvimento humano

    OpenAIRE

    Maira Ivone Lombardi

    2005-01-01

    Resumo: Os objetivos principais deste trabalho consistem em conhecer as inter-relações existentes entre lazer, educação, animação sociocultural e desenvolvimento humano integral e quais as possibilidades de se contribuir para a emancipação do indivíduo na sociedade, utilizando o lazer como prática educativa. Já os objetivos mais específicos são fundamentais à proposição de que o lazer como prática educativa, com base nos seis conteúdos culturais do lazer, pode contribuir para a formação de um...

  7. Perfil do desenvolvimento motor em escolares com excesso de peso

    Directory of Open Access Journals (Sweden)

    Mayara Moura Alves da Cruz

    2017-12-01

    Full Text Available Introdução: Diferenças relacionadas ao peso e as habilidades motoras em crianças em idade escolar ainda apresentam controversias. Objetivo: Analisar a relação entre desenvolvimento motor e nível de atividade física com o índice de massa corporal (IMC de escolares com excesso de peso. Métodos: Foram avaliados 85 escolares de ambos os sexos, de 6 a 10 anos, de Presidente Prudente, São Paulo, Brasil. Os instrumentos utilizados foram a classificação do IMC/idade, a Escala de Desenvolvimento Motor e o Questionário do Nível de Atividade Física Modificado e Adaptado. A amostra foi dividida em dois grupos: grupo com excesso de peso (GEP, com 50 escolares com diagnostico nutricional de sobrepeso e obesidade; e grupo com normopeso (GNP, com 35 escolares eutroficos. Para analise dos dados obtidos foram utilizados: Shapiro Wilk (normalidade, teste t de Student não pareado ou Mann Whitney (amostras independentes, teste de Spearman (correlação e teste do χ2 (proporção, com nível de significância p<0,05. Resultados: O GEP apresentou resultados inferiores significantes no desenvolvimento motor geral (91,32±10,68 versus 97,14±9,06; p=0,010, nas áreas de motricidade fina – QM1 (93,21±21,59 versus 103,1±13,12; p=0,0138 e motricidade global – QM2 (90,31±23,54 versus 112,6±16,07; p<0,0001. Observou-se correlação positiva significativa entre o nível de atividade física e o desenvolvimento motor no GEP, nas áreas de equilibrio – QM3 (0,35080; p=0,0125 e organização espacial – QM5 (0,41820; p=0,0025. Conclusão: O GEP, quando comparado com o GNP, demonstrou resultados inferiores no quociente motor geral (QMG, QM1 e QM2.

  8. Governança municipal do desenvolvimento local:

    OpenAIRE

    Jean Carlos Machado Alves; Gustavo Melo Silva

    2009-01-01

    O presente trabalho desenvolve um estudo teórico-empírico, que descreve e analisa as possibilidades de desenvolvimento local dos municípios de Resende Costa e Ritápolis. Esses municípios localizam-se no Campo das Vertentes, em Minas Gerais, e têm possibilidade de novos negócios na expansão do comércio artesanal local, vinculada ao incremento do turismo regional. No entanto, o sistema produtivo de Resende Costa pode levar à falta de sustentabilidade e o potencial de Ritápolis sinaliza uma nova...

  9. A agricultura familiar e o desenvolvimento no Brasil

    Directory of Open Access Journals (Sweden)

    Vilmar da Silva

    2013-07-01

    Full Text Available Este artigo tem como objetivo o de contribuir no debate sobre a agricultura familiar no país, apresentando um referencial de análise que permita entendê-la como uma tática de reprodução social e econômica das famílias rurais e sua contribuição para o desenvolvimento do país, a partir das múltiplas funções desenvolvidas pelos agricultores familiares e o trabalho desenvolvido por eles na agropecuária e nas regiões onde estão inseridos.

  10. A autoscopia e o desenvolvimento da autonomia docente

    OpenAIRE

    Carvalho, Diego Fogaça; Passos, Marinez Meneghello

    2014-01-01

    Neste artigo trazemos resultados sobre o uso de autoscopias no processo formativo de acadêmicos da licenciatura em matemática. As autoscopias são procedimentos de coleta de informações que visam à gravação da ação do sujeito e, na continuidade, coloca-o como avaliador de seu próprio desempenho. Em função da proposta investigativa desenvolvida e das análises realizadas, compreendemos que a autoscopia pode ser caracterizada como uma oportunidade de desenvolvimento da autonomia docente, levando ...

  11. Investigation of electrolyte leaching in the performance degradation of phosphoric acid-doped polybenzimidazole membrane-based high temperature fuel cells

    Science.gov (United States)

    Jeong, Yeon Hun; Oh, Kyeongmin; Ahn, Sungha; Kim, Na Young; Byeon, Ayeong; Park, Hee-Young; Lee, So Young; Park, Hyun S.; Yoo, Sung Jong; Jang, Jong Hyun; Kim, Hyoung-Juhn; Ju, Hyunchul; Kim, Jin Young

    2017-09-01

    Precise monitoring of electrolyte leaching in high-temperature polymer electrolyte membrane fuel cell (HT-PEMFC) devices during lifetime tests is helpful in making a diagnosis of their quality changes and analyzing their electrochemical performance degradation. Here, we investigate electrolyte leaching in the performance degradation of phosphoric acid (PA)-doped polybenzimidazole (PBI) membrane-based HT-PEMFCs. We first perform quantitative analyses to measure PA leakage during cell operation by spectrophotometric means, and a higher PA leakage rate is detected when the current density is elevated in the cell. Second, long-term degradation tests under various current densities of the cells and electrochemical impedance spectroscopy (EIS) analysis are performed to examine the influence of PA loss on the membrane and electrodes during cell performance degradation. The combined results indicate that PA leakage affect cell performance durability, mostly due to an increase in charge transfer resistance and a decrease in the electrochemical surface area (ECSA) of the electrodes. Additionally, a three-dimensional (3-D) HT-PEMFC model is applied to a real-scale experimental cell, and is successfully validated against the polarization curves measured during various long-term experiments. The simulation results highlight that the PA loss from the cathode catalyst layer (CL) is a significant contributor to overall performance degradation.

  12. Cross-linked poly (vinyl alcohol)/sulfosuccinic acid polymer as an electrolyte/electrode material for H2-O2 proton exchange membrane fuel cells

    Science.gov (United States)

    Ebenezer, D.; Deshpande, Abhijit P.; Haridoss, Prathap

    2016-02-01

    Proton exchange membrane fuel cell (PEMFC) performance with a cross-linked poly (vinyl alcohol)/sulfosuccinic acid (PVA/SSA) polymer is compared with Nafion® N-115 polymer. In this study, PVA/SSA (≈5 wt. % SSA) polymer membranes are synthesized by a solution casting technique. These cross-linked PVA/SSA polymers and Nafion are used as electrolytes and ionomers in catalyst layers, to fabricate different membrane electrode assemblies (MEAs) for PEMFCs. Properties of each MEA are evaluated using scanning electron microscopy, contact angle measurements, impedance spectroscopy and hydrogen pumping technique. I-V characteristics of each cell are evaluated in a H2-O2 fuel cell testing fixture under different operating conditions. PVA/SSA ionomer causes only an additional ≈4% loss in the anode performance compared to Nafion ionomer. The maximum power density obtained from PVA/SSA based cells range from 99 to 117.4 mW cm-2 with current density range of 247 to 293.4 mA cm-2. Ionic conductivity of PVA/SSA based cells is more sensitive to state of hydration of MEA, while maximum power density obtained is less sensitive to state of hydration of MEA. Maximum power density of cross-linked PVA/SSA membrane based cell is about 35% that of Nafion® N-115 based cell. From these results, cross-linked PVA/SSA polymer is identified as potential candidate for PEMFCs.

  13. Identification of critical parameters for PEMFC stack performance characterization and control strategies for reliable and comparable stack benchmarking

    DEFF Research Database (Denmark)

    Mitzel, Jens; Gülzow, Erich; Kabza, Alexander

    2016-01-01

    This paper is focused on the identification of critical parameters and on the development of reliable methodologies to achieve comparable benchmark results. Possibilities for control sensor positioning and for parameter variation in sensitivity tests are discussed and recommended options for the ......This paper is focused on the identification of critical parameters and on the development of reliable methodologies to achieve comparable benchmark results. Possibilities for control sensor positioning and for parameter variation in sensitivity tests are discussed and recommended options...... in an average cell voltage deviation of 21 mV. Test parameters simulating different stack applications are summarized. The stack demonstrated comparable average cell voltage of 0.63 V for stationary and portable conditions. For automotive conditions, the voltage increased to 0.69 V, mainly caused by higher...

  14. Application of the nanocomposite membrane as electrolyte of proton exchange membrane fuel cell

    International Nuclear Information System (INIS)

    Mahreni

    2010-01-01

    Hydrogen fuel cells proton exchange membrane fuel cell (PEMFC) is currently still in development and commercialization. Several barriers to the commercialization of these Nafion membrane as electrolyte is its very sensitive to humidity fluctuation. Nafion must be modified by making a composite Nafion-SiO 2 -HPA to increase electrolyte resistance against humidity fluctuations during the cell used. Research carried out by mixing Nafion solution with Tetra Ethoxy Ortho Silicate (TEOS) and conductive materials is phosphotungstic acid (PWA) by varying the ratio of Nafion, TEOS and PWA. The membrane is produced by heating a mixture of Nafion, TEOS and PWA by varying the evaporation temperature, time and annealing temperature to obtain the transparent membrane. The resulting membrane was analyzed its physical, chemical and electrochemical properties by applying the membrane as electrolyte of PEMFC at various humidity and temperature of operation. The results showed that at low temperatures (30-90 °C) and high humidity at 100 % RH, pure Nafion membrane is better than composite membrane (Nafion-SiO 2 -PWA), but at low humidity condition composite membrane is better than the pure Nafion membrane. It can be concluded that the composite membranes of (Nafion-SiO 2 -PWA) can be used as electrolyte of PEMFC operated at low humidity (40 % RH) and temperature between (30-90 °C). (author)

  15. Paradox phenomena of proton exchange membrane fuel cells operating under dead-end anode mode

    Science.gov (United States)

    Jiang, Dong; Zeng, Rong; Wang, Shumao; Jiang, Lijun; Varcoe, John R.

    2014-11-01

    By using two spatially separated reference electrodes in a single cell proton-exchange membrane fuel cell (PEMFC), the individual potentials of the anode and cathode are recorded under realistic operating conditions. The PEMFC is operated under dead-end anode (DEA) mode, without any humidification, to mitigate water accumulation at the anode. Although N2 crossover from cathode to anode may play an important role in PEMFCs operating under DEA mode, our results unexpectedly show that the over-potentials of both the anode and cathode concomitantly increased or decreased at the same time. The increases of over-potentials correlate to the increase of the high frequency resistance of the cell (Rhf) imply that the water content in the membrane electrode assemblies is critical. However, the subsequent H2 depletion tests suggest that water may accumulate at the interface between the surface of the catalyst and the ultrathin perfluorosulfonic acid (PFSA) ionomer film and this contradicts the above (the increase in Rhf implies the drying out of the MEAs). This study highlights the need for further research into understanding the water transport properties of the ultrathin PFSA ionomer film (<60 nm): it is clear that these exhibit completely different properties to that of bulk proton-exchange membranes (PEM).

  16. Proton Exchange Membrane Fuel Cell Reversal: A Review

    Directory of Open Access Journals (Sweden)

    Congwei Qin

    2016-12-01

    Full Text Available The H2/air-fed proton exchange membrane fuel cell (PEMFC has two major problems: cost and durability, which obstruct its pathway to commercialization. Cell reversal, which would create irreversible damage to the fuel cell and shorten its lifespan, is caused by reactant starvation, load change, low catalyst performance, and so on. This paper will summarize the causes, consequences, and mitigation strategies of cell reversal of PEMFC in detail. A description of potential change in the anode and cathode and the differences between local starvation and overall starvation are reviewed, which gives a framework for comprehending the origins of cell reversal. According to the root factor of cell starvation, i.e., fuel cells do not satisfy the requirements of electrons and protons of normal anode and cathode chemical reactions, we will introduce specific methods to mitigate or prevent fuel cell damage caused by cell reversal in the view of system management strategies and component material modifications. Based on a comprehensive understanding of cell reversal, it is beneficial to operate a fuel cell stack and extend its lifetime.

  17. DOE Award No. DE-FC36-03GO13108 NOVEL NON-PRECIOUS METAL CATALYSTS FOR PEMFC: CATALYST SELECTION THROUGH MOLECULAR MODELING AND DURABILITY STUDIES Final Report (September 2003 – October 2008)

    Energy Technology Data Exchange (ETDEWEB)

    Branko N. Popov

    2009-02-20

    The objective of this project is to develop novel non-precious metal electrocatalysts for oxygen reduction reaction (ORR), and demonstrate the potential of the catalysts to perform at least as good as conventional Pt catalysts currently in use in polymer electrolyte membrane fuel cell (PEMFC) with a cost at least 50 % less than a target of 0.2 g (Pt loading)/peak kW and with durability > 2,000 h operation with less than 10 % power degradation. A novel nitrogen-modified carbon-based catalyst was obtained by modifying carbon black with nitrogen-containing organic precursor in the absence of transition metal precursor. The catalyst shows the onset potential of approximately 0.76 V (NHE) for ORR and the amount of H2O2 of approximately 3% at 0.5 V (NHE). Furthermore, a carbon composite catalyst was achieved through the high-temperature pyrolysis of the precursors of transition metal (Co and Fe) and nitrogen supported on the nitrogen-modified carbon-based catalyst, followed by chemical post-treatment. This catalyst showed an onset potential for ORR as high as 0.87 V (NHE), and generated less than 1 % of H2O2. The PEM fuel cell exhibited a current density of 2.3 A cm-2 at 0.2 V for a catalyst loading of 6.0 mg cm-2. No significant performance degradation was observed for 480 h continuous operation. The characterization studies indicated that the metal-nitrogen chelate complexes decompose at the temperatures above 800 oC. During the pyrolysis, the transition metals facilitate the incorporation of pyridinic and graphitic nitrogen groups into the carbon matrix, and the carbon surface modified with nitrogen is active for ORR. In order to elucidate the role of transition metal precursor played in the formation of active sites in the non-precious metal catalysts, a novel ruthenium-based chelate (RuNx) catalyst was synthesized by using RuCl3 and propylene diammine as the Ru and N precursors, respectively, followed by high-temperature pyrolysis. This catalyst exhibited comparable

  18. DOE Award No. DE-FC36-03GO13108 NOVEL NON-PRECIOUS METAL CATALYSTS FOR PEMFC: CATALYST SELECTION THROUGH MOLECULAR MODELING AND DURABILITY STUDIES Final Report (September 2003 – October 2008)

    Energy Technology Data Exchange (ETDEWEB)

    Branko N. Popov

    2009-03-03

    The objective of this project is to develop novel non-precious metal electrocatalysts for oxygen reduction reaction (ORR), and demonstrate the potential of the catalysts to perform at least as good as conventional Pt catalysts currently in use in polymer electrolyte membrane fuel cell (PEMFC) with a cost at least 50 % less than a target of 0.2 g (Pt loading)/peak kW and with durability > 2,000 h operation with less than 10 % power degradation. A novel nitrogen-modified carbon-based catalyst was obtained by modifying carbon black with nitrogen-containing organic precursor in the absence of transition metal precursor. The catalyst shows the onset potential of approximately 0.76 V (NHE) for ORR and the amount of H2O2 of approximately 3% at 0.5 V (NHE). Furthermore, a carbon composite catalyst was achieved through the high-temperature pyrolysis of the precursors of transition metal (Co and Fe) and nitrogen supported on the nitrogen-modified carbon-based catalyst, followed by chemical post-treatment. This catalyst showed an onset potential for ORR as high as 0.87 V (NHE), and generated less than 1 % of H2O2. The PEM fuel cell exhibited a current density of 2.3 A cm-2 at 0.2 V for a catalyst loading of 6.0 mg cm-2. No significant performance degradation was observed for 480 h continuous operation. The characterization studies indicated that the metal-nitrogen chelate complexes decompose at the temperatures above 800 oC. During the pyrolysis, the transition metals facilitate the incorporation of pyridinic and graphitic nitrogen groups into the carbon matrix, and the carbon surface modified with nitrogen is active for ORR. In order to elucidate the role of transition metal precursor played in the formation of active sites in the non-precious metal catalysts, a novel ruthenium-based chelate (RuNx) catalyst was synthesized by using RuCl3 and propylene diammine as the Ru and N precursors, respectively, followed by high-temperature pyrolysis. This catalyst exhibited comparable

  19. A Review of Water Management in Polymer Electrolyte Membrane Fuel Cells

    Directory of Open Access Journals (Sweden)

    Zidong Wei

    2009-11-01

    Full Text Available At present, despite the great advances in polymer electrolyte membrane fuel cell (PEMFC technology over the past two decades through intensive research and development activities, their large-scale commercialization is still hampered by their higher materials cost and lower reliability and durability. In this review, water management is given special consideration. Water management is of vital importance to achieve maximum performance and durability from PEMFCs. On the one hand, to maintain good proton conductivity, the relative humidity of inlet gases is typically held at a large value to ensure that the membrane remains fully hydrated. On the other hand, the pores of the catalyst layer (CL and the gas diffusion layer (GDL are frequently flooded by excessive liquid water, resulting in a higher mass transport resistance. Thus, a subtle equilibrium has to be maintained between membrane drying and liquid water flooding to prevent fuel cell degradation and guarantee a high performance level, which is the essential problem of water management. This paper presents a comprehensive review of the state-of-the-art studies of water management, including the experimental methods and modeling and simulation for the characterization of water management and the water management strategies. As one important aspect of water management, water flooding has been extensively studied during the last two decades. Herein, the causes, detection, effects on cell performance and mitigation strategies of water flooding are overviewed in detail. In the end of the paper the emphasis is given to: (i the delicate equilibrium of membrane drying vs. water flooding in water management; (ii determining which phenomenon is principally responsible for the deterioration of the PEMFC performance, the flooding of the porous electrode or the gas channels in the bipolar plate, and (iii what measures should be taken to prevent water flooding from happening in PEMFCs.

  20. Desenvolvimento regional sob o enfoque pós-keynesiano

    Directory of Open Access Journals (Sweden)

    Júlia Elisabete Barden

    2007-01-01

    Full Text Available Este trabalho tem como objetivo fazer uma revisão bibliográfica acerca de estudosque analisam o desenvolvimento regional sob a perspectiva da teoria pós-keynesiana. Osresultados destes demonstram que o sistema financeiro, em especial os bancos,influenciam no grau de desenvolvimento das regiões, sobretudo, porque o comportamentodestes agentes segue um conceito importante utilizado pela teoria, a preferência pelaliquidez. Assim, a disponibilidade de crédito para investimento no sistema produtivosofrerá impactos importantes conforme a preferência pela liquidez dos bancos.Abstract This paper has as objective to bring a bibliographical review about the studies thatanalyze the regional development on the Post-Keynesian theory perspective. The resultsobtained show that the financial system especially the banks, however these agentsbehavior follow an important concept used by the theory, the preference to the liquidity.Yet, the credit responsibility for the investment in the productive system will sufferimportant impacts due to the preference for the liquidity from the banks.

  1. COPA DO MUNDO 2014: TURISMO, DESENVOLVIMENTO E SUSTENTABILIDADE NA CONTEMPORANEIDADE

    Directory of Open Access Journals (Sweden)

    Luciana Hoppe

    2015-08-01

    Full Text Available A atividade turística é um dos fenômenos mais significativos da contemporaneidade e cada vez mais tem se tornado objeto de pesquisas e estudos tanto no âmbito das ciências sociais aplicadas quanto das ciências humanas. Atenção essa que ganha vulto em função da complexa estrutura de serviços que envolve e, também, em razão do impacto que o turismo tem no cotidiano daquelas populações que habitam as cidades receptoras. Neste sentido, um dos modos pelos quais o turismo toma forma é aquele ligado aos eventos, em especial aos denominados megaeventos. Diante disso, este estudo busca refletir sobre a Copa do Mundo de 2014 realizada no Brasil no sentido de colaborar com a discussão acadêmica sobre megaeventos, seus impactos e desdobramentos no âmbito de uma perspectiva sinérgica entre desenvolvimento e sustentabilidade. Assim, defende-se no texto o argumento de que muitas são as formas como o turismo impacta na vida das pessoas e no interior das relações cotidianas daqueles que vivem nas cidades receptoras ganhando, assim, tangibilidade e concretude. Palavras-chave: Turismo. Desenvolvimento. Sustentabilidade. Megaevento. Copa do Mundo.

  2. Investimentos diretos estrangeiros e políticas de desenvolvimento

    Directory of Open Access Journals (Sweden)

    Antônio Corrêa de Lacerda

    2008-05-01

    Full Text Available O artigo discute alternativas para a inserção internacional da economia brasileira, especialmente no que se refere ao papel dos investimentos diretos estrangeiros, da geração de valor agregado local e do desempenho das exportações, a partir do cenário da globalização e suas transformações. Na primeira parte analisa-se a competitividade dos países em desenvolvimento e, na segunda parte, discutem-se estratégias de política econômica para uma inserção internacional mais ativa na economia brasileira. Palavras-chave: investimentos diretos estrangeiros; globalização; inserção externa; políticas de desenvolvimento. Abstract The article discusses alternatives for the international insertion of Brazilian economy especially considering the role of foreign direct investments, the creation of local aggregated value and the exportations performance from the scene of the globalization and its transformations. In the first part, the competitiveness of developing countries is analyzed and in the second part, strategies of economic policy for a more active international of Brazilian economy are discussed. Keywords: foreign direct investments, globalization, international insertion, development policies.

  3. PATRIMÔNIO CULTURAL ARQUEOLÓGICO: INSTRUMENTO DE DESENVOLVIMENTO TURÍSTICO

    OpenAIRE

    Rossano Bastos

    2012-01-01

    O presente trabalho trata das perspectivas de aproveitamento do Patrimônio Cultural Arqueológico como instrumento de desenvolvimento turístico.PALAVRAS-CHAVE: Arqueologia; Turismo;Desenvolvimento.ABSTRACT: This work considers some improvement perspectives ofthe archaeological cultural heritage as an instrument of tourism development.KEY-WORDS: Archaeology; Tourism; Development. 

  4. Desenvolvimento Policêntrico na Europa : Uma reflexao critica sobre um conceito de politicas normativas

    NARCIS (Netherlands)

    Meijers, E.J.

    Durante a última década, o desenvolvimento policêntrico tornou-se um conceito-chave no desenvolvimento territorial europeu. Em muitos aspectos, é um conceito difuso que significa diferentes coisas para diferentes pessoas em diferentes escalas espaciais. Neste artigo, analisamos as variadas

  5. Carbon-Nanotube-Supported Bio-Inspired Nickel Catalyst and Its Integration in Hybrid Hydrogen/Air Fuel Cells.

    Science.gov (United States)

    Gentil, Solène; Lalaoui, Noémie; Dutta, Arnab; Nedellec, Yannig; Cosnier, Serge; Shaw, Wendy J; Artero, Vincent; Le Goff, Alan

    2017-02-06

    A biomimetic nickel bis-diphosphine complex incorporating the amino acid arginine in the outer coordination sphere was immobilized on modified carbon nanotubes (CNTs) through electrostatic interactions. The functionalized redox nanomaterial exhibits reversible electrocatalytic activity for the H 2 /2 H + interconversion from pH 0 to 9, with catalytic preference for H 2 oxidation at all pH values. The high activity of the complex over a wide pH range allows us to integrate this bio-inspired nanomaterial either in an enzymatic fuel cell together with a multicopper oxidase at the cathode, or in a proton exchange membrane fuel cell (PEMFC) using Pt/C at the cathode. The Ni-based PEMFC reaches 14 mW cm -2 , only six-times-less as compared to full-Pt conventional PEMFC. The Pt-free enzyme-based fuel cell delivers ≈2 mW cm -2 , a new efficiency record for a hydrogen biofuel cell with base metal catalysts. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  6. Localised corrosion processes of austenitic stainless steel bipolar plates for polymer electrolyte membrane fuel cells

    Science.gov (United States)

    Mele, Claudio; Bozzini, Benedetto

    This research addresses the problem of localised corrosion of stainless steel PEMFC bipolar plates. The susceptibility to pitting and crevice corrosion of austenitic AISI 304 stainless steel has been investigated both by post-mortem microscopic analysis of the end-plates of a laboratory single-cell and by studies of electrochemically corroded stainless steels, in the presence of specially-designed crevice-formers simulating the operating conditions of a PEMFC. This work is based on optical and scanning-electron microscopies as well as potentiostatic and potentiodynamic measurements. The crevice-formers we considered were: Teflon, graphite and AISI 304. The samples, coupled to the crevice-formers have been tested in aqueous solutions containing Cl -, SO 4 2- and F -. From the E-log i plot, the values of corrosion, pitting, crevice and protection potential have been obtained and perfect and imperfect passivity conditions have been identified.

  7. Performance of plasma sputtered fuel cell electrodes with ultra-low Pt loadings

    Energy Technology Data Exchange (ETDEWEB)

    Cavarroc, M.; Ennadjaoui, A. [MID Dreux Innovation, CAdD, 4 Rue Albert Caquot-28500 Vernouillet (France); Mougenot, M.; Brault, P.; Escalier, R.; Tessier, Y. [Groupe de Recherches sur l' Energetique des Milieux Ionises, CNRS Universite d' Orleans, BP6744, 14 rue d' Issoudun, 45067 Orleans (France); Durand, J.; Roualdes, S. [Institut Europeen des Membranes, ENSCM, UM2, CNRS, Universite Montpellier 2, CC047, Place Eugene Bataillon, 34095 Montpellier cedex 5 (France); Sauvage, T. [Conditions Extremes et Materiaux, Haute Temperature et Irradiation, UPR3079 CNRS, Site Cyclotron, 3A rue de la Ferollerie, 45071 Orleans Cedex 2 (France); Coutanceau, C. [Laboratoire de Catalyse en Chimie Organique, UMR6503 Universite de Poitiers, CNRS, 86022, Poitiers (France)

    2009-04-15

    Ultra-low Pt content PEMFC electrodes have been manufactured using magnetron co-sputtering of carbon and platinum on a commercial E-Tek {sup registered} uncatalyzed gas diffusion layer in plasma fuel cell deposition devices. Pt loadings of 0.16 and 0.01 mg cm{sup -2} have been realized. The Pt catalyst is dispersed as small clusters with size less than 2 nm over a depth of 500 nm. PEMFC test with symmetric electrodes loaded with 10 {mu}g cm{sup -2} led to maximum reproducible power densities as high as 0.4 and 0.17 W cm{sup -2} with Nafion {sup registered} 212 and Nafion {sup registered} 115 membranes, respectively. (author)

  8. Carbon nanostructures as catalyst support for polymer electrolyte membrane fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Natarajan, S.K.; Hamelin, J. [Quebec Univ., Trois Rivieres, PQ (Canada). Inst. de recherche sur l' hydrogene

    2008-07-01

    This paper reported on a study that investigated potential alternatives to Vulcan XC-72 as a catalyst supports for polymer electrolyte membrane fuel cells (PEMFCs). These included carbon nanostructures (CNS) prepared by high energy ball milling of graphite and transition metal catalysts, followed by heat treatment. Among the key factors discussed were the graphitic content, high surface area, microporous structure, good electrical conductivity and the ability of the material to attach functional groups. Some graphic results supporting the usage of CNS as catalyst support for PEMFCs were presented. Upon chemical oxidation, surface functional groups such as carbonyl, carboxyl, and hydroxyl were populated on the surface of CNS. Nanosized platinum particles with particle size distribution between 3 nm and 5 nm were reduced on the functionalized sites of CNS in a colloidal medium. The paper also presented cyclic voltammograms, XPS, HRTEM and PSD results. 3 refs.

  9. Thematic outlook. Technical outlook for the fuel-cell research network (PACo). September 19, 2001 update, no. 1; Veille thematique. La veille technique pour le reseau PACo. Actualisation du 19 septembre 2001, no. 1

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2001-09-01

    This report brings together a compilation of abstracts of articles about some recent research works carried out in the domain of fuel cells, hydrogen production and hydrogen storage: dynamical behaviour of a PEM fuel cell for stationary applications; characterization of the Ballard's MK5-E PEMFC; modeling and analysis of a PEM system for transportation system applications; increase of the performances of a PEMFC by the optimization of the membrane and of the conditions of humidification; SOFC: exo-thermal reaction and heat source; average temperature SOFCs; performance and structure of a new CoO/Ni-based cathode for MCFC; choice of materials for fuel cell technology; recent trends of fuel cell-powered vehicles; hydrogen production in supercritical liquids for fuel cell use; on-board fuel conversion for fuel cells: comparison of the different fuels by numerical simulation; hydrogen production systems for fuel cells; reactor for the preferential catalytic oxidation of carbon monoxide (PROX) for PEMFC systems devoted to automotive vehicles; study of a gasoline reformer for fuel cell-powered vehicle applications; experimental research about hydrogen production from n-octane partial oxidation and vapo-reforming; simulation study of hydrogen storage in mono-sheet carbon nano-tubes; hydrogen adsorption in carbonized nano-structures; specific properties of the hydrogen engine; biomass power plants: a spectacular expansion in Germany. (J.S.)

  10. New Polymer Electrolyte Membranes Based on Acid Doped PBI For Fuel Cells Operating above 100°C

    DEFF Research Database (Denmark)

    Li, Qingfeng

    2003-01-01

    The technical achievement and challenges for the PEMFC technology based on perfluorosulfonic acid (PFSA) polymer membranes (e.g. Nafion®) are briefly discussed. The newest development for alternative polymer electrolytes for operation above 100°C. As one of the successful approaches to high opera...... operational temperatures, the development and evaluation of acid doped PBI membranes are reviewed, covering polymer synthesis, membrane casting, acid doping, physiochemical characterization and fuel cell tests....

  11. Fuel cell testing of Pt–Ru catalysts supported on differently prepared and pretreated carbon nanotubes

    International Nuclear Information System (INIS)

    Tokarz, Wojciech; Lota, Grzegorz; Frackowiak, Elzbieta; Czerwiński, Andrzej; Piela, Piotr

    2013-01-01

    Proton-exchange membrane fuel cell (PEMFC) testing of Pt–Ru catalysts supported on differently prepared multiwall carbon nanotube (MCNT) supports was performed to elucidate the influence of the different supports on the operating characteristics of the catalysts under real direct methanol fuel cell (DMFC) anode and H 2 -PEMFC anode conditions. The MCNTs were either thin, entangled or thick, disentangled. Pretreatment of the MCNTs was also done and it was either high-temperature KOH etching or annealing (graphitization). The performance of the catalysts was compared against the performance of a commercial Pt–Ru catalyst supported on a high-surface-area carbon black. Among the different MCNT supports, the graphitized, entangled support offered the best performance in all tests, which was equal to the performance of the commercial catalyst, despite the MCNT catalyst layer was ca. 2.2 times thicker than the carbon black catalyst layer. Even for an MCNT catalyst layer, which was almost 7 times thicker than the carbon black catalyst layer, the transport limitations were not prohibitive. This confirmed the expected potential of nanotube supports for providing superior reactant transport properties of the PEMFC catalyst layers

  12. O desenvolvimento corporal na educação infantil

    Directory of Open Access Journals (Sweden)

    Adriana Pacheco da Silva Santos

    2011-12-01

    Full Text Available Este artigo é resultado de um estudo realizado em uma creche pública pertencente à rede municipal de educação de Sinop - MT. Objetivamos compreender o movimento corporal das crianças como parte do desenvolvimento integral das crianças. E também entender como os profissionais trabalham a especificidade do corpo infantil, dos movimentos das crianças durante a rotina da instituição de uma turma de crianças de dois a três anos de idade. Optamos em focalizar a pesquisa na área da Educação Infantil por entender que as crianças desta faixa etária apresentam características importantes no desenvolvimento corporal, visto que muitas vezes na educação infantil o movimento é considerado como ‘indisciplina’, fazendo com que a criança, na maioria das vezes permanece quietas e sentadas em suas cadeiras. Diante de tal propósito, buscamos uma metodologia que nos possibilitasse apreender o movimento corporal da criança e encontramos na pesquisa qualitativa, através da ‘observação participante’, trilhas que nos conduziram à construção de conhecimentos. Como pesquisadora, permanecemos na instituição investigada por quase três meses, em horários intercalados, utilizando o caderno de campo, no qual registramos as observações realizadas, bem como as entrevistas com as professoras da referida turma. Os principais referenciais utilizados para o estudo foram: Vygotsky, Piaget, Vitor Fonseca e Henri Wallon. De acordo com o observado em campo e leituras teóricas, ressaltamos com este estudo a importância do movimento para as crianças e sua contribuição no desenvolvimento infantil pleno.Palavras-chave: educação; educação infantil; maternal II; movimento; sociointeracionismo.

  13. CARTOGRAFIAS DO PIAUÍ: RELACIONANDO INFRAESTRUTURA E DESENVOLVIMENTO SOCIAL

    Directory of Open Access Journals (Sweden)

    Paulo Antônio Barbosa Júnior

    2016-08-01

    Full Text Available Durante as décadas de 50 a 90, o Piauí foi o Estado mais pobre do Brasil. Recentemente, o Piauí tem apresentado acelerado crescimento econômico, devido em parte ao fortalecimento dos setores de comércio e construção, e a implantação da agricultura moderna na porção do Cerrado piauiense da região MAPITOBA. Apesar do recente incremento econômico, percebe-se que no Piauí, assim como em outros estados do Brasil, o desenvolvimento se dá de forma irregular com relação aos aspectos sociais e seus padrões de distribuição no território. Neste sentido, o presente trabalho busca mostrar que no Piauí a concentração de bens e pessoas está em parte condicionada a infraestrutura de transporte, com exceção da mesorregião Sudoeste Piauiense, onde o modelo de desenvolvimento adotado é essencialmente diferente do modelo das demais regiões. Desta forma, a baixa integração regional no Piauí tem contribuído para o surgimento de duas porções territoriais distintas e isoladas: uma ao norte, com características predominantemente urbanas e relativa concentração de bens e pessoas; e outra ao sul, onde se estabeleceu a última fronteira agrícola do país, com a implantação da agricultura moderna em áreas de vazios demográficos e baixos índices de desenvolvimento social. Assim, partindo-se da demanda por estudos que melhor descrevam as especificidades do território e que contribuam para a elaboração de políticas públicas adjetivadas ao local, o trabalho faz uso da Cartografia Temática e da Análise Espacial para descrever a situação atual do estado do Piauí com relação a Renda e Educação.

  14. Probing Formability Improvement of Ultra-thin Ferritic Stainless Steel Bipolar Plate of PEMFC in Non-conventional Forming Process

    Science.gov (United States)

    Bong, Hyuk Jong; Barlat, Frédéric; Lee, Myoung-Gyu

    2016-08-01

    Formability increase in non-conventional forming profiles programmed in the servo-press was investigated using finite element analysis. As an application, forming experiment on a 0.15-mm-thick ferritic stainless steel sheet for a bipolar plate, a primary component of a proton exchange membrane fuel cell, was conducted. Four different forming profiles were considered to investigate the effects of forming profiles on formability and shape accuracy. The four motions included conventional V motion, holding motion, W motion, and oscillating motion. Among the four motions, the holding motion, in which the slide was held for a certain period at the bottom dead point, led to the best formability. Finite element simulations were conducted to validate the experimental results and to probe the formability improvement in the non-conventional forming profiles. A creep model to address stress relaxation effect along with tool elastic recovery was implemented using a user-material subroutine, CREEP in ABAQUS finite element software. The stress relaxation and variable contact conditions during the holding and oscillating profiles were found to be the main mechanism of formability improvement.

  15. The Influence of Pt Atomic Ratio in the Activity PtNi/C Nanocatalysts for the PEMFC

    Directory of Open Access Journals (Sweden)

    Nenen Rusnaeni

    2011-08-01

    Full Text Available Pt-Ni/C alloy nanocatalysts synthesized by polyol method with different atomic ratio are investigated to enhance activity of the oxygen reduction reaction (ORR for fuel cell applications. Prepared catalysts are characterized by various techniques, such as X-ray diffraction (XRD, scanning electron microscopy (SEM-EDX, and cyclic voltammetry (CV. XRD analysis shows that all prepared catalysts with different atomic ratio exhibit face centered cubic and have smaller lattice parameters than pure Pt catalyst. The mean particle size of the catalysts are between 4.3 to 6.3 nm. Cyclic voltammograms with scan rate 5 mV s-1 at 25oC obtain range the electrochemical active surface (EAS between 40 to 164 cm2/mgPt, mass activity (MA and specific activity (SA of nanocatalysts PtNi/C in the potential range 900 mV versus RHE between 3.61 to 8.42 mA/mgPt, and 0.05 to 0.09.

  16. Thematic outlook: the technical survey for the fuel cell research network PACO. September 29, 2004 update no. 27; Veille thematique. La veille technique pour le reseau PACO. Actualisation du 29 septembre 2004, no. 27

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2004-07-01

    Summaries of several recent articles are gathered here. They deal with fuel cells, means of transport, hydrogen production and storage. Their different titles are given below: 1)the Germany countries agreement for fuel cells 2)electrochemical modelling of an IP-SOFC 3)design and performances of PEMFC tested with negative temperatures 4)carbon-air fuel cells without reforming process 5)exergy and economical analysis of a PAFC system of 200 kW 6)experience feedback on the use of a PAFC 7)experience feedback on the use of a PEMFC of 250 kW 8)hybrid fuel cell-powered vehicle: a possible solution of motorization 9)recent advancements in direct ethanol fuel cells: development of new platinum-tin electrocatalysts 10)review of components for SOFC anode 11)development of a fuel cell bicycle 12)steam reforming and water gas conversion by vapor permeation in a PCFC 13)modelling of an auto-thermal catalytic reformer for fuel cells applications 14)CO removal: system integrated to a preferential oxidation reactor for PEMFC vehicles 15)helio-hydraulic and helio-thermal hydrogen production 16)recent advances in the field of hydrogen storage in inorganic nano-structures containing metals 17)sequestration and storage of CO{sub 2}, the essential link for an hydrogen economy. The references of these articles are detailed. (O.M.)

  17. A Simulation Tool for Geometrical Analysis and Optimization of Fuel Cell Bipolar Plates: Development, Validation and Results

    Directory of Open Access Journals (Sweden)

    Javier Pino

    2009-07-01

    Full Text Available Bipolar plates (BPs are one of the most important components in Proton Exchange Membrane Fuel Cells (PEMFC due to the numerous functions they perform. The objective of the research work described in this paper was to develop a simplified and validated method based on Computational Fluid Dynamics (CFD, aimed at the analysis and study of the influence of geometrical parameters of BPs on the operation of a cell. A complete sensibility analysis of the influence of dimensions and shape of the BP can be obtained through a simplified CFD model without including the complexity of other components of the PEMFC. This model is compared with the PEM Fuel Cell Module of the FLUENT software, which includes the physical and chemical phenomena relevant in PEMFCs. Results with both models regarding the flow field inside the channels and local current densities are obtained and compared. The results show that it is possible to use the simple model as a standard tool for geometrical analysis of BPs, and results of a sensitivity analysis using the simplified model are presented and discussed.

  18. Mechanical Stability of H3PO4-Doped PBI/Hydrophilic-Pretreated PTFE Membranes for High Temperature PEMFCs

    International Nuclear Information System (INIS)

    Park, Jaehyung; Wang, Liang; Advani, Suresh G.; Prasad, Ajay K.

    2014-01-01

    Graphical abstract: - Highlights: • PBI/PTFE membrane was prepared by porous PTFE with hydrophilic surface pretreatment. • The durability of the prepared PBI/PTFE membrane was compared with pure PBI, PBI with untreated PTFE, and PBI-Nafion with untreated PTFE membranes. • Accelerated durability tests and SEM showed improved durability based the PBI/PTFE membrane with pretreated PTFE. - Abstract: A novel polybenzimidazole (PBI)/poly(tetrafluoroethylene) (PTFE) composite membrane doped with phosphoric acid was fabricated for high temperature operation in a polymer electrolyte membrane (PEM) fuel cell. A hydrophilic surface pretreatment was applied to the porous PTFE matrix film to improve its interfacial adhesion to the PBI polymer, thereby avoiding the introduction of Nafion ionomer which is traditionally used as a coupling agent. The pretreated PTFE film was embedded within the composite membrane during solution-casting using 5wt% PBI/DMAc solution. The mechanical stability and durability of three types of MEAs assembled with PBI only, PBI with pretreated PTFE, and PBI-Nafion with untreated PTFE membranes were evaluated under an accelerated degradation testing protocol employing extreme temperature cycling. Degradation was characterized by recording polarization curves, hydrogen crossover, and proton resistance. Cross-sections of the membranes were examined before and after thermal cycling by scanning electron microscope. Energy-dispersive X-ray spectroscopy verified that the PBI is dispersed homogeneously in the porous PTFE matrix. Results show that the PBI composite membrane with pretreated PTFE has a lower degradation rate than the Nafion/PBI membrane with untreated PTFE. Thus, the hydrophilic pretreatment employed here greatly improved the mechanical stability of the composite membrane, which resulted in improved durability under an extreme thermal cycling regime

  19. Desenvolvimento experimental de um motor stirling tipo gama.

    OpenAIRE

    Cruz, Vinicius Guimarães da

    2012-01-01

    O presente trabalho consiste no desenvolvimento experimental de um motor Stirling tipo gama. São apresentadas inicialmente as diferentes configurações deste tipo de motor (alfa, gama e beta), a definição do ciclo de Stirling e a modelagem matemática para cada configuração. Uma análise matemática é feita através da teoria de Schmidt, que é um método baseado na compressão e expansão isotérmica de um gás ideal, implementada em programa computacional permitindo determinar a dependência entre os p...

  20. Leptospirose animal: estudos para o desenvolvimento de vacinas recombinantes

    OpenAIRE

    Felix, Samuel Rodrigues

    2013-01-01

    A leptospirose é uma doença causada por espiroquetas do gênero Leptospira. É uma zoonose de ampla distribuição geográfica, sendo um problema de saúde pública e veterinária, principalmente em países subdesenvolvidos e em desenvolvimento de clima tropical e subtropical. Em medicina veterinária, a leptospirose é uma doença importante tanto para a clínica quanto para a produção, devido ao risco à saúde pública, perdas reprodutivas e óbitos. A vacinação animal é realizada como medida de prevenção ...

  1. Desenvolvimento da Tanatologia: estudos sobre a morte e o morrer

    Directory of Open Access Journals (Sweden)

    Maria Julia Kovács

    2008-12-01

    Full Text Available Este artigo discute os principais temas e pesquisas na área da Tanatologia, estudos sobre a morte e o morrer. São apresentados os autores pioneiros que escreveram as primeiras obras de sistematização da Tanatologia entre os quais: Herman Feifel, Robert Kastenbaum e Elizabeth Kübler-Ross, e os principais temas de estudo: luto, violência e guerra, a morte e a TV, cuidados a pacientes gravemente enfermos, além da formação de profissionais da área de saúde e educação para lidar com pessoas vivendo situações de perdas e morte. São feitas propostas de estudos para o futuro desenvolvimento da Tanatologia em nosso país.

  2. Desenvolvimento computacional aplicado a sistemas magnéticos

    OpenAIRE

    Villalba, Fernando David Céspedes; Cunha, Rafael Otoniel Ribeiro Rodrigues da

    2016-01-01

    Anais do V Encontro de Iniciação Científica e I Encontro Anual de Iniciação ao Desenvolvimento Tecnológico e Inovação – EICTI 2016 - 05 e 07 de outubro de 2016 – Sessão Ciências Exatas e da Terra A evolução tecnológica dos últimos anos tem trazido um novo universo em termos de materiais, principalmente na área de sólidos nanoestruturados, onde os efeitos quânticos assumem um importante papel. Este plano de pesquisa tem como objetivo geral estudar o comportamento de sistemas macro...

  3. Desenvolvimento rural, património e turismo

    OpenAIRE

    Condesso, Fernando; Universidad Tecnica de Lisboa

    2011-01-01

    Este estudo trata do desenvolvimento rural, com foco emquestões de turismo e património cultural,o conceito de turismoe considerações sobre as condições de sucesso. O turismo rural é hoje uma importantequestão global. Em um mundo quetende para a concentração da população, a ação conjuntaé necessária para fixar a população rural, para combater o abandono da paisagem humana tradicional,centrada na promoção de uma conomia baseada na dinâmica endógena eauto-centrada , Onde o turismoea afirmação d...

  4. DESENVOLVIMENTO DO POTENCIAL TECNOLÓGICO DE Casearia sylvestris

    Directory of Open Access Journals (Sweden)

    Lana Grasiela Alves Marques

    2013-12-01

    Full Text Available A análise prospectiva é uma importante ferramenta na identificação das oportunidades e das necessidades mais relevantes em Pesquisa e Desenvolvimento (P & D bem como das intervenções planejadas em sistemas de inovação. Este trabalho escolheu o gênero Casearia, epíteto sylvestris conhecida como "guaçatonga", para estudar seu potencial tecnológico, fazendo uso do Software Vantage Point - tratamento bibliométrico, geração dos dados quantitativos e identificação de indicadores científicos. Observou-se que as quantidades de publicações no Brasil (135 artigos indexados são bastante relevantes, embora indiquem um gargalo nos registros das patentes.

  5. As sementes geneticamente modificadas e o direito ao desenvolvimento

    Directory of Open Access Journals (Sweden)

    Milena Barbosa Melo

    2017-12-01

    Full Text Available O presente artigo apresenta como objeto de investigação a ligação entre os direitos da propriedade intelectual no contexto dos organismos geneticamente modificados (OGM´S. Objetivou-se, especificamente, responder inquietações acerca dos danos reais para os consumidores, bem como o lucro para as empresas multinacionais, sem desconsiderar, ainda, os efetivos danos ao meio ambiente e à saúde. Utilizou metodologia pautada em pesquisa bibliográfica e documental a partir do método hermenêutico fazendo uso da interpretação judicial-histórica. Conclui pela relevância da temática para efetivação do direito ao desenvolvimento, bem como pela urgência de uma regulamentação da biossegurança, de forma a permitir melhor sustentação aos OGM´s.

  6. TURISMO: FERRAMENTA DE DESENVOLVIMENTO DE REGIÕES

    OpenAIRE

    Michele Vasconcellos Chiattone; Eurico de Oliveira Santos; Maria Luiza Cardinale Baptista; Rafael Lima de Souza

    2015-01-01

    Esse artigo tem como foco a Mesorregião Metade Sul do estado do Rio Grande do Sul com suas regiões e microrregiões, descrevendo as cidades que as compõe com alguns de seus dados demográficos, econômicos e culturais; a estrutura de serviços para o turismo, os atrativos turísticos; e algumas rotas turísticas. Também enfoca o desenvolvimento do turismo na Metade Sul com os benefícios econômicos da atividade, o turismo rural e o enoturismo. O objetivo do estudo é discutir a importância do turismo...

  7. Desenvolvimento neuropsicomotor de lactentes desnutridos Neuropsychomotor development of malnourished babies

    Directory of Open Access Journals (Sweden)

    SS Mansur

    2006-01-01

    Full Text Available OBJETIVOS: O objetivo deste estudo foi analisar o desenvolvimento neuropsicomotor de lactentes com desnutrição leve e caracterizar seu perfil nutricional. MÉTODOS: A pesquisa foi do tipo transversal, numa população de 374 lactentes e amostra de 31 desnutridos leve, entre 7 e 24 meses de idade, matriculados em creches municipais. O estado nutricional foi identificado pelo critério de Gómez e caracterizado por um questionário. Para a avaliação neuropsicomotora utilizou-se a Escala de Desenvolvimento Psicomotor da Primeira Infância de Brunet e Lézine. RESULTADOS: Os principais resultados do questionário mostraram: infecções respiratórias (48,4%; diarréias (71,0%; pais em união estável (61,3%; pais com ensino fundamental incompleto (74,2% das mães, 83,8% dos pais; renda familiar de 1 a 3 salários-mínimos (80,6%; aleitamento materno satisfatório (67,7%; reação adversa a algum alimento (41,9%. Entre os dados neuropsicomotores, as médias das Idades de Desenvolvimento da Linguagem (14,45 meses e da Sociabilidade (14,74 meses foram as que obtiveram os valores mais abaixo da média da Idade Cronológica (16,41 meses. Todas as áreas avaliadas obtiveram Quocientes de Desenvolvimento dentro da normalidade, porém, as áreas da Linguagem e da Sociabilidade foram classificadas em nível "normal baixo" e as outras em nível "normal médio". CONCLUSÕES: A avaliação neuropsicomotora é instrumento fundamental na assistência ao lactente desnutrido, que tende a apresentar deficiências nas áreas da Linguagem e Sociabilidade, fornecendo subsídios para observar sua atuação exploratória, efeito de seu pensamento, e planejar o trabalho intervencionista.OBJECTIVE: The purpose of this study was to analyze the neuropsychomotor development of babies with slight malnutrition and to characterize their nutritional profile. METHOD: This was a cross-sectional survey on a population of 374 babies and a sample of 31 babies with slight

  8. Perspectivas de desenvolvimento e meio ambiente: o caso do Brasil

    OpenAIRE

    Cardoso, Fernando Henrique

    2014-01-01

    Introdução Nos últimos dez anos o desenvolvimento econômico do Brasil é frequentemente apontado como um caso êxito de industrialização e de mudança social ocorrido na periferia do sistema capitalista internacional. Não terá sido este o único caso. México, Argentina, Africa do Sul, Singapura, Coréia, índia etc, em graus variáveis e com padrões diversos de integração na economia mundial, são outros tantos exemplos. É certo que existe, nesta matéria, muitos equívocos. Mesmo considerando-se que e...

  9. INVESTIGATION OF PEM FUEL CELL FOR AUTOMOTIVE USE

    Directory of Open Access Journals (Sweden)

    A. K. M. Mohiuddin

    2015-11-01

    Full Text Available This paper provides a brief investigation on suitability of Proton-exchange  membrane fuel cells (PEMFCs as the source of power for transportation purposes. Hydrogen is an attractive alternative transportation fuel. It is the least polluting fuel that can be used in an internal combustion engine (ICE and it is widely available. If hydrogen is used in a fuel cell which converts the chemical energy of hydrogen into electricity, (NOx emissions are eliminated. The investigation was carried out on a  fuel cell car model by implementing polymer electrolyte membrane (PEM types of fuel cell as the source of power to propel the prototype car. This PEMFC has capability to propel the electric motor by converting chemical energy stored in hydrogen gas into useful electrical energy. PEM fuel cell alone is used as the power source for the electric motor without the aid of any other power source such as battery associated with it. Experimental investigations were carried out to investigate the characteristics of fuel cell used and the performance of the fuel cell car. Investigated papameters are the power it develops, voltage, current and speed it produces under different load conditions. KEYWORDS: fuel cell; automotive; proton exchange membrane; polymer electrolyte membrane; internal combustion engine

  10. Desenvolvimento, globalização e trabalho decente

    Directory of Open Access Journals (Sweden)

    Ronaldo Baltar

    Full Text Available O objetivo do artigo é discutir alguns desafios para o projeto brasileiro de desenvolvimento, baseado no consumo de massas dos três últimos Planos Plurianuais, que consiste na busca de equacionamento entre a ampliação da renda nacional através do trabalho, com aumento da empregabilidade e eliminação da precarização do trabalho. A pesquisa procura avaliar e comparar alguns indicadores sobre qualidade no emprego formal, tal como definido pela proposta da Organização Internacional do Trabalho (OIT para a Agenda do Trabalho Decente, em conjunto com dados que mostram a trajetória de inserção do Brasil no comércio internacional. O estudo levanta questões sobre as possibilidades de se garantir uma política de maior inserção no processo de globalização e, ao mesmo tempo, rever as consequências diretas da internacionalização da produção e do comércio sobre a qualidade do trabalho e a geração de renda. O texto conclui apontando que a formação de uma política de desenvolvimento centrada na ampliação do mercado interno, com propostas de expansão do consumo de massas, requer a definição de metas, não apenas de empregabilidade, mas voltadas à formação de empregos que atendam aos direitos fundamentais dos trabalhadores, seguindo os parâmetros da Agenda do Trabalho Decente.

  11. Governança municipal do desenvolvimento local:

    Directory of Open Access Journals (Sweden)

    Jean Carlos Machado Alves

    2009-12-01

    Full Text Available O presente trabalho desenvolve um estudo teórico-empírico, que descreve e analisa as possibilidades de desenvolvimento local dos municípios de Resende Costa e Ritápolis. Esses municípios localizam-se no Campo das Vertentes, em Minas Gerais, e têm possibilidade de novos negócios na expansão do comércio artesanal local, vinculada ao incremento do turismo regional. No entanto, o sistema produtivo de Resende Costa pode levar à falta de sustentabilidade e o potencial de Ritápolis sinaliza uma nova possibilidade de gestão sustentável. Constatou-se, no caso de Resende Costa, um sistema de produção que se desenvolveu ameaçando o saber artesanal e, em Ritápolis, ações de governança em prol de um desenvolvimento comunitário sustentável. Foram utilizadas pesquisas bibliográficas, documentais, coletas de dados secundários e observações dos pesquisadores na rede de organizacional produtiva artesanal desses municípios. A ausência de uma governança comunitária com a participação de todos os atores envolvidos pode gerar ações não intencionais que inviabilizam uma abordagem sustentável do sistema produtivo, principalmente artesanal, o que acarreta a perda na qualidade de vida, nas características e saberes socioculturais dos envolvidos nos sistemas produtivos locais.

  12. Application of a Coated Film Catalyst Layer Model to a High Temperature Polymer Electrolyte Membrane Fuel Cell with Low Catalyst Loading Produced by Reactive Spray Deposition Technology

    Directory of Open Access Journals (Sweden)

    Timothy D. Myles

    2015-10-01

    Full Text Available In this study, a semi-empirical model is presented that correlates to previously obtained experimental overpotential data for a high temperature polymer electrolyte membrane fuel cell (HT-PEMFC. The goal is to reinforce the understanding of the performance of the cell from a modeling perspective. The HT-PEMFC membrane electrode assemblies (MEAs were constructed utilizing an 85 wt. % phosphoric acid doped Advent TPS® membranes for the electrolyte and gas diffusion electrodes (GDEs manufactured by Reactive Spray Deposition Technology (RSDT. MEAs with varying ratios of PTFE binder to carbon support material (I/C ratio were manufactured and their performance at various operating temperatures was recorded. The semi-empirical model derivation was based on the coated film catalyst layer approach and was calibrated to the experimental data by a least squares method. The behavior of important physical parameters as a function of I/C ratio and operating temperature were explored.

  13. Elaboration, physical and electrochemical characterizations of CO tolerant PEMFC anode materials. Study of platinum-molybdenum and platinum-tungsten alloys and composites; Elaborations et caracterisations electrochimiques et physiques de materiaux d'anode de PEMFC peu sensibles a l'empoisonnement par CO: etude d'alliages et de composites a base de platine-molybdene et de platine-tungstene

    Energy Technology Data Exchange (ETDEWEB)

    Peyrelade, E.

    2005-06-15

    PEMFC development is hindered by the CO poisoning ability of the anode platinum catalyst. It has been previously shown that the oxidation potential of carbon monoxide adsorbed on the platinum atoms can be lowered using specific Pt based catalysts, either metallic alloys or composites. The objective is then to realize a catalyst for which the CO oxidation is compatible with the working potential of a PEMFC anode. In our approach, to enhance the CO tolerance of platinum based catalyst supported on carbon, we studied platinum-tungsten and platinum-molybdenum alloys and platinum-metal oxide materials (Pt-WO{sub x} and Pt-MoO{sub x}). The platinum based alloys demonstrate a small effect of the second metal towards the oxidation of carbon monoxide. The platinum composites show a better tolerance to carbon monoxide. Electrochemical studies on both Pt-MoO{sub x} and Pt-WO{sub x} demonstrate the ability of the metal-oxides to promote the ability of Pt to oxidize CO at low potentials. However, chrono-amperometric tests reveal a bigger influence of the tungsten oxide. Complex chemistry reactions on the molybdenum oxide surface make it more difficult to observe. (author)

  14. Synthesis and characterization of Nafion/TiO2 nanocomposite membrane for proton exchange membrane fuel cell.

    Science.gov (United States)

    Kim, Tae Young; Cho, Sung Yong

    2011-08-01

    In this study, the syntheses and characterizations of Nafion/TiO2 membranes for a proton exchange membrane fuel cell (PEMFC) were investigated. Porous TiO2 powders were synthesized using the sol-gel method; with Nafion/TiO2 nanocomposite membranes prepared using the casting method. An X-ray diffraction analysis demonstrated that the synthesized TiO2 had an anatase structure. The specific surface areas of the TiO2 and Nafion/TiO2 nanocomposite membrane were found to be 115.97 and 33.91 m2/g using a nitrogen adsorption analyzer. The energy dispersive spectra analysis indicated that the TiO2 particles were uniformly distributed in the nanocomposite membrane. The membrane electrode assembly prepared from the Nafion/TiO2 nanocomposite membrane gave the best PEMFC performance compared to the Nafion/P-25 and Nafion membranes.

  15. Optimization of fuel cell membrane electrode assemblies for transition metal ion-chelating ordered mesoporous carbon cathode catalysts

    Directory of Open Access Journals (Sweden)

    Johanna K. Dombrovskis

    2014-12-01

    Full Text Available Transition metal ion-chelating ordered mesoporous carbon (TM-OMC materials were recently shown to be efficient polymer electrolyte membrane fuel cell (PEMFC catalysts. The structure and properties of these catalysts are largely different from conventional catalyst materials, thus rendering membrane electrode assembly (MEA preparation parameters developed for conventional catalysts not useful for applications of TM-OMC catalysts. This necessitates development of a methodology to incorporate TM-OMC catalysts in the MEA. Here, an efficient method for MEA preparation using TM-OMC catalyst materials for PEMFC is developed including effects of catalyst/ionomer loading and catalyst/ionomer-mixing and application procedures. An optimized protocol for MEA preparation using TM-OMC catalysts is described.

  16. The Effect of Inhomogeneous Compression on Water Transport in the Cathode of a Proton Exchange Membrane Fuel Cell

    DEFF Research Database (Denmark)

    Olesen, Anders Christian; Berning, Torsten; Kær, Søren Knudsen

    2012-01-01

    diffusion layer, microporous layer, and catalyst layer, excluding the membrane and anode. In the porous media liquid water transport is described by the capillary pressure gradient, momentum loss via the Darcy-Forchheimer equation, and mass transfer between phases by a nonequilibrium phase change model...... variations affect gas and liquid water transport, and hence liquid water distribution and the risk of blocking active sites. Hence, water transport is studied under GDL compression in order to investigate the qualitative effects. Two simulation cases are compared; one with and one without compression.......A three-dimensional, multicomponent, two-fluid model developed in the commercial CFD package CFX 13 (ANSYS Inc.) is used to investigate the effect of porous media compression on water transport in a proton exchange membrane fuel cell (PEMFC). The PEMFC model only consist of the cathode channel, gas...

  17. Novel single-layer gas diffusion layer based on PTFE/carbon black composite for proton exchange membrane fuel cell

    Energy Technology Data Exchange (ETDEWEB)

    Chen-Yang, Y.W.; Hung, T.F.; Yang, F.L. [Department of Chemistry and Center for Nanotechnology, Chung Yuan Christian University, Chung-Li 32023 (China); Huang, J. [Yeu Ming Tai Chemical Industrial Co., Ltd, Taichung 40768 (China)

    2007-11-08

    A series of poly(tetrafluoroethylene)/carbon black composite-based single-layer gas diffusion layers (PTFE/CB-GDLs) for proton exchange membrane fuel cell (PEMFC) was successfully prepared from carbon black and un-sintered PTFE, which included powder resin and colloidal dispersion, by a simple inexpensive method. The scanning electron micrographs of PTFE/CB-GDLs indicated that the PTFE resins were homogeneously dispersed in the carbon black matrix and showed a microporous layer (MPL)-like structure. The as-prepared PTFE/CB-GDLs exhibited good mechanical property, high gas permeability, and sufficient water repellency. The best current density obtained from the PEMFC with the single-layer PTFE/CB-GDL was 1.27 and 0.42 A cm{sup -2} for H{sub 2}/O{sub 2} and H{sub 2}/air system, respectively. (author)

  18. Importance of Electrode Hot-Pressing Conditions for the Catalyst Performance of Proton Exchange Membrane Fuel Cells

    DEFF Research Database (Denmark)

    Andersen, Shuang Ma; Dhiman, Rajnish; Larsen, Mikkel Juul

    2015-01-01

    lamination have a great influence on the catalyst properties of a low-temperature PEMFC, especially on its durability. Lamination pressure, temperature and duration were systematically studied in relation to the electrochemical surface area, platinum dissolution, platinum particle size and electrode surface...... composition. The degradation of the platinum catalyst and polymer was analyzed in relation to the preparation conditions. An optimal electrode interface structure can improve Pt performance by (1) providing high platinum utilization; (2) decreasing platinum migration and coalescence; (3) reducing carbon......The catalyst performance in a proton exchange membrane fuel cell (PEMFC) depends on not only the choice of materials, but also on the electrode structure and in particular on the interface between the components. In this work, we demonstrate that the hot-pressing conditions used during electrode...

  19. Tutorial para o Desenvolvimento de Jogos 2D usando a Linguagem Java

    Directory of Open Access Journals (Sweden)

    Soraia Teixeira Barbosa

    2015-07-01

    Full Text Available Atualmente é grande o estudo e desenvolvimento de jogos eletrônicos tanto no meio acadêmico como fora dele. Entretanto o desenvolvimento do mesmo não é uma tarefa trivial. Este artigo mostra o desenvolvimento de um jogo computacional através de uma versão do conhecido jogo de arcade Space Invaders. O artigo proposto tem como objetivo mostrar os passos básicos para a construção de um jogo computacional em duas dimensões utilizando a linguagem de programação Java.

  20. Desenvolvimento da linguagem em crianças que permanecem no aleitamento materno

    OpenAIRE

    Dias, Natália da Costa

    2014-01-01

    O Desenvolvimento da Linguagem ocorre intensamente nos dois primeiros anos de vida e vários fatores genéticos e ambientais podem influenciar diretamente no processo de aprendizagem da linguagem de maneira sadia. Pouco se sabe sobe a influência do aleitamento materno por mais de dois anos, recomendação da Organização Mundial de Saúde (OMS), no desenvolvimento infantil. Alguns estudos apontam que a amamentação exclusiva (AM) por no mínimo seis meses influencia beneficamente no desenvolvimento i...

  1. Mobilidade e desenvolvimento local: o caso do concelho da Lousã

    OpenAIRE

    Ferreira, José Manuel Rodrigues

    2011-01-01

    O presente trabalho propõe-se divulgar a forma como a mobilidade pode influenciar o desenvolvimento local, nomeadamente no que ao concelho da Lousã diz respeito. A mobilidade, hoje mais que nunca, é um dos factores preponderantes no desenvolvimento. Também a sustentabilidade dessa mesma mobilidade está intrinsecamente ligada à sustentabilidade do desenvolvimento. Uma mobilidade sustentável, onde as deslocações se tornem aprazíveis, confortáveis, rápidas e seguras, onde as acessibilidades a...

  2. Elaboração e desenvolvimento de um website sobre o teste da linguinha

    OpenAIRE

    Martinelli, Victor Lopes de Castro; Martinelli, Roberta Lopes de Castro; Marchesan, Irene Queiroz; Berretin-Felix, Giédre; Souza, Simone do Rocio Senger de

    2017-01-01

    RESUMO Objetivo: desenvolver um website sobre o “Teste da Linguinha”. Métodos: pesquisa aplicada, baseada no desenvolvimento ativo de um website com a finalidade de disponibilizar informações sobre o Teste da Linguinha. O desenvolvimento desse estudo consistiu de 3 etapas: conceituação, desenvolvimento e implementação. Para a etapa de conceituação foi definido o público-alvo, o objetivo, a análise e a definição do conteúdo por meio de revisão de literatura sobre anquiloglossia, avaliação do...

  3. An experimental study on the cathode humidification and evaporative cooling of polymer electrolyte membrane fuel cells using direct water injection method at high current densities

    International Nuclear Information System (INIS)

    Hwang, Seong Hoon; Kim, Min Soo

    2016-01-01

    Highlights: • Proposal of a cathode humidification and evaporative cooling system for PEM fuel cells. • An external-mixing air-assist atomizer is used to produce a very fine water spray. • The system is effective in both cathode humidification and stack cooling. • Increased water flow rate improves stack performance and evaporative cooling capacity. • At a given water flow rate, lower stack temperatures cause greater humidification effect. - Abstract: Humidification and cooling are critical issues in enhancing the efficiency and durability of polymer electrolyte membrane fuel cells (PEMFCs). However, existing humidifiers and cooling systems have the disadvantage that they must be quite large to achieve adequate PEMFC performance. In this study, to eliminate the need for a bulky humidifier and to lighten the cooling load of PEMFCs, a cathode humidification and evaporative cooling system using an external-mixing air-assist atomizer was developed and its performance was investigated. The atomization performance of the nozzle was analyzed experimentally under various operating conditions with minimal changes in the system design. Experiments with a five-cell PEMFC stack with an active area of 250 cm 2 were carried out to analyze the effects of various parameters (such as the operating temperature, current density, and water injection flow rate) on the evaporation of injected water for humidification and cooling performances. The experimental results demonstrate that the direct water injection method proposed in this study is quite effective in cathode humidification and stack cooling in PEM fuel cells at high current densities. The stack performance was improved by humidification effect and the coolant temperature at the stack outlet decreased by evaporative cooling effect.

  4. Investigation of gas flow characteristics in proton exchange membrane fuel cell

    International Nuclear Information System (INIS)

    Kwac, Lee Ku; Kim, Hong Gun

    2008-01-01

    An investigation of electrochemical behavior of PEMFC (proton exchange membrane fuel cell) is performed by using a single-phase two-dimensional finite element analysis. Equations of current balance, mass balance, and momentum balance are implemented to simulate the behavior of PEMFC. The analysis results for the co-flow and counterflow mode of gas flow direction are examined in detail in order to compare how the gas flow direction affects quantitatively. The characteristics of internal properties, such as gas velocity distribution, mass fraction of the reactants, fraction of water and current density distribution in PEMFC are illustrated in the electrode and GDL (gas diffusion layer). It is found that the dry reactant gases can be well internally humidified and maintain high performance in the case of the counter-flow mode without external humidification while it is not advantageous for highly humidified or saturated reactant gases. It is also found that the co-flow mode improves the current density distribution with humidified normal condition compared to the counter-flow mode

  5. Performance of gas diffusion layer from coconut waste for proton exchange membrane fuel cell

    Science.gov (United States)

    Widodo, H.; Destyorini, F.; Insiyanda, D. R.; Subhan, A.

    2017-04-01

    The performance of Gas Diffusion Layer (GDL) synthesized from coconut waste. Gas Diffusion Layer (GDL), produced from coconut waste, as a part of Proton Exchange Membrane Fuel Cell (PEMFC) component, has been characterized. In order to know the performance, the commercial products were used as the remaining parts of PEMFC. The proposed GDL possesses 69% porosity for diffusion of Hydrogen fuel and Oxygen, as well as for transporting electron. With the electrical conductivity of 500 mS.cm-1, it also has hydrophobic properties, which is important to avoid the reaction with water, with the contact angle of 139°. The 5 × 5 cm2 GDL paper was co-assembled with the catalyst, Nafion membrane, bipolar plate, current collector, end plate to obtain single Stack PEMFC. The performance was examined by flowing fuel and gas with the flow rate of 500 and 1000 ml.min-1, respectively, and analyse the I-V polarization curve. The measurements were carried out at 30, 35, and 40°C for 5 cycles to ensure the repeatability. The results shows that the current density and the maximum power density reaches 203 mA.cm-2 and 143 mW.cm-2, respectively, with a given voltage 0.6 V, at 40°C.

  6. Niobized AISI 304 stainless steel bipolar plate for proton exchange membrane fuel cell

    Science.gov (United States)

    Wang, Lixia; Sun, Juncai; Li, Pengbin; Jing, Bo; Li, Song; Wen, Zhongsheng; Ji, Shijun

    2012-06-01

    AISI 304 stainless steel (SS) has been niobized by a plasma surface diffusion alloying method. A 3 μm niobized layer with dominant niobium elements has been formed on the 304 SS surface and the performances of the niobized 304 SS has been examined and evaluated as bipolar plate for proton exchange membrane fuel cell (PEMFC). Results show that the average contact angle with water for the niobized 304 SS is about 90.4°, demonstrating better hydrophobicity as compared with the untreated 304 SS (68.1°). The corrosion resistance of the 304 SS is considerably improved by the niobized layer with the corrosion current densities decreased at 0.2 and 0.4 μA cm-2 in simulated PEMFC anode purged with hydrogen and the cathode purged with air condition (0.05 M H2SO4 + 2 ppm F- solution at 70 °C), respectively. The interfacial contact resistance (ICR) for the as-prepared niobized 304 SS is 10.53 mΩ cm2 at the compaction of 140 N cm-2. Furthermore, after 4 h potentiostatic tests, the niobizied specimens exhibit much lower ICR than that for the untreated ones. Thus, the niobized layer can act as a conductively protective layer of the 304 SS bipolar plate for PEMFC.

  7. A Transient Model for Fuel Cell Cathode-Water Propagation Behavior inside a Cathode after a Step Potential

    Directory of Open Access Journals (Sweden)

    Der-Sheng Chan

    2010-04-01

    Full Text Available Most of the voltage losses of proton exchange membrane fuel cells (PEMFC are due to the sluggish kinetics of oxygen reduction on the cathode and the low oxygen diffusion rate inside the flooded cathode. To simulate the transient flooding in the cathode of a PEMFC, a transient model was developed. This model includes the material conservation of oxygen, vapor, water inside the gas diffusion layer (GDL and micro-porous layer (MPL, and the electrode kinetics in the cathode catalyst layer (CL. The variation of hydrophobicity of each layer generated a wicking effect that moves water from one layer to the other. Since the GDL, MPL, and CL are made of composite materials with different hydrophilic and hydrophobic properties, a linear function of saturation was used to calculate the wetting contact angle of these composite materials. The balance among capillary force, gas/liquid pressure, and velocity of water in each layer was considered. Therefore, the dynamic behavior of PEMFC, with saturation transportation taken into account, was obtained in this study. A step change of the cell voltage was used to illustrate the transient phenomena of output current, water movement, and diffusion of oxygen and water vapor across the entire cathode.

  8. Degradation of graphene coated copper in simulated proton exchange membrane fuel cell environment: Electrochemical impedance spectroscopy study

    Science.gov (United States)

    Ren, Y. J.; Anisur, M. R.; Qiu, W.; He, J. J.; Al-Saadi, S.; Singh Raman, R. K.

    2017-09-01

    Metallic materials are most suitable for bipolar plates of proton exchange membrane fuel cell (PEMFC) because they possess the required mechanical strength, durability, gas impermeability, acceptable cost and are suitable for mass production. However, metallic bipolar plates are prone to corrosion or they can passivate under PEMFC environment and interrupt the fuel cell operation. Therefore, it is highly attractive to develop corrosion resistance coating that is also highly conductive. Graphene fits these criteria. Graphene coating is developed on copper by chemical vapor deposition (CVD) with an aim to improving corrosion resistance of copper under PEMFC condition. The Raman Spectroscopy shows the graphene coating to be multilayered. The electrochemical degradation of graphene coated copper is investigated by electrochemical impedance spectroscopy (EIS) in 0.5 M H2SO4 solution at room temperature. After exposure to the electrolyte for up to 720 h, the charge transfer resistance (Rt) of the graphene coated copper is ∼3 times greater than that of the bare copper, indicating graphene coatings could improve the corrosion resistance of copper bipolar plates.

  9. Functionalized single-walled carbon nanotube-based fuel cell benchmarked against US DOE 2017 technical targets.

    Science.gov (United States)

    Jha, Neetu; Ramesh, Palanisamy; Bekyarova, Elena; Tian, Xiaojuan; Wang, Feihu; Itkis, Mikhail E; Haddon, Robert C

    2013-01-01

    Chemically modified single-walled carbon nanotubes (SWNTs) with varying degrees of functionalization were utilized for the fabrication of SWNT thin film catalyst support layers (CSLs) in polymer electrolyte membrane fuel cells (PEMFCs), which were suitable for benchmarking against the US DOE 2017 targets. Use of the optimum level of SWNT -COOH functionality allowed the construction of a prototype SWNT-based PEMFC with total Pt loading of 0.06 mg(Pt)/cm²--well below the value of 0.125 mg(Pt)/cm² set as the US DOE 2017 technical target for total Pt group metals (PGM) loading. This prototype PEMFC also approaches the technical target for the total Pt content per kW of power (<0.125 g(PGM)/kW) at cell potential 0.65 V: a value of 0.15 g(Pt)/kW was achieved at 80°C/22 psig testing conditions, which was further reduced to 0.12 g(Pt)/kW at 35 psig back pressure.

  10. Structural Dynamics and Activity of Nanocatalysts Inside Fuel Cells by in-operando Atomic Pair Distribution Studies

    Science.gov (United States)

    Prasai, Binay

    We present the results from a study aimed at clarifying the relationship between the atomic structure and activity of nanocatalysts for chemical reactions driving fuel cells, such as the oxygen reduction reaction (ORR). Using in-operando high-energy X-ray diffraction we tracked the evolution of the atomic structure and activity of noble metal-transition metal(NM-TM) nanocatalysts for ORR as they function at the cathode of a fully operational proton exchange membrane fuel cell (PEMFC). Data were analyzed in terms of atomic pair distribution functions and compared to the current output of the PEMFC, which was also recorded during the experiments. The comparison revealed that under actual operating conditions, NM-TM nanocatalysts can undergo structural changes that differ significantly in both length-scale and dynamics and so can suffer losses in their ORR activity that differ significantly in both character and magnitude. Therefore, we argue that strategies for reducing ORR activity losses should implement steps for achieving control not only over the length but also over the time-scale of the structural changes of NM-TM NPs that indeed occur during PEMFC operation.

  11. Effect of various concentration of sulfuric acid for Nafion membrane activation on the performance of fuel cell

    Science.gov (United States)

    Pujiastuti, Sri; Onggo, Holia

    2016-02-01

    This work proposes an activation treatment to Nafion 117 membrane with sulfuric acid in various concentrations. The main goal of this study is to increase the Nafion 117 membrane performance, which is determined by proton number in the membrane and membrane performance in Polymer Electrolyte Membrane Fuel Cell (PEMFC). This work was developed using sulfuric acids in four different concentrations: 1, 2, 3, and 4 M. The surface morphology and functional groups of activated membranes were studied using Scanning Electron Microscope and Fourier Transform Infrared, respectively. The proton number absorbed in membranes was observed by gravimetric measurements. The performances of activated membranes in PEMFC were studied by single cell measurements with H2/O2 operation. The experimental results showed that activation of Nafion membrane did not change its surface morphology and functional groups. The proton number increased when the concentration of sulfuric acid is increased from 1 to 3 M and from 1 to 4 M. On the other hand, there is no significant increase when the concentration of sulfuric acid was increased from 1 to 2 M. Similar trends were observed when testing activated membrane performance in PEMFC, especially for current density at 0.6 V and maximum power. It is assumed that there is a correlation between the increase of sulfuric acid concentration in activation process with the increase of proton number in the membrane that are available for facilitating of transfer protons from the anode to the cathode.

  12. Iridium-decorated palladium-platinum core-shell catalysts for oxygen reduction reaction in proton exchange membrane fuel cell.

    Science.gov (United States)

    Wang, Chen-Hao; Hsu, Hsin-Cheng; Wang, Kai-Ching

    2014-08-01

    Carbon-supported Pt, Pd, Pd-Pt core-shell (Pt(shell)-Pd(core)/C) and Ir-decorated Pd-Pt core-shell (Ir-decorated Pt(shell)-Pd(core)/C) catalysts were synthesized, and their physical properties, electrochemical behaviors, oxygen reduction reaction (ORR) characteristics and proton exchange membrane fuel cell (PEMFC) performances were investigated herein. From the XRD patterns and TEM images, Ir-decorated Pt(shell)-Pd(core)/C has been confirmed that Pt was deposited on the Pd nanoparticle which had the core-shell structure. Ir-decorated Pt(shell)-Pd(core)/C has more positive OH reduction peak than Pt/C, which is beneficial to weaken the binding energy of Pt-OH during the ORR. Thus, Ir-decorated Pt(shell)-Pd(core)/C has higher ORR activity than Pt/C. The maximum power density of H2-O2 PEMFC using Ir-decorated Pt(shell)-Pd(core)/C is 792.2 mW cm(-2) at 70°C, which is 24% higher than that using Pt/C. The single-cell accelerated degradation test of PEMFC using Ir-decorated Pt(shell)-Pd(core)/C shows good durability by the potential cycling of 40,000 cycles. This study concludes that Ir-decorated Pt(shell)-Pd(core)/C has the low Pt content, but it can facilitate the low-cost and high-efficient PEMFC. Copyright © 2013 Elsevier Inc. All rights reserved.

  13. Habilidades do desenvolvimento de prematuros Development abilities in preterm

    Directory of Open Access Journals (Sweden)

    Dionísia Aparecida Cusin Lamônica

    2009-01-01

    Full Text Available OBJETIVO: verificar o desempenho de habilidades do desenvolvimento linguístico, cognitivo, motor, de autocuidados e socialização em crianças prematuras. MÉTODOS: participaram 30 crianças nascidas prematuras, de ambos os sexos de seis a 24 meses. Os procedimentos de avaliação constaram de uma entrevista de anamnese e da aplicação do Inventário Portage Operacionalizado (IPO (Wilhiams & Aiello, 2001. As crianças foram divididas em dois grupos, conforme a faixa etária, para análise estatística dos dados, considerando as idades de seis a 11 meses e de 12 a 24 meses. A análise dos dados foi realizada por meio da aplicação do teste Manny-Whitney comparando os valores obtidos no grupo de crianças prematuras com escores previstos para crianças típicas. RESULTADOS: os resultados indicam que a área mais defasada do grupo na faixa etária de seis a 12 meses foi à linguística e autocuidados e na faixa etária de 12 a 24 meses as áreas mais defasadas foram linguística, cognitiva e de autocuidados. CONCLUSÃO: ressalta-se a necessidade de um acompanhamento rigoroso de recém-nascidos prematuros, por meio do desenvolvimento de programas de acompanhamento e por uma equipe multidisciplinar para promover a detecção e intervenção precoce, minimizando assim o impacto de problemas no desenvolvimento global destas crianças.PURPOSE: to check the performance of the linguistic, cognitive, motor, self-care and socialization development abilities in premature children. METHODS: 30 premature children participated, of both genders, from 6 to 24 months. The evaluation procedures consisted of an anamnesis interview and Operating Portage Inventory (OPI (Wilhiams & Aiello, 2001 application. The children were divided in two groups, according to age group, for statistical data analysis, considering the age groups from 6 to 11 months and from 12 to 24 months. Data analysis was accomplished through Manny-Whitney test application, comparing the values

  14. Use of Electrochemical Impedance Spectroscopy for the Evaluation of Performance of PEM Fuel Cells Based on Carbon Cloth Gas Diffusion Electrodes

    Directory of Open Access Journals (Sweden)

    Saverio Latorrata

    2018-01-01

    Full Text Available Polymer electrolyte membrane fuel cells (PEMFCs have attracted great attention in the last two decades as valuable alternative energy generators because of their high efficiencies and low or null pollutant emissions. In the present work, two gas diffusion electrodes (GDEs for PEMFCs were prepared by using an ink containing carbon-supported platinum in the catalytic phase which was sprayed onto a carbon cloth substrate. Two aerograph nozzles, with different sizes, were used. The prepared GDEs were assembled into a fuel cell lab prototype with commercial electrolyte and bipolar plates and tested alternately as anode and cathode. Polarization measurements and electrochemical impedance spectroscopy (EIS were performed on the running hydrogen-fed PEMFC from open circuit voltage to high current density. Experimental impedance spectra were fitted with an equivalent circuit model by using ZView software which allowed to get crucial parameters for the evaluation of fuel cell performance, such as ohmic resistance, charge transfer, and mass transfer resistance, whose trends have been studied as a function of the applied current density.

  15. Speeding the transition: Designing a fuel-cell hypercar

    Energy Technology Data Exchange (ETDEWEB)

    Williams, B.D.; Moore, T.C.; Lovins, A.B. [Rocky Mountain Inst., Snowmass, CO (United States). Hypercar Center

    1997-12-31

    A rapid transformation now underway in automotive technology could accelerate the transition to transportation powered by fuel cells. Ultralight, advanced-composite, low-drag, hybrid-electric hypercars--using combustion engines--could be three- to fourfold more efficient and one or two orders of magnitude cleaner than today`s cars, yet equally safe, sporty, desirable, and (probably) affordable. Further, important manufacturing advantages--including low tooling and equipment costs, greater mechanical simplicity, autobody parts consolidation, shorter product cycles, and reduced assembly effort and space--permit a free-market commercialization strategy. This paper discusses a conceptual hypercar powered by a proton-exchange-membrane fuel cell (PEMFC). It outlines the implications of platform physics and component selection for the vehicle`s mass budget and performance. The high fuel-to-traction conversion efficiency of the hypercar platform could help automakers overcome the Achilles` heel of hydrogen-powered vehicles: onboard storage. Moreover, because hypercars would require significantly less tractive power, and even less fuel-cell power, they could adopt fuel cells earlier, before fuel cells` specific cost, mass, and volume have fully matured. In the meantime, commercialization in buildings can help prepare fuel cells for hypercars. The promising performance of hydrogen-fueled PEMFC hypercars suggests important opportunities in infrastructure development for direct-hydrogen vehicles.

  16. Estratégias de Governo para Promover o Desenvolvimento de Software Livre

    OpenAIRE

    Borges, Clairmont; Instituto de Informática, Universidade Federal do Rio Grande do Sul; Geyer, Cláudio F. R.; Instituto de Informática, Universidade Federal do Rio Grande do Sul

    2003-01-01

    Este artigo apresenta nossa visão sobre estratégias de governo para promover o desenvolvimento de Software Livre. Esta visão é baseada nas nossas atividades de pesquisa e nas experiências práticas em trabalhar com desenvolvimento de Software Livre. Este artigo também descreve suscintamente porque é importante usar Software Livre e como o seu modelo econômico parece funcionar.

  17. PROPOSTA TEÓRICO-CONCEITUAL DE DESENVOLVIMENTO EM ARRANJOS PRODUTIVOS LOCAIS

    Directory of Open Access Journals (Sweden)

    Adriana Valélia Saraceni

    2013-04-01

    Full Text Available O objetivo central deste trabalho foi evidenciar algumas ferramentas para o desenvolvimento da inovação e verificar a relação com a configuração do desenvolvimento em Arranjos Produtivos Locais (APLs. Esta pesquisa pode ser considerada como exploratória e descritiva, pois envolve levantamento bibliográfico e análise de exemplos que estimulem a compreensão. Estudos sobre ferramentas de inovação tecnológica e referencias do desenvolvimento de ecossistemas industriais, foram utilizados buscando demonstrar uma proposta teórico-conceitual de integração das ferramentas. Por meio do resultado obtido com a aplicação da metodologia e do referencial teórico, verificou-se que aplicação das ferramentas de inovação tecnológica e a operacionalização com a implantação de métodos e ações cooperadas, tende a fortalecer o desempenho do processo de inovação do arranjo produtivo. A aplicação do conceito de ecologia industrial no desenvolvimento ambientalmente sustentável do aglomerado tende a fortalecer não só o desenvolvimento do APL, como também o desenvolvimento econômico e regional.

  18. Desenvolvimento de Jogos Utilizando XNA: um Exemplo com o Jogo SpaceX

    Directory of Open Access Journals (Sweden)

    Joni Pereira de Pinho Rodrigues da Silva

    2015-07-01

    Full Text Available A área de jogos eletrônicos tem crescido cada vez mais. Podese, nos dias atuais, encontrar jogos em diversos dispositivos: computadores pessoais, consoles domésticos e dispositivos móveis. O desenvolvimento de um jogo não é uma tarefa fácil, pois envolve diversas áreas de conhecimento e também diversas subáreas da computação. A área de desenvolvimento de jogos desperta muita curiosidade e interesse em muitos programadores, entretanto a maioria das instituições de ensino superior com cursos na área de computação não apresentam o foco ou disciplinas específicas para o desenvolvimento de jogos, principalmente em Curso de Sistemas de Informação. Esta foi uma das motivações para o desenvolvimento deste trabalho. Este artigo apresenta o framework XNA e as suas principais funcionalidades para desenvolvimento de jogos eletrônicos interativos. Como resultado e exemplificação o artigo também apresenta o desenvolvimento de um jogo 2D, chamado SpaceX.

  19. A Novel Hybrid Actuator Driven Magnetically in the Bi-Cell PEM Fuel Cell Stack

    Directory of Open Access Journals (Sweden)

    Hsiaokang Ma

    2017-10-01

    Full Text Available This study develops an air breathing pump driven by a piezoelectric actuator for a proton exchange membrane fuel cell (PEMFC stack. Permanent magnets are combined with a piezoelectric actuator to drive three air breathing pumps using magnetic force. This design enables the pump to provide a sufficient amount of air simultaneously to six cathode flow field plates in a stack of three “bi-cell PZTmag–PEMFCs”. When both the PZTmag and the PDMSmag had a magnet with a 6-mm diameter and 1-mm thickness, a maximum amplitude of 87 μm was generated at 0.03 W of power under operating conditions of 70 Hz and 40 V. In computational fluid dynamics (CFD, when the nozzle and the diffuser of an air breathing pump have an aspect ratio of 13.13, air flow distributes uniformly inside the pump, thus allowing for uniform transmission of oxygen to the membrane electrode assembly. This aspect ratio was applied to the bi-cell PZTmag–PEMFC stack and yielded a maximum net power flux of 0.1925 W·cm−2, 20% higher than that reported in a previous study (Ma, 2013, with 68% and 76% less volume and weight, respectively.

  20. O desenvolvimento regional brasileiro ainda em questão

    Directory of Open Access Journals (Sweden)

    Liana Carleial

    2014-01-01

    Full Text Available O artigo argumenta que a questão regional brasileira, instalada nos anos sessenta do século passado e, com igual período, de políticas de desenvolvimento regional não conseguiu reduzir de forma importante as desigualdades regionais, e só fortalece o padrão de divisão inter-regional definido na metade do século XX. O agravante é que a questão regional está fora das pautas política, econômica empresarial e acadêmica brasileiras. No presente ensaio, considera-se , no entanto, que o conjunto de investimentos em infraestrutura e em setores estratégicos da indústria fora do eixo Rio-São Paulo, poderiam conduzir a um adensamento das estruturas produtivas das regiões mais empobrecidas e permitir uma nova dinâmica regional que altere o atual padrão de divisão inter-regional do trabalho no Brasil. É surpreendente que não conseguimos “engatar” as regiões mais empobrecidas na dinâmica nacional apoiada pelo BNDES.

  1. LEVEL UP! DESENVOLVIMENTO COGNITIVO, APRENDIZAGEM ENATIVA E VIDEOGAMES

    Directory of Open Access Journals (Sweden)

    Carlos Baum

    Full Text Available Resumo Os videogames são frequentemente acusados de serem prejudiciais à saúde. Sua operatividade colocaria o jogador em uma série de rotinas irracionais, muito próximas a uma relação estímulo-resposta. Sugerimos que tal posição limita as possibilidades de relação entre o videogame e a aprendizagem e está baseada em uma imagem teleológica do desenvolvimento da cognição que toma o aprender como uma caminhada em direção à racionalidade lógica. O presente artigo parte da descrição do aprendizado de um dos autores analisada a partir da retórica procedural com um jogo eletrônico para propor um modo de compreender a ação com o videogame, que convoca a uma constante recomposição do sujeito que joga e do jogo. A teoria da enação, por sua vez, apresenta proposições que sustentam uma modalidade de conhecimento operativo e incorporado, mais próximo da experiência com os videogames.

  2. DESENVOLVIMENTO DE ROBÔ DE SUMÔ MICROCONTROLADO POR MSP430

    Directory of Open Access Journals (Sweden)

    Magno Melo

    2017-02-01

    Full Text Available Este artigo apresenta a pesquisa e definição dos componentes necessários ao desenvolvimento de um robô autônomo a ser utilizado em competição de sumô de robôs. Este tipo de equipamento, também conhecido como robô segue faixa, será desenvolvido com o objetivo de introdução à robótica, bem como do estudo do funcionamento e aplicabilidade do microcontrolador MSP430, o qual será o componente responsável pela automação deste robô. Assim, a partir desta definição, faz-se necessária a especificação dos demais componentes integrantes do equipamento (chassi, meio de locomoção, motores, sensores e alimentação de tal forma que o robô possa desempenhar adequadamente as tarefas para os quais o mesmo foi idealizado.

  3. Desenvolvimento docente nos cursos de medicina: um campo fecundo

    Directory of Open Access Journals (Sweden)

    Cinthia Rêgo

    Full Text Available Foi feita uma revisão sistemática da literatura (1997-2007, no âmbito da formação docente, em currículos médicos orientados pela aprendizagem baseada em problemas, por meio de busca, identificação, seleção e análise de estudos nas bases Scielo, Lilacs, Cochrane, Medline, Ibesc, Pubmed e Eric com os descritores faculty OR faculty medical or staff development and education, medical or education, medical undergraduate or medical, schools and pbl. Os estudos analisados se agruparam em três eixos norteadores, que delinearam aplicações práticas para um programa de desenvolvimento docente eficiente: gestão participativa, maior investimento nos docentes, elaboração e aplicação de programas de educação continuada, permanente, com foco na construção dos conhecimentos, habilidades e atitudes.

  4. Desenvolvimento Sustentável - Cultura e Cidadania

    Directory of Open Access Journals (Sweden)

    Silvio Pinto Ferreira

    2011-02-01

    Full Text Available O presente artigo tem como objetivo apresentar a trajetória da valorização da cultura no contexto do crescimento e desenvolvimento sustentável desde o encontro das Nações Unidas no Brasil, que ficou conhecido como ECO-92 e, como a cultura teve sua inserção nos comprometimentos apresentados nas Agendas 21 Global e Local tomando, neste caso, o exemplo da cidade de São Paulo. Hoje, mais do que nunca, os países estão percebendo que o reconhecimento da identidade cultural de sua sociedade é elemento fundamental para qualquer tipo de transformação econômica, social ou ambiental, uma vez que a integração destas esferas só será possível quando se olhar para a necessidade da inclusão e da prática da cidadania, para que então se possa respeitar a diversidade.  Este artigo aponta também para a importância da tradição cultural dos povos, sociedades, grupos e comunidades e como estes podem se beneficiar das políticas públicas que poderão ser criadas para garantir a liberdade da sociedade em manifestar e expressar sua cultura em tempos de globalização.

  5. Desenvolvimento inicial de cultivares de videira em Muzambinho-MG

    Directory of Open Access Journals (Sweden)

    Lucas Eduardo de Oliveira Aparecido

    2014-03-01

    Full Text Available Objetivou-se avaliar o desenvolvimento agronômico inicial de cultivares de videira, nas condições da região do sul de Minas Gerais, no Brasil. O experimento foi conduzido no setor de Fruticultura do IFSULDEMINAS – Campus Muzambinho. Os materiais vegetativos utilizados foram mudas nuas, enxertadas sobre o porta-enxerto ‘1103 Paulsen’ pelo método de enxertia de mesa. Os tratamentos foram oito cultivares de videira rústica (Vistis labrusca L.: Isabel (1, Concord (2, Bordô (3, Isabel precoce (4, BRS Cora (5, BRS Rúbea (6, BRS Violeta (7 e Niágara Rosada (8. O delineamento foi em blocos ao acaso, com três repetições e oito tratamentos, e cada parcela composta por cinco plantas, totalizando 120 plantas. Em relação ao diâmetro de enxerto e porta-enxerto, as cultivares não demonstraram diferença significativa em condições iniciais. Para as variáveis altura de plantas e massa verde, a cultivar Niágara Rosada destacou-se dentre as demais.

  6. Use of multi-functional flexible micro-sensors for in situ measurement of temperature, voltage and fuel flow in a proton exchange membrane fuel cell.

    Science.gov (United States)

    Lee, Chi-Yuan; Chan, Pin-Cheng; Lee, Chung-Ju

    2010-01-01

    Temperature, voltage and fuel flow distribution all contribute considerably to fuel cell performance. Conventional methods cannot accurately determine parameter changes inside a fuel cell. This investigation developed flexible and multi-functional micro sensors on a 40 μm-thick stainless steel foil substrate by using micro-electro-mechanical systems (MEMS) and embedded them in a proton exchange membrane fuel cell (PEMFC) to measure the temperature, voltage and flow. Users can monitor and control in situ the temperature, voltage and fuel flow distribution in the cell. Thereby, both fuel cell performance and lifetime can be increased.

  7. Environmental analysis of the proton exchange membrane fuel cell on the subject of life cycle assessment

    International Nuclear Information System (INIS)

    Fukurozaki, Sandra Harumi

    2006-01-01

    The energy is the fuel of growth and an essential requirement for the socioeconomic development. However, the current production model is based on fossil fuels, considered as threat to man and nature. As for, the relating to the human activities and their effects on the environment, they are handled by the implementation of a more rigid model of environmental control and the mobilization of the society in favor of technologies with less energy impact. In view of this scenario, the Proton Exchange Membrane Fuel Cell - PEMFC has been recognized as a key for the vital need of a clean and efficient energy. Considering the conventional power generation system, their advantages during usage configure its application as an ideal option for several utilities, especially in the mobile sector. Even though, the focus on several environmental evaluations in energy systems is referred back to the initial stage of it use, the employment relating to production of the system and to final destination should be considered, since these also present impacts. In the case of PEMFC, their previous and subsequent phases of use are issues related to the platinum catalysts, which indicates an environmental importance that cannot be overlooked. In this sense, the Life Cycle Assessment has been used to understand and to question the risks and opportunities that are associated to certain product, starting from a systemic concept of their relationships with the environment. It is precisely in this context that the present research intends to present its major contribution, starting from an exploratory study towards the its objectives to provide an environmental analysis of such technology linked to post stage of powder-use of the membrane electrode assembly - MEA, concerning the platinum catalysts, on the subject of Life Cycle Assessment - LCA. To attain such aim, the relationships between energy, environment and development are presented and discussed, as well as, the Fuel Cell technology and

  8. Membranas catiônicas a base de poli(indeno) sulfonado/PVA para uso como eletrólito em célula a combustível tipo PEMFC

    OpenAIRE

    Fábio José Bento Brum

    2013-01-01

    Neste trabalho foram preparadas membranas de poli(indeno) sulfonado (PIndS) com poli(álcool vinílico) (PVA), na forma de rede de polímeros semi-interpenetrantes (semi-IPN), para uso em células a combustível como eletrólito polimérico (PEMFC). Para tal, foram sintetizados polímeros hidrocarbônicos a base de indeno, estireno, limoneno e 5-etilideno-2-norborneno, via mecanismo catiônico, utilizando AlCl3 como catalisador visando à obtenção de um polímero precursor para uso como polímero eletróli...

  9. Research at the service of energy transition - Hydrogen and fuel cells

    International Nuclear Information System (INIS)

    Bodineau, Luc; Antoine, Loic; Tonnet, Nicolas; Theobald, Olivier; Tappero, Denis

    2018-03-01

    This brochure brings together 22 hydrogen-energy and fuel cell projects selected and supported by the French agency of environment and energy management (Ademe) since 2012 through its call for research projects TITEC (industrial tests and transfers in real conditions) and Sustainable Energy: 1 - BHYKE: electric-hydrogen bike experiment; 2 - CHYMENE: innovative hydrogen compressor for mobile applications; 3 - COMBIPOL 3: bipolar plates assembly technology and gasketing process for PEMFC; 4 - CRONOS: high temperature SOFC for domestic micro-cogeneration; 5 - EPILOG: natural gas fuel cell on the way to commercialization; 6 - EXALAME: polyfunctional catalytic complexes for membranes-electrodes assembly without Nafion for PEMFC; 7 - HYCABIOME: H 2 and CO 2 conversion by biological methanation; 8 - HYLOAD: hydrogen-fueled airport vehicle experiment with on-site supply chain; 9 - HYSPSC: Pressurized hydrogen without Compressor; 10 - HYWAY: hydrogen mobility cluster demonstrator (electric-powered Kangoo cars fleet with range extender) at Lyon and Grenoble; 11 - MHYEL: Pre-industrialization of composite hybrid Membranes for PEM electrolyzer; 12 - NAVHYBUS: Design and experimentation of an electric-hydrogen river shuttle for passengers transportation at Nantes; 13 - PACMONT: fuel cells integration and adaptation for high mountain and polar applications; 14 - PREMHYOME: fabrication process of hybrid membranes for PEMFC; 15 - PRODIG: lifetime prediction and warranty for fuel cell systems; 16 - REHYDRO: fuel cell integration in the circular economy principle; 17 - SPHYNX and Co: optimizing renewable energy integration and self-consumption in buildings; 18 - THEMIS: design and experimentation of an autonomous on-site power supply system; 19 - VABHYOGAZ: biogas valorization through renewable hydrogen generation, design and experimentation of a 5 Nm 3 /h demonstrator at a waste disposal site; 20 - VALORPAC: Integration and experimentation of a high-temperature SOFC system that use

  10. Determinantes do desenvolvimento do setor agropecuário nos municípios

    Directory of Open Access Journals (Sweden)

    Caio César de Medeiros Costa

    2013-06-01

    Full Text Available Dada a importância do setor agropecuário para a economia brasileira, é fundamental conhecer os fatores determinantes do desenvolvimento agropecuário em seus municípios. Sob a luz de referencial teórico que aborda questões relacionadas aos fatores determinantes do desenvolvimento agropecuário e do desenvolvimento econômico local, neste estudo fez-se uso das metodologias de análise multivariada conhecidas como análise fatorial e análise de cluster. Utilizou-se o estado de Minas Gerais como recorte analítico. Foram selecionadas 22 variáveis para cada município, representando diferentes dimensões do desenvolvimento, visando verificar quais os fatores determinantes do desenvolvimento agropecuário. Após a análise fatorial, optou-se pela extração de seis fatores com raiz característica maior do que um e que respondem, em conjunto, por 62,25% da variância total dos dados: desenvolvimento econômico, investimento público, qualidade de vida, condições da atividade agropecuária, condições de meio ambiente e consumo, e condições de financiamento. Pela análise de cluster, foram criados cinco grupos, de acordo com o desempenho dos membros nos fatores. Os resultados corroboram os apontamentos literários em quase sua totalidade e, além disso, destaca-se e discute-se a existência de um ciclo positivo gerado pelo incremento dos fatores determinantes do desenvolvimento agropecuário e pelas vantagens competitivas. Neste estudo, aponta-se a importância do investimento público na promoção do desenvolvimento, reforçando o proposto por trabalhos anteriores de que o Estado desempenha papel fundamental para garantir condições que propiciem o desenvolvimento do setor agropecuário. Outra constatação factível é a de que fatores isolados, tais como as boas condições da agricultura e do meio ambiente, não são capazes de propiciar desenvolvimento para o setor nos municípios mineiros.

  11. Advances in PEM fuel cells with CFD techniques

    Energy Technology Data Exchange (ETDEWEB)

    Robalinho, Eric; Cunha, Edgar Ferrari da; Zararya, Ahmed; Linardi, Marcelo [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)], Email: eric@ipen.br; Cekinski, Efrain [Instituto de Pesquisas Tecnologicas (IPT), Sao Paulo, SP (Brazil)

    2010-07-01

    This paper presents some applications of computational fluid dynamics techniques in the optimization of Proton Exchange Membrane Fuel Cell (PEMFC) designs. The results concern: modeling of gas distribution channels, the study for both porous anode and cathode and the three-dimensional modeling of a partial geometry layer containing catalytic Gas Diffusion Layers (GDL) and membrane. Numerical results of the simulations of graphite plates flow channels, using ethanol as fuel, are also presented. Some experimental results are compared to the corresponding numerical ones for several cases, demonstrating the importance and usefulness of this computational tool. (author)

  12. Characterising of solid state electrochemical cells under operation

    DEFF Research Database (Denmark)

    Holtappels, Peter

    2014-01-01

    Compared to significant progress in PEMFC especially regarding the utilization of complex fuels such as methanol significant progress has been made by applying spectroscopic / differential IR and spectrometric techniques to working fuel cells, the processes in solid state high temperature....... This relates to interrelation between NOx/ O2 on cathodes but also to sulfur and carbon exposure at the anode. Past and recent activities on SOFC anodes and cathodes will be presented as well as perspectives and gaps discussed for these systems. Especially interaction between sulfur interactions with solids...

  13. Towards Extrusion of Ionomers to Process Fuel Cell Membranes

    Directory of Open Access Journals (Sweden)

    Jean-Yves Sanchez

    2011-07-01

    Full Text Available While Proton Exchange Membrane Fuel Cell (PEMFC membranes are currently prepared by film casting, this paper demonstrates the feasibility of extrusion, a solvent-free alternative process. Thanks to water-soluble process-aid plasticizers, duly selected, it was possible to extrude acidic and alkaline polysulfone ionomers. Additionally, the feasibility to extrude composites was demonstrated. The impact of the plasticizers on the melt viscosity was investigated. Following the extrusion, the plasticizers were fully removed in water. The extrusion was found to impact neither on the ionomer chains, nor on the performances of the membrane. This environmentally friendly process was successfully validated for a variety of high performance ionomers.

  14. Analysis of the behavior and degradation in proton exchange membrane fuel cells with a dead-ended anode

    Science.gov (United States)

    Yu, Jianliang; Jiang, Zuwei; Hou, Ming; Liang, Dong; Xiao, Yu; Dou, Meiling; Shao, Zhigang; Yi, Baolian

    2014-01-01

    Proton exchange membrane fuel cells (PEMFCs) with a dead-ended anode (DEA) can obtain high hydrogen utilization by a comparatively simple system. Nevertheless, the accumulation of the nitrogen and the water in the anode channels can lead to a local fuel starvation, which degrades the performance and durability of PEMFCs. In this paper, the behaviors of PEMFCs with a DEA are explored experimentally by detecting the current distribution and the local potentials. The results indicate that the current distribution is uneven during the DEA operation. The local current firstly decreases at the region near the anode outlet, and then extends to the inlet region along the channels with time. The complete fuel starvation near the anode outlet leads to a high local potential and carbon corrosion on the cathode side. The SEM images of the cathode electrode reveal that the significant thickness reduction and the collapse of the electrode's porous structure happen in the cathode catalyst layer, leading to the irreversible decline of the performance. The comparison of the experiments with different oxidants and fuels reveals that the nitrogen crossover from cathode to anode is the dominant factor on the performance decline under the DEA operations.

  15. Hierarchical nanostructured hollow spherical carbon with mesoporous shell as a unique cathode catalyst support in proton exchange membrane fuel cell.

    Science.gov (United States)

    Fang, Baizeng; Kim, Jung Ho; Kim, Minsik; Kim, Minwoo; Yu, Jong-Sung

    2009-03-07

    Hierarchical nanostructured spherical carbon with hollow macroporous core in combination with mesoporous shell has been explored to support Pt cathode catalyst with high metal loading in proton exchange membrane fuel cell (PEMFC). The hollow core-mesoporous shell carbon (HCMSC) has unique structural characteristics such as large specific surface area and mesoporous volume, ensuring uniform dispersion of the supported high loading (60 wt%) Pt nanoparticles with small particle size, and well-developed three-dimensionally interconnected hierarchical porosity network, facilitating fast mass transport. The HCMSC-supported Pt(60 wt%) cathode catalyst has demonstrated markedly enhanced catalytic activity toward oxygen reduction and greatly improved PEMFC polarization performance compared with carbon black Vulcan XC-72 (VC)-supported ones. Furthermore, the HCMSC-supported Pt(40 wt%) or Pt(60 wt%) outperforms the HCMSC-supported Pt(20 wt%) even at a low catalyst loading of 0.2 mg Pt cm(-2) in the cathode, which is completely different from the VC-supported Pt catalysts. The capability of supporting high loading Pt is supposed to accelerate the commercialization of PEMFC due to the anticipated significant reduction in the amount of catalyst support required, diffusion layer thickness and fabricating cost of the supported Pt catalyst electrode.

  16. Dynamic environmental transmission electron microscopy observation of platinum electrode catalyst deactivation in a proton-exchange-membrane fuel cell.

    Science.gov (United States)

    Yoshida, Kenta; Xudong, Zhang; Bright, Alexander N; Saitoh, Koh; Tanaka, Nobuo

    2013-02-15

    Spherical-aberration-corrected environmental transmission electron microscopy (AC-ETEM) was applied to study the catalytic activity of platinum/amorphous carbon electrode catalysts in proton-exchange-membrane fuel cells (PEMFCs). These electrode catalysts were characterized in different atmospheres, such as hydrogen and air, and a conventional high vacuum of 10(-5) Pa. A high-speed charge coupled device camera was used to capture real-time movies to dynamically study the diffusion and reconstruction of nanoparticles with an information transfer down to 0.1 nm, a time resolution below 0.2 s and an acceleration voltage of 300 kV. With such high spatial and time resolution, AC-ETEM permits the visualization of surface-atom behaviour that dominates the coalescence and surface-reconstruction processes of the nanoparticles. To contribute to the development of robust PEMFC platinum/amorphous carbon electrode catalysts, the change in the specific surface area of platinum particles was evaluated in hydrogen and air atmospheres. The deactivation of such catalysts during cycle operation is a serious problem that must be resolved for the practical use of PEMFCs in real vehicles. In this paper, the mechanism for the deactivation of platinum/amorphous carbon electrode catalysts is discussed using the decay rate of the specific surface area of platinum particles, measured first in a vacuum and then in hydrogen and air atmospheres for comparison.

  17. Effects of propylene, methyl methacrylate and isopropanol poisoning on spatial performance of a proton exchange membrane fuel cell

    Science.gov (United States)

    Reshetenko, Tatyana V.; St-Pierre, Jean

    2018-02-01

    This paper studies the effects of propylene, methyl methacrylate (MMA) and isopropanol (IPA) in air on the spatial performance of proton exchange membrane fuel cells (PEMFCs). The introduction of 100 ppm C3H6 into the oxidant stream resulted in a performance decrease of 130 mV at 1.0 A cm-2, whereas 20 ppm MMA caused a voltage loss of 80 mV. A moderate performance decline of 60 mV was detected in the presence of 5.3ṡ103 ppm IPA in air. Spatial electrochemical impedance spectroscopy (EIS) data showed an increase in charge and mass transfer resistances under exposure to C3H6 and MMA, although IPA did not affect the impedance. The observed PEMFC performances, local current redistributions and EIS data can be explained by the adsorption of contaminants on the Pt surface, their subsequent transformations, and their impacts on the electrochemical surface area and oxygen reduction mechanism. It was assumed that the studied contaminants were oxidized mainly to CO2 via electrochemical and chemical pathways under the operating conditions and at the cathode potential. Self-recovery of PEMFC performance was observed for each contaminant after halting its introduction into the air. Possible contaminant oxidation/reduction mechanisms and their correlations with spatial performance and EIS are presented and discussed.

  18. Analysis of the system efficiency of an intermediate temperature proton exchange membrane fuel cell at elevated temperature and relative humidity conditions

    International Nuclear Information System (INIS)

    Jeon, Seung Won; Cha, Dowon; Kim, Hyung Soon; Kim, Yongchan

    2016-01-01

    Highlights: • System efficiency of PEMFC is evaluated at elevated temperature and humidity. • Operating parameters are optimized using response surface methodology. • The optimal operating parameters are T = 90.6 °C, RH = 100.0%, and ζ = 2.07. • The power output and system efficiency are 1.28 W and 15.8% at the optimum. • The system efficiency can be effectively improved by increasing relative humidity. - Abstract: Humidification of the membrane is very important in a proton exchange membrane fuel cell (PEMFC), to maintain high ionic conductivity. At an elevated temperature, a large amount of thermal energy is required for humidification because of the exponentially increased saturation vapor pressure. In this study, the system efficiency of a PEMFC was evaluated by considering the heat required for preheating/humidification and compression work. Three-dimensional steady-state simulations were conducted using Fluent 14 to simulate the electrochemical reactions. The operating conditions were optimized using response surface methodology by considering both the fuel cell output and system efficiency. In addition, the effects of operating parameters such as the temperature, relative humidity, and stoichiometric ratio were investigated. The system efficiency can be improved more effectively by increasing relative humidity rather than increasing operating temperature because the ionic conductivity of the membrane was strongly influenced by the relative humidity.

  19. Design and Implementation of 8051 Single-Chip Microcontroller for Stationary 1.0 kW PEM Fuel Cell System

    Directory of Open Access Journals (Sweden)

    Pei-Hsing Huang

    2014-01-01

    Full Text Available Proton exchange membrane fuel cells (PEMFCs have attracted significant interest as a potential green energy source. However, if the performance of such systems is to be enhanced, appropriate control strategies must be applied. Accordingly, the present study proposes a sophisticated control system for a 1.0 kW PEMFC system comprising a fuel cell stack, an auxiliary power supply, a DC-DC buck converter, and a DC-AC inverter. The control system is implemented using an 8051 single-chip microcontroller and is designed to optimize the system performance and safety in both the startup phase and the long-term operation phase. The major features of the proposed control system are described and the circuit diagrams required for its implementation introduced. In addition, the touch-sensitive, intuitive human-machine interface is introduced and typical screens are presented. Finally, the electrical characteristics of the PEMFC system are briefly examined. Overall, the results confirm that the single-chip microcontroller presented in this study has significant potential for commercialization in the near future.

  20. Fuel cell technology for cogeneration systems. Symposium. Proceedings; Brennstoffzellen - Technologie fuer Blockheizkraftwerke. Symposium. Dokumentation

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2001-07-01

    This proceedings volume contains 11 papers on the following subject: Competence network 'Fuel Cells' in Nordrhein-Westfalen (D. Stolten, Juelich Research Center); Fuel cells in stationary applications (B. Hoehlein, Juelich Research Center); Functional principles of energy conversion in fuel cells (W. Schnurnberger, DLR); Low-temperature fuel cells AFC, PEMFC, PAFC (M. Waidhas, Siemens); High-temperature fuel cells - SOFC, MCFC (D. Stolten); Power plant options - natural gas, hydrogen, etc. (R. Wurster, Ludwig-Boelkow-Systemtechnik); Fuel cell supply (A. Heizel, ISE); Hydrogen-fuelled cogeneration units (G. Gummert Hamburg Gas Consult); SOFC high-temperature fuel cells for domestic power supply (R. Diethelm, Sulzer-Hexis); PEFC low-temperature fuel cells for domestic power supply (K. Klinder, Vaillant); Fuel cells, a chance for local utilities (B. Vogel, WINGAS). [German] Dieser Tagungsband enthaelt 11 Beitraege zu folgenden Themen: Kompetenznetzwerk Brennstoffzelle in NRW (D. Stolten, Forschungszentrum Juelich); Brennstoffzellen in der stationaeren Anwendung (B. Hoehlein, Forschungszentrum Juelich); Funktionsprinzipien der Energieumwandlung in Brennstoffzellen (W. Schnurnberger, DLR); Niedertemperaturbrennstoffzellen - AFC, PEMFC, PAFC (M. Waidhas, Siemens); Hochtemperaturbrennstoffzellen - SOFC, MCFC (D. Stolten); Kraftstoffoptionen- Erdgas, Wasserstoff u.a. (R. Wurster, Ludwig-Boelkow-Systemtechnik); Brennstoffbereitstellung (A. Heinzel, ISE); Wasserstoffbetriebene BHKW (G. Gummert Hamburg Gas Consult); Hochtemperaturbrennstoffzelle SOFC fuer die Hausenergieversorgung (R. Diethelm, Sulzer-Hexis); Niedertemperaturbrennstoffzelle PEFC fuer die Hausenergieversorgung (K. Klinder, Vaillant); Brennstoffzelle als Chance fuer lokale EVUs (B. Vogel, WINGAS).