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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. 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)

  3. 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)

  4. 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

  5. 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

  6. Technology watch of polymer fuel cells (PEMFC) 2012; Teknikbevakning av polymera braensleceller (PEMFC) 2012

    Energy Technology Data Exchange (ETDEWEB)

    Wreland Lindstroem, Rakel; Lindbergh, Goeran

    2013-03-15

    The commercial development of the PEMFC has made strong progress in recent years. Between 2010 and 2011, the number of units shipped increased by 87%. The forecast for 2012 is a further tripling of the number of units delivered to about 71000 during the year. Sales of stationary units are increasing, and they account for a third of the number of units and almost half of the rated power with a total of over 20 MW. The increase consists of a few large units and a continued growth in small combined heat and power plant for residential use (micro-CHP). The increase is also reflected by the Japanese catalyst manufacturer Tanaka which increased its sales of catalysts for fuel cells by 67% in 2011. The number of units for transport is still small but is believed to take over the market when fuel cell vehicles enter the market around the 2015. Combined heat and power plant for residential, micro-CHP, has gained ground in Japan. The systems under the name ENE-FARM is based on natural gas reformed and used in a PEMFC. The demand increased even further after the tsunami and nuclear disaster in 2011. The global market for micro-CHP, which is dominated by the Japanese market, grew by 38%. Since 2010, the Japanese system has improved and obtained higher electrical efficiency and become 20% cheaper. The interest in micro-CHP increase also in other countries. A Germany program had in June 2012 260 systems installed, and projected 550 systems at the end of 2013. A European program called ene.field brings together European producers and users in 12 member states to test various fuel cell technologies in around 1000 installations in buildings. In Korea, 350 micro-CHP systems have been produced in 2012. The large amount of hydrogen produced as a by-product in the chemical industry has recently been highlighted. The hydrogen is today typically burned to provide heat, but calculations show that if the gas instead is used in fuel cells the industry's electricity costs could be

  7. Cathode degradation of the polymer electrolyte membrane fuel cell (PEMFC)

    International Nuclear Information System (INIS)

    Morphological changes occurring in membrane electrode assemblies (MEAs) of polymer electrolyte membrane fuel cells (PEMFC's) were monitored using scanning microscopy (SEM) during the course of 600 hours testing of hydrogen/air polymer electrolyte fuel cells (PEFCs). The microstructural study suggests a structural change caused by loss of the recast ionomer could result in deterioration of the integrity of the electrode, a drop in both ionic and electronic conductivities, loss of platinum particle clusters (for carbon support), and increased resistance within the interfacial zone of the membrane and catalyst layer.(author)

  8. Particle Swarm Optimization based predictive control of Proton Exchange Membrane Fuel Cell (PEMFC)

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Proton Exchange Membrane Fuel Cells (PEMFCs) are the main focus of their current development as power sources because they are capable of higher power density and faster start-up than other fuel cells. The humidification system and output performance of PEMFC stack are briefly analyzed. Predictive control of PEMFC based on Support Vector Regression Machine (SVRM) is presented and the SVRM is constructed. The processing plant is modelled on SVRM and the predictive control law is obtained by using Particle Swarm Optimization (PSO). The simulation and the results showed that the SVRM and the PSO receding optimization applied to the PEMFC predictive control yielded good performance.

  9. Multi-dimensional modeling of CO poisoning effects on proton exchange membrane fuel cells (PEMFCs)

    International Nuclear Information System (INIS)

    Carbon monoxide (CO), which is preferentially absorbed on the platinum catalyst layer of a proton exchange membrane fuel cell (PEMFC), is extremely detrimental to cell performance. Essentially, the carbon monoxide absorption diminishes the cell's performance by blocking and reducing the number of catalyst sites available for the hydrogen oxidation reaction. In order to obtain a full understanding of CO poisoning characteristics and remediate CO-poisoned PEMFCs, a CO poisoning numerical model is developed and incorporated into a fully three-dimensional electrochemical and transport coupled PEMFC model. By performing CFD numerical simulations, this paper clearly demonstrates the CO poisoning mechanisms and characteristics of PEMFCs. The predictive capability for CO poisoning effects enables us to find major contributors to CO tolerance in a PEMFC and thus successfully integrate CO-resistant fuel cell systems

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

    International Nuclear Information System (INIS)

    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)

    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. Experiments of a 30kW 90 cell PEMFC under transportation load cycle constraints

    OpenAIRE

    Harel, F.; DE-BERNARDINIS, A; GIRARDOT,L; Francois, X.; Candusso, D.; Hissel, D.; Coquery, G.

    2008-01-01

    This paper presents a synthesis of the experimental process and results performed on a 30kW pilot PEMFC stack. The tests have been realized at the FC testing platform (FCLAB) in Belfort. The fuel cell (FC) stack is a prototype composed of 90 cells fed by hydrogen and compressed air. The tests are performed in the framework of the SPACT-80 research project, financed by the French Ministry of research, which concerns the study, the realization and the testing of an 80kW PEMFC generator for tran...

  13. Performance analysis of an integrated biomass gasification and PEMFC (proton exchange membrane fuel cell) system: Hydrogen and power generation

    International Nuclear Information System (INIS)

    The PEMFC (proton exchange membrane fuel cell) is expected to play a significant role in next-generation energy systems. Because most hydrogen that is used as a fuel for PEMFCs is derived from the reforming of natural gas, the use of renewable energy sources such as biomass to produce this hydrogen offers a promising alternative. This study is focused on the performance analysis of an integrated biomass gasification and PEMFC system. The combined heat and power generation output of this integrated system is designed for residential applications, taking into account thermal and electrical demands. A flowsheet model of the integrated PEMFC system is developed and employed to analyze its performance with respect to various key operating parameters. A purification process consisting of a water–gas shift reactor and a preferential oxidation reactor is also necessary in order to reduce the concentration of CO in the synthesis gas to below 10 ppm for subsequent use in the PEMFC. The effect of load level on the performance of the PEMFC system is investigated. Based on an electrical load of 5 kW, it is found that the electrical efficiency of the PEMFC integrated system is 22%, and, when waste heat recovery is considered, the total efficiency of the PEMFC system is 51%. - Highlights: • Performance of a biomass gasification and PEMFC integrated system is analyzed. • A flowsheet model of the PEMFC integrated system is developed. • Effect of biomass sources and key parameters on hydrogen and power generation is presented. • The PEMFC integrated system is designed for small-scale power demand. • Effect of load changes on the performance of PEMFC is investigated

  14. Modeling and Optimization of PEMFC Systems and its Application to Direct Hydrogen 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 extensively developed in recent decades. Besides the fuel cell stack, air and fuel control, and thermal and water management are major challenges in the fuel cell vehicle development. The air supply system can have a major impact on overall system efficiency. In this report, a fuel cell system model for optimizing system operating conditions was developed which includes the tran...

  15. Carbon composite bipolar plate for high-temperature proton exchange membrane fuel cells (HT-PEMFCs)

    Science.gov (United States)

    Lee, Dongyoung; Lee, Dai Gil

    2016-09-01

    A carbon/epoxy composite bipolar plate is an ideal substitute for the brittle graphite bipolar plate for lightweight proton exchange membrane fuel cells (PEMFCs) because of its high specific strength and stiffness. However, conventional carbon/epoxy composite bipolar plates are not applicable for high-temperature PEMFCs (HT-PEMFCs) because these systems are operated at higher temperatures than the glass transition temperatures of conventional epoxies. Therefore, in this study, a cyanate ester-modified epoxy is adopted for the development of a carbon composite bipolar plate for HT-PEMFCs. The composite bipolar plate with exposed surface carbon fibers is produced without any surface treatments or coatings to increase the productivity and is integrated with a silicone gasket to reduce the assembly cost. The developed carbon composite bipolar plate exhibits not only superior electrical properties but also high thermo-mechanical properties. In addition, a unit cell test is performed, and the results are compared with those of the conventional graphite bipolar plate.

  16. A multi-timescale modeling methodology for PEMFC performance and durability in a virtual fuel cell car

    OpenAIRE

    Mayur, Manik; Strahl, Stephan; Husar, Attila; Bessler, Wolfgang G.

    2015-01-01

    The durability of polymer electrolyte membrane fuel cells (PEMFC) is governed by a nonlinear cou-pling between system demand, component behavior, and physicochemical degradation mechanisms, occurring on timescales from the sub-second to the thousand-hour. We present a simulation methodol-ogy for assessing performance and durability of a PEMFC under automotive driving cycles. The simu-lation framework consists of (a) a fuel cell car model converting velocity to cell power demand, (b) a 2D mult...

  17. Effect of different fuel options on performance of high-temperature PEMFC (proton exchange membrane fuel cell) systems

    International Nuclear Information System (INIS)

    High-temperature proton exchange membrane fuel cells (HT-PEMFCs) have received substantial attention due to their high CO (carbon monoxide) tolerance and simplified water management. The hydrogen and CO fractions affect the HT-PEMFC performance and different fuel sources for hydrogen production result in different product gas compositions. Therefore, the aim of this study is to investigate the theoretical performance of HT-PEMFCs fueled by the reformate gas derived from various fuel options (i.e., methane, methanol, ethanol, and glycerol). Effects of fuel types and CO poisoning on the HT-PEMFC performance are analyzed. Furthermore, the necessity of a water-gas shift (WGS) reactor as a CO removal unit for pretreating the reformate gas is investigated for each fuel type. The methane steam reforming shows the highest possibility of CO formation, whereas the methanol steam reforming produces the lowest quantity of CO in the reformate gas. The methane fuel processing gives the maximum fraction of hydrogen (≈0.79) when the WGS reactor is included. The most suitable fuel is the one with the lowest CO poisoning effect and the maximum fuel cell performance. It is found that the HT-PEMFC system fueled by methanol without the WGS reactor and methane with WGS reactor shows the highest system efficiency (≈50%). - Highlights: • Performance of HT-PEMFC run on different fuel options is theoretically investigated. • Glycerol, methanol, ethanol and methane are hydrogen sources for the HT-PEMFC system. • Effect of CO poisoning on the HT-PEMFC performance is taken into account. • The suitable fuel for HT-PEMFC system is identified regarding the system efficiency

  18. 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)

  19. 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.

  20. PEMFC Optimization Strategy with Auxiliary Power Source in Fuel Cell Hybrid Vehicle

    Directory of Open Access Journals (Sweden)

    Tinton Dwi Atmaja

    2012-02-01

    Full Text Available Page HeaderOpen Journal SystemsJournal HelpUser You are logged in as...aulia My Journals My Profile Log Out Log Out as UserNotifications View (27 new ManageJournal Content SearchBrowse By Issue By Author By Title Other JournalsFont SizeMake font size smaller Make font size default Make font size largerInformation For Readers For Authors For LibrariansKeywords CBPNN Displacement FLC LQG/LTR Mixed PMA Ventilation bottom shear stress direct multiple shooting effective fuzzy logic geoelectrical method hourly irregular wave missile trajectory panoramic image predator-prey systems seawater intrusion segmentation structure development pattern terminal bunt manoeuvre Home About User Home Search Current Archives ##Editorial Board##Home > Vol 23, No 1 (2012 > AtmajaPEMFC Optimization Strategy with Auxiliary Power Source in Fuel Cell Hybrid VehicleTinton Dwi Atmaja, Amin AminAbstractone of the present-day implementation of fuel cell is acting as main power source in Fuel Cell Hybrid Vehicle (FCHV. This paper proposes some strategies to optimize the performance of Polymer Electrolyte Membrane Fuel Cell (PEMFC implanted with auxiliary power source to construct a proper FCHV hybridization. The strategies consist of the most updated optimization method determined from three point of view i.e. Energy Storage System (ESS, hybridization topology and control system analysis. The goal of these strategies is to achieve an optimum hybridization with long lifetime, low cost, high efficiency, and hydrogen consumption rate improvement. The energy storage system strategy considers battery, supercapacitor, and high-speed flywheel as the most promising alternative auxiliary power source. The hybridization topology strategy analyzes the using of multiple storage devices injected with electronic components to bear a higher fuel economy and cost saving. The control system strategy employs nonlinear control system to optimize the ripple factor of the voltage and the current

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

    International Nuclear Information System (INIS)

    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)

  2. Using adaptive neuro fuzzy inference system (ANFIS) for proton exchange membrane fuel cell (PEMFC) performance modeling

    Energy Technology Data Exchange (ETDEWEB)

    Rezazadeh, S.; Mirzaee, I. [Urmia Univ., Urmia (Iran, Islamic Republic of); Mehrabi, M. [University of Pretoria, Pretoria (South Africa)

    2012-11-15

    In this paper, an adaptive neuro fuzzy inference system (ANFIS) is used for modeling proton exchange membrane fuel cell (PEMFC) performance using some numerically investigated and compared with those to experimental results for training and test data. In this way, current density I (A/cm{sup 2}) is modeled to the variation of pressure at the cathode side P{sup C} (atm), voltage V (V), membrane thickness (mm), Anode transfer coefficient {alpha}{sup an}, relative humidity of inlet fuel RH{sup a} and relative humidity of inlet air RH{sup c} which are defined as input (design) variables. Then, we divided these data into train and test sections to do modeling. We instructed ANFIS network by 80% of numerical validated data. 20% of primary data which had been considered for testing the appropriateness of the models was entered ANFIS network models and results were compared by three statistical criterions. Considering the results, it is obvious that our proposed modeling by ANFIS is efficient and valid and it can be expanded for more general states.

  3. Effect of modified flow field on non-isothermal transport characteristics and cell performance of a PEMFC

    International Nuclear Information System (INIS)

    Highlights: • Jet-type and trapping effects enhance non-isothermal transport in fuel channel. • Rectangular obstacle opposite or staggered with protuberant layer raises reaction. • Tapered flow of rib opposite or staggered with protuberant layer raises reaction. • Tapered flow of ribs opposite the protuberant layer gets the best cell performance. • Maximum increase rate in PEMFC performance is 8% for the modified flow fields. - Abstract: This study analyzes how modified flow field affects non-isothermal transport characteristics and cell performance of the proton exchange membrane fuel cell (PEMFC) by the finite-volume SIMPLE-C method coupled with preconditioned conjugate gradient methods. The modified flow field is obtained by rectangular obstacles opposite or staggered with the protuberant catalyst layer surface or narrowed flow channel, with ribs opposite or staggered with the protuberant catalyst layer surface. This study also considered the effect of liquid water formation on the fluid flow field. The cell performance of the modified flow field is compared with that of the conventional flow channel. The comparison result demonstrates that the narrowed flow channel with ribs opposite the protuberant catalyst layer surface has the best increase rate in cell performance. The increase rate is approximately 8%

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

    International Nuclear Information System (INIS)

    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 cm2 MEA area. The MEA cost production for MEAs of 247.86 cm2, that can generate 1 kilowatt of energy was estimated to US$ 7,744.14 including cost of equipment, materials and labor. (author)

  5. 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 overpotent......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...

  6. 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)

  7. Gas diffusion electrode based on electrospun Pani/CNF nanofibers hybrid for proton exchange membrane fuel cells (PEMFC) applications

    International Nuclear Information System (INIS)

    A novel hybrid system has been investigated based on polyaniline/carbon nanofiber (Pani/CNF) electrospun nanofibers for modification of gas diffusion electrode (GDE) in proton exchange membrane fuel cells (PEMFC). Pani/CNF hybrid nanofibers were synthesized directly on carbon paper by electrospinning method. For preparation of catalyst ink, 20 wt.% Pt/C electrocatalyst with a platinum loading of 0.4 mg cm−2 was prepared by polyol technique. SEM studies applied for morphological study of the modified GDE with hybrid nanofibers. This technique indicated that the electrospun nanofibers had a diameter of roughly 100 nm. XRD patterns also showed that the average size of Pt nanoparticles was about 2 nm. Subsequently, comparison of the hybrid electrode electrochemical behavior and 20 wt.% Pt/C commercial one was studied by cyclic voltammetry experiment. The electrochemical data indicated that the hybrid electrode exhibited higher current density (about 15 mA cm−2) and ESA (160 m2 gr−1) than commercial Pt/C with amount of about 10 mA cm−2 and 114 m2 gr−1, respectively. The results herein demonstrate that Pani/CNF nanofibers can be used as a good alternative electrode material for PEMFCs

  8. Gas diffusion electrode based on electrospun Pani/CNF nanofibers hybrid for proton exchange membrane fuel cells (PEMFC) applications

    Energy Technology Data Exchange (ETDEWEB)

    Hezarjaribi, M.; Jahanshahi, M., E-mail: mjahan@nit.ac.ir; Rahimpour, A.; Yaldagard, M.

    2014-03-01

    A novel hybrid system has been investigated based on polyaniline/carbon nanofiber (Pani/CNF) electrospun nanofibers for modification of gas diffusion electrode (GDE) in proton exchange membrane fuel cells (PEMFC). Pani/CNF hybrid nanofibers were synthesized directly on carbon paper by electrospinning method. For preparation of catalyst ink, 20 wt.% Pt/C electrocatalyst with a platinum loading of 0.4 mg cm{sup −2} was prepared by polyol technique. SEM studies applied for morphological study of the modified GDE with hybrid nanofibers. This technique indicated that the electrospun nanofibers had a diameter of roughly 100 nm. XRD patterns also showed that the average size of Pt nanoparticles was about 2 nm. Subsequently, comparison of the hybrid electrode electrochemical behavior and 20 wt.% Pt/C commercial one was studied by cyclic voltammetry experiment. The electrochemical data indicated that the hybrid electrode exhibited higher current density (about 15 mA cm{sup −2}) and ESA (160 m{sup 2} gr{sup −1}) than commercial Pt/C with amount of about 10 mA cm{sup −2} and 114 m{sup 2} gr{sup −1}, respectively. The results herein demonstrate that Pani/CNF nanofibers can be used as a good alternative electrode material for PEMFCs.

  9. 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)

  10. Low platinum, high limiting current density of the PEMFC (proton exchange membrane fuel cell) based on multilayer cathode catalyst approach

    International Nuclear Information System (INIS)

    Novel multilayer cathode electrodes structures for PEMFC (proton exchange membrane fuel cell) based on sputtering technique were developed to provide high performance with low loading Pt of 0.05 mg/cm² compared to the standard MEA (membrane electrode assembly) cathode (∼0.2–0.3 mg/cm²). Different configurations of cathode catalyst layer were made by altering Pt and CN (Carbon–Nafion) ink carefully prepared on gas diffusion layer containing MPL (micro porous layer). The performances of PEMFC containing the multilayer electrodes were compared based on their measured polarization curves. Higher limiting current densities were achieved compared to standard MEA with platinum loading of 0.2 mg/cm² both at the cathode and the anode sides. Limiting current densities over 1.1 A/cm2, 1.2 A/cm2 and 1.4 A/cm2 were reached whereas maximum powers were in the range of 500 mW/cm² at 600 mW/cm². The good performances obtained can be due to the structural improvement which has contributed to a better catalyst utilization compared to conventional methods. A CN loading inferior to 0.24 mg/cm² between each layer is preferred for multilayer electrode. - Highlights: • Multilayer cathode of PEM fuel cell. • Enhanced performances with carbon–Nafion layer of PEM fuel cell. • Effect of the number of Pt sputtered layers on cell performance. • Increased power densities achieved. • Increased limiting current densities achieved

  11. 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.

  12. A three-dimensional numerical investigation of trapezoid baffles effect on non-isothermal reactant transport and cell net power in a PEMFC

    International Nuclear Information System (INIS)

    Highlights: • We study how angle and height of trapezoid baffle affect PEMFC net power. • The jet-type, trapping, and blockage effects augment non-isothermal transport in flow channel. • Greater angles and heights of trapezoid baffles provide more reactant to the catalyst layer. • Baffles of 1.5 mm and 90° fully block flow channel to show bad heat transfer and large pressure drop. • Maximum enhancement of cell net power is 90% with baffles of 60° angle and 1.125 mm height. - Abstract: The present study performed a three-dimensional numerical simulation to observe how trapezoid baffles affect non-isothermal reactant transports and cell net power in the proton exchange membrane fuel cell (PEMFC) by the SIMPLE-C method. The geometric parameters of trapezoid baffles installed in the gas channel employed in this study include the angle and height with the same gas diffusion and catalyst layers to realize the cell net power considering the effect of liquid water formation on the fluid flow field. The cell net power is adopted to evaluate the real enhancement of cell performance due to the additional pumping power induced by the pressure loss through the PEMFC. The results illustrated that compared with traditional gas channel without baffles, the novel gas channel with trapezoid baffles, whose angle is 60° and height is 1.125 mm, enhances the cell net power best by approximately 90% among all trapezoid baffle designs

  13. 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)

  14. Thermoplastic composite bipolar plates for polymer electrolyte membrane fuel cells (PEMFC). Paper no. IGEC-1-089

    International Nuclear Information System (INIS)

    Polymer electrolyte membrane fuel cells (PEMFC) are one significant component of the Hydrogen Economy. In order to make fuel cells economically feasible, processing and material cost need to be reduced. This reduction extends to the cost associated with bipolar plates. In an effort to produce functional bipolar plates at a competitive cost thermoplastic composite materials were extruded and injection molded, combining commercial materials such as polypropylene, carbon fiber, Vulcan carbon black, and acetylene carbon black. Two trials were executed. Trial 1 is a twenty sample experimental design and Trial 2 consists of different filler loadings with filler ratio 1:1:1. Thermal gravimetric analysis (TGA) was used to determine the actual filler loading following processing. Two methods of measuring electrical conductivity were investigated for Trial 1. Using method 1 a filler loading of 35 wt% and filler ratio of 1:1:1 reveals the best conductivity of 155 S/m. Method 2 has a maximum conductivity of 38 S/m and is achieved with a 32 wt% of only Vulcan carbon black. In Trial 2 a significant portion of the percolation curve for the filler ratio 1:1:1 is obtained. (author)

  15. Hydrogen PEMFCs prepared by microfabrication

    Energy Technology Data Exchange (ETDEWEB)

    Gruber, D.; Ponath, N.; Mueller, J. [Hamburg Univ. of Technology (Germany). Dept. of Micro Systems Technology

    2005-07-01

    In this work, microfabrication of polymer electrolyte membrane fuel cells (PEMFCs) produced on Pyrex glass substrates is presented. The PEMFC demonstrators were fabricated with minimized Pt catalyst loadings which were applied by sputter deposition, a standard thin lm deposition process in semiconductor technology. A meander flow field of 1 mm wide channels that are 250 {mu}m deep and spanning 1 x 1 cm{sup 2} was patterned into the glass by wet chemical etching to transport the fuels. A thin film of Cr and Au was deposited on the glass flow fields by sputter deposition to electrically connect the membrane electrode assembly (MEA) that was placed between two such patterned substrates. It was assembled from two Pt loaded porous electrodes and a Na on membrane in a hot-bonding process using Na on solution. The Pt catalyst was applied directly on the porous electrodes of 1.2 x 1.2 cm{sup 2} active area by sputter deposition. To evaluate the feasibility to reduce the amount of the Pt catalyst by applying this technique, demonstrators were prepared with different loadings of Pt to investigate their performance. The characterization of the PEMFCs was performed at room temperature, ambient pressure, and under H{sub 2}/O{sub 2} operation with no external humidification. The peak power density for a fuel cell with a catalyst loading of 0.05 mg cm{sup -2} Pt at anode and cathode is 136 mW cm{sup -2}. With respect to their low Pt loading the performance of the presented microfabricated PEMFCs is remarkable when compared to those of other micro fuel cells published. (orig.)

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

    International Nuclear Information System (INIS)

    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 cm2 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 kWnet 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. (author)

  17. 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)

  18. 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

    sensors showed minimal influence on cell performance, this difference seen in performance is believed to be caused by different bipolar plate materials. The measurement method is suitable for obtaining detailed data for validation of computational models, moreover the results indicate that the method can...... anode and cathode flow plates. The purpose of this study is to investigate the feasibility of the proposed temperature characterization method and to identify the temperature distribution on an operating HT-PEM in various modes of operation, including a 700 h sensors durability test. The embedded...

  19. Effect of prominent gas diffusion layer (GDL) on non-isothermal transport characteristics and cell performance of a proton exchange membrane fuel cell (PEMFC)

    International Nuclear Information System (INIS)

    This paper investigated the effect of prominent gas diffusion layer (GDL) on non-isothermal transport characteristics and cell performance of the proton exchange membrane fuel cell (PEMFC) by the finite-volume SIMPLE-C method coupled with preconditioned conjugate gradient methods. The geometric parameters of prominent GDL are involved in the amount (N = 5, 7, and 9) and the height (HP = 0.21, 0.31, and 0.41 mm) of prominences with the same GDL thickness for investigating the cell performance considering the effect of liquid water formation in the fluid flow field. The results show that compared with flat GDL, the prominent GDL with N = 7 and HP = 0.21 mm prominences enhances the cell net power best by approximately 15.07% among all geometric designs. - Highlights: • We study how amount and height of prominent gas diffusion layer influence PEM cell net power. • Better local PEM cell power and liquid water removal are got around the GDL prominence. • Prominent GDL creates stronger forced convection and enlarged contact area of reactant gas. • Larger height and amount of GDL prominences has a stronger intrusion effect into channel. • Maximum enhancement of cell net power is 15.07% with prominence of 7 amount, 0.21 mm height

  20. 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.

  1. Improve the efficiency of PEMFC using neutron imaging

    International Nuclear Information System (INIS)

    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 mm2 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 106 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

  2. Swelling behavior of PEMFC during conditioning

    OpenAIRE

    Parrondo, J.; M. Ortueta; F. Mijangos

    2007-01-01

    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 ...

  3. Current Distribution Mapping for PEMFCs

    International Nuclear Information System (INIS)

    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

  4. Nonlinear Modeling and Neuro-Fuzzy Control of PEMFC

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    The proton exchange membrane generation technology is highly efficient, and clean and is considered as the most hopeful "green" power technology. The operating principles of proton exchange membrane fuel cell (PEMFC) system involve thermodynamics, electrochemistry, hydrodynamics and mass transfer theory, which comprise a complex nonlinear system, for which it is difficult to establish a mathematical model and control online.This paper analyzed the characters of the PEMFC; and used the approach and self-study ability of artificial neural networks to build the model of nonlinear system, and adopted the adaptive neural-networks fuzzy infer system to build the temperature model of PEMFC which is used as the reference model of the control system, and adjusted the model parameters to control online. The model and control were implemented in SIMULINK environment.The results of simulation show the test data and model have a good agreement. The model is useful for the optimal and real time control of PEMFC system.

  5. 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)

    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 CH4 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 CO2 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

  6. Heat transfer management in PEMFC

    International Nuclear Information System (INIS)

    Full text: Proton exchange membrane fuel cell (PEMFC) is a very promising type of fuel cell regarding energy efficiency, power density and specific power, though it is still facing major technical challenges to the commercialization, including water management, thermal management, R and D of new materials with lower cost and better performance, etc. Thermal management is a challenging issue due to the facts that PEM fuel cells must be operated in a narrow suitable temperature range, that it is difficult to remove the generated heat which is no less than the electric energy produced while the heat generation is usually non-uniform. It is critical to clearly understand the mechanism of heat and mass transfer issues in PEM fuel cells to realize better thermal management, including heat generation, heat transfer mechanism, temperature distribution, mass distribution, etc. Numerical modeling is a very useful tool in studying mechanism of heat generation, heat and mass transfer as well as other issues in PEM fuel cells but, the models should be validated with experimental measurements. In this respect, in-situ diagnosis is a crucial approach to the understanding of such issues and validation of modeling study. (authors)

  7. 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)

  8. Chelating agent assisted heat treatment of carbon supported cobalt oxide nanoparticle for use as cathode catalyst of polymer electrolyte membrane fuel cell (PEMFC)

    International Nuclear Information System (INIS)

    Cobalt-based catalysts for the oxygen reduction reaction (ORR) in polymer electrolyte membrane fuel cell (PEMFC) have been successfully incorporated cobalt oxide (Co3O4) onto Vulcan XC-72 carbon powder by thermal decomposition of Co-ethylenediamine complex (ethylenediamine, NH2CH2CH2NH2, denoted en) at 850 oC. The catalysts were prepared by adsorbing the cobalt complexes [Co(en)(H2O)4]3+, [Co(en)2(H2O)2]3+ and [Co(en)3]3+ on commercial XC-72 carbon black supports, loading amount of Co with respect to carbon black was about 2%, the resulting materials have been pyrolyzed under nitrogen atmosphere to create CoOx/C catalysts, donated as E1, E2, and E3, respectively. The composite materials were characterized using X-ray diffraction (XRD), high-resolution transmission electron microscopy (HRTEM) and X-ray photoelectron spectroscopy (XPS). Chemical compositions of prepared catalysts were determined using inductively-coupled plasma-atomic emission spectroscopy (ICP-AES). The catalytic activities for ORR have been analyzed by cyclic voltammetry (CV) and linear sweep voltammetry (LSV). The electrocatalytic activity for oxygen reduction of E2 is superior to that of E1 and E3. Membrane electrode assemblies (MEAs) containing the synthesized CoOx/C cathode catalysts were fabricated and evaluated by single cell tests. The E2 cathode performed better than that of E1 and E3 cathode. This can be attributed to the enhanced activity for ORR, in agreement with the composition of the catalyst that CoO co-existed with Co3O4. The maximum power density 73 mW cm-2 was obtained at 0.3 V with a current density of 240 mA cm-2 for E2 and the normalized power density of E2 is larger than that that of commercial 20 wt.% Pt/C-ETEK. -- Highlights: → Non-noble catalysts have been attracting increasing attention due to become a low-cost alternative catalyst for oxygen reduction in PEMFC. → This method for the production of nanoparticle cobalt oxides which can be incorporated into Vulcan XC-72

  9. Evaluation of reciprocating electromagnetic air pumping for portable PEMFC

    International Nuclear Information System (INIS)

    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)

  10. Nonlinear modeling of PEMFC based on neural networks identification

    Institute of Scientific and Technical Information of China (English)

    SUN Tao; CAO Guang-yi; ZHU Xin-jian

    2005-01-01

    The proton exchange membrane generation technology is highly efficient and clean, and is considered as the most hopeful "green" power technology. The operating principles of proton exchange membrane fuel cell (PEMFC) system involve thermodynamics, electrochemistry, hydrodynamics and mass transfer theory, which comprise a complex nonlinear system, for which it is difficult to establish a mathematical model. This paper first simply analyzes the necessity of the PEMFC generation technology, then introduces the generating principle from four aspects: electrode, single cell, stack, system; and then uses the approach and self-study ability of artificial neural network to build the model of nonlinear system, and adapts the Levenberg-Marquardt BP (LMBP) to build the electric characteristic model of PEMFC. The model uses experimental data as training specimens, on the condition the system is provided enough hydrogen. Considering the flow velocity of air (or oxygen) and the cell operational temperature as inputs, the cell voltage and current density as the outputs and establishing the electric characteristic model of PEMFC according to the different cell temperatures. The voltage-current output curves of model has some guidance effect for improving the cell performance, and provide basic data for optimizing cell performance that have practical significance.

  11. Bionic Concept Applied to Flow Slab Design of PEMFC

    Science.gov (United States)

    Wang, C. T.; Chang, C. P.

    A character of fuel cell with high potency and low pollution was known well and considered as a new generation of power technology. In this study a novel design of flow slab addressed and originated from bionic concept will be applied to improve the performance of PEMFC. Simulation results executed at Re = 100 show that the bionic flow type will possess a better uniformity of velocity and lower pressure drop. Besides, the integral performance concerned at SDR and PDR will also show the bionic flow type to be an outstanding design. Hence, this novel flow design addressed will be useful to promotion of PEMFC.

  12. Nonlinear Predictive Control for PEMFC Stack Operation Temperature

    Institute of Scientific and Technical Information of China (English)

    LI Xi; CAO Guang-yi; ZHU Xin-jian

    2005-01-01

    Operating temperature of proton exchange membrane fuel cell stack should be controlled within a special range. The input-output data and operating experiences were used to establish a PEMFC stack model and operating temperature control system. A nonlinear predictive control algorithm based on fuzzy model was presented for a family of complex system with severe nonlinearity such as PEMFC. Based on the obtained fuzzy model, a discrete optimization of the control action was carried out according to the principle of Branch and Bound method. The test results demonstrate the effectiveness and advantage of this approach.

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

    International Nuclear Information System (INIS)

    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.

  14. Hybrid intelligent PID control design for PEMFC anode system

    Institute of Scientific and Technical Information of China (English)

    Rui-min WANG; Ying-ying ZHANG; Guang-yi CAO

    2008-01-01

    Control design is important for proton exchange membrane fuel cell (PEMFC) generator. This work researched the anode system of a 60-kW PEMFC generator. Both anode pressure and humidity must he maintained at ideal levels during steady operation. In view of characteristics and requirements of the system, a hybrid intelligent PID controller is designed specifically based on dynamic simulation. A single neuron PI controller is used for anode humidity by adjusting the water injection to the hydrogen cell. Another incremental PID controller, based on the diagonal recurrent neural network (DRNN) dynamic identification, is used to control anode pressure to be more stable and exact by adjusting the hydrogen flow rate. This control strategy can avoid the coupling problem of the PEMFC and achieve a more adaptive ability. Simulation results showed that the control strategy can maintain both anode humidity and pressure at ideal levels regardless of variable load, nonlinear dynamic and coupling characteristics of the system. This work will give some guides for further control design and applications of the total PEMFC generator.

  15. 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

    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...... BOP (balance-of-plant) components, is modeled and coupled to the fuel cell stack subsystem. The micro-CHP system is simulated in LabVIEW environment to provide the ability of Data Acquisition of actual components and thereby more realistic design in the future. A part-load study has been conducted to...

  16. 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)

  17. 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...

  18. 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...

  19. 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.

  20. 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)

  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

    International Nuclear Information System (INIS)

    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 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 BOP (balance-of-plant) components, is modeled and coupled to the fuel cell stack subsystem. The micro-CHP system is simulated in LabVIEWTM environment to provide the ability of Data Acquisition of actual components and thereby more realistic design in the future. A part-load study has been conducted to indicate performance characteristics at off-design conditions. The system is sized to provide realistic dimensioning of the actual system. -- Research highlights: → An HT-PEMFC-based micro-CHP system is modeled in LabVIEW to provide a basis for future experimental calculations. → We examine operation in various loads to indicate performance characteristics at off-design conditions. → An electrical efficiency varying from 45.4% (25%-load) to 38.8% (full-load) was calculated. The corresponding total efficiency was around 95.2%.

  2. An investigation of coated aluminium bipolar plates for PEMFC

    International Nuclear Information System (INIS)

    Highlights: ► Coated aluminium bipolar plates demonstrate the hydrophobic property than the raw material. ► The corrosion behaviour of bipolar plate decreases the PEMFC performance severely. ► These PEMFCs are measured by current–voltage (I–V) curve test. ► The oxide film increases the interfacial contact resistance. -- Abstract: The performance of Al-alloy bipolar plates for the PEMFC (proton exchange membrane fuel cell) system is investigated in this paper. The metallic bipolar plates are modified with a Ni–P coating. The performance of the Al-alloy bipolar plates is evaluated by the coating structure, corrosion resistance, contact angle and single cell performance. The results indicate that the coated aluminium bipolar plates demonstrate hydrophobic and anti-corrosive properties. The hydrophobic property increases the contact angle on the surface from 46.08° to 80.51°. Meanwhile, the corrosion rate of the Ni–P coating can be over 1 order of magnitude lower than that of the substrate. Hence, the substrate with the coating maintains superior performance under the long term test. The present study proves that both the hydrophobicity and corrosion resistance significantly affect the metallic bipolar plate.

  3. Plain carbon steel bipolar plates for PEMFC

    Institute of Scientific and Technical Information of China (English)

    WANG Jianli; SUN Juncai; TIAN Rujin; XU Jing

    2006-01-01

    Bipolar plates are a multifunctional component of PEMFC. Comparing with the machined graphite and stainless steels, the plain carbon steel is a very cheap commercial metal material. In this paper, the possibility of applying the plain carbon steels in the bipolar plate for PEMFC was exploited. In order to improve the corrosion resistance of the low carbon steel in the PEMFCs' environments,two surface modification processes was developed and then the electrochemical performances and interfacial contact resistance (ICR) of the surface modified plate of plain carbon steel were investigated. The results show that the surface modified steel plates have good corrosion resistance and relatively low contact resistance, and it may be a candidate material as bipolar plate of PEMFC.

  4. 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

  5. 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.

  6. Interaction of droplet and sidewalls with modified surfaces in a PEMFC gas flow channel

    Science.gov (United States)

    Shah, Mihir M.

    A Proton Exchange Membrane Fuel Cell (PEMFC) is a clean and highly efficient way of power generation used primarily for transportation applications. Hydrogen and air are supplied to the fuel cell through gas channels, which also remove liquid water generated in the fuel cell. The clogged channels prevent reactant transport to the electrochemically active sites which comprise one of the channel walls and thus, degrading the performance of the cell. Proper management of the product water is a current topic of research interest in commercialization of fuel cell vehicles. Liquid water, produced as by-product of the fuel cell reaction, can clog the gas channels easily since surface tension of water is significant at this length scale. In a PEMFC channel cross-section, water is assumed to be produced in the channel at the center along the flow axis. This assumption is primarily valid and extensively used for experimental purposes. However in a real PEMFC, the water entry is not constrained at the channel center. Hence, more investigations are made using water entry at channel corner (land region) which resulted in contradicting prior results for the water feature behavior for all relevant PEMFC operating conditions, leading to adverse two-phase flow behavior- including slug blockage and fluctuations at channel end. Very limited research is available to study the effect of gas channel surface modifications on the two-phase flow behavior and local PEMFC performance. In this study, the droplet--sidewall dynamic interactions and two--phase local pressure drop across the water droplet present in a PEMFC channel with trapezoidal geometries with surface modifications are studied. These surface modifications include micro-grooves that possess a hybrid wetting regime that will initiate and guide the water feature at channel ends to eject with general ease. Slugs are reduced to films after ejection and thus channel blockage is avoided overcoming the problems caused by water influx

  7. 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.

  8. 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)

  9. Rapid Prototyping Bipolar Plate of PEMFC by Gelcasting

    Institute of Scientific and Technical Information of China (English)

    LUO Bing; CHEN Shang-wei; HUANG Ming-yu; WANG Lian-jun

    2006-01-01

    Bipolar plate is one key component of proton exchange membrane fuel cell (PEMFC). According to this paper, mesocarbon microbeads were used as raw materials for forming the green bodies of bipolar plates with complex flow channels by gelcasting technique. Then, the final bipolar plates would be gained after the green parts were died, burned out and sintered. Meanwhile, its properties are researched and evaluated by the test of flexible strength and electric resistivity. The resultant flexural strength of sintered sample is 67 Mpa and the electric resistivity is 52 μΩ·m.

  10. Research on a simulated 60 kW PEMFC cogeneration system for domestic application

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    The electrical and thermal performances of a simulated 60 kW Proton Exchange Membrane Fuel Cell (PEMFC) cogeneration system are first analyzed and then strategies to make the system operation stable and efficient are developed. The system configuration is described first, and then the power response and coordination strategy are presented on the basis of the electricity model. Two different thermal models are used to estimate the thermal performance of this cogeneration system, and heat management is discussed. Based on these system designs, the 60 kW PEMFC cogeneration system is analyzed in detail. The analysis results will be useful for further study and development of the system.

  11. 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; Jensen, Jens Oluf; Bjerrum, Niels

    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 as...

  12. Validation of a HT-PEMFC stack for CHP applications

    Energy Technology Data Exchange (ETDEWEB)

    Pasupathi, S.; Ulleberg, Oe. [Western Cape Univ. (South Africa). HySA Systems, SAIAMC; Bujlo, P. [Western Cape Univ. (South Africa). HySA Systems, SAIAMC; Electrotechnical Institute Wroclaw Division (Poland); Scholta, J. [Centre for Solar Energy and Hydrogen Research (ZSW) (Germany)

    2010-07-01

    Fuel cell systems are very attractive for stationary co-generation applications as they can produce heat and electricity efficiently in a decentralized and environmentally friendly manner. PEMFC stacks operating at temperatures above 120 C, specifically in the range of 140-180 C, are ideal for co-generation purposes. In this study, preliminary results from a HTPEMFC stack designed for CHP applications is presented and discussed. A short, five-cell, HT-PEMFC stack was assembled with Celtec- P-2100 MEAs and validated in terms of electrical performance. The stack was operated with hydrogen and air at 160 C and the utilization curves for anode and cathode were recorded for a wide range of gas utilization at a current density of 0.52 A/cm{sup 2}. The current voltage characteristic was measured at optimal utilization values at 160 C. A 1kW stack is assembled and is currently being validated for its performance under various operating conditions for use in CHP applications. (orig.)

  13. Effect of cathode separator structure on performance characteristics of free-breathing PEMFCs

    OpenAIRE

    Tabe, Yutaka; Park, Sang-Kyun; Kikuta, Kazushige; Chikahisa, Takemi; Hishinuma, Yukio

    2006-01-01

    The performance of free-breathing polymer electrolyte membrane fuel cells (PEMFCs) was studied experimentally and the effect of the cathode separator structure on the cell performance was investigated. Two types of cathode separators were used for a cell with an 18 cm2 active area: an open type with parallel rectangular open-slits and a channel type with straight vertical channels with open ends. The polarization curves, cell impedance, and contact pressure distribution of the separators were...

  14. Development of the anode bipolar plate/membrane assembly unit for air breathing PEMFC stack using silicone adhesive bonding

    Science.gov (United States)

    Kim, Minkook; Lee, Dai Gil

    2016-05-01

    Polymer electrolyte membrane fuel cells (PEMFC) exhibit a wide power range, low operating temperature, high energy density and long life time. These advantages favor PEMFC for applications such as vehicle power sources, portable power, and backup power applications. With the push towards the commercialization of PEMFC, especially for portable power applications, the overall balance of plants (BOPs) of the systems should be minimized. To reduce the mass and complexity of the systems, air-breathing PEMFC stack design with open cathode channel configuration is being developed. However, the open cathode channel configuration incurs hydrogen leakage problem. In this study, the bonding strength of a silicon adhesive between the Nafion membrane and the carbon fiber/epoxy composite bipolar plate was measured. Then, an anode bipolar plate/membrane assembly unit which was bonded with the silicone adhesive was developed to solve the hydrogen leakage problem. The reliability of the anode bipolar plate/membrane assembly unit was estimated under the internal pressure of hydrogen by the FE analysis. Additionally, the gas sealability of the developed air breathing PEMFC unit cell was experimentally measured. Finally, unit cell performance of the developed anode bipolar plate/membrane assembly unit was tested and verified under operating conditions without humidity and temperature control.

  15. 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.

  16. Theoretical analysis of a biogas-fed PEMFC system with different hydrogen purifications: Conventional and membrane-based water gas shift processes

    International Nuclear Information System (INIS)

    Highlights: • Thermodynamic analysis of the biogas-fed PEMFC system is performed. • Conventional and membrane-based WGS processes for H2 purification are studied. • A flowsheet model of the PEMFC system is developed. • Effect of key parameters on yields of H2 and carbon in the biogas reformer is shown. • Performance of PEMFC systems with different H2 purification processes is analyzed. - Abstract: This study presents a thermodynamic analysis of biogas reforming and proton electrolyte membrane fuel cell (PEMFC) integrated process with different hydrogen purifications: conventional and membrane-based water gas shift processes. The aim is to determine the optimal reforming process for hydrogen production from biogas in the PEMFC system. The formation of carbon is concerned in the hydrogen production. The simulation results show that increases in the steam-to-methane ratio and reformer temperature can improve the hydrogen yield and reduce the carbon formation. From the performance analysis, it is found that when the PEMFC is operated at high temperature and fuel utilization, the overall system efficiency enhances. The performance of the PEMFC system with the installation of a water gas shift membrane unit in the hydrogen purification step is slightly increased, compared with a conventional process

  17. Experimental approaches for distribution and behavior of water in PEMFC under flow direction and differential pressure using neutron imaging technique

    International Nuclear Information System (INIS)

    In this investigation, we prepared a 3-parallel serpentine single PEMFC which has an active area of 25 cm2 and a flow channel cross section of 1x1 mm. Distribution and transport of water in an operating PEMFC were observed by varying the flow directions (co-current and counter-current) in each channel and the differential pressures (100, 200, 300 kPa) applied between the anode and cathode channels. This investigation was performed at the neutron imaging facility at the NIST of which the collimation ratio and neutron fluence rate are 600, 7.2x106 n/s/cm2, respectively. Neutron image was continuously recorded by an amorphous silicon flat panel detector every 1 s during the operation of the fuel cell. It has been observed that the differential pressure affects the total amount of water produced while the flow direction affects the spatial distribution of water when the neutron images were analyzed for several different operating conditions. More specifically, the amount of water production in the fuel cell increased as the partial pressure increases at a given current density and the water production was more uniform for the counter current than the co-current case. It is shown that the neutron imaging technique is a powerful tool to visualize the PEMFC. The information on the water distribution and behavior at an operating PEMFC helps improve the efficiency of PEMFC.

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

    International Nuclear Information System (INIS)

    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.

  19. Technology leadership: a road map to commercially viable PEMFC stack technology. Paper no. IGEC-1-008

    International Nuclear Information System (INIS)

    'Full text:' In February 2005, Ballard announced its most recent advances in PEMFC stack technology. This technology development exhibited, we believe, for the first time the capability of a single PEMFC stack design to demonstrate combined excellence in cost reduction, freeze start capability from -20 C and durability under an automotive OEM defined dynamic operating cycle, comparable to that experienced by a fuel cell stack in an actual vehicle. One month later, building on the above technology leadership demonstration, Ballard announced a technology 'oad map' that defined a path to commercially viability for a PEMFC stack by 2010. The key target parameters for cost reduction, durability, freeze start and stack power density are described in detail along with demonstrated historical capability and a clear path as to how Ballard will achieve the required targets. (author)

  20. Proton exchange membrane fuel cells modeling based on artificial neural networks

    Institute of Scientific and Technical Information of China (English)

    Yudong Tian; Xinjian Zhu; Guangyi Cao

    2005-01-01

    To understand the complexity of the mathematical models of a proton exchange membrane fuel cell (PEMFC) and their shortage of practical PEMFC control, the PEMFC complex mechanism and the existing PEMFC models are analyzed, and artificial neural networks based PEMFC modeling is advanced. The structure, algorithm, training and simulation of PEMFC modeling based on improved BP networks are given out in detail. The computer simulation and conducted experiment verify that this model is fast and accurate, and can be used as a suitable operational model for PEMFC real-time control.

  1. Effect of the relative position of oxygen-hydrogen plate channels and inlets on a PEMFC

    Energy Technology Data Exchange (ETDEWEB)

    Valino, Luis; Mustata, Radu; Gil, Maria Isabel; Martin, Jesus [LITEC, CSIC - Univ. Zaragoza -DGA, Maria de Luna 10, 50018 Zaragoza (Spain)

    2010-10-15

    A numerical study of a PEMFC (proton exchange membrane fuel cell) bipolar plate has been made to study the influence of the relative entry positions of hydrogen and oxygen on the distribution of gases. Various 3D configurations, under simplified working conditions, have been considered. As the main result, it is shown that the flow of the gas in stoichiometric defect (usually hydrogen) forces the pattern of the other reactant gas (oxygen). (author)

  2. Factors influencing electrochemical properties and performance of hydrocarbon based ionomer PEMFC catalyst layers

    OpenAIRE

    Astill, Toby Duncan

    2008-01-01

    This work investigated the properties of catalyst layers for proton exchange membrane fuel cells (PEMFC) that contained sulfonated poly(ether ether ketone) (SPEEK). A series of SPEEK polymers were prepared with varying ion exchange capacity (IEC) to test their oxygen mass transport properties, electrochemical kinetic parameters, proton conductivity, and water sorption characteristics. A simple method to fabricate catalyst layers containing SPEEK and polytetrafluoroethylene (PTFE) was develope...

  3. 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)

  4. 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...

  5. 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 is...

  6. Experimental and computational analysis of a 1.2 kW PEMFC designed for communications backup power applications

    International Nuclear Information System (INIS)

    Usage of Fuel Cells due to their high power density and low greenhouse gas emissions which combine H/sub 2/ and O/sub 2/ electrochemically to produce electricity and H/sub 2/O as the by-product will become widespread in the near future due to its quality, reliability and portability. Among all types of fuel cells, Proton Exchange Membrane Fuel Cells (PEMFC) is most attractive for residential and automotive industry use due to its low operating temperature, silent operation, quick start-up characteristics and better performance. The T-1000 1.2 kW PEMFC are mainly used for communications backup power applications because of its high reliability, simplicity and ease of maintenance in telecommunication sector, utility and government etc. This paper discuses the features of T- 1000 PEMFC and also the production losses due to power outages in US and different parts of the globe and the advantages of using it in different sectors to reduce the production loses occurred by the power outages. This work focuses on the experimental data and the computational data of load, P, V, A and H/sub 2/ consumed under laboratory conditions at Power Lab in Victoria University, Melbourne. The paper also describes various load, P, V and A curves recorded at regular intervals between the experimental and computational data. The work shows notably the benefit of using T-1000 1.2 kW PEMFC for residential, automobile, government and telecom sectors. (author)

  7. The effects of air stoichiometry and air excess ratio on the transient response of a PEMFC under load change conditions

    International Nuclear Information System (INIS)

    Highlights: • Effects of controlling parameters on the transient response of a PEMFC are studied. • The transient response is measured by varying air stoichiometry and air excess ratio. • Voltage drop, undershoot, and voltage fluctuation are analyzed under the load change. • Optimal air stoichiometry and air excess ratio are suggested for stable operation. - Abstract: The transient response of a proton exchange membrane fuel cell (PEMFC) is an important issue for transportation applications. The objective of this study is to investigate the effects of operating and controlling parameters on the transient response of a PEMFC for achieving more stable cell performance under load change conditions. The transient response of a PEMFC was measured and analyzed by varying air stoichiometry, air humidity, and air excess ratio (AER). The optimal air stoichiometry and AER were determined to minimize the voltage drop, undershoot, and voltage fluctuation under the load change, while maintaining high cell performance. Based on the present data, the optimal air stoichiometry was determined to be between 2.0 and 2.5, and the optimal AER was suggested to be between 1.65 and 2.0

  8. Modelling study of CO 2 poisoning on PEMFC anodes

    Science.gov (United States)

    Janssen, G. J. M.

    The CO 2 poisoning effect on anodes for the proton-exchange-membrane fuel cell (PEMFC) was examined by model studies. It was assumed that the reverse water gas shift reaction (RWGS) is the origin of the CO 2 poisoning effects. The relation between the anode polarisation losses and the catalytic properties of the catalyst was investigated with a kinetic model and with a fuel cell model including finite utilisation of the fuel. It was found that the main effect of the occurrence of the reverse water gas shift reaction is that a large part of the catalytic surface area becomes inactive for hydrogen dissociation. Desorption of CO formed by reduction of CO 2 followed by transport down the anode gas channel and subsequent re-adsorption on the catalyst was shown to play a minor role. In reformate gas, where besides CO 2 traces of CO are present, CO 2 poisoning will have the largest effect when the CO content is small and at relatively low current density.

  9. Evaluation of water transport in PEMFC gas diffusion layers using image analysis

    Science.gov (United States)

    Daino, Michael Mario

    Liquid water transport through the gas diffusion layer (GDL) of a proton exchange membrane fuel cell (PEMFC) was investigated through three interrelated studies utilizing the tools of image processing. First, a new framework and model for the digital generation and characterization of the microstructure of GDL materials with localized binder and polytetrafluoroethylene (PTFE) distributions were developed using 3D morphological imaging processing. The new generation technique closely mimics manufacturing processes and produces realistic 3D phase-differentiated digital microstructures in a cost- and time- effective manner. The generated distributions of hydrophobic (PTFE) and hydrophilic (carbon) regions representative of commercial GDL materials provides water transport modeling efforts with more accurate geometries to improve PEMFC water management. Second, through-plane transport in an operating PEMFC was investigated by developing and testing a transparent (visible and infrared) fuel cell. Visible observations and subsequent video processing revealed condensation of microdroplets on the GDL and implied the existence of condensation within the GDL. Temperature gradients across the cathode GDL under realistic operating conditions were obtained in a noninvasive manner using infrared imaging and subsequent image analysis. Recommendations for improving accuracy of PEMFC temperature measurements using infrared imaging were made. The final contribution of this work was the measurement and analysis of water breakthrough dynamics across GDL materials with and without microporous layers (MPLs). Dynamic breakthrough events, or recurrent breakthroughs, were observed for all GDL material investigated indicating the breakdown and re-build of water paths through the GDL caused by an intermittent water drainage process from the GDL surface. GDL materials without an MPL exhibited a dynamic breakthrough location phenomenon and significantly elevated water saturations. The results

  10. 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)

  11. 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.

  12. Formulation of an electric equivalent circuit of PEMFC and its behavioral studies under steady and transient conditions

    International Nuclear Information System (INIS)

    In this paper electric equivalence model is formulated is formulated for the constructional and operational features of a Polymer Electrolyte Membrane Fuel Cell (PEMFC). The proposed model is capable of explaining the behavior of PEMFC in both steady state and transient modes of operation. For the efficient designing of fuel cell related applications it is highly desirable to model the electrical output of fuel cell in terms of its internal electrochemical dynamics. The proposed model includes the phenomenon like activation polarization, ohmic polarization and mass transport effect. An analogical electrical circuit is formulated by taking these phenomena into considerations. Within acceptable limits, the effects of load variation on output voltage, efficiency and fuel flow demands are also investigated. The static and dynamic characteristics obtained through simulations are compared with the standard available data. Simulation results show that the model can be used in PEM fuel cell distributed generation related control studies. (author)

  13. A study of water transport as a function of the micro-porous layer arrangement in PEMFCs

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Taeyoung; Lee, Seungjae; Park, Heekyung [Department of Civil and Environmental Engineering, KAIST, Guseong-dong, Yuseong-gu, Daejeon, 305-701 (Korea)

    2010-08-15

    Electrochemical losses as a function of the micro-porous layer (MPL) arrangement in Proton Exchange Membrane Fuel Cells (PEMFCs) are investigated by electrochemical impedance spectroscopy (EIS). Net water flux across the polymer membrane in PEMFCs is investigated for various arrangements of the MPL, namely with MPL on the cathode side alone, with MPL on both the cathode and the anode sides and without MPL. EIS and water transport are recorded for various operating conditions, such as the relative humidity of the hydrogen inlet and current density, in a PEMFC fed by fully-saturated air. The cell with an MPL on the cathode side alone has better performance than two other types of cells. Furthermore, the cell with an MPL on only the cathode increases the water flux from cathode to anode as compared to the cells with MPLs on both electrodes and cells without MPL. Oxygen-mass-transport resistances of cells in the presence of an MPL on the cathode are lower than the values for the other two cells, which indicates that the molar concentration of oxygen at the reaction surface of the catalyst layer is higher. This suggests that the MPL forces the liquid water from the cathode side to the anode side and decreases the liquid saturation in GDL at high current densities. Consequently, the MPL helps in maintaining the water content in the polymer membrane and decreases the cathode charge transfer and oxygen-mass transport resistances in PEMFCs, even when the hydrogen inlet has a low relative humidity. (author)

  14. In situ and ex situ characterization of carbon corrosion in PEMFCs

    Energy Technology Data Exchange (ETDEWEB)

    Fairweather, Joseph D [Los Alamos National Laboratory; Bo, Li [Los Alamos National Laboratory; Mukundan, Rangachary [Los Alamos National Laboratory; Borup, Rodney L [Los Alamos National Laboratory; Fenton, James [FLORIDA SOLAR ENERGY CENTER

    2010-01-01

    Carbon corrosion is an important degradation mechanism that impairs PEMFC performance through destruction of catalyst connectivity, collapse of pore structure, and loss of hydrophobic character. In this study, carbon corrosion was quantified in situ by measurement of carbon dioxide in fuel cell exhaust gases through non-dispersive infrared spectroscopy (NDIR). Performance degradation was also studied by a DOE protocol for catalyst support accelerated stress testing. Finally, changes in gas diffusion layer and microporous layer carbon surfaces were observed through an ex situ aging procedure.

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

    OpenAIRE

    Jingming Liang; Zefeng Wu

    2015-01-01

    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...

  16. Development of highly active and stable hybrid cathode catalyst for PEMFCs

    Science.gov (United States)

    Jung, Won Suk

    Polymer electrolyte membrane fuel cells (PEMFCs) are attractive power sources of the future for a variety of applications including portable electronics, stationary power, and automobile application. However, sluggish cathode kinetics, high Pt cost, and durability issues inhibit the commercialization of PEMFCs. To overcome these drawbacks, research has been focused on alloying Pt with transition metals since alloy catalysts show significantly improved catalytic properties like high activity, selectivity, and durability. However, Pt-alloy catalysts synthesized using the conventional impregnation method exhibit uneven particle size and poor particle distribution resulting in poor performance and/or durability in PEMFCs. In this dissertation, a novel catalyst synthesis methodology is developed and compared with catalysts prepared using impregnation method and commercial catalysts. Two approaches are investigated for the catalyst development. The catalyst durability was studied under U. S. DRIVE Fuel Cell Tech Team suggested protocols. In the first approach, the carbon composite catalyst (CCC) having active sites for oxygen reduction reaction (ORR) is employed as a support for the synthesis of Pt/CCC catalyst. The structural and electrochemical properties of Pt/CCC catalyst are investigated using high-resolution transmission electron microscopy, X-ray diffraction, and X-ray photoelectron spectroscopy, while RDE and fuel cell testing are carried out to study the electrochemical properties. The synergistic effect of CCC and Pt is confirmed by the observed high activity towards ORR for the Pt/CCC catalyst. The second approach is the synthesis of Co-doped hybrid cathode catalysts (Co-doped Pt/CCC) by diffusing the Co metal present within the CCC support into the Pt nanoparticles during heat-treatment. The optimized Co-doped Pt/CCC catalyst performed better than the commercial catalysts and the catalyst prepared using the impregnation method in PEMFCs and showed high

  17. Conceito de Desenvolvimento

    OpenAIRE

    Vale, MC

    2005-01-01

    A autora aborda os diferentes modelos de desenvolvimento humano que ao longo da história têm explicado o desenvolvimento de forma sucessivamente mais aperfeiçoada, transportando conceitos inovadores de grande aplicabilidade em pediatria e repercussão nas estratégias educativas.

  18. Simulation of the catalyst layer in PEMFC based on a novel two-phase lattice model

    International Nuclear Information System (INIS)

    Highlights: → We propose a novel two phase lattice model of catalyst layer in PEMFC. → The model features a catalyst phase and a mixed ionomer and pores phase. → Transport and electrochemical reaction in the lattice are simulated. → The model enables more accurate results than pore-solid two phase model. → Profiles of oxygen level and reaction rate across catalyst layer vary with cell current. - Abstract: A lattice model of catalyst layer in proton exchange membrane fuel cells (PEMFCs), consisting of randomly distributed catalyst phase (C phase) and mixed ionomer-pore phase (IP phase), was established by means of Monte Carlo method. Transport and electrochemical reactions in the model catalyst layer were calculated. The newly proposed C-IP model was compared with previously established pore-solid two phase model. The variation of oxygen level and reaction rate along the thickness of catalyst layer with cell current was discussed. The effect of ionomer distribution across catalyst layer was studied by comparing profiles of oxygen level, reaction rate and overpotential, as well as corresponding polarization curves.

  19. 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%.

  20. Quantification of the hydrogen produced by Spirulina maxima using a PEMFC

    Energy Technology Data Exchange (ETDEWEB)

    Juantorena, U.A.; Gamboa, S.A. [Univ. Nacional Autonoma de Mexico, Morelos (Mexico). Centro de Investigacion en Energia; Sebastian, P.J. [Univ. Nacional Autonoma de Mexico, Morelos (Mexico). Centro de Investigacion en Energia]|[Univ. Politecnica de Chiapas (Mexico); Bustos, G.A. [Univ. Nacional Autonoma de Mexico, Morelos (Mexico). Centro de Ciencias Fisicas

    2006-07-01

    This paper addressed the challenges associated with producing hydrogen through biological methods, and the potential for biotechnology to resolve them. It has been shown that cyanobacteria can produce hydrogen through auto-fermentation under anaerobic conditions in the dark. In this study, the amount of hydrogen produced by the photosynthetic micro-algae Spirulina maxima 2342 under different experimental conditions was quantified. The produced hydrogen was then fed into a proton exchange membrane fuel cell (PEMFC) and was quantified from the electricity generated in the fuel cell. The Faraday efficiency was calculated by substituting the current density in the regression equation. The hydrogen flow into the cell was calculated in terms of its relation to the hydrogen produced by the bioreactor. It was shown that higher potential values, hydrogen flow and Faraday efficiency correspond to higher light intensity values. It was concluded that a PEMFC can be used to quantify the hydrogen produced by a photosynthetic micro-algal system. 5 refs., 2 tabs.

  1. 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.

  2. 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

  3. Comparison of high-temperature and low-temperature polymer electrolyte membrane fuel cell systems with glycerol reforming process for stationary applications

    International Nuclear Information System (INIS)

    Highlights: • PEMFC systems with a glycerol steam reformer for stationary application are studied. • Performance of HT-PEMFC and LT-PEMFC systems is compared. • HT-PEMFC system shows good performance over LT-PEMFC system at a high current density. • HT-PEMFC system with water gas shift reactor shows the highest system efficiency. • Heat integration can improve the efficiency of HT-PEMFC system. - Abstract: A high-temperature polymer electrolyte membrane fuel cell (HT-PEMFC) has a major advantage over a low-temperature polymer electrolyte fuel cell (LT-PEMFC) demonstrated by a tolerance to a higher CO content in the hydrogen feed and thus a simpler fuel processing. In this study, a direct comparison between the performance of HT-PEMFC and LT-PEMFC systems integrated with a glycerol steam reformer with and without a water gas shift reactor is shown. Under pure hydrogen operation, the LT-PEMFC performance is superior to the HT-PEMFC. However, the HT-PEMFC system shows good performance over the LT-PEMFC system when operated under high current density and high pressure (3 atm) and using the reformate gas derived from the glycerol processor as fuel. At high current density, the high concentration of CO is the major limitation for the operation of HT-PEMFC system without water gas shift reactor, whereas the LT-PEMFC suffers from CO poisoning and restricted oxygen mass transport. Considering the system efficiency with co-heat and power generation, the HT-PEMFC system with water gas shift reactor shows the highest overall system efficiency (approximately 60%) and therefore one of the most suitable technologies for stationary applications

  4. 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.

  5. Evaluation of the corrosion resistance of Ni-Co-B coatings in simulated PEMFC environment

    International Nuclear Information System (INIS)

    The corrosion resistance behavior of Ni-Co-B coated carbon steel, Al 6061 alloy and 304 stainless steel was evaluated in simulated proton exchange membrane fuel cell (PEMFC) environment. The phase structure of the NiCoB based alloy was determined by Rietveld analysis. The PEMFC environment was constituted of 0.5 M H2SO4 at 60 oC and the evaluation techniques employed included potentiodynamic polarization, linear polarization resistance, open circuit potential measurements and electrochemical impedance spectroscopy. The results showed that in all cases the corrosion resistance of the Ni-Co-B coating was higher than that of the uncoated alloys; about two orders of magnitude with respect to carbon steel and an order of magnitude compared to 304 stainless steel. Except for the uncoated 304 type stainless steel, the polarization curves for the coated specimens did not exhibit a passive region but only anodic dissolution. The corrosion potential value, E corr, was always nobler for the coated samples than for the uncoated specimens. This was true for the stainless steel in the passive region, but in the active state for the carbon steel and Al 6061 alloy. The corrosion of the underlying alloy occurred due to filtering of the solution through coating defects like microcracks, pinholes, etc. During the filtering process the E corr value of the coating decreased slowly until it reached a steady state value, close to the E corr value of the underlying alloy

  6. Three-Dimensional Lattice Boltzmann Simulation of Liquid Water Transport in Porous Layer of PEMFC

    Directory of Open Access Journals (Sweden)

    Bo Han

    2015-12-01

    Full Text Available A three-dimensional two-phase lattice Boltzmann model (LBM is implemented and validated for qualitative study of the fundamental phenomena of liquid water transport in the porous layer of a proton exchange membrane fuel cell (PEMFC. In the present study, the three-dimensional microstructures of a porous layer are numerically reconstructed by a random generation method. The LBM simulations focus on the effects of the porous layer porosity and boundary liquid saturation on liquid water transport in porous materials. Numerical results confirm that liquid water transport is strongly affected by the microstructures in a porous layer, and the transport process prefers the large pores as its main pathway. The preferential transport phenomenon is more profound with a decreased porous layer porosity and/or boundary liquid saturation. In the transport process, the breakup of a liquid water stream can occur under certain conditions, leading to the formation of liquid droplets inside the porous layer. This phenomenon is related to the connecting bridge or neck resistance dictated by the surface tension, and happens more frequently with a smaller porous layer porosity. Results indicate that an optimized design of porous layer porosity and the combination of various pore sizes may improve both the liquid water removal and gaseous reactant transport in the porous layer of a PEMFC.

  7. 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.

  8. Polymer composite membrane incorporated with a hygroscopic material for high-temperature PEMFC

    International Nuclear Information System (INIS)

    A polymer composite membrane incorporated with a hygroscopic material for high-temperature polymer electrolyte membrane fuel cell (PEMFC) was prepared by hot-pressing the mixture of melt fabricable perfluorosulfonylfluroride copolymer resin (Nafion resin) with fine mordenite powder. The composite membranes with various modernite contents were fabricated. The physico-chemical properties of composite membranes, such as tensile strength and proton conductivity were investigated. The proton conductivity in composite membranes increased with increasing mordenite content at high temperature above 90 deg. C due to water in the mordenite. In addition, the results of current-voltage relationship for single cells at various operation temperatures showed that the composite membrane, containing 10 wt.% mordenite has better performance than the others. It suggests that the improvements of fuel cell performance are not due simply to increased water content in the composite membrane, but that there is an interaction between proton mobility and structure

  9. Diagnosis of PEMFC stack failures via electrochemical impedance spectroscopy

    Science.gov (United States)

    Merida-Donis, Walter Roberto

    -failure conditions. Approximate membrane conductivities were calculated using this model. The calculations yielded a range from 0.04 to 0.065 S cm-1 (under normal humidification), and conductivities that deviated from these nominal range under flooding or dehydrating conditions. The highest conductivity value (was ˜0.10 S cm-1) was measured under flooding conditions at j = 0.4 A cm-2. The lowest conductivity (˜0.02 S cm-1) corresponded to a dehydrated cell at j = 0.1 A cm-2. These values fall within the ranges of published data for modern proton exchange membranes. The phenomenological and numerical results reported in this work represent the first demonstration of these techniques on a PEMFC stack under real operating conditions. They are also the basis of ongoing research, development, and intellectual property protection.

  10. PEMFC双极板的材料及制备工艺综述%Materials and preparation of bipolar plates in PEMFC

    Institute of Scientific and Technical Information of China (English)

    林政宇; 张杰; 刘兵; 郑永平

    2012-01-01

    质子交换膜燃料电池(PEFMC)具有高效、环保等优点,是未来重要的新型能源.作为PEMFC的关键组件同时又是制约PEMFC发展的重要因素,价格低廉、性能优良的双极板研究和开发对于PEMFC的发展有着至关重要的作用.综合阐述了目前几类用于制备PEMFC双极板的材料及其制备工艺,对其利弊做出了分析,并讨论了双极板材料的未来发展方向.%Proton exchange membrane fuel cell (PEMFC), with advantages such as high efficiency and environmental protection, is regarded as an important new energy in the future. The research and development of bipolar plate with lower cost and excellent property are very important for PEMFC because bipolar plates are not only one of the key components of PEMFC, but also one of the factors that restrict the development of PEMFC. In this article, both advantages and disadvantages of bipolar plate materials at present were compared and analyzed. The direction of the future bipolar plates development was also discussed.

  11. 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)

  12. Dynamic analysis of PEMFC-based CHP systems for domestic application

    International Nuclear Information System (INIS)

    Highlights: ► Dynamic model of a CHP energy system based on a PEM fuel cell was developed. ► The CHP system behavior at variable electrical and thermal load was investigated. ► The optimal RH value was assessed maximizing PEMFC performance through simulations. ► The system best operating conditions are characterized by a RH value equal to 50%. -- Abstract: Fuel cell-based CHP systems for distributed residential power generation represent an interesting alternative to traditional thermoelectric plants. This is mainly due to the high efficiency obtainable in the production of electricity and heat in a decentralised, quiet and environmental friendly way. The current paper focuses on the development, in Matlab®Simulink environment, of a complete dynamic model of a residential cogenerative (CHP) energy system consisting of the Proton Exchange Membrane fuel cell (PEMFC), fuel processor, heat exchangers, humidifier and auxiliary hot water boiler. The target of the study is the investigation through such a model of the behavior of CHP systems based on fuel cell (FC) at variable electrical and thermal load, in reference to typical load curves of residential users. With the aim to evaluate the system performance (efficiency, fuel consumption, hot water production, response time) and then to characterize its better operating conditions with particular attention to air relative humidity, suitable simulations were carried out. They are characterized by the following of a typical electrical load trend and in relation to two different thermal load profiles. The dynamic model presented in this paper has allowed to observe the fully functioning of the FC based system under variable loads and it has permitted to design appropriate control logics for this system.

  13. Desenvolvimento profissional do professor

    OpenAIRE

    Gaspar, Helena Maria Pereira

    2014-01-01

    O presente trabalho, num primeiro momento, reporta todo um percurso civilizacional ancorado no desenvolvimento do professor. Na sequência deste estudo, foram retratados, numa perspetiva diacrónica, os vários contextos e as correntes educacionais que, em parte, assumem perenidade no pensamento e no agir atual. No entanto, a busca incessante do desenvolvimento da vida social destacou a figura do professor como o principal agente a quem são atribuídos inúmeros e diferentes papéis,...

  14. 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

    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......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......-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...

  15. The design and cost analysis of a portable PEMFC UPS system

    Energy Technology Data Exchange (ETDEWEB)

    Chang, Hsin-Ping; Chou, Chao-Ling; Chen, Yong-Song; Hou, Tien-I; Weng, Biing-Jyh [Chung Shan Institute of Science and Technology (CSIST), Armaments Bureau, M.N.D (China)

    2007-03-15

    This paper describes the development, assembly, and test of a portable PEMFC UPS system (CSIST-50-01). CSIST-50-01 is a fuel cell power generator with a dc/dc converter to supply a clean, stable, and high quality power at 20 Vdc. Under dry H{sub 2}/air operating condition, the peak power output is about 80 W at 20 V, and maximum system efficiency is about 30% at 60 W. CSIST-50-01 could function as an uninterruptible power supply (UPS) to be a power generator to prevent electronic devices from power interruption. Performance evaluation proves that CSIST-50-01 has fast power responses. CSIST-50-01 costs US$2739-2779, which could be reduced by mass production. Finally, the system characteristics and specifications are compared with other similar systems such as PowerPEM {sup registered} PS-250 (PlugPower), and A-500 (Phoenixtec power). (author)

  16. Highly active and stable platinum catalyst supported on porous carbon nanofibers for improved performance of PEMFC

    International Nuclear Information System (INIS)

    Porous carbon nanofibers (PCNFs) were used as the support to prepare platinum (Pt) catalyst (Pt/PCNFs) for proton exchange membrane fuel cell (PEMFC) applications. As a comparison, Pt supported on carbon black (Vulcan XC-72) (Pt/Vulcan) was also synthesized by the same ethylene glycol reduction method. Platinum was more uniformly deposited on PCNFs than that on the Vulcan XC-72. The electrocatalytic activity and stability of the resultant catalysts along with the commercial one (JM20) were investigated using cyclic voltammetry (CV) and linear sweep voltammetry (LSV) with a rotating disk electrode (RDE). The Pt/PCNFs exhibited much-enhanced electrocatalytic activity and stability compared with the Pt/Vulcan and JM20. The mass activity (at 0.80 V) of Pt/PCNFs is 2.6 times higher and 20% higher than that of Pt/Vulcan and JM20, respectively; the Pt/PCNFs retained about 50% of ECSA whereas JM20 and Pt/Vulcan kept only 25% and 5% of ECSA, respectively, even after 1000 cycles. Furthermore, the single cell performance of Pt/PCNFs was superior to that of Pt/Vulcan and even better than JM20 during high current densities. The cross-section of the membrane electrode assembly (MEA) showed that the Pt/PCNFs construct a loose three-dimensionally connected catalyst layer that is totally different from the tightly stacking catalyst layer composed of carbon black support. Thus, the mass transfer resistance is reduced and water drainage becomes easy when Pt/PCNFs were used as cathode catalyst. These results indicate PCNFs a promising candidate as catalyst supports for the enhancement of PEMFC performance

  17. Development of analytical techniques to study H2s poisoning of PEMFCs and components

    Energy Technology Data Exchange (ETDEWEB)

    Brosha, Eric L [Los Alamos National Laboratory; Rockward, Tommy [Los Alamos National Laboratory; Uribe, Francisco A [Los Alamos National Laboratory; Garzon, Fernando H [Los Alamos National Laboratory

    2008-01-01

    Polymer electrolyte membrane fuel cells are sensitive to impurities that may be present in either the oxidizer or fuel. H{sub 2}S, even at the ppb level, will have a dramatic and adverse affect on fuel cell performance. Not only is it important to know a particular material's affinity to adsorb H{sub 2}S, when considering materials for PEMFC applications, issues such as permeation and crossover rates also become extremely important Several experimental methods have been developed to quantify H{sub 2}S adsorption onto surfaces and to quantify H{sub 2}S permeation through Nafion(reg.) membranes using readily available and inexpensive Ag/AgS ion probes. In addition to calculating the H{sub 2}S uptake on commonly used XC-72 carbon supports and PtlXC-72 catalysts, the H{sub 2}S permeability through dry and humidified Nafion(reg.) PEMFC membranes was also studied using these specialized techniques. In each ion probe experiment performed, a sulfide anti-oxidant buffer solution was used to trap and concentrate trace quantities of H{sub 2}S during the course of the measurement. Crossover experiments were conducted for up to 24 hours in order to achieve sulfide ion concentrations high enough to be precisely determined by subsequent titration with Pb(NO{sub 3}){sub 2}. By using these techniques, we have confirmed H{sub 2}S crossover in Nafion(reg.) membranes and have calculated preliminary rates of H{sub 2}S crossover.

  18. 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.

  19. Water Uptake in PEMFC Catalyst Layers

    Energy Technology Data Exchange (ETDEWEB)

    Gunterman, Haluna P.; Kwong, Anthony H.; Gostick, Jeffrey T.; Kusoglu, Ahmet; Weber, Adam Z.

    2011-07-01

    Water uptake profiles of proton-exchange-membrane fuel-cell catalyst layers are characterized in the form of capillary-pressure saturation (Pc-S) curves. The curves indicate that the catalyst layers tested are highly hydrophilic and require capillary pressures as low as -80 kPa to eject imbibed water. Comparison of materials made with and without Pt indicates a difference in water ejection and uptake phenomena due to the presence of Pt. The addition of Pt increases the tendency of the catalyst layer to retain water. Dynamic vapor sorption (DVS) is used to characterize the water-vapor sorption onto Nafion, Pt/C, and C surfaces. The DVS results align with the trends found from the Pc-S curves and show an increased propensity for water uptake in the presence of Pt. The effect of the ion in Nafion, sodium or protonated form, is also compared and demonstrates that although the protonation of the Nafion in the catalyst layer also increases hydrophilicity, the effect is not as great as that caused by Pt.

  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...... shift (WGS) reactor, heat exchangers, and other balance-of-plant (BOP) components. The objective function of the single-objective optimization strategy is the net electrical efficiency of the micro-CHP system. The implemented optimization procedure attempts to maximize the objective function by...

  1. Design of an integrated fuel processor for residential PEMFCs applications

    Science.gov (United States)

    Seo, Yu Taek; Seo, Dong Joo; Jeong, Jin Hyeok; Yoon, Wang Lai

    KIER has been developing a novel fuel processing system to provide hydrogen rich gas to residential PEMFCs system. For the effective design of a compact hydrogen production system, each unit process for steam reforming and water gas shift, has a steam generator and internal heat exchangers which are thermally and physically integrated into a single packaged hardware system. The newly designed fuel processor (prototype II) showed a thermal efficiency of 78% as a HHV basis with methane conversion of 89%. The preferential oxidation unit with two staged cascade reactors, reduces, the CO concentration to below 10 ppm without complicated temperature control hardware, which is the prerequisite CO limit for the PEMFC stack. After we achieve the initial performance of the fuel processor, partial load operation was carried out to test the performance and reliability of the fuel processor at various loads. The stability of the fuel processor was also demonstrated for three successive days with a stable composition of product gas and thermal efficiency. The CO concentration remained below 10 ppm during the test period and confirmed the stable performance of the two-stage PrOx reactors.

  2. MEIO AMBIENTE E DESENVOLVIMENTO

    OpenAIRE

    Suely Salgueiro Chacon; Daniel Rodriguez de Carvalho Pinheiro; Francisco Correia de Oliveira; Elizabeth Castelo Branco de Souza

    2009-01-01

    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 d...

  3. An artificial neural network ensemble method for fault diagnosis of proton exchange membrane fuel cell system

    International Nuclear Information System (INIS)

    The commercial viability of PEMFC (proton exchange membrane fuel cell) systems depends on using effective fault diagnosis technologies in PEMFC systems. However, many researchers have experimentally studied PEMFC (proton exchange membrane fuel cell) systems without considering certain fault conditions. In this paper, an ANN (artificial neural network) ensemble method is presented that improves the stability and reliability of the PEMFC systems. In the first part, a transient model giving it flexibility in application to some exceptional conditions is built. The PEMFC dynamic model is built and simulated using MATLAB. In the second, using this model and experiments, the mechanisms of four different faults in PEMFC systems are analyzed in detail. Third, the ANN ensemble for the fault diagnosis is built and modeled. This model is trained and tested by the data. The test result shows that, compared with the previous method for fault diagnosis of PEMFC systems, the proposed fault diagnosis method has higher diagnostic rate and generalization ability. Moreover, the partial structure of this method can be altered easily, along with the change of the PEMFC systems. In general, this method for diagnosis of PEMFC has value for certain applications. - Highlights: • We analyze the principles and mechanisms of the four faults in PEMFC (proton exchange membrane fuel cell) system. • We design and model an ANN (artificial neural network) ensemble method for the fault diagnosis of PEMFC system. • This method has high diagnostic rate and strong generalization ability

  4. Surface stability and conductivity of a high Cr and Ni austenitic stainless steel plates for PEMFC

    Institute of Scientific and Technical Information of China (English)

    TIAN Rujin; SUN Juncai; WANG Jianli

    2006-01-01

    In order to use stainless steel as bipolar plate for PEMFC, electrochemical behavior of a high Cr and Ni austenitic stainless steel was studied in the solutions containing different concentration of H2SO4 and 2 mg·L-1 F-, and interfacial contact resistance was measured after corrosion tests. The experimental results show that the passive current density lowers with decreasing the concentration of H2SO4. The interfacial contact resistance between carbon paper and passive film formed in the simulated PEMFC environment is higher than the goal of bipolar plate for PEMFC. Surface conductivity should be further reduced by surface modification.

  5. Exergy analysis of the woody biomass Stirling engine and PEM-FC combined system with exhaust heat reforming

    Energy Technology Data Exchange (ETDEWEB)

    Obara, Shin' ya; Tanno, Itaru [Department of Mechanical Engineering, Tomakomai National College of Technology, 443 Nishikioka, Tomakomai, Hokkaido 0591275 (Japan); Kito, Shunsuke [Department of Mechanical Engineering, Toyota National College of Technology, Eisei-cho, 2-1 Toyota, Aichi 4718525 (Japan); Hoshi, Akira; Sasaki, Seizi [Department of Mechanical Engineering, Ichinoseki National College of Technology, Takanashi, Hagisho, Ichinoseki, Iwate 0218511 (Japan)

    2008-05-15

    The woody biomass Stirling engine (WB-SEG) is an external combustion engine that outputs high-temperature exhaust gases. It is necessary to improve the exergy efficiency of WB-SEG from the viewpoint of energy cascade utilization. So, a combined system that uses the exhaust heat of WB-SEG for the steam reforming of city gas and that supplies the produced reformed gas to a proton exchange membrane fuel cell (PEM-FC) is proposed. The energy flow and the exergy flow were analyzed for each WB-SEG, PEM-FC, and WB-SEG/PEM-FC combined system. Exhaust heat recovery to preheat fuel and combustion air was investigated in each system. As a result, (a) improvement of the heat exchange performance of the woody biomass combustion gas and engine is observed, (b) reduction in difference in the reaction temperature of each unit, and (c) removal of rapid temperature change of reformed gas are required in order to reduce exergy loss of the system. The exergy efficiency of the WB-SEG/PEM-FC combined system is superior to EM-FC. (author)

  6. Dynamic model used to investigate the influence of operating conditions on the behavior of commercial PEMFC

    International Nuclear Information System (INIS)

    Numerical modelling plays an important role in the development and the improvement of fuel cells. This paper presents a model which is used to analyze and to understand the behavior of a commercial Proton Exchange Membrane Fuel Cell (PEMFC) under variable operating conditions. These working conditions will also be investigated by means of properly designed experimental tests, which involve different electrical polarization situations. The study of fuel cell behavior in transient conditions gives information and suggests strategies for fuel cell optimization. Nowadays many numerical models are available to describe steady state behavior but models capable of predicting transient phenomena are very few. The dynamic model discussed in this paper is used to investigate the cell behavior (voltage variations over current density, i.e. dynamic polarization curves) for different cell temperature, species stoichiometry, species inlet temperature and humidity. Experimental tests will consist in the study of the dynamic polarization curve which gives information on fuel cell behavior at different operating conditions. The main factors affecting the performance of a commercial fuel cell will be analyzed. The design of experiments (DOE) technique will lead us to the development of some regression models which can accurately reproduce the influence of each parameter over the fuel cell voltage and consequently to estimate the combined effects. The regression models can also be used to check the results of the numerical models. Numerical modeling is essential in order to reduce the experimental time required to predict a complex system behavior in unsteady operating conditions and hence to reduce the economical impact of such investigation in the industrial context. In the present paper, the numerical simulation results are compared with those due to the experimental results and the main conclusions are pointed out. (authors)

  7. Steady State Multiplicity in a Polymer Electrolyte Membrane Fuel Cell

    OpenAIRE

    Chia, Ee-Sunn J.; Benziger, Jay B.; Kevrekidis, Ioannis G.

    2003-01-01

    A simplified differential reactor model that embodies the essential physics controlling PEM fuel cell (PEM-FC) dynamics is presented. A remarkable analogy exists between water management in the differential PEM-FC and energy balance in the classical exothermic stirred tank reactor. Water, the reaction product in the PEM-FC autocatalytically accelerates the reaction rate by enhancing proton transport through the PEM. Established analyses of heat autocatalyticity in a CSTR are modified to prese...

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

    OpenAIRE

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

    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 ...

  9. Stacks with TiN/titanium as the bipolar plate for PEMFCs

    International Nuclear Information System (INIS)

    Proton exchange membrane fuel cell (PEMFC) is a potential alternative for the internal combustion engine. But many problems, such as metallic bipolar plate instead of graphite bipolar plate to decrease the cost, should be solved before its application. Based on the previous results that single cell with TiN/Ti as bipolar plates shows high performance and enough long-time durability, the progress on the stacks with TiN/Ti as bipolar plates is reported in this manuscript. Till now seldom report is focused on stacks because of the complicated processing technique, especially for that with TiN/Ti as bipolar plate. The flow field in the plate is punched from titanium deformation, and two plates are welded by laser welding to form one piece of bipolar plate. The adopted processing techniques for stacks with TiN/Ti as bipolar plate exhibit advantage and feasibility in industry. The power density by weight for the stack is as high as 1353 W kg−1, although it still has space to be improved. Next work should be focused on the design of flow channel parameters and flow field type based on plastic deformation of metal materials. -- Highlights: ► The progress on the stacks with TiN/Ti as bipolar plates is reported. ► The adopted processing techniques exhibit feasibility in industry. ► The power density by weight for the stack is as high as 1353 W kg−1.

  10. Biomimetic Synthesis of Noble Metal Nanoparticles and Their Applications as Electro-catalysts in Fuel Cells

    OpenAIRE

    Li, Yujing

    2012-01-01

    Today, proton electrolyte membrane fuel cell (PEMFC) and direct methanol fuel cell (DMFC) are attractive power conversion devices that generate fairly low or even no pollution, and considered to be potential to replace conventional fossil fuel based power sources on automobiles. The operation and performance of PEMFC and DMFC depend largely on electro-catalysts positioned between the electrode and the membranes. The most commonly used electro-catalysts for PEMFC and DMFC are Pt-based noble me...

  11. Spraying Techniques for Large Scale Manufacturing of PEM-FC Electrodes

    Science.gov (United States)

    Hoffman, Casey J.

    Fuel cells are highly efficient energy conversion devices that represent one part of the solution to the world's current energy crisis in the midst of global climate change. When supplied with the necessary reactant gasses, fuel cells produce only electricity, heat, and water. The fuel used, namely hydrogen, is available from many sources including natural gas and the electrolysis of water. If the electricity for electrolysis is generated by renewable energy (e.g., solar and wind power), fuel cells represent a completely 'green' method of producing electricity. The thought of being able to produce electricity to power homes, vehicles, and other portable or stationary equipment with essentially zero environmentally harmful emissions has been driving academic and industrial fuel cell research and development with the goal of successfully commercializing this technology. Unfortunately, fuel cells cannot achieve any appreciable market penetration at their current costs. The author's hypothesis is that: the development of automated, non-contact deposition methods for electrode manufacturing will improve performance and process flexibility, thereby helping to accelerate the commercialization of PEMFC technology. The overarching motivation for this research was to lower the cost of manufacturing fuel cell electrodes and bring the technology one step closer to commercial viability. The author has proven this hypothesis through a detailed study of two non-contact spraying methods. These scalable deposition systems were incorporated into an automated electrode manufacturing system that was designed and built by the author for this research. The electrode manufacturing techniques developed by the author have been shown to produce electrodes that outperform a common lab-scale contact method that was studied as a baseline, as well as several commercially available electrodes. In addition, these scalable, large scale electrode manufacturing processes developed by the author are

  12. 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.

  13. 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.

  14. Transient analysis of carbon monoxide transport phenomena and adsorption kinetics in HT-PEMFC during dynamic current extraction

    International Nuclear Information System (INIS)

    Highlights: • Increasing the fuel cell temperature reduces outlet CO concentration. • Increasing the CO inlet (initial) concentration increases outlet CO concentration. • Increasing current density step and dwell time increases outlet CO concentration. • Increasing in the CL and GDL porosities reduces outlet CO concentration. - Abstract: This paper investigates the transport phenomena of carbon monoxide (CO) and adsorption kinetics, in a high-temperature proton exchange membrane fuel cell (HT-PEMFC) during step-wise current extraction (step-change in current extraction). Step-wise current extraction is a common process done to accommodate a sudden power surge during an operation. Since HT-PEMFCs are capable of handling high impurity of CO, hydrogen fuel that is contaminated with trace amount of CO is usually considered for commercial benefits. Thus, a transient three-dimensional isothermal anodic electro-kinetic numerical model is developed to determine the effect of operating parameters such as fuel cell temperature, CO inlet (initial) concentration, step-change of current density and dwell time on the transport phenomena of CO and adsorption kinetics. In addition, geometrical factors such as the catalyst layer (CL) and gas diffusion layer (GDL) porosity are also varied as well. The results show that the above-mentioned operating parameters can affect the maximum CO concentration at the CL, especially at the outlet of the channel. Specifically, a reduction of fuel cell temperature can significantly increase the CO concentration near the outlet, while increasing CO inlet (initial) concentration, step-change amplitude of current density and current density dwell time can cause an increase in CO concentration at the outlet, albeit to different extent. In addition, the increase in the porosity of CL and GDL, results in the reduction of the maximum CO concentration at the outlet, albeit to different extent. In addition, the CO and hydrogen surface coverage

  15. 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.

  16. Modified pulse electrodeposition of Pt nanocatalyst as high-performance electrode for PEMFC

    Science.gov (United States)

    Fouda-Onana, F.; Guillet, N.; AlMayouf, A. M.

    2014-12-01

    Low platinum loading electrode was successfully deposited by a modified pulse galvanic signal in H2PtCl6 electrolyte using carbon black as support directly on a GDL (Gas Diffusion Layer). SEM images of the deposition were composed by rough Pt particles of 50 nm leading to specific electrochemical surface area of 53 m2 g-1. In spite of large particle size and a low cathode loading of 0.12 mg cm-2, the proton exchange membrane fuel cell (PEMFC) fed with humidified H2 and O2 at 80 °C, 1.5 absolute bar reached 0.2 mA cmPt-2 and 0.1 A mg-1 at 0.9 VIR-free which were twice higher than a reference membrane electrodes assembly (MEA) with a cathode loaded at 0.4 mgPt.cm-2. Such an active cathode electrode may be ascribed to a higher utilization rate of the platinum caused by an efficient catalyst deposition by electrochemical route.

  17. Catalyst layers for PEMFC manufactured by flexography printing process: performances and structure

    Energy Technology Data Exchange (ETDEWEB)

    Bois, C.; Blayo, A.; Chaussy, D. [Laboratory of Pulp and Paper Science and Graphic Arts (LGP2) (UMR 5518 CNRS-CTP-INPG), Grenoble Institute of Technology (INP Grenoble - PAGORA), St Martin d' Heres (France); Vincent, R.; Mercier, A.G.; Nayoze, C. [Commissariat a l' Energie Atomique et aux Energies Alternatives (CEA)/DRT/LITEN, Laboratoire des Composants Piles a Combustible, Electrolyse et Modelisation (LCPEM), Grenoble (France)

    2012-04-15

    This article focuses on the potential of a classic printing process, flexography, for manufacturing proton exchange membrane fuel cells (PEMFCs). Gas diffusion electrodes (GDEs) are produced by deposition of a water-based catalyst ink on a gas diffusion layer (GDL). The affinity between the ink and the GDL is quantified. Thus, the strong hydrophobic character of the GDL and the poor printability of the ink are demonstrated. However, the permeability of the GDL allows developing a multilayer protocol. The deposition by superimposition of ink layers allows control of the platinum amount and to obtain catalyst layers with a similar density of platinum nanoparticles to coated samples. At similar platinum loading, flexography and coating made catalyst layers offer similar performances, which confirm the relevance of flexography in catalyst layer manufacturing. Structural characterization shows that manufacturing protocol and process has an influence on catalyst layer microstructure. However, catalyst layer cracking and aggregation are increased with the catalyst layer thickness, diminishing the charge and gas diffusion into the catalyst layer resulting in performance degradation. Consequently, a catalyst layer with 0.46 mgPt cm{sup -2} reaches similar performances to catalyst layers with 1.77 and 2.01 times less platinum loading. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  18. Experimental Investigation and Discussion on the Mechanical Endurance Limit of Nafion Membrane Used in Proton Exchange Membrane Fuel Cell

    OpenAIRE

    Yang Xiao; Chongdu Cho

    2014-01-01

    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 ...

  19. “Distributed hybrid” MH–CGH2 system for hydrogen storage and its supply to LT PEMFC power modules

    International Nuclear Information System (INIS)

    Highlights: • Prototype hydrogen storage and supply system for LTPEMFC applications was developed. • Combination of MH and CGH2 tanks with common gas manifold was used. • Thermal coupling of fuel cell stack and MH tank was applied. • The system uses AB2-type MH; H2 equilibrium pressure ∼10 bar at room temperature. • Shorter H2 charge time and stable H2 supply at a fluctuating load were observed. - Abstract: This paper describes the layout and presents the results of the testing of a novel prototype “distributed hybrid” hydrogen storage and supply system that has the potential to be used for Low Temperature Proton Exchange Membrane Fuel Cell (LT-PEMFC) applications. The system consists of individual Metal Hydride (MH) and Compressed Gas (CGH2) tanks with common gas manifold, and a thermal management system where heat exchanger of the liquid heated-cooled MH tank is integrated with the cooling system of the LT-PEMFC BoP. The MH tank is filled with a medium-stability AB2-type MH material (H2 equilibrium pressure of about 10 bar at room temperature). This innovative solution allows for (i) an increase in hydrogen storage capacity of the whole gas storage system and the reduction of H2 charge pressure; (ii) shorter charging times in the refuelling mode and smoother peaks of H2 consumption during its supply to the fuel cell stack; (iii) the use of standard parts with simple layout and lower costs; and (iv) adding flexibility in the layout and placement of the components of the hydrogen storage and supply system

  20. “Distributed hybrid” MH–CGH2 system for hydrogen storage and its supply to LT PEMFC power modules

    Energy Technology Data Exchange (ETDEWEB)

    Lototskyy, M., E-mail: mlototskyy@uwc.ac.za [HySA Systems Competence Centre, South African Institute for Advanced Materials Chemistry, Faculty of Natural Sciences, University of the Western Cape, Private Bag X17, Bellville 7535 (South Africa); Tolj, I.; Davids, M.W.; Bujlo, P. [HySA Systems Competence Centre, South African Institute for Advanced Materials Chemistry, Faculty of Natural Sciences, University of the Western Cape, Private Bag X17, Bellville 7535 (South Africa); Smith, F. [Impala Platinum Ltd, Springs (South Africa); Pollet, B.G. [HySA Systems Competence Centre, South African Institute for Advanced Materials Chemistry, Faculty of Natural Sciences, University of the Western Cape, Private Bag X17, Bellville 7535 (South Africa)

    2015-10-05

    Highlights: • Prototype hydrogen storage and supply system for LTPEMFC applications was developed. • Combination of MH and CGH2 tanks with common gas manifold was used. • Thermal coupling of fuel cell stack and MH tank was applied. • The system uses AB2-type MH; H2 equilibrium pressure ∼10 bar at room temperature. • Shorter H2 charge time and stable H2 supply at a fluctuating load were observed. - Abstract: This paper describes the layout and presents the results of the testing of a novel prototype “distributed hybrid” hydrogen storage and supply system that has the potential to be used for Low Temperature Proton Exchange Membrane Fuel Cell (LT-PEMFC) applications. The system consists of individual Metal Hydride (MH) and Compressed Gas (CGH2) tanks with common gas manifold, and a thermal management system where heat exchanger of the liquid heated-cooled MH tank is integrated with the cooling system of the LT-PEMFC BoP. The MH tank is filled with a medium-stability AB{sub 2}-type MH material (H{sub 2} equilibrium pressure of about 10 bar at room temperature). This innovative solution allows for (i) an increase in hydrogen storage capacity of the whole gas storage system and the reduction of H{sub 2} charge pressure; (ii) shorter charging times in the refuelling mode and smoother peaks of H{sub 2} consumption during its supply to the fuel cell stack; (iii) the use of standard parts with simple layout and lower costs; and (iv) adding flexibility in the layout and placement of the components of the hydrogen storage and supply system.

  1. PEMFC分散发电系统的压力控制研究%Pressure control of PEMFC distributed power generator

    Institute of Scientific and Technical Information of China (English)

    张颖颖; 曹广益; 朱新坚

    2006-01-01

    Control design is important for PEMFC (proton exchange membrane fuel cell) distributed power generator to satisfy user requirement for safe and stable operation.For a complex multi-variable dynamic system, a dynamic simulation model is first established.In view of close coupling and non-linear relationships between variables, the intelligent auto-adapted PI decoupling control method is used.From the simulation results it is found that, by bringing quadratic performance index in the single neuron, constructing adaptive PI controller, and adjusting gas flow rates through the second pressure relief valve and air compressor coordinately, both anode and cathode pressures can be maintained at ideal levels.

  2. The effect of thermal treatment on structure and surface composition of PtCo electro-catalysts for application in PEMFCs operating under automotive conditions

    OpenAIRE

    Stassi, A.; Gatto, I.; Monforte, G.; Baglio, V.; Passalacqua, E.; Antonucci, V.; Aricò, A.S.

    2012-01-01

    International audience Structure and surface characteristics of carbon-supported PtCo cathode electro-catalysts were investigated to evaluate their performance and resistance to degradation under high temperature (∼110 ◦C) operation in a polymer electrolyte membrane fuel cell (PEMFC). Two different thermal treatments were investigated, i.e. 600 ◦C and 800 ◦C causing the occurrence of a disordered face-centered cubic (fcc) structure and a primitive cubic ordered (L12) phase. A specific coll...

  3. Dynamic behaviour of a PEM fuel cells for stationary applications

    International Nuclear Information System (INIS)

    We present the results of an investigation of the behavior of a proton exchange membrane fuel cells (PEMFC) under fast load commutations. These results will be used to integrate the PEMFC in the renewable energy (RE) system based on hydrogen developed at the Institut de recherche sur l'hydrogene (IRH). (author)

  4. 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.

  5. Characterization of the operational parameters of a H{sub 2}/air micro PEMFC with different flow fields by impedance spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Hsieh, Shou-Shing; Yang, Sheng-Huang; Feng, Chih-Lun [Department of Mechanical and Electro Mechanical Engineering, National Sun Yat-Sen University, Kaohsiung, Taiwan (ROC)

    2006-11-08

    The operational parameters of a H{sub 2}/air micro proton exchange membrane fuel cell (PEMFC) with different flow configurations (mesh, serpentine, and interdigitated) were investigated by impedance spectroscopy. The operational parameters include the cell operating temperature and the anode backpressure. The above parameters affected the high frequency straight line as well as the medium frequency and low frequency arcs. The influence in terms of impedance on the dynamic response of the present H{sub 2}/air micro fuel cell under different operating conditions and flow geometry were quantitatively measured, which it allows insight into the nature of these effects and consequently a better understanding of the micro PEM fuel cell system that could be helpful for the design and operation of the fuel cell. (author)

  6. Prognostics of Proton Exchange Membrane Fuel Cells stack using an ensemble of constraints based connectionist networks

    Science.gov (United States)

    Javed, Kamran; Gouriveau, Rafael; Zerhouni, Noureddine; Hissel, Daniel

    2016-08-01

    Proton Exchange Membrane Fuel Cell (PEMFC) is considered the most versatile among available fuel cell technologies, which qualify for diverse applications. However, the large-scale industrial deployment of PEMFCs is limited due to their short life span and high exploitation costs. Therefore, ensuring fuel cell service for a long duration is of vital importance, which has led to Prognostics and Health Management of fuel cells. More precisely, prognostics of PEMFC is major area of focus nowadays, which aims at identifying degradation of PEMFC stack at early stages and estimating its Remaining Useful Life (RUL) for life cycle management. This paper presents a data-driven approach for prognostics of PEMFC stack using an ensemble of constraint based Summation Wavelet- Extreme Learning Machine (SW-ELM) models. This development aim at improving the robustness and applicability of prognostics of PEMFC for an online application, with limited learning data. The proposed approach is applied to real data from two different PEMFC stacks and compared with ensembles of well known connectionist algorithms. The results comparison on long-term prognostics of both PEMFC stacks validates our proposition.

  7. 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)

  8. Determination of the pore size distribution of micro porous layer in PEMFC using pore forming agents under various drying conditions

    Energy Technology Data Exchange (ETDEWEB)

    Chun, Jeong Hwan; Park, Ki Tae; Jo, Dong Hyun; Lee, Ji Young; Kim, Sang Gon; Kim, Sung Hyun [Department of Chemical and Biological Engineering, Korea University, 1 Anam-Dong, Seongbuk-Ku, Seoul 136-713 (Korea); Lee, Eun Sook; Jyoung, Jy-Young [Energy Research Center, HyupJin I and C Co., LTD, 143-1 Gwelang-Ri, Jungnam-Myun, Hwasung-Si, Kyunggi-Do (Korea)

    2010-10-15

    In this paper, the effect of the pore size distribution of a micro-porous layer (MPL) on the performance of polymer electrolyte membrane fuel cells (PEMFC) was investigated using self-made gas diffusion layers (GDLs) with different MPLs for which the pore size distribution was modified using pore forming agents under different drying conditions. When MPL dried at high temperature, more macro pores, approximately 1,000-20,000 nm in diameter, and less micro pores, below 100 nm, were observed relative to when MPL was dried at low temperature. Self-made GDLs were characterized by a field-emission scanning electron microscope (FE-SEM), mercury porosimetry and self-made gas permeability measurement equipment. The performance of the single cells was measured under two different humidification conditions. The results demonstrate that the optimum pore size distribution of MPL depended on the cell operating humidification condition. The MPL dried at high temperature performed better than the MPL dried at low temperature under a low humidification condition; however, MPL dried at low temperature performed better under a high humidification condition. (author)

  9. 基于USB通信的PEMFC内阻在线测试系统设计%Online Testing System of PEMFC Internal Resistance Based on USB Communication

    Institute of Scientific and Technical Information of China (English)

    李小君; 陈启宏

    2012-01-01

    The resistance line for the PEMFC test system was designed to complete a high - precision programmable AC excitation source. The major controller of the excitation source was LM3S5749 high - performance ARM processing chip. And a Visual C + +6.0 USB communication protocol was proposed and realized to meet the actual needs of high - speed data acquisition system. The test system can avoid overheads resulted from frequently task scheduling. At the same time it can timely response to the hardware interrupts,hardware polling and other special assignments,which meets the real -time nature of the project needs.%针对PEMFC(proton exchange membrane fuel cell)内阻在线测试系统,设计了以TMLM3S5749高性能ARM处理器为主控制器的高精度程控交流激励源,满足了高速数据采集系统的实际需要,给出了以Visual C++6.0为开发平台的USB通信协议的设计与实现方法,测试系统可以减少由于任务的频繁调度所带来的开销,同时又能够对硬件中断和硬件轮询等特别任务进行及时响应,符合项目的实时性需求.

  10. Corrosion Behavior of Passivated 316LSS with Ag Coating as PEMFC Bipolar Plate

    Directory of Open Access Journals (Sweden)

    Naibao Huang

    2011-01-01

    Full Text Available A new chemical passivation technique, which contained 20 g/L hydrogen peroxide, 3.75 g/L sodium silicate, 1.25 g/L sodium carbonate, 3.75 g/L lactic acid and 0.75 g/L 8-hydroxyquinoline, was used to modify 316 stainless steel with Ag coating (Ag-coated 316SS as PEMFC bipolar plates. The results indicated that the compact passive film had been obtained on the surface of Ag-coated 316SS. The passivation process could not only increase contact angle (from 58∘ to 104∘ but also decreased pinhole defects of Ag-coated 316SS. Electrochemical test manifested that the passivation process could reduce Ag-coated 316SS's double layer capacitance (Cd, and increase its charge transfer resistance. So, it provided significant protection against corrosion for Ag-coated 316SS in PEMFC environment.

  11. 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.

  12. 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

    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...

  13. Terrorismo vis à vis Desenvolvimento

    OpenAIRE

    Cerdeira, José

    2012-01-01

    O terrorismo é um fenómeno que representa uma ameaça à segurança internacional e que está frequentemente associada ao nível de desenvolvimento dos Estados, importando verificar a sua dinâmica com a frequência de atentados, vitimas e a motivação dos perpetradores de atos terroristas. Para tal desiderato, recorremos ao processo metodológico proposto por Quivy & Campenhoudt (2005), recorrendo à bibliografia de autores reconhecidos e à análise de dados disponibilizados por bases de dados credí...

  14. Desenvolvimento motor, afecto e pensamento

    OpenAIRE

    Salgueiro, Emílio Eduardo Guerra

    1988-01-01

    O autor procura mostrar a íntima relação que vê entre o desenvolvimento motor da criança em experiências emocionais com que ela se defronta, desde a nascimento. Cada acto motor tem uma finalidade, que deriva do entendimento emocional que a criança consegue tirar de cada situação, e da caparcidade de resposta que vai adquirindo. Há uma linha de amadurecimento emocional, em paralelo interarctivo com uma linha de amadurecimento motor, e desta interacção vai nascer u...

  15. Employment of fluorine doped zinc tin oxide (ZnSnOx:F) coating layer on stainless steel 316 for a bipolar plate for PEMFC

    International Nuclear Information System (INIS)

    Highlights: → Preparation of fluorine doped tin oxide (SnOx:F) and fluorine doped zinc tin oxide (ZnSnOx:F) coating layer on the surface of stainless steel 316 bipolar plate for PEMFCs (Proton Exchange Membrane Fuel Cells). → Evaluations of the corrosion resistance and the interfacial contact resistance of the bare, SnOx:F and ZnSnOx:F thin film coated stainless steel 316 bipolar plates. → Evaluation of single cell performance such as cell voltage and power density using bare stainless steel, SnOx:F and ZnSnOx:F film coated bipolar plates. - Abstract: The investigation of the electrochemical characteristics of the fluorine doped tin oxide (SnOx:F) and fluorine doped zinc tin oxide (ZnSnOx:F) was carried out in the simulated PEMFC environment and bare stainless steel 316 was used as a reference. The results showed that the ZnSnOx:F coating enhanced both the corrosion resistance and interfacial contact resistance (ICR). The corrosion current for ZnSnOx:F was 1.2 μA cm-2 which was much lower than that of bare stainless steel of 50.16 μA cm-2. The ZnSnOx:F coated film had the smallest corrosion current due to the formation of a tight surface morphology with very few pin-holes. The ZnSnOx:F coated film exhibited the highest values of the cell voltage and power density due to its having the lowest ICR values.

  16. High-performance membrane-electrode assembly with an optimal polytetrafluoroethylene content for high-temperature polymer electrolyte membrane fuel cells

    DEFF Research Database (Denmark)

    Jeong, Gisu; Kim, MinJoong; Han, Junyoung;

    2016-01-01

    Although high-temperature polymer electrolyte membrane fuel cells (HT-PEMFCs) have a high carbon monoxide tolerance and allow for efficient water management, their practical applications are limited due to their lower performance than conventional low-temperature PEMFCs. Herein, we present a high...

  17. Conductive and corrosion behaviors of silver-doped carbon-coated stainless steel as PEMFC bipolar plates

    Institute of Scientific and Technical Information of China (English)

    Ming Liu; Hong-feng Xu; Jie Fu; Ying Tian

    2016-01-01

    Ni–Cr enrichment on stainless steel SS316L resulting from chemical activation enabled the deposition of carbon by spraying a stable suspension of carbon nanoparticles; trace Ag was depositedin situ to prepare a thin continuous Ag-doped carbon film on a porous carbon-coated SS316L substrate. The corrosion resistance of this film in 0.5 mol·L−1 H2SO4 solution containing 5 ppm F− at 80°C was inves-tigated using polarization tests. The results showed that the surface treatment of the SS316L strongly affected the adhesion of the carbon coating to the stainless steel. Compared to the bare SS316L, the Ag-doped carbon-coated SS316L bipolar plate was remarkably more stable in both the anode and cathode environments of proton exchange membrane fuel cell (PEMFC) and the interface contact resistance between the specimen and Toray 060 carbon paper was reduced from 333.0 mΩ·cm2 to 21.6 mΩ·cm2 at a compaction pressure of 1.2 MPa.

  18. Electrochemical Behavior of Niobium Electrodeposited 316 Stainless Steel Bipolar Plate for PEMFC in Choline Chloride Based Ionic Liquids

    Institute of Scientific and Technical Information of China (English)

    CAO Caihong; LIANG Chenghao; HUANG Naibao

    2015-01-01

    Niobium was electrodeposited on 316 stainless steel bipolar plates of a fuel cell in water and air-stable choline chloride based ionic liquids. The electrochemical corruption property of bipolar plates in simulated PEMFC environment was investigated. It was showed that the plating iflm was distributed on the surface of 316 stainless steel like isolated islands with height less than 50 nm. The XPS, XRD results showed that a smooth and strong chemical inert iflm of NbO and Nb2O5 was formed on the surface of 316 stainless steel. In simulated cathodic condition, the corrosion potential of Nb coated stainless steel was improved by 244 mV, whilst in an anodic condition, it was improved by 105 mV. The current densities for the coated 316 stainless steel were decreased to 2.479 4 µA•cm-2 from 14.810 µA•cm-2 at-0.1 V and to 0.576 µA•cm-2 from 13.417 µA/•cm-2 at 0.6 V, respectively. It was implied that the niobium coating effectively decreased the corrosion rate. The results of the electrochemical tests indicated that the corrosion resistance of stainless steel was greatly improved after coated with niobium.

  19. Conductive and corrosion behaviors of silver-doped carbon-coated stainless steel as PEMFC bipolar plates

    Science.gov (United States)

    Liu, Ming; Xu, Hong-feng; Fu, Jie; Tian, Ying

    2016-07-01

    Ni-Cr enrichment on stainless steel SS316L resulting from chemical activation enabled the deposition of carbon by spraying a stable suspension of carbon nanoparticles; trace Ag was deposited in situ to prepare a thin continuous Ag-doped carbon film on a porous carbon-coated SS316L substrate. The corrosion resistance of this film in 0.5 mol·L-1 H2SO4 solution containing 5 ppm F- at 80°C was investigated using polarization tests. The results showed that the surface treatment of the SS316L strongly affected the adhesion of the carbon coating to the stainless steel. Compared to the bare SS316L, the Ag-doped carbon-coated SS316L bipolar plate was remarkably more stable in both the anode and cathode environments of proton exchange membrane fuel cell (PEMFC) and the interface contact resistance between the specimen and Toray 060 carbon paper was reduced from 333.0 mΩ·cm2 to 21.6 mΩ·cm2 at a compaction pressure of 1.2 MPa.

  20. Testing and model-aided analysis of a 2 kW el PEMFC CHP-system

    Science.gov (United States)

    König, P.; Weber, A.; Lewald, N.; Aicher, T.; Jörissen, L.; Ivers-Tiffée, E.; Szolak, R.; Brendel, M.; Kaczerowski, J.

    A prototype PEMFC CHP-system (combined heat and power) for decentralised energy supply in domestic applications has been installed in the Fuel Cell Testing Laboratory at the Institut für Werkstoffe der Elektrotechnik (IWE), Universität Karlsruhe (TH). The system, which was developed at the Zentrum für Sonnenenergie- und Wasserstoff-Forschung ZSW, Ulm (FC-stack) and the Fraunhofer-Institut für Solare Energiesysteme ISE, Freiburg (reformer) is operated and tested in close cooperation with the Stadtwerke Karlsruhe. The tests are carried out as part of the strategic project EDISon, which is supported by the German Federal Ministry of Economics and Technology (BMWA). The performance of the system is evaluated for different operating conditions. The tests include steady state measurements under different electrical and thermal loads as well as an analysis of the dynamic behaviour of the system during load changes. First results of these steady state and dynamic operation characteristics will be presented in this paper.

  1. Characterisation of fuel cell state using Electrochemical Impedance Spectroscopy analysis

    OpenAIRE

    Primucci, Mauricio; Ferrer Arnau, Lluís Jordi; Serra, Maria; Riera, Jordi

    2008-01-01

    One of the most demanding research topics related to the Polymer Electrolyte Membrane Fuel Cell (PEMFC) concerns its reliability. Apart from the security aspects, it is basic to have a diagnosis of the internal state of the PEMFC in order to correct and optimise its operation. The Fuel cell state and response depends on the imposed operating conditions, which are mainly given by temperatures, pressures, humidity, reactants concentrations and current. This work explores the use of fuel cell ex...

  2. 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.)

  3. High Molecular Weight Polybenzimidazole Membranes for High Temperature PEMFC

    DEFF Research Database (Denmark)

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

    2014-01-01

    Da with good solubility in organic solvents. Membranes fabricated from the polymers were systematically characterized in terms of oxidative stability, acid doping and swelling, conductivity, mechanical strength and fuel cell performance and durability. With increased molecular weights the polymer...... membranes showed enhanced chemical stability towards radical attacks under the Fenton test, reduced volume swelling upon the acid doping and improved mechanical strength at acid doping levels of as high as about 11 mol H3PO4 per molar repeat polymer unit. The PBI‐78kDa/10.8PA membrane, for example......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...

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

    International Nuclear Information System (INIS)

    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

  5. Investigation of PEMFC MEAs for ultra-high CO reformate

    Energy Technology Data Exchange (ETDEWEB)

    Ball, S.

    2004-07-01

    This report presents the findings of a study designing and testing a series of catalysts for proton exchange membrane (PEM) fuel cells which can use as anode fuel the hydrogen-rich output from the reforming of hydrocarbon fuel after carbon monoxide (CO) clean up. A trade off between a reduction in the complexity of the system and the loss in the performance of the anode due to poisoning by carbon monoxide was explored, and enhancement of the reformer and CO clean up catalysts, and optimization of the anode formulation were investigated. Details are given of the carbon supported platinum-molybdenum catalyst, the fabrication of bilayer anodes, and the efficiencies of high-CO and low-CO PEM fuel cells.

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

    International Nuclear Information System (INIS)

    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

  7. Evaluation of Electrochemical Characteristics on Graphene Coated Austenitic and Martensitic Stainless Steels for Metallic Bipolar Plates in PEMFC Fabricated with Hydrazine Reduction Methods

    Energy Technology Data Exchange (ETDEWEB)

    Cha, Seong-Yun; Lee, Jae-Bong [School of Advanced Materials Engineering, Kookmin University, Seoul (Korea, Republic of)

    2016-04-15

    Graphene was coated on austenitic and martensitic stainless steels to simulate the metallic bipolar plate of proton exchange membrane fuel cell (PEMFC). Graphene oxide (GO) was synthesized and was reduced to reduced graphene oxide (rGO) via a hydrazine process. rGO was confirmed by FE-SEM, Raman spectroscopy and XPS. Interfacial contact resistance (ICR) between the bipolar plate and the gas diffusion layer (GDL) was measured to confirm the electrical conductivity. Both ICR and corrosion current density decreased on graphene coated stainless steels. Corrosion resistance was also improved with immersion time in cathodic environments and satisfied the criteria of the Department of Energy (DOE), USA. The total concentrations of metal ions dissolved from graphene coated stainless steels were reduced. Furthermore hydrophobicity was improved by increasing the contact angle.

  8. Corrosion Behavior of Passivated 316LSS with Ag Coating as PEMFC Bipolar Plate

    OpenAIRE

    Naibao Huang; Chenghao Liang; Hongtao Wang; Lishuang Xu; Hongfeng Xu

    2011-01-01

    A new chemical passivation technique, which contained 20 g/L hydrogen peroxide, 3.75 g/L sodium silicate, 1.25 g/L sodium carbonate, 3.75 g/L lactic acid and 0.75 g/L 8-hydroxyquinoline, was used to modify 316 stainless steel with Ag coating (Ag-coated 316SS) as PEMFC bipolar plates. The results indicated that the compact passive film had been obtained on the surface of Ag-coated 316SS. The passivation process could not only increase contact angle (from 58∘ to 104∘) but also decreased pinhole...

  9. Pile à combustible PEMFC et SOFC. Description et gestion du système

    OpenAIRE

    CANDUSSO, D; Glises, R.; Hissel, D.; KAUFFMANN, JM; PERA, MC

    2007-01-01

    Les piles à combustible PEMFC et SOFC font l'objet de deux articles: description et gestion du système [BE 8 595] et transferts de chaleur et de masse [BE 8 596]. Les piles à combustible dont le principe de fonctionnement, mis en oeuvre par Sir William Grove, date de 1839, sont restées pendant de très nombreuses années des dispositifs de laboratoire. Au tournant des années 1960, elles sont devenues des générateurs d'énergie pour les applications spatiales. Leur intérêt pour des applications p...

  10. 质子交换膜燃料电池电堆的动态热模型及其温度控制%Dynamic Thermal Model and Temperature Control of Proton Exchange Membrane Fuel Cell Stack

    Institute of Scientific and Technical Information of China (English)

    邵庆龙; 卫东; 曹广益; 朱新坚

    2005-01-01

    A dynamic thermal transfer model of a proton exchange membrane fuel cell (PEMFC) stack is developed based on energy conservation in order to reach better temperature control of PEMFC stack. Considering its uncertain parameters and disturbance, we propose a robust adaptive controller based on backstepping algorithm of Lyaponov function. Numerical simulations indicate the validity of the proposed controller.

  11. 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.

  12. Composite plasma polymerized sulfonated polystyrene membrane for PEMFC

    International Nuclear Information System (INIS)

    Highlights: • Methyl methane sulfonate (MMS) is used as the sulfonating agent. • The proton conductivity of the membrane is found to be 0.141 S cm−1. • Power density of fuel cell with styrene/MMS membrane is 0.5 W cm−2. • The membrane exhibits thermal stability up to 140 °C. - Abstract: This work presents the introduction of an organic compound methyl methane sulfonate (MMS) for the first time in fabrication of polystyrene based proton exchange membrane (PEM) by plasma polymerization process. The membrane is fabricated by co-polymerizing styrene and MMS in capacitively coupled continuous RF plasma. The chemical composition of the plasma polymerized polymer membrane is investigated using Fourier Transform Infrared Spectroscopy which reveals the formation of composite structure of styrene and MMS. The surface morphology studied using AFM and SEM depicts the effect of higher partial pressure of MMS on surface topography of the membrane. The proton transport property of the membrane studied using electrochemical impedance spectroscopy shows the achievement of maximum proton conductivity of 0.141 S cm−1 which is comparable to Nafion 117 membrane. Fuel cell performance test of the synthesized membrane shows a maximum power density of 500 mW cm−2 and current density of 0.62 A cm−2 at 0.6 V

  13. Polyaromatic polymers as binders in PEMFC catalyst layers

    Energy Technology Data Exchange (ETDEWEB)

    Peron, J.M.; Edwards, D.; Le Marquand, P.; Shi, Z.; Holdcroft, S. [National Research Council of Canada, Vancouver, BC (Canada). Inst. for Fuel Cell Innovation

    2009-07-01

    The catalyst layers in proton exchange membrane (PEM) fuel cells are typically composed of platinum as the catalyst and carbon as the electron conductor. The binder that ensures the ionic pathway between catalyst particles and the electrolyte membrane is a perfluorinated polymer that brings the electrolyte, gaseous reactants, electrocatalyst and current collector into close contact within a confined spatial region known as the triple-phase-boundary. New non-fluorinated polymers have been developed in an effort to lower the cost and improve the stability of fuel cells. Although polyaromatic polymers have been extensively presented in the literature for membrane preparation, these new materials have been mainly characterized in presence of Nafion as a binder in the catalyst layer. This paper discussed the incorporation of polyaromatic polymers, such as sulfonated-PEEK (sPEEK), and its properties as a binder. sPEEK-based catalyst ink solutions, using different sPEEK/Pt ratios and preparation methods, have been deposited on membranes to form catalyst-coated-membranes (CCM). Initial catalyst ink were characterized using dynamic light scattering to determine agglomerate size. Catalyst layers were examined using SEM and TEM and their porosity was determined by Hg porosimetry. Various electrochemical techniques were used for in-situ characterization of prepared sPEEK CCMs.

  14. Composite plasma polymerized sulfonated polystyrene membrane for PEMFC

    Energy Technology Data Exchange (ETDEWEB)

    Nath, Bhabesh Kumar; Khan, Aziz; Chutia, Joyanti, E-mail: jchutiaiasst@gmail.com

    2015-10-15

    Highlights: • Methyl methane sulfonate (MMS) is used as the sulfonating agent. • The proton conductivity of the membrane is found to be 0.141 S cm{sup −1}. • Power density of fuel cell with styrene/MMS membrane is 0.5 W cm{sup −2}. • The membrane exhibits thermal stability up to 140 °C. - Abstract: This work presents the introduction of an organic compound methyl methane sulfonate (MMS) for the first time in fabrication of polystyrene based proton exchange membrane (PEM) by plasma polymerization process. The membrane is fabricated by co-polymerizing styrene and MMS in capacitively coupled continuous RF plasma. The chemical composition of the plasma polymerized polymer membrane is investigated using Fourier Transform Infrared Spectroscopy which reveals the formation of composite structure of styrene and MMS. The surface morphology studied using AFM and SEM depicts the effect of higher partial pressure of MMS on surface topography of the membrane. The proton transport property of the membrane studied using electrochemical impedance spectroscopy shows the achievement of maximum proton conductivity of 0.141 S cm{sup −1} which is comparable to Nafion 117 membrane. Fuel cell performance test of the synthesized membrane shows a maximum power density of 500 mW cm{sup −2} and current density of 0.62 A cm{sup −2} at 0.6 V.

  15. Effect of a rigid gas diffusion media applied as distributor of reagents in a PEMFC in operation, part 1 : dry gases

    Energy Technology Data Exchange (ETDEWEB)

    Bautista-Rodriquez, C.M.; Rosas-Paleta, M.G.A.; Tapia-Pachuca, A.B. [Alter Energias Group, Puebla (Mexico); Rivera-Marquez, J.A. [Benemerita Univ. Autonoma de Puebla, Puebla (Mexico). Faculty of Chemical Engineering; Garcia de la Vega, J.R. [Uhde Engineering de Mexico, Mexico City (Mexico)

    2010-07-15

    During the operation of a proton exchange membrane fuel cell (PEMFC), several mass transport phenomena develop, generating a mechanical-physics resistance to some extent, implying limitations during operation. In a conventional fuel cell, the feeding reactive gases to the sites of reaction are performed by a series of elements, such as channels in the polar plates, diffusion layer on the electrodes and the active layer where it realizes the electrochemical semi reaction. Previous studies have reported and demonstrated the generation of gradients of concentration in reagents between the channels of distribution and diffusion layer, representing a limiting in the transport of reagents to the active sites as well as resistance to the mass transport of reagents as a result of the presence of water product in the pores of electrodes. This paper focused on lowering the resistance to mass transport by applying a rigid gas diffusion media with many macropores as distributor of reagents. The objective was to encourage the mass transport phenomena to the active sites on the electrodes. This paper described the experiment and presented the results of the study. The experiment involved the application of a rigid gas diffusion media as a reagents distributor with a serpentine channel distributor, both manufactured with mixes of carbon and graphite powder. The study showed that in general, the GDMR became a diffusion layer, integrating a composite electrode with the graphitized paper and catalyst coated membrane assembly. Under conditions of variable cathodic pressure, the response of the GDMR became a combined distribution plate (conductive and diffusion mass transport), favouring the increase in current density and power developed by the PEMFC in pressure function. 33 refs., 2 tabs., 14 figs.

  16. Graphitised Carbon Nanofibres as Catalyst Support for PEMFC

    DEFF Research Database (Denmark)

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

    2011-01-01

    catalyst and the effects of the different surface treatments were discussed. On the basis of these results, new membrane electrode assemblies (MEAs) were manufactured and tested also for carbon corrosion by in situ FTIR analysis of the cathode exhaust gases. It was observed that the G-CNFs showed 5?times......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 for the...... anchorage of Pt catalyst nanoparticles. Modification of the fibre surface is therefore needed. In this study Pt nanoparticles have been deposited onto as-received and surface-modified G-CNFs. The surface modifications of the fibres comprise acid treatment and nitrogen doping by pyrolysis of a polyaniline...

  17. 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...... a significant role in the performance of the final electrode product. In this work, ex situ study of Nafion ionomer isothermal adsorption on catalysts / support materials is carried out. Experimental technique and method are improved based on earlier experience. Observation of Nafion ionomer in...

  18. Electrospun nanofibre composite polymer electrolyte fuel cell and electrolysis membranes

    OpenAIRE

    Sood, Rakhi; Cavaliere, Sara; Rozière, Jacques; Jones, Deborah

    2016-01-01

    International audience Large-scale commercialisation of Proton Exchange Membrane Fuel Cell (PEMFC) technology for automotive and stationary applications demands the development of a robust, durable and cost-effective materials. In this regard, ionomer membranes being present at the core of PEMFCs are required to maintain elevated proton conductivity, high mechanical strength and low gas permeability during the lifespan of the fuel cell. These challenges are addressed by investigating novel...

  19. 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)

  20. 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)

  1. Numerical Investigation of the Water Droplet Transport in a PEM Fuel Cell with Serpentine Flow Channel

    OpenAIRE

    Bittagopal Mondal; Dipankar Chatterjee

    2016-01-01

    The serpentine flow channel can be considered as one of the most common and practical channel layouts for a polymer electrolyte membrane fuel cell (PEMFC) since it ensures an effective and efficient removal of water produced in a cell with acceptable parasitic load. Water management is one of the key issues to improve the cell performance since at low operating temperatures in PEMFC, water vapor condensation starts easily and accumulates the liquid water droplet within the flow channels, thus...

  2. PEMFC cold-start performance after twice purge%二次吹扫条件下的PEMFC冷启动实验

    Institute of Scientific and Technical Information of China (English)

    罗马吉; 王芳芳; 刘威; 詹志刚

    2011-01-01

    通过使用干空气二次吹扫的方式对稳定工作后的质子交换膜燃料电池(PEMFC)单电池进行除水处理,考察了单电池经过吹扫除水操作后的除水量以及内阻变化过程,并研究了单电池经过吹扫除水处理后的常温启动性能以及-10℃下的冷启动性能.实验研究发现:单电池经过干空气二次吹扫处理后,可以在较短时间内经济有效地移除电池内的水,同时单电池的内阻升高.单电池经过干空气二次吹扫后常温启动性能下降,且随二次吹扫流量的增加而加剧,但未造成不可恢复的性能损失.适当的二次吹扫流量可以使电池成功冷启动.吹扫除水策略是优化PEMFC冷启动性能的关键因素之一.%Water in an operated proton exchange membrane fuel cell (PEMFC) was removed by twice purging with dry air. The weight of removed water and the process of resistance-change were investigated after the gas purging operation on the cell. The start-up performance of the cell in normal temperature and the cold start-up performance at -10 °C after purge were studied. The experimental results indicate that the water in a single cell can be removed in quite short time effectively and the cell electric resistance increase after twice purging. The start-up performance of the cells in normal temperature become deteriorated and get worse with the increased purging gas volume after twice purging, but the performance degradation can be recovered. Cold start-up of single cell can perform successfully by appropriate flow rate of twice purging. Purge strategy is one of the key points of optimizing fuel cell cold start-up performance.

  3. 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.

  4. 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)

  5. New hybrid model of proton exchange membrane fuel cell

    Institute of Scientific and Technical Information of China (English)

    WANG Rui-min; CAO Guang-yi; ZHU Xin-jian

    2007-01-01

    Model and simulation are good tools for design optimization of fuel cell systems. This paper proposes a new hybrid model of proton exchange membrane fuel cell (PEMFC). The hybrid model includes physical component and black-box component. The physical component represents the well-known part of PEMFC, while artificial neural network (ANN) component estimates the poorly known part of PEMFC. The ANN model can compensate the performance of the physical model. This hybrid model is implemented on Matlab/Simulink software. The hybrid model shows better accuracy than that of the physical model and ANN model. Simulation results suggest that the hybrid model can be used as a suitable and accurate model for PEMFC.

  6. 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

  7. Transient carbon monoxide poisoning kinetics during warm-up period of a high-temperature PEMFC – Physical model and parametric study

    International Nuclear Information System (INIS)

    Highlights: • The extracted current density and CO volume fraction should be reduced to avoid sudden shoot up of the anode overpotential. • The temperature increase rate and the initial start-up temperature should be increased to avoid sudden shoot up of the anode overpotential. • An initial start-up temperature of 130 ± 5 °C is recommended to avoid premature shut down of the fuel cell. - Abstract: This paper investigates the anode electrokinetics during the start-up or warm-up period of a high-temperature proton exchange membrane fuel cell (HT-PEMFC) from a temperature above 100 °C, to the desired temperature of 180 °C, where carbon monoxide (CO) contaminated hydrogen (H2) is used as the fuel. The heating strategy considered in this study involves an initial heating of the HT-PEMFC by an external source to a temperature above 100 °C, after which current is drawn, where electrochemical reaction heating is expected to contribute to the heating process. Thus, a numerical transient three-dimensional model is derived addressing the anode electrokinetics under a specific temperature increase rate during the warm-up process. Operational parameters such as temperature increase rate, initial start-up temperature, CO volume fraction and extracted current density are varied and their effects on the CO and hydrogen coverage fractions on the electrode, the anode overpotential and the cell potential with respect to time, are studied. The results indicate that parameters such as temperature increase rate, initial start-up temperature, CO volume fraction and extracted current density would significantly affect the anode overpotential and the cell potential. Specifically, it is critical to reduce the extracted current density and CO volume fraction, and increase the temperature increase rate, to avoid a sudden shoot up of the anode overpotential that can result in the premature shutdown of the fuel cell. Having a low initial start-up temperature does result in a higher

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

    International Nuclear Information System (INIS)

    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.

  9. Durability Issues of High Temperature Proton Exchange Membrane Fuel Cells Based on Acid Doped Polybenzimidazole Membranes

    DEFF Research Database (Denmark)

    To achieve high temperature operation of proton exchange membrane fuel cells (PEMFC), preferably under ambient pressure, phosphoric acid doped polybenzimidazole (PBI) membrane represents an effective approach, which in recent years has motivated extensive research activities with great progress. As...

  10. 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.

  11. 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.

  12. 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)

  13. Study of PEMFC ionomers through model molecules mimicking the ionomer repeat units

    Energy Technology Data Exchange (ETDEWEB)

    Marechal, Manuel; Wessel, Rudolf; Diard, Jean Paul; Guindet, Jacques; Sanchez, Jean-Yves [Ecole Nationale Superieure d' Electrochimie et d' Electrometallurgie de Grenoble, Laboratoire d' Electrochimie et de Physico-chimie des Materiaux et des Interfaces, UMR 5631 CNRS-INPG-UJF, Domaine Universitaire, BP 75, 38402 Saint Martin d' Heres (France)

    2007-11-01

    The thermal and electrochemical behaviours of PEMFC ionomers based on an aromatic backbone i.e., sulfonated polysulfones, sulfonated polyetheretherketones and sulfonated polybenzimidazoles, were investigated through their model molecules. Thermal degradation was characterized by weight losses and allowed inferring ionomer thermal degradations by chain breakings that cannot be detected by thermogravimetric analysis. In addition, cyclic voltammetry was used to characterize the electroactivity of some ionomers, related to their backbone and their ionic moieties. The use of model molecules is thus a useful tool for assessing both the thermal and electrochemical stability of ionomers. Lastly, due to the high concentrations used in liquid electrolytes as compared with an electrode/membrane interface it may be considered as an electrochemical aging test. (author)

  14. 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

  15. CO detection in H2 reducing atmosphere with mini fuel cell

    OpenAIRE

    Pijolat, Christophe; Tournier, Guy; Viricelle, Jean-Paul

    2011-01-01

    International audience A prototype of a miniaturized fuel cell has been studied in order to detect carbon monoxide in hydrogen-rich atmosphere for PEMFC (proton exchange membrane fuel cell) applications. It consists on a single PEMFC (membrane-electrode-assembly supplied by CEA/LITEN) directly fed by the hydrogen-carbon monoxide mixture while the cathode is exposed to ambient air. Experiments have been carried out on a laboratory testing bench with simulated reforming gas. Two working mode...

  16. APACHE: Integrated Hybrid Fuel Cell System for 2-Seat All Electric Aircraft Propulsion

    OpenAIRE

    Hordé, Théophile; Achard, Patrick; Metkemeijer, Rudolf

    2012-01-01

    International audience The French APACHE project aims at demonstrating the feasibility of using a Hybrid Fuel Cell System (HFCS) as the power generator for all electric 2-seat aircrafts. This study focuses on three main topics: airworthiness of Proton Exchange Membrane Fuel Cells (PEMFC), their hybridization with Lithium Ion (Li-Ion) batteries and systems' integration into light aircrafts. Altitude and inclination tests have been led and allow to conclude on the ability of PEMFC to operate...

  17. Sobre a natureza multidimensional do desenvolvimento

    OpenAIRE

    Moreira, Sandrina Berthault

    2009-01-01

    Comunicação apresentada no X Congresso Luso-Afro-Brasileiro de Ciências Sociais: Sociedades Desiguais e Paradigmas em Confronto - 2009, Braga Desde muito cedo se observam esforços na pesquisa de novos conceitos de desenvolvimento que se afastassem da sua identificação com o crescimento económico saída do pós-guerra. Os contributos críticos e de busca de um novo conceito de desenvolvimento surgem, especialmente, a partir da década de 70, vindo a estabilizar nos conceitos de desenvolvi...

  18. Evaluation of an integrated methane autothermal reforming and high-temperature proton exchange membrane fuel cell system

    International Nuclear Information System (INIS)

    The aim of this study was to investigate the performance and efficiency of an integrated autothermal reforming and HT-PEMFC (high-temperature proton exchange membrane fuel cell) system fueled by methane. Effect of the inclusion of a CO (carbon monoxide) removal process on the integrated HT-PEMFC system was considered. An increase in the S/C (steam-to-carbon) ratio and the reformer temperature can enhance the hydrogen fraction while the CO formation reduces with increasing S/C ratio. The fuel processor efficiency of the methane autothermal reformer with a WGS (water gas shift reactor) reactor, as the CO removal process, is higher than that without a WGS reactor. A higher fuel processor efficiency can be obtained when the feed of the autothermal reformer is preheated to the reformer temperature. Regarding the cell performance, the reformate gas from the methane reformer operated at Tin = TR and with a high S/C ratio is suitable for the HT-PEMFC system without a WGS reactor. When considering the HT-PEMFC system with a WGS reactor, the CO poisoning has less significant impact on the cell performance and the system can be operated over a broader range to minimize the required total active area. A WGS reactor is necessary for the methane autothermal reforming and HT-PEMFC integrated system with regard to the system efficiency. - Highlights: • An integrated autothermal reforming and HT-PEMFC system was studied. • The HT-PEMFC system with and without a CO removal process was considered. • Parametric analysis was performed to obtain a high system efficiency. • The HT-PEMFC system with the WGS reactor can be run over a broader range. • The efficiencies of the HT-PEMFC systems without and with a WGS reactor were reported

  19. 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

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

    DEFF Research Database (Denmark)

    Jensen, Jens Oluf; Li, Qingfeng

    Polymer electrolyte membrane fuel cell (PEMFC) technology based on Nafion membranes can operate at temperatures around 80°C. The new development in the field is high temperature PEMFC for operation above 100°C, which has been successfully demonstrated through the previous EC Joule III and the 5th...... system integration of the high temperature PEMFC. The strategic developments of the FURIM are in three steps: (1) further improvement of the high temperature polymer membranes and related materials; (2) development of technological units including fuel cell stack, hydrocarbon reformer, afterburner and......, 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...

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

    Directory of Open Access Journals (Sweden)

    Dimitrios C. Papageorgopoulos

    2012-12-01

    Full Text Available 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.

  2. 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

  3. An energetic-exergetic analysis of a residential CHP system based on PEM fuel cell

    International Nuclear Information System (INIS)

    Highlights: → A zero-dimensional of a micro cogenerative (CHP) energy system based on a Proton Exchange Membrane fuel cell (PEMFC) has been developed. → The electrochemical model has been validated with experimental data. → The performances of this CHP system have been evaluated through a series of simulations. → An energy/exergy analysis of the simulation results has allowed to define the PEMFC optimal operating conditions. → The PEMFC optimal operating conditions detected are: 1 atm, 353.15 K and 100% RH. -- Abstract: The use of fuel cell systems for distributed residential power generation represents an interesting alternative to traditional thermoelectric plants due to their high efficiency and the potential recovering of the heat generated by the internal electrochemical reactions. In this paper the study of a micro cogenerative (CHP) energy system based on a Proton Exchange Membrane fuel cell (PEMFC) is reported. With the aim to evaluate the performance and then the feasibility of this non-conventional energy system, in consideration of thermal and electrical basic demand of a multifamily apartment blocks, a zero-dimensional PEMFC model in Aspen Plus environment has been developed. A simulations sequence has been carried out at different operating conditions of the fuel cell (varying temperature, pressure and relative humidity). Subsequently, on the basis of the obtained results, an energy/exergy analysis has been conducted to define the optimal operating conditions of the PEMFC that ensures the most efficient use of the energy and exergy inputs.

  4. Proton Exchange Membrane Fuel Cell Modeling Based on Seeker Optimization Algorithm

    Institute of Scientific and Technical Information of China (English)

    LI Qi; DAI Chao-hua; Chen Wei-rong; JIA Jun-bo; HAN Ming

    2008-01-01

    Seeker optimization algorithm (SOA) has applications in continuous space of swarm intelligence. In the fields of proton ex-change membrane fuel cell (PEMFC) modeling, SOA was proposed to research a set of optimized parameters in PEMFC polariza-tion curve model. Experimental result showed that the mean square error of the optimization modeling strategy was only 6.9 × 10-23. Hence, the optimization model could fit the experiment data with high precision.

  5. Extended Two Dimensional Nanotube and Nanowire Surfaces as Fuel Cell Catalysts

    OpenAIRE

    Alia, Shaun Michael

    2011-01-01

    Extended network nanomaterials of platinum (Pt), silver (Ag), palladium (Pd), and gold (Au) are synthesized and characterized as proton exchange membrane (PEMFC), hydroxide exchange membrane (HEMFC), and direct alcohol (DAFC) fuel cell catalysts.Porous Pt nanotubes (PPtNTs), 5 nm thick, are synthesized by the galvanic displacement of Ag nanowires (AgNWs) for PEMFCs and DAFCs. PPtNTs produce oxygen reduction (ORR) and durability characteristics significantly higher than supported Pt nanopartic...

  6. 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.)

  7. Effect of annealing on two different niobium-clad stainless steel PEMFC bipolar plate materials

    Institute of Scientific and Technical Information of China (English)

    Sung-Tae HONG; Dae-Wook KIM; Yong-Joo YOU; K.Scott WEIL

    2009-01-01

    Niobium (Nb)-clad stainless steels(SS) produced via roll bonding are being considered for use in the bipolar plates of polymer electrolyte membrane fuel celI(PEMFC) stacks. Because the roll bonding process induces substantial work hardening in the constituent materials, thermal annealing is used to restore ductility to the clad sheet so that it can be subsequently blanked, stamped and dimpled in forming the final plate component. Two roll bonded materials, niobium clad 340L stainless steel (Nb/340L SS) and niobium clad 434 stainless steel (Nb/434 SS) were annealed under optimized conditions prescribed by the cladding manufacturer. Comparative mechanical testing conducted on each material before and after annealing shows significant improvement in ductility in both cases. However, corresponding microstructural analyses indicate an obvious difference between the two heat treated materials. During annealing, an interlayer with thick less than 1 μm forms between the constituent layers in the Nb/340L SS, whereas no interlayer is found in the annealed Nb/434 SS material. Prior work suggests that internal defects potentially can be generated in such an interlayer during metal forming operations. Thus, Nb/434 SS may be the preferred candidate material for this application.

  8. Investigation of high temperature operation of proton exchange membrane fuel cells

    Science.gov (United States)

    Adjemian, Kevork Tro

    Proton exchange membrane fuel cells (PEMFCs) have garnered much attention in the media over the past years as they can provide a clean, environmentally friendly alternative to internal combustion engines. PEMFCs also have the flexibility to operate on many different types of fuels, thereby diminishing our reliance on foreign oil. PEMFCs, however, suffer from many drawbacks which need to be overcome before mass production becomes viable. One drawback is the expense of the fuel cell system, costing several times more than existing technologies. Another problem is that if the fuel cell is running on reformed fuels, trace amounts of carbon monoxide (10 ppm) in the hydrogen gas stream will completely poison the anode electrocatalyst, killing the PEMFC. Also, as a lot of waste heat is generated, a very elaborate cooling system needs to be used, making the overall system more expensive and complex. A possible solution to both the carbon monoxide poisoning and thermal management of a PEMFC is to elevate its operating temperature above 100°C. Unfortunately, current state-of-the-art electrolytes used in PEMFCs, i.e. Nafion 115, rely on water for the conduction of protons and by elevating the temperature, water loss occurs due to evaporation resulting in inadequate PEMFC performance. This thesis delves into the modification of Nafion and similar electrolytes to permit PEMFC operation above 100°C. This was accomplished by impregnating the pores of the Nafion with hydrophilic inorganic materials-silicon oxide via sol-gel processing and various inorganic particles. By performing these modifications to the various electrolytes, several composite membranes performed exceptionally well at an operating temperature of 130°C and demonstrated carbon monoxide tolerance of up to 500 ppm. In addition, a theory on how these materials help improve the water management characteristics of Nafion was developed, laying the foundation for the development of a completely novel membrane to

  9. Estimation of equivalent internal-resistance of PEM fuel cell using artificial neural networks

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    A practical method of estimation for the internal-resistance of polymer electrolyte membrane fuel cell (PEMFC) stack was adopted based on radial basis function (RBF) neural networks. In the training process, k-means clustering algorithm was applied to select the network centers of the input training data. Furthermore, an equivalent electrical-circuit model with this internal-resistance was developed for investigation on the stack. Finally using the neural networks model of the equivalent resistance in the PEMFC stack, the simulation results of the estimation of equivalent internal-resistance of PEMFC were presented. The results show that this electrical PEMFC model is effective and is suitable for the study of control scheme, fault detection and the engineering analysis of electrical circuits.

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

    International Nuclear Information System (INIS)

    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)

  11. High-performance Fuel Cell with Stretched Catalyst-Coated Membrane: One-step Formation of Cracked Electrode

    OpenAIRE

    Sang Moon Kim; Chi-Yeong Ahn; Yong-Hun Cho; Sungjun Kim; Wonchan Hwang; Segeun Jang; Sungsoo Shin; Gunhee Lee; Yung-Eun Sung; Mansoo Choi

    2016-01-01

    We have achieved performance enhancement of polymer electrolyte membrane fuel cell (PEMFC) though crack generation on its electrodes. It is the first attempt to enhance the performance of PEMFC by using cracks which are generally considered as defects. The pre-defined, cracked electrode was generated by stretching a catalyst-coated Nafion membrane. With the strain-stress property of the membrane that is unique in the aspect of plastic deformation, membrane electrolyte assembly (MEA) was succe...

  12. 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

  13. 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...... been investigated. The fuel cell stack used in this model is developed using a Ballard PEMFC [1], so that the equations used in the stack modeling are derived from the experimental data. The stack can produce 3 to 15 kilowatt electricity depending on the number of cells used in the stack. Some of the...... investigated. In addition, different stack design schemes have been proposed and their effect on system efficiency has been investigated....

  14. New electrocatalyst support for high temperature PEM fuel cells (HT-PEMFC)

    Energy Technology Data Exchange (ETDEWEB)

    Boaventura, M.; Brandao, L.; Mendes, A. [Porto Univ. (PT). Lab. de Engenharia de Processos, Ambiente e Energia (LEPAE)

    2010-07-01

    This work compares the performance of electrocatalysts based on platinum supported in single-wall carbon nanohorns (Pt-SWNH) and supported in carbon black (Pt-carbon black) during high temperature PEM fuel operation. MEAs made of phosphoric acid doped polybenzimidazole (PBI/H{sub 3}PO{sub 4}) were characterized by polarization curves, electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV), at 160 C. The Pt-SWNH electrocatalyst presented a higher electrochemical surface area (ESA) when compared to Pt-carbon black. However, electrochemical experiments showed a higher ohmic resistance of the Pt-SWNH electrode related to a higher hydrophobic character of the SWNH carbon. (orig.)

  15. 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

  16. Experimental Approach for Water Discharge Characteristics at PEMFC by using Neutron Imaging Technique considered Neutron Flux and Linear Attenuation Coefficient of Thermal Neutron Correction at NRF, HANARO

    International Nuclear Information System (INIS)

    The neutron imaging technique was used to investigate the water discharge characteristics at PEMFC. Prior to investigation of water discharge characteristics, the linear attenuation coefficient for water at Neutron Radiography Facility (NRF) was calibrated. The feasibility test apparatus was consisted of pressurized air and water in order to simulate the actual operating PEMFC. The feasibility tests have been performed at 1-parallel serpentine type with 100 cm2 active area and different air flow rate (1, 2, and 4 lpm). The total water volume variations at each condition were calculated from the neutron images. The water at channel is well discharged as soon as supplying the pressurized air into the PEMFC. However, because the water at MEA isn't removed the total water volume is constant after 150. Therefore more effective method is needed in order to discharge water at MEA, and the neutron imaging technique is helpful for it

  17. Direct observation of the dealloying process of a platinum–yttrium nanoparticle fuel cell cathode and its oxygenated species during the oxygen reduction reaction

    OpenAIRE

    Kaya, Sarp; Malacrida, Paolo; Casalongue, Hernan G. Sanchez; Masini, Federico; Hernandez-Fernandez, Patricia; Deiana, Davide; Ogasawara, Hirohito; Stephens, Ifan E. L.; Nilsson, Anders; Chorkendorff, Ib

    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 understanding of both their activity and stability. Herein, size-selected 9 nm PtxY nanoparticles have been deposited on the cathode side of a PEMFC specifically designed for in situ ambient pressure X-...

  18. 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...

  19. Renewable energies - Fuel cell and hydrogen

    International Nuclear Information System (INIS)

    The objectives of the IPEN program are based on the MCT (Brazilian Ministry of Science and Technology) national program, contributing significantly to the national development in this area. The program comprises three main areas of interest: PEMFC (Proton Exchange Membrane Fuel Cell); SOFC(Solid Oxide Fuel Cell); and H2-Production, mainly from ethanol reforming

  20. Synthesis methods of low-Pt-loading electrocatalysts for proton exchange membrane fuel cell systems

    International Nuclear Information System (INIS)

    While the use of a high level of platinum (Pt) loading in proton exchange membrane fuel cells (PEMFCs) can amplify the trade off towards higher performance and longer lifespan for these PEMFCs, the development of PEMFC electrocatalysts with low-Pt-loadings and high-Pt-utilization is critical and the limited supply and high cost of the Pt used in PEMFC electrocatalysts necessitate a reduction in the Pt level. In order to make such electrocatalysts commercially feasible, cost-effective and innovative, catalyst synthesis methods are needed for Pt loading reduction and performance optimization. Since a Pt-deposited carbon nanotube (CNT) shows higher performance than a commercial Pt-deposited carbon black (CB) with reducing 60% Pt load per electrode area in PEMFCs, use of CNTs in preparing electrocatalysts becomes considerable. This paper reviews the literature on the synthesis methods of carbon-supported Pt electrocatalysts for PEMFC catalyst loading reduction through the improvement of catalyst utilization and activity. The features of electroless deposition (ED) method, deposition on sonochemically treated CNTs, polyol process, electrodeposition method, sputter-deposition technique, γ-irradiation method, microemulsion method, aerosol assisted deposition (AAD) method, Pechini method, supercritical deposition technique, hydrothermal method and colloid method are discussed and characteristics of each one are considered.

  1. Synthesis methods of low-Pt-loading electrocatalysts for proton exchange membrane fuel cell systems

    Energy Technology Data Exchange (ETDEWEB)

    Esmaeilifar, A.; Ghazanfari, E. [Fuel Cell Laboratory, Green Research Center, Iran University of Science and Technology, Tehran (Iran); Rowshanzamir, S. [Fuel Cell Laboratory, Green Research Center, Iran University of Science and Technology, Tehran (Iran); School of Chemical Engineering, Iran University of Science and Technology, Narmak, Tehran 16846-13114 (Iran); Eikani, M.H. [Department of Chemical Industries, Iranian Research Organization for Science and Technology (IROST), Tehran (Iran)

    2010-09-15

    While the use of a high level of platinum (Pt) loading in proton exchange membrane fuel cells (PEMFCs) can amplify the trade off towards higher performance and longer lifespan for these PEMFCs, the development of PEMFC electrocatalysts with low-Pt-loadings and high-Pt-utilization is critical and the limited supply and high cost of the Pt used in PEMFC electrocatalysts necessitate a reduction in the Pt level. In order to make such electrocatalysts commercially feasible, cost-effective and innovative, catalyst synthesis methods are needed for Pt loading reduction and performance optimization. Since a Pt-deposited carbon nanotube (CNT) shows higher performance than a commercial Pt-deposited carbon black (CB) with reducing 60% Pt load per electrode area in PEMFCs, use of CNTs in preparing electrocatalysts becomes considerable. This paper reviews the literature on the synthesis methods of carbon-supported Pt electrocatalysts for PEMFC catalyst loading reduction through the improvement of catalyst utilization and activity. The features of electroless deposition (ED) method, deposition on sonochemically treated CNTs, polyol process, electrodeposition method, sputter-deposition technique, {gamma}-irradiation method, microemulsion method, aerosol assisted deposition (AAD) method, Pechini method, supercritical deposition technique, hydrothermal method and colloid method are discussed and characteristics of each one are considered. (author)

  2. 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...

  3. CAPITAL SOCIAL COMO FATOR DE DESENVOLVIMENTO LOCAL

    OpenAIRE

    Mendonca, Kamila Vieira; Pinheiro, Jose Cesar

    2008-01-01

    O presente estudo verificou e avaliou o grau de acumulação de capital social como fator de desenvolvimento local, do assentamento Che Guevara, localizado no município de Ocara, no Estado do Ceará. O índice de capital social (ICS) foi calculado com base nas respostas de um questionário elaborado com variáveis mensuráveis e que refletem o estoque de capital social. A comunidade dispõe de um grau mediano de capital social.-------------This study verified and evaluated the degree of accumulation ...

  4. DESENVOLVIMENTO MORAL E INDISCIPLINA NA ESCOLA

    Directory of Open Access Journals (Sweden)

    Rita Melissa Lepre

    2009-12-01

    Full Text Available O presente artigo configura-se como uma reflexão acerca da indisciplina e suas possíveis causas. Para debater sobre o assunto apresentamos a teoria do desenvolvimento moral de Jean Piaget e articulamos suas descobertas com a questão da indisciplina na escola. São feitas, ainda, reflexões sobre o ambiente em que nossas crianças encontram-se inseridas por, pelo menos, cinco horas diárias.

  5. Gênese e desenvolvimento do conceito de vida

    OpenAIRE

    Bertoni, Danislei

    2013-01-01

    Resumo: O objeto dessa tese é a defesa em torno da possibilidade em delinear o processo histórico de gênese e desenvolvimento do conceito vida. A construção das ideias permite a compreensão de como surgiu o atual conceito de vida e uma das possibilidades se baseia na emergência das concepções de vida que historicamente foram elaboradas e coexistiram no modo de interpretar esse fenômeno. Para compreender a emergência dessas concepções foi necessário estabelecer os estilos de pensamento biológi...

  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. Maximum power efficiency operation and generalized predictive control of PEM (proton exchange membrane) fuel cell

    International Nuclear Information System (INIS)

    Operating a proton exchange membrane fuel cell (PEMFC) system to produce power at the maximum power efficiency is one of the key issues in PEMFC's wide-spread applications. However, power density exhibits complex behavior and nonlinear dynamics with respect to the output cell voltage, fuel cell temperature, anode and cathode pressure, inlet gas humidity, and so on. In this paper, the distribution of power density in the domain of the output cell voltage and fuel cell temperature is delineated. By this delineation, the quadratic polynomial fitting was used to approximate the power density curve in local interval and estimate the maximum power efficiency point. Generalized predictive control (GPC) is presented to overcome the problem of time-varying dynamics of PEMFC in real time via applying a forgetting factor recursive least square (FFRLS) method. Based on the approximation and generalized predictive control strategy, maximum power efficiency operation of PEMFC is applied. The results of this work can contribute to the operation of PEMFC at the maximum power point, which guarantees the plant generating maximum power at the lowest consumption of hydrogen. - Highlights: • Operating the PEMFC at the maximum power efficiency point is achieved with the lowest consumption of hydrogen. • The quadratic polynomial fitting method is used to estimate the maximum power efficiency point in local interval. • A data-driven predictive model is introduced to overcome the time-varying dynamics of PEMFC in real time. • Generalized predictive control (GPC) strategy is designed to optimize flow rates of hydrogen and coolant on-line

  8. Efeito do número da passagem e do gênero das células doadoras de núcleo no desenvolvimento de bovinos produzidos por transferência nuclear Effect of culture time and gender of nuclei donor cells on bovine development produced by nuclear transfer

    Directory of Open Access Journals (Sweden)

    Giovana Krempel Fonseca Merighe

    2010-10-01

    Full Text Available Objetivou-se com este trabalho avaliar o efeito do número da passagem e do sexo das células doadoras de núcleo no desenvolvimento embrionário e fetal após transferência nuclear. Para isso, oócitos bovinos foram maturados, enucleados e reconstruídos com células somáticas de animal adulto. Após a fusão e ativação química, os zigotos reconstituídos foram cultivados em Charles Rosenkranz 2 (CR2 com monocamada de células da granulosa a 38,8ºC em atmosfera umidificada a 5% de CO2 em ar, durante sete dias, e transferidos para receptoras sincronizadas. As taxas de clivagem e desenvolvimento a blastocisto de embriões reconstruídos com células cultivadas por tempo maior foram inferiores às obtidas com os demais tempos de cultivo. Além disso, os blastocistos produzidos não resultaram no desenvolvimento de uma gestação a termo. Embora a taxa de clivagem em embriões fêmeas tenha sido maior, o número de embriões que atingiram o estádio de blastocisto foi maior nos embriões machos. No período gestacional, fêmeas apresentaram maior taxa de aborto entre 90 e 120 dias de gestação. Esses resultados indicam que células doadoras de núcleos cultivados por longos períodos dificultam a produção de blastocistos e aumentam as chances de perdas durante a gestação. Embriões clonados machos têm maior competência para se desenvolver a blastocisto e resultam em menor taxa de perda gestacional.The objective of this study was to evaluate the effects of culture time and sex of nuclei donor cells on embryo and fetal development after nuclear transfer. Thus, bovine oocytes were matured, enucleated and reconstructed with somatic cells from an adult animal. After fusion and chemical activation, the reconstituted zygotes were cultured in Charles Rosenkranz 2 (CR2 on a granular monolayer cell at 38.8ºC in a humidified atmosphere 5% CO2 in air for seven days, and transferred to synchronized receptors. Cleavage rates and development to

  9. 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.

  10. 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.

  11. Desenvolvimento regional: a diversidade regional como potencialidade

    Directory of Open Access Journals (Sweden)

    Virginia Elisabeta Etges

    2013-03-01

    Full Text Available Ao longo da segunda metade do século XX o debate sobre desenvolvimento regional no Brasil recebeu atenção especial, principalmente, entre economistas e geógrafos. Dois enfoques principais se destacam no debate: um, que entende a promoção do desenvolvimento regional a partir da redução/eliminação das desigualdades regionais; outro, que propõe a compreensão da diversidade regional como potencialidade para o desenvolvimento de regiões. O primeiro foi e continua sendo hegemônico, evidenciado tanto em trabalhos científicos quanto em documentos norteadores das políticas públicas na área. Já o segundo evidencia-se mais claramente a partir da década de 1990, período em que o conceito de região é retomado sob um novo enfoque. Neste trabalho pretende-se explicitar o significado de cada uma dessas concepções, no intuito de contribuir para a qualificação da discussão sobre desenvolvimento regional.Palavras-chave | Desenvolvimento regional; diversidade regional; potencialidades; região.Código JEL | O18; R11; R58. REGIONAL DEVELOPMENT: REGIONAL DIVERSITY AS POTENTIALAbstractThroughout the second half of the twentieth century the debate on regional development in Brazil received special attention, especially among economists and geographers. Two main approaches stand out in the debate: one that understands the promotion of regional development from the reduction / elimination of regional inequalities, and the other proposes the understanding of regional diversity and potentiality for developing regions. The first was and still remains hegemonic, being evidenced both in scientific papers and in documents guiding public policies in the area. The latter is evidenced most clearly from the 1990s on, a period when the concept of region is resumed under a new approach. This paper aims to clarify the meaning of each of these concepts in order to contribute to the qualification of the discussion on regional development.Keywords | Regional

  12. Numerical study of a novel micro-diaphragm flow channel with piezoelectric device for proton exchange membrane fuel cells

    Science.gov (United States)

    Ma, H. K.; Huang, S. H.; Chen, B. R.; Cheng, L. W.

    Previous studies have shown that the amplitude of the vibration of a piezoelectric (PZT) device produces an oscillating flow that changes the chamber volume along with a curvature variation of the diaphragm. In this study, an actuating micro-diaphragm with piezoelectric effects is utilized as an air-flow channel in proton exchange membrane fuel cell (PEMFC) systems, called PZT-PEMFC. This newly designed gas pump, with a piezoelectric actuation structure, can feed air into the system of an air-breathing PEMFC. When the actuator moves outward to increase the cathode channel volume, the air is sucked into the chamber; moving inward decreases the channel's volume and thereby compresses air into the catalyst layer and enhancing the chemical reaction. The air-standard PZT-PEMFC cycle is proposed to describe an air-breathing PZT-PEMFC. A novel design for PZT-PEMFCs has been proposed and a three-dimensional, transitional model has been successfully built to account for its major phenomena and performance. Moreover, at high frequencies, PZT actuation leads to a more stable current output, more drained water, higher sucked air, higher hydrogen consumption, and also overcomes concentration losses.

  13. Do desenvolvimento regional ao desenvolvimento local. Análise de alguns aspectos de política económica regional

    OpenAIRE

    Cabugueira, Artur Carlos Crespo Martins

    2000-01-01

    Neste artigo dedicamos a nossa atenção à problemática do desenvolvimento, não numa perspectiva conceptual, mas sim ao desenvolvimento considerado no espaço real. Quer dizer, abordamos alguns aspectos relacionados com a regionalização do processo de desenvolvimento, ou seja, analisamos alguns aspectos do desenvolvimento regional e local. Partimos do estudo de alguns conceitos básicos do Desenvolvimento Regional, chegando ao estudo do desenvolvimento a nível de unidades territoriais mais res...

  14. Ensaios em instituições e desenvolvimento

    OpenAIRE

    Costantini, Jaime Jordan

    2013-01-01

    Resumo: Esta tese se divide em três ensaios, os quais investigam: (a) As relações que existem entre democracia e desenvolvimento econômico na base do pensamento de Roberto Campos; (b) Os efeitos da instabilidade política no nível do investimento; e (c) Como a volatilidade e tendência dos termos de troca influenciam na acumulação de capital humano em um país em desenvolvimento que exporta matérias primas. De acordo com o pensamento de R. Campos, um país em desenvolvimento como o Brasil deve ac...

  15. Desenvolvimento amazônico em questão

    OpenAIRE

    Luis E. Aragón

    2015-01-01

    Este artigo questiona diferentes aspectos das políticas de desenvolvimento em curso na Amazônia. O argumento central é que o conhecimento da região é condição essencial para alcançar o desenvolvimento socialmente includente, ecologicamente sustentável e economicamente sustentado. Apresentam-se treze pontos para incitar o debate: a invenção da Amazônia, as desigualdades regionais, o conhecimento como fator de desenvolvimento, o investimento em educação, ciência e tecnologia, a fuga de cérebros...

  16. Fault tolerance control for proton exchange membrane fuel cell systems

    Science.gov (United States)

    Wu, Xiaojuan; Zhou, Boyang

    2016-08-01

    Fault diagnosis and controller design are two important aspects to improve proton exchange membrane fuel cell (PEMFC) system durability. However, the two tasks are often separately performed. For example, many pressure and voltage controllers have been successfully built. However, these controllers are designed based on the normal operation of PEMFC. When PEMFC faces problems such as flooding or membrane drying, a controller with a specific design must be used. This paper proposes a unique scheme that simultaneously performs fault diagnosis and tolerance control for the PEMFC system. The proposed control strategy consists of a fault diagnosis, a reconfiguration mechanism and adjustable controllers. Using a back-propagation neural network, a model-based fault detection method is employed to detect the PEMFC current fault type (flooding, membrane drying or normal). According to the diagnosis results, the reconfiguration mechanism determines which backup controllers to be selected. Three nonlinear controllers based on feedback linearization approaches are respectively built to adjust the voltage and pressure difference in the case of normal, membrane drying and flooding conditions. The simulation results illustrate that the proposed fault tolerance control strategy can track the voltage and keep the pressure difference at desired levels in faulty conditions.

  17. Experimental and numerical studies of micro PEM fuel cell

    Institute of Scientific and Technical Information of China (English)

    Rong-Gui Peng; Chen-Chung Chung; Chiun-Hsun Chen

    2011-01-01

    A single micro proton exchange membrane fuel cell (PEMFC) has been produced using Micro-electromechanical systems (MEMS) technology with the active area of 2.5 cm2 and channel depth of about 500μm.A theoretical analysis is performed in this study for a novel MEMS-based design of a micro PEMFC.The model consists of the conservation equations of mass,momentum,species and electric current in a fully integrated finite-volume solver using the CFD-ACE+ commercial code.The polarization curves of simulation are well correlated with experimental data.Three-dimensional simulations are carried out to treat prediction and analysis of micro PEMFC temperature,current density and water distributions in two different fuel flow rates (15 cm3/min and 40 cm3/min).Simulation results show that temperature distribution within the micro PEMFC is affected by water distribution in the membrane and indicate that low and uniform temperature distribution in the membrane at low fuel flow rates leads to increased membrane water distribution and obtains superior micro PEMFC current density distribution under 0.4 V operating voltage.Model predictions are well within those known for experimentalmechanism phenomena.

  18. Tetrazole substituted polymers for high temperature polymer electrolyte fuel cells

    DEFF Research Database (Denmark)

    Henkensmeier, Dirk; My Hanh Duong, Ngoc; Brela, Mateusz;

    2015-01-01

    interesting for use in a high temperature fuel cell (HT PEMFC). Based on these findings, two polymers incorporating the proposed TZ groups were synthesised, formed into membranes, doped with PA and tested for fuel cell relevant properties. At room temperature, TZ-PEEN and commercial meta-PBI showed an...

  19. Apresentação da Linha de Investigação: Desenvolvimento e Risco no Desenvolvimento

    OpenAIRE

    Xavier, Maria Raúl Lobo; Pimentel, Eduarda; Teles, Rita

    2004-01-01

    p. 35-38 A investigação sobre o desenvolvimento, nomeadamente na psicologia do desenvolvimento, preocupa-se hoje com a descrição sistemática e a exploração das mudanças que ocorrem nos indivíduos ao longo do ciclo vital. Com esta amplitude temporal e interesses de pesquisa necessariamente diversificados, os membros desta Linha recorrem a perspectivas e metodologias adequadas que permitem o estudo do desenvolvimento. No entanto, consideramos alguns princípios básicos...

  20. Experimental study of two-phase flow in a proton exchange membrane fuel cell in short-term microgravity condition

    International Nuclear Information System (INIS)

    Highlights: • Two-phase flow in PEMFC cathode channels is observed in different gravity environments. • The PEMFC shows different operating behavior in normal and microgravity conditions. • Water tends can be removed in microgravity conditions at high water production regime. • Liquid aggregation occurs in microgravity conditions at low water production regime. • Effect of gravity on performance and two-phase flow at two operating regimes is studied. - Abstract: Water management is important for improving the performance and stability of proton exchange membrane fuel cells (PEMFCs) for space applications. An in situ visual observation was conducted on the gas–liquid two-phase flow in the cathode channels of a PEMFC in short-term microgravity condition. The microgravity environment was supplied by a drop tower. A single serpentine flow channel with a depth of 2 mm and a width of 2 mm was applied as the cathode flow field. A membrane electrode assembly comprising of a Nafion 112 membrane sandwiched between gas diffusion layers was used. The anode and cathode were loaded with 1 mg cm−2 platinum. The PEMFC shows a distinct operating behavior in microgravity because of the effect of gravity on the two-phase flow. At a high water production regime, cell performance is enhanced by 4.6% and the accumulated liquid water in the flow channel tends can be removed in microgravity conditions to alleviate flooding. At a low water production regime, cell performance deteriorates by 6.6% and liquid aggregation occurs in the flow channel because of the coalescence of dispersed water droplets in microgravity conditions, thus squeezing the flow channel. The operating behavior of PEMFC in microgravity conditions is different from that in normal gravity conditions. Further studies are needed on PEMFC operating characteristics and liquid management for space applications

  1. 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...

  2. 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...

  3. 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...

  4. 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...

  5. Polymer Materials for Fuel Cell Membranes :Sulfonated Poly(ether sulfone) for Universal Fuel Cell Operations

    Institute of Scientific and Technical Information of China (English)

    Hyoung-Juhn Kim

    2005-01-01

    @@ 1Introduction Polymer electrolyte fuel cells (PEFCs) have been spotlighted because they are clean and highly efficient power generation system. Proton exchange membrane fuel cells (PEMFCs), which use reformate gases or pure H2 for a fuel, have been employed for automotives and residential usages. Also, liquid-feed fuel cells such as direct methanol fuel cell (DMFC) and direct formic acid fuel cell (DFAFC) were studied for portable power generation.

  6. Desenvolvimento motor e transtorno de desenvolvimento da coordenação

    OpenAIRE

    Bessa, Telma Catarina Cavadas

    2012-01-01

    Este trabalho teve como finalidade avaliar a coordenação motora e a presença de desordens da coordenação motora associadas a transtornos de desenvolvimento da coordenação (TDC) em crianças dos 7 aos 10 anos e adolescentes dos 11 aos 16 anos de idade. Utilizou-se a bateria de teste Movement Assessment Batery for Children-2 (MABC-2) de forma a avaliar as respetivas faixas etárias, relacionadas com a avaliar da coordenação motora e desordens de coordenação. Participaram 274 indivíduos (138...

  7. Construction and evaluation of a proton exchange fuel cell

    International Nuclear Information System (INIS)

    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/cm2 was achieved. The conditions to obtain the porous support were: composition of 15 % Teflon and 85 % carbon, pressure of 100 Kgf/cm2, 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

  8. 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].

  9. 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.

  10. 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.

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

    Energy Technology Data Exchange (ETDEWEB)

    Shamsuddin Ilias

    2002-06-11

    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.

  12. 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.

  13. 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...... of the FURIM are in three steps: (1) further improvement of the high temperature polymer membranes and related materials; (2) development of technological units including fuel cell stack, hydrocarbon reformer and afterburner, that are compatible with the HT-PEMFC; and (3) integration of the HT...... catalytic burner 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...

  14. 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)

  15. 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)

  16. 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

  17. 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

  18. 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

  19. 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 conditions...

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

    DEFF Research Database (Denmark)

    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...

  1. 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...

  2. Renewable energies - Fuel cell and hydrogen

    International Nuclear Information System (INIS)

    In July 2003 the Fuel Cell Program was established at IPEN in order to contribute to the national development in this area. The program was structured in a cross-cutting way involving human and infrastructure resources from IPEN Technical Departments. Three main areas were developed: PEMFC (Proton Exchange Membrane Fuel Cell): SOFC (Solid Oxide Fuel Cell); and REFORM (H2 production from ethanol reforming)

  3. 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.

  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. Platinum Porous Electrodes for Fuel Cells

    DEFF Research Database (Denmark)

    Andersen, Shuang Ma

    fundamental for the cell development, which is established on a sound understanding of the electrode structure and balance of protonic phase, electronic phase and gas phase. The scope of the work includes:  Electrode components characterization: permeability; particle size and atomic lattice; surface area...... 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.......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 is...

  6. 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.

  7. 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.

  8. Aprendizagem e Desenvolvimento na Teoria de Jean Piaget

    OpenAIRE

    Maria Suzana de Stefano Menin

    2009-01-01

    Neste artigo são apresentadas, segundo indicay6es de Castorina (1988), e desenvolvidas três etapas em que a teoria Psicogenetica de Jean Piaget debruçou-se sobre as relações entre aprendizagem e desenvolvimento buscando esclarece-las. Na primeira etapa, a teoria buscou diferenciar-se das posi96es empiristas e aprioristas afirmando todo o desenvolvimento cognitivo como construção gradual de estruturas. Na segunda, negou-se a possibilidade de apressar a construção de operações 16gicas atraves d...

  9. Estudos em desenvolvimento motor da criança VIII

    OpenAIRE

    Lopes, Vítor P.; Gonçalves, Celina

    2015-01-01

    O desenvolvimento motor infantil é sem dúvida alguma, uma das áreas de estudo que mais tem intrigado os investigadores em ciências do desenvolvimento humano. Os fatores genéticos associados a fatores ambientais têm vindo a criar desafios interessantes em compreender a complexidade do processo de evolução motora ao longo da vida e em particular nas primeiras idades. Temos vindo a assistir a grandes transformações sociais que provocaram grandes alterações dos estilos de vida das ...

  10. Desenvolvimento de um monitor de apneia pediátrico

    OpenAIRE

    Caldeira, Gonçalo José Martins

    2009-01-01

    O trabalho apresentado tem por base o desenvolvimento de um monitor de apneia do sono pediátrico. Aborda questões ao nível da fisiologia respiratória e da mecânica pulmonar de um indivíduo. Apresenta uma proposta de desenvolvimento de um monitor de aquisição e identificação de sinais respiratórios, a fim de efectuar a detecção da apneia do sono.

  11. Metodologia de desenvolvimento de novos produtos orientados para o mercado

    OpenAIRE

    Sousa, Carlos Eduardo Rodrigues de

    2012-01-01

    O desenvolvimento de novos produtos orientados para o mercado/cliente visa, na sua essência, identificar, compreender e analisar quais os ativos num produto que o cliente mais valoriza. Através de metodologias de orientação para o mercado, é possível identificar informação de valor sobre o mercado alvo, e, com base nesta informação, aplicar melhorias nas características e propriedades do novo produto desde o seu desenvolvimento. Tudo isto permitirá desenvolver novos produtos co...

  12. Desenvolvimento de pastas de azeitona e tremoço

    OpenAIRE

    Domingues, Joana Lopes

    2014-01-01

    Dissertação apresentada à Escola Superior Agrária do Instituto Politécnico de Castelo Branco para cumprimento dos requisitos necessários à obtenção do grau de Mestre em Inovação e Qualidade na Produção Alimentar. Este trabalho teve como principal objetivo o desenvolvimento de pastas de azeitona e tremoço, criando um alimento inovador, com uma melhor composição nutricional relativamente às pastas comummente comercializadas, sem aumentar o custo do produto. O desenvolvimento b...

  13. Effect of through-plane polytetrafluoroethylene distribution in gas diffusion layers on performance of proton exchange membrane fuel cells

    Science.gov (United States)

    Ito, Hiroshi; Iwamura, Takuya; Someya, Satoshi; Munakata, Tetsuo; Nakano, Akihiro; Heo, Yun; Ishida, Masayoshi; Nakajima, Hironori; Kitahara, Tatsumi

    2016-02-01

    This experimental study identifies the effect of through-plane polytetrafluoroethylene (PTFE) distribution in gas diffusion backing (GDB) on the performance of proton exchange membrane fuel cells (PEMFC). PTFE-drying under vacuum pressure created a relatively uniform PTFE distribution in GDB compared to drying under atmospheric pressure. Carbon paper samples with different PTFE distributions due to the difference in drying conditions were prepared and used for the cathode gas diffusion layer (GDL) of PEMFCs. Also investigated is the effect of MPL application on the performance for those samples. The current density (i) - voltage (V) characteristics of these PEMFCs measured under high relative humidity conditions clearly showed that, with or without MPL, the cell using the GDL with PTFE dried under vacuum condition showed better performance than that dried under atmospheric condition. It is suggested that this improved performance is caused by the efficient transport of liquid water through the GDB due to the uniform distribution of PTFE.

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

    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,...

  15. 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...... 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....

  16. Study on Production of Hydrogen from Methane for Proton Exchange Membrane Fuel Cell

    Institute of Scientific and Technical Information of China (English)

    宋正昶; 李传统

    2001-01-01

    The hydrogen production from methane for proton exchange membrane fuel cell (PEMFC) was studied experimentally. The conversion rate of methane under different steam-carbon ratios, the effect of the different excess air ratios on the constituents of the gas produced, the permeability of hydrogen under different pressure differences, and the effect of different system pressure on the reaction enthalpy of hydrogen were obtained. The results lay the basis for the production of hydrogen applicable to PEMFC, moreover, provide a new way for the comprehensive utilization of the coal bed methane.

  17. 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)

  18. Effects of microstructure characteristics of gas diffusion layer and microporous layer on the performance of PEMFC

    International Nuclear Information System (INIS)

    Water management is an important issue in proton exchange membrane (PEM) fuel cell design and operation. The purpose of this work is to investigate the effects of the microstructure characteristics of the gas diffusion layer (GDL) and microporous layer (MPL), including pore size distribution, hydrophobic treatment, gas permeability, and other factors, on the water management and performance of a PEM fuel cell. A commercial catalyst-coated membrane with an active area of 25 cm2 is used along with a GDL and an MPL for assembling a single cell. The effects of the MPL, the thickness of the MPL, the PTFE loading of carbon paper and MPL, and the baking time of the MPL have been investigated. Results show that the addition of MPL increases cell performance in the high current density region due to the elimination of mass transfer limitation. There exists an optimum thickness of MPL. Furthermore, increasing the MPL baking time enhances cell performance due to enlarged pore size and permeability.

  19. Lifetime prediction and the economic lifetime of Proton Exchange Membrane fuel cells

    International Nuclear Information System (INIS)

    Highlights: • A formula to predict the PEMFC lifetime is presented. • A PEMFC residual life evaluation method is presented. • The evaluation method realizes online forecasting of the PEMFC residual life. • The PEMFC economic lifetime is studied to confirm the best design lifetime. - Abstract: Lifetime and cost are two main factors that restrict the commercialization of Proton Exchange Membrane (PEM) fuel cells. This paper mainly studies the prediction and the evaluation methods of PEM fuel cell lifetime. A formula to predict the PEM fuel cell lifetime is presented. The formula is based on the vehicular operation records and the tested results in the lab. Also the difference between the vehicular operation condition and the test is taken into consideration. The formula realizes the PEM fuel cell lifetime rapid prediction. A PEM fuel cell residual life evaluation method is also presented. The evaluation method realizes online forecasting of the residual life through updating the environmental affecting factor and voltage degradation rate caused by the operating conditions. Furthermore, the PEM fuel cell economic lifetime is studied. The economic lifetime is the working lifetime which gains the lowest average cost. The synthesis of the lifetime and the cost provides a basis to confirm the best design lifetime

  20. 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

  1. Thermal analysis of air-cooled fuel cells

    OpenAIRE

    Shahsavari, Setareh

    2011-01-01

    Temperature distribution in a fuel cell significantly affects the performance and efficiency of the fuel cell system. Particularly, in low temperature fuel cells, improvement of the system requires proper thermal management, which indicates the need for developing accurate thermal models. In this study, a 3D numerical thermal model is presented to analyze the heat transfer and predict the temperature distribution in air-cooled proton exchange membrane fuel cells (PEMFC). In the modeled fuel c...

  2. Em busca de novas estratégias de desenvolvimento

    Directory of Open Access Journals (Sweden)

    Ignacy Sachs

    1995-12-01

    Full Text Available Na véspera da Conferência sobre desenvolvimento social em Copenhague (1995, o autor defende novas estratégias condizentes com uma axiologia do desenvolvimento. Para ele, não há desenvolvimento sem crescimento equilibrado dentro de cada país e nas relações Norte-Sul. Por outro lado, não se pode prescindir da ecologia. Finalmente o objetivo do desenvolvimento é o homem, sua cultura própria, seus valores universais: o direito à inserção produtiva e à participação enquanto cidadão, o que supõe um Estado democrático, regulador de uma economia mista. No plano jurídico, o autor sugere a criação de um foro internacional independente.On the eve of the International Social Conference in Copenhagen (1995, the author defends new strategies, suitable for a development axiology. According to him, there is no development without a balanced growth within each country and in the North-South relations. On the other hand, one cannot ignore ecology. Finally, the target of development is man, his own culture, his universal values: the right to a productive insertion and to the participation as a citizen. This pressuposes a democratic State, regulator of a mixed economy. At the juridic level, the author suggests the creation of an independent international forum.

  3. Valores e Desenvolvimento Humano [Values and Human Development

    NARCIS (Netherlands)

    F. Comim; A. Macedo de Jesus (Anderson); R.C.B Oliveira; A. Davison; S. Galeno; A. Ribeiro

    2010-01-01

    markdownabstract__Abstract__ | 19 A 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

  4. Graphene-Supported Platinum Catalyst-Based Membrane Electrode Assembly for PEM Fuel Cell

    Science.gov (United States)

    Devrim, Yilser; Albostan, Ayhan

    2016-08-01

    The aim of this study is the preparation and characterization of a graphene-supported platinum (Pt) catalyst for proton exchange membrane fuel cell (PEMFC) applications. The graphene-supported Pt catalysts were prepared by chemical reduction of graphene and chloroplatinic acid (H2PtCl6) in ethylene glycol. X-ray powder diffraction, thermogravimetric analysis (TGA) and scanning electron microscopy have been used to analyze structure and surface morphology of the graphene-supported catalyst. The TGA results showed that the Pt loading of the graphene-supported catalyst was 31%. The proof of the Pt particles on the support surfaces was also verified by energy-dispersive x-ray spectroscopy analysis. The commercial carbon-supported catalyst and prepared Pt/graphene catalysts were used as both anode and cathode electrodes for PEMFC at ambient pressure and 70°C. The maximum power density was obtained for the Pt/graphene-based membrane electrode assembly (MEA) with H2/O2 reactant gases as 0.925 W cm2. The maximum current density of the Pt/graphene-based MEA can reach 1.267 and 0.43 A/cm2 at 0.6 V with H2/O2 and H2/air, respectively. The MEA prepared by the Pt/graphene catalyst shows good stability in long-term PEMFC durability tests. The PEMFC cell voltage was maintained at 0.6 V without apparent voltage drop when operated at 0.43 A/cm2 constant current density and 70°C for 400 h. As a result, PEMFC performance was found to be superlative for the graphene-supported Pt catalyst compared with the Pt/C commercial catalyst. The results indicate the graphene-supported Pt catalyst could be utilized as the electrocatalyst for PEMFC applications.

  5. Graphene-Supported Platinum Catalyst-Based Membrane Electrode Assembly for PEM Fuel Cell

    Science.gov (United States)

    Devrim, Yilser; Albostan, Ayhan

    2016-06-01

    The aim of this study is the preparation and characterization of a graphene-supported platinum (Pt) catalyst for proton exchange membrane fuel cell (PEMFC) applications. The graphene-supported Pt catalysts were prepared by chemical reduction of graphene and chloroplatinic acid (H2PtCl6) in ethylene glycol. X-ray powder diffraction, thermogravimetric analysis (TGA) and scanning electron microscopy have been used to analyze structure and surface morphology of the graphene-supported catalyst. The TGA results showed that the Pt loading of the graphene-supported catalyst was 31%. The proof of the Pt particles on the support surfaces was also verified by energy-dispersive x-ray spectroscopy analysis. The commercial carbon-supported catalyst and prepared Pt/graphene catalysts were used as both anode and cathode electrodes for PEMFC at ambient pressure and 70°C. The maximum power density was obtained for the Pt/graphene-based membrane electrode assembly (MEA) with H2/O2 reactant gases as 0.925 W cm2. The maximum current density of the Pt/graphene-based MEA can reach 1.267 and 0.43 A/cm2 at 0.6 V with H2/O2 and H2/air, respectively. The MEA prepared by the Pt/graphene catalyst shows good stability in long-term PEMFC durability tests. The PEMFC cell voltage was maintained at 0.6 V without apparent voltage drop when operated at 0.43 A/cm2 constant current density and 70°C for 400 h. As a result, PEMFC performance was found to be superlative for the graphene-supported Pt catalyst compared with the Pt/C commercial catalyst. The results indicate the graphene-supported Pt catalyst could be utilized as the electrocatalyst for PEMFC applications.

  6. Coxa vara do desenvolvimento Developmental coxa vara

    Directory of Open Access Journals (Sweden)

    Miguel Akkari

    2010-12-01

    Full Text Available OBJETIVO: Avaliar os aspectos clínicos e radiográficos observados após o tratamento operatório de pacientes portadores de coxa vara do desenvolvimento (CVD, além de revisar sua epidemiologia e história natural. MÉTODOS: Foram selecionados 19 pacientes (26 quadris portadores de CVD submetidos à osteotomia valgizante subtrocantérica, com tempo médio de quatro anos e 10 meses e mínimo de 12 meses de seguimento. Foram analisadas a amplitude de movimento dos quadris, o sinal de Trendelenburg e a discrepância de comprimento dos membros inferiores. Na avaliação radiográfica, foi medido o ângulo epifisodiafisário (ED e a distância articulotrocantérica (DAT em diferentes momentos. RESULTADOS: Observou-se elevação média de 21º da amplitude de abdução dos quadris, assim como desaparecimento do sinal de Trendelenburg. Na avaliação da discrepância de comprimento, 72,2% dos 18 pacientes analisados foram equalizados, considerando uma diferença residual de até 0,5cm entre os membros. A variação da DAT apresentou médias de -0,34cm no período pré-operatório, 2,18cm no pós-operatório imediato e 1,35cm na última avaliação, o ângulo ED apresentou uma média de 91° no pré-operatório, 142° no pós-operatório imediato e 133° na última avaliação. CONCLUSÃO: A osteotomia valgizante subtrocantérica, levando a ângulos epifisodiafisários próximos a 140°, foi eficiente ao longo do tempo na correção das deformidades.OBJECTIVE: To evaluate the clinical and radiographic findings observed after surgical treatment of patients with developmental coxa vara (DCV and review its epidemiology and natural history. METHOD: We selected 19 patients (26 hips with DCVthat underwent subtrochanteric osteotomy with a mean follow-up period of four years and ten months and a minimum of 12 months of follow-up. We analyzed the range of motion of the hips, the Trendelenburg sign, and the discrepancy of the length of the lower limbs.In the

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

    DEFF Research Database (Denmark)

    Li, Qingfeng; He, Ronghuan; Gao, Ji-An; Jensen, Jens Oluf; Bjerrum, Niels

    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...

  8. Development of HT-PEMFC components and stack for CHP unit

    Energy Technology Data Exchange (ETDEWEB)

    Jensen, Jens Oluf; Li, Q. (Technical Univ. of Denmark, Dept. of Chemistry, Kgs. Lyngby (Denmark)); Terkelsen, C.; Rudbech, H.C.; Steenberg, T. (Danish Power System Aps, Charlottenlund (Denmark)); Thibault de Rycke (IRD Fuel Cell A/S, Svendborg (Denmark))

    2009-10-15

    The aim of the project has been to further develop components for an all Danish high temperature PEM fuel cells stack for application in combined heat and power units (CHP units). The final product aimed at was a 1.5-2 kW stack for operation at 150-200 deg. C. The project follows the previous PSO project 4760, 'High Temperature PEM Fuel Cell'. The project has addressed the HT-PEM fuel cells form a components point of view and the materials here for. The main areas were polymer and membrane development, electrode and MEA development (MEA = membrane electrode assembly, i.e. the cells.) and stack development. The membrane development begins with the polymer. The polymerization technique was improved significantly in two ways. Better understanding of the process and the critical issues has led to more reproducible results with repeated high molecular weights. The molecular weight is decisive for the membrane strength and durability. The process was also scaled up to 100-200 g polymer pr. batch in a new polymerization facility build during the project. It is dimensioned for larger batches too, but this was not verified during the project. The polymer cannot be purchased in the right quality for fuel cell membranes and it is important that it manufacture is not a limiting factor at the present state. Experiments with other membrane casting techniques were also made. The traditional PBI doped with phosphoric acid is still the state of art membrane for the HT-PEM fuel cells, but progress was also made with modified membranes. Different variants of PBI were synthesized and tested. Electrodes have been manufactured by a spray technique in contrast to the previously applied tape casting. The hand held spray gun previously led to an improvement of the electrodes, but the reproducibility was limited. Subsequently the construction of a semi automated spray machine was started and results like of the best hand sprayed electrodes were obtained. A viable way of MEA rim

  9. High temperature polymer electrolyte membrane fuel cell

    Institute of Scientific and Technical Information of China (English)

    K.Scott; M. Mamlouk

    2006-01-01

    One of the major issues limiting the introduction of polymer electrolyte membrane fuel cells (PEMFCs) is the low temperature of operation which makes platinum-based anode catalysts susceptible to poisoning by the trace amount of CO, inevitably present in reformed fuel. In order to alleviate the problem of CO poisoning and improve the power density of the cell, operating at temperature above 100 ℃ is preferred. Nafion(R) -type perfluorosulfonated polymers have been typically used for PEMFC. However, the conductivity of Nafion(R) -type polymers is not high enough to be used for fuel cell operations at higher temperature ( > 90 ℃) and atmospheric pressure because they dehydrate under these condition.An additional problem which faces the introduction of PEMFC technology is that of supplying or storing hydrogen for cell operation,especially for vehicular applications. Consequently the use of alternative fuels such as methanol and ethanol is of interest, especially if this can be used directly in the fuel cell, without reformation to hydrogen. A limitation of the direct use of alcohol is the lower activity of oxidation in comparison to hydrogen, which means that power densities are considerably lower. Hence to improve activity and power output higher temperatures of operation are preferable. To achieve this goal, requires a new polymer electrolyte membrane which exhibits stability and high conductivity in the absence of liquid water.Experimental data on a polybenzimidazole based PEMFC were presented. A simple steady-state isothermal model of the fuel cell is also used to aid in fuel cell performance optimisation. The governing equations involve the coupling of kinetic, ohmic and mass transport. This paper also considers the advances made in the performance of direct methanol and solid polymer electrolyte fuel cells and considers their limitations in relation to the source and type of fuels to be used.

  10. Numerical investigation of the coupled water and thermal management in PEM fuel cell

    International Nuclear Information System (INIS)

    Highlights: ► A fully coupled, non-equilibrium, anisotropic PEM fuel cell computational model is developed. ► The coupled water and heat transport processes are numerically investigated. ► Anisotropic property of gas diffusion layer has an effect on local cell performance. ► The boundary temperature greatly affects the cell local temperature and indirectly influences the saturation profile. ► The cathode gas inlet humidity slightly affects the local temperature distribution. - Abstract: Water and thermal managements are the most important issue in the operation and optimization of proton exchange membrane fuel cell (PEMFC). A three-dimensional, two-phase, non-isothermal model of PEMFC is presented in this paper. The model is used to investigate the interaction between water and thermal transport processes, the effects of anisotropic characters of gas diffusion layer, different boundary temperature of flow plate and the effect of gas inlet humidity. By comparing the numerical results of different cases, it is found that maximum cell temperature is higher in the isotropic gas diffusion layer; in contrast, the liquid saturation is lower than other case. Moreover, the boundary temperature greatly affects the temperature distribution in PEMFC, and indirectly influences the water saturation distribution. This indicates that the coupled relationship between water and thermal managements cannot be ignored, and these two processes must be considered simultaneously in the optimization of PEMFC

  11. A Comparison of Fick and Maxwell-Stefan Diffusion Formulations in PEMFC Cathode Gas Diffusion Layers

    CERN Document Server

    Lindstrom, Michael

    2013-01-01

    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. Formulations of diffusion combined with mass-averaged Darcy flow are considered for three component gases. Fick formulations can be considered as approximations of Maxwell-Stefan in a certain sense. For this application, the formulations can be compared computationally in a simple, one dimensional setting. We observe that the predictions of the formulations are very similar, despite their seemingly different structure. Analytic insight is given to the result. In addition, it is seen that for both formulations, diffusion laws are small perturbations from bulk flow. The work is also intended as a reference to multi-component gas diffusion formulations in the fuel cell setting.

  12. Poly(vinylimidazole) radiografted PVDF nanospheres as alternative binder for high temperature PEMFC electrodes

    Science.gov (United States)

    Galbiati, Samuele; Coulon, Pierre-Eugène; Rizza, Giancarlo; Clochard, Marie-Claude; Castellino, Micaela; Sangermano, Marco; Nayoze, Christine; Morin, Arnaud

    2015-11-01

    Within the framework of high-temperature polymer fuel cells doped with phosphoric acid, we investigate the replacement of the conventional binder in the catalyst layers by functionalized solid PVDF nanospheres. Aim of this study is to develop and test an innovative binder which might create enhanced electrode porosity and acid distribution. Aqueous suspensions of PVDF nanospheres (d ∼ 200 nm) are obtained by radical emulsion polymerization and are functionalized by Vinyl-Imidazole (VI) groups via in situ γ-radiation. As a consequence the nanospheres can interact with H3PO4 to obtain proton conductivity. Catalyst inks are prepared mixing the nanospheres with commercial Pt/C electrocatalyst powder, solvents and phosphoric acid. Prototype electrodes are deposited by spraying and preliminary fuel cell tests are carried out at 160 °C under dry H2/air. Electrodes with grafted PVDF nanospheres as solid binder are demonstrated and its understanding is in progress. Further improvements are outlined.

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

    Science.gov (United States)

    Lindstrom, Michael; Wetton, Brian

    2016-04-01

    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.

  14. 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.

  15. 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)

  16. High-performance membrane-electrode assembly with an optimal polytetrafluoroethylene content for high-temperature polymer electrolyte membrane fuel cells

    Science.gov (United States)

    Jeong, Gisu; Kim, MinJoong; Han, Junyoung; Kim, Hyoung-Juhn; Shul, Yong-Gun; Cho, EunAe

    2016-08-01

    Although high-temperature polymer electrolyte membrane fuel cells (HT-PEMFCs) have a high carbon monoxide tolerance and allow for efficient water management, their practical applications are limited due to their lower performance than conventional low-temperature PEMFCs. Herein, we present a high-performance membrane-electrode assembly (MEA) with an optimal polytetrafluoroethylene (PTFE) content for HT-PEMFCs. Low or excess PTFE content in the electrode leads to an inefficient electrolyte distribution or severe catalyst agglomeration, respectively, which hinder the formation of triple phase boundaries in the electrodes and result in low performance. MEAs with PTFE content of 20 wt% have an optimal pore structure for the efficient formation of electrolyte/catalyst interfaces and gas channels, which leads to high cell performance of approximately 0.5 A cm-2 at 0.6 V.

  17. 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.

  18. 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

  19. Experimental investigation of dynamic responses of a transparent PEM fuel cell to step changes in cell current density with operating temperature

    International Nuclear Information System (INIS)

    The dynamic responses of a proton exchange membrane fuel cell (PEMFC) are closely related to the novel water management technique used for the efficient operation of automotive PEMFCs. In order to better understand the dynamic water transport during cell transients, this paper presents an experimental investigation of the transient response of a cell under fully humidified conditions. The cell dynamic performance was measured by employing a transparent cell and investigated with visualization images of the water distribution in the flow channels. Furthermore, the effect of the operating temperature on the cell transients was examined. The results show that the cell dynamic behavior for the tested operating temperature (30-50 .deg. C) conditions is mainly governed by water transport characteristics related to cathode flooding. Also, we show that the time needed for the cell to reach steady-state after a current density step increase is retarded due to excessive water accumulation inside the cell at lower operating temperatures

  20. meta-PBI/methylated PBI-OO blend membranes for acid doped HT PEMFC

    DEFF Research Database (Denmark)

    Cho, Hyeongrae; Hur, Eun; Henkensmeier, Dirk; Jeong, Gisu; Cho, Eunae; Kim, Hyoung Juhn; Jang, Jong Hyun; Lee, Kwan Young; Hjuler, Hans Aage; Li, Qingfeng; Jensen, Jens Oluf; Cleemann, Lars Nilausen

    2014-01-01

    Methylation of polybenzimidazole leads to positively charged polymer backbones, and moveable anions. Ion exchange of methylated PBI-OO in phosphoric acid (PA) shows that the resulting polymers dissolve. meta-PBI, however, absorbs about 400wt% PA while remaining a self supported membrane. We inves...... the fuel cell, blend membranes show similar or better performance than meta-PBI. In the TGA, blends doped in 20% PA showed a stable plateau between 115 and 180°C, while meta-PBI lost weight continuously....

  1. 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

  2. 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

  3. Corrosion behavior of TiN coated type 316 stainless steel in simulated PEMFC environments

    International Nuclear Information System (INIS)

    The corrosion behavior of TiN coated type 316 stainless steel (SS) was investigated in simulated proton exchange membrane fuel cell environments, i.e. 0.01 M HCl + 0.01 M Na2SO4 solutions bubbled with pure oxygen and hydrogen gases, respectively, by using electrochemical measurement techniques. 316SS substrate can passivate spontaneously in simulated cathode environment, while it is in active state at the corrosion potential in simulated anode environment. TiN coatings have much better corrosion resistance and passivity under both simulated conditions. No significant degradation takes place in TiN coatings under the typical load conditions of fuel cell for 4 h. The loss of small part of coatings occurs during the immersion tests of TiN coatings in the oxygen environment for 1000 h and in the hydrogen environment for 240 h, respectively, but the exposed substrate areas are passivated in both environments. The results reveal that TiN coating can offer 316SS higher corrosion resistance and electric conductivity, and that further effort to improve the coating quality and to evaluate the long-term stability of 316SS/TiN coating systems under simulated conditions are deserved. In addition, the characteristics of corrosion process for TiN coatings on passivatable substrate were discussed in detail

  4. 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)

  5. Optimization of catalyst layer composition for PEMFC using graphene-based oxygen reduction reaction catalysts

    Science.gov (United States)

    Park, Jong Cheol; Park, Sung Hyeon; Chung, Min Wook; Choi, Chang Hyuck; Kho, Back Kyun; Woo, Seong Ihl

    2015-07-01

    The focus in recent years is on developing high performance non-precious metal catalysts (NPMCs) to reduce the catalyst cost in fuel cells. However, little attention has been paid to improve the utilization of NPMCs. Thus, this study focuses on the optimization of electrode component, particularly the Nafion content. With the synthesized graphene based oxygen reduction reaction (ORR) catalyst, the catalyst inks were prepared at various Nafion contents with suitable amounts of catalysts sprayed on the gas diffusion media. Twenty different single cells were assembled and measured for polarization, resistance and electrochemical impedance. Electrodes of 66.7 and 50.0% Nafion contents showed the highest performance for hydrogen/oxygen and hydrogen/air operation, respectively. These results were explained using the electrochemical impedance spectra, where the highest performance electrode resulted with the lowest charge transfer resistance. Moreover, negligible change in performance was observed during the 80 h of stability test. The optimization compositions of NPMC-based MEAs were very different to Pt-based MEAs, indicating the importance of optimization studies for the practical use of NPMCs.

  6. Parametric analysis of an irreversible proton exchange membrane fuel cell/absorption refrigerator hybrid system

    International Nuclear Information System (INIS)

    A hybrid system mainly consisting of a PEMFC (proton exchange membrane fuel cell) and an absorption refrigerator is proposed, where the PEMFC directly converts the chemical energy contained in the hydrogen into electrical and thermal energies, and the thermal energy is transferred to drive the bottoming absorption refrigerator for cooling purpose. By considering the existing irreversible losses in the hybrid system, the operating current density region of the PEMFC permits the absorption refrigerator to exert its function is determined and the analytical expressions for the equivalent power output and efficiency of the hybrid system under different operating conditions are specified. Numerical calculations show that the equivalent maximum power density and the corresponding efficiency of the hybrid system can be respectively increased by 5.3% and 6.8% compared to that of the stand-alone PEMFC. Comprehensive parametric analyses are conducted to reveal the effects of the internal irreversibility of the absorption refrigerator, operating current density, operating temperature and operating pressure of the PEMFC, and some integrated parameters related to the thermodynamic losses on the performance of the hybrid system. The model presented in the paper is more general than previous study, and the results for some special cases can be directly derived from this paper. - Highlights: • A CHP system composed of a PEMFC and an absorption refrigerator is proposed. • Current density region enables the absorption refrigerator to work is determined. • Multiple irreversible losses in the system are analytically characterized. • Maximum power density and corresponding efficiency can be increased by 5.3% and 6.8%. • Effects of some designing and operating parameters on the performance are discussed

  7. Acid-doped Polybenzimidazole Membranes as Electrolyte for Fuel Cells Operating Above 100°C

    DEFF Research Database (Denmark)

    Qingfeng, Li; Jensen, Jens Oluf; He, Ronhuan; Gang, Xiao; Gao, Ji-An; Berg, Rolf W.; Hjuler, Hans Aage; Hennesø, Erik; Bjerrum, Niels

    high 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. A high temperature PEMFC system operational at up to 200°C is demonstrated with no gas...

  8. Understanding on Interface Contribution to the Electrode Performance of Proton Exchange Membrane Fuel Cells

    DEFF Research Database (Denmark)

    Andersen, Shuang Ma; Grahl-Madsen, L.

    2016-01-01

    The commercialization of proton exchange membrane fuel cells (PEMFCs) is closer to the reality than ever before. Electrode interface development can bring a boost to the last few steps. Here, we explore electrode properties from its interface structure, especially the ionomer phase. Electrodes...

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

    International Nuclear Information System (INIS)

    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

  10. Application of CFD techniques in the modelling and simulation of PBI PEMFC

    Energy Technology Data Exchange (ETDEWEB)

    Doubek, G.; Robalinho, E.; Cunha, E.F.; Linardi, M. [IPEN - Av. Prof. Lineu Prestes, 2242, 05508-000, Sao Paulo (Brazil); Cekinski, E. [IPT - Av. Prof. Almeida Prado, 532, 05508-901, Sao Paulo (Brazil)

    2011-12-15

    In the present work two 3-D models, for the catalytic layer, were employed in order to simulate the responses of a PBI high temperature polymeric membrane fuel cell. The simulations made use of an agglomerate model and a pseudo-homogenous model, both implemented taking into account the temperature influence over their parameters. The overall simulation was performed also as two models, linked by the variable pressure, one for the whole graphite plate simulating the distribution channels, and the other dealing with the MEA and thereof the catalytic layer. A discussion over the two models was done and the experimental results demonstrated that the pseudo-homogeneous obtained the better fits. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  11. Optimization of perfluorosulphonic ionomer amount in gas diffusion electrodes for PEMFC operation under automotive conditions

    International Nuclear Information System (INIS)

    Highlights: • Evaluation of the influence of ionomer amount in the catalytic layer as a function of operating conditions. • Optimisation of ionomer amount in the catalytic layer as a function of polymer characteristics (hydrophobic/hydrophilic) and operative conditions. • An ionomer amount of 50 wt% in the catalytic layer is the best compromise to work at 110 °C low RH and low pressure. - ABSTRACT: Perfluorinated sulphonic acid (PFSA) polymers such as Nafion® are widely used for both electrolyte membrane and ionomer in the catalytic layer because of their high proton conductivity (σH) as well as chemical and thermal stability. When PFSA polymers alternative to Nafion® with a different EW are used, it is necessary to optimize the composition of the catalytic ink, considering the different ionomer characteristics. Moreover, fuel cell operating conditions play an important role regarding the catalytic layer optimization. In this work, the influence of ionomer amount in the catalytic layer was evaluated. The electrochemical studies were carried out in a single cell in H2–O2 at intermediate temperatures (80 °C–130 °C) by using a fumapem® F-950 membrane as an electrolyte. A hydro-alcoholic dispersion of fumion® F was also used as an ionomer in the electrode catalytic structure with an amount ranging from 30 to 60%. Under operating conditions finalised to automotive applications (intermediate temperature, low relative humidity and low pressure of gases) an improvement of performance in terms of maximum power density was obtained by using optimized ionomer content

  12. Sliding Mode Control of the Battery Bank for the Fuel Cell-based Distributed Generation System

    OpenAIRE

    Junsheng Jiao

    2013-01-01

    The dynamic models for the fuel cell power and the configuration of the fuel cell distributed generation system are shown in this paper. Due to nonlinear characteristics of fuel cell model, the output voltage of fuel cell varies greatly when the load changes. A novel interface is designed to provide a constant output voltage for charging of the battery bank of the fuel cell distributed generation. The thesis presents a sliding mode control design of PEMFC distributed generation system. A casc...

  13. State of the Art of Fuel Cells for Ship Applications

    OpenAIRE

    HAN, Jingang; Charpentier, Jean-Frederic; Tang, Tianhao

    2012-01-01

    Fuel cells promise to be far more efficient, produce lower or zero emissions, and operate cleaner than conventional internal-combustion engine and gas turbine. They are already used for transportation application (buses, cars and tramways). Fuel cells can also be an interesting solution for ships power. However the developments of fuel cell systems for ship are in infancy. The only exception is the PEMFC in the submarines. This solution allows obtaining an air-independent propulsion (AIP) ...

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

    Science.gov (United States)

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

    2016-01-01

    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.

  15. Theoretical modeling of the PEMFC catalyst layer: A review of atomistic methods

    International Nuclear Information System (INIS)

    This article reviews recent progress in the catalyst layer modeling of polymer electrolyte membrane fuel cells. Theoretical modeling is important to understand the basic chemical, and physical phenomena at the atomistic level in materials and relating these fundamentals to the properties and performance of the catalyst layer. Two fundamentally important theoretical methods have been chosen to represent atomistic models, namely density functional theory (DFT) and classical molecular dynamics. In addition, some reactive force field models are highlighted, and the mathematical framework is sufficiently described. The literature review includes important contributions that help to understand the oxygen reduction reaction including gas-phase reaction trends, and the solvation effects are also presented. Moreover, the electric field effect is discussed along with the recently established double reference method in the DFT framework. Using two atomistic simulations based on different axiomatic theories, the production of current density in the molecular junctions is considered with respect to voltage, elucidating applications to simple systems. The models of water transportation via polymer electrolyte membrane, as well as the catalyst and support oxidation are described. Epoxidized carbon support, oxidizable metal-oxide support and electron localization function analysis have provided insights for improving catalyst support material and enable characterization of the bonding between the catalyst and support. Conclusions and future outlook are outlined at the end. Thus the present work enlightens the future of the catalyst modeling towards more realistic models

  16. Leitura, literatura e desenvolvimento da competência textual

    OpenAIRE

    Sousa, Otília de; Sepúlveda, Angélica; Lourenço, Manuela; Correia, Ana

    2013-01-01

    A investigação sobre aprendizagem de leitura e escrita indica que nas práticas educativas cujo centro são livros há lugar a numerosas oportunidades para que as crianças aprendam sobre a língua e os textos. Na perspetiva do estudo do desenvolvimento da linguagem e da eficácia das práticas de ensino baseadas na leitura de textos literários há evidências da relação entre o trabalho à volta dos livros e da leitura e o desenvolvimento da linguagem e da competência discursiva, nomeadame...

  17. Pólos de competitividade, dinamizadores do desenvolvimento regional

    OpenAIRE

    Ferreira, Maria Joana e Caldas

    2008-01-01

    Este trabalho pretende discutir a importância das regiões na implementação do desenvolvimento sustentável, baseado na formação de pólos de competitividade que representem concentrações de actividades económicas ligadas às potencialidades de cada região, com vista a garantir o desenvolvimento regional. Interessa analisar a posição estratégica das regiões de Mira e Condeixa-a-Nova, se podem constituir por si só regiões eficientes ou a sua dimensão apenas lhes permite integrar redes de cooper...

  18. 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.

  19. PEMFC Cathode Catalyst Contamination Evaluation with a RRDE- Propene and Naphthalene

    International Nuclear Information System (INIS)

    The effects of two unsaturated hydrocarbons, C3H6 and C10H8, on the oxygen reduction reaction (ORR) at Pt/C electrodes were investigated using the rotating ring disk electrode (RRDE) method. Cyclic voltammetry (CV) measurements were performed to evaluate the electrochemical surface area losses. C3H6 coverage is found to be mass transfer and potential dependent. C10H8 is found to maintain high coverage across the whole potential range, independent of the mass transfer rates. The ORR kinetics is influenced by the hydrocarbon adsorption effect, and the mass activity decreases to lower values accordingly. The H2O2 collected on the ring also increases greatly due to the influence of the two contaminants, and this increase corresponds to an increase in the 2-electron O2 reduction route. The increase in H2O2 production and decrease in the charge transfer number is ascribed to spatial limitations arising from the adsorption of the contaminants because the rupture of the O-O bond requires two adjacent Pt active sites. The ring current collected on the C3H6-contaminated Pt surface differs greatly for the forward and reverse scans due to the interference of C3H6 reduction and the change in electrode coverage. Increases in the Tafel slopes are observed to a different extent for the different contaminants, which indicates that electron transfer for ORR at the electrode surface is manipulated by contaminant adsorption. A nearly full recovery was achieved for the C3H6-contaminated surface, indicating that C3H6 can be sufficiently removed by stop injection in in situ cell tests. Only partial recovery was obtained for C10H8-contaminated electrodes, with the unrecovered performance due to the high affinity of C10H8 for the Pt/C electrode, which requires high potential for oxidative removal

  20. Comparative analysis between a PEM fuel cell and an internal combustion engine driving an electricity generator: Technical, economical and ecological aspects

    International Nuclear Information System (INIS)

    In the recent years the fuel cells have received much attention. Among various technologies, the Proton Exchange Membrane Fuel Cell (PEMFC) is currently the most appropriate and is used in several vehicles prototype. A comparative technical, economical and ecological analysis between an Internal Combustion Engine fueled with Diesel driving an electricity Generator (ICE-G) and a PEMFC fed by hydrogen produced by ethanol steam reforming was performed. The technical analysis showed the advantages of the PEMFC in comparison to the ICE-G based in energetic and exergetic aspects. The economic analysis shows that fuel cells are not economic competitive when compared to internal combustion engine driving an electricity generator with the same generation capacity; it will only be economically feasible in a long term; due to the large investments required. The environmental analysis was based on concepts of CO2 equivalent, pollution indicator and ecological efficiency. Different to the ICE-G system, the Fuel Cell does not emit pollutants directly and the emission related to this technology is linked mainly with hydrogen production. The ecological efficiency of PEMFC was 96% considering the carbon dioxide cycle, for ICE-G system this parameter reach 51%. -- Highlights: • The exergetic efficiency of ICE-G was 22% and for the fuel cell was 40%. • The PEM fuel cell at long-term become economically competitive compared to ICE-G. • The ecological efficiency of PEM fuel cell was 96% and Diesel ICE-G was 51%

  1. Desenvolvimento e análise de células solares industriais em silício multicristalino com somente uma difusão de fósforo Development and analysis of industrial solar cells in multicrystalline silicon with single phosphorus diffusion

    Directory of Open Access Journals (Sweden)

    Gabriela Wehr

    2012-09-01

    Full Text Available O crescimento do mercado de células solares e a necessidade de substratos de menor custo tornam o silício multicristalino a principal alternativa para a fabricação de tais células. O objetivo desse artigo é apresentar o desenvolvimento de um processo industrial para fabricação de células solares em silício multicristalino com somente uma difusão de fósforo e metalização por serigrafia. Por meio de simulações, foram otimizados o emissor n+ e a malha de metalização. Também foram analisadas a influência da largura das trilhas e a influência do tempo de vida dos minoritários. Experimentalmente, foi avaliada a influência do processo de queima das pastas de metalização. De acordo com as simulações, o valor da resistência de folha deve ser maior que 50 Ω/□, para que a eficiência não diminua. Também se concluiu que a eficiência diminui de 0,3% a 0,5%, quando a largura das trilhas da malha de metalização é dobrada. Dos resultados experimentais, constatou-se que a temperatura de queima das pastas de metalização afeta, concretamente, a eficiência. A maior eficiência alcançada foi de 11,5%, para a temperatura de queima de 860°C.The market growth and the need of low cost materials make multicrystalline silicon the main alternative for the solar cell industry. The goal of this article is to present the development of an industrial process for manufacturing multicrystalline silicon solar cells by using only one phosphorus diffusion and screen printing metallization. The n+ emitter and the metallic grid were optimized through simulations and the influence of the width of the metal fingers and the bulk minority carrier lifetime were also analyzed. The influence of the firing conditions of the metal pastes was experimentally studied. According to the results obtained from the simulations, the value of the sheet resistance must be greater than 50 Ω/□ in order to maintain the efficiency of the solar cells. We also

  2. A new state-observer of the inner PEM fuel cell pressures for enhanced system monitoring

    Science.gov (United States)

    Bethoux, Olivier; Godoy, Emmanuel; Roche, Ivan; Naccari, Bruno; Amira Taleb, Miassa; Koteiche, Mohamad; Nassif, Younane

    2014-06-01

    In embedded systems such as electric vehicles, Proton exchange membrane fuel cell (PEMFC) has been an attractive technology for many years especially in automotive applications. This paper deals with PEMFC operation monitoring which is a current target for improvement for attaining extended durability. In this paper, supervision of the PEMFC is done using knowledge-based models. Without extra sensors, it enables a clear insight of state variables of the gases in the membrane electrode assembly (MEA) which gives the PEMFC controller the ability to prevent abnormal operating conditions and associated irreversible degradations. First, a new state-observer oriented model of the PEM fuel cell is detailed. Based on this model, theoretical and practical observability issues are discussed. This analysis shows that convection phenomena can be considered negligible from the dynamic point of view; this leads to a reduced model. Finally a state-observer enables the estimation of the inner partial pressure of the cathode by using only the current and voltage measurements. This proposed model-based approach has been successfully tested on a PEM fuel cell simulator using a set of possible fault scenarios.

  3. Metal foams application to enhance cooling of open cathode polymer electrolyte membrane fuel cells

    Science.gov (United States)

    Sajid Hossain, Mohammad; Shabani, Bahman

    2015-11-01

    Conventional channel flow fields of open cathode Polymer Electrolyte Membrane Fuel Cells (PEMFCs) introduce some challenges linked to humidity, temperature, pressure and oxygen concentration gradients along the conventional flow fields that reduce the cell performance. According to previous experimental reports, with conventional air flow fields, hotspot formation due to water accumulation in Gas Diffusion Layer (GDL) is common. Unlike continuous long flow passages in conventional channels, metal foams provide randomly interrupted flow passages. Re-circulation of fluid, due to randomly distributed tortuous ligaments, enhances temperature and humidity uniformity in the fluid. Moreover, the higher electrical conductivity of metal foams compared to non-metal current collectors and their very low mass density compared to solid metal materials are expected to increase the electrical performance of the cell while significantly reducing its weight. This article reviews the existing cooling systems and identifies the important parameters on the basis of reported literature in the air cooling systems of PEMFCs. This is followed by investigating metal foams as a possible option to be used within the structure of such PEMFCs as an option that can potentially address cooling and flow distribution challenges associated with using conventional flow channels, especially in air-cooled PEMFCs.

  4. A novel cogeneration system: A proton exchange membrane fuel cell coupled to a heat transformer

    International Nuclear Information System (INIS)

    This study focuses on the potential of a novel cogeneration system which consists of a 5 kW proton exchange membrane fuel cell (PEMFC) and an absorption heat transformer (AHT). The dissipation heat resulting from the operation of the PEMFC would be used to feed the absorption heat transformer, which is integrated to a water purification system. Therefore, the products of the proposed cogeneration system are heat, electricity and distilled water. The study includes a simulation for the PEMFC as well as experimental results obtained with an experimental AHT facility. Based on the simulation results, experimental tests were performed in order to estimate the performance parameters of the overall system. This is possible due to the matching in power and temperatures between the outlet conditions of the simulated fuel cell and the inlet requirements of the AHT. Experimental coefficients of performance are reported for the AHT as well as the overall cogeneration efficiency for the integrated system. The results show that experimental values of coefficient of performance of the AHT and the overall cogeneration efficiency, can reach up to 0.256 and 0.571, respectively. This represents an increment in 12.4% of efficiency, compared to the fuel cell efficiency working individually. This study shows that the combined use of AHT systems with a PEMFC is possible and it is a very feasible project to be developed in the Centro de Investigación en Energía (Centre of Energy Research), México.

  5. Brincadeira e desenvolvimento infantil: um olhar sociocultural construtivista

    Directory of Open Access Journals (Sweden)

    Norma Lucia Neris de Queiroz

    2006-08-01

    Full Text Available Como e por que as crianças brincam? Qual o significado desta atividade em cada cultura? Estas questões da temática da brincadeira e sua relevância para a compreensão científica do desenvolvimento infantil são discutidas neste estudo. Analisa-se o conceito da atividade de brincar a partir de diferentes autores, privilegiando quem a vê como socialmente construída. Aborda-se a importância da brincadeira do faz-de-conta como atividade que promove a representação e a metarepresentação no desenvolvimento da criança. Finalmente reflete-se sobre a brincadeira no contexto pedagógico vivenciado pelas crianças em instituições de educação infantil, o papel do professor no desenvolvimento e educação infantil.

  6. 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.

  7. Aprendizagem e Desenvolvimento na Teoria de Jean Piaget

    Directory of Open Access Journals (Sweden)

    Maria Suzana De Stefano Menin

    2009-12-01

    Full Text Available Neste artigo são apresentadas, segundo indicay6es de Castorina (1988, e desenvolvidas três etapas em que a teoria Psicogenetica de Jean Piaget debruçou-se sobre as relações entre aprendizagem e desenvolvimento buscando esclarece-las. Na primeira etapa, a teoria buscou diferenciar-se das posi96es empiristas e aprioristas afirmando todo o desenvolvimento cognitivo como construção gradual de estruturas. Na segunda, negou-se a possibilidade de apressar a construção de operações 16gicas atraves de treinos baseados em aprendizagens estritas, por associação e reforço, de respostas corretas. Na terceira etapa a teoria Psicogenetica buscou responder às indagações sobre as possibilidades de se promover o desenvolvimento através da apresentação de situações de desequilíbriocognitivo.

  8. Materials, design, and modeling for bipolar/end plates in polymer electrolyte membrane fuel cells

    Science.gov (United States)

    Kumar, Atul

    New vehicle technologies are required to improve upon conventional internal combustion engine technologies. In this regard, the development of fuel cell (polymer electrolyte membrane type) vehicles with improved efficiency and reliability seems promising. However, some technical issues exist that hinder the commercialization of this technology. One such issue is the high cost, volume, and mass of the bipolar/end plates in the polymer electrolyte membrane fuel cell (PEMFC) stack. This research, therefore, focuses on materials, design, and modeling for bipolar/end plates in PEMFC stack. Alternative materials were tested that can replace the conventionally used graphite in the PEMFC stack. With regards to these, a two-cell PEMFC stack was fabricated with SS-316 multi-parallel flow-field (MPFF) designed bipolar/end plates. The stack was run for over 1000 hours and showed no appreciable drop in performance. To enhance the understanding and for determining the effect of operating parameters in PEMFC, a single cell model was developed. The model results agree well with the experimental data. The gas flow-field in bipolar/end plates of the PEMFC was optimized with respect to channel dimensions, channel shape, flow-field design, and flow-field permeability. It was seen that lower the flow-field permeability better is the fuel cell performance. Based on this, the concept of use of metal foams in the gas flow-field was proposed. Experiments were carried out to test the feasibility of metal foams in the gas flow-field of bipolar/end plates in PEMFC stack. Three different porous materials, viz. Ni-Cr metal foam (50 P PI, pores per inch), S S-316 metal foam (20 PPI), and carbon cloth were tested, and the results were compared to the conventional MPFF channel design concept. It was seen that the performance with Ni-Cr metal foam was highest, and decreased in the order of SS-316 metal foam, conventional MPFF design, and carbon cloth. This trend was explained based on the effective

  9. 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

  10. Fuel cell engineering

    CERN Document Server

    Sundmacher

    2012-01-01

    Fuel cells are attractive electrochemical energy converters featuring potentially very high thermodynamic efficiency factors. The focus of this volume of Advances in Chemical Engineering is on quantitative approaches, particularly based on chemical engineering principles, to analyze, control and optimize the steady state and dynamic behavior of low and high temperature fuel cells (PEMFC, DMFC, SOFC) to be applied in mobile and stationary systems. * Updates and informs the reader on the latest research findings using original reviews * Written by leading industry experts and scholars * Review

  11. Vapor Delivery Systems for the Study of the Effects of Reformate Gas Impurities in HT-PEM Fuel Cells

    DEFF Research Database (Denmark)

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

    2011-01-01

    on a pump and electrically heated evaporator was found to be more suitable for the typical flow rates involved in the anode feed of an H3PO4/PBI based HT-PEMFC unit cell assembly. Test stations composed of vapor delivery systems and mass flow controllers for testing the effects of methanol slip...

  12. Fuel Cell Research at the University of South Carolina

    Energy Technology Data Exchange (ETDEWEB)

    Van Zee, John W.

    2006-09-25

    Five projects were conducted in an effort to supplement the efforts of fuel cell research at the University of South Carolina and to contribute to the Technical Plan for Fuel Cells of the Department of Energy. These efforts include significant interaction with the industrial community through DOE funded projects and through the National Science Foundation�s Industry/University Cooperative Research Center (NSF-I/UCRC) for Fuel Cells at USC. The allocation of projects described below leveraged all of these sources of funding without overlap and redundancy. 1. "Novel Non-Precious Metal Catalyst For PEMFCs" (Dr. Branko Popov) 2. "Non Carbon Supported Catalysts" (Dr. John Weidner) 3. "Hydrogen Quality" (Dr. Jean St-Pierre) 4. "Gasket Materials: Mechanical and Chemical Stability in PEMFC" (Dr. Y.J. (Bill) Chao) 5. "Mathematical Modeling of PEM Fuel Cells," (Dr. Sirivatch (Vatch) Shimpalee)

  13. Barriers to the development of fuel-cell electric vehicles

    International Nuclear Information System (INIS)

    The study is structured as follows: Fuel cells (with focus on proton exchange membrane fuel cells (PEMFC)); Fuel cell electric vehicles; Barriers to commercial use of fuel cell vehicles in the following areas: price; hydrogen production; hydrogen infrastructure; hydrogen storage; other barriers (safety; lifetime; use in extreme conditions; control system errors). The major barriers include too high price and problems with a stable and sustainable hydrogen source. Also, the following must be ensured for a wider use of FCEVs: reduction in the weight and volume of the drive unit; improved lifetime of the PEMFC system; usability within wide weather conditions; existence of an adequate infrastructure (a dense hydrogen service station network and their hydrogen supply); and implementation of related legislation including safety standards. (P.A.)

  14. 冷冻-解冻循环及气体吹扫对质子交换膜燃料电池的影响%Effects of Freeze/Thaw Cycles and Gas Purging Method on Polymer Electrolyte Membrane Fuel Cells

    Institute of Scientific and Technical Information of China (English)

    张生生; 俞红梅; 朱红; 侯俊波; 衣宝廉; 明平文

    2006-01-01

    At subzero temperature, the startup capability and performance of polymer electrolyte membrane fuel cell (PEMFC) deteriorates markedly. The object of this work is to study the degradation mechanism of key components of PEMFC-membrane-electrode assembly (MEA) and seek feasible measures to avoid degradation. The effect of freeze/thaw cycles on the structure of MEA is investigated based on porosity and SEM measurement. The performance of a single cell was also tested before and after repetitious freeze/thaw cycles. The experimental results indicated that the performance of a PEMFC decreased along with the total operating time as well as the pore size distribution shifting and micro configuration changing. However, when the redundant water had been removed by gas purging, the performance of the PEMFC stack was almost resumed when it experienced again the same subzero temperature test. These results show that it is necessary to remove the water in PEMFCs to maintain stable performance under subzero temperature and gas purging is proved to be the effective operation.

  15. Performance of miniaturized direct methanol fuel cell (DMFC) devices using micropump for fuel delivery

    Science.gov (United States)

    Zhang, Tao; Wang, Qing-Ming

    A fuel cell is a device that can convert chemical energy into electricity directly. Among various types of fuel cells, both polymer electrolyte membrane fuel cells (PEMFCs) and direct methanol fuel cells (DMFCs) can work at low temperature (mini pumps, the size of the piezoelectric micropump is much smaller and the energy consumption is much lower. Thus, it is very viable and effective to use a piezoelectric valveless micropump for fuel delivery in miniaturized DMFC power systems.

  16. 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...

  17. Desenvolvimento Sócio-Afectivo em Educação Física

    OpenAIRE

    Rosado, António

    1998-01-01

    A educação mantém, por finalidade, facilitar o desenvolvimento sócio-afectivo das novas gerações, o sentido de contribuir para que o processo de socialização dos jovens se processe num contexto de desenvolvimento de atitudes, de valores e de comportamentos sociais ajustados. Um dos objectivos fundamentais da Educação Física, partilhado, aliás, com as outras disciplinas curriculares, é o da facilitação do desenvolvimento sócio-afectivo, do desenvolvimento pessoal e social. Os programas naciona...

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

    Science.gov (United States)

    Hitchcock, A. P.; Lee, V.; Wu, J.; West, M. M.; Cooper, G.; 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.

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

    Energy Technology Data Exchange (ETDEWEB)

    Hitchcock, A. P., E-mail: aph@mcmaster.ca; Lee, V.; Wu, J.; Cooper, G. [Chemistry & Chemical Biology, McMaster University, Hamilton, ON, L8S 4M1 (Canada); West, M. M.; Berejnov, V. [Faculty of Health Sciences Electron Microscopy, McMaster University, Hamilton, ON L8N 3Z5 (Canada); Soboleva, T.; Susac, D.; Stumper, J. [Automotive Fuel Cell Cooperation Corp., Burnaby BC V5J 5J8 (Canada)

    2016-01-28

    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.

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

    International Nuclear Information System (INIS)

    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

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

    International Nuclear Information System (INIS)

    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 m2 commercial greenhouse during a year, respectively

  2. 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...

  3. HANARO Neutron Radiography Facility and Fuel Cell Research

    International Nuclear Information System (INIS)

    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 CO2. 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 (350Χ450mm2) and relatively high neutron flux (2Χ107 n/cm2sec), 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

  4. HANARO Neutron Radiography Facility and Fuel Cell Research

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Taejoo [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2013-07-01

    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{sub 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{sup 2}) and relatively high neutron flux (2Χ107 n/cm{sup 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.

  5. 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

  6. INVESTIGATION OF PEM FUEL CELL FOR AUTOMOTIVE USE

    OpenAIRE

    A K M Mohiuddin; Ataur Rahman; Mohamed Fadhil Chemani; Mohd Baihaqi Zakaria

    2015-01-01

    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...

  7. 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

    OpenAIRE

    Thiago Lopes; Ernesto R. Gonzalez

    2008-01-01

    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...

  8. 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.

  9. 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.

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

    International Nuclear Information System (INIS)

    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

  11. o desenvolvimento de novas alternativas terapêuticas

    OpenAIRE

    Barros, Eva Emanuela Soares da Silva

    2013-01-01

    Projeto de Pós-Graduação/Dissertação apresentado à Universidade Fernando Pessoa como parte dos requisitos para obtenção do grau de Mestre em Ciências Farmacêuticas A aplicação da nanotecnologia à medicina permitiu o desenvolvimento de sistemas inovadores transportadores de substância ativas à escala nanométrica, esta que oferece propriedades adicionais às de tamanho vulgar. O cancro é mundialmente determinante na mortalidade. As terapias convencionais conseguiram uma ligeira dimin...

  12. Desenvolvimento, Subdesenvolvimento e Democracia em África

    OpenAIRE

    Branco, Manuel

    2009-01-01

    Apesar da democratização constituir um processo eminentemente político, inúmeros estudos promovidos tanto por economistas como cientistas políticos, desde meados do século vinte, estabeleceram uma relação entre o nível de desenvolvimento e o carácter democrático da governação. O objectivo deste artigo é o de verificar esta hipótese para o continente africano, e mais propriamente para a sua fatia subsaariana. Ora, em contraste com os estudos supracitados, a literatura mais actual não permite c...

  13. Turismo e desenvolvimento regional: atrativos turísticos

    OpenAIRE

    Santos, Moacir José; Hanaoka, Fernando

    2015-01-01

    O presente artigo tem como objetivo apresentar caracterizar a Microrregião de Bananal a partir da identificação dos seus atrativos na Estrada Real - Caminho Novo da Piedade, nos municípios de Areias e Bananal dentro do território denominado como Vale Histórico, para apontar ações realizadas ou que possam vir a ser para o desenvolvimento daquele local, contemplando essencialmente a preservação de elementos históricos compatibilizados com o meio-ambiente urbano e a atividade turística contempor...

  14. Desenvolvimento ao "sabor" do turismo? : o caso Serra da Estrela

    OpenAIRE

    Vieira, Catarina Isabel da Cruz

    2008-01-01

    O presente estudo parte da ainda recente mudança de paradigma associada à forma como o espaço rural é encarado, reflectida na passagem de uma função de mero produtor de alimentos a espaço multifuncional, com responsabilidades no equilíbrio ecológico global e uma nova utilidade enquanto lugar de recreio e lazer. Adopta como quadro conceptual orientador, as correspondentes transformações nas abordagens teóricas e políticas de desenvolvimento rural, que, reconhecendo-lhe uma no...

  15. Desenvolvimento de novos produtos vinagreiros com Physalis peruviana

    OpenAIRE

    Vaz, Joana Filipa Pereira dos Santos

    2015-01-01

    Dissertação de mestrado em Tecnologia Alimentar, apresentada na Escola Superior Agrária de Santarém, Instituto Politécnico de Santarém. Este trabalho visa o desenvolvimento de novos produtos vinagreiros, inserido no projecto UIIPS/ESAS Tecnologia Vinagreira, sendo destinado a criar produtos alimentares com a inclusão de vinagre, podendo estes ter interesse para o mercado gourmet. Pretendeu-se contribuir para a diversificação da oferta. Articulando ensaios tecnológicos, laboratoriais, senso...

  16. Desenvolvimento territorial rural no Brasil: limites e potencialidades dos CONSADs

    OpenAIRE

    Antonio César Ortega

    2007-01-01

    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 c...

  17. Desenvolvimento de um indicador de melhoria contínua

    OpenAIRE

    Semião, Rui Miguel Santos Coelho

    2008-01-01

    O presente relatório resulta do desenvolvimento de um projecto de estágio efectuado, ao longo de nove meses, na empresa Bosch Termotecnologia SA. O objectivo deste trabalho é a definição da forma de cálculo de um indicador, que permitirá avaliar a frequência com que é produzido um grupo específico de produtos da empresa. O cálculo periódico deste indicador e, consequentemente, o seu acompanhamento irão permitir uma maior transparência no processo de planeamento de produção, ...

  18. Effects of passive films on corrosion resistance of uncoated SS316L bipolar plates for proton exchange membrane fuel cell application

    International Nuclear Information System (INIS)

    Highlights: • The passive film formed at PEMFC anode side shows a single layer structure. • The passive film formed at PEMFC cathode side shows a bi-layer structure. • The Cr/Fe atomic ratios in passive films formed at different side are different. • The passive films behave as n-type semiconductor at both anode and cathode sides. • The anode/cathode potential is positive than the flatband potential of passive film. - Abstract: The effects of passive films on the corrosion behaviors of uncoated SS316L in anode and cathode environments of proton exchange membrane fuel cells (PEMFCs) are studied. Potentiodynamic and potentiostatic polarizations are employed to study the corrosion behavior; Mott-Schottky measurements are used to characterize the semiconductor properties of passive films; X-ray photoelectron spectroscopy (XPS) analyses are used to identify the compositions and the depth profiles of passive films. The passive films formed in the PEMFC anode and cathode environments under corresponding conditions both behave as n-type semiconductor. The passive film formed in the anode environment has a single-layer structure, Cr is the major element (Cr/Fe atomic ratio > 1), and the Cr/Fe atomic ratio decreases from the surface to the bulk; while the passive film formed in the PEMFC cathode environment has a bi-layer structure, Fe is the major element (Cr/Fe atomic ratio < 0.5), and in the external layer of the bi-layer structure Fe content increases rapidly and gradually in the internal layer. SS316L shows better corrosion resistance owing to both the high content of Cr oxide in the passive film and low band bending in normal PEMFC anode environments

  19. Thin film thermocouples for in situ membrane electrode assembly temperature measurements in a polybenzimidazole-based high temperature proton exchange membrane unit cell

    DEFF Research Database (Denmark)

    Ali, Syed Talat; Lebæk, Jesper; Nielsen, Lars Pleth;

    2010-01-01

    This paper presents Type-T thin film thermocouples (TFTCs) fabricated on Kapton (polyimide) substrate for measuring the internal temperature of PBI(polybenzimidazole)-based high temperature proton exchange membrane fuel cell (HT-PEMFC). Magnetron sputtering technique was employed to deposit a 2 mu...

  20. Modelling and essay or the polarization curve of a polymeric membrane fuel cell; Modelagem e ensaio da curva de polarizacao de uma celula a combustivel de membrana polimerica

    Energy Technology Data Exchange (ETDEWEB)

    Almeida, Silvio Carlos Anibal de; Xavier, Bruno Domont; Gatti, George Cassani; Ribeiro, Rodrigo Minguita [Universidade Federal do Rio de Janeiro (UFRJ), RJ (Brazil). Coordenacao dos Programas de Pos-graduacao de Engenharia (COPPE). Programa de Engenharia Mecanica]. E-mails: silvioa@gmail.com; brunodomont@gmail.com; gatti_ufrj@yahoo.com.br; rminguita@yahoo.com.br; Furtado, Jose Geraldo de Melo [Centro de Pesquisas de Energia Eletrica (CEPEL), Rio de Janeiro, RJ (Brazil). Dept. de Tecnologias Especiais]. E-mail: furtado@cepel.br

    2006-07-01

    This paper describes the essays performed with a polymeric membrane fuel cell (PEMFC) at the test laboratories of the ELETROBRAS Electric Energy Research Center (CEPEL/ELETROBRAS) manufactured by the Eletrocell, which allows to study the influence of some functional parameters (voltage, current, mass and pressure fluxes)

  1. Phénomènes locaux instationnaires dans les piles à combustible à membrane (PEMFC) fonctionnant en mode bouché (dead-end)

    OpenAIRE

    ABBOU, Sofyane

    2015-01-01

    Cette thèse concerne les phénomènes locaux qui se produisent dans une pile à combustible à membrane (PEMFC) fonctionnant en mode bouché. Ce mode de fonctionnement consiste à alimenter l’anode en hydrogène sec tout en maintenant sa sortie fermée ce qui favorise l’accumulation d’eau et d’azote (issus du compartiment cathodique) près de la sortie anodique. Certaines régions sont donc convenablement alimentées en gaz tandis que d’autres ne le sont plus. Ces déséquilibres s’accompagnent de hausses...

  2. Impact of power converter current ripple on the durability of a fuel cell stack

    OpenAIRE

    WAHDAME, B; GIRARDOT, L; Hissel, D.; Harel, F.; Francois, X.; Candusso, D.; PERA, MC; DUMERCY, L

    2008-01-01

    The durability and performance of Polymer Electrolyte Membrane Fuel Cell (PEMFC) have a major impact on the most important challenges facing fuel cell commercialization including final cost, mass production, system integration, functionality and reliability. This work is supported by French Government via an ANR' project (PAN'H) named SPACT80. The global objective is to develop and validate the use of a fuel cell based power system for heavy-duty vehicles (dedicated to railway applications or...

  3. Polymer electrolyte membrane degradation and mobility in fuel cells : a solid-state NMR investigation

    OpenAIRE

    Ghassemzadeh Khoshkroodi, Lida

    2010-01-01

    It is generally believed that fuel cells will play an important role in energy technology already in the near future. Operating polymer electrolyte membrane fuel cells (PEMFCs) at temperatures higher than 100 °C and reduced humidity is anticipated to avoid most of the shortcomings associated with the low-temperature fuel cell operation, such as CO poisoning of the electrode catalysts, slow electrode kinetics of the oxygen reduction reaction and expensive water/thermal management. To date, the...

  4. 燃料电池及其相关材料新进展(三)%Novel Advances in Fuel Cells and Their Relevant Materials

    Institute of Scientific and Technical Information of China (English)

    杨遇春

    1999-01-01

    Fuel cells as a high efficient, non-polluting electricity generation system are already at a near-commercial or sub-commercial stage. To meet the need for the revolution of electricity industry based fuel cells within the next few years, principal types of fuel cell systems (phosphoric acid fuel cell - PAFC, proton exchange membrane fuel cell - PEMFC, Molten carbonate fuel cell - MCFC, Solid oxide fuel cell - SOFC), their development status and economic significance were introduced. Materials and their performance requirements in fuel cell development and current status and problems in material technologies were described also. It is suggested that the domestic development goal concerning fuel cells is direct at the development of SOFC and PEMFC incorporating the superionrity of our mineral resources.

  5. Effect of induced cross flow on flow pattern and performance of proton exchange membrane fuel cell

    International Nuclear Information System (INIS)

    Highlights: • 3D numerical works to study the effect of cross flow on the PEMFC performance. • The cross flow ensure more evenly distributed water and oxygen in the CL. • The optimal net power output can be identified by controlling the back pressure. • Results confirm that present design is effective in improving performance. - Abstract: The cross flow in proton exchange membrane fuel cells (PEMFCs) plays an important role in changing the transport pattern and performance. In this study, three-dimensional numerical simulations are carried out to investigate the effect of induced cross flow on the flow pattern and performance of a PEMFC with a previously proposed and experimentally studied novel parallel flow channel design. The numerical results indicate that the liquid water and oxygen become more evenly distributed in the catalyst layer (CL) as the pressure difference between the low-pressure and high-pressure flow channels increases. It has been found that, in the low-pressure channels, the cross flow drives a convective flow from the CL to the flow channel resulting in improved liquid water removal. The optimal net power output can be identified by controlling the back pressure on the high-pressure flow channels. The numerical results confirm that this novel parallel flow channel design is effective in improving PEMFC performance

  6. Studies of bibenzimidazole and imidazole influence on electrochemical properties of polymer fuel cells

    International Nuclear Information System (INIS)

    Binary and ternary membranes were prepared by immersion of Nafion-115 in 2,2′-bis(4-aminophenyl)-5,5′-bibenzimidazole (BAPBI) or/and in imidazole (Im) and were used in proton exchange membrane fuel cells (PEMFCs) with Pt/C gas diffusion electrodes and graphite single-serpentine monopolar plates. Membranes were activated in 0.2 M H2SO4. BAPBI was synthesized in poly(phosphoric) acid and the chemical structure was confirmed by 1H, 13C NMR and ATR-FTIR spectroscopy. Membranes were characterized by FTIR spectroscopy, TGA, AFM techniques. Also the water uptake was determined. PEMFCs were investigated by electrochemical impedance spectroscopy, polarization curves, cyclic voltammetry and linear sweep voltammetry taking into consideration the kind of imidazole applied and the temperature used (25 or 60 °C). The maximum power density of 146 mW/cm2 at the current density of 345 mA/cm2 was detected for Nafion-115-BAPBI membrane. For all constructed PEMFCs the efficiency at 0.6 V was found about 41%. The immersion of Nafion-115 in Im, BAPBI or BAPBI-Im increased the thermal stability and mechanical properties of membranes. The Nafion-115-BAPBI membrane showed good prospective for application in PEMFCs while in opposite to Nafion-115-Im, the poisoning effect on Pt catalyst was not observed

  7. 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)

  8. 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.

  9. Performance and degradation of Proton Exchange Membrane Fuel Cells: State of the art in modeling from atomistic to system scale

    Science.gov (United States)

    Jahnke, T.; Futter, G.; Latz, A.; Malkow, T.; Papakonstantinou, G.; Tsotridis, G.; Schott, P.; Gérard, M.; Quinaud, M.; Quiroga, M.; Franco, A. A.; Malek, K.; Calle-Vallejo, F.; Ferreira de Morais, R.; Kerber, T.; Sautet, P.; Loffreda, D.; Strahl, S.; Serra, M.; Polverino, P.; Pianese, C.; Mayur, M.; Bessler, W. G.; Kompis, C.

    2016-02-01

    Proton Exchange Membrane Fuel Cells (PEMFC) are energy efficient and environmentally friendly alternatives to conventional energy conversion systems in many yet emerging applications. In order to enable prediction of their performance and durability, it is crucial to gain a deeper understanding of the relevant operation phenomena, e.g., electrochemistry, transport phenomena, thermodynamics as well as the mechanisms leading to the degradation of cell components. Achieving the goal of providing predictive tools to model PEMFC performance, durability and degradation is a challenging task requiring the development of detailed and realistic models reaching from the atomic/molecular scale over the meso scale of structures and materials up to components, stack and system level. In addition an appropriate way of coupling the different scales is required. This review provides a comprehensive overview of the state of the art in modeling of PEMFC, covering all relevant scales from atomistic up to system level as well as the coupling between these scales. Furthermore, it focuses on the modeling of PEMFC degradation mechanisms and on the coupling between performance and degradation models.

  10. Desenvolvimento de produtos usando a abordagem MCDA-C

    Directory of Open Access Journals (Sweden)

    Tiago Pereira Santos de Oliveira Machado

    2015-09-01

    Full Text Available O objetivo do presente trabalho consiste em construir um modelo para auxiliar a gestão do desenvolvimento de produtos de uma empresa de eletrodomésticos. Trata-se de um estudo de caso, exploratório e de natureza prática, que segue uma abordagem quali-quantitativa. Os dados para estruturação do problema foram coletados diretamente com o gestor do departamento de cocção e em documentos internos da empresa. O instrumento de intervenção utilizado foi a Abordagem Multicritério de Apoio à Decisão Construtivista (MCDA-C, que permitiu ao gestor desse contexto visualizar os critérios que devem ser considerados em um processo de avaliação de fogões, bem como permitiu a mensuração ordinal e cardinal do desempenho dos fogões de mesa, auxiliando assim nas decisões de elaboração de projetos de desenvolvimento e aprimoramento desses produtos. Para facilitar o entendimento deste artigo, os autores optaram por dar foco a um dos critérios do modelo: a usabilidade.

  11. A mathematical model to study the performance of a proton exchange membrane fuel cell in a dead-ended anode mode

    International Nuclear Information System (INIS)

    Highlights: • This model can predict the performance of a single cell in a dead-ended anode mode. • The hypothesis of how current density affects nitrogen accumulation is proposed. • The model was calibrated and validated by experiments. • Nitrogen concentration is regarded as a parameter for anode purge strategy. - Abstract: When a proton exchange membrane fuel cell (PEMFC) system is operated in the dead-ended anode mode, nitrogen will gradually permeate from the cathode to the anode. The accumulation of nitrogen in the anode causes a performance drop, which can be recovered by purging. The purge strategy depends on operating conditions of the PEMFC. To investigate the effect of operating conditions on the performance of a PEMFC with a dead-ended anode, a mathematical model is developed to estimate the nitrogen crossover and accumulation in the anode of the PEMFC, especially for varying-load operations. The effect of operating current density on nitrogen crossover is coupled in the model. Parameters in the model are calibrated according to experimental data. The experiments are designed to measure the voltage variations of the single cell with dead-ended anode at different operating current densities. The effect of current density on purge frequency and voltage variation is shown. Simulation results by this calibrated model agree well with experimental data. The transient of hydrogen concentration in the anode is investigated by the model. A purge strategy is suggested at the end of this study

  12. 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.

  13. 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)

  14. Proton exchange membrane fuel cells cold startup global strategy for fuel cell plug-in hybrid electric vehicle

    Science.gov (United States)

    Henao, Nilson; Kelouwani, Sousso; Agbossou, Kodjo; Dubé, Yves

    2012-12-01

    This paper investigates the Proton Exchange Membrane Fuel Cell (PEMFC) Cold Startup problem within the specific context of the Plugin Hybrid Electric Vehicles (PHEV). A global strategy which aims at providing an efficient method to minimize the energy consumption during the startup of a PEMFC is proposed. The overall control system is based on a supervisory architecture in which the Energy Management System (EMS) plays the role of the power flow supervisor. The EMS estimates in advance, the time to start the fuel cell (FC) based upon the battery energy usage during the trip. Given this estimation and the amount of additional energy required, the fuel cell temperature management strategy computes the most appropriate time to start heating the stack in order to reduce heat loss through the natural convection. As the cell temperature rises, the PEMFC is started and the reaction heat is used as a self-heating power source to further increase the stack temperature. A time optimal self-heating approach based on the Pontryagin minimum principle is proposed and tested. The experimental results have shown that the proposed approach is efficient and can be implemented in real-time on FC-PHEVs.

  15. Improved Performance of Sulfonated Polyarylene Ethers for Proton Exchange Membrane Fuel Cell

    Institute of Scientific and Technical Information of China (English)

    D. Xing; J. Kerres; F. Sch(o)nberger

    2005-01-01

    @@ 1Introduction The proton exchange membrane (PEM) is one of key components in fuel cell system. Its properties are very important in determining PEMFC performance. The membranes presently used in fuel cell are perfluorosulfonic polymers, such as Nafion(R) from Dupont. Although they have high proton conductivity and excellent chemical stability, their too high production cast and methanol permeability lead to failure of fuel cell application. Therefore, various partially fluorinated and non-fluorinated polymer electrolytes are under development for PEMFC application since one decade. In the middle of non-fluorinated polymer electrolytes, sulfonated poly(arylene ether)s display high thermal stability, good mechanical properties and exceptional resistance to oxidation and acid catalyzed hydrolysis. They have been regarded as well-suited proton exchange membrane candidates for fuel cells.

  16. Performance prediction of a proton exchange membrane fuel cell using the ANFIS model

    Energy Technology Data Exchange (ETDEWEB)

    Vural, Yasemin; Ingham, Derek B.; Pourkashanian, Mohamed [Centre for Computational Fluid Dynamics, University of Leeds, Houldsworth Building, LS2 9JT Leeds (United Kingdom)

    2009-11-15

    In this study, the performance (current-voltage curve) prediction of a Proton Exchange Membrane Fuel Cell (PEMFC) is performed for different operational conditions using an Adaptive Neuro-Fuzzy Inference System (ANFIS). First, ANFIS is trained with a set of input and output data. The trained model is then tested with an independent set of experimental data. The trained and tested model is then used to predict the performance curve of the PEMFC under various operational conditions. The model shows very good agreement with the experimental data and this indicates that ANFIS is capable of predicting fuel cell performance (in terms of cell voltage) with a high accuracy in an easy, rapid and cost effective way for the case presented. Finally, the capabilities and the limitations of the model for the application in fuel cells have been discussed. (author)

  17. Platinum redispersion on metal oxides in low temperature fuel cells

    DEFF Research Database (Denmark)

    Tripkovic, Vladimir; Cerri, Isotta; Nagami, Tetsuo; Bligaard, Thomas; Rossmeisl, Jan

    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...

  18. Optimal design and operational tests of a high-temperature PEM fuel cell for a combined heat and power unit

    OpenAIRE

    Barreras Toledo, Felix Manuel; Lozano Fantoba, Antonio; Roda Serrat, Vicente; Barroso Estébanez, Jorge Angel; Martin Yagüe, Jesus Joaquín

    2014-01-01

    Development of new materials for polymer electrolyte membranes has allowed increasing the operational temperature of PEM fuel cell stacks above 120 degrees C. The present paper summarizes the main results obtained in a research devoted to the design, fabrication and operational tests performed on a high-temperature PEMFC prototype. A 5-cell stack has been assembled with commercial Celtec P-1000 high-temperature MEAs from BASF Fuel Cells, but the rest of elements and processes have been develo...

  19. 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.

  20. Using qualimetric engineering and extremal analysis to optimize a proton exchange membrane fuel cell stack

    International Nuclear Information System (INIS)

    Highlights: • We consider the optimal configuration of a PEMFC stack. • We utilize qualimetric engineering tools (Taguchi screening, regression analysis). • We achieve analytical solution on a restructured power-law fitting. • We discuss the Pt-cost involvement in the unit and area minimization scope. - Abstract: The optimal configuration of the proton exchange membrane fuel-cell (PEMFC) stack has received attention recently because of its potential use as an isolated energy distributor for household needs. In this work, the original complex problem for generating an optimal PEMFC stack based on the number of cell units connected in series and parallel arrangements as well as on the cell area is revisited. A qualimetric engineering strategy is formulated which is based on quick profiling the PEMFC stack voltage response. Stochastic screening is initiated by employing an L9(33) Taguchi-type OA for partitioning numerically the deterministic expression of the output PEMFC stack voltage such that to facilitate the sizing of the magnitude of the individual effects. The power and current household specifications for the stack system are maintained at the typical settings of 200 W at 12 V, respectively. The minimization of the stack total-area requirement becomes explicit in this work. The relationship of cell voltage against cell area is cast into a power-law model by regression fitting that achieves a coefficient of determination value of 99.99%. Thus, the theoretical formulation simplifies into a non-linear extremal problem with a constrained solution due to a singularity which is solved analytically. The optimal solution requires 22 cell units connected in series where each unit is designed with an area value of 151.4 cm2. It is also demonstrated how to visualize the optimal solution using the graphical method of operating lines. The total area of 3270.24 cm2 becomes a new benchmark for the optimal design of the studied PEMFC stack configuration. It is

  1. ASPECTOS PECULIARES DO DESENVOLVIMENTO DO TIMO EM SUÍNOS

    OpenAIRE

    Mariana Sincai; Adrian Marcu

    1994-01-01

    RESUMO O desenvolvimento morfometabólico do timo foi estudado na ontogenia pré e pós-natal em suínos. Os estudos indicam que o timo já está organizado muito cedo durante o período pré-natal, por volta dos dois meses de prenhez. Os estudos histoquímicos indicam uma intensa atividade secretora das células reticuloepiteliais e também dos corpúsculos tímicos. Os estudos histológicos no período pré-natal revelaram uma presença maciça de corpúsculos tímicos e a existência de algumas células mióides...

  2. A água, género e desenvolvimento

    OpenAIRE

    Campos, Alexandra de

    2011-01-01

    A água é um recurso natural renovável, imprescindível ao Homem para as suas actividades enquanto ser vivo. Da água depende a vida humana, a segurança alimentar e a manutenção dos ecossistemas. A água deve ser reconhecida não só como um bem económico, como também um bem social. A água é vital para a diminuição da pobreza e para o desenvolvimento sustentável. A questão do género é uma questão de poder. As categorias em função do sexo “homens” e “mulheres” não são homogéneas. Em países em ...

  3. 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.

  4. 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

  5. Dynamic Behavior of a Proton Exchange Membrane Fuel Cell under Transportation Cycle Load

    OpenAIRE

    Garnier, J.; PERA, MC; Hissel, D.; DE-BERNARDINIS, A; KAUFFMANN, JM; Coquery, G.

    2004-01-01

    This paper presents a dynamic modeling of a proton exchange membrane fuel cell (PEMFC) for transportation applications. Based on an electrochemical analysis, it gives an equivalent circuit of the fuel cell which can be used in association with a power electronic converter. Experimental polarization curves and electrochemical impedance spectroscopy (EIS) are used to identify model parameters and to validate simulation results. Finally, experimental responses to a current step and to transporta...

  6. The use of additive manufacture for metallic bipolar plates in polymer electrolyte fuel cell stacks

    OpenAIRE

    Dawson, Richard; Patel, Anant; Rennie, Allan; White, Simon

    2014-01-01

    The bipolar plate is of critical importance to the efficient and long lasting operation of a polymer electrolyte fuel cell (PEMFC) stack. With advances in membrane electrode assembly (MEA) design greater attention has been focused on the bipolar plate and the important role it plays in performance and durability. Although carbon composite plates are a likely candidate for the mass introduction of fuel cells, it is metallic plates made from thin strip materials (typically 0.2 mm thick stainles...

  7. Continual Energy Management System of Proton Exchange Membrane Fuel Cell Hybrid Power Electric Vehicles

    OpenAIRE

    Ren Yuan; Zhong Zhi Dan; Zhang Zhi Wen; Luo Tian Yu

    2016-01-01

    Current research status in energy management of Proton Exchange Membrane (PEM) fuel cell hybrid power electric vehicles are first described in this paper, and then build the PEMFC/ lithium-ion battery/ ultra-capacitor hybrid system model. The paper analysis the key factors of the continuous power available in PEM fuel cell hybrid power electric vehicle and hybrid power system working status under different driving modes. In the end this paper gives the working flow chart of the hybrid power s...

  8. Transferências de Renda para o Desenvolvimento Humano a Longo Prazo

    OpenAIRE

    Armando Barrientos

    2013-01-01

    Com a notável expansão dos programas de transferência de renda no combate à pobreza em países em desenvolvimento na última década, os programas de transferência de renda para o desenvolvimento humano, popularmente conhecidos como transferências condicionadas de renda, vêm desempenhado um papel notável. Sua característica principal combina as transferências de renda às famílias pobres com medidas para facilitar o investimento no desenvolvimento humano, especialmente para as crianças. Desde sua...

  9. Turismo e Desenvolvimento Humano na Província de Inhambane

    OpenAIRE

    Xavier, Kátia Sara Henriques

    2010-01-01

    Mestrado em Desenvolvimento e Cooperação Internacional Nos anos 50/60 começou a dar-se particular atenção tanto na Europa como nos EUA e Austrália ao turismo enquanto oportunidade para o desenvolvimento económico. Com efeito, de acordo com a World Tourism Organisation (WTO) esta actividade tem um papel crucial na luta contra a pobreza nos países de baixa renda. Um dos desafios do novo milénio para os países pobres é o desenvolvimento económico e social. De acordo com Thirlwall (2002), u...

  10. O desenvolvimento do sistema venoso cerebral - do embrião à estrutura definitiva no adulto

    OpenAIRE

    Lopes, L.; Palma, T.; Cravo, I; C. Gonçalves; Bousende, M; Pisco, J

    2012-01-01

    Introdução: O desenvolvimento humano consiste num processo contínuo, extremamente complexo com repetidos ciclos de cresci- mento, modulação e modificação. Apesar da intrincada complexidade, o normal desenvolvimento caracteriza-se por uma impression - ante regularidade. Regularidade essa que se traduz em múltiplas vertentes, designadamente, cronológica, anatómica, topográfica e fisiológica. Por vezes, este desenvolvimento não se encontra totalmente finalizado por altura do parto, doc...

  11. 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.

  12. Alkaline polymer electrolyte fuel cells: Principle, challenges, and recent progress

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    Polymer electrolyte membrane fuel cells (PEMFC) have been recognized as a significant power source in future energy systems based on hydrogen. The current PEMFC technology features the employment of acidic polymer electrolytes which, albeit superior to electrolyte solutions, have intrinsically limited the catalysts to noble metals, fundamentally preventing PEMFC from widespread deployment. An effective solution to this problem is to develop fuel cells based on alkaline polymer electrolytes (APEFC), which not only enable the use of non-precious metal catalysts but also avoid the carbonate-precipitate issue which has been troubling the conventional alkaline fuel cells (AFC). This feature article introduces the principle of APEFC, the challenges, and our research progress, and focuses on strategies for developing key materials, including high-performance alkaline polyelectrolytes and stable non-precious metal catalysts. For alkaline polymer electrolytes, high ionic conductivity and satisfactory mechanical property are difficult to be balanced, therefore polymer cross-linking is an ultimate strategy. For non-precious metal catalysts, it is urgent to improve the catalytic activity and stability. New materials, such as transition-metal complexes, nitrogen-doped carbon nanotubes, and metal carbides, would become applicable in APEFC.

  13. Durability and performance optimization of cathode materials for fuel cells

    Science.gov (United States)

    Colon-Mercado, Hector Rafael

    The primary objective of this dissertation is to develop an accelerated durability test (ADT) for the evaluation of cathode materials for fuel cells. The work has been divided in two main categories, namely high temperature fuel cells with emphasis on the Molten Carbonate Fuel Cell (MCFC) cathode current collector corrosion problems and low temperature fuel cells in particular Polymer Electrolyte Fuel Cell (PEMFC) cathode catalyst corrosion. The high operating temperature of MCFC has given it benefits over other fuel cells. These include higher efficiencies (>50%), faster electrode kinetics, etc. At 650°C, the theoretical open circuit voltage is established, providing low electrode overpotentials without requiring any noble metal catalysts and permitting high electrochemical efficiency. The waste heat is generated at sufficiently high temperatures to make it useful as a co-product. However, in order to commercialize the MCFC, a lifetime of 40,000 hours of operation must be achieved. The major limiting factor in the MCFC is the corrosion of cathode materials, which include cathode electrode and cathode current collector. In the first part of this dissertation the corrosion characteristics of bare, heat-treated and cobalt coated titanium alloys were studied using an ADT and compared with that of state of the art current collector material, SS 316. PEMFCs are the best choice for a wide range of portable, stationary and automotive applications because of their high power density and relatively low-temperature operation. However, a major impediment in the commercialization of the fuel cell technology is the cost involved due to the large amount of platinum electrocatalyst used in the cathode catalyst. In an effort to increase the power and decrease the cathode cost in polymer electrolyte fuel cell (PEMFC) systems, Pt-alloy catalysts were developed to increase its activity and stability. Extensive research has been conducted in the area of new alloy development and

  14. Small proton exchange membrane fuel cell power station by using bio-hydrogen

    Institute of Scientific and Technical Information of China (English)

    刘志祥; 毛宗强; 王诚; 任南琪

    2006-01-01

    In fermentative organic waste water treatment process, there was hydrogen as a by-product. After some purification,there was about 50% ~ 70% hydrogen in the bio-gas, which could be utilized for electricity generation with fuel cell. Half a year ago, joint experiments between biological hydrogen production in Harbin Institute of Technology (HIT) and proton exchange membrane fuel cell (PEMFC) power station in Tsinghua University were conducted for electricity generation with bio-hydrogen from the pilot plant in HIT. The results proved the feasibility of the bio-hydrogen as a by-product utilization with PEMFC power station and revealed some problems of fuel cell power station for this application.

  15. Dynamic neural network controller model of PEM fuel cell system

    Energy Technology Data Exchange (ETDEWEB)

    Hatti, Mustapha [Nuclear Technologies Division, Nuclear Research Center of Birine, Ain Oussera, B.P 180, 17200 Djelfa (Algeria); Tioursi, Mustapha [Electrical Engineering Department, University of Sciences and Technology of Oran, B.P 1505, El M' Naouar, 31000 Oran (Algeria)

    2009-06-15

    This paper presents the artificial intelligence techniques to control a proton exchange membrane fuel cell system process, using particularly a methodology of dynamic neural network. In this work a dynamic neural network control model is obtained by introducing a delay line in the input of the neural network. A static production system including a PEMFC is subjected to variations of active and reactive power. Therefore the goal is to make the system follow these imposed variations. The simulation requires the modelling of the principal element (PEMFC) in dynamic mode. The simulation results demonstrate that the model-based dynamic neural network control scheme is appropriate for controlling, the stability of the identification and the tracking error were analyzed, and some reasons for the usefulness of this methodology are given. (author)

  16. Um exame histórico-filosófico da biologia evolutiva do desenvolvimento

    OpenAIRE

    Ana Maria Rocha de Almeida; Charbel Niño El-Hani

    2010-01-01

    O desenvolvimento tem papel central na compreensão da evolução dos organismos multicelulares, dado que é o processo que resulta na produção da forma orgânica adulta. Logo, toda inovação morfológica deve ser também o resultado de modificações no desenvolvimento. Entretanto, a biologia do desenvolvimento permaneceu à margem da síntese evolutiva e o desenvolvimento foi tratado por muito tempo como uma caixa preta entre o genótipo e o fenótipo. Somente a partir dos anos 1980, foi dada mais atençã...

  17. Ambiente Visual para o Desenvolvimento de Jogos Eletrônicos

    Directory of Open Access Journals (Sweden)

    Diego Cordeiro Barboza

    2015-07-01

    Full Text Available Este artigo apresenta o desenvolvimento de um software para auxílio ao desenvolvimento de jogos eletrônicos, no qual é possível definir a lógica do jogo utilizando apenas componentes gráficos reutilizáveis, sem necessidade de codificação. O trabalho trata do desenvolvimento de um wrapper para a biblioteca gráfica utilizada, um framework para o desenvolvimento de jogos em geral e a ferramenta gráfica em si em conjunto com um gerador de código responsável por traduzir as ações do usuário em código-fonte em uma linguagem de programação.

  18. DANÇA E O DESENVOLVIMENTO MOTOR DE PORTADORES DE NECESSIDADES EDUCATIVAS ESPECIAIS - PNEEs

    Directory of Open Access Journals (Sweden)

    Liliane de Oliveira

    2012-04-01

    Full Text Available O estudo objetivou verificar as modificações nos padrões de desenvolvimento motor de PNEEs mediante prática da dança. Participaram 14 PNEEs do CIEP/Cruz Alta. O instrumento foi a Escala de Desenvolvimento Motor (Rosa Neto, 1996. Utilizou-se a estatística descritiva e teste “t” para análise dos dados. Observou-se diferenças estatisticamente significativas (p<0,05 entre pré e pós-testes nas variáveis idade cronológica, motora geral, motricidade ampla e equilíbrio. Concluiu-se que o programa de dança contribuiu significativamente para o desenvolvimento motor de PNEEs. Palavras chave: dança, motor, desenvolvimento, especial, educação.

  19. Coaching executivo enquanto prática de desenvolvimento intencional nas organizações

    OpenAIRE

    Nuno R dos Santos

    2011-01-01

    Apresentarei o coaching enquanto prática de intervenção nas organizações que visa o desenvolvimento das mesmas através do desenvolvimento dos executivos. Farei uma apresentação do estado da arte e das investigações que têm sido desenvolvidas em Portugal sobre o tema, quer na Universidade de Évora quer na Universidade de Coimbra.

  20. Use of Multi-Functional Flexible Micro-Sensors for in situ Measurement of Temperature, Voltage and Fuel Flow in a Proton Exchange Membrane Fuel Cell

    OpenAIRE

    Chung-Ju Lee; Pin-Cheng Chan; Chi-Yuan Lee

    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 cont...

  1. HIGH TEMPERATURE POLYMER FUEL CELLS

    DEFF Research Database (Denmark)

    Jensen, Jens Oluf; Qingfeng, Li; He, Ronghuan; Gang, Xiao; Gao, Ji-An; Bjerrum, Niels

    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...... temperature allows for utilization of the excess heat for fuel processing. Moreover, it provides an excellent CO tolerance of several percent, and the system needs no purification of hydrogen from a reformer. Continuous service for over 6 months at 150°C has been demonstrated....

  2. Desenvolvimento psicomotor em crianças com perturbações do espetro do autismo e desenvolvimento típico: um estudo comparativo

    OpenAIRE

    Fontes, Ana Catarina Moreira

    2013-01-01

    Avaliou-se o perfil psicomotor de 31 crianças, 12 com Autismo de Alto Funcionamento/ Síndrome de Asperger e 19 com Desenvolvimento Típico (DT), do género masculino, e com um QI >70, utilizando a Escala do Desenvolvimento Mental de Ruth Griffiths (Griffiths, 1984). Não foi definido um perfil específico do grupo com PEA, no entanto observaram-se diferenças significativas entre grupos, com superioridade no grupo com DT, exceto na área Pessoal-Social. Encontraram-se correlações positivas e estati...

  3. STATE OF PEMFC METAL BIPOLAR PLATE MATERIALS%质子交换膜燃料电池金属双极板材料研究进展

    Institute of Scientific and Technical Information of China (English)

    由宏新; 何广利; 丁信伟; 殷涛; 阿布里提·阿布都拉

    2003-01-01

    双极板在质子交换膜燃料电池(PEMFC)中具有隔离反应介质、收集电流、提供气体通道的作用,金属材料用于双极板面临腐蚀及表面层钝化影响电池性能等问题.在介绍了研究金属双极板性能的方法,包括接触电阻测试、电池极化性能测试、模拟电化学方法等测试方法的同时,着重介绍了在双极板中应用的不同种类铁基金属材料、轻金属材料的性能及各种表面涂层技术的研究进展.简单介绍了PEMFC中,金属双极板材料研究所应重点解决的技术问题.

  4. Evaluating focused ion beam and ultramicrotome sample preparation for analytical microscopies of the cathode layer of a polymer electrolyte membrane fuel cell

    Science.gov (United States)

    de A. Melo, Lis G.; Hitchcock, Adam P.; Berejnov, Viatcheslav; Susac, Darija; Stumper, Juergen; Botton, Gianluigi A.

    2016-04-01

    Optimizing the structure of the porous electrodes of polymer electrolyte membrane fuel cells (PEM-FC) can improve device power and durability. Analytical microscopy techniques are important tools for measuring the electrode structure, thereby providing guidance for structural optimization. Transmission Electron Microscopy (TEM), with either Energy Dispersive X-Ray (EDX) or Electron Energy Loss Spectroscopy (EELS) analysis, and Scanning Transmission X-Ray Microscopy (STXM) are complementary methods which, together, provide a powerful approach for PEM-FC electrode analysis. Both TEM and STXM require thin (50-200 nm) samples, which can be prepared either by Focused Ion Beam (FIB) milling or by embedding and ultramicrotomy. Here we compare TEM and STXM spectromicroscopy analysis of FIB and ultramicrotomy sample preparations of the same PEM-FC sample, with focus on how sample preparation affects the derived chemical composition and spatial distributions of carbon support and ionomer. The FIB lamella method, while avoiding pore-filling by embedding media, had significant problems. In particular, in the FIB sample the carbon support was extensively amorphized and the ionomer component suffered mass loss and structural damage. Although each sample preparation technique has a role to play in PEM-FC optimization studies, it is important to be aware of the limitations of each method.

  5. Effects of passive films on corrosion resistance of uncoated SS316L bipolar plates for proton exchange membrane fuel cell application

    Science.gov (United States)

    Yang, Ying; Ning, Xiaohui; Tang, Hongsheng; Guo, Liejin; Liu, Hongtan

    2014-11-01

    The effects of passive films on the corrosion behaviors of uncoated SS316L in anode and cathode environments of proton exchange membrane fuel cells (PEMFCs) are studied. Potentiodynamic and potentiostatic polarizations are employed to study the corrosion behavior; Mott-Schottky measurements are used to characterize the semiconductor properties of passive films; X-ray photoelectron spectroscopy (XPS) analyses are used to identify the compositions and the depth profiles of passive films. The passive films formed in the PEMFC anode and cathode environments under corresponding conditions both behave as n-type semiconductor. The passive film formed in the anode environment has a single-layer structure, Cr is the major element (Cr/Fe atomic ratio > 1), and the Cr/Fe atomic ratio decreases from the surface to the bulk; while the passive film formed in the PEMFC cathode environment has a bi-layer structure, Fe is the major element (Cr/Fe atomic ratio < 0.5), and in the external layer of the bi-layer structure Fe content increases rapidly and gradually in the internal layer. SS316L shows better corrosion resistance owing to both the high content of Cr oxide in the passive film and low band bending in normal PEMFC anode environments.

  6. 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

  7. DESENVOLVIMENTO DA EDUCAÇÃO AMBIENTAL NO CONTEXTO ESCOLAR

    Directory of Open Access Journals (Sweden)

    FILGUEIRA, Ana Maria Falcão

    2014-10-01

    Full Text Available Science and education are of great importance for the full understanding of a society facing environmental problems. Schools have a fundamental role in this relationship, since they contribute to the formation of individuals and also to the formation and development of values that provide students with the search for the search for knowledge and conducts them to the preservation of the environment. In this context, the purpose of this study was to acknowledge the Environmental Education as part of the school universe, not as a specific subject, but present through the interdisciplinarity. This present study brought forward some topics about its importance to the school context, the need of teachers’ enablement and the importance of developing environmental practices in the classroom. There was also a sequence of three activities with the students. The first activity consisted of a game about the ecosystem in the schoolyard. The second one involved researches in the computer room. The third one involved making posters about environmental awareness. After these activities, the data were analyzed in a qualitative way, besides observation and follow-up during the development of the activities. Working the environmental theme in the school context is fundamental to the formation of individuals, because it promotes a harmonious relationship with the environment and, thus, the schools must look for some means of developing different activities. However, they lack structural and pedagogical requirements. But these problems cannot still be the excuses for not doing them. A ciência e a educação são de grande importância para a compreensão da sociedade diante os problemas ambientais enfrentados. Nesse sentido, a escola tem papel fundamental, pois contribui para a formação do indivíduo e também para o desenvolvimento de valores que propiciem aos alunos a busca por novos conhecimentos e que os conduza para a preservação do meio ambiente. Dentro

  8. A Simulation Tool for Geometrical Analysis and Optimization of Fuel Cell Bipolar Plates: Development, Validation and Results

    OpenAIRE

    Javier Pino; Felipe Rosa; Alfredo Iranzo

    2009-01-01

    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 B...

  9. Experimental Study on a Voltage Source Inverter-fed Induction Motor Traction System Connected to Fuel Cell

    Science.gov (United States)

    Furuya, Takemasa; Kondo, Keiichiro; Yamamoto, Takamitsu

    This paper describes the experimental results of a test to drive two induction motors through a VVVF inverter by 25kW class proton membrane type fuel cells (PEMFCs). The experiments are aimed at verifying the compatibility between the drive system for the railway vehicle traction and FCs. This paper describes test results of powering, powering-off procedure, and simulated slip-readhesion control test, respectively. Through the experiments, we obtained useful knowledge required in designing the fuel cell drive system.

  10. 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. In tha...... mode at a hydrogen stoichiometric flow ratio as low as 1.03, the molar fraction of hydrogen in the gas mixture at the anode outlet is at least 50% which means that at steady state there will be no hydrogen starvation at the anode outlet.......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. In that...

  11. 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.

  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. Fabrication and Testing of a Bi-Conductive Polymer Membrane Fuel Cell

    Science.gov (United States)

    Hamel, S.; Tsukamoto, T.; Tanaka, T.; Fréchette, L. G.

    2014-11-01

    This paper reports the fabrication process and testing of a bi-conductive polymer membrane (BCPM) fuel cell that integrates lateral current collectors on both sides with an ionic conductive path through the membrane. The new membrane shows major advantages over standard Nafion® membranes used in Polymer Electrolyte Fuel Cells (PEMFCs). In addition to being mechanically stable when wet, the flexible BCPM integrates efficient thin film current collectors (ICCs) on an ionic conductive membrane with a high active area ratio. Also, ICCs leave all the surface of the electrode free to eventually integrate a more efficient water and gas management system than traditional gas diffusion layers. Moreover, the fabricated membrane has shown superior volumetric power density than standard PEMFC (0.76 vs 0.47 mW/cm2μm).

  14. SiC nanocrystals as Pt catalyst supports for fuel cell applications

    DEFF Research Database (Denmark)

    Dhiman, Rajnish; Morgen, Per; Skou, E.M.;

    2013-01-01

    A robust catalyst support is pivotal to Proton Exchange Membrane Fuel Cells (PEMFCs) to overcome challenges such as catalyst support corrosion, low catalyst utilization and overall capital cost. SiC is a promising candidate material which could be applied as a catalyst support in PEMFCs. SiC...... nanocrystals of SiC-SPR and SiC-NS by the polyol method. The SiC substrates are subjected to an acid treatment to introduce the surface groups, which help to anchor the Pt nano-catalysts. These SiC based catalysts have been found to have a higher electrochemical activity than commercially available Vulcan...... based catalysts (BASF & HISPEC). These promising results signal a new era of SiC based catalysts for fuel cell applications. © The Royal Society of Chemistry 2013....

  15. 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.

  16. Experimental Study of Polymer Electrolyte Membrane Fuel Cell Performance Under Low Operating Temperatures

    International Nuclear Information System (INIS)

    In this study, the performance characteristics of a polymer electrolyte membrane fuel cell (PEMFC) were investigated at low operating temperatures under steady-state and dynamic conditions. The performance of the PEMFC was analyzed according to the external humidifying rate and air stoichiometry. The ohmic resistance was also investigated using EIS tests. At the operating temperature of 35 ℃, voltage fluctuation occurred to a greater degree compared to that at 45 ℃. Therefore, it was found that the air stoichiometry should be higher than 2.5 for the stable operation of the fuel cell. In addition, the relative humidity of the reactant gases should be higher than 60 to reduce the ohmic resistance

  17. Fabrication and Testing of a Bi-Conductive Polymer Membrane Fuel Cell

    International Nuclear Information System (INIS)

    This paper reports the fabrication process and testing of a bi-conductive polymer membrane (BCPM) fuel cell that integrates lateral current collectors on both sides with an ionic conductive path through the membrane. The new membrane shows major advantages over standard Nafion® membranes used in Polymer Electrolyte Fuel Cells (PEMFCs). In addition to being mechanically stable when wet, the flexible BCPM integrates efficient thin film current collectors (ICCs) on an ionic conductive membrane with a high active area ratio. Also, ICCs leave all the surface of the electrode free to eventually integrate a more efficient water and gas management system than traditional gas diffusion layers. Moreover, the fabricated membrane has shown superior volumetric power density than standard PEMFC (0.76 vs 0.47 mW/cm2μm)

  18. 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. PMID:24600326

  19. Numerical simulation of three-dimensional gas/liquid two-phase flow in a proton exchange membrane fuel cell

    Institute of Scientific and Technical Information of China (English)

    ZHUGE Weilin; ZHANG Yangjun; MING Pingwen; LAO Xingsheng; CHEN Xiao

    2007-01-01

    Investigation into the formation and transport of liquid water in proton exchange membrane fuel cells (PEMFCs) is the key to fuel cell water management.A threedimensional gas/liquid two-phase flow and heat transfer model is developed based on the multiphase mixture theory.The reactant gas flow,diffusion,and chemical reaction as well as the liquid water transport and phase change process are modeled.Numerical simulations on liquid water distribution and its effects on the performance of a PEMFC are conducted.Results show that liquid water distributes mostly in the cathode,and predicted cell performance decreases quickly at high current density due to the obstruction of liquid water to oxygen diffusion.The simulation results agree well with experimental data.

  20. 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.

  1. Synthesis of a highly active carbon-supported Ir-V/C catalyst for the hydrogen oxidation reaction in PEMFC

    Energy Technology Data Exchange (ETDEWEB)

    Li, B.; Qiao, J.; Yang, D.; Lv, H.; Zheng, J.; Ma, J. [Tongji Univ., Shanghai (China). School of Automotive Studies, Clean Energy Automotive Engineering Center; Zhang, J.; Wang, H. [National Research Council, Vancouver, BC (Canada). Inst. for Fuel Cell Innovation

    2009-07-01

    Non-platinum catalysts are interesting candidates for use in fuel cell systems, particularly for long-term consideration. Iridium-based catalysts such as IrSn, IrOx and IrCo have very good corrosion resistance, electrical conductivity, and resistance to carbon monoxide poisoning. They also have platinum-like behaviour for the chemisorptions of hydrogen and oxygen. The Ir-based catalysts are also less expensive than platinum. In this study, carbon-supported Ir and Ir-V nanoclusters were synthesized via an ethylene glycol (EG) method using IrCl3 and NH4 VO3 as the Ir and V precursors. The nanoparticle catalysts were characterized by X-ray diffraction (XRD) and high resolution transmission electron microscope (TEM). These carbon-supported catalysts had better characteristic for hydrogen oxidation reaction. Cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) techniques were used to characterize the electrochemical properties of fuel cells by applying Ir/C and Ir-V/C as anode catalysts. According to the discharge characteristics of the fuel cell, the Ir/C and Ir-V/C catalysts affected the performance of electrocatalysts considerably. In this experiment, the catalyst Ir-V/C at 40 wt per cent exhibited the best catalytic activity to hydrogen oxidation reaction. A cell performance of 20 wt per cent higher than that for commercially available Pt/C catalysts was achieved. In addition, there was no significant deterioration in performance of the fuel cell following a 100 hour fuel cell life test at a constant current density of 1000 mA/cm{sup 2} in H{sub 2}/O{sub 2} conditions. 3 refs., 2 figs.

  2. As acessibilidades na região da Beira Interior como factor de desenvolvimento sustentável

    OpenAIRE

    Quaresma, Ana

    2010-01-01

    O desenvolvimento das acessibilidades em Portugal está a ocorrer de acordo com o previsto nas políticas europeias de transportes e em particular de acordo com o plano rodoviário nacional em vigor. Com o desenvolvimento das acessibilidades cria-se a expectativa de que as regiões por elas abrangidas registem impactos ao nível do desenvolvimento dessas mesmas regiões, principalmente nas zonas interiores, zonas que normalmente são caracterizadas por um menor desenvolvimento regional. Em ...

  3. Identificação da dislexia de desenvolvimento segundo o modelo de Dupla-Via Dis

    OpenAIRE

    Santos, Ana Rita Lourenço Martins dos

    2015-01-01

    Dissertação de Mestrado em Desenvolvimento e Perturbações da Linguagem na Criança, Área de Especialização em Terapia da Fala e Perturbações da Linguagem O presente estudo tem como objetivos identificar vários tipos de dislexia de desenvolvimento, em crianças falantes do português europeu, e verificar se a dislexia de desenvolvimento está associada a dificuldades de consciência fonológica. Foram analisados os desempenhos no Instrumento de Despiste de Dislexia de Desenvolvimento e n...

  4. A rational approach to the optimization of efficient electrocatalysts for the next generation Fuel Cells

    OpenAIRE

    Favaro, Marco

    2014-01-01

    The PhD project has been performed in the Surfaces and Catalysts group active in the Department of Chemical Sciences, within the frame of the grant “A rational approach to the optimization of efficient electrocatalysts for the next generation Fuel Cells”, funded by CARIPARO foundation. The project has been focused on the preparation and characterization of new carbon-based materials for applications in Polymer Electrolyte Membrane Fuel Cells (PEMFCs), also known as oxygen-hydrogen FCs. The pr...

  5. On the anode pressure and humidity regulation in PEM fuel cells: a nonlinear predictive control approach

    OpenAIRE

    Rosanas Boeta, Noe; Ocampo-Martínez, Carlos; Kunusch, Cristian

    2015-01-01

    In this paper, a nonlinear model predictive control (NMPC) strategy is proposed to regulate the humidity in a Proton Exchange Membrane Fuel Cell (PEMFC) anode. The proposed control strategy uses two controllers in cascade to regulate the humidity and pressure in the anode, separately. With this strategy, safety and performance constraints for pressure and humidity can be guaranteed and external disturbances, as changes in stack current demand, are rejected. Peer Reviewed

  6. Development and validation of a computational model for a proton exchange membrane fuel cell

    OpenAIRE

    Siegel, Nathan Phillip

    2003-01-01

    A steady-state computational model for a proton exchange membrane fuel cell (PEMFC) is presented. The model accounts for species transport, electrochemical kinetics, energy transport, current distribution, water uptake and release within the polymer portion of the catalyst layers, and liquid water production and transport. Both two-dimensional and three-dimensional geometries are modeled. For a given geometry, the governing differential equations are solved over a single computational domain...

  7. 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.

  8. High temperature proton exchange membranes based on polybenzimidazoles for fuel cells

    OpenAIRE

    Li, Qingfeng; Jensen, Jens Oluf; Savinell, Robert F; Bjerrum, Niels J.

    2009-01-01

    To achieve high temperature operation of proton exchange membrane fuel cells (PEMFC), preferably under ambient pressure, acid–base polymer membranes represent an effective approach. The phosphoric acid-doped polybenzimidazole membrane seems so far the most successful system in the field. It has in recent years motivated extensive research activities with great progress. This treatise is devoted to updating the development, covering polymer synthesis, membrane casting, physicochemical characte...

  9. Corrosion-resistant, electrically-conductive plate for use in a fuel cell stack

    Science.gov (United States)

    Carter, J. David; Mawdsley, Jennifer R.; Niyogi, Suhas; Wang, Xiaoping; Cruse, Terry; Santos, Lilia

    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.

  10. Fuel processors for fuel cell APU applications

    Science.gov (United States)

    Aicher, T.; Lenz, B.; Gschnell, F.; Groos, U.; Federici, F.; Caprile, L.; Parodi, L.

    The conversion of liquid hydrocarbons to a hydrogen rich product gas is a central process step in fuel processors for auxiliary power units (APUs) for vehicles of all kinds. The selection of the reforming process depends on the fuel and the type of the fuel cell. For vehicle power trains, liquid hydrocarbons like gasoline, kerosene, and diesel are utilized and, therefore, they will also be the fuel for the respective APU systems. The fuel cells commonly envisioned for mobile APU applications are molten carbonate fuel cells (MCFC), solid oxide fuel cells (SOFC), and proton exchange membrane fuel cells (PEMFC). Since high-temperature fuel cells, e.g. MCFCs or SOFCs, can be supplied with a feed gas that contains carbon monoxide (CO) their fuel processor does not require reactors for CO reduction and removal. For PEMFCs on the other hand, CO concentrations in the feed gas must not exceed 50 ppm, better 20 ppm, which requires additional reactors downstream of the reforming reactor. This paper gives an overview of the current state of the fuel processor development for APU applications and APU system developments. Furthermore, it will present the latest developments at Fraunhofer ISE regarding fuel processors for high-temperature fuel cell APU systems on board of ships and aircrafts.

  11. Structural dynamics and activity of nanocatalysts inside fuel cells by in operando atomic pair distribution studies

    Science.gov (United States)

    Petkov, Valeri; Prasai, Binay; Shan, Shiyao; Ren, Yang; Wu, Jinfang; Cronk, Hannah; Luo, Jin; Zhong, Chuan-Jian

    2016-05-01

    Here 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). In particular, using in operando high-energy X-ray diffraction (HE-XRD) 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). Experimental HE-XRD data were analysed in terms of atomic pair distribution functions (PDFs) 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. Moreover, we demonstrate how such a control can be achieved and thereby the performance of PEMFCs improved considerably. Last but not least, we argue that the unique capabilities of in operando HE-XRD coupled to atomic PDF analysis to characterize active nanocatalysts inside operating fuel cells both in a time-resolved manner and with atomic level resolution, i.e. in 4D, can serve well the ongoing search for nanocatalysts that deliver more with less platinum.Here 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). In particular, using in operando high-energy X-ray diffraction (HE

  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. O capital humano e o desenvolvimento econômico

    Directory of Open Access Journals (Sweden)

    Beatriz Maria Witkowski

    2007-07-01

    Full Text Available Um ambiente competitivo de negócios é decorrência cada vez maior de uma administração eficaz do capital humano. Estrutura, tecnologia, recursos financeiros e materiais são aspectos meramente físicos e inertes que precisam ser administrados inteligentemente por meio das pessoas que constituem a organização. A Teoria do Capital Humano é uma derivação da Teoria Econômica Neoclássica e, ao mesmo tempo, uma atualização, do axioma liberal do indivíduo livre, soberano e racional. Ressurgiu com a crise do modelo tayloris ta-fordis ta, associada à redefinição das relações de trabalho na empresa e do papel do sistema educacional. A qualidade dos funcionários de uma organização, seus conhecimentos e habilidades, entusiasmo e satisfação com seus cargos, seu senso de iniciativa para gerar riqueza, tudo isso tem forte impacto na produtividade da organização, no nível de serviço ao cliente, na reputação e na competitividade. Para qualquer que seja a área empresarial escolhida, o futuro administrador necessita ter uma visão sobre como lidar com assuntos relacionados com pessoas para alcançar o seu sucesso profissional e levar a sua organização rumo à excelência e à competitividade. Em seu conjunto, as pessoas constituem o capital humano da organização. Esse capital pode valer mais ou valer menos, na medida em que contenha talentos capazes de agregar valor à organização e torná-la mais ágil e competitiva. Portanto, esse capital vale mais na medida em que consiga influenciar as ações e os destinos da organização. A era da informação torna o trabalho menos físico e mais mental, pois as pessoas deixaram de ser fornecedoras de mão-de-obra para serem alçadas à categoria de fornecedoras de conhecimento e de competências. Do mesmo modo que o capital humano é relevante para a sociedade e para as organizações, observa-se que o desenvolvimento econômico também possui um papel de suma importância. Define

  14. An investigation into the use of additive manufacture for the production of metallic bipolar plates for polymer electrolyte fuel cell stacks

    OpenAIRE

    Dawson, Richard; Patel, Anant; Rennie, Allan; White, Simon

    2015-01-01

    The bipolar plate is of critical importance to the efficient and long lasting operation of a polymer electrolyte fuel cell (PEMFC) stack. With advances in membrane electrode assembly design, greater attention has been focused on the bipolar plate and the important role it plays. Although carbon composite plates are a likely candidate for the mass introduction of fuel cells, it is metallic plates made from thin strip materials which could deliver significant advantages in terms of part cost, e...

  15. 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

  16. 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

  17. Relatório brasileiro sobre desenvolvimento social

    Directory of Open Access Journals (Sweden)

    Luiz Felipe Lampreia

    1995-08-01

    Full Text Available O relatório nacional brasileiro, elaborado como parte do processo de preparação da participação brasileira na Cúpula Mundial para o Desenvolvimento Social, busca traçar um quadro da situação do Brasil em relação aos três temas centrais do evento: alívio e redução da pobreza, expansão do emprego produtivo e integração social. Com o objetivo de qualificar a peculiaridade dos desafios sociais com os quais o Brasil se defronta, a primeira parte consiste de um quadro abrangente, onde estão expostos os dados gerais mais relevantes. A segunda parte, de caráter conceituai, explora a relação à dicotomia desenvolvimento econômico/desenvolvimento social, políticas econômicas/políticas sociais. Passa-se, então, à parte do relatório mais diretamente ligada aos temas centrais da Cúpula. O capítulo sobre pobreza busca sistematizar algumas das principais características desse fenômeno no Brasil; em "Emprego e mercado de trabalho" examinam-se questões como a baixa taxa de desemprego aberto do mercado brasileiro e sua relação com a má qualidade dos postos de trabalho existentes; finalmente, "Integração social e políticas sociais" salienta a necessidade de novas formas de solidariedade social, o que implicaria a reformulação da lógica de financiamento das políticas sociais e sua integração num conjunto coeso, ao lado de novas parcerias do Estado com a sociedade e do setor público com o setor privado. À guisa de conclusão, alinham-se as principais diretrizes do Governo Federal para o período 1995-1999. Depois de enfatizar a necessidade de que quatro condições prévias - fortalecimento da democracia, manutenção da estabilidade econômica, recuperação do crescimento sustentado e reforma do Estado - sejam alcançadas, identificam-se cinco metas prioritárias na área social: agricultura, educação, emprego, saúde e segurança. O relatório termina com breve esboço da estrutura do Programa Comunidade Solid

  18. 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.

  19. Structural dynamics and activity of nanocatalysts inside fuel cells by in operando atomic pair distribution studies.

    Science.gov (United States)

    Petkov, Valeri; Prasai, Binay; Shan, Shiyao; Ren, Yang; Wu, Jinfang; Cronk, Hannah; Luo, Jin; Zhong, Chuan-Jian

    2016-05-19

    Here 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). In particular, using in operando high-energy X-ray diffraction (HE-XRD) 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). Experimental HE-XRD data were analysed in terms of atomic pair distribution functions (PDFs) 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. Moreover, we demonstrate how such a control can be achieved and thereby the performance of PEMFCs improved considerably. Last but not least, we argue that the unique capabilities of in operando HE-XRD coupled to atomic PDF analysis to characterize active nanocatalysts inside operating fuel cells both in a time-resolved manner and with atomic level resolution, i.e. in 4D, can serve well the ongoing search for nanocatalysts that deliver more with less platinum. PMID:27160891

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

    OpenAIRE

    Mosa Ruiz, Jadra; Durán, A; Aparicio, M.

    2007-01-01

    [ES] 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 pro...

  1. 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

    encompassing modified PFSA membranes, alternative sulfonated polymer and their composite membranes, and acidbase complex membranes. PFSA membranes have been modified by swelling with nonvolatile solvents and preparing composites with hydrophilic oxides and solid proton conductors. DMFC and H2/O2(air) cells......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...

  2. High-performance Fuel Cell with Stretched Catalyst-Coated Membrane: One-step Formation of Cracked Electrode

    Science.gov (United States)

    Kim, Sang Moon; Ahn, Chi-Yeong; Cho, Yong-Hun; Kim, Sungjun; Hwang, Wonchan; Jang, Segeun; Shin, Sungsoo; Lee, Gunhee; Sung, Yung-Eun; Choi, Mansoo

    2016-05-01

    We have achieved performance enhancement of polymer electrolyte membrane fuel cell (PEMFC) though crack generation on its electrodes. It is the first attempt to enhance the performance of PEMFC by using cracks which are generally considered as defects. The pre-defined, cracked electrode was generated by stretching a catalyst-coated Nafion membrane. With the strain-stress property of the membrane that is unique in the aspect of plastic deformation, membrane electrolyte assembly (MEA) was successfully incorporated into the fuel cell. Cracked electrodes with the variation of strain were investigated and electrochemically evaluated. Remarkably, mechanical stretching of catalyst-coated Nafion membrane led to a decrease in membrane resistance and an improvement in mass transport, which resulted in enhanced device performance.

  3. SnO2 nanocluster supported Pt catalyst with high stability for proton exchange membrane fuel cells

    International Nuclear Information System (INIS)

    Tin oxide nanocluster (SnO2) with parallel nanorods was synthesized via a hard template method and explored as the anode catalyst support for proton exchange membrane fuel cells (PEMFCs). Single cell test demonstrated that SnO2 supported Pt catalyst (Pt/SnO2) exhibited comparable anode performance with conventional Pt/C. Electrochemical measurements showed that Pt/SnO2 exhibited significantly enhanced electrochemical stability than Pt/C under high potential electro-oxidation and potential cycling. The Pt/SnO2 catalyst reserved most of its electrochemically active surface area (ECA) under 10 h potential hold at 1.6 V while its ECA degradation rate was one order of magnitude lower than Pt/C under potential cycling between 0.6 and 1.2 V. Therefore, SnO2 nanocluster can be considered as a promising alternative anode catalyst support for PEMFCs

  4. Desenvolvimento sustentável: a norma jurídica ambiental e o desenvolvimento econômico

    Directory of Open Access Journals (Sweden)

    Ana Claudia Duarte Pinheiro

    2004-12-01

    Full Text Available Since the middle of the XX century, mankind has become aware of all problems decurrent of environmental injuries caused by the excess of men themselves, who have already become conscious of their harmful acts against the environment, but actually, they haven’t changed their acts. There are many interests involved and many questions related to this subject, besides the juridical, for instance: Economy, Sociology, Philosophy, etc., yet the vital aspect concerns to the Environmental Juridical Norm, demanding Legislative ripening of each and every State of the country and their commitment with the Sustainable Development. The question implies transnationality of interests, often divergent, and culminates on the necessity of Legislative harmonization, in which the regional blocks, especially MERCOSUL, should concentrate themselves in a well-balanced way on the objectives proposed when they were created.A humanidade vem, a partir da segunda metade do século XX; tomando conhecimento de todos os problemas decorrentes dos prejuízos ambientais causados pelos desmandos do próprio homem que já se conscientizou de seus atos maléficos, mas não mudou efetivamente suas ações Há muitos interesses em jogo e são muitas as questões pertinentes à matéria, além da jurídica, como a economia, a sociologia, a filosofia etc. Aspecto, porém, de vital importância dizem respeito à norma jurídica ambiental e que exigem amadurecimento legislativo de cada um dos Estados e deles enquanto protagonistas do desenvolvimento sustentável. A questão implica em transnacionalidade de interesses muitas vezes divergentes e culmina com a necessidade de harmonização legislativa de tal forma que os blocos regionais, em especial o MERCOSUL, se concentrem de forma equilibrada nos objetivos propostos quando de sua criação.

  5. Measurement of current distribution in a proton exchange membrane fuel cell with various flow arrangements – A parametric study

    International Nuclear Information System (INIS)

    Highlights: ► Spatial local current distributions in a single PEMFC are measured. ► Effects of key operating conditions on the local current density are investigated. ► Increasing air and hydrogen stoichiometries improves local current density distributions. ► Operating pressure and temperature have negligible impact on local current distribution. - Abstract: Understanding of current distributions in proton exchange membrane fuel cells (PEMFCs) is crucial for designing cell components such as the flow field plates and the membrane electrode assembly (MEA). In this study, the spatial current density distributions in a single PEMFC with three serpentine flow channels are measured using a segmented bipolar plate and printed circuit board technique. The effects of key operating conditions such as stoichiometry ratios, inlet humidity levels, cell pressure and temperature on the local current density distributions for co-, counter-, and cross-flow arrangements are examined. It is observed that the local current density distribution over the MEA is directly affected by the cell operating conditions along with the configuration of the flow arrangement. It is also found that among the different flow configurations tested under the various operating conditions, the counter flow arrangement provides the optimum average current density and the lowest variations in the local current densities along the flow channels.

  6. Desenvolvimento do maracujá doce em Viçosa, Minas Gerais

    OpenAIRE

    Robson Ribeiro Alves; Luiz Carlos Chamhum Salomão; Dalmo Lopes de Siqueira; Paulo Roberto Cecon; Danielle Fabíola Pereira da Silva

    2013-01-01

    Foram avaliadas as mudanças físicas, químicas e fisiológicas ocorridas durante o desenvolvimento do maracujá doce, da antese até o completo amadurecimento na planta. Os frutos apresentaram formato ligeiramente oblongo, padrão de desenvolvimento sigmoidal simples e padrão climatérico para a respiração. O desenvolvimento do fruto foi dividido em três fases: divisão celular até 4,70 dias após a antese (daa), expansão celular de 4,70 daa até 28,94 daa e maturação, de 28,94 daa a 91 daa. Na primei...

  7. Development of preform moulding technique using expanded graphite for proton exchange membrane fuel cell bipolar plates

    Energy Technology Data Exchange (ETDEWEB)

    Heo, S.I.; Oh, K.S.; Yun, J.C.; Han, K.S. [Department of Mechanical Engineering, Pohang University of Science and Technology, San 31 Hyoja-dong, Nam-gu, Pohang, 790-784 (Korea); Jung, S.H.; Yang, Y.C. [Fuel Cell Vehicle Team, Advanced Technology Center, Research and Development Division for Hyundai Motor Company and Kia Motors Corporation, 104, Mabuk-dong, Giheung-Gu, Yongin, 446-912 (Korea)

    2007-09-27

    A preform moulding technique using expanded graphite is developed to manufacture composite bipolar plates for proton exchange membrane fuel cells (PEMFCs). The preform is composed of expanded graphite, graphite flake and phenol resin. Preforms utilizing the tangled structure of expanded graphite are easily fabricated at a low pressure of 0.07-0.28 MPa. A pre-curing temperature (100 C) slightly above the melting point of phenol powders (90 C) induces moderate curing, but also prevents excessive curing. After the preform is placed in a steel mould, compression moulding is carried out at high pressure (10 MPa) and temperature (150 C). The fabrication conditions are optimized by checking the electrical conductivity, flexural strength and microstructure of the composite. The optimized electrical conductivity and flexural strength, 250 S cm{sup -1} and 50 MPa, respectively, met the requirements for PEMFC bipolar plates. (author)

  8. Adaptive inverse control of air supply flow for proton exchange membrane fuel cell systems

    Institute of Scientific and Technical Information of China (English)

    LI Chun-hua; ZHU Xin-jian; SUI Sheng; HU Wan-qi; HU Ming-ruo

    2009-01-01

    To prevent the oxygen starvation and improve the system output performance, an adaptive inverse control (AIC) strategy is developed to regulate the air supply flow of a proton exchange membrane fuel cell (PEMFC) system in this paper.The PEMFC stack and the air supply system including a compressor and a supply manifold are modeled for the purpose of performance analysis and controller design. A recurrent fuzzy neural network (RFNN) is utilized to identify the inverse model of the controlled system and generates a suitable control input during the abrupt step change of external disturbances.Compared with the PI controller, numerical simulations are performed to validate the effectiveness and advantages of the proposed AIC strategy.

  9. 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)

  10. Performance and endurance of a high temperature PEM fuel cell operated on methanol reformate

    DEFF Research Database (Denmark)

    Araya, Samuel Simon; Grigoras, Ionela; Zhou, Fan;

    2014-01-01

    This paper analyzes the effects of methanol and water vapor on the performance of a high temperature proton exchange membrane fuel cell (HT-PEMFC) at varying temperatures, ranging from 140 °C to 180 °C. For the study, a H3PO4 – doped polybenzimidazole (PBI) – based membrane electrode assembly (MEA......) of 45 cm2 active surface area from BASF was employed. The study showed overall negligible effects of methanol-water vapor mixture slips on performance, even at relatively low simulated steam methanol reforming conversion of 90%, which corresponds to 3% methanol vapor by volume in the anode gas feed....... Temperature on the other hand has significant impact on the performance of an HT-PEMFC. To assess the effects of methanol-water vapor mixture alone, CO2 and CO are not considered in these tests. The analysis is based on polarization curves and impedance spectra registered for all the test points. After the...

  11. Neural network modeling and control of proton exchange membrane fuel cell

    Institute of Scientific and Technical Information of China (English)

    CHEN Yue-hua; CAO Guang-yi; ZHU Xin-jian

    2007-01-01

    A neural network model and fuzzy neural network controller was designed to control the inner impedance of a proton exchange membrane fuel cell(PEMFC)stack. A radial basis function(RBF)neural network model was trained by the input-output data of impedance. A fuzzy neural network controller Was designed to control the impedance response.The RBF neural network model was used to test the fuzzy neural network controller.The results show that the RBF model output Can imitate actual output well, themaximal errorisnotbeyond 20 mΩ, thetrainingtime is about 1 s by using 20 neurons, and the mean squared errors is 141.9 mΩ2.The impedance of the PEMFC stack is controlled within the optimum range when the load changes, and the adjustive time is ahnllt 3 rain.

  12. 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.)

  13. Biohydrogen production using green microalgae as an approach to operate a small proton exchange membrane fuel cell

    OpenAIRE

    Chader, Samira; Chetehouna, Khaled; Mahmah, Bouziane; Amrouche, Fethia; Abdeladim, Kamel

    2011-01-01

    In this paper, the wild-type of Chlorella sorokiniana a green microalga isolated from Algerian Sahara soil was tested for her ability to produce hydrogen coupled to a small Proton Exchange Membrane Fuel Cell (PEMFC). The strain was grown in heterotrophically conditions (Tris-Acetate-Phospate medium) under continuous light then it was transferred in medium without sulfur to activate the reversible hydrogenase inducing the hydrogen production process. The evolution of hydrogen and oxygen concen...

  14. New Polymer Electrolyte Membranes Based on Acid Doped PBI For Fuel Cells Operating above 100°C

    DEFF Research Database (Denmark)

    Li, Qingfeng

    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...... 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....

  15. Optimization of fuel cell membrane electrode assemblies for transition metal ion-chelating ordered mesoporous carbon cathode catalysts

    OpenAIRE

    Johanna K. Dombrovskis; Cathrin Prestel; Anders E. C. Palmqvist

    2014-01-01

    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...

  16. Desenvolvimento de um RAD para aplicações WEB (Rapid Application Development)

    OpenAIRE

    Ile, Dan Mihai

    2009-01-01

    Este documento descreve detalhadamente todo o trabalho de estágio desenvolvido durante 9 meses na empresa GEDI (Gabinete de Estudos e Divulgação Informática, SA) pelo aluno Dan Mihai Ile, no âmbito do Mestrado em Engenharia Informática da Faculdade de Ciências da Universidade de Lisboa. Consta num projecto desenvolvido com objectivo de melhorar a qualidade, metodologia de desenvolvimento e utilização da framework SIAG tanto pelos utilizadores como pela equipa de desenvolvimento...

  17. O regresso dos emigrantes portugueses e o desenvolvimento do turismo em Portugal

    OpenAIRE

    Santos, Rossana Andreia Neves dos

    2013-01-01

    Atendendo ao protagonismo que o Turismo Residencial tem vindo a assumir, no âmbito académico e político, a análise conceptual dos termos Turismo, Turismo Residencial e “Segunda Residência” revelou-se crucial nesta tese para se avaliar o seu impacte no desenvolvimento “rural”. A sua relação com as migrações (internas e internacionais) permitiu identificar o potencial que o regresso e fixação dos emigrantes portugueses apresentam para impulsionar o desenvolvimento do turismo e...

  18. Agile Data Mining: uma metodologia ágil para o desenvolvimento de projetos de data mining

    OpenAIRE

    Diogo Rafael Pinto Nogueira

    2014-01-01

    Nos últimos anos tem havido um enorme crescimento e consolidação do campo de data mining. Alguns esforço têm sido feitos para procurar estabelecer metodologias para o desenvolvimento de projetos nesta área, tal como o CRISP-DM e o SEMMA. Ainda assim o aumento do número e complexidade dos projetos, a volatilidade dos requisitos e as constantes alterações nos mercados, levam a que se encontrem problemas na metodologias atuais de desenvolvimento.O principal problema destas metodologias são os ci...

  19. Diferentes tratamentos de sementes sobre o desenvolvimento de plantas de soja

    OpenAIRE

    Ricardo Pereira da Cunha; Marciabela Fernandes Corrêa; Luis Osmar Braga Schuch; Roberto Caetano de Oliveira; José de Souza Abreu Junior; Jéssica Dias Gomes da Silva; Tainan Lopes de Almeida

    2015-01-01

    A cada ano são descobertos e utilizados novos produtos para o tratamento de sementesna cultura da soja (Glycine maxL. Merril), visando aumentos de produção. Há a necessidade de conhecer a influência desses produtos sobre o desenvolvimento das plantas, a fim de obter sucesso na atividade. O objetivo do experimento foi avaliar o efeito de principais produtos aplicados via tratamento de sementes, sobre a morfologia de plantas de soja, em diferentes fases de desenvolvimento da cultura, bem como, ...

  20. Desdobramento da qualidade no desenvolvimento de filmes flexíveis para embalagens

    OpenAIRE

    Miguel Paulo A. Cauchick; Telfser Mônica; Maruca Alexandre; Gallonetti Antônio; Saracura Aquiles; Martins Luis; Hori Mário; Ribeiro Paulo; Campos Roni de; Marconato Tanyze; Mora Valmir

    2003-01-01

    Um dos métodos atuais importantes para o desenvolvimento de produtos é o QFD (Quality Function Deployment ou Desdobramento da Função Qualidade). O QFD consiste em um processo sistemático para traduzir a opinião do cliente em requisitos técnicos e operacionais, mostrando e documentando as informações na forma de matrizes. O método objetiva enfocar os itens mais importantes, proporcionando um mecanismo para alcançar vantagens competitivas no processo de desenvolvimento. Este trabalho destaca o ...

  1. O Desenvolvimento de Cabo Verde: abordagem ao mercado de tradução

    OpenAIRE

    De Oliveira, Bruno,

    2010-01-01

    Orientador: Mestre Alberto Couto O Presente Trabalho de Projecto contextualiza o arquipélago de Cabo Verde nos aspectos histórico, geográfico, político e económico e aborda as parcerias internacionais para o seu desenvolvimento ancoradas, nomeadamente, na União Europeia, CEDEAO, Millennium Challenge Corporation e a Organização Mundial do Comércio, etc. No capítulo do desenvolvimento e internacionalização analisa-se o mercado de tradução, e de como estas novas parcerias estão...

  2. GLOBALIZAÇÃO DA P&D: IMPACTOS NOS PAÍSES EM DESENVOLVIMENTO

    OpenAIRE

    Gameiro, Mariana Bombo Perozzi; Gameiro, Augusto Hauber

    2006-01-01

    O trabalho visa analisar as conseqüências positivas e negativas advindas da globalização da pesquisa e desenvolvimento (P&D) sobre os países em desenvolvimento, especialmente os que hospedam essas operações. Para tal, empregou a revisão de literatura como metodologia. Aborda os fatores que possibilitaram a internacionalização da P&D e as vantagens buscadas pelas multinacionais que estabelecem atividades de pesquisa fora de seus países de origem. Elenca os impactos da P&D globalizada. Ressalta...

  3. Projecto de marketing digital para a APC numa perspectiva de estratégia de desenvolvimento

    OpenAIRE

    Cavez, Ana Lúcia da Silva Pereira

    2014-01-01

    Mestrado em Marketing A tese constante neste documento consiste no desenvolvimento de um plano de marketing digital para uma empresa portuguesa de fabrico de instrumentos cordofones, a APC, numa perspectiva de estratégia de desenvolvimento. Actualmente a empresa, por não possuir pessoal com formação especializada para o efeito, não gere da melhor forma a sua actuação digital, podendo até considerar-se que a sua presença nesse campo é nula ou praticamente inexistente. Apesar de estar pre...

  4. Influência dos estilos parentais no desenvolvimento do comportamento criminal dos reclusos

    OpenAIRE

    Silva, Andrea Venícia Santos Reis

    2010-01-01

    A presente investigação procura contribuir para um conhecimento mais aprofundado de uma problemática complexa – os estilos parentais e o desenvolvimento do comportamento criminal. Procura-se compreender em que medida os estilos parentais estão relacionados e influenciam o desenvolvimento do comportamento criminal de reclusos, controlando pelas características sócio-demográficas e antecedentes familiares dos sujeitos. O estudo engloba a população reclusa do Estabelecimento Prisional de C...

  5. As trilhas essenciais que fundamentam o processo e desenvolvimento da dinâmica grupal

    OpenAIRE

    Kátya Alexandrina Matos Barreto Motta; Denize Bouttelet Munari; Maria Lúcia Leal; Marcelo Medeiros; Fernanda Costa Nunes

    2007-01-01

    O grupo é um fenômeno explorado por sua importância na vida do ser humano e, assim, conhecer sua dinâmica e funcionamento é essencial aos profissionais que trabalham em qualquer área. Na saúde o desenvolvimento desse conhecimento é urgente, dado a ênfase no trabalho coletivo, inclusive no âmbito das políticas de saúde. A finalidade deste artigo de atualização é apresentar cinco trilhas essenciais para compreender o processo e desenvolvimento da dinâmica grupal, baseado no processo de formação...

  6. Agroecologia: um caminho multidimensional para o desenvolvimento agrário do Litoral Paranaense.

    OpenAIRE

    Borsatto, Ricardo Serra

    2007-01-01

    Ao se estudar o meio agrário do litoral paranaense é fácil constatar as dificuldades que este enfrenta para encontrar um caminho que permita o seu desenvolvimento sustentável. A presente dissertação visa contribuir nas discussões e consequentemente na procura de soluções para este panorama, objetivando conhecer e discutir se o conhecimento gerado pela Agroecologia pode contribuir para o desenvolvimento sustentável do litoral paranaense. Para tanto é utilizada a teoria do pensamento complexo, ...

  7. Estímulo ao desenvolvimento infantil: produção do conhecimento em enfermagem

    OpenAIRE

    Bruna Cristine Peres Falbo; Raquel Dully Andrade; Maria Cândida de Carvalho Furtado; Débora Falleiros de Mello

    2012-01-01

    Este estudo teve como objetivo identificar as ações de enfermagem para estímulo ao desenvolvimento infantil, em periódicos nacionais e internacionais, no período de 2000 a 2009. Revisão integrativa da literatura, nas bases de dados Medline e Lilacs, com análise de quinze artigos. Os resultados apontam o lúdico como essencial ao desenvolvimento infantil, devendo ser explorado pela enfermagem por meio da arte, música, brinquedos e teatro. Amenizar o estresse da hospitalização com adequação ambi...

  8. The development and treatment of impulsivity = O desenvolvimento e tratamento da impulsividade

    Directory of Open Access Journals (Sweden)

    Amorim Neto, Roque do Carmo

    2011-01-01

    Full Text Available Impulsividade é um fator presente em várias desordens psicológicas, incluindo ADHD, drogadição, comportamentos agressivos e automutiladores, e obesidade infantil. Impulsividade também é um fator de risco para o abandono de tratamento. Este artigo tem por objetivo apresentar as raízes da impulsividade do ponto de vista biológico, sociológico e do desenvolvimento humano, bem como as formas de tratamento mais comuns para pessoas com extrema impulsividade. Aqui também se inclui pesquisas das áreas de desenvolvimento neuronal e regulação emocional

  9. Aprimorando a Gerência e o Desenvolvimento de Software com Metodologias Ágeis

    OpenAIRE

    Mauricio Andreazza Sganderla; Guilherme Lacerda; Vinicius Gadis Ribeiro; Sidnei Renato Silveira

    2016-01-01

    Este artigo aborda a melhoria da gerência e construção de software utilizando as metodologias ágeis eXtreme Programming e Scrum. São aplicadas as melhores práticas de ambas as metodologias em uma equipe de desenvolvimento de software, em um ambiente em que não havia nenhum processo bem definido de desenvolvimento de software. A escolha pelo uso das metodologias ágeis foi definida, pois atende ao dinamismo do cenário atual, requisitos voláteis, ambiente mais colaborativo e menos burocrático, t...

  10. Hackers e sua relação com o surgimento e desenvolvimento da chipmusic

    Directory of Open Access Journals (Sweden)

    Camila Schäfer

    2015-07-01

    Full Text Available O presente artigo tem como objetivo relacionar as características da microcultura hacker com o surgimento e desenvolvimento da cena musical chipmusic. Para isso, utilizam-se dados divulgados amplamente sobre a cena chipmusic internacional, além de entrevistas com um grupo de músicos brasileiros. Por fim, conclui-se que, tanto a microcultura hacker, como o desenvolvimento da tecnocultura atual, têm criado nas pessoas um desejo de explorar os limites de hardwares e softwares, que, por sua vez, acaba dando origem a cenas como a chipmusic, objeto deste trabalho. 

  11. O desenvolvimento de uma comunidade de investigadores através de atividade de blogging

    OpenAIRE

    Henriques, Susana; Isolina, Oliveira

    2014-01-01

    Neste artigo, discutem-se as oportunidades educativas de um blogue no desenvolvimento de uma comunidade de investigadores, no âmbito de um programa doutoral em liderança educacional, em ambiente online,na Universidade Aberta, Portugal. O programa centra-se na investigação avançada e no desenvolvimento de processos reflexivos necessários à análise, tomada de decisão em contextos profissionais complexos, capacidade de reflexão crítica sobre as práticas e o sentido de auto-eficácia, visando cri...

  12. O modelo do processo de pré-desenvolvimento para o projeto/serviço

    OpenAIRE

    Pellegrini, Gelson Douglas

    2013-01-01

    Resumo: Essa dissertação propõe um modelo de processo de desenvolvimento de um serviço turístico (PDS) para a macrofase "Pré-Desenvolvimento", tendo como objeto a Rodoferroviária de Curitiba (PR). A requalificação da Rodoferroviária é parte integrante do plano de investimentos em obras de mobilidade para a Copa do Mundo de Futebol FIFA 2014. A gestão pública da cidade de Curitiba (PR) planejou nove obras. Este número destacou-a como a cidade-sede com a maior quantidade de obras de mobilidade ...

  13. Efeito da densidade de estocagem no desenvolvimento inicial do acará-bandeira (Pterophyllum scalare)

    OpenAIRE

    L.P. Gonçalves Júnior; S L Pereira; M.D. Matielo; P.P. Mendonça

    2013-01-01

    Avaliou-se a influência da densidade de estocagem no desenvolvimento inicial do acará-bandeira (Pterophyllum scalare). O desempenho produtivo foi avaliado pelo ganho de peso (GP), ganho de comprimento total (GCT), ganho de comprimento padrão (GCP), ganho de altura (GA), taxa de crescimento específico (TCE), taxa de desenvolvimento específico (TDE) e sobrevivência (S). Para realização do experimento, foram utilizadas 300 pós-larvas de peso médio inicial de 0,0012g, comprimento total médio de 4...

  14. Desenvolvimento do feijoeiro sob o uso de biofertilizante e adubação mineral.

    OpenAIRE

    João A. Galbiatti; Silva, Flávia G. da; Claudenir F Franco; Anaira D. Caramelo

    2011-01-01

    A produção intensiva de alimentos exige manejo adequado do solo para garantir a produtividade e a sustentabilidade ambiental. Uma das alternativas é a utilização de resíduos orgânicos no desenvolvimento das culturas, diminuindo a dependência de adubos minerais. Com o objetivo de avaliar o desenvolvimento da cultura de feijão (Phaseolus vulgaris L.), utilizando biofertilizante e adubação mineral, conduziu-se o experimento com seis tratamentos dispostos ao acaso, em esquema fatorial, em quatro ...

  15. A criança surda e o desenvolvimento da literacia

    OpenAIRE

    Almeida, Maria José Freire de

    2007-01-01

    O presente trabalho propõe-se estudar o contexto de crescimento de um grupo de jovens surdos, de modo a conhecer e compreender os factores que contribuíram, ou não, para o desenvolvimento da sua literacia. A base teórica deste estudo é constituída pela filosofia da educação bilingue e bicultural das crianças e jovens surdos e parte de dois pressupostos fundamentais: a primeira língua da criança surda é a língua gestual do seu país, essencial para o seu desenvolvimento emocio...

  16. Análise do processo de desenvolvimento de novos produtos na indústria

    OpenAIRE

    Barbeitos, José Emílio Afonso

    2015-01-01

    No âmbito da unidade curricular Dissertação/Projeto do 2º ano do Mestrado em Engenharia mecânica – Ramo Gestão Industrial do Instituto Superior de Engenharia do Porto, o presente trabalho enquadra-se na análise do processo de desenvolvimento de novos produtos na indústria, como suporte à gestão de projetos. No seguimento da necessidade que as empresas têm cada vez mais presente em investirem na melhoria do processo de desenvolvimento de novos produtos, isso conduz a uma gara...

  17. DESENVOLVIMENTO DE BALAS MASTIGÁVEIS ADICIONADAS DE INULINA

    Directory of Open Access Journals (Sweden)

    ALEX AUGUSTO GONÇALVES

    2010-03-01

    Full Text Available

    O segmento de confeitos em geral, onde se destacam as balas, está muito presente no cenário brasileiro e mundial. As indústrias vêm constantemente aprimorando seus produtos com a incorporação de novos ingredientes e tecnologias, para atender principalmente as necessidades exigidas pelos consumidores, que estão cada vez mais exigentes em relação à qualidade do produto a ser consumido. Com base nesta premissa e vislumbrando atender esta nova tendência de mercado a proposta deste trabalho foi o desenvolvimento de uma bala mastigável adicionada de inulina. A inulina é um carboidrato (frutano que não é digerido no trato gastro-intestinal superior do ser humano, e exerce efeito bifidogênico, estimulando o crescimento e/ou a atividade das bactérias benéficas do cólon, ajudando na manutenção da fl ora intestinal e prevenção do câncer (prebiótico. Foram desenvolvidas duas formulações de balas mastigáveis, com e sem inulina na composição. Realizaram- se análises microbiológicas, físico-químicas e análise sensorial. As amostras analisadas adequaram-se à legislação brasileira nos parâmetros físico-químicos e microbiológicos avaliados e, quanto à análise sensorial, observou-se boa aceitação do produto. A adição de inulina à formulação trouxe uma variação significativa no atributo textura, tendo um aumento na maciez do produto final.

  18. Promessa e desafios do desenvolvimento Promises and challenges of development

    Directory of Open Access Journals (Sweden)

    Gary Gereffi

    2007-06-01

    Full Text Available 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 regulação internacional com a gradual retração, a partir de 2005, do sistema de quotas estabelecido pelo Acordo Multifibras. As trajetórias de aprimoramento industrial manifestadas pela China e México são comparadas neste texto; com base em dados do comércio internacional, faz-se uma análise mais detida da composição das suas exportações destinadas ao mercado norte-americano no que respeita a ramos e produtos-chave. A experiência chinesa das chamadas "cidades-cadeias-de-suprimento" é também analisada; trata-se de uma nova forma de organização econômica, voltada a integrar geograficamente a produção para exportação e outros segmentos de alto valor agregado das cadeias globais de valor.The global economy is changing rapidly, and China, India, and Mexico represent particularly interesting cases because of their divergent development models. Global consolidation is increasing in the past decade because of the rapid growth of China in manufacturing export industries, and India's surge in the offshoring of information technology services. The apparel industry also illustrates the consolidation trend because of a shift in international regulation with the phase out in 2005 of the quotas associated with the Multi-Fiber Arrangement. Industrial upgrading trajectories in China and Mexico are compared, using international trade data to look closely at export profiles in key industries and products destined for the U.S. market. China

  19. 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

    2016-05-01

    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.

  20. A transient PEMFC model with CO poisoning and mitigation by O{sub 2} bleeding and Ru-containing catalyst

    Energy Technology Data Exchange (ETDEWEB)

    Shah, A.A. [Queen' s, RMC Fuel Cell Research Centre, 945 Princess Street, Kingston, Ont. K7L 5L9 (Canada); Sui, P.C. [Institute for Integrated Energy Systems, University of Victoria, Victoria, BC V8W 3P6 (Canada); Kim, G.-S.; Ye, S. [Ballard Power Systems, 4343 North Fraser Way, Burnaby, BC V5J 5J9 (Canada)

    2007-03-30

    In this paper we present a transient, fully two-phase, non-isothermal model of carbon monoxide poisoning and oxygen bleeding in the membrane electrode assembly of a polymer electrolyte fuel cell. The model includes a detailed description of mass, heat and charge transport, chemisorption, electrochemical oxidation and heterogeneous catalysis (when oxygen is introduced). Example simulation results demonstrate the ability of the model to qualitatively capture the fundamental features of the poisoning process and the extent of poisoning with respect to channel temperature and concentration. Further examples show how the multi-step kinetics can interact with other physical phenomena such as liquid-water flooding, particularly in the anode. Carbon monoxide pulsing is simulated to demonstrate that the complicated reaction kinetics of oxygen bleeding can be captured and even predicted. It is shown that variations in the channel temperature have a convoluted effect on bleeding, and that trends in performance on relatively short time scales can be the precise opposite of the trends observed at steady state. We incorporate a bi-functional mechanism for carbon monoxide oxidation on platinum-ruthenium catalysts, demonstrating the marked reduction in the extent of poisoning, the effect of variations in the platinum-ruthenium ratio and the influence of temperature. Finally, we discuss the implications of the results, extensions to the model and possible avenues for experimental work. (author)

  1. 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.

  2. Addition of sulfonated silicon dioxide on an anode catalyst layer to improve the performance of a self-humidifying proton exchange membrane fuel cell

    Science.gov (United States)

    Lin, Chien-Liang; Hsu, Shih-Chieh; Ho, Wei-Yu

    2016-03-01

    Sulfonated SiO2 was added on an anode catalyst layer to manufacture a hygroscopic electrode for self-humidifying proton exchange membrane fuel cells (PEMFCs). The inherent humidity of a proton exchange membrane (PEM) determines the electrical performance of PEMFCs. To maintain the high moisture content of the PEM, self-humidifying PEMFCs can use the water produced by the fuel cell reaction and, thus, do not require external humidification. Scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy, and water contact angle measurement tests were performed to characterize the structures and properties of sulfonated SiO2 and the related electrodes, and the electric current and voltage (I-V) performance curve tests for the fuel cells were conducted under differing gas humidification conditions. When 0.01mg/cm2 of sulfonated SiO2 was added, the electrical performance of the fuel cells (50∘C) increased 29% and 59% when the fuel cell reaction gases were humidified at 70∘C and 50∘C, respectively.

  3. Mechanical Stability of H3PO4-Doped PBI/Hydrophilic-Pretreated PTFE Membranes for High Temperature PEMFCs

    International Nuclear Information System (INIS)

    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

  4. 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.

  5. Proton exchange membrane fuel cells for space and electric vehicle applications: From basic research to technology development

    Science.gov (United States)

    Srinivasan, Supramaniam; Mukerjee, Sanjeev; Parthasarathy, A.; CesarFerreira, A.; Wakizoe, Masanobu; Rho, Yong Woo; Kim, Junbom; Mosdale, Renaut A.; Paetzold, Ronald F.; Lee, James

    1994-01-01

    The proton exchange membrane fuel cell (PEMFC) is one of the most promising electrochemical power sources for space and electric vehicle applications. The wide spectrum of R&D activities on PEMFC's, carried out in our Center from 1988 to date, is as follows (1) Electrode Kinetic and Electrocatalysis of Oxygen Reduction; (2) Optimization of Structures of Electrodes and of Membrane and Electrode Assemblies; (3) Selection and Evaluation of Advanced Proton Conducting Membranes and of Operating Conditions to Attain High Energy Efficiency; (4) Modeling Analysis of Fuel Cell Performance and of Thermal and Water Management; and (5) Engineering Design and Development of Multicell Stacks. The accomplishments on these tasks may be summarized as follows: (1) A microelectrode technique was developed to determine the electrode kinetic parameters for the fuel cell reactions and mass transport parameters for the H2 and O2 reactants in the proton conducting membrane. (2) High energy efficiencies and high power densities were demonstrated in PEMFCs with low platinum loading electrodes (0.4 mg/cm(exp 2) or less), advanced membranes and optimized structures of membrane and electrode assemblies, as well as operating conditions. (3) The modeling analyses revealed methods to minimize mass transport limitations, particularly with air as the cathodic reactant; and for efficient thermal and water management. (4) Work is in progress to develop multi-kilowatt stacks with the electrodes containing low platinum loadings.

  6. Cost Analysis of Fuel Cell Systems for Transportation Compressed Hydrogen and PEM Fuel Cell System

    Energy Technology Data Exchange (ETDEWEB)

    Eric J. Carlson

    2004-10-20

    PEMFC technology for transportation must be competitive with internal combustion engine powertrains in a number of key metrics, including performance, life, reliability, and cost. Demonstration of PEMFC cost competitiveness has its own challenges because the technology has not been applied to high volume automotive markets. The key stack materials including membranes, electrodes, bipolar plates, and gas diffusion layers have not been produced in automotive volumes to the exacting quality requirements that will be needed for high stack yields and to the evolving property specifications of high performance automotive stacks. Additionally, balance-of-plant components for air, water, and thermal management are being developed to meet the unique requirements of fuel cell systems. To address the question of whether fuel cells will be cost competitive in automotive markets, the DOE has funded this project to assess the high volume production cost of PEM fuel cell systems. In this report a historical perspective of our efforts in assessment of PEMFC cost for DOE is provided along with a more in-depth assessment of the cost of compressed hydrogen storage is provided. Additionally, the hydrogen storage costs were incorporated into a system cost update for 2004. Assessment of cost involves understanding not only material and production costs, but also critical performance metrics, i.e., stack power density and associated catalyst loadings that scale the system components. We will discuss the factors influencing the selection of the system specification (i.e., efficiency, reformate versus direct hydrogen, and power output) and how these have evolved over time. The reported costs reflect internal estimates and feedback from component developers and the car companies. Uncertainty in the cost projection was addressed through sensitivity analyses.

  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

    OpenAIRE

    Fernanda Mafra Cajú; Gian Carlo D'Angelo Queiroz; Sandra Maria Torres; Bruno Mendes Tenório; Valdemiro Amaro Silva Júnior

    2011-01-01

    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 ...

  8. 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

  9. 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)

  10. Modeling and control of a small solar fuel cell hybrid energy system

    Institute of Scientific and Technical Information of China (English)

    LI Wei; ZHU Xin-jian; CAO Guang-yi

    2007-01-01

    This paper describes a solar photovoltaic fuel cell (PVEC) hybrid generation system consisting of a photovoltaic (PV) generator, a proton exchange membrane fuel cell (PEMFC), an electrolyser, a supercapacitor, a storage gas tank and power conditioning unit (PCU). The load is supplied from the PV generator with a fuel cell working in parallel. Excess PV energy when available is converted to hydrogen using an electrolyser for later use in the fuel cell. The individual mathematical model for each component is presented. Control strategy for the system is described. MATLAB/Simulink is used for the simulation of this highly nonlinear hybrid energy system. The simulation results are shown in the paper.

  11. Estímulo ao desenvolvimento infantil: produção do conhecimento em enfermagem

    Directory of Open Access Journals (Sweden)

    Bruna Cristine Peres Falbo

    2012-02-01

    Full Text Available Este estudo teve como objetivo identificar as ações de enfermagem para estímulo ao desenvolvimento infantil, em periódicos nacionais e internacionais, no período de 2000 a 2009. Revisão integrativa da literatura, nas bases de dados Medline e Lilacs, com análise de quinze artigos. Os resultados apontam o lúdico como essencial ao desenvolvimento infantil, devendo ser explorado pela enfermagem por meio da arte, música, brinquedos e teatro. Amenizar o estresse da hospitalização com adequação ambiental reduz o seu impacto sobre o desenvolvimento infantil. Orientar e intervir nos inter-relacionamentos são ações de enfermagem para o desenvolvimento social e comportamental infantil. Os temas abordados na literatura são fundamentais para uma prática de enfermagem no cuidado integral à saúde da criança.

  12. Planos diretores: o caminho para o desenvolvimento sustentável das cidades

    Directory of Open Access Journals (Sweden)

    Alexsandro da Miranda

    2013-11-01

    Full Text Available Os Planos Diretores efetivam a existência de uma legislação geral estabelecendo as normas necessárias à implementação de políticas urbanas, previstas na Constituição Federal e no Estatuto da Cidade (Lei Federal 10.257/2001 e que em seu foco principal está o desenvolvimento e a expansão urbana.  Assim, o presente artigo aborda uma breve discussão teórica do tema, suas problemáticas e contextualizações na perspectiva de fundamentá-las à luz das teorias existentes. Três principais diretrizes devem ser destacadas: o desenvolvimento sustentável, a gestão democrática da cidade e o planejamento do desenvolvimento das cidades, onde os municípios, devem, portanto, utilizar as diretrizes e instrumentos do Estatuto da Cidade com o objetivo de estabelecer as regras que propiciem o pleno desenvolvimento econômico, social, ambiental e sustentável, com vistas a garantir o direito à cidade para todos os que nela vivem.

  13. Riscos biopsicossociais para o desenvolvimento de crianças prematuras e com baixo peso

    Directory of Open Access Journals (Sweden)

    Kelly Ambrósio Silveira

    2012-12-01

    Full Text Available A prematuridade (PT e o baixo peso ao nascimento (BP são fatores de risco para o desenvolvimento, assim como as variáveis psicossociais. Este estudo teve por objetivo descrever e analisar as relações entre variáveis psicossociais e de nascimento e o desempenho cognitivo, linguístico, motor e comportamental em crianças nascidas PTBP, com idade de 12 a 36 meses. Essas relações foram estudadas em 40 crianças PTBP, com 12-36 meses de idade, avaliadas pela Bayley-III Screening Test (BSID-III, e também em seus pais, que responderam ao Child Behavior Checklist (CBCL 1½-5 anos e à entrevista para identificação de riscos biopsicossociais. Prontuários médicos também foram consultados. Identificou-se maior frequência de risco para problemas de desenvolvimento na área cognitiva e de linguagem expressiva. Destacam-se as correlações entre condições de nascimento e problemas de desenvolvimento, risco psicossocial severo e riscos à linguagem receptiva e a problemas comportamentais, bem como entre os últimos e riscos à linguagem expressiva e à cognição. Aponta-se a necessidade de monitoramento do desenvolvimento dessas crianças, com atividades de avaliação, estimulação precoce e atendimento familiar.

  14. Meio ambiente, Celso Furtado e o desenvolvimento como falácia

    Directory of Open Access Journals (Sweden)

    Cavalcanti Clóvis

    2003-01-01

    Full Text Available O trabalho de Celso Furtado como pensador social é conhecido por suas enormes contribuições ao entendimento dos problemas do desenvolvimento no contexto dos países subdesenvolvidos. Sua teoria do subdesenvolvimentom, elaborada há quatro décadas, persiste como uma visão atual da realidade. Furtado repassa constantemente conceitos como o de dependência, concentração de renda, mimetismo cultural, relações assimétrias centro-periferia, mercado interno e muitos outros, além de trabalhar uma visão estruturalista do subdesenvolvimento, do desenvolvimento e de fenômenos correlatos. No livro O Mito do Desenvolvimento ele levanta duas questões não comuns ao restante da sua obra. A primeira delas diz respeito aos impactos do processo econômico no meio físico, na natureza _ um tema completamente alheio ao núcleo do pensamento tradicional da ciência da economia . A segunda se refere à constatação do caráter de mito moderno do desenvolvimento econômico. Que Furtado tenha feito isso em 1974, época do Milagre, demonstra o vigor de seu pensamento visionário. Vale a pena voltar ao assunto. É o que se faz no artigo.

  15. As NICSPs e a Contabilidade Governamental de Países em Desenvolvimento

    Directory of Open Access Journals (Sweden)

    James L. Chan

    2010-04-01

    Full Text Available Com o objetivo de alcançarem metas socioeconômicas ambiciosas, países em desenvolvimento precisam desenvolver capacidade institucional no setor público para estabelecer e implementar políticas públicas, as quais, por sua vez, prescindem de uma reforma na sua contabilidade governamental. O valor social da reforma na contabilidade governamental repousa, portanto, na sua contribuição para as metas de desenvolvimento, inclusive de redução da pobreza. Essa fundamentação tem conduzido os doadores e os financiadores internacionais e multilaterais a endossar as Normas Internacionais de Contabilidade para o Setor Público (NICSPs e a sua adoção em países em desenvolvimento. A ênfase em assegurar a integridade financeira e a mudança para o regime de competência pode tornar as NICSPs mais úteis na reforma da contabilidade pública em países em desenvolvimento.

  16. Avaliação do crescimento e desenvolvimento de crianças institucionalizadas

    Directory of Open Access Journals (Sweden)

    Caroline Magna Pessoa Chaves

    2013-10-01

    Full Text Available O estudo objetivou avaliar o crescimento e desenvolvimento de crianças de 0 a 6 anos institucionalizadas. Abordagem descritiva, transversal e de natureza quantitativa. Foi realizado em um abrigo da Secretaria do Trabalho e Desenvolvimento Social do Governo do Estado do Ceará, nos meses de março e abril de 2011. A amostra foi composta por 44 crianças. Prevaleceram crianças de sexo masculino (59,1%; faixa etária entre 24 a 72 meses (56,8%, e tempo de abrigamento superior a um ano (72,7%. Verificou-se que as crianças estavam na faixa de normalidade nutricional. Porém, 65,9% das crianças não alcançaram pelo menos um dos marcos do desenvolvimento propostos pelo Ministério da Saúde. O estudo possibilitou uma reflexão sobre como as crianças residentes em abrigos estão sendo assistidas pela equipe de saúde, tornando-se necessário realizar o acompanhamento de seu crescimento e desenvolvimento, a fim de intervir sobre as alterações encontradas.

  17. Oportunidades do ambiente domiciliar para o desenvolvimento motor

    Directory of Open Access Journals (Sweden)

    Érica Cesário Defilipo

    2012-08-01

    Full Text Available OBJETIVO: Avaliar as oportunidades presentes no ambiente domiciliar para o desenvolvimento motor de lactentes. MÉTODOS: Estudo epidemiológico de base populacional, transversal, realizado com 239 lactentes com idade entre três e 18 meses, residentes no município de Juiz de Fora, MG, em 2010. Os participantes foram selecionados por amostragem aleatória estratificada, conglomerada, em múltiplos estágios. Para avaliar a qualidade e quantidade de estímulo motor no ambiente domiciliar foi utilizado o instrumento Affordance in the Home Environment for Motor Development - Infant Scale. Procedeu-se a análise bivariada com aplicação do teste qui-quadrado, seguida de regressão logística multinomial para verificar a associação entre as oportunidades presentes no domicílio e fatores biológicos, comportamentais, demográficos e socioeconômicos. RESULTADOS: As oportunidades de estimulação ambiental foram relativamente baixas. Na análise bivariada, para a faixa etária de três a nove meses, foi encontrada associação com os fatores: ordem de nascimento (p = 0,06, classificação socioeconômica (p = 0,08, renda mensal (p = 0,06 e renda per capita (p = 0,03. No modelo de regressão, prevaleceu a classificação socioeconômica (RC = 7,46; p = 0,03. Para a faixa etária de dez a 18 meses, os fatores associados, na análise bivariada, foram: estado civil materno (p < 0,01, convívio da criança com o pai (p = 0,08, chefe da família (p = 0,04, número de pessoas no domicílio (p = 0,05, escolaridade materna (p < 0,01 e paterna (p < 0,01, classificação socioeconômica (p < 0,01 e renda per capita (p = 0,03. No modelo de regressão, o estado civil materno (RC = 4,83; p = 0,02, escolaridade materna (RC = 0,29; p = 0,03 e paterna (RC = 0,33; p = 0,04 permaneceram associados às oportunidades de estimulação ambiental. CONCLUSÕES: A união estável dos pais, maior escolaridade materna e paterna e maior nível econômico foram os fatores

  18. Fabrication of polymer electrolyte membranes fuel cell as reduction of ETFE film polymer structure using electron beam

    International Nuclear Information System (INIS)

    Crosslinking of ETFE polymer electrolyte membranes (PEMs) by combining several sources such as, -Electron beam (EB) -Thermal energy Characteristics of ETFE membrane: Ion exchange capacity (IEC), Water-uptake(WU) Size increment(SI), Tensile test, Chemical resistance Ionic conductivity (IC) Electric characteristics in PEMFC. Grafting monomer: Styrene (S), Methylstyrene (MS), Ion exchange capacity: Titration method with 0.1N NaOH Water-uptake : 24hr in DI water, room temp. = 26 .deg. C Tensile test: In stron analyzer Chemical resistance: 28% H2O2, 50 .deg. C Size increment: % wt-change after Di water-swelled at 26 .deg. C and for 24hr Ionic conductivity: 4 probe, measured in DI water at 26 .deg. C Electric characteristics: PEMFC (H2/O2), Cell size : 1 Χ 1 cm2 Temp. range: 50∼70 .deg. C, Pt loading : 0.4mg/cm2

  19. 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

    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...... 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...... corrosion triggered platinum detachment; and (4) influencing transport property of the soluble platinum species (SPS) which may redeposit. Strict control of the lamination conditions is needed in order to avoid damage of the polymer and degradation of the catalyst....

  20. 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.