WorldWideScience

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. 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.

  6. 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

  7. 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...

  8. 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.

  9. 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...

  10. 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

  11. 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)

  12. 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.

  13. 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

  14. 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)

  15. 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.

  16. 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)

  17. 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

  18. 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)

  19. Current status and challenges in PEMFC stacks, systems and commercialization

    Institute of Scientific and Technical Information of China (English)

    任远; 曹广益; 朱新坚

    2006-01-01

    The current status of worldwide developments of polymer electrolyte membrane fuel cell (PEMFC) stacks and system,research activities in resent years to analyze the cost of PEMFC stacks and systems, the remaining research and development issues that should be resolved before the PEMFC available for commercial application were discussed. The two main problems that challenge the PEMFC commercialization were cost and fuel supply infrastructure. The ways to lower the cost, to choose the fuel and improve the efficiency and reliability were described. To research the cost target of 125 kW and stack lifetime of 40 000 ~ 100 000h, basic research in PEMFC was indispensable.

  20. 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.

  1. 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)

  2. 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

  3. 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.)

  4. 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)

  5. 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)

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2006-07-01

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

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

    Directory of Open Access Journals (Sweden)

    Zulkepli Afzam

    2016-01-01

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

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

    DEFF Research Database (Denmark)

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

    2010-01-01

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

  9. 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

  10. Investigation on the origin of diffusion impedance in the porous cathode of a proton exchange membrane fuel cell (PEMFC) via electrochemical impedance spectroscopy (EIS)

    Energy Technology Data Exchange (ETDEWEB)

    Mainka, J.; Maranzana, G.; Dillet, J.; Didierjean, S.; Lottin, O. [Nancy Univ., Centre national de la recherche scientifique, Vandoeuvre les Nancy (France). Laboratoire d' Energetique et de Mecanique Theorique et Appliquee

    2009-07-01

    This study provided a preliminary examination of the impact of gas flow rate on the impedance characteristics of a proton exchange membrane fuel cell (PEMFC). The mass transport phenomena within the porous cathode of PEMFCs can be analyzed through electrochemical impedance spectroscopy (EIS). The geometrical description of the electrodes chosen to complete the EIS interpretations is a form of the agglomerate model, where the agglomerates are a mixture of carbon powder and catalyst particles, whereas the electrolyte is assumed to cover only the pore surfaces. Therefore, the reactants access the active catalyst sites by passing successively through the gas diffusion layer (GDL), the pores of the electrode, and finally through a thin electrolyte layer. The fuel cell equivalent electrical circuit is based on a Butler-Volmer formalism that takes into consideration oxygen diffusion in the pores of the GDL and/or the active layer through a Warburg element. The results reveal that in the cathode, the mass transfer limiting layer is most likely the active layer, provided liquid water is present within the pores. Under normal operating conditions, the mass transport resistance of the gas diffusion layer is negligible, as is the fine electrolyte layer coating the agglomerate.

  11. 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...

  12. 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.

  13. 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

  14. 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.

  15. 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)

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2000-07-01

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

  17. 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)

  18. 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.

  19. 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.

  20. 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.

  1. 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.

  2. 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)

  3. 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...

  4. 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...

  5. 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.

  6. 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)

  7. Review on management, mechanisms and modelling of thermal processes in PEMFC

    Science.gov (United States)

    Bvumbe, Tatenda J.; Bujlo, Piotr; Tolj, Ivan; Mouton, Kobus; Swart, Gerhard; Pasupathi, Sivakumar; Pollet, Bruno G.

    2016-06-01

    In an effort to reduce the environmental impact of the energy sector that is mostly based on fossil fuels, researchers are looking for a clean alternative of our existing energy sources. Hydrogen Energy and Fuel Cells, and in particular Polymer ElectrolyteMembrane Fuel Cells (PEMFCs) have emerged as a leading candidate for transportation as well as stationary and portable applications. Due to the irreversibility of the electrochemical reactions and ohmic heating in the fuel cell components, the PEMFC produces a significant amount of heat and this heat has to be removed in order to avoid cell or stack overheating. In this paper, a review of the key heat transfer mechanisms and the various cooling strategies that are available for heat removal from PEMFCs are presented. Due to the interrelated nature and difficulty of conducting in-situ thermal measurements on the operating PEMFCs, computational modelling provides a fast and efficient way of designing PEMFC cooling systems and understanding the heat transfer mechanisms. Therefore PEMFC thermal modelling is also highlighted together with present challenges and potential areas for further research and development works.

  8. Oxygen starvation analysis during air feeding faults in PEMFC

    Energy Technology Data Exchange (ETDEWEB)

    Gerard, Mathias [Commissariat a l' Energie Atomique (CEA), DRT/LITEN, 17, rue des Martyrs -38000 Grenoble (France); University of Franche-Comte, FEMTO-ST ENISYS/FCLAB Laboratory, rue Thierry Mieg, bat. F -90010 Belfort (France); Poirot-Crouvezier, Jean-Philippe [Commissariat a l' Energie Atomique (CEA), DRT/LITEN, 17, rue des Martyrs -38000 Grenoble (France); Hissel, Daniel; Pera, Marie-Cecile [University of Franche-Comte, FEMTO-ST ENISYS/FCLAB Laboratory, rue Thierry Mieg, bat. F -90010 Belfort (France)

    2010-11-15

    A new analysis of performance degradation during oxygen starvation of PEMFC (Proton Exchange Membrane Fuel Cell) is proposed in this paper. Oxygen starvation happens for several reasons like compressor delay, fault during peak power demand or water management issues. The consequences on fuel cell performance degradation are not still well understood. This paper proposes a complete study with experimental tests and modeling. Impacts on performance were investigated under oxygen starvation and effects on the local conditions in the MEA (Membrane Electrode Assembly) were measured and modeled. In particular, current density measurements during oxygen starvation have been made with a specific bi-cell stack. Voltage oscillations were also found. Durability test have been realized on a PEMFC stack. Samples from the degraded MEA were analyzed by TEM (Transmission Electron Microscopy). Degradation mechanisms are proposed and the local conditions during oxygen starvation are identified. (author)

  9. 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.

  10. Monte Carlo simulation of the PEMFC catalyst layer

    Institute of Scientific and Technical Information of China (English)

    WANG Hongxing; CAO Pengzhen; WANG Yuxin

    2007-01-01

    The performance of the polymer electrolyte membrane fuel cell (PEMFC) is greatly controlled by the structure of the catalyst layer.Low catalyst utilization is still a significant obstacle to the commercialization of the PEMFC.In order to get a fundamental understanding of the electrode structure and to find the limiting factor in the low catalyst utilization,it is necessary to develop the mechanical model on the effect of catalyst layer structure on the catalyst utilization and the performance of the PEMFC.In this work,the structure of the catalyst layer is studied based on the lattice model with the Monte Carlo simulation.The model can predict the effects of some catalyst layer components,such as Pt/C catalyst,electrolyte and gas pores,on the utilization of the catalyst and the cell performance.The simulation result shows that the aggregation of conduction grains can greatly affect the degree of catalyst utilization.The better the dispersion of the conduction grains,the larger the total effective area of the catalyst is.To achieve higher utilization,catalyst layer components must be distributed by means of engineered design,which can prevent aggregation.

  11. 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

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

    DEFF Research Database (Denmark)

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

    2011-01-01

    A detailed thermodynamic, kinetic and geometric model of a micro-CHP (Combined-Heatand-Power) residential system based on High Temperature-Proton Exchange Membrane Fuel Cell (HT-PEMFC) technology is developed, implemented and validated. HT-PEMFC technology is investigated as a possible candidate ...

  13. 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.

  14. 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.

  15. 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)

  16. 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.

  17. 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...

  18. 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.

  19. Dynamic modeling and simulation test of a 60 kW PEMFC generation system

    Institute of Scientific and Technical Information of China (English)

    Ying-ying ZHANG; Ji-chang SUN; Ying ZHANG; Xi LI; Guang-yi CAO

    2011-01-01

    In this paper, a 60 kW proton exchange membrane fuel cell (PEMFC) generation system is modeled in order to design the system parameters and investigate the static and dynamic characteristics for control purposes. To achieve an overall system model, the system is divided into five modules: the PEMFC stack (anode and cathode flows, membrane hydration, and stack voltage and power), cathode air supply (air compressor, supply manifold, cooler, and humidifier), anode fuel supply (hydrogen valve and humidifier), cathode exhaust exit (exit manifold and water return), and power conditioning (DC/DC and DC/AC) modules. Using a combination of empirical and physical modeling techniques, the model is developed to set the operation conditions of current, temperature, and cathode and anode gas flows and pressures, which have major impacts on system performance.The current model is based on a 60 kW PEMFC power plant designed for residential applications and takes account of the electrochemical and thermal aspects of chemical reactions within the stack as well as flows of reactants across the system. The simulation tests show that the system model can represent the static and dynamic characteristics of a 60 kW PEMFC generation system, which is mathematically simple for system parameters and control designs.

  20. Identification of the Hammerstein model of a PEMFC stack based on least squares support vector machines

    Energy Technology Data Exchange (ETDEWEB)

    Li, Chun-Hua; Zhu, Xin-Jian; Cao, Guang-Yi; Sui, Sheng; Hu, Ming-Ruo [Fuel Cell Research Institute, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai 200240 (China)

    2008-01-03

    This paper reports a Hammerstein modeling study of a proton exchange membrane fuel cell (PEMFC) stack using least squares support vector machines (LS-SVM). PEMFC is a complex nonlinear, multi-input and multi-output (MIMO) system that is hard to model by traditional methodologies. Due to the generalization performance of LS-SVM being independent of the dimensionality of the input data and the particularly simple structure of the Hammerstein model, a MIMO SVM-ARX (linear autoregression model with exogenous input) Hammerstein model is used to represent the PEMFC stack in this paper. The linear model parameters and the static nonlinearity can be obtained simultaneously by solving a set of linear equations followed by the singular value decomposition (SVD). The simulation tests demonstrate the obtained SVM-ARX Hammerstein model can efficiently approximate the dynamic behavior of a PEMFC stack. Furthermore, based on the proposed SVM-ARX Hammerstein model, valid control strategy studies such as predictive control, robust control can be developed. (author)

  1. 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.

  2. Development of a novel portable-size PEMFC short stack with electrodeposited Pt hydrogen diffusion anodes

    Energy Technology Data Exchange (ETDEWEB)

    Alcaide, Francisco; Alvarez, Garbine; Blazquez, Jose Alberto; Miguel, Oscar [Dpto. de Energia, CIDETEC-IK4, P Miramon, 196, 20009 San Sebastian (Spain); Cabot, Pere L. [Laboratori d' Electroquimica de Materials i del Medi Ambient, Dept. Quimica Fisica, Universitat de Barcelona, Marti i Franques, 1-11, 08028 Barcelona (Spain)

    2010-06-15

    This paper presents, for the first time, a five-cell polymer electrolyte membrane fuel cell (PEMFC) short stack with electrodeposited hydrogen diffusion anodes. The anodes were manufactured by means of galvanostatic pulse electrodeposition and the cathodes by air-brushing. Nafion {sup registered} 212 was employed as a solid polymer electrolyte membrane in all cases. The short stack, whose cells had an active geometric area of 14 cm{sup 2}, was assembled and tested under different operating conditions. A peak power of about 11 W was obtained at 50 C and atmospheric pressure using hydrogen and air feed, whereas a smaller value of 8.6 W was obtained from a five-cell short PEMFC stack with conventional hydrogen diffusion anodes under the same operating conditions. The better performance of the cells described in this paper has been assigned to the higher utilization of the platinum in the electrodeposited anodes compared to the conventional ones. (author)

  3. 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

    overpotentials in the cells. Moreover, it is zero-dimensional and is assumed to be steady state. The system includes a compressor, an air humidifier, a set of heat exchangers, and a stack that together build up the anode circuit, the cathode circuit, and the cooling loop. Several issues are discussed: water...... for the auxilary components depending on the stack power or current. Further, at the higher current densities, heat losses and net power of the system increase, while system efficiency decreases. Furthermore, the system performance was not sensitive to the coolant temperature when water is used as the coolant....

  4. Experimental investigation on a polymer electrolyte membrane fuel cell (PEMFC) parallel flow field design with external two-valve regulation on cathode channels

    Science.gov (United States)

    Tong, Shijie; Bachman, John C.; Santamaria, Anthony; Park, Jae Wan

    2013-11-01

    Parallel/interdigitated/serpentine flow field PEM fuel cells have similar performance under low overvoltage operation. At higher overvoltage, interdigitated/serpentine flow field performance may exceed parallel flow field designs due to better water removal and more uniform reactant distribution by convective reactant flow in the GDL under land area, i.e. cross flow. However, serpentine flow field design suffers from high pumping losses and the risk of local flooding at channel U-bends. Additionally, interdigitated flow field designs may have higher local flooding risk in the inlet channels and relatively large pumping requirement at low current densities. In this study, a novel parallel flow field design with external two-valve regulation on the cathode was presented. Two valves introduced continuous pressure differences to two separate manifolds in the cathode that induce cross flow across the land areas. Moreover, both valves remained partially open to maintain a good water removal from flow channels. Comparative test results showed the proposed design surpasses performance of both parallel and interdigitated flow field design at operation current density of 0.7 A cm-2 or higher. The performance enhancement is 10.9% at peak power density point (0.387 W cm-2 @ 0.99 A cm-2) compared to parallel flow field taking into account pumping losses.

  5. 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)

  6. Online humidification diagnosis of a PEMFC using a static DC-DC converter

    Energy Technology Data Exchange (ETDEWEB)

    Hinaje, M.; Sadli, I.; Martin, J.-P.; Thounthong, P.; Rael, S.; Davat, B. [GREEN - Institut National Polytechnique de Lorraine 2, Avenue de la Foret de Haye, 54516 Vandoeuvre-les-Nancy (France)

    2009-03-15

    This paper deals with the online checking of the humidification of a Proton Exchange Membrane Fuel Cell (PEMFC). Indeed, drying or flooding can decrease the performance of the PEMFC and even lead to its destruction. An online humidification diagnosis can allow a real-time control. A good indicator of the membrane humidification state is its internal resistance. As known, the membrane ionic conductivity increases with the membrane water content. This resistance can be calculated at high frequency by dividing the voltage variation by the current variation. The proposed scheme makes use of measurements of current and voltage ripples coming from the association of a static DC-DC converter and the fuel cell. The experiment thus consists in computing the internal resistance in wet and dry conditions. (author)

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

    DEFF Research Database (Denmark)

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

    2003-01-01

    The CO poisoning effect on carbon-supported platinum catalysts (at a loading of 0.5 mg Pt/cm(2) per electrode! in polymer electrolyte membrane fuel cells (PEMFCs) has been investigated in a temperature range from 125 to 200 degreesC with the phosphoric acid-doped polybenzimidazole membranes as el...... and temperature. The effect of CO2 in hydrogen was also studied. At 175 degreesC, 25% CO2 in the fuel stream showed only the dilution effect. (C) 2003 The Electrochemical Society.......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...

  8. 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...

  9. 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.

  10. 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)

  11. Identification and novel adaptive fuzzy control of nonlinear system for PEMFC stack

    Institute of Scientific and Technical Information of China (English)

    WEI Dong; XU Hong; ZHU Xin-jian

    2006-01-01

    The operating temperature of a proton exchange membrane fuel cell stack is a very important control parameter. It should be controlled within a specific range, however, most of existing PEMFC mathematical models are too complicated to be effectively applied to on-line control. In this paper, input-output data and operating experiences will be used to establish PEMFC stack model and operating temperature control system. An adaptive learning algorithm and a nearest-neighbor clustering algorithm are applied to regulate the parameters and fuzzy rules so that the model and the control system are able to obtain higher accuracy. In the end, the simulation and the experimental results are presented and compared with traditional PID and fuzzy control algorithms.

  12. 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)

  13. Graphitised Carbon Nanofibres as Catalyst Support for PEMFC

    DEFF Research Database (Denmark)

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

    2011-01-01

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

  14. 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.

  15. 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)

  16. 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)

  17. 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.

  18. 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

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

    Science.gov (United States)

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

    2010-01-01

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

  1. 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.

  2. 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.

  3. Nafion-stabilised bimetallic Pt–Cr nanoparticles as electrocatalysts for proton exchange membrane fuel cells (PEMFCs)† †Electronic supplementary information (ESI) available. See DOI: 10.1039/c6ra16025e Click here for additional data file.

    Science.gov (United States)

    Gupta, G.; Sharma, S.

    2016-01-01

    The current study investigated the unique combination of alloying (Pt with Cr) and Nafion stabilisation to reap the benefits of catalyst systems with enhanced catalytic activity and improved durability in PEMFCs. Pt–Cr alloy nanoparticles stabilised with Nafion were chosen in the current study owing to their higher stability in acidic and oxidising media at high temperatures compared to other Pt-transition metal alloys (e.g. Pt–Ni, Pt–Co). Two different precursor : reducing agent (1 : 10 and 1 : 20) ratios were used in order to prepare two different alloys, denoted as Pt–Cr 10 and Pt–Cr 20. The Pt–Cr 20 alloy system (with composition Pt80Cr20) demonstrated higher electrocatalytic activity for the oxygen reduction reaction compared to commercial Pt/C (TKK) catalysts. Accelerated stress tests and single cell tests revealed that Nafion stabilised alloy catalyst systems displayed significantly enhanced durability (only ∼20% loss of ECSA) compared with Pt/C (50% loss of ECSA) due to improved catalyst–ionomer interaction. Furthermore, the Pt–Cr 20 alloy system demonstrated a current density comparable to that of Pt/C making them promising potential electrocatalysts for proton exchange membrane fuel cells.

  4. 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

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

    Directory of Open Access Journals (Sweden)

    M. SHAKERI

    2011-06-01

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

  6. 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

  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. 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.

  9. Experimental characterization and numerical modeling of PEMFC stacks designed for different application fields

    Energy Technology Data Exchange (ETDEWEB)

    Jannelli, E.; Minutillo, M. [University of Naples, Parthenope, Centro Direzionale, Naples (Italy); Perna, A. [University of Cassino, Cassino (Italy)

    2011-12-15

    Proton exchange membrane fuel cell (PEMFC) is regarded as a potential future power technology for stationary and mobile applications due to its high efficiency (full and partial load), rapid start-up, high power density, and low emissions. Depending on their particular application field (decentralized combined heat and power production, uninterrupted power supplies (UPS), or mobile applications) different operating conditions and designing parameters are required and different performance can be expected. Thus, the aim of this paper is to investigate the behavior and performance of two stacks of the same size, developed with a different approach according to their application sectors. The first PEMFC stack is designed for UPS units or mobile purpose, the second one, is designed to supply heat and power in residential applications (CHP units). The analysis of the stacks behavior has been carried out by using both experimental and numerical investigations. Experimental results have allowed: (i) to characterize the stacks; (ii) to calibrate the numerical model; (iii) to supply useful data for setting and improving the control system. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  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. Elaboration et optimisation d'électrodes de piles PEMFC à très faible taux de platine par pulvérisation plasma

    OpenAIRE

    Mougenot, Mathieu

    2011-01-01

    This research work has been achieved in the context of the PIE CNRS AMELI-0Pt and AMEPlas and ANR AMADEUS projects and has gathered several entities around the Fuel Cell research: Dreux Agglomération and Agence Innovation Made In Dreux (MID), the French national research laboratories GREMI and LACCO and initially the company MHS Equipment. The project aims at developing and optimising fuel cell electrodes (anode and cathode) for PEMFC (Proton Exchange Membrane Fuel Cell) and SAMFC (Solide Alk...

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

    DEFF Research Database (Denmark)

    He, Ronghuan; Qingfeng, Li; Bjerrum, Niels

    2005-01-01

    Poly(2,5-benzimidazole) (ab-PBI) was prepared from 3,4-diaminobenzoic acid via a polymerisation reaction. The obtained polymer exhibits excellent thermal stability in a temperature range ….. The membrane of ab-PBI when doped with phosphoric acid at room temperaturepresents high proton conductivity...... in a wide temperature range.. The conductivity of the acid doped ab-PBI membranes was studied in a temperature range of 80oC to 200oC under different relative humidity and with different acid doping levels. PEMFC test results indicated that the fuel cell could be operated at temperatures up to 200o......C with phosphoric acid doped ab-PBI as the electrolyte under atmospheric pressure at 200°C without humidification....

  14. 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

  15. 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.

  16. Valores e Desenvolvimento Humano

    NARCIS (Netherlands)

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

    2010-01-01

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

  17. 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.

  18. 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...

  19. Experimental investigation of air relative humidity (RH) cycling tests on MEA/cell aging in PEMFC. Pt. II. Study of low RH cycling test with air RH at 62%/0%

    Energy Technology Data Exchange (ETDEWEB)

    Huang, B.T.; Chatillon, Y.; Bonnet, C.; Lapicque, F. [Laboratoire Reactions et Genie des Procedes, CNRS-Nancy University, Nancy (France); Leclerc, S. [Laboratoire d' Energetique et de Mecanique Theorique et Appliquee, CNRS-Nancy University, Vandoeuvre-les-Nancy (France); Hinaje, M.; Rael, S. [Groupe de Recherche en Electrotechnique et Electronique de Nancy, Nancy University, Vandoeuvre-les-Nancy (France)

    2012-06-15

    The effect of low relative humidity (RH) cycling (RH{sub C} 62%/0%) on the degradation mechanisms of a single proton exchange membrane fuel cell (5 x 5 cm{sup 2}) was investigated and compared to a cell operated at constant humidification (RH{sub C} = 62%). The overall cell performance loss was near 33 {mu}V h{sup -1}, which is greater than the voltage decay under constant RH condition near 3 {mu}V h{sup -1}. The electroactive surface was reduced but to an acceptable level. Impedance spectroscopy revealed that the ohmic and charge transfer resistances were reduced by the likely improved hydration of the ionomeric layer at the catalyst due to hydrogen crossover. This was so important that H{sub 2} starvation was finally responsible for the collapse of the cell after 650 h. Transmission electron microscopy showed occurrence of various phenomena, e.g., bubbles and pinholes formation in the membrane due to local overheat from hydrogen combustion at the cathode, and thickness reduction of catalytic layers. The water up take obtained by {sup 1}H NMR within the membrane electrode assembly (MEA) after low RH cycling reduced by 24% compared to a fresh MEA. Observations are also compared to those obtained at high RH cycling (RH{sub C} 62%/100%) presented in Part I of this study [1]. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  20. Experimental investigation of air relative humidity (RH) cycling tests on MEA/cell aging in PEMFC. Pt. I. Study of high RH cycling test with air RH at 62%/100%

    Energy Technology Data Exchange (ETDEWEB)

    Huang, B.T.; Chatillon, Y.; Bonnet, C.; Lapicque, F. [Laboratoire Reactions et Genie des Procedes, CNRS-Nancy University, Nancy (France); Leclerc, S. [Laboratoire d' Energetique et de Mecanique Theorique et Appliquee, CNRS-Nancy University, Vandoeuvre-les-Nancy (France); Hinaje, M.; Rael, S. [Groupe de Recherche en Electrotechnique et Electronique de Nancy, CNRS-Nancy University, Vandoeuvre-les-Nancy (France)

    2012-06-15

    The effect of high air relative humidity (RH) cycling (RH{sub C} 62%/100%) on the degradation mechanisms of a single (5 x 5 cm{sup 2}) proton exchange membrane fuel cells was investigated. The cell performance was compared to a cell operated at constant humidification (RH{sub C} = 62%). Runs were conducted over approximately 1,500 h at 0.3 A cm{sup -2}. The overall loss in cell performance for the high RH cycling test was 12 {mu}V h{sup -1} whereas it was at 3 {mu}V h{sup -1} under constant humidification. Impedance spectroscopy reveals that the ohmic and charge transfer resistances were little modified in both runs. H{sub 2} crossover measurement indicated that both high RH cycling and constant RH test did not promote serious effect on gas permeability. The electroactive surface loss for anode and cathode during high air RH cycling was more significant than at constant RH operation. The water uptake determined by {sup 1}H nuclear magnetic resonance within the membrane electrode assembly (MEA) after high RH cycling was reduced by 12% in comparison with a fresh MEA. Transmission electron microscopy showed bubbles and pinholes formation in the membrane, catalyst particles agglomeration (also observed by X-ray diffraction), catalyst particles migration in the membrane and thickness reduction of the catalytic layers. Scanning electron microscopy was conducted to observe the changes in morphology of gas diffusion layers after the runs. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  1. 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.

  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. Effects of NOx and SO2 in cathode stream on the performance of PEMFC

    Institute of Scientific and Technical Information of China (English)

    杨代军; 马建新; 周伟; 马晓伟; 邬敏忠; 徐麟; 万钢

    2006-01-01

    The effects of NOx(in a ratio of NO:NO2 = 9:1) and SO2 in cathode stream on the performance of a single proton exchange membrane fuel cell (PEMFC) were investigated. NOx with concentrations of 1×10-3% (in volume, the same as follows), 1.4×10-2% and 1×10-3% could cause significant detrimental effects on the cell performance. However, nearly complete recovery of the cell performance could be observed after NOx was shut off and purged with clean air. The electrochemical measurements suggested that the impacts of NOx resulted mainly from the superposition of the oxygen reduction reaction (ORR),NO and HNO2 oxidation reactions, and the increased cathodic impedance. Trace SO2 with concentrations of 5 × 10-6%, 5 ×10-3%, 2 × 10-4% and 3.2 × 10-4% influenced the cell much severer, which could be attributed to its strong adsorption on the surface of Pt atoms. The cell performance could not be completely recovered after purged with clean air and cyclic voltammetry (CV) tests, due to the changes of electrochemical impedance spectroscopy (ELS) and electrochemical active surface (EAS) caused by surface state change after SO2 exposure.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2008-07-01

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

  6. High temperature polymer electrolyte membrane fuel cells

    DEFF Research Database (Denmark)

    This book is a comprehensive review of high-temperature polymer electrolyte membrane fuel cells (PEMFCs). PEMFCs are the preferred fuel cells for a variety of applications such as automobiles, cogeneration of heat and power units, emergency power and portable electronics. The first 5 chapters...

  7. 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)

  8. 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.

  9. 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

  10. 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 ...

  11. 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...

  12. 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.

  13. 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)

  14. 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.

  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. “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.

  17. Effect of channel arrangement on fluid flow in PEMFC flow field using serpentine channel system with trapezoidal cross-section

    Energy Technology Data Exchange (ETDEWEB)

    Sun, L.; Oosthuizen, P.H. [Queen' s Univ., Kingston, ON (Canada). Dept. of Mechanical and Materials Engineering; McAuley, K.B. [Queen' s Univ., Kingston, ON (Canada). Dept. of Chemical Engineering

    2005-07-01

    Developments in Computational Flow Dynamics (CFD) software have meant that Proton Exchange Membrane Fuel Cell (PEMFC) modelling is now able to include cell components such as gas channels and porous diffusion layers. This paper discussed a numerical model which was developed to study air flow in the flow plate and gas diffusion layer assembly on the cathode side of a PEMFC. The flow plate in this fuel cell often has serpentine channels, and the porous layer is adjacent to the flow plate in order to diffuse the air to the catalyst layer. Flow crossover of air through the porous diffusion layer from one part of the channel to another can occur as a result of pressure differences between different parts of the channel. The numerical study was undertaken to compare the cases of a single channel and 2 parallel channels, with the channels having a trapezoidal cross-sectional shape. The objective of the study was to examine the effect of the flow plate geometry on the basic fluid flow through the plate. Flow was assumed to be 3-dimensional, steady, incompressible, isothermal and single-phase. The flow through the porous diffusion layer was described using the Darcy model. Dimensionless governing equations were solved using FIDAP, a commercial CFD solver. The results indicate that single channel systems have a greater maximum flow rate difference than the parallel channel systems under the conditions considered in the experiment. In addition, the size ratio R of trapezoidal cross-sectional shape has a significant effect on the flow crossover and pressure variation in the flow field. 16 refs., 15 figs.

  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. Impasses do desenvolvimento

    Directory of Open Access Journals (Sweden)

    Yilmaz Akyüz

    2005-07-01

    Full Text Available Este artigo fornece um panorama dos principais impasses que se impõem aos países em desenvolvimento no que diz respeito à industrialização e ao comércio internacional. O autor examina os matizes envolvidos nas estratégias de incremento da exportação de produtos manufaturados e argumenta que a retomada do crescimento regional requer apoio não apenas de políticas voltadas para esse setor, mas também de acordos monetários e de cooperação destinados a garantir a estabilidade dos mercados.This article focuses on the main aspects concerning trade, foreign direct investment and industrialization in developing countries. The author states that a return to stable and rapid regional growth needs to be underpinned not only by policies directed at the upgrading of production and exports, but also by accompanying regional monetary arrangements and cooperation designed to ensure the stability of financial markets.

  20. Dynamic behaviour of fuel cells

    OpenAIRE

    Weydahl, Helge

    2006-01-01

    This thesis addresses the dynamic behaviour of proton exchange membrane fuel cells (PEMFCs) and alkaline fuel cells (AFCs). For successful implementation in automotive vehicles and other applications with rapidly varying power demands, the dynamic behaviour of the fuel cell is critical. Knowledge of the load variation requirements as well as the response time of the cell at load change is essential for identifying the need for and design of a buffer system.The transient response of a PEMFC su...

  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. CAPITAL SOCIAL, DEMOCRACIA E DESENVOLVIMENTO

    Directory of Open Access Journals (Sweden)

    Luciene Dal Ri

    2011-12-01

    Full Text Available Este artigo apresenta uma revisão critica da literatura sobre a relação entre Capital Social, Democracia e o Desenvolvimento. É relevante refletirmos sobre estes três temas, pois não se consegue ver um distanciamento entre ambos. Todavia, como meio para promover o capital social, o desenvolvimento e a democracia, é necessária que haja uma melhoria do bem-estar social, devendo ser associada com liberdades econômicas e abertura de mercado de modo a viabilizar o crescimento econômico e a melhoria na qualidade de vida da população.

  4. 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)

  5. 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.

  6. 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)

  7. 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.

  8. 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...

  9. 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.

  10. 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...

  11. 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...

  12. 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.

  13. 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)

  14. 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.

  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. Analysis of oxygen sources and reaction pathways of carbon support corrosion at the cathode in PEMFC using oxygen-18 DEMS

    Energy Technology Data Exchange (ETDEWEB)

    Li Wei [Department of Chemical and Biological Engineering, University of Alabama, Box 870203, Tuscaloosa AL 35487-0203 (United States); Lane, Alan M., E-mail: alane@eng.ua.ed [Department of Chemical and Biological Engineering, University of Alabama, Box 870203, Tuscaloosa AL 35487-0203 (United States)

    2010-09-01

    Oxygen gas, water used to humidify the gases, and surface oxides originated from the carbon black and catalyst preparation are the three possible oxygen sources contributing to carbon support corrosion (CSC) at the cathode in proton exchange membrane fuel cells (PEMFC). To discriminate among them, oxygen was isotopically labeled by replacing regular water with oxygen-18 ({sup 18}O) enriched water (H{sub 2}{sup 18}O, 98%) in differential electrochemical mass spectrometry (DEMS). The DEMS spectra of the cathode exhaust gases O{sub 2}, O{sup 18}O, {sup 18}O{sub 2}, CO{sub 2}, CO{sup 18}O and C{sup 18}O{sub 2} (m/z equal to 32, 34, 36, 44, 46 and 48 correspondingly), sampled by a mass spectrometer during cyclic voltammetry (potential cycled for 100-1400 mV at the rate of 10 mV s{sup -1}) and chronoamperometry, were analyzed to identify the sources of oxygen, identify mechanistic pathways, and classify the surface oxides on carbon for CSC. It was found that water is the main direct oxygen source for CSC. Water reacts with carbon to produce at least three types of carbon surface oxides, which are then further oxidized with water to produce CO{sub 2} in different potential ranges.

  17. 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.

  18. 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.

  19. 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.

  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. 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...

  2. 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...

  3. 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.)

  4. 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...

  5. 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...

  6. 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.

  7. 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.

  8. 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

  9. 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.

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

    DEFF Research Database (Denmark)

    Andersen, Shuang Ma

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

  11. 电解重整式甲醇燃料电池系统%PEMFC system incorporating a methanol electrolytic reformer

    Institute of Scientific and Technical Information of China (English)

    李庆; 叶强; 杨晓光

    2013-01-01

    为解决直接甲醇燃料电池中甲醇氧化活性低及甲醇穿透问题,提出一种新型的电解重整式甲醇燃料电池系统.在系统中,高温电解重整器重整甲醇为常温燃料电池供氢,燃料电池的部分电能供给电解重整器使用.通过对系统的物料流、焓流、有效能流的分析,确定了系统中的不可逆因素.结果表明:电解重整器电压是影响系统效率的重要参数;升高重整器温度可以显著降低其电压,但必须采用合理的压力、甲醇溶液浓度以抑制甲醇溶液的蒸发,降低热量损失.与传统的直接甲醇燃料电池系统以及高温甲醇热重整联合质子交换膜燃料电池系统相比,该系统性能较高、结构紧凑.%Slow rate of methanol oxidation and its crossover are two major challenges for direct methanol fuel cells (DMFC). The sluggish kinetics can be relieved by elevating cell temperature which, however, leads to other problems like membrane dehydration. To solve these problems, it is proposed that a methanol electrolytic reformer ( MER) is combined with polymer electrolyte membrane fuel cell (PEMFC) system. Working at elevated temperature, the MER provides hydrogen for the PEMFC and is driven by power provided by the PEMFC. Essential components included in this system are described and flows of mass, enthalpy and exergy are presented. Thermodynamic analysis shows that exergy destructions occur in main components, i.e. , PEMFC and MER. The voltage of MER is an important parameter influencing the efficiency of the system. Rising temperature in MER, MER voltage required significantly decreases, but exergy losses caused by heat dissipation and heat transfer increase exponentially due to the intensified evaporation of methanol solution. To mitigate evaporation, low methanol concentration and high pressure could be necessary. When MER works at higher methanol concentration, higher pressure is required for efficient operation. The overall performance

  12. 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.

  13. 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)

  14. Effectiveness of heat-integrated methanol steam reformer and polymer electrolyte membrane fuel cell stack systems for portable applications

    Science.gov (United States)

    Lotrič, A.; Sekavčnik, M.; Hočevar, S.

    2014-12-01

    Efficiently combining proton exchange membrane fuel cell (PEMFC) stack with methanol steam reformer (MSR) into a small portable system is still quite a topical issue. Using methanol as a fuel in PEMFC stack includes a series of chemical processes where each proceeds at a unique temperature. In a combined MSR-PEMFC-stack system with integrated auxiliary fuel processors (vaporizer, catalytic combustor, etc.) the processes are both endothermic and exothermic hence their proper thermal integration can help raising the system efficiency. A concept of such fully integrated and compact system is proposed in this study. Three separate systems are designed based on different PEMFC stacks and MSR. Low-temperature (LT) and conventional high-temperature (cHT) PEMFC stack characteristics are based on available data from suppliers. Also, a novel high-temperature (nHT) PEMFC stack is proposed because its operating temperature coincides with that of MSR. A comparative study of modelled systems is performed using a mass and energy balances zero-dimensional model, which is interdependently coupled to a physical model based on finite element method (FEM). The results indicate that a system with nHT PEMFC stack is feasible and has the potential to reach higher system efficiencies than systems with LT or cHT PEMFC stacks.

  15. 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...

  16. Comparative analysis of the electroactive area of Pt/C PEMFC electrodes in liquid and solid polymer contact by underpotential hydrogen adsorption/desorption

    Energy Technology Data Exchange (ETDEWEB)

    Chaparro, A.M.; Martin, A.J.; Folgado, M.A.; Gallardo, B. [Dep. de Energia, CIEMAT, Avda. Complutense, 22, 28040 Madrid (Spain); Daza, L. [Dep. de Energia, CIEMAT, Avda. Complutense, 22, 28040 Madrid (Spain); Instituto de Catalisis y Petroleoquimica (CSIC), Marie Curie 2, Campus Cantoblanco, 28049 Madrid (Spain)

    2009-06-15

    Because of the different experimental conditions found in literature for the measurement of the electroactive area of Pt/C electrodes of proton exchange membrane fuel cells (PEMFC) by means of underpotential hydrogen adsorption (H{sub UPD}) voltammetry, specially concerning sweep rate and temperature, it was found necessary to perform an analysis of these parameters. With this aim, the electroactive area of PEMFC electrodes has been measured by means of H{sub UPD} voltammetry at different sweep rates and temperatures, in liquid electrolyte and solid polymer contact. Both configurations show that H{sub UPD} adsorption and desorption charges are strongly dependent on sweep rate voltage and temperature. The most common behaviour observed is a maximum in H{sub UPD} desorption charge, typically in the 100-10 mV s{sup -1} sweep rate range, whereas H{sub UPD} adsorption charge shows continuous increase with decreasing sweep rate. The decrease of desorption charge at low sweep rates is attributed to adsorbing species related with carbon support reactivity. These processes are also responsible for the increase in desorption H{sub UPD} charge at low sweep rate. At high sweep rate, both adsorption and desorption H{sub UPD} charges decrease due to limiting diffusion of protons through the microporous electrode. As a consequence, it is found that the closest approximation to the real electroactive area (i.e. the area accessible to protons) corresponds to the maximum in the H{sub UPD} desorption charge in the range of 10-100 mV s{sup -1} sweep rate. The influence of measuring temperature is also tested in the range 25 C-80 C. A dependence of the adsorption and desorption hydrogen charges is found, due to thermodynamic and kinetics factors. We observe that the processes competing with hydrogen adsorption, i.e. generation and adsorption of carbon species are enhanced with temperature, so a low measuring temperature is found as most appropriate. (author)

  17. 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)

  18. 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.

  19. 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...

  20. 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.

  1. 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.

  2. 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)

  3. 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.

  4. 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

  5. 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.

  6. A teoria do “desenvolvimento fragmentador”

    Directory of Open Access Journals (Sweden)

    Fred Scholz

    2010-04-01

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

  7. 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...

  8. 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...

  9. 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

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

    Directory of Open Access Journals (Sweden)

    Samantha Nunest

    2010-01-01

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

  11. 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)

  12. 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

  13. 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...

  14. An air-breathing single cell small proton exchange membrane fuel cell system with AB5-type metal hydride and an ultra-low voltage input boost converter

    Science.gov (United States)

    Akiyama, Kazuya; Matsumoto, Satoshi; Miyasaka, Akihiro; Shodai, Takahisa

    A new strategy for increasing the power density of an air-breathing small proton exchange membrane fuel cell (PEMFC) system for the main energy source of portable consumer electronics is presented. The small PEMFC system is composed of a single cell. Utilizing the output voltage of the single cell, we introduce a newly designed ultra-low voltage input boost converter. The boost converter can generate 4.1 V output from input sources with low voltage ranges, such as under 1.0 V. The cathode plate is made from a thin SUS 316L stainless steel plate and has ribs that prevent the cathode from bending. The hydrogen is supplied by a metal hydride (MH) tank cartridge. The MH tank contains highly packed AB5-type MH. The MH tank cartridge has a volume of 13.2 cm 3 and can absorb 6.7 L of hydrogen. The maximum power of the small PEMFC is 4.42 W at room temperature. Using 6.7 L of hydrogen, the small PEMFC can generate 11 Wh of electricity. The power density of the small PEMFC reaches 0.51 Wh cm -3. And the power density of the whole small PEMFC system, which contains the boost converter, a small Li-ion battery for a load absorber, and a case for the system, reaches 0.14 Wh cm -3. This value matches that of external Li-ion battery chargers for cell phones. We installed the small PEMFC system in a cell phone and confirmed the operations of calling, receiving, videophone, connecting to the Internet, and watching digital TV. And also confirmed that the small PEMFC system provides approximately 8.25 h of talk time, which is about three times as long as that for the original Li-ion battery.

  15. Electrochemical impedance spectroscopy and cyclic voltammetry studies of a proton exchange membrane fuel cell operated at low humidity conditions

    Energy Technology Data Exchange (ETDEWEB)

    Malevich, D. [Fuel Cell Research Centre, Kingston, ON (Canada)

    2007-07-01

    This study investigated water balance issue in polymer electrolyte membrane fuel cells (PEMFCs) using electrochemical impedance spectroscopy (EIS) and cyclic voltammetry. Equivalent PEMFC circuits and microporous layers (MPL) were investigated. Bode and Nyquist plots were presented, and the effect of current density on EIS was explored. Membrane resistance, Warburg resistance, and electron transfer resistance was measured. The study also examined hydrogen underpotential deposition on platinum. Cyclic voltammetry was used to develop curves for electrochemically active surfaces and charge transfer resistance of the MPL. Polarization curves for the anode and cathode MPLs were presented along with impedance diagrams for the PEMFC operating at low humidity conditions. tabs., figs.

  16. Platinum Porous Electrodes for Fuel Cells

    DEFF Research Database (Denmark)

    Andersen, Shuang Ma

    Fuel cell energy bears the merits of renewability, cleanness and high efficiency. Proton Exchange Membrane Fuel Cell (PEMFC) is one of the most promising candidates as the power source in the near future. A fine management of different transports and electrochemical reactions in PEM fuel cells...... to a genuine picture of a working PEM fuel cell catalyst layer. These, in turn, enrich the knowledge of Three-Phase-Boundary, provide efficient tool for the electrode selection and eventually will contribute the advancement of PEMFC technology....

  17. 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.

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

    Science.gov (United States)

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

    2012-01-01

    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

  19. 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.

  20. 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.

  1. 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...

  2. 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.)

  3. 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.

  4. 小功率PEMFC移动式电源的箱体结构和造型设计%Box Structure and Modeling Design of Transportation Power of Small Power PEMFC

    Institute of Scientific and Technical Information of China (English)

    贾秋红; 韩明; 邓斌; 张财志; 廖林清

    2011-01-01

    小功率质子交换膜燃料电池是目前质子交换膜燃料电池的研究热点之一,通过三维实体造型设计,使箱体结构设计达到灵活、实用、可靠和便捷等目的,以小功率自行车用燃料电池为主要应用目标,对采用高压氢气瓶、小型金属氢化物储气罐等不同氢气供气方式下的小功率质子交换膜燃料电池进行箱体结构和造型设计,使其既能在通用供气方式下作为一个独立的部件进行供电,也能快速安装金属氢化物储气罐箱体进行移动电源和便携式装置的供电,实现了使用的可靠性、灵活性和便捷性。%The research of small power PEMFC is one of research focus for PEMFC.By three dimensional solid modeling design of fuel cell box,it will make structure design more flexible,practical,reliable and portable,and help to its widely application in small electrical equipment and transportation etc fields.In this article,it takes the small power bike with fuel cells as the main application target.Based on different two hydrogen supply methods,high-pressure hydrogen cylinders and portable metal hydride hydrogen cylinders,the box structure and shape design of small power PEMFC is made.It cannot only provide power as a independent component using high-pressure hydrogen cylinders supply gas equipment,but also as transportation power or portable equipment by installing rapidly metal hydride hydrogen storage cylinders,which realized the use of reliability,flexibility and convenience.

  5. 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...

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

    Energy Technology Data Exchange (ETDEWEB)

    K. J. Berry; Susanta Das

    2009-12-30

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

  7. 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.)

  8. 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-...

  9. 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

  10. Robust DC/DC converter control for polymer electrolyte membrane fuel cell application

    Science.gov (United States)

    Wang, Ya-Xiong; Yu, Duck-Hyun; Chen, Shi-An; Kim, Young-Bae

    2014-09-01

    This study investigates a robust controller in regulating the pulse width modulation (PWM) of a DC/DC converter for a polymer electrolyte membrane fuel cell (PEMFC) application. A significant variation in the output voltage of a PEMFC depends on the power requirement and prevents a PEMFC from directly connecting to a subsequent power bus. DC/DC converters are utilized to step-up or step-down voltage to match the subsequent power bus voltage. In this study, a full dynamic model, which includes a PEMFC and boost and buck DC/DC converters, is developed under MATLAB/Simulink environment for control. A robust PWM duty ratio control for the converters is designed using time delay control (TDC). This control enables state variables to accurately follow the dynamics of a reference model using time-delayed information of plant input and output information within a few sampling periods. To prove the superiority of the TDC performance, traditional proportional-integral control (PIC) and model predictive control (MPC) are designed and implemented, and the simulation results are compared. The efficacies of TDC for the PEMFC-fed PWM DC/DC converters are validated through experimental test results using a 100 W PEMFC as well as boost and buck DC/DC converters.

  11. 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)

  12. 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...

  13. 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 ...

  14. 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.

  15. 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

  16. 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

  17. 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.

  18. 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.

  19. Study of performance of PEMFC stack in different electrode positions%基于不同电极位置的PEMFC运行特性研究

    Institute of Scientific and Technical Information of China (English)

    欧阳旭; 贾俊波; 李奇

    2012-01-01

    Proton exchange membrane (PEM) fuel cell is an electrochemical generating device which has great potential of development, particularly suitable for a new generation of portable power and electric vehicle power source. Water is the key factor of affecting fuel cell performance. Water management plays an important role in PEM fuel cell for safe and steady operation. The stack uses an air fan in the edge of the cathode, combining high oxidant supply and stack cooling purposes. In this paper, the performance of a PEM fuel cell and mass transport was observed in different electrode relative position. The results show, the different electrode relative positions do not affect the performance of PEM fuel cell in low current density. When PEM fuel cell is placed anode-upward, gravity is advantageous to discharge the liquid water in PEM fuel cell cathode in high current density.%质子交换膜燃料电池(PEMFC)是一种有巨大发展潜力的发电装置,特别适合成为新一代便携式电源和电动汽车的动力源.水是影响燃料电池性能的关键因素,良好的水管理是使其安全稳定运行和提高其性能的必要条件.在PEM燃料电池的阴极侧安装风扇,向燃料电池提供氧化剂和降低电池温度,通过实验,观察到在电池堆方向发生变化的情况下,PEM燃料电池性能及其内部传质情况会发生明显变化.实验结果发现:当电流密度较小时,电极方向对PEM燃料电池的性能影响不明显;当电流密度较大时,阳极在上、阴极在下时燃料电池性能优于阴极在上、阳极在下的燃料电池性能.

  20. 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

  1. 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.

  2. Equivalent Circuit Parameters Estimation for PEM Fuel Cell Using RBF Neural Network and Enhanced Particle Swarm Optimization

    Directory of Open Access Journals (Sweden)

    Wen-Yeau Chang

    2013-01-01

    Full Text Available This paper proposes an equivalent circuit parameters measurement and estimation method for proton exchange membrane fuel cell (PEMFC. The parameters measurement method is based on current loading technique; in current loading test a no load PEMFC is suddenly turned on to obtain the waveform of the transient terminal voltage. After the equivalent circuit parameters were measured, a hybrid method that combines a radial basis function (RBF neural network and enhanced particle swarm optimization (EPSO algorithm is further employed for the equivalent circuit parameters estimation. The RBF neural network is adopted such that the estimation problem can be effectively processed when the considered data have different features and ranges. In the hybrid method, EPSO algorithm is used to tune the connection weights, the centers, and the widths of RBF neural network. Together with the current loading technique, the proposed hybrid estimation method can effectively estimate the equivalent circuit parameters of PEMFC. To verify the proposed approach, experiments were conducted to demonstrate the equivalent circuit parameters estimation of PEMFC. A practical PEMFC stack was purposely created to produce the common current loading activities of PEMFC for the experiments. The practical results of the proposed method were studied in accordance with the conditions for different loading conditions.

  3. 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...

  4. 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.

  5. 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.

  6. 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...

  7. 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...

  8. Biotecnologia aplicada ao desenvolvimento de vacinas

    Directory of Open Access Journals (Sweden)

    Mariana de Oliveira Diniz

    2010-01-01

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

  9. 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...

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2004-07-01

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

  11. 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.

  12. 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...

  13. 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].

  14. 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.

  15. Effect of gas composition and gas utilisation on the dynamic response of a proton exchange membrane fuel cell

    Science.gov (United States)

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

    The transient response of a proton exchange membrane fuel cell (PEMFC) was measured for various cathode gas compositions and gas utilisations (fraction of supplied reactant gas which is consumed in the fuel cell reaction). For a PEMFC operated on pure hydrogen and oxygen, the cell voltage response to current steps was fast, with response times in the range 0.01-1 s, depending on the applied current. For a PEMFC supplied with air as cathode gas, an additional relaxation process related to oxygen transport caused a slower response (approximately 0.1-2 s depending on the applied current). Response curves up to approximately 0.01 s were apparently unaffected by gas composition and utilisation and were most likely dominated by capacitive discharge of the double layer and reaction with surplus oxygen residing in the cathode. The utilisation of hydrogen had only a minor effect on the response curves, while the utilisation of air severely influenced the PEMFC dynamics. Results suggested that air flow rates should be high to obtain rapid PEMFC response.

  16. 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.

  17. 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.

  18. 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

  19. Impact of the European Union vehicle waste directive on end-of-life options for polymer electrolyte fuel cells

    Science.gov (United States)

    Handley, C.; Brandon, N. P.; van der Vorst, R.

    Polymer electrolyte membrane fuel cells (PEMFCs) may well be powering millions of cars by 2020. At its end-of-life, each car will have a redundant PEMFC stack. The EU vehicle waste directive sets tough recycling and re-use requirements for the cars of the future. The criteria for assessing the end-of-life options are based on technical, economic and environmental feasibility. The optimum strategy will require stack dismantling and separation of the major components. Steel and aluminium parts can enter the general recycling stream, but the membrane electrode assembly and bipolar plates will require a specialised recycling process. One option is to shred the MEA, dissolve and recover the membrane, burn off the carbon, and recycle the platinum and ruthenium catalysts using solvent extraction. The heaviest part of the PEMFC stack is the bipolar plates. If carbon fibre based, the bipolar plates could enter a fluidised bed recovery process where the constituent materials are recovered for re-use. The EU vehicle waste directive sets high recycling targets based on weight, and thus it is strongly advisable for the relatively heavy bipolar plates to be recycled, even though energy recovery by incineration may be a cheaper and possible more environmentally benign option. The EU vehicle directive will put pressure on the end-of-life options for the PEMFC stack to be weighted towards recycling and re-use; it will have a significant impact on the design and end-of-life options for the PEMFC. The overall effect of this pressure on the end-of-life treatment of the PEMFC and the consequential contribution to environmental life cycle impacts is discussed. It is concluded that a range of external pressures influence the selection of a suitable end-of-life management strategy, and while opportunities for re-use of components are limited, all components of the PEMFC stack could in principle be recycled.

  20. 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)

  1. 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)

  2. 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

  3. 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

  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. 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.

  6. 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,...

  7. 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)

  8. 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...

  9. 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...

  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. 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...

  12. 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.

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

    DEFF Research Database (Denmark)

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

    2013-01-01

    (normally carbon black) is one of the essential degradation mechanisms during cell operation. In this work, durability of Carbon Nanofibers (CNF) & Carbon Nanotubes (CNT) as alternative platinum catalyst supports for Proton Exchange Membrane Fuel Cells (PEMFCs) was assessed. Platinized CNF and CNT using...... a standard polyol method were prepared and fabricated as cathodes of Membrane Electrode Assemblies (MEA) for PEMFC. Both the catalysts as such and the MEAs made out of them were evaluated regarding to thermal and electrochemical stability using traditional carbon black (Vulcan XC72) as a reference. Thermal...... gravimetric analysis (TGA), cyclic voltammetry (CV), polarization curve and impedance spectroscopy were applied on the samples under accelerated stress conditions. The carbon nano-materials demonstrated better stability as support for nano-sized platinum catalyst under PEMFC related operating conditions. Due...

  14. Pseudo-2D model of a cross-flow membrane humidifier for a PEM fuel cell under multiphase conditions

    Energy Technology Data Exchange (ETDEWEB)

    Dalet, C.; Diny, M. [Peugeot Citroen Automobile, Carrieres sous Poissy (France). Fuel Cell Program; Maranzana, G.; Lottin, O.; Dillet, J. [Nancy Univ., Vanoeuvre les Nancy (France). Centre national de la recherche scientifique

    2009-07-01

    Membrane dehydration can reduce the performance of proton exchange membrane fuel cells (PEMFCs). However, excessive water at the inlet of the fuel cells can flood cathodes. An understanding of the coupled mass and heat transfer processes involved in membrane humidifiers is needed in order to successfully manage water in PEMFCs. This paper discussed a pseudo-2D model of a cross-flow membrane humidifier for PEMFCs. The model was used to test correlations of the water transport coefficient through a Nafion 115 membrane. The study showed that results obtained using the model differed from experimental results. The effects of inlet operating conditions, flow rates, and temperature on the performance of a planar membrane humidifier under both single- and multi-phase conditions were also investigated.

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

    DEFF Research Database (Denmark)

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

    2015-01-01

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

  16. 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.

  17. Control-oriented dynamic fuzzy model and predictive control for proton exchange membrane fuel cell stack

    Institute of Scientific and Technical Information of China (English)

    LI Xi; DENG Zhong-hua; CAO Guang-yi; ZHU Xin-jian; WEI Dong

    2006-01-01

    Proton exchange membrane fuel cell (PEMFC) stack temperature and cathode stoichiometric oxygen are very important control parameters. The performance and lifespan of PEMFC stack are greatly dependent on the parameters. So, in order to improve the performance index, tight control of two parameters within a given range and reducing their fluctuation are indispensable.However, control-oriented models and control strategies are very weak junctures in the PEMFC development. A predictive control algorithm was presented based on their model established by input-output data and operating experiences. It adjusts the operating temperature to 80 ℃. At the same time, the optimized region of stoichiometric oxygen is kept between 1.8-2.2. Furthermore, the control algorithm adjusts the variants quickly to the destination value and makes the fluctuation of the variants the least. According to the test results, compared with traditional fuzzy and PID controllers, the designed controller shows much better performance.

  18. 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...

  19. Desenvolvimento de conjunto membrana-eletrodos para célula a combustível de metanol direto passiva Development of membrane electrode assembly for passive direct methanol fuel cell

    Directory of Open Access Journals (Sweden)

    Eli Carlos Lisboa Ferreira

    2010-01-01

    Full Text Available Direct methanol fuel cells (DMFCs without external pumps or other ancillary devices for fuel and oxidant supply are known as passive DMFCs and are potential candidates to replace lithium-ion batteries in powering portable electronic devices. This paper presents the results obtained from a membrane electrode assembly (MEA specifically designed for passive DMFCs. Appropriated electrocatalysts were prepared and the effect of their loadings was investigated. Two types of gas diffusion layers (GDL were also tested. The influence of the methanol concentration was analyzed in each case. The best MEA performance presented a maximum power density of 11.94 mW cm-2.

  20. 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

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

    DEFF Research Database (Denmark)

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

    2003-01-01

    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. A high temperature PEMFC system operational at up to 200°C is demonstrated with no gas......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 in the field is alternative polymer electrolytes for operation above 100°C. As one of the successful approaches...

  2. 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.

  3. 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

  4. 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.

  5. 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

  6. Electrode porosity and effective electrocatalyst activity in electrode-membrane-assemblies (MEAs) of PEMFCs

    Energy Technology Data Exchange (ETDEWEB)

    Fischer, A.; Wendt, H. [Institut fuer Chemische Technologie, Darmstadt (Germany)

    1996-12-31

    New production technologies of membrane-electrode-assemblies for PEWCs which ensure almost complete catalyst utilization by {open_quotes}wetting{close_quotes} the internal catalyst surface with the ionomeric electrolyte, allow for a reduction of Pt-loadings from prior 4 mg cm{sup -2} to now less than 0.5 mg cm{sup -2}. Such electrodes are not thicker than from 5 to 10 {mu}m. Little has been published hitherto about the detailed micromorphology of such electrodes and the role of electrode porosity on electrode performance. It is well known, that the porosity of thicker fuel cell electrodes, e.g. of PAFC or AFC electrodes is decisive for their performance. Therefore the issue of this investigation is to measure and to modify the porosity of electrodes prepared by typical MEA production procedures and to investigate the influence of this porosity on the effective catalyst activity for cathodic reduction of oxygen from air in membrane cells. It may be anticipated that any mass transfer hindrance of gaseous reactants into porous electrodes would manifest itself rather in the conversion of dilute gases than in the conversion of pure gases (e.g. neat oxygen). Therefore in this investigation the performance of membrane cell cathodes with non pressurized air had been compared to that with neat oxygen at cathodes which had a relatively low Pt-loading of 0.15 mg cm{sup -2}.

  7. 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.

  8. 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.

  9. 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

  10. 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)

  11. 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.

  12. 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

  13. 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

  14. 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)

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

    DEFF Research Database (Denmark)

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

    2003-01-01

    The CO poisoning effect on carbon-supported platinum catalysts in polymer electrolyte membrane fuel cells has been investigated in a temperature range from 125 to 200°C with the phosphoric acid-doped polybenzimidazole membranes as electrolyte. The effect is very temperature-dependent and can be s...... densities lower than 0.25 A/cm2. For comparison, the tolerance is only 0.0025 % CO (25 ppm) at 80°C at current densities up to 0.15 A/cm². The effect of CO2 in hydrogen was also studied. At 175°C, 25% CO2 in the fuel stream showed only the dilution effect.......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...

  16. Electrochemical Performance Measurements of PBI-Based High-Temperature PEMFCs

    Directory of Open Access Journals (Sweden)

    Javier Parrondo

    2011-01-01

    Full Text Available Acid-doped poly(2,2′-m-phenylene-5,5′-bibenzimidazole membranes have been prepared and used to assemble membrane electrode assemblies (MEAs with various contents of PBI (1–30 wt.% in the gas diffusion electrode (GDE. The MEAs were tested in the temperature range of 140∘C–200∘C showing that the PBI content in the electrocatalyst layer influences strongly the electrochemical performance of the fuel cell. The MEAs were assembled using polyphosphoric acid doped PBI membranes having conductivities of 0.1 S cm−1 at 180∘C. The ionic resistance of the cathode decreased from 0.29 to 0.14 Ohm-cm2 (180∘C when the content of PBI is varied from 1 to 10 wt.%. Similarly, the mass transfer resistance or Warburg impedance increased 2.5 times, reaching values of 6 Ohm-cm2. 5 wt.% PBI-based MEA showed the best performance. The electrochemical impedance measurements were in good agreement with the fuel cell polarization curves obtained, and the optimum performance was obtained when overall resistance was minimal.

  17. Thermodynamic and chemical kinetic analysis of a 5 kw, compact steam reformer - PEMFC system

    Energy Technology Data Exchange (ETDEWEB)

    Acevedo, Luis Evelio Garcia; Oliveira, Amir Antonio Martins [Universidade Federal de Santa Catarina (UFSC), Florianopolis, SC (Brazil). Dept. de Engenharia Mecanica], e-mail: evelio@labcet.ufsc.br, e-mail: amirol@emc.ufsc.br

    2006-07-01

    Here we present a thermodynamic and chemical kinetic analysis of the methane steam reforming for production of 5 kw of electrical power in a PEM fuel cell. The equilibrium analysis is based on the method of element potentials to find the state of minimum Gibbs free energy for the system and provides the equilibrium concentration of the reforming products. The objective of this analysis is to obtain the range of reforming temperature, pressure and steam-methane molar ratio that results in maximum hydrogen production subjected to low carbon monoxide production and negligible coke formation. The thermal analysis provides the heat transfer rates associated with the individual processes of steam production, gas-phase superheating and reforming necessary to produce 5 kw of electrical power in a PEM fuel cell and allows for the calculation of thermal efficiencies. Then, the chemical reaction pathways for hydrogen production in steam reforming are discussed and the available chemical, adsorption and equilibrium constants are analyzed in terms of thermodynamic consistency. This analysis provides the framework for the reactor sizing and for establishing the adequate operation conditions. (author)

  18. 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.

  19. 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.

  20. 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)

  1. A review of the development of high temperature proton exchange membrane fuel cells

    Institute of Scientific and Technical Information of China (English)

    Suthida Authayanun; Karittha Im-orb; Amornchai Arpornwichanop

    2015-01-01

    Due to the need for clean energy, the development of an efficient fuel cell technology for electricity generation has received considerable attention. Much of the current research efforts have investi‐gated the materials for and process development of fuel cells, including the optimization and simpli‐fication of the fuel cell components, and the modeling of the fuel cell systems to reduce their cost and improve their performance, durability and reliability to enable them to compete with the con‐ventional combustion engine. A high temperature proton exchange membrane fuel cell (HT‐PEMFC) is an interesting alternative to conventional PEMFCs as it is able to mitigate CO poisoning and water management problems. Although the HT‐PEMFC has many attractive features, it also possesses many limitations and presents several challenges to its widespread commercialization. In this re‐view, the trends of HT‐PEMFC research and development with respect to electrochemistry, mem‐brane, modeling, fuel options, and system design were presented.

  2. 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)

  3. Design and performance analysis of micro proton exchange membrane fuel cells%微型质子交换膜燃料电池设计与性能分析

    Institute of Scientific and Technical Information of China (English)

    钟振忠; 陈俊勋; 彭荣贵

    2009-01-01

    This study describes a novel micro proton exchange membrane fuel cell (PEMFC)(active area ,2.5cm2)The flow field plate is manufactured by applying micro-electromechanica systems(MEMS) technology to silicon substrates to etch flow channels without a gold-coating.Therefore,this investigation uesd MEMS technology for fabrication of a flow field plate and presents a novel fabrication procedure.Various operating parameters,such as fuel temperature and fuel stoichinmetric flow rate, are tested to optimixe micro PEMFC performance.A single micro PEMFC using MEMS technology reveals the ideal performance of the proposed fuel cell.The optimal power density approaches 232.75mW·cm-1 when the fuel cell is operated atambient condition with humidified, heated fuel.

  4. 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.

  5. Enhancement of fuel cell performance with less-water dependent composite membranes having polyoxometalate anchored nanofibrous interlayer

    Science.gov (United States)

    Abouzari-lotf, Ebrahim; Jacob, Mohan V.; Ghassemi, Hossein; Ahmad, Arshad; Nasef, Mohamed Mahmoud; Zakeri, Masoumeh; Mehdipour-Ataei, Shahram

    2016-09-01

    Polyoxometalate immobilized nanofiber was used to fabricate low gas permeable layer for composite membranes designed for proton exchange membrane fuel cell (PEMFC) operating at low relative humidity (RH). The composite membranes revealed enhanced proton conductivity in dry conditions compared with state-of-the-art pristine membrane (Nafion 112, N112). This was coupled with a low fuel crossover inheriting the composite membranes about 100 mV higher OCV than N112 when tested in PEMFC at 60 °C and 40% RH. A maximum power density of up to 930 mW cm-2 was also achieved which is substantially higher than the N112 under similar conditions (577 mW cm-2). Such remarkable performance enhancement along with undetectable leaching of immobilized polyoxometalate, high dimensional stability and low water uptake of the composite membranes suggest a strong potential for PEMFC under low RH operation.

  6. 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.

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

    Directory of Open Access Journals (Sweden)

    Tian-Syung Lan

    2014-01-01

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

  8. 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

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

    Science.gov (United States)

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

    2016-11-01

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

  10. 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

  11. Effect of nitrogen crossover on purging strategy in PEM fuel cell systems

    DEFF Research Database (Denmark)

    Rabbani, Raja Abid; Rokni, Masoud

    2013-01-01

    A comprehensive study on nitrogen crossover in polymer electrolyte membrane fuel cell (PEMFC) system with anode recirculation is conducted and associated purging strategies are discussed. Such systems when employed in automobiles are subjected to continuous changes in load and external operating ...

  12. 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 (ME...

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

    DEFF Research Database (Denmark)

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

    2015-01-01

    We present up-to-date benchmarking methods for testing electrocatalysts for polymer exchange membrane fuel cells (PEMFC), using the rotating disk electrode (RDE) method. We focus on the oxygen reduction reaction (ORR) and the hydrogen oxidation reaction (HOR) in the presence of CO. We have chosen...

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

    DEFF Research Database (Denmark)

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

    2014-01-01

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

  15. 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

  16. 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...

  17. 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.

  18. 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...

  19. Proton exchange membrane fuel cell model for aging predictions: Simulated equivalent active surface area loss and comparisons with durability tests

    Science.gov (United States)

    Robin, C.; Gérard, M.; Quinaud, M.; d'Arbigny, J.; Bultel, Y.

    2016-09-01

    The prediction of Proton Exchange Membrane Fuel Cell (PEMFC) lifetime is one of the major challenges to optimize both material properties and dynamic control of the fuel cell system. In this study, by a multiscale modeling approach, a mechanistic catalyst dissolution model is coupled to a dynamic PEMFC cell model to predict the performance loss of the PEMFC. Results are compared to two 2000-h experimental aging tests. More precisely, an original approach is introduced to estimate the loss of an equivalent active surface area during an aging test. Indeed, when the computed Electrochemical Catalyst Surface Area profile is fitted on the experimental measures from Cyclic Voltammetry, the computed performance loss of the PEMFC is underestimated. To be able to predict the performance loss measured by polarization curves during the aging test, an equivalent active surface area is obtained by a model inversion. This methodology enables to successfully find back the experimental cell voltage decay during time. The model parameters are fitted from the polarization curves so that they include the global degradation. Moreover, the model captures the aging heterogeneities along the surface of the cell observed experimentally. Finally, a second 2000-h durability test in dynamic operating conditions validates the approach.

  20. 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.

  1. 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.

  2. 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.

  3. 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.

  4. 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

  5. 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

  6. 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

  7. 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.

  8. 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

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

    DEFF Research Database (Denmark)

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

    2012-01-01

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

  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. 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.)

  12. 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...

  13. 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.

  14. 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...

  15. 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.

  16. 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

  17. 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.

  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

    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...

  19. 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...

  20. 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

  1. 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...

  2. 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.

  3. 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

  4. 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...

  5. 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...

  6. Habilidades do desenvolvimento de prematuros Development abilities in preterm

    OpenAIRE

    Dionísia Aparecida Cusin Lamônica; Mirela Machado Picolini

    2009-01-01

    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 ...

  7. 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...

  8. 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...

  9. 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...

  10. 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, ...

  11. 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.

  12. 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 m...

  13. 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)

  14. Nonlinear predictive control for durability enhancement and efficiency improvement in a fuel cell power system

    Science.gov (United States)

    Luna, Julio; Jemei, Samir; Yousfi-Steiner, Nadia; Husar, Attila; Serra, Maria; Hissel, Daniel

    2016-10-01

    In this work, a nonlinear model predictive control (NMPC) strategy is proposed to improve the efficiency and enhance the durability of a proton exchange membrane fuel cell (PEMFC) power system. The PEMFC controller is based on a distributed parameters model that describes the nonlinear dynamics of the system, considering spatial variations along the gas channels. Parasitic power from different system auxiliaries is considered, including the main parasitic losses which are those of the compressor. A nonlinear observer is implemented, based on the discretised model of the PEMFC, to estimate the internal states. This information is included in the cost function of the controller to enhance the durability of the system by means of avoiding local starvation and inappropriate water vapour concentrations. Simulation results are presented to show the performance of the proposed controller over a given case study in an automotive application (New European Driving Cycle). With the aim of representing the most relevant phenomena that affects the PEMFC voltage, the simulation model includes a two-phase water model and the effects of liquid water on the catalyst active area. The control model is a simplified version that does not consider two-phase water dynamics.

  15. Estado Nacional e desenvolvimento: construindo um sistema financeiro a serviço do projeto de desenvolvimento nacional

    Directory of Open Access Journals (Sweden)

    Matheus Felipe de Castro

    2009-09-01

    Full Text Available O presente artigo avalia a capacidade financeira do Estado brasileiro, como nação dependente e subdesenvolvida e propõe medidas de política econômica destinadas a subordinar os sistemas tributário e financeiro à realização de um projeto político de desenvolvimento nacional, fundado no pleno emprego e na justiça social, cujas linhas gerais estão traçadas na própria Constituição da República Federativa do Brasil, de 1988.

  16. 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...

  17. 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.

  18. 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.

  19. 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.

  20. 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)

  1. 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.

  2. 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.

  3. A comprehensive review of PBI-based high temperature PEM fuel cells

    DEFF Research Database (Denmark)

    Simon Araya, Samuel; Zhou, Fan; Liso, Vincenzo;

    2016-01-01

    The current status on the understanding of the various operational aspects of high temperature proton exchange membrane fuel cells (HT-PEMFC) has been summarized. The paper focuses on phosphoric acid-doped polybenzimidazole (PBI)-based HT-PEMFCs and an overview of the common practices...... are outlined. Catalyst degradation and electrolyte loss take place at higher rates in the beginning of life of the fuel cell. This is due to the smaller size of Pt particles and the presence of excess phosphoric acid in the beginning of life that favor the respective degradation. Therefore, the redistribution...... of phosphoric acid in the membrane and the electrodes is crucial for the proper activation of the fuel cell, and a startup procedure should take this into account in order to avoid beginning of life degradation. On-line monitoring of the fuel cell system's state of health using diagnostic tools can help detect...

  4. 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.

  5. 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)

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

    DEFF Research Database (Denmark)

    Tripkovic, Vladimir; Cerri, Isotta; Nagami, Tetsuo;

    2013-01-01

    We have analyzed the aptitude of several metal oxide supports (TiO2, SnO2, NbO2, ZrO2, SiO2, Ta2O5 and Nb2O5) to redisperse platinum under electrochemical conditions pertinent to the Proton Exchange Membrane Fuel Cell (PEMFC) cathode. The redispersion on oxide supports in air has been studied in ...

  7. 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...

  8. 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...

  9. 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.

  10. Desenvolvimento neuropsicomotor de lactentes desnutridos Neuropsychomotor development of malnourished babies

    Directory of Open Access Journals (Sweden)

    SS Mansur

    2006-01-01

    Full Text Available OBJETIVOS: O objetivo deste estudo foi analisar o desenvolvimento neuropsicomotor de lactentes com desnutrição leve e caracterizar seu perfil nutricional. MÉTODOS: A pesquisa foi do tipo transversal, numa população de 374 lactentes e amostra de 31 desnutridos leve, entre 7 e 24 meses de idade, matriculados em creches municipais. O estado nutricional foi identificado pelo critério de Gómez e caracterizado por um questionário. Para a avaliação neuropsicomotora utilizou-se a Escala de Desenvolvimento Psicomotor da Primeira Infância de Brunet e Lézine. RESULTADOS: Os principais resultados do questionário mostraram: infecções respiratórias (48,4%; diarréias (71,0%; pais em união estável (61,3%; pais com ensino fundamental incompleto (74,2% das mães, 83,8% dos pais; renda familiar de 1 a 3 salários-mínimos (80,6%; aleitamento materno satisfatório (67,7%; reação adversa a algum alimento (41,9%. Entre os dados neuropsicomotores, as médias das Idades de Desenvolvimento da Linguagem (14,45 meses e da Sociabilidade (14,74 meses foram as que obtiveram os valores mais abaixo da média da Idade Cronológica (16,41 meses. Todas as áreas avaliadas obtiveram Quocientes de Desenvolvimento dentro da normalidade, porém, as áreas da Linguagem e da Sociabilidade foram classificadas em nível "normal baixo" e as outras em nível "normal médio". CONCLUSÕES: A avaliação neuropsicomotora é instrumento fundamental na assistência ao lactente desnutrido, que tende a apresentar deficiências nas áreas da Linguagem e Sociabilidade, fornecendo subsídios para observar sua atuação exploratória, efeito de seu pensamento, e planejar o trabalho intervencionista.OBJECTIVE: The purpose of this study was to analyze the neuropsychomotor development of babies with slight malnutrition and to characterize their nutritional profile. METHOD: This was a cross-sectional survey on a population of 374 babies and a sample of 31 babies with slight

  11. 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 ...

  12. 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...

  13. 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...

  14. 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...

  15. 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...

  16. Impedance Diagrams of the Electrodes in the Polymer Electrolyte Membrane Fuel Cell

    OpenAIRE

    Meland, Anne-Kristine

    2007-01-01

    The objective of this thesis was to better understand the electrodes of the polymer electrolyte membrane fuel cell (PEMFC), and especially the anode. We were interested in how CO poisoning affected the fuel cell and therefore we started by looking at the unpoisoned anode. It was important to get a good understanding of the mechanisms of the unpoisoned electrode to have a good background to understand the poisoned one.The electrodes were investigated using in situ electrochemical impedance spe...

  17. 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...

  18. 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.

  19. 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

  20. 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.

  1. 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.

  2. Proton Exchange Membranes for Fuel Cells Challenges and Recent Developments

    Institute of Scientific and Technical Information of China (English)

    Qingfeng Li; Jens Oluf Jensen; Pernille P. Noyé; Chao Pan; Niels J. Bjerrum

    2005-01-01

    @@ 1Introduction The current technology of proton exchange membrane fuel cells (PEMFC) is based on perfluorosulfonic acid (PFSA) membranes (e. g. Nafion(R)) as electrolyte. It operates on pure hydrogen and oxygen/air at typically 80℃ with high power density and long-term durability. For the membranes to be conductive, a minimum threshold of absorbed water molecules is about 6 to 7 mole per sulfonic site. The highest conductivity is only obtained under fully hydrated conductions, i.e. 21 - 22 mole water per sulfonic acid site. In other words, the proton conductivity is achieved by the locally liquid-like hydrophilic domain of the nanostructure.This strong dependence of conductivity on the water content in membranes limits the operational temperatureof PEMFC below 100℃.

  3. 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)

  4. High power fuel cell simulator based on artificial neural network

    Energy Technology Data Exchange (ETDEWEB)

    Chavez-Ramirez, Abraham U.; Munoz-Guerrero, Roberto [Departamento de Ingenieria Electrica, CINVESTAV-IPN. Av. Instituto Politecnico Nacional No. 2508, D.F. CP 07360 (Mexico); Duron-Torres, S.M. [Unidad Academica de Ciencias Quimicas, Universidad Autonoma de Zacatecas, Campus Siglo XXI, Edif. 6 (Mexico); Ferraro, M.; Brunaccini, G.; Sergi, F.; Antonucci, V. [CNR-ITAE, Via Salita S. Lucia sopra Contesse 5-98126 Messina (Italy); Arriaga, L.G. [Centro de Investigacion y Desarrollo Tecnologico en Electroquimica S.C., Parque Tecnologico Queretaro, Sanfandila, Pedro Escobedo, Queretaro (Mexico)

    2010-11-15

    Artificial Neural Network (ANN) has become a powerful modeling tool for predicting the performance of complex systems with no well-known variable relationships due to the inherent properties. A commercial Polymeric Electrolyte Membrane fuel cell (PEMFC) stack (5 kW) was modeled successfully using this tool, increasing the number of test into the 7 inputs - 2 outputs-dimensional spaces in the shortest time, acquiring only a small amount of experimental data. Some parameters could not be measured easily on the real system in experimental tests; however, by receiving the data from PEMFC, the ANN could be trained to learn the internal relationships that govern this system, and predict its behavior without any physical equations. Confident accuracy was achieved in this work making possible to import this tool to complex systems and applications. (author)

  5. Spectrophotometric Analysis of Phosphoric Acid Leakage in High-Temperature Phosphoric Acid-Doped Polybenzimidazole Membrane Fuel Cell Application

    Directory of Open Access Journals (Sweden)

    Seungyoon Han

    2016-01-01

    Full Text Available High-temperature proton exchange membrane fuel cells (HT-PEMFCs utilize a phosphoric acid- (PA- doped polybenzimidazole (PBI membrane as a polymer electrolyte. The PA concentration in the membrane can affect fuel cell performance, as a significant amount of PA can leak from the membrane electrode assembly (MEA by dissolution in discharged water, which is a byproduct of cell operation. Spectrophotometric analysis of PA leakage in PA-doped polybenzimidazole membrane fuel cells is described here. This spectrophotometric analysis is based on measurement of absorption of an ion pair formed by phosphomolybdic anions and the cationoid color reagent. Different color reagents were tested based on PA detection sensitivity, stability of the formed color, and accuracy with respect to the amount of PA measured. This method allows for nondestructive analysis and monitoring of PA leakage during HT-PEMFCs operation.

  6. 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.

  7. 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...

  8. Studies on PEM Fuel Cell Noble Metal Catalyst Dissolution

    DEFF Research Database (Denmark)

    Ma, Shuang; Skou, Eivind Morten

    Incredibly vast advance has been achieved in fuel cell technology regarding to catalyst efficiency, improvement of electrolyte conductivity and optimization of cell system. With breathtakingly accelerating progress, Proton Exchange Membrane Fuel Cells (PEMFC) is the most promising and most widely....... Membrane Electrode Assembly (MEA) is commonly considered as the heart of cell system [2]. Degradation of the noble metal catalysts in MEAs especially Three-Phase-Boundary (TPB) is a key factor directly influencing fuel cell durability. In this work, electrochemical degradation of Pt and Pt/Ru alloy were...

  9. 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.

  10. 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.

  11. 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

  12. 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

  13. 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...

  14. 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...... 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....

  15. Gas phase recovery of hydrogen sulfide contaminated polymer electrolyte membrane fuel cells

    Science.gov (United States)

    Kakati, Biraj Kumar; Kucernak, Anthony R. J.

    2014-04-01

    The effect of hydrogen sulfide (H2S) on the anode of a polymer electrolyte membrane fuel cell (PEMFC) and the gas phase recovery of the contaminated PEMFC using ozone (O3) were studied. Experiments were performed on fuel cell electrodes both in an aqueous electrolyte and within an operating fuel cell. The ex-situ analyses of a fresh electrode; a H2S contaminated electrode (23 μmolH2S cm-2); and the contaminated electrode cleaned with O3 shows that all sulfide can be removed within 900 s at room temperature. Online gas analysis of the recovery process confirms the recovery time required as around 720 s. Similarly, performance studies of an H2S contaminated PEMFC shows that complete rejuvenation occurs following 600-900 s O3 treatment at room temperature. The cleaning process involves both electrochemical oxidation (facilitated by the high equilibrium potential of the O3 reduction process) and direct chemical oxidation of the contaminant. The O3 cleaning process is more efficient than the external polarization of the single cell at 1.6 V. Application of O3 at room temperature limits the amount of carbon corrosion. Room temperature O3 treatment of poisoned fuel cell stacks may offer an efficient and quick remediation method to recover otherwise inoperable systems.

  16. 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...

  17. 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.

  18. 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.

  19. 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.

  20. High surface area graphite as alternative support for proton exchange membrane fuel cell catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Ferreira-Aparicio, P.; Folgado, M.A. [Centro de Investigaciones Energeticas, Medioambientales y Tecnologicas (CIEMAT), Avda. Complutense 22, E-28040 Madrid (Spain); Daza, L. [Centro de Investigaciones Energeticas, Medioambientales y Tecnologicas (CIEMAT), Avda. Complutense 22, E-28040 Madrid (Spain); Instituto de Catalisis y Petroleoquimica (CSIC), C/Marie Curie, 2 Campus de Cantoblanco, E-28049 Madrid (Spain)

    2009-07-01

    The suitability of a high surface area graphite (HSAG) as proton exchange membrane fuel cell (PEMFC) catalyst support has been evaluated and compared with that of the most popular carbon black: the Vulcan XC72. It has been observed that Pt is arranged on the graphite surface resulting in different structures which depend on the catalysts synthesis conditions. The influence that the metal particle size and the metal-support interaction exert on the catalysts degradation rate is analyzed. Temperature programmed oxidation (TPO) under oxygen containing streams has been shown to be a useful method to assess the resistance of PEMFC catalysts to carbon corrosion. The synthesized Pt/HSAG catalysts have been evaluated in single cell tests in the cathode catalytic layer. The obtained results show that HSAG can be a promising alternative to the traditionally used Vulcan XC72 carbon black when suitable catalysts synthesis conditions are used. (author)

  1. 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

  2. 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)

  3. 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.

  4. A Study of the Influence of Gas Channel Parameters on HT-PEM Fuel Cell Performance Using FEM Analysis

    Directory of Open Access Journals (Sweden)

    Ionescu Viorel

    2016-01-01

    Full Text Available Proton Exchange Membrane Fuel Cells (PEMFC are highly efficient power generators, achieving up to 50–60% conversion efficiency, even in sizes of a few kilowatts. Comsol Multiphysics, a commercial solver based on the Finite Element Method (FEM was used for developing a three dimensional model of a high temperature PEMFC that can deal with both anode and cathode flow field for examining the micro flow channel with electrochemical reaction. Cathode gas flow velocity influence on the cell performance was investigated at first. Polarization curves for three different channel widths (0.8, 1.6 and 2.4 mm and three different channel depths (1, 2 and 3 mm were computed at a cathode inlet flow velocity of 0.06 m/s. Oxygen molar concentration at cathode catalyst layer-GDL channel interface and local current density variation along the cell length were also studied for specific gas channel geometries.

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

    DEFF Research Database (Denmark)

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

    2010-01-01

    This paper presents test results regarding the poisoning effects of CO and CO2 on H3PO4/Polybenzimidazole (PBI) membrane based high temperature proton exchange membrane fuel cell (HT-PEMFC). Electrochemical impedance spectroscopy (EIS), which is a non intrusive diagnostic tool for electrochemical...... systems, has been used to investigate these effects. A single cell test setup consisting of an electrically heated single cell assembly with a PEMEAS CELTEC P membrane electrode assembly (MEA) of an active area of 45cm2 and mass flow controllers for Air, H2, CO and CO2 was constructed in the laboratory...... to the spectrum in order to analyze and quantify the impact of the individual factors on HT-PEMFC performance. Results showed that CO poisoning has an effect on all the losses monitored. Intermediate frequency resistances showed higher increase with increasing contamination and decreasing temperature than high...

  6. 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.

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

    Directory of Open Access Journals (Sweden)

    Óscar González-Espasandín

    2014-01-01

    Full Text Available The possibility of implementing fuel cell technology in Unmanned Aerial Vehicle (UAV propulsion systems is considered. Potential advantages of the Proton Exchange Membrane or Polymer Electrolyte Membrane (PEMFC and Direct Methanol Fuel Cells (DMFC, their fuels (hydrogen and methanol, and their storage systems are revised from technical and environmental standpoints. Some operating commercial applications are described. Main constraints for these kinds of fuel cells are analyzed in order to elucidate the viability of future developments. Since the low power density is the main problem of fuel cells, hybridization with electric batteries, necessary in most cases, is also explored.

  8. 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.

  9. 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...

  10. 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

  11. 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

  12. 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.

  13. 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...

  14. 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.

  15. 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...

  16. 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

  17. 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

    . It consists of a fuel cell stack, a fuel processing subsystem, heat exchangers, and balance-of-plant components. The optimization methodology involves system optimization attempting to maximize the net electrical efficiency, and then by use of a mixed integer nonlinear programming (MINLP) problem formulation......, the heat exchange network (HEN) annual cost is minimized. The results show the high potential of the proposed model since high efficiencies are accomplished. The net electrical efficiency and total system efficiency, based on lower heating value (LHV), are 35.2% and 91.1%, respectively. The minimized total...

  18. 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

  19. 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

  20. 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.

  1. Identification of critical parameters for PEMFC stack performance characterization and control strategies for reliable and comparable stack benchmarking

    DEFF Research Database (Denmark)

    Mitzel, Jens; Gülzow, Erich; Kabza, Alexander;

    2016-01-01

    This paper is focused on the identification of critical parameters and on the development of reliable methodologies to achieve comparable benchmark results. Possibilities for control sensor positioning and for parameter variation in sensitivity tests are discussed and recommended options for the ......This paper is focused on the identification of critical parameters and on the development of reliable methodologies to achieve comparable benchmark results. Possibilities for control sensor positioning and for parameter variation in sensitivity tests are discussed and recommended options...... for the control strategy are summarized. This ensures result comparability as well as stable test conditions. E.g., the stack temperature fluctuation is minimized to about 1 °C. The experiments demonstrate that reactants pressures differ up to 12 kPa if pressure control positions are varied, resulting...... in an average cell voltage deviation of 21 mV. Test parameters simulating different stack applications are summarized. The stack demonstrated comparable average cell voltage of 0.63 V for stationary and portable conditions. For automotive conditions, the voltage increased to 0.69 V, mainly caused by higher...

  2. 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.

  3. 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

  4. 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...

  5. 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.

  6. 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.

  7. 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

  8. 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...

  9. 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.

  10. 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.

  11. 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.

  12. 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...... are summarized as well. To date, lifetimes of this type of fuel cells of up to 18,000 h with degradation rates of around 5 μV/h at temperatures of 150–160 °C have been demonstrated using hydrogen and air under constant moderate load. However, the degradation rate increases by a factor 10 when the cell is exposed...

  13. Application of Proton Exchange Membrane Fuel Cell for Lift Trucks

    DEFF Research Database (Denmark)

    Hosseinzadeh, Elham; Rokni, Masoud

    2011-01-01

    in order to account for water back diffusion. Further Membrane water content is assumed to be a linear function of thickness. PEM fuel cell is working at rather low operating conditions which makes it suitable for the automotive systems. In this paper motive power part of a lift truck has been investigated......In this study a general PEMFC (Proton Exchange Membrane Fuel Cell) model has been developed to take into account the effect of pressure losses, water crossovers, humidity aspects and voltage over potentials in the cells. The model is zero dimensional and it is assumed to be steady state. The effect...

  14. 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...

  15. 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)

  16. Carbon film coating on gas diffusion layer for proton exchange membrane fuel cells

    Science.gov (United States)

    Lin, Jui-Hsiang; Chen, Wei-Hung; Su, Shih-Hsuan; Liao, Yuan-Kai; Ko, Tse-Hao

    This study discusses a novel process to increase the performance of proton exchange membrane fuel cells (PEMFC). In order to improve the electrical conductivity and reduce the surface indentation of the carbon fibers, we modified the carbon fibers with pitch-based carbon materials (mesophase pitch and coal tar pitch). Compared with the gas diffusion backing (GDB), GDB-A240 and GDB-MP have 32% and 33% higher current densities at 0.5 V, respectively. Self-made carbon paper with the addition of a micro-porous layer (MPL) (GDL-A240 and GDL-MP) show improved performance compared with GDB-A240 and GDB-MP. The current densities of GDL-A240 and GDL-MP at 0.5 V increased by 37% and 31% compared with GDL, respectively. This study combines these two effects (carbon film and MPL coating) to promote high current density in a PEMFC.

  17. Electrocatalysts and their Supporting Materials for Proton Exchange Membrane Fuel Cells: Activity and Durability Studies

    DEFF Research Database (Denmark)

    Permyakova, Anastasia Aleksandrovna

    This thesis describes investigations conducted exploring the activity, stability and durability of supported nano-particulate, bulk and thin film electrocatalysts used in proton exchange membrane fuel cells (PEMFCs). The effects of different factors and conditions on the reactions involved...... instruments: TEM (FEI Tecnai T20 G2), EDS, AFM, XRD (PANalytical Multipurpose Diffractometer) and FTIR-IR. Chapter 3 describes the results of synthesis and testing of the Pt nanoparticulate catalyst supported by PBI wrapped Graphene for oxygen reduction reaction in PEMFCs. The physiochemical material’s...... presented. Electrochemical characterisation showed a gradual improvement of activity for carbon monoxide and methanol electro-oxidation when higher Si contents were employed in the Pt-Si alloy. Chapter 5 describes the preparation, material characterisation and initial electrochemical measurements...

  18. 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.

  19. 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.

  20. Improvement of carbon corrosion resistance through heat-treatment in polymer electrolyte membrane fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Ko, Y.J.; Oh, H.S.; Kim, H. [Yonsei Univ., Seoul (Korea, Republic of). Dept. of Chemical and Biomolecular Engineering

    2010-07-01

    Electrochemical corrosion of carbon in the catalyst layer of polymer electrolyte membrane fuel cells (PEMFCs) is a critical factor in limiting their durability. The corrosion rate increases during the iterative abnormal operating conditions known as reverse current phenomenon. The corrosion causes a decrease of the active surface of the platinum (Pt) catalyst. The graphitization of carbon increases corrosion resistance, and the hydrophobicity of the carbon surface can also play an important role in decreasing carbon corrosion. This study investigated the effect of heat-treating carbon nanofibers (CNFs) for use in PEMFC applications. The aim of the study was to determine if heat treatments modified the carbon surface by eliminating the oxygen functional group and increasing hydrophobicity. The electrochemical carbon corrosion of CNFs were compared after heat treatments at various temperatures. Mass spectrometry was used to measure electrochemical carbon corrosion by monitoring the amounts of carbon dioxide (CO{sub 2}) produced during the electrochemical oxidation process. 2 refs.

  1. Desenvolvimento econômico, desigualdade e saúde Economic development, inequality, and health

    Directory of Open Access Journals (Sweden)

    Pedro Reginaldo Prata

    1994-09-01

    Full Text Available O autor se refere a dimensão socioeconômica, individual e coletiva do fenômeno saúde-doença. Refere-se também ao fato das populações estarem sobre a influência desigual de fatores de risco e de proteção à saúde. Discute as desigualdades no desenvolvimento e a relação entre desenvolvimento, riqueza, saúde e justiça social. Questiona as teorias de desenvolvimento econômico, diferenciando desenvolvimento de crescimento. Cunha os conceitos de armadilha do desenvolvimento e refugiados sociais. Define uma comunidade saudável. Propõe a necessidade de mudança no modelo de desenvolvimento. Baliza o papel e as limitações do setor saúde no que diz respeito a iniqüidade social.The author refers to the social, economic, individual, and collective dimensions of the relationship between health and disease. He considers that individuals and populations are not equally exposed to protective and risk factors. He highlights the uneven development between nations and Brazilian regions, and communities, as well as discussing the relationship between development, wealth, health, and social justice. The article analyzes development theories and makes a distinction between economic development and growth. The concepts of development trap and social refugees are coined. The author defines a healthy community, points to the need for a shift in the current development model, and delineates the health sector's role and limitations in dealing with social inequality.

  2. 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.

  3. 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

  4. POLÍTICAS PÚBLICAS E CAPITAL HUMANO PARA O DESENVOLVIMENTO LOCAL DA PESCA ARTESANAL

    OpenAIRE

    João Henrique de Melo Ferraz; Fellipe Neri de Oliveira Arrais

    2014-01-01

    Este trabalho identifica e analisa as políticas públicas de extensão pesqueira para o desenvolvimento local do Município de Porto de Pedras, Alagoas, entre 2003 e 2009, por meio dos projetos estabelecidos pelo governo. Especificamente, se analisa o capital humano da colônia de pescadores Z-25, frente aos projetos tecnológicos ligados à pesca artesanal. A metodologia utilizada neste trabalho foi a identificação das políticas públicas para o desenvolvimento da pesca artesanal, além de aplicação...

  5. 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...

  6. 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...

  7. 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...

  8. 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...

  9. 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...

  10. 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...

  11. 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...

  12. 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...

  13. 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...

  14. 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, ...

  15. 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...

  16. 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 ...

  17. 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

  18. Desenvolvimento limpo : uma nova cooperação entre Portugal e os PALOP

    OpenAIRE

    Gomes, Carla Maria

    2009-01-01

    Este trabalho propõe analisar as políticas de cooperação em Portugal e perceber de que modo a Convenção Internacional para as Alterações Climáticas, nomeadamente o Protocolo de Quioto, provocou uma mudança de prioridades e de estratégia. À luz de um novo paradigma da “cooperação para o desenvolvimento sustentável”, procura-se avaliar o potencial dos Países Africanos de Língua Oficial Portuguesa como parceiros em futuros projectos de Desenvolvimento Limpo, em particular de Fontes de Ener...

  19. 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...

  20. 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. 

  1. 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...

  2. 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)

  3. 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.

  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. Regulação do desenvolvimento de micorrizas arbusculares Regulation of arbuscular mycorrhizae development

    Directory of Open Access Journals (Sweden)

    Soraya Gabriela Kiriachek

    2009-02-01

    Full Text Available As micorrizas arbusculares (MAs são associações simbióticas mutualistas entre fungos do filo Glomeromycota e a maioria das plantas terrestres. A formação e o funcionamento das MAs depende de um complexo processo de troca de sinais, que resulta em mudanças no metabolismo dos simbiontes e na diferenciação de uma interface simbiótica no interior das células das raízes. Os mecanismos que regulam a formação das MAs são pouco conhecidos, mas sabe-se que a concentração de fosfato (P na planta é um fator determinante para o desenvolvimento da simbiose. A disponibilidade de P na planta pode afetar o balanço de açúcares e de fitormônios (FHs, além da expressão de genes de defesa vegetal. Com o advento da genômica e proteômica, vários genes essenciais para o desenvolvimento das MAs já foram identificados e seus mecanismos de regulação estão sendo estudados. Até o presente, sabe-se que as plantas secretam substâncias que estimulam a germinação de esporos e o crescimento de fungos micorrízicos arbusculares (FMAs. Há evidências também de que os FMAs sintetizam moléculas sinalizadoras, que são reconhecidas pelas plantas hospedeiras. Pelo menos três genes são essenciais para o reconhecimento dessa molécula e a transdução do sinal molecular. Discutem-se os papéis desses genes e os possíveis mecanismos que regulam sua expressão, bem como os papéis dos FHs na regulação de MAs são discutidos.Arbuscular mycorrhizae (AM are mutualistic symbiotic associations between fungi of the phylum Glomeromycota and most terrestrial plants. The formation and functioning of AM depend on a complex signal exchange process, which ultimately results in shifts in the metabolism of the symbionts and differentiation of a symbiotic interface in cortical root cells. The mechanisms regulating AM development are not well understood, but it is known that phosphate (P concentration in plants plays a key role in this process. Plant P

  8. 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

  9. 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 ...

  10. Biopolítica e Desenvolvimento? Foucault e Agamben sobre Estado, Governo e Violência

    Directory of Open Access Journals (Sweden)

    Guilherme F. W. Radomsky

    2015-06-01

    Full Text Available Este artigo analisa as relações entre biopolítica e desenvolvimento sob o ângulo das noções de Estado, governo e violência. O objetivo consiste em examinar elementos analíticos que gravitam em torno de perspectivas críticas do desenvolvimento buscando um eixo interpretativo sobre a ambivalência das ações do Estado a partir de duas possibilidades teóricas que convergem no pensamento de Giorgio Agamben: a análise do biopoder e do governo em Foucault e as articulações entre violência e lei que remetem a Walter Benjamin. A reflexão sobre os argumentos teóricos é realizada examinando-se dados oriundos de pesquisa de abordagem qualitativa sobre políticas para a agricultura ecológica no sul do Brasil. As conclusões mostram que o desenvolvimento e seus benefícios podem ser problematizados pelo olhar do biopoder e da violência, que reconfiguram o que seja desenvolvimento, menos como expansão do bem-estar e mais como impulso modernizante de mudança que se ampara em administrar a vida.

  11. A aplicação do QFD no desenvolvimento de software: um estudo de caso

    Directory of Open Access Journals (Sweden)

    Fernando Antônio Sonda

    2000-06-01

    Full Text Available Este trabalho tem como objetivo apresentar a aplicação do QFD como ferramenta de suporte para o planejamento e desenvolvimento de um software de custos, visando um melhor atendimento das características demandadas pelo cliente, bem como a determinação de indicadores para controlar o processo de desenvolvimento do produto. O trabalho foi desenvolvido a partir de uma pesquisa de mercado realizada com usuários de softwares de custos e demais pessoas envolvidas com o gerenciamento de custos. Com a aplicação do QFD, observou-se que a definição antecipada das características principais do sistema é fundamental para o desenvolvimento de um software. O QFD vem se somar as demais ferramentas de análise de sistemas proporcionando, simultaneamente, um desenvolvimento mais rápido e mais qualificado.This paper presents an application of QFD for planning and development of a cost software. The QFD was chosen aiming a better assessment of the user desires as well as the indication of the parameters for process control. The work was initiated from a market survey conducted on users of cost software and other people involved in cost management. The use of the QFD shows that the early definition of the key characteristics of the system is essential in software development. The QFD complements the use of other system analysis techniques and contributes for a faster and more qualified software development.

  12. 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.

  13. 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.

  14. 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.

  15. 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.

  16. 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...... composition. The degradation of the platinum catalyst and polymer was analyzed in relation to the preparation conditions. An optimal electrode interface structure can improve Pt performance by (1) providing high platinum utilization; (2) decreasing platinum migration and coalescence; (3) reducing carbon...

  17. 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...... diffusion layer, microporous layer, and catalyst layer, excluding the membrane and anode. In the porous media liquid water transport is described by the capillary pressure gradient, momentum loss via the Darcy-Forchheimer equation, and mass transfer between phases by a nonequilibrium phase change model....... Furthermore, the presence of irreducible liquid water is taken into account. In order to account for compression, porous media morphology variations are specified based on the gas diffusion layer (GDL) through-plane strain and intrusion which are stated as a function of compression. These morphology...

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

    DEFF Research Database (Denmark)

    Li, Qingfeng

    2003-01-01

    The technical achievement and challenges for the PEMFC technology based on perfluorosulfonic acid (PFSA) polymer membranes (e.g. Nafion®) are briefly discussed. The newest development for alternative polymer electrolytes for operation above 100°C. As one of the successful approaches to high opera...... operational temperatures, the development and evaluation of acid doped PBI membranes are reviewed, covering polymer synthesis, membrane casting, acid doping, physiochemical characterization and fuel cell tests.......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...

  19. 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

  20. The direct borohydride fuel cell for UUV propulsion power

    Science.gov (United States)

    Lakeman, J. Barry; Rose, Abigail; Pointon, Kevin D.; Browning, Darren J.; Lovell, Keith V.; Waring, Susan C.; Horsfall, Jackie A.

    The development of proton exchange membrane and direct methanol fuel cell stacks is now well advanced for many applications. However, the significant performance advantages that these have over the battery for small to moderate scale applications will not be realised until a credible fuel source has been developed. The deficiencies of the PEMFC and DMFC can be eliminated by cation or anion-conducting membranes incorporated into a direct sodium borohydride fuel cell (DSBFC). The characterisation of membranes for the DSBFC is discussed. Novel membranes have been prepared which have resistance of an equal magnitude to the commercially available Nafion ® membrane.

  1. 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.

  2. Analysis on Assembly of 3-stage Galvanic Pile of PEMFC Fuel Cell%PEMFC燃料电池三级电堆的装配分析

    Institute of Scientific and Technical Information of China (English)

    汪洋锋; 陈涛; 艾有俊; 杜斌

    2015-01-01

    以提高PEMFC燃料电池电堆性能为目的,研究了电堆组装过程中加载方式和载荷对电堆接触电阻及电堆性能的影响.利用有限元分析软件ANSYS Workbench对三级电堆的装配过程进行有限元分析.分析了几种不同大小的载荷及不同的加载方式的装配对电堆性能的影响,对比了这几种情况下燃料电池堆的核心部件膜电极(MEA)组件的变形情况及应力分布情况,得出电堆的最佳装配载荷.该结果可为燃料电池电堆的装配提供较好的参考依据.

  3. Desenvolvimento de recursos didácticos informatizados no âmbito da educação para o desenvolvimento sustentável. o exemplo do courseware SeRe

    OpenAIRE

    Sá, P; Guerra, C.; Isabel P. Martins; Loureiro, M. J.; Vieira, R.; Costa, A. P.; Reis, L. P.

    2010-01-01

    A falta de recursos didácticos informatizados de qualidade para o 1º e 2º Ciclos do Ensino Básico (1º/2º CEB), concebidos no âmbito da Educação para o Desenvolvimento Sustentável (EDS), numa perspectiva de Ensino por Pesquisa, determinou a organização de uma equipa multidisciplinar para o desenvolvimento do «Courseware Sere - O Ser Humano e os Recursos Naturais». Ajustando alguns princípios de desenvolvimento de software, particularmente de Design Centrado no Utilizador (DCU), o trabalho da e...

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

    OpenAIRE

    Yoshiyuki Show; Toshimitsu Nakashima; Yuta Fukami

    2013-01-01

    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 assemb...

  5. 车用燃料电池技术的现状与研究热点%Current Status and Perspective of Vehicular Fuel Cell Technologies

    Institute of Scientific and Technical Information of China (English)

    侯明; 俞红梅; 衣宝廉

    2009-01-01

    As a kind of clean energy vehicles, fuel cell automobiles have been developed in the past decade. Although tremendous progress has been made, the durability and the cost of the fuel cells are the bottlenecks of the fuel cell vehicles' commercialization. Materials for proton exchange membrane fuel cells (PEMFCs) are the key issues. The overview of the key materials of PEMFCs, I.e., electrocatalyst, proton exchange membrane and bipolar plate, is given. The hot research topics are analyzed. The key issues of PEMFCs for automobile operation are electrocatalyst degradation, membrane degradation and bipolar plate corrosion, etc. Possible solutions and perspectives of PEMFCs are summarized.%燃料电池汽车作为清洁能源汽车近十几年来得到很大的发展.然而燃料电池的寿命、成本仍然是制约其商业化的瓶颈,其中材料是根本问题.本文对组成燃料电池的三种关键材料即电催化剂、质子交换膜、双极板的发展现状进行了综述,并对研究热点进行了剖析.针对燃料电池在车载工况下的问题,如电催化剂衰减、膜降解、双极板腐蚀等,基于已有试验结果和理论分析指出了可能的解决方案、对策与发展方向.

  6. Enhanced stability of multilayer graphene-supported catalysts for polymer electrolyte membrane fuel cell cathodes

    Science.gov (United States)

    Marinkas, A.; Hempelmann, R.; Heinzel, A.; Peinecke, V.; Radev, I.; Natter, H.

    2015-11-01

    One of the biggest challenges in the field of polymer electrolyte membrane fuel cells (PEMFC) is to enhance the lifetime and the long-term stability of PEMFC electrodes, especially of cathodes, furthermore, to reduce their platinum loading, which could lead to a cost reduction for efficient PEMFCs. These demands could be achieved with a new catalyst support architecture consisting of a composite of carbon structures with significant different morphologies. A highly porous cathode catalyst support layer is prepared by addition of various carbon types (carbon black particles, multi-walled carbon nanotubes (MWCNT)) to multilayer graphene (MLG). The reported optimized cathodes shows extremely high durability and similar performance to commercial standard cathodes but with 89% lower Pt loading. The accelerated aging protocol (AAP) on the membrane electrode assemblies (MEA) shows that the presence of MLG increases drastically the durability and the Pt-extended electrochemical surface area (ECSA). In fact, after the AAP slightly enhanced performance can be observed for the MLG-containing cathodes instead of a performance loss, which is typical for the commercial carbon-based cathodes. Furthermore, the presence of MLG drastically decreases the ECSA loss rate. The MLG-containing cathodes show up to 6.8 times higher mass-normalized Pt-extended ECSA compared to the commercial standard systems.

  7. A new model for thermal contact resistance between fuel cell gas diffusion layers and bipolar plates

    Science.gov (United States)

    Sadeghifar, Hamidreza; Djilali, Ned; Bahrami, Majid

    2014-11-01

    A new analytical model is developed to predict the thermal contact resistance (TCR) between fibrous porous media such as gas diffusion layers (GDLs) of polymer electrolyte membrane fuel cells (PEMFCs) and flat surfaces (bipolar plates). This robust model accounts for the salient geometrical parameters of GDLs, mechanical deformation, and thermophysical properties of the contacting bodies. The model is successfully validated against experimental data, and is used to perform in a comprehensive parametric study to investigate the effects of fiber parameters such as waviness and GDL properties on the TCR. Fiber waviness, diameter and surface curvature, as well as GDL porosity, are found to have a strong influence on TCR whereas fiber length does not affect the TCR when the porosity is kept constant. Such findings provide useful guidance for design and manufacturing of more effective GDLs for PEMFC heat management. The analytic model can be readily implemented in simulation and modeling of PEMFCs, and can be extended with minor modifications to other fibrous porous media such as fibrous catalysts, insulating media and sintered metals.

  8. Electrochemical stability of carbon nanofibers in proton exchange membrane fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Alvarez, Garbine [Energy Department, CIDETEC-IK4, Po Miramon, 196, 20009 San Sebastian (Spain); Alcaide, Francisco, E-mail: falcaide@cidetec.es [Energy Department, CIDETEC-IK4, Po Miramon, 196, 20009 San Sebastian (Spain); Miguel, Oscar [Energy Department, CIDETEC-IK4, Po Miramon, 196, 20009 San Sebastian (Spain); Cabot, Pere L. [Laboratori d' Electroquimica de Materials i del Medi Ambient, Dept. Quimica Fisica, Universitat de Barcelona, Marti i Franques, 1-11, 08028 Barcelona (Spain); Martinez-Huerta, M.V.; Fierro, J.L.G. [Instituto de Catalisis y Petroleoquimica (CSIC), Marie Curie 2, Cantoblanco, 28049 Madrid (Spain)

    2011-10-30

    This fundamental study deals with the electrochemical stability of several non-conventional carbon based catalyst supports, intended for low temperature proton exchange membrane fuel cell (PEMFC) cathodes. Electrochemical surface oxidation of raw and functionalized carbon nanofibers, and carbon black for comparison, was studied following a potential step treatment at 25.0 deg. C in acid electrolyte, which mimics the operating conditions of low temperature PEMFCs. Surface oxidation was characterized using cyclic voltammetry, X-ray photoelectron spectroscopy (XPS), and contact angle measurements. Cyclic voltammograms clearly showed the presence of the hydroquinone/quinone couple. Furthermore, identification of carbonyl, ether, hydroxyl and carboxyl surface functional groups were made by deconvolution of the XPS spectra. The relative increase in surface oxides on carbon nanofibers during the electrochemical oxidation treatment is significantly smaller than that on carbon black. This suggests that carbon nanofibers are more resistant to the electrochemical corrosion than carbon black under the experimental conditions used in this work. This behaviour could be attributed to the differences found in the microstructure of both kinds of carbons. According to these results, carbon nanofibers possess a high potential as catalyst support to increase the durability of catalysts used in low temperature PEMFC applications.

  9. Hydrogen from methanol for fuel cells in mobile systems: development of a compact reformer

    Science.gov (United States)

    Höhlein, B.; Boe, M.; Bøgild-Hansen, J.; Bröckerhoff, P.; Colsman, G.; Emonts, B.; Menzer, R.; Riedel, E.

    On-board generation of hydrogen from methanol with a reformer in connection with the use of a proton-exchange membrane fuel cell (PEMFC) is an attractive option for a passenger car drive. Special considerations are required to obtain low weight and volume. Furthermore, the PEMFC of today cannot tolerate more than 10 ppm of carbon monoxide in the fuel. Therefore a gas conditioning step is needed after the methanol reformer. Our main research activities focus on the conceptual design of a drive system for a passenger car with methanol reformer and PEMFC: engineering studies with regard to different aspects of this design including reformer, catalytic burner, gas conditioning, balances of the fuel cycles and basic design of a compact methanol reformer. The work described here was carried out within the framework of a JOULE II project of the European Union (1993-1995). Extensive experimental studies have been carried out at the Forschungszentrum Jülich GmbH (KFA) in Germany and at Haldor Topsøe A/S in Denmark.

  10. Probabilistic multiobjective operation management of MicroGrids with hydrogen storage and polymer exchange fuel cell power plants

    Energy Technology Data Exchange (ETDEWEB)

    Niknam, T.; Golestaneh, F. [Department of Electrical and Electronics Engineering, Shiraz University of Technology, Shiraz (Iran, Islamic Republic of)

    2012-10-15

    This paper models and solves the operation management problem of MicroGrids (MGs) including cost and emissions minimization under uncertain environment. The proposed model emphasizes on fuel cells (FCs) as a prime mover of combined heat and power (CHP) systems. An electro-chemical model of the proton exchange membrane fuel cell (PEMFC) is used and linked to the daily operating cost and emissions of the MGs. A reformer is considered to produce hydrogen for PEMFCs. Moreover, in high thermal load intervals, in order to make the MG more efficient, a part of produced hydrogen is stored in a hydrogen tank. The stored hydrogen can be reused by PEMFCs to generate electricity or be sold to other hydrogen consumers. A probabilistic optimization algorithm is devised which consists of 2m + 1 point estimate method to handle the uncertainty in input random variables (IRVs) and a multi-objective Self-adaptive Bee Swarm Optimization (SBSO) algorithm to minimize the cost and emissions simultaneously. Several techniques are proposed in the SBSO algorithm to make it a powerful black-box optimization tool. The efficiency of the proposed approach is verified on a typical grid-connected MG with several distributed energy sources. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  11. Optimization of electrical conduction and passivity properties of stainless steels used for PEM fuel cell bipolar plates

    International Nuclear Information System (INIS)

    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)

  12. A Transient Model for Fuel Cell Cathode-Water Propagation Behavior inside a Cathode after a Step Potential

    Directory of Open Access Journals (Sweden)

    Der-Sheng Chan

    2010-04-01

    Full Text Available Most of the voltage losses of proton exchange membrane fuel cells (PEMFC are due to the sluggish kinetics of oxygen reduction on the cathode and the low oxygen diffusion rate inside the flooded cathode. To simulate the transient flooding in the cathode of a PEMFC, a transient model was developed. This model includes the material conservation of oxygen, vapor, water inside the gas diffusion layer (GDL and micro-porous layer (MPL, and the electrode kinetics in the cathode catalyst layer (CL. The variation of hydrophobicity of each layer generated a wicking effect that moves water from one layer to the other. Since the GDL, MPL, and CL are made of composite materials with different hydrophilic and hydrophobic properties, a linear function of saturation was used to calculate the wetting contact angle of these composite materials. The balance among capillary force, gas/liquid pressure, and velocity of water in each layer was considered. Therefore, the dynamic behavior of PEMFC, with saturation transportation taken into account, was obtained in this study. A step change of the cell voltage was used to illustrate the transient phenomena of output current, water movement, and diffusion of oxygen and water vapor across the entire cathode.

  13. Exegoeconomic Analysis On A Proton Electrolyte Membrane Fuel Cell

    International Nuclear Information System (INIS)

    The objective of this study is to perform an exergy and economic analysis on proton electrolyte membrane fuel cell power system (PEMFC) known as exegoeconomic. A 5 kW PEMFC was taken as case study. The fuel cell includes the hydrogen processing system and a fuel cell stack. The hydrogen processing system consisted of an auto-thermal reactor (ATR), a water gas shift reactor (WGS), tubular ceramic membrane module (TCR) and a pressure swing adsorber (PSA). The fuel cell stack was the main power generator. It was obseved that TCM and PSA have low energy efficiency of 0.29 % and 0.09 % respectively. Energy efficiency for the auto-thermal reactor and fuel cell stack were higher at 22.44 % and 31.97 % respectively and both values are comparable with other studies. The exergoeconomics for the 5kW fuel cell system was determined as RM4756.62 per GJ. From the analysis, it is also found that the fuel cell cost can more competitive, if the cost of operation, maintenance and fuel can be reduced. (author)

  14. O sector rural como componente fundamental no processo de desenvolvimento dos países do sul

    OpenAIRE

    Jordão, Maria Fernanda dos Santos

    2007-01-01

    Mestrado em Desenvolvimento e Cooperação Internacional Depois de algumas décadas em que o paradigma de desenvolvimento dominante assentou essencialmente no crescimento da indústria, muitos países em desenvolvimento, nomeadamente na África Subsariana, não conseguem sair da pobreza e desenvolver as suas economias. Esta concentração excessiva no crescimento da indústria fez-se muitas vezes com custos elevadíssimos para o sector agrícola e para as populações rurais dos países em desenvolviment...

  15. Concepções sobre desenvolvimento infantil na perspectiva de educadoras em creches públicas e particulares

    OpenAIRE

    dos Santos, Ellis Regina Ferreira; Ramos, Deborah Dornellas; Nádia Maria Ribeiro SALOMÃO

    2015-01-01

    Neste estudo, objetivou-se investigar as concepções de educadoras de creches públicas e particulares sobre desenvolvimento infantil. Desse modo, aplicou-se uma entrevista semiestruturada a 24 educadoras. Os dados foram analisados a partir da técnica de análise de conteúdo categorial temática. De modo geral, verificou-se que, em relação às concepções sobre desenvolvimento infantil, predominou, nos dois grupos de educadoras, a subcategoria Desenvolvimento por estágios. Essas educadoras destacar...

  16. Investigation of transport phenomena in a 7-serpentine channel PEM fuel cell

    International Nuclear Information System (INIS)

    Full text: In the past decade, numerical modeling and investigation of PEM fuel cells has received great attention. Many two- and three-dimensional models have been developed in which the computational fluid dynamics -CFD method - has been rigorously coupled with electrochemical phenomena in order to identify, understand, predict, control and optimize various transport and electro-chemical processes that occur at different length scales in the fuel cells. Tremendous progress, both engineering and scientific, made until now has helped to improve the electrochemical performance of PEM fuel cells. Nevertheless, there is an increasing consensus on the need to further improve the performance of PEM fuel cell through design optimization of fuel cell components. Mathematical modeling of PEM fuel cells, based on an accurate description of the mechanisms of various processes occurring within a fuel cell, is an indispensable tool for exploring various architectures for fuel cells and their components. Channel geometry (path length, size, shape) has a tremendous impact on PEMFC performance. Distributions of the reactant species concentration in a PEM fuel cell due to fuel consumption and local transport of water through the membrane can cause changes in current density, temperature and water concentration. Water distribution can lead to flooding or drying of the membrane that may shorten the PEMFC components life. Finding a flow field pattern that distribute the gas more evenly is one method in minimizing these problems and optimising the PEM fuel cell performance. The paper describes our approach in modeling the transport of relevant quantities (mass, chemical species, and charged species) in all components of a fuel cell. The PEM fuel cell simulated in this work consists of two flow-field patterns separated by gas diffusion layers (GDL) and a membrane electrode assembly (MEA). Serpentine flow fields are common, yet the underlying reason for their success has yet to be

  17. Effects of pore size gradient in the substrate of a gas diffusion layer on the performance of a proton exchange membrane fuel cell

    International Nuclear Information System (INIS)

    Highlights: • The dual layered substrate with different carbon fibers formed a pore size gradient. • The gradient increased the cell performances under various humidity conditions. • The water management was improved by balancing the capillary pressure gradient. - Abstract: The proton exchange membrane fuel cell (PEMFC) is one of the up-and-coming power sources for automotive vehicles. To generate a stable performance during driving, the PEMFC needs to achieve an optimized water management under various humidity conditions. Being the path for the two-phase flow of fuel, air, and water, the gas diffusion layer (GDL) is a critical component, which influences water balance. In this study, a pore size gradient structure is introduced in the substrate of a GDL to control the local capillary pressure gradient, which is the driving force of the water flux inside the PEMFC. Through measurements of steady-state performance, transient response, voltage instability and electrochemical impedance spectroscopy, it was found that the pore size gradient structure improves the cell performance regardless of the relative humidity conditions used (50% and 100%). Furthermore, it is possible to hold the water on the membrane for higher ion conductivity and drain it toward the channel to secure gas supply toward the catalyst layer. In addition, it was also confirmed that the structural change enhances the bending stiffness of the GDL

  18. Speeding the transition: Designing a fuel-cell hypercar

    Energy Technology Data Exchange (ETDEWEB)

    Williams, B.D.; Moore, T.C.; Lovins, A.B. [Rocky Mountain Inst., Snowmass, CO (United States). Hypercar Center

    1997-12-31

    A rapid transformation now underway in automotive technology could accelerate the transition to transportation powered by fuel cells. Ultralight, advanced-composite, low-drag, hybrid-electric hypercars--using combustion engines--could be three- to fourfold more efficient and one or two orders of magnitude cleaner than today`s cars, yet equally safe, sporty, desirable, and (probably) affordable. Further, important manufacturing advantages--including low tooling and equipment costs, greater mechanical simplicity, autobody parts consolidation, shorter product cycles, and reduced assembly effort and space--permit a free-market commercialization strategy. This paper discusses a conceptual hypercar powered by a proton-exchange-membrane fuel cell (PEMFC). It outlines the implications of platform physics and component selection for the vehicle`s mass budget and performance. The high fuel-to-traction conversion efficiency of the hypercar platform could help automakers overcome the Achilles` heel of hydrogen-powered vehicles: onboard storage. Moreover, because hypercars would require significantly less tractive power, and even less fuel-cell power, they could adopt fuel cells earlier, before fuel cells` specific cost, mass, and volume have fully matured. In the meantime, commercialization in buildings can help prepare fuel cells for hypercars. The promising performance of hydrogen-fueled PEMFC hypercars suggests important opportunities in infrastructure development for direct-hydrogen vehicles.

  19. Desenvolvimento de inibidores do fator VIII na hemofilia A Development of factor VIII inhibitors in hemophilia A

    Directory of Open Access Journals (Sweden)

    Daniel G. Chaves

    2009-01-01

    Full Text Available A hemofilia A é uma coagulopatia genética com herança recessiva ligada ao cromossomo X que afeta 1-2 a cada 10 mil indivíduos do sexo masculino nascidos vivos. Estes indivíduos têm baixas concentrações ou ausência do fator VIII (FVIII da coagulação no plasma e apresentam quadros hemorrágicos leves, moderados e graves, dependendo da atividade de FVIII circulante. Estes pacientes necessitam de constante reposição proteica e aproximadamente 30% deles desenvolvem aloanticorpos contra a proteína exógena. A síntese dos anticorpos anti-FVIII é iniciada quando o FVIII exógeno é endocitado por células apresentadoras de antígeno, degradado e apresentado às células T CD4+ na forma de peptídeos ligados a moléculas do complexo maior de histocompatibilidade (MHC de classe II. Alguns fatores de risco (paciente/tratamento podem ser relacionados ao desenvolvimento desta resposta imune. Neste contexto, as mutações no gene do FVIII e polimorfismos em genes envolvidos na resposta imune são candidatos moleculares como determinantes imunogenéticos na predisposição para o desenvolvimento de inibidores. Por não ser completamente entendido e controlado, o desenvolvimento desta resposta imune contra o FVIII constitui o maior problema decorrente do tratamento de indivíduos portadores de hemofilia A e faz-se necessária busca de opções que visem minimizar suas ações deletérias. Algumas alternativas de tratamento têm se mostrado eficazes no tratamento (anti-CD20, plasmaférese, concentrado de complexo protrombínico (PCCs, concentrado de complexo protrombínico ativado (APCCs, fator VII humano ativado, mas a retirada ou neutralização específica dos inibidores de FVIII ainda não foram alcançadas.Hemophilia A, which affects 1-2:10,000 live-born male neonates, is a genetic coagulopathy with recessive inheritance linked to the X chromosome. These individuals have low concentrations or no coagulation factor VIII (FVIII in the plasma

  20. Constant Power Control of a Proton Exchange Membrane Fuel Cell through Adaptive Fuzzy Sliding Mode

    Directory of Open Access Journals (Sweden)

    Minxiu Yan

    2013-05-01

    Full Text Available Fuel cell is a device that converts the chemical energy from a fuel into electricity through a chemical reaction with oxygen or another oxidizing agent. The paper describes a mathematical model of proton exchange membrane fuel cells by analyzing the working mechanism of the proton exchange membrane fuel cell. Furthermore, an adaptive fuzzy sliding mode controller is designed for the constant power output of PEMFC system. Simulation results prove that adaptive fuzzy sliding mode control has better control effect than conventional fuzzy sliding mode control.

  1. Synthesis of a new electrolyte by co-poly-esters doped with sodium dodecyl sulfate for application on PEM fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Fiuza, J.R.A.; Boaventura, F.J.S.; Jose, N.M.; Bresciani, D. [Univ. Federal da Bahia, Salvador (Brazil). Dept. of Physical Chemistry

    2009-07-01

    Proton exchange membrane fuel cells (PEMFCs) use polymer membranes as electrolytes and protons as conductors. This paper reported on a study in which co-polyesters were doped with sodium dodecyl sulfate. The co-polymers were synthesized by a copolymerization process that used terephthalic and adipic acids with glycerol. A reactor was used to process the material, which was then hot-pressed to produce homogenous and flexible plates. X-ray diffraction (XRD) scanning electron microscopy (SEM), thermogravimetric, direct scanning calorimetry (DSC) and Fourier Transform Infrared (FTIR) analyses were conducted. Results of the analyses demonstrated that the composite material was stable up to a temperature of 250 degrees C. A micrographics study showed that MDS was homogeneously dispersed in the polymeric matrix. It was concluded that with an electrical conductivity between 10-7 to 10-1 S per cm, the copolymers were suitable for use in PEMFC applications.

  2. Research of platinum catalysts used in PEM fuel cell%质子交换膜燃料电池含Pt催化剂的研究

    Institute of Scientific and Technical Information of China (English)

    雷一杰; 李彤; 顾军; 于涛; 邹志刚

    2011-01-01

    作为质子交换膜燃料电池的主要用催化剂,Pt的研究对质子交换膜燃料电池运用和普及起着至关重要的作用.为此,近年来一系列大量的基于Pt催化剂的不同形貌、不同成分、不同载体的研究大大地推进了Pt催化剂技术的发展.%As the main catalyst used in proton exchange membrane fuel cell(PEMFC), the platinum research plays a vital role on the application and popularization of PEMFC. In this respect, a great deal of effort has been put into the morphologies, ingredients, supporters based on the platinum catalysts in recent years, which has promoted the catalyst technology.

  3. Environmental analysis of the proton exchange membrane fuel cell on the subject of life cycle assessment

    International Nuclear Information System (INIS)

    The energy is the fuel of growth and an essential requirement for the socioeconomic development. However, the current production model is based on fossil fuels, considered as threat to man and nature. As for, the relating to the human activities and their effects on the environment, they are handled by the implementation of a more rigid model of environmental control and the mobilization of the society in favor of technologies with less energy impact. In view of this scenario, the Proton Exchange Membrane Fuel Cell - PEMFC has been recognized as a key for the vital need of a clean and efficient energy. Considering the conventional power generation system, their advantages during usage configure its application as an ideal option for several utilities, especially in the mobile sector. Even though, the focus on several environmental evaluations in energy systems is referred back to the initial stage of it use, the employment relating to production of the system and to final destination should be considered, since these also present impacts. In the case of PEMFC, their previous and subsequent phases of use are issues related to the platinum catalysts, which indicates an environmental importance that cannot be overlooked. In this sense, the Life Cycle Assessment has been used to understand and to question the risks and opportunities that are associated to certain product, starting from a systemic concept of their relationships with the environment. It is precisely in this context that the present research intends to present its major contribution, starting from an exploratory study towards the its objectives to provide an environmental analysis of such technology linked to post stage of powder-use of the membrane electrode assembly - MEA, concerning the platinum catalysts, on the subject of Life Cycle Assessment - LCA. To attain such aim, the relationships between energy, environment and development are presented and discussed, as well as, the Fuel Cell technology and

  4. "Novos Brasis" em África: desenvolvimento e colonialismo português tardio

    OpenAIRE

    Cláudia Castelo

    2014-01-01

    Este artigo analisa a evolução das ideias e das práticas do Estado colonial português no que toca ao desenvolvimento da "África portuguesa", entre os anos 1930 e 1974. Até aos anos 1960, o esforço modernizador de Portugal nas colónias privilegiou a construção e o melhoramento de infraestruturas. O modelo de desenvolvimento assentava na exploração económica dos recursos naturais e no trabalho forçado dos indígenas, em benefício dos interesses metropolitanos e dos colonos brancos. Depois do iní...

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

    Directory of Open Access Journals (Sweden)

    Mauricio Andreazza Sganderla

    2016-07-01

    Full Text Available 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, tendo como objetivo principal o software em funcionamento e que realmente traga retorno ao cliente.

  6. Metodologia de avaliação e desenvolvimento de grupos de alto desempenho

    Directory of Open Access Journals (Sweden)

    Ana Cristina Carneiro

    2008-11-01

    Full Text Available Este artigo discute a fundamentação teórica do Projeto de Avaliação e Desenvolvimento de Grupos de Alto Desempenho, concebido com base na metodologia da Meta-aprendizagem, e no Modelo Evolutivo, estendido à luz da Teoria da Complexidade. Visa ao desenvolvimento e aplicação de uma metodologia de avaliação/constituição de grupos de alto desempenho no ambiente de pesquisa e pós-graduação. A metodologia proposta validada empiricamente teve base no aproveitamento das virtudes e potencialidades das teorias que lhe deram origem. É destinado aos docentes e pesquisadores de vários campos do conhecimento, bem como aos dirigentes de instituições de educação superior e de pesquisa.

  7. TURISMO E DESENVOLVIMENTO LOCAL DA COMUNIDADE DE PONTA DE PEDRAS/PA: A BUSCA PELA SUSTENTABILIDADE

    OpenAIRE

    Mariani, Milton Pasquoto; Dias, Sibele Amolaro; Silva, Fabricia Gladys

    2008-01-01

    O presente trabalho tem por objetivo analisar a contribuição do turismo no desenvolvimento local da comunidade de Pontas de Pedras, após a implantação dos programas Planos de Desenvolvimento do Pólo de Ecoturismo do Tapajós e Diversificação da Oferta Turística. A atividade turística tem crescido rumo ao interior do Brasil, em função de uma visão empreendedora que vem apostando na conquista de novos mercados através da diversificação de oferta de produtos turísticos. Nesse sentido, esta pesqui...

  8. Efeito de fungos micorrízicos arbusculares no desenvolvimento do abacateiro

    Directory of Open Access Journals (Sweden)

    Silveira Samar Velho da

    2002-01-01

    Full Text Available O objetivo deste trabalho foi determinar a influência da inoculação de seis espécies de fungos micorrízicos arbusculares (FMA (Glomus clarum, G. etunicatum, G. manihotis, Acaulospora scrobiculata, Scutellospora heterogama e Gigaspora margarita sobre o desenvolvimento vegetativo de mudas de abacateiro (Persea sp., nas fases de porta-enxerto, de muda enxertada e de muda no pomar. A influência dos FMA em abacateiros foi variável conforme a espécie do endófito em estudo. As espécies S. heterogama, A. scrobiculata, G. etunicatum e G. clarum colonizaram mais intensamente o sistema radicular dos abacateiros, promovendo melhor desenvolvimento vegetativo das plantas, na fase de porta-enxerto, ao longo do período de produção da muda e após o transplante para pomar.

  9. Dynamic environmental transmission electron microscopy observation of platinum electrode catalyst deactivation in a proton-exchange-membrane fuel cell

    International Nuclear Information System (INIS)

    Spherical-aberration-corrected environmental transmission electron microscopy (AC-ETEM) was applied to study the catalytic activity of platinum/amorphous carbon electrode catalysts in proton-exchange-membrane fuel cells (PEMFCs). These electrode catalysts were characterized in different atmospheres, such as hydrogen and air, and a conventional high vacuum of 10−5 Pa. A high-speed charge coupled device camera was used to capture real-time movies to dynamically study the diffusion and reconstruction of nanoparticles with an information transfer down to 0.1 nm, a time resolution below 0.2 s and an acceleration voltage of 300 kV. With such high spatial and time resolution, AC-ETEM permits the visualization of surface-atom behaviour that dominates the coalescence and surface-reconstruction processes of the nanoparticles. To contribute to the development of robust PEMFC platinum/amorphous carbon electrode catalysts, the change in the specific surface area of platinum particles was evaluated in hydrogen and air atmospheres. The deactivation of such catalysts during cycle operation is a serious problem that must be resolved for the practical use of PEMFCs in real vehicles. In this paper, the mechanism for the deactivation of platinum/amorphous carbon electrode catalysts is discussed using the decay rate of the specific surface area of platinum particles, measured first in a vacuum and then in hydrogen and air atmospheres for comparison. (paper)

  10. Produção de membranas híbridas zirconizadas de SPEEK/Copolissilsesquioxano para aplicação em células a combustível do tipo PEM Production of Zirconized SPEEK/Copolysilsesquioxane hybrid membranes for application in Proton Exchange Membrane fuel cells

    Directory of Open Access Journals (Sweden)

    Kelen R. Aguiar

    2012-01-01

    Full Text Available Membranas baseadas em poli(aril éter cetona sulfonada mostraram ser bastante promissoras para aplicação em células a combustível com membrana trocadora de prótons (PEMFC. O poli(éter-éter-cetona sulfonado (SPEEK, com elevado grau de sulfonação (GS, apresenta alta condutividade de prótons, mas sofre perda de funcionalidade e condutividade em temperaturas altas e umidades baixas. O desenvolvimento de membranas híbridas é uma das possibilidades para melhorar o desempenho destes materiais. Neste trabalho foram preparadas membranas híbridas zirconizadas de SPEEK/copolissilsesquioxano fosfonado (CF por casting, a partir de SPEEK com GS entre 60% e 70% e soluções de cloreto de zirconila (ZrOCl2 1, 5, ou 10% (m/m. As membranas foram caracterizadas por espectroscopia na região do infravermelho (FTIR, difratometria de raios-X (DRX, análise termogravimétrica (TG, calorimetria exploratória diferencial (DSC, condutividade de prótons (σ e microscopia eletrônica de varredura (MEV. A análise por energia dispersiva (EDS confirmou a presença de Zr em domínios esféricos dispersos homogeneamente pelas membranas, enquanto análises de DRX mostraram que os produtos da zirconização são amorfos. Ensaios de impedância eletroquímica indicam aumento da condutividade protônica com a adição de CF e 1 ou 5% de ZrOCl2.Membranes based on sulfonated poly(aryl ether ketone are known to be very promising materials for Proton Exchange Membrane Fuel Cells (PEMFC. Sulfonated poly(ether-ether-ketone (SPEEK, with high sulfonation degrees (SD, present high proton conductivity. However, they lose functionality and conductivity at high temperatures and low humidity. To enhance the performance of these materials, hybrid membranes have gained considerable attention. In this work, zirconized SPEEK/phosphonated copolysilsesquioxane (CF hybrid membranes were prepared by casting, from SPEEK (60% < SD < 70% and 1, 5, or 10 wt. (% zirconyl chloride solutions

  11. Electrochemical behavior of nanocrystalline Ta/TaN multilayer on 316L stainless steel: Novel bipolar plates for proton exchange membrane fuel-cells

    Science.gov (United States)

    Alishahi, M.; Mahboubi, F.; Mousavi Khoie, S. M.; Aparicio, M.; Hübner, R.; Soldera, F.; Gago, R.

    2016-08-01

    Insufficient corrosion resistance and surface conductivity are two main issues that plague large-scale application of stainless steel (SS) bipolar plates in proton exchange membrane fuel cells (PEMFCs). This study explores the use of nanocrystalline Ta/TaN multilayer coatings to improve the electrical and electrochemical performance of polished 316L SS bipolar plates. The multilayer coatings have been deposited by (reactive) magnetron sputtering and characterized by X-ray diffraction, field-emission scanning electron microscopy and transmission electron microscopy. The electrochemical behavior of bare and coated substrates has been evaluated in simulated PEMFC working environments by potentiodynamic and potentiostatic polarization tests at ambient temperature and 80 °C. The results show that the Ta/TaN multilayer coating increases the polarization resistance of 316L SS by about 30 and 104 times at ambient and elevated temperatures, respectively. The interfacial contact resistance (ICR) shows a low value of 12 mΩ × cm2 before the potentiostatic test. This ICR is significantly lower than for the bare substrate and remains mostly unchanged after potentiostatic polarization for 14 h. In addition, the high contact angle (92°) with water for coated substrates indicates a hydrophobic character, which can improve the water management within the cell in PEMFC stacks.

  12. Design and Implementation of 8051 Single-Chip Microcontroller for Stationary 1.0 kW PEM Fuel Cell System

    Directory of Open Access Journals (Sweden)

    Pei-Hsing Huang

    2014-01-01

    Full Text Available Proton exchange membrane fuel cells (PEMFCs have attracted significant interest as a potential green energy source. However, if the performance of such systems is to be enhanced, appropriate control strategies must be applied. Accordingly, the present study proposes a sophisticated control system for a 1.0 kW PEMFC system comprising a fuel cell stack, an auxiliary power supply, a DC-DC buck converter, and a DC-AC inverter. The control system is implemented using an 8051 single-chip microcontroller and is designed to optimize the system performance and safety in both the startup phase and the long-term operation phase. The major features of the proposed control system are described and the circuit diagrams required for its implementation introduced. In addition, the touch-sensitive, intuitive human-machine interface is introduced and typical screens are presented. Finally, the electrical characteristics of the PEMFC system are briefly examined. Overall, the results confirm that the single-chip microcontroller presented in this study has significant potential for commercialization in the near future.

  13. "Novos Brasis" em África: desenvolvimento e colonialismo português tardio

    Directory of Open Access Journals (Sweden)

    Cláudia Castelo

    2014-08-01

    Full Text Available Este artigo analisa a evolução das ideias e das práticas do Estado colonial português no que toca ao desenvolvimento da "África portuguesa", entre os anos 1930 e 1974. Até aos anos 1960, o esforço modernizador de Portugal nas colónias privilegiou a construção e o melhoramento de infraestruturas. O modelo de desenvolvimento assentava na exploração económica dos recursos naturais e no trabalho forçado dos indígenas, em benefício dos interesses metropolitanos e dos colonos brancos. Depois do início da guerra colonial (1961, o discurso e a prática política mudaram, privilegiando a criação de "sociedades multirraciais", através do incremento do povoamento branco. O desenvolvimento social (educação, saúde pública, programas de desenvolvimento comunitário etc. e o bem-estar das populações africanas foram uma preocupação muito tardia do Governo português, se comparada com o que se passou nos impérios inglês ou francês. Esta mudança foi determinada pelo contexto internacional, pelas recomendações da cooperação técnico-científica internacional e por alguns estudos de pesquisadores sociais e agrónomos portugueses.

  14. Desenvolvimento vegetativo de pinhão-manso em diferentes arranjos de plantio em sistemas agrossilvipastoris

    Directory of Open Access Journals (Sweden)

    Marcelo Dias Müller

    2014-07-01

    Full Text Available O objetivo deste trabalho foi avaliar o efeito de diferentes arranjos de plantio no desenvolvimento vegetativo de plantas de pinhão-manso estabelecidas em dois tipos de consórcio agrossilvipastoril. O experimento foi realizado no Município de Coronel Pacheco, MG, em delineamento de blocos ao acaso, em arranjo de parcelas subdivididas. A parcela foi representada por cinco espaçamentos: 6x3 m (555 plantas por hectare, 12x(2x2 m (714 plantas por hectare, 10x(2x2 m (833 plantas por hectare, 8x(2x2 m (1.000 plantas por hectare e 6x1,5 m (1.111 plantas por hectare; e a subparcela, por dois tipos de consórcio: agrossilvipastoril (integração lavoura-pecuária-pinhão-manso e silvipastoril (integração pecuária-pinhão-manso. As avalições foram realizadas nas safras 2010/2011 e 2011/2012. O espaçamento de plantio de 6x3 m proporcionou maior desenvolvimento em diâmetro de copa e número de brotações das plantas de pinhão-manso, na safra 2010/2011. Na safra 2011/2012, foi observado maior desenvolvimento em altura com o espaçamento de plantio de 8x(2x2 m. O consórcio de pinhão-manso x milho x pastagem proporciona maior desenvolvimento das plantas de pinhão-manso para todas as variáveis estudadas nas duas safras.

  15. Desenvolvimento do WHOQOL, módulo espiritualidade, religiosidade e crenças pessoais

    Directory of Open Access Journals (Sweden)

    Fleck Marcelo Pio da Almeida

    2003-01-01

    Full Text Available OBJETIVO: Descrever o desenvolvimento do módulo "espiritualidade, religiosidade e crenças pessoais" pelo instrumento WHOQOL-SRPB e relatar os principais achados da pesquisa realizada com grupos focais constituídos por pessoas representativas das práticas religiosas mais freqüentes, pacientes e profissionais da saúde. MÉTODOS: São descritas as várias etapas de desenvolvimento do instrumento WHOQOL-SRPB: revisão da literatura, grupos focais, geração de questões nacionais, geração de itens consensuais, desenvolvimento do instrumento piloto, aplicação do piloto, análise do desempenho das questões, desenvolvimento do instrumento definitivo e teste de campo. A etapa dos grupos focais foi aplicada em Porto Alegre, RS, com 15 grupos (n=142, incluindo profissionais da saúde, pacientes agudos, crônicos e terminais, religiosos (católicos, evangélicos, afro-brasileiros e espíritas e ateus. Foram discutidas as facetas sugeridas pelo grupo de experts, além das dimensões espontaneamente trazidas pelos participantes dos grupos. RESULTADOS E CONCLUSÕES: A técnica de grupo focal mostrou-se adequada para captar as diferentes opiniões dos participantes, permitindo que fossem testadas as hipóteses dos pesquisadores, redirecionando e/ou ampliando conceitos previamente estabelecidos. Além disso, evidenciou a importância da dimensão espiritual na vida dos pacientes.

  16. 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...... significant attention in recent years because of its potential advantages such as high CO tolerance, easy cooling, better heat utilization and possible integration with fuel processing units. However, the high temperature obviously aggravates the carbon corrosion and catalyst degradation. Based on thermally...

  17. Advances in PEM fuel cells with CFD techniques

    Energy Technology Data Exchange (ETDEWEB)

    Robalinho, Eric; Cunha, Edgar Ferrari da; Zararya, Ahmed; Linardi, Marcelo [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)], Email: eric@ipen.br; Cekinski, Efrain [Instituto de Pesquisas Tecnologicas (IPT), Sao Paulo, SP (Brazil)

    2010-07-01

    This paper presents some applications of computational fluid dynamics techniques in the optimization of Proton Exchange Membrane Fuel Cell (PEMFC) designs. The results concern: modeling of gas distribution channels, the study for both porous anode and cathode and the three-dimensional modeling of a partial geometry layer containing catalytic Gas Diffusion Layers (GDL) and membrane. Numerical results of the simulations of graphite plates flow channels, using ethanol as fuel, are also presented. Some experimental results are compared to the corresponding numerical ones for several cases, demonstrating the importance and usefulness of this computational tool. (author)

  18. Characterising of solid state electrochemical cells under operation

    DEFF Research Database (Denmark)

    Holtappels, Peter

    2014-01-01

    Compared to significant progress in PEMFC especially regarding the utilization of complex fuels such as methanol significant progress has been made by applying spectroscopic / differential IR and spectrometric techniques to working fuel cells, the processes in solid state high temperature....... This relates to interrelation between NOx/ O2 on cathodes but also to sulfur and carbon exposure at the anode. Past and recent activities on SOFC anodes and cathodes will be presented as well as perspectives and gaps discussed for these systems. Especially interaction between sulfur interactions with solids...

  19. POLÍTICAS PÚBLICAS E CAPITAL HUMANO PARA O DESENVOLVIMENTO LOCAL DA PESCA ARTESANAL

    Directory of Open Access Journals (Sweden)

    João Henrique de Melo Ferraz

    2014-10-01

    Full Text Available Este trabalho identifica e analisa as políticas públicas de extensão pesqueira para o desenvolvimento local do Município de Porto de Pedras, Alagoas, entre 2003 e 2009, por meio dos projetos estabelecidos pelo governo. Especificamente, se analisa o capital humano da colônia de pescadores Z-25, frente aos projetos tecnológicos ligados à pesca artesanal. A metodologia utilizada neste trabalho foi a identificação das políticas públicas para o desenvolvimento da pesca artesanal, além de aplicação de questionários semiestruturados com os gestores e técnicos do MPA e da SEAGRI/AL, e pescadores da colônia. Tais entrevistas tiveram a finalidade de analisar o capital humano e de compreender como essas políticas de inovação tecnológicas são incorporadas na pesca. Com os dados identificou-se uma carência de políticas públicas que associem o fomento do capital humano da pesca artesanal com o desenvolvimento local.

  20. Estratégia de desenvolvimento de marcas próprias por supermercados no Brasil.

    Directory of Open Access Journals (Sweden)

    Jorge Antonio Appollo Unterleider

    2006-09-01

    Full Text Available As empresas de varejo no Brasil, em especial os supermercados, vêm adotando práticas com o intuito de conquistar e fidelizar consumidores e, ao mesmo tempo, diferenciar-se dos concorrentes. O acirramento da competição entre os supermercados força a busca por alternativas com capacidade de fortalecer o posicionamento diante de seus concorrentes e também dos fabricantes tradicionais de produtos com marcas conhecidas. Entre as ações desenvolvidas para esse fim, alguns supermercados investem no desenvolvimento de produtos com suas marcas, os produtos com marca própria de supermercados. Neste sentido, este estudo busca analisar o processo de desenvolvimento desses produtos, desde as motivações estratégicas até os resultados que vêm sendo obtidos. Foram pesquisados cinco supermercados por meio da abordagem de estudo de casos, utilizando múltiplas fontes de evidências. Os resultados encontrados mostram que os supermercados desenvolvem produtos com suas marcas principalmente a fim de fidelizar o consumidor, aumentar seu lucro e elevar o poder de barganha junto aos fornecedores tradicionais. Também foi identificado um apelo social motivador no processo de desenvolvimento desses produtos.

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

    Directory of Open Access Journals (Sweden)

    Miguel Paulo A. Cauchick

    2003-01-01

    Full Text Available 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 conceito do QFD, citando uma aplicação em uma empresa que produz filmes flexíveis de polipropileno (BOPP. O trabalho apresenta alguns aspectos da introdução do método na empresa, apontando as dificuldades encontradas, resultados e benefícios decorrentes da implantação. Dentre os benefícios gerados, destacam-se a importância do papel do QFD como um método para sistematizar o processo de desenvolvimento, bem como outros benefícios para a equipe, tais como melhoria nas habilidades de planejamento, disseminação do conhecimento e melhoria de comunicação entre as áreas funcionais.

  2. Análise de instrumentos para triagem do desenvolvimento infantil

    Directory of Open Access Journals (Sweden)

    Ana Regina Lucato Sigolo

    2011-04-01

    Full Text Available A literatura mostra a importância da identificação precoce de sinais de atraso no desenvolvimento infantil e a dificuldade na escolha de instrumentos de avaliação. Os objetivos foram comparar o Denver II e a EDC com uma escala de referência (EEDP quanto à identificação de crianças com atraso de desenvolvimento, verificar diferença nos resultados considerando gênero dos participantes e averiguar a convergência dos resultados das escalas. Participaram 24 bebês de cinco a onze meses, de ambos os sexos, frequentadores de creches municipais. Os instrumentos foram aplicados individualmente e em sequência pré-definida. A análise estatística revelou que a escala EDC e o Denver II não podem ser considerados semelhantes à escala EEDP. Quanto ao gênero, não houve diferença significativa. Não houve convergência de itens falhos segundo as áreas. Assim, é importante ter cautela na escolha de instrumentos para triagem e obter informações de diferentes fontes sobre o desenvolvimento da criança.

  3. Cultura e desenvolvimento humano: saberes divulgados em um impresso brasileiro do século XIX

    Directory of Open Access Journals (Sweden)

    Raquel Martins de Assis

    2012-08-01

    Full Text Available Este artigo descreve resultados de pesquisa sobre as relações entre cultivo das faculdades da alma e educação na cultura impressa do século XIX, no Brasil, mais especificamente em Minas Gerais. Trata-se de um estudo em história da psicologia da educação com o objetivo de investigar as relações entre concepções sobre desenvolvimento humano, faculdades intelectuais e morais e discurso educativo presentes na cultura impressa. O texto apresenta a análise da Secção Scientífica ou Pedagogia, redigida por José Miguel de Siqueira e publicada no jornal O Baependyano (1877-1889. Na Secção, a pedagogia, vista como moderna, é definida como alargamento e expansão das forças da alma humana, evidenciando relações entre desenvolvimento humano e educação. O desenvolvimento, por sua vez, é dirigido por formas específicas de cultura. Para a conceituação de educação, bem como de cultura, Siqueira apropria-se de ideias francesas divulgadas na época, assim como de tradições já bem solidificadas na província, como os ideais católicos.

  4. Uso de esterco no desenvolvimento de mudas de mamoeiro colonizadas com fungos micorrízicos

    Directory of Open Access Journals (Sweden)

    TRINDADE ALDO VILAR

    2000-01-01

    Full Text Available O trabalho objetivou a adequação de esterco na composição do substrato para produção de mudas de mamoeiro (Carica papaya L., que permita o melhor estabelecimento da simbiose micorrízica e sua expressão no desenvolvimento da muda. Foram testadas cinco doses de esterco no substrato (0, 5, 10, 20 e 30% e a inoculação ou não de Glomus etunicatum. Após 50 dias de cultivo concluiu-se que: o esterco promove máximo desenvolvimento das mudas nas doses de 20% e 30%; a adição de P e K não resulta em benefícios adicionais no crescimento das mudas; a inoculação de G. etunicatum é eficiente para o desenvolvimento da muda até a dose de 10% de esterco; o fungo coloniza as mudas em doses de até 30% de esterco, mas com tendência decrescente; a combinação de 10% de esterco e inoculação do fungo micorrízico arbuscular promove a formação de plantas sadias, sem sintomas de deficiência nutricional e apropriadas para o transplantio ao campo.

  5. ATIVIDADES CORPORAIS AQUÁTICAS EM ESPECIAL O MERGULHO E O DESENVOLVIMENTO DO PSIQUISMO

    Directory of Open Access Journals (Sweden)

    Celi Taffarel

    2015-04-01

    Full Text Available O presente estudo situa-se entre os que investigam o desenvolvimento do psiquismo ressaltando o papel da educação escolar e o acesso ao conhecimento clássico sobre as atividades corporais aquáticas, e dentre elas o mergulho, no desenvolvimento dos processos funcionais, através do ensino e da aprendizagem de conteúdos nucleares na escola. Objetivo:Analisar o desenvolvimento do psiquismo à luz da psicologia histórico-cultural e propor o trato com o conhecimento clássico sobre atividades aquáticas, em especial o mergulho, a luz da pedagogia histórico-critica, defendendo este conhecimento como nuclear no currículo escolar, nos estudos sobre a relação “ser humano-água”, para a elevação da capacidade teórica dos estudantes, através da metodologia do ensino critico-suparadora.

  6. Fuel cell technology for cogeneration systems. Symposium. Proceedings; Brennstoffzellen - Technologie fuer Blockheizkraftwerke. Symposium. Dokumentation

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2001-07-01

    This proceedings volume contains 11 papers on the following subject: Competence network 'Fuel Cells' in Nordrhein-Westfalen (D. Stolten, Juelich Research Center); Fuel cells in stationary applications (B. Hoehlein, Juelich Research Center); Functional principles of energy conversion in fuel cells (W. Schnurnberger, DLR); Low-temperature fuel cells AFC, PEMFC, PAFC (M. Waidhas, Siemens); High-temperature fuel cells - SOFC, MCFC (D. Stolten); Power plant options - natural gas, hydrogen, etc. (R. Wurster, Ludwig-Boelkow-Systemtechnik); Fuel cell supply (A. Heizel, ISE); Hydrogen-fuelled cogeneration units (G. Gummert Hamburg Gas Consult); SOFC high-temperature fuel cells for domestic power supply (R. Diethelm, Sulzer-Hexis); PEFC low-temperature fuel cells for domestic power supply (K. Klinder, Vaillant); Fuel cells, a chance for local utilities (B. Vogel, WINGAS). [German] Dieser Tagungsband enthaelt 11 Beitraege zu folgenden Themen: Kompetenznetzwerk Brennstoffzelle in NRW (D. Stolten, Forschungszentrum Juelich); Brennstoffzellen in der stationaeren Anwendung (B. Hoehlein, Forschungszentrum Juelich); Funktionsprinzipien der Energieumwandlung in Brennstoffzellen (W. Schnurnberger, DLR); Niedertemperaturbrennstoffzellen - AFC, PEMFC, PAFC (M. Waidhas, Siemens); Hochtemperaturbrennstoffzellen - SOFC, MCFC (D. Stolten); Kraftstoffoptionen- Erdgas, Wasserstoff u.a. (R. Wurster, Ludwig-Boelkow-Systemtechnik); Brennstoffbereitstellung (A. Heinzel, ISE); Wasserstoffbetriebene BHKW (G. Gummert Hamburg Gas Consult); Hochtemperaturbrennstoffzelle SOFC fuer die Hausenergieversorgung (R. Diethelm, Sulzer-Hexis); Niedertemperaturbrennstoffzelle PEFC fuer die Hausenergieversorgung (K. Klinder, Vaillant); Brennstoffzelle als Chance fuer lokale EVUs (B. Vogel, WINGAS).

  7. Cost analysis of electrical power from an ethanol reformer and the fuel cell in the development of productive activities in the community Pico do Amor, MT, Brazil; Analise do custo da energia eletrica proveniente de um reformador de etanol e celula a combustivel no desenvolvimento de atividades produtivas na comunidade Pico do Amor/MT

    Energy Technology Data Exchange (ETDEWEB)

    Lopes, Davi Gabriel; Teixeira, Andre Frazao; Lopes, Daniel Gabriel; Cavaliero, Carla Kazue Nakao [Universidade Estadual de Campinas (DE/FEM/UNICAMP), SP (Brazil). Faculdade de Engenharia Mecanica. Departamento de Energia; Instituto Aqua Genesis, Campinas, SP (Brazil); Hytron, Campinas, SP (Brazil)

    2010-07-01

    This work has the objective to analyze the impact of the cost of from an ethane reformer / fuel cell in the family income considering the development of two productive activities selected by the community itself: the production and marketing of cassava flour and 'rapadura', a typical brazilian candy. The community energy demand was analyzed to achieve the results; estimated the energy cost from the implemented system and the money from the selling of the cassava flour and 'rapadura' produced with this electricity; the study of sensibility of the ethanol price in the electrical energy cost was done too, and the cassava flour and 'rapadura' in the family funds. From the results, it was verified that the electrical energy cost has a 16,4% impact in the family gross income and a net value around R$ 260,85/family, indicating that the community will have enough funds to pay for the energy and also will rise the amount of money for each family. Besides, the comparative analyze of the cost of the electricity from the ethanol/fuel cell reformer and photovoltaic systems shows that, considering only the maintenance and operation costs, the first one should be more attractive than the second one. (author)

  8. Fatores prognósticos para o desenvolvimento cognitivo de prematuros de muito baixo peso

    Directory of Open Access Journals (Sweden)

    Maria Dalva Barbosa Baker Méio

    2003-06-01

    Full Text Available OBJETIVO: Crianças prematuras, de muito baixo peso, podem apresentar alterações em seu desenvolvimento cognitivo. No Brasil, pouco se conhece sobre a evolução dessas crianças na idade pré-escolar. O objetivo do estudo foi descrever o desenvolvimento cognitivo de uma população de recém-nascidos prematuros de muito baixo peso e verificar possíveis fatores prognósticos para desenvolvimento cognitivo anormal. MÉTODOS: Um estudo de coorte foi realizado com uma população de crianças pré-escolares, nascidas prematuras, de muito baixo peso, entre janeiro de 1991 e setembro de 1993. O desenvolvimento cognitivo foi avaliado por meio do teste WPPSI-R (Wechsler Preschool and Primary Intelligence Scales aplicado por psicólogas, utilizando dois pontos de corte para definição de anormalidade: escores abaixo de 1 e 2, desvios padrões da média (DP. RESULTADOS: Foram avaliadas 79 crianças de quatro a cinco anos de idade. A média do escore total do teste WIPPSI-R foi de 75,6 (±11,9. A incidência de escore total anormal foi de 77,2% e de 32,9% (1DP e 2 DP, respectivamente. Após o ajuste por "tipo de parto", ser pequeno para a idade gestacional (OR=6,19; IC95% 1,60-23,86, ultra-som transfontanela anormal (OR=5,90; IC95% 1,04-9,83 e ser do sexo masculino (OR=3,20; IC 95% 1,32-26,35 foram os fatores que predisseram escore total <70 (2 DP. CONCLUSÃO: Houve maior comprometimento do desenvolvimento cognitivo nas crianças estudadas do que o descrito na literatura. Ser pequeno para idade gestacional, ultra-som transfontanela anormal e sexo masculino foram fatores prognósticos de pior evolução.

  9. DESENVOLVIMENTO LOCAL E MANEJO DA CAATINGA NO ASSENTAMENTO HIPÓLITO, EM MOSSORÓ/RN

    Directory of Open Access Journals (Sweden)

    E. D. G. Pereira

    2007-12-01

    Full Text Available Nas últimas décadas tem havido uma preocupação muito grande com o tipo de desenvolvimento que vem sendo implementado pelos governos. A partir daí, criou-se a noção de desenvolvimento sustentável, o qual se baseia em um crescimento econômico que seja acompanhado por eqüidade social e prudência ecológica. Em muitos projetos de assentamentos têm sido desenvolvidos pesquisas com o objetivo de analisar como vem se processando tais experiências. Nossa investigação teve como meta verificar os impactos sócio-ambientais trazidos a partir do uso da caatinga no assentamento Hipólito, no município de Mossoró, no Oeste do RN. Preocupou-nos saber se naquele projeto de assentamento tem ocorrido um desenvolvimento local, baseado em critérios de sustentabilidade. A metodologia empregada foi a realização de entrevistas com 29 assentados, o que corresponde a 20% da população total do assentamento, além de leituras de outros trabalhos e artigos de jornais. O trabalho está em fase de conclusão, porém a partir de estudos de campo, realizados no mês de agosto de 2004, podemos apresentar os seguintes resultados: quanto ao aspecto sócio-econômico, os assentados têm na agricultura de sequeiro a atividade econômica principal; a produtividade é baixa e a renda é complementada com “bicos”, aposentadorias e/ou com o dinheiro advindo dos planos de assistência social do Governo Federal; a agricultura é realizada sem os devidos cuidados com o meio ambiente, e o desmatamento desordenado tem agravado ainda mais os problemas presentes no bioma caatinga, tais como salinização, a desertificação e o desaparecimento de espécies da fauna e da flora. Face ao exposto, podemos concluir que a realidade observada no assentamento aponta para a insustentabilidade sócio-econômica e ambiental naquela área. Palavras-chave: sustentabilidade; caatinga; assentamento; desenvolvimento rural; desenvolvimento local.

  10. A taxa de câmbio no centro da teoria do desenvolvimento

    Directory of Open Access Journals (Sweden)

    Luiz Carlos Bresser-Pereira

    2012-08-01

    Full Text Available Este artigo apresenta as principais ideias da macroeconomia estruturalista do desenvolvimento - a teoria por trás de novo-desenvolvimentismo. Seu foco é a taxa de câmbio que é pela primeira vez colocada no centro da economia do desenvolvimento. A teoria econômica geralmente vê a taxa de câmbio como um problema de curto prazo a ser discutido na macroeconomia. A macroeconomia estruturalista do desenvolvimento mostra que há, nos países em desenvolvimento, a tendência à sobreapreciação cíclica da taxa de câmbio causada pela falta de neutralização da doença holandesa e por entradas de capital excessivas. Em consequência, considera a taxa de câmbio cronicamente sobreapreciada e, por isso, um grande obstáculo ao crescimento econômico. No processo de desenvolvimento, a taxa de câmbio tem a função de um interruptor de luz que conecta ou desconecta as empresas nacionais que utilizam a tecnologia no estado da arte mundial dos mercados mundiais.This paper presents the main ideas of structuralist development macroeconomics - the theory behind new developmentalism. Its focus is on the exchange rate that is positioned for the first time in the core of development economics. Economic theory usually views the exchange rate as a short term problem to be discussed in open macroeconomics. Structuralist development macroeconomics argues that there is in developing countries a tendency to the cyclical overvaluation of the exchange rate caused by the lack of neutralization of the Dutch disease and by excessive capital inflows. In consequence it views the exchange rate as chronically overvalued, and, for that reason, a major obstacle to economic growth. In the development process, the exchange rate has the role of light switch that connects or disconnects the national business enterprises utilizing technology in the world state of the art from world markets.

  11. Estudo longitudinal do desenvolvimento da comunicação em diversas economias mundiais.

    Directory of Open Access Journals (Sweden)

    Emílio José Montero Arruda Filho

    2012-08-01

    Full Text Available O desenvolvimento do setor de comunicação de um país possui relações com o seu desenvolvimento econômico e é possível demonstrar essa conexão estatisticamente, como tem sido feito por pesquisadores de instituições como a ITU (International Telecommunications Union. Como esses dados estão apenas apresentados na forma simples e não levam em conta fatores de interconexão, é importante desenvolver pesquisas que avaliem a conexão entre variáveis relevantes no campo. Este trabalho visa analisar os fatores de desenvolvimento tecnológico de comunicação que melhor descrevem o posicionamento econômico de um país, integrando a usabilidade dos serviços de comunicação com o status econômico. Foram utilizados dados de 56 países, escolhidos aleatoriamente. Uma pesquisa na forma de datamining foi realizada, a qual analisou os dados existentes já previamente coletados por instituições de pesquisa tais como ITU, World Bank, e outras. Cada fator de usabilidade, preferência e serviço analisado é apontado como um reflexo de outros serviços e usos anteriormente desenvolvidos. Parte da literatura sobre esse tópico (ARRUDA FILHO; CASSIA; MARINO, 2008; CHERRY, 2007; DAVIES; HARDT; KELLY, 2004 argument que o desenvolvimento econômico de certos países existe como resultado de um aumento do desenvolvimento tecnológico, porém outras demonstram ou informam o contrário. Este artigo apresenta essas relações em certos países, escolhidos pela quantidade de informação disponível considerando sua posição de desenvolvimento global, relacionando diretamente o comportamento de crescimento ou redução no uso das tecnologias, tais como telefone e internet. Este trabalho coletou dados de duas fontes mundiais de informação dos setores mencionados: a International Telecommunications Union (ITU e o World Bank. Utilizaram-se as técnicas estatísticas de regressão e análise de variância para a análise de dados de 56 países ao longo de

  12. Improved Electrodes for High Temperature Proton Exchange Membrane Fuel Cells using Carbon Nanospheres.

    Science.gov (United States)

    Zamora, Héctor; Plaza, Jorge; Cañizares, Pablo; Lobato, Justo; Rodrigo, Manuel A

    2016-05-23

    This work evaluates the use of carbon nanospheres (CNS) in microporous layers (MPL) of high temperature proton exchange membrane fuel cell (HT-PEMFC) electrodes and compares the characteristics and performance with those obtained using conventional MPL based on carbon black. XRD, hydrophobicity, Brunauer-Emmett-Teller theory, and gas permeability of MPL prepared with CNS were the parameters evaluated. In addition, a short life test in a fuel cell was carried out to evaluate performance under accelerated stress conditions. The results demonstrate that CNS is a promising alternative to traditional carbonaceous materials because of its high electrochemical stability and good electrical conductivity, suitable to be used in this technology.

  13. Inorganic-organic Composite Membranes with Novel Microstructure for High Temperature Proton Exchange Membrane Fuel Cells

    Institute of Scientific and Technical Information of China (English)

    Zhigang Ma; Jiandong Gao; Jing Guo; Zhenghua Deng; Jishuan Suo

    2007-01-01

    Nowadays,more and more fossil fuels are consumed and air pollurion has become a threat to the survival of people.Therefore,we need some other power sources to provide energy without damaging the environment.Proton exchange membrane fuel cells(PEMFCs)have received wide attention due to their advantages Such as high energy density and zero emission[1].Particularly, direct methanol fuel cells (DMFCs)were considered as the most suitable energy sources for electric vehicles(EVs)and portable electronics.

  14. O Planeamento Territorial como um Instrumento de Política para Operacionalização do Desenvolvimento Sustentável

    OpenAIRE

    Cunha, Maria Luísa S. Oliveira e

    2000-01-01

    São várias e diversificadas as definições que podemos encontrar na literatura para o conceito de Desenvolvimento Sustentável: … "É o desenvolvimento que vai de encontro às necessidades das gerações presentes sem comprometer a capacidade de desenvolvimento das gerações futuras." (WCED, 1987) … "Não é um estado fixo de harmonia, mas sim um processo de mudança no qual a exploração dos recursos, o direccionamento dos investimentos, as orientações do desenvolvimento tecnológico e as mudanças...

  15. Stereochemistry-Dependent Proton Conduction in Proton Exchange Membrane Fuel Cells.

    Science.gov (United States)

    Thimmappa, Ravikumar; Devendrachari, Mruthyunjayachari Chattanahalli; Kottaichamy, Alagar Raja; Tiwari, Omshanker; Gaikwad, Pramod; Paswan, Bhuneshwar; Thotiyl, Musthafa Ottakam

    2016-01-12

    Graphene oxide (GO) is impermeable to H2 and O2 fuels while permitting H(+) shuttling, making it a potential candidate for proton exchange membrane fuel cells (PEMFC), albeit with a large anisotropy in their proton transport having a dominant in plane (σIP) contribution over the through plane (σTP). If GO-based membranes are ever to succeed in PEMFC, it inevitably should have a dominant through-plane proton shuttling capability (σTP), as it is the direction in which proton gets transported in a real fuel-cell configuration. Here we show that anisotropy in proton conduction in GO-based fuel cell membranes can be brought down by selectively tuning the geometric arrangement of functional groups around the dopant molecules. The results show that cis isomer causes a selective amplification of through-plane proton transport, σTP, pointing to a very strong geometry angle in ionic conduction. Intercalation of cis isomer causes significant expansion of GO (001) planes involved in σTP transport due to their mutual H-bonding interaction and efficient bridging of individual GO planes, bringing down the activation energy required for σTP, suggesting the dominance of a Grotthuss-type mechanism. This isomer-governed amplification of through-plane proton shuttling resulted in the overall boosting of fuel-cell performance, and it underlines that geometrical factors should be given prime consideration while selecting dopant molecules for bringing down the anisotropy in proton conduction and enhancing the fuel-cell performance in GO-based PEMFC.

  16. Parameter extraction of different fuel cell models with transferred adaptive differential evolution

    International Nuclear Information System (INIS)

    To improve the design and control of FC (fuel cell) models, it is important to extract their unknown parameters. Generally, the parameter extraction problems of FC models can be transformed as nonlinear and multi-variable optimization problems. To extract the parameters of different FC models exactly and fast, in this paper, we propose a transferred adaptive DE (differential evolution) framework, in which the successful parameters of the adaptive DE solving previous problems are properly transferred to solve new optimization problems in the similar problem-domains. Based on this framework, an improved adaptive DE method (TRADE, in short) is presented as an illustration. To verify the performance of our proposal, TRADE is used to extract the unknown parameters of two types of fuel cell models, i.e., PEMFC (proton exchange membrane fuel cell) and SOFC (solid oxide fuel cell). The results of TRADE are also compared with those of other state-of-the-art EAs (evolutionary algorithms). Even though the modification is very simple, the results indicate that TRADE can extract the parameters of both PEMFC and SOFC models exactly and fast. Moreover, the V–I characteristics obtained by TRADE agree well with the simulated and experimental data in all cases for both types of fuel cell models. Also, it improves the performance of the original adaptive DE significantly in terms of both the quality of final solutions and the convergence speed in all cases. Additionally, TRADE is able to provide better results compared with other EAs. - Highlights: • A framework of transferred adaptive differential evolution is proposed. • Based on the framework, an improved differential evolution (TRADE) is presented. • TRADE obtains very promising results to extract the parameters of PEMFC and SOFC models

  17. Corrosion and electrical properties of CrN- and TiN-coated 316L stainless steel used as bipolar plates for polymer electrolyte membrane fuel cells

    International Nuclear Information System (INIS)

    Cathode arc ion plating was applied to deposit CrN and TiN coating layers on stainless steel 316L (SS316L) to produce metallic bipolar plates for polymer electrolyte membrane fuel cells (PEMFCs). The interfacial contact resistance between samples and carbon paper was measured and found to be 10 and 23 mΩ ∗ cm2 for TiN and CrN coating layer respectively under 150 N cm−2 compaction forces. The corrosion properties were investigated in the operating environments of PEMFC. While TiN coating layer was dissolved in the operating environments of PEMFC, the corrosion current density of 0.1 μA cm−2 was obtained for CrN coating layer at anodic condition and its protective efficiency was revealed as 99%. This analysis indicates that the improvement may be attributed to the extremely dense coating and the synergistic function of the CrN layered structure. - Highlights: ► CrN and TiN are deposited on the surface of SS316L by cathode arc ion plating. ► Coating layers of CrN and TiN lead to high electrical conductivity. ► CrN coating layer provides higher corrosion resistance than TiN coating layer

  18. Surface characteristic of chemically converted graphene coated low carbon steel by electro spray coating method for polymer electrolyte membrane fuel cell bipolar plate.

    Science.gov (United States)

    Kim, Jungsoo; Kim, Yang Do; Nam, Dae Geun

    2013-05-01

    Graphene was coated on low carbon steel (SS400) by electro spray coating method to improve its properties of corrosion resistance and contact resistance. Exfoliated graphite was made of the graphite by chemical treatment (Chemically Converted Graphene, CCG). CCG is distributed using dispersing agent, and low carbon steel was coated with diffuse graphene solution by electro spray coating method. The structure of the CCG was analyzed using XRD and the coating layer of surface was analyzed using SEM. Analysis showed that multi-layered graphite structure was destroyed and it was transformed in to fine layers graphene structure. And the result of SEM analysis on the surface and the cross section, graphene layer was uniformly formed with 3-5 microm thickness on the surface of substrate. Corrosion resistance test was applied in the corrosive solution which is similar to the polymer electrolyte membrane fuel cell (PEMFC) stack inside. And interfacial contact resistance (ICR) test was measured to simulate the internal operating conditions of PEMFC stack. As a result of measuring corrosion resistance and contact resistance, it could be confirmed that low carbon steel coated with CCG was revealed to be more effective in terms of its applicability as PEMFC bipolar plate. PMID:23858864

  19. Two-dimensional modeling of a polymer electrolyte membrane fuel cell with long flow channel. Part II. Physics-based electrochemical impedance analysis

    Science.gov (United States)

    Bao, Cheng; Bessler, Wolfgang G.

    2015-03-01

    The state-of-the-art electrochemical impedance spectroscopy (EIS) calculations have not yet started from fully multi-dimensional modeling. For a polymer electrolyte membrane fuel cell (PEMFC) with long flow channel, the impedance plot shows a multi-arc characteristic and some impedance arcs could merge. By using a step excitation/Fourier transform algorithm, an EIS simulation is implemented for the first time based on the full 2D PEMFC model presented in the first part of this work. All the dominant transient behaviors are able to be captured. A novel methodology called 'configuration of system dynamics', which is suitable for any electrochemical system, is then developed to resolve the physical meaning of the impedance spectra. In addition to the high-frequency arc due to charge transfer, the Nyquist plots contain additional medium/low-frequency arcs due to mass transfer in the diffusion layers and along the channel, as well as a low-frequency arc resulting from water transport in the membrane. In some case, the impedance spectra appear partly inductive due to water transport, which demonstrates the complexity of the water management of PEMFCs and the necessity of physics-based calculations.

  20. BIOFERTILIZANTE E ADUBAÇÃO MINERAL NO DESENVOLVIMENTO DA BIOFERTILIZANTE E ADUBAÇÃO MINERAL NO DESENVOLVIMENTO DA LÂMINAS DE ÁGUA

    OpenAIRE

    Fabio Olivieiri de Nobile; João Antonio Galbiatti; Reginaldo Itiro Muraishi; Thais Botamede Spadoni

    2012-01-01

    Com a finalidade de se quantificar os efeitos de diferentes níveis de água, adubação orgânica (efluentede biodigestor) e adubação mineral sobre o desenvolvimento da cultura de cebola (Allium cepa L.), realizou-se apresente pesquisa no Departamento de Engenharia Rural da FCAV/UNESP- SP/Brasil. Para alcançar os objetivospropostos, submeteu-se a cultura de cebola a diferentes níveis de água, fazendo-se também uso da adubação orgânica(na dose de 60 m³ há ˉ¹) e mineral (convencional), para efeito ...