IRANIAN FUEL CELL SEMINAR | Year:2010 | دوره:4 |Papers Count:36

THE ELECTRICAL CONDUCTIVITY OF AISI 430 FERRITIC STAINLESS STEEL WHICH IS USED AS AN INTERCONNECT IN SOLID OXIDE FUEL CELLS (SOFCS) FOR INTERMEDIATE TEMPERATURE OPERATION, CAN BE IMPROVED WITH A CONDUCTIVE COATING LAYER. IN THIS STUDY, AISI 430 FERRITIC STAINLESS STEEL WAS COATED IN A MN-BASE PACK MIXTURE BY PACK CEMENTATION METHOD. AS-COATED SPECIMENS WERE CHARACTERIZED USING SCANNING ELECTRON MICROSCOPY (SEM).ELECTRICAL CONDUCTIVITY OF THE COATED COUPONS WAS TESTED AS A FUNCTION OF TEMPERATURE BY OXIDIZING THE SAMPLES FROM ROOM TEMPERATURE TO 700OC. ALSO ELECTRICAL CONDUCTIVITY HAS BEEN EVALUATED AS A FUNCTION OF OXIDATION TIME DURING ISOTHERMAL OXIDATION AT 700OC. RESULTS SHOWED THE INCREASE OF TEMPERATURE CAUSED TO THE DECREASE OF ELECTRICAL CONDUCTIVITY AND ALSO, THE COATING LAYER TRANSFORMED TO MANGANESE SPINELS DURING ISOTHERMAL OXIDATION. SPINELS AMELIORATED THE ELECTRICAL CONDUCTIVITY OF COATED COUPONS (69 S.CM-1) COMPARED TO UNCOATED ONES (32 S.CM-1) AFTER 200 H OXIDATION AT 700OC.

AN ELECTROCHEMICAL METHOD WAS DEVELOPED TO DEPOSIT PLATINUM (PT)-NICKEL (NI) ALLOY NANOPARTICLES ON CARBON-CERAMIC ELECTRODE (PT-NI/CCE). THE MATERIAL WAS CHARACTERIZED BY VARIOUS METHODS INCLUDING SCANNING ELECTRON MICROSCOPE, EDX ANALYSIS, AND ELECTROCHEMICAL TECHNIQUES. AN APPRECIABLY IMPROVED CATALYSIS TOWARD OXIDATION OF METHANOL WAS OBSERVED AT THE PT-NI/CCE NANOPARTICLES (REAL RATIO OF PT-NI OF » 1:1), WHICH WAS INTERPRETED BY A MECHANISM BASED ON THE BIFUNCTIONAL CATALYSIS. THE SUCCESSFUL PREPARATION OF PT-NI/CCE NANOPARTICLES OPENS A NEW PATH TO SYNTHESIZE THE PROMISING CATALYSTS FOR METHANOL. IT WAS SHOWN THAT THE PT-NI/CCE NANOPARTICLES WERE THE MOST EFFICIENT CATALYST IN THE OXIDATION OF METHANOL MAKING IT MORE ATTRACTIVE FOR FUEL CELL APPLICATIONS. THE EFFECTIVE PARAMETERS ON ELECTROCATALYTIC OXIDATION OF METHANOL WERE INVESTIGATED AND THE RESULTS WERE DISCUSSED. FINALLY, THE LONG-TERM STABILITY OF THE MODIFIED ELECTRODE HAS ALSO BEEN INVESTIGATED.

A FILM OF PANI NANOWIRES (PANI (NWS)) WAS DEPOSITED ONTO THE SURFACE OF A STAINLESS STEEL ELECTRODE VIA CYCLIC VOLTAMMETRY. DURING THE POLYMERIZATION OF ANILINE (ANI), PANI( NWS) WERE DOPED WITH TRIFLUOROMETHANE SULFONIC ACID, AND THE DOPED PANI WERE UTILIZED FOR THE FABRICATION OF A VULCAN (C) PANI COMPOSITE. PT PARTICLES WERE SUBSEQUENTLY DEPOSITED BY REDUCTION ONTO THE CPANI COMPOSITE TO PRODUCE A PT/C-PANI ELECTROCATALYST. THE ELECTRODES ARE CHARACTERIZED BY CYCLIC VOLTAMMETRY, CURRENT–POTENTIAL MEASUREMENTS, ELECTROCHEMICAL IMPEDANCE SPECTROSCOPY, AND CHRONOAMPEROMETRY. THE POLYANILINE IS FOUND TO BE HOMOGENOUSLY DISPERSED IN THE CATALYST LAYER, MAKING IT A GOOD CANDIDATE PROTON AND ELECTRON CONDUCTOR. USE OF POLYANILINE INSTEAD OF NAFION IN THE CATALYST LAYER, INCREASES THE UTILITY OF THE ELECTROCATALYST BY 18%. THE RESULTS ARE CONSISTENT WITH THE PRESENCE OF POLYANILINE AS A CONDUCTIVE POLYMER IN THE REACTION LAYER REDUCING THE POLARIZATION RESISTANCE OF THE ELECTRODE IN COMPARISON WITH THAT OF A CORRESPONDING ELECTRODE CONTAINING NAFION. THUS, THE PRESENT RESULTS INDICATE THAT PEMFCS USING POLYANILINE-CONTAINING ELECTROCATALYSTS SHOULD GIVE SUPERIOR PERFORMANCE TO THOSE USING CATALYSTS CONTAINING TRADITIONALIONOMERS.

IN RECENT YEARS, UTILIZATION OF IONIC LIQUIDS (ILS) AS ELECTROLYTE ADDITIVES IS CONSIDERED AS A NEW TOPIC IN STUDIES OF FUEL CELLS AND BATTERIES. ILS ARE MOLTEN SALTS AT AMBIENT TEMPERATURE WHICH HAVE CONSIDERABLE POTENTIAL AS HIGH TEMPERATURE ELECTROLYTE MODIFIERS DUE TO THEIR UNIQUE PROPERTIES SUCH AS NON-VOLATILITY, HIGH IONIC CONDUCTIVITY, NON-FLAMMABILITY AND HIGH THERMAL STABILITY. IN THIS WORK, EFFECT OF ILS STRUCTURE ON THE PERFORMANCE OF DMFCS ANODE HAS BEEN STUDIED BY DIFFERENT ELECTROCHEMICAL METHODS SUCH AS CYCLIC VOLTAMMETRY (CV) AND ELECTROCHEMICAL IMPEDANCE SPECTROSCOPY (EIS). THE RESULTS SHOW THAT WITH INCREASING OF ALKYL CHAIN OF IL CATION, THE ELECTRO ACTIVITY OF CATALYST DECREASE IN METHANOL OXIDATION REACTION RELATED TO THE STRICE HINDRANCE OF IL CATION. A POSSIBLE EXPLANATION IS THAT WITH INCREASING THE NUMBER OF ALKYL CHAIN, BULK RESISTANCE INCREASED AND PROTON TRANSFER TO THE CATALYST SURFACE DECREASES AS WELL. FINALLY BY ANALYZING TEST RESULTS IT COULD BE CONCLUDED AT LOW TEMPERATURE ILS DOES NOT HAVE ANY PROMISING EFFECT ON THE CATALYST ACTIVITY AND THE ROLE OF ILS BECAME IMPORTANT AT HIGHER TEMPERATURES.

ENZYME BASED BIOELECTRONICS HAVE ATTRACTED INCREASING INTEREST IN RECENT YEARSBECAUSE OF THEIR APPLICATIONS ON BIOMEDICAL RESEARCH AND HEALTHCARE. THEY ALSO HAVE BROADAPPLICATIONS IN ENVIRONMENTAL MONITORING, AND AS THE POWER SOURCE FOR PORTABLE ELECTRONICDEVICES. IN THIS PAPER, THE TECHNOLOGY DEVELOPED FOR ENZYME BIOFUEL CELL HASBEEN DESCRIBED. THE PERFORMANCES OF ENZYMATIC BIOFUEL CELLS ARE SUMMARIZED. VARIOUS APPROACHES ON FURTHER DEVELOPMENT TO OVERCOME THE CURRENT CHALLENGES HAVE BEENDISCUSSED. THIS INNOVATIVE TECHNOLOGY WILL HAVE A MAJOR IMPACT AND BENEFIT MEDICALSCIENCE AND CLINICAL RESEARCH, HEALTHCARE MANAGEMENT, ENERGY PRODUCTION FROM RENEWABLE SOURCES.

USING FIRST PRINCIPLES CALCULATIONS, WE HAVE INVESTIGATED THE ADSORPTION OF CO MOLECULE ON BORON-NITRIDE NANOCAGE (BN)36 AS A ADSORBENT. OUR CALCULATIONS WERE PERFORMED AT THE B3LYP LEVEL OF DENSITY FUNCTIONAL THEORY ALONG WITH STANDARD SPLIT VALENCE BASIS SET 6-31G*. BY EXAMINING THE MOLECULAR ORBITALS AND BINDING ENERGIES OUR RESULTS INDICATE THAT B36N36 IS NOT SENSITIVE TO CARBON MONOXIDE AND JUST A PHYSICAL ADSORPTION OCCURS.

CARBON-SUPPORTED PD–CO ALLOY ELECTROCATALYST WERE SYNTHESIZED AND CHARACTERIZED FOR THE PURPOSE OF THE FUEL CELL CATHODE OXYGEN REDUCTION REACTION (ORR). AN IMPREGNATION METHOD WAS EMPLOYED FOR THE SYNTHESIS, IN WHICH EG WAS USED AS A REDUCING AGENT. THE SYNTHESIZED CATALYST WAS CHARACTERIZED IN TERMS OF CATALYTIC ACTIVITY BY ELECTROCHEMICAL MEASUREMENTS.SURFACE CYCLIC VOLTAMMETRY WAS USED TO CONFIRM THE FORMATION OF THE PD–CO ALLOY. IN ORDER TO IMPROVE ACTIVITY AND STABILITY, THE CATALYST WAS HEAT-TREATED IN THE TEMPERATURE OF 300OC. THE CATALYZED ORR KINETICS WERE ALSO STUDIED USING THE ROTATING DISK ELECTRODE (RDE) METHOD. ELECTROCATALYTIC ORR ACTIVITY WAS ALSO EXAMINED IN AN ACIDIC SOLUTION CONTAINING METHANOL. THE RESULTS SHOWED THAT THE SYNTHESIZED PD–CO/C CATALYST HAS METHANOL TOLERANT CAPABILITIES.

STAINLESS STEEL CAN BE USED AS INTERCONNECTS PLATE IN SOLID OXIDE FUEL CELLS (SOFC) FOR OPERATING TEMPERATURE OF 800OC OR BELOW. UNWANTED REACTIONS BETWEEN THE ALLOY AND OTHER SOFC COMPONENTS DECREASE THE EFFICIENCY OF THESE ENERGY CONVERTORS. ONE APPROACH TO IMPROVE INTERCONNECT PROPERTIES IS TO APPLY SURFACE COATING. IN THIS RESEARCH, AISI 430 FERRITIC STAINLESS STEEL WAS COATED IN A MN-BASE PACK MIXTURE BY PACK CEMENTATION METHOD. ELECTRICAL CONDUCTIVITY OF THE COATED COUPONS WAS MEASURED AS A FUNCTION OF TEMPERATURE BY OXIDIZING THE SAMPLES FROM ROOM TEMPERATURE TO 800OC. ALSO THE ELECTRICAL CONDUCTIVITY HAS BEEN STUDIED AS A FUNCTION OF OXIDATION TIME DURING ISOTHERMAL OXIDATION AT 800OC. RESULTS SHOWED THE INCREASE OF TEMPERATURE CAUSED TO THE DECREASE OF ELECTRICAL CONDUCTIVITY AND ALSO, THE COATING LAYER TRANSFORMED TO MANGANESE SPINELS DURING ISOTHERMAL OXIDATION. THE SPINEL COMPOSITIONS AMELIORATED THE ELECTRICAL CONDUCTIVITY ACTIVATION ENERGY OF COATED COUPONS (0.029 EV) COMPARED TO UNCOATED ONES (0.031 EV).

DURING NATURAL DISASTERS, THE LACK OF ADEQUATE BACKUP POWER FOR COMMUNICATIONS FACILITIES IS A CRITICAL PROBLEM THAT CAUSE NETWORK INTERRUPTIONS AND HAMPER RECOVERY EFFORTS. MANY EXISTING SITES HAVE A VALVE-REGULATED LEAD-ACID BATTERY BANK THAT PROVIDES UP TO FOUR HOURS OF BACKUP POWER CAPACITY IN THE EVENT OF A POWER OUTAGE. SOME LARGER AND/OR MORE CENTRALLY LOCATED SITES HAVE DIESEL GENERATORS FOR BACKUP POWER PURPOSES. HOWEVER, FOUR HOURS OF BACKUP CAN BE REGARDED AS A LIMITING FACTOR – LONGER RUNTIME IS REGULARLY REQUIRED IN FAST-GROWTH TELECOM NETWORKS WHERE THE ELECTRICITY GRID IS UNRELIABLE OR WHERE NATURAL DISASTERS ARE A REAL THREAT. DEPLOYMENT OF FUEL CELL SYSTEMS IS A PRACTICAL OPTION FOR TELECOM PROVIDERS NEEDING ROBUST, RELIABLE, EXTENDED-DURATION BACKUP POWER SUPPLY AT CELLULAR TELECOMMUNICATION SITES DURING EMERGENCIES. IN THIS PAPER A COMPARISON BETWEEN FUEL CELL AND LEAD-ACID BATTERY AS A BACKUP SYSTEM FOR TELECOM HAS BEEN ACCOMPLISHED. THE RESULTS SHOWN THAT FUEL CELL IS MUCH EFFICIENT.

ORGANIC-INORGANIC HYBRID MEMBRANES OF POLY (VINYL ALCOHOL) (PVA) AND MESOPOROUS SILICA CONTAINING SULFONIC ACID GROUPS ARE SYNTHESIZED WITH THE AIM OF INCREASING THE PROTON CONDUCTIVITY AND WATER RETENTION AS WELL AS IMPROVING THE THERMAL STABILITY. THESE HYBRID MEMBRANES WERE PREPARED VIA CO-CONDENSATION OF FUNCTIONALIZED NANOPOROUS SBA-15 (SBA-15-RSO3H) AS HYDROPHILIC INORGANIC MODIFIER, GLUTARALDEHYDE (GLA) AS CROSS-LINKING AGENT IN A PVA MATRIX. FOURIER TRANSFORM INFRARED SPECTROSCOPY (FT-IR) AND SCANNING ELECTRON MICROSCOPY (SEM) ARE USED TO CHARACTERIZE AND CONFIRM THE STRUCTURE OF PVA AND THE CROSSLINKED MEMBRANES. THE IMPEDANCE SPECTROSCOPY, WATER UPTAKE AND THERMAL STABILITY ARE INVESTIGATED TO CONFIRM THEIR APPLICABILITY IN FUEL CELLS. THIS WORK DEMONSTRATES THE PROMISING POTENTIAL OF NEW COMPOSITE MEMBRANES FOR THE DEVELOPMENT OF HIGH-PERFORMANCE AND HIGH-STABILITY PEM FUEL CELLS WITH IMPROVED PROTON CONDUCTIVITY.

RECENT STUDIES HAVE SHOWN THAT CARBON NANOTUBES CAN BE DISSOLVED IN CONDUCTIVE POLYMERS VIA FORMATION OF DONOR– ACCEPTOR COMPLEX. IN THIS WORK, WE HAVE PREPARED POLY O-AMINOPHENOL/MULTI-WALLED CARBON NANOTUBES (POAP/ MWNT) COMPOSITE BY ELECTROPOLYMERISATION OF AMINOPHENOL CONTAINING WELL-DISSOLVED MWNTS. NIO PARTICLES WERE ELECTRODEPOSITED ON THE COMPOSITE FILMS SUBSEQUENTLY. THE PRIMARY FOCUS OF THESE STUDIES IS TO COMPARE THE GLUCOSE OXIDATION ACTIVITY ON THE NI/ MWNT/POAP AND NI/POAP ELECTRODE.

IN ORDER TO REDUCE THE OXIDATION AND INCREASE THE FERRITIC STAINLESS STEELS ELECTRICAL CONDUCTIVITY, WHICH ARE USED AS INTERCONNECT MATERIAL IN SOLID OXIDE FUEL CELL, A LAYER OF PROTECTIVE/CONDUCTIVE COATING CAN BE DEPOSITED ON THE SURFACE. IN THIS STUDY COBALT HAS BEEN DEPOSITED ONTO THE SUBSTRATE AISI 430 FERRITIC STAINLESS STEEL BY PACK CEMENTATION TECHNIQUE. IN ORDER TO OPTIMIZE THE QUALITY OF THE FORMED COATING, THE EFFECTIVE FACTORS OF PACK CEMENTATION PROCESS WAS INVESTIGATED BY CHANGING THESE FACTORS, WHICH ARE SALT ACTIVATOR CONTENT IN THE PACK POWDER (0.5- 2%W.T.), DEPOSITION TEMPERATURE (700-800OC) AND DEPOSITION TIME (2-3H).THE ASCOATED SAMPLES WERE EXAMINED WITH SCANNING ELECTRON MICROSCOPY (SEM) ASSOCIATED WITH ENERGY DISPERSIVE SPECTROSCOPY (EDS). THE RESULTS SHOWED THAT EACH PARAMETER AFFECT THE THICKNESS OF COATING LAYER, COATING QUALITY AND THE INTEGRITY OF COATING. IT WAS REVEALED THAT THE FORMED COATING LAYER IN THE OPTIMIZED CONDITIONS INCLUDED COCR AND MNCO2O4 PHASES, THAT MNCO2O4 IS A SPINEL COMPOSITION AND HAS ACCEPTABLE ELECTRICAL CONDUCTIVITY IN OPERATING CONDITIONS OF SOFCS.

MICROBIAL FUEL CELLS (MFCS) HARVEST ELECTRIC ENERGY FROM ORGANIC MATTER BY MICROORGANISM ASSISTED OXIDATION OF ANY BIODEGRADABLE MATERIALS. IN THIS RESEARCH PALLADIUM WAS DEPOSITED ON INNER WALLS OF TIO2 NANOTUBES PREPARED THROUGH ANODIZING OF A TITANIUM ELECTRODE AND RESULTING TI/NANO-TIO2/PD ELECTRODE WAS EMPLOYED AS A CATHODE IN A DUAL-CHAMBERED MICROBIAL FUEL CELL WITH GRAPHITE ANODE. SOYBEAN MEAL AND RUMEN MIXED CULTURE BACTERIA WERE AS ORGANIC FEED AND BACTERIAL MEDIUM, RESPECTIVELY. CELL PERFORMANCE WAS INVESTIGATED BY POLARIZATION AND ELECTROCHEMICAL IMPEDANCE SPECTROSCOPY (EIS) METHODS. RESULTS SHOWED THAT DUE TO HIGH SURFACE AREA OF THE NANO-STRUCTURED CATHODE ALONG WITH ITS HIGHER ELECTRO-CATALYTIC ACTIVITY FOR OXYGEN REDUCTION REACTION IN THE CATHODIC PART OF THE MFC, THIS NOVEL EASY TO PREPARE ELECTRODE ALONG WITH THE INCORPORATED RUMEN MIXED CULTURE BACTERIA AND SOYBEAN FEED CAN BE EFFECTIVELY USED TO EXTRACT ELECTRICAL ENERGY FROM LOW COST BOTANIC MATERIALS.

THE ELECTROOXIDATION OF ETHYLENE GLYCOL (EG) ON CPE/POLY (N,N–DIMETHYL ANILINE)-(SDS) (CPE/PDMAN-SDS) WITH DIFFERENT PROPORTIONS OF NI (II) AND CO (II) IN 1 M NAOH WAS STUDIED BY CYCLIC VOLTAMMETRY. THE RESULTS SHOW THAT FORMED LAYERS AT THE SURFACE OF THE ELECTRODES BEHAVE AS AN EFFICIENT ELECTROCATALYST FOR THE OXIDATION OF EG IN ALKALINE MEDIUM VIA THE NI (III) AND CO (III) SPECIES. THESE MODIFIED ELECTRODES EXHIBIT HIGH ELECTROCATALYTIC ACTIVITY AND STABILITY IN ALKALINE SOLUTION, SHOWING OXIDATION PEAKS AT LOW POTENTIALS WITH HIGH CURRENT DENSITIES. THE EFFECTS OF VARIOUS PARAMETERS SUCH AS POTENTIAL SCAN RATES, EG CONCENTRATION AND THE SUPPORTING ELECTROLYTES ON THE ELECTROOXIDATION OF EG ARE ALSO INVESTIGATED.

SPINEL COATINGS THAT CONTAIN COBALT ARE HOPEFUL CANDIDATES FOR SOLID OXIDE FUEL CELL (SOFC) INTERCONNECT APPLICATIONS BECAUSE OF THEIR HIGH CONDUCTIVITY. THE PURPOSE OF THIS WORK WAS TO INVESTIGATE THE ELECTRICAL CONDUCTIVITY OF AISI 430 STAINLESS STEEL WHICH WAS COATED IN A CO-BASE PACK MIXTURE BY PACK CEMENTATION METHOD. ELECTRICAL CONDUCTIVITY OF THE COATED SUBSTRATES WAS TESTED AS A FUNCTION OF TEMPERATURE BY ANNEALING THE SAMPLES FROM ROOM TEMPERATURE TO 800OC. ALSO ELECTRICAL CONDUCTIVITY HAS BEEN INVESTIGATED AS A FUNCTION OF OXIDATION TIME DURING ISOTHERMAL OXIDATION AT 800OC. RESULTS SHOWED THE INCREASE OF TEMPERATURE CAUSED TO THE DECREASE OF ELECTRICAL CONDUCTIVITY .RESULT OF X-RAY DIFFRACTION PATTERN EXHIBITED, THAT THE COATING LAYER TRANSFORMED TO MNCO2O4 AND COCR2O4 SPINELS DURING ANNEALING IN ISOTHERMAL OXIDATION. THESE SPINELS IMPROVED ELECTRICAL CONDUCTIVITY OF COATED SUBSTRATES (103 S.CM-1) COMPARED TO UNCOATED SUBSTRATES (27.7 S.CM-1) AFTER 200 H OXIDATION AT 800OC.

THIS PAPER SHOWS AN EXHAUSTIVE PRESENTATION AND COMPLEMENTARY DISCUSSIONS ON VARIOUS ASPECTS OF WORKS DONE RECENTLY ON THE DEVELOPMENTS OF COMPOSITE MEMBRANES FOR POLYMER ELECTROLYTE FUEL CELL (PEFC) APPLICATIONS. THE ELECTROPOLYMERISATION OF POLYANILINE/AG (PANI/AG) AND POLY (O_METHYLANILINE)/AG (POMEANI)/AG NANOCOMPOSITES WERE PREPARED BY INSITU OXIDATIVE POLYMERIZATION OF ANILINE MONOMER IN THE PRESENCE OF DIFFERENT CONCENTRATIONS OF AG NANOPARTICLES. THE FORMATION OF PANI/AG AND ITS DERIVATIVE NANOCOMPOSITES WAS CHARACTERIZED BY FTIR AND UV–VIS SPECTROSCOPY. CYCLIC VOLTAMMETRY (CV) AND ELECTROCHEMICAL IMPEDANCE SPECTROSCOPY (EIS) WERE USED TO INVESTIGATE THE ELECTROCHEMICAL PROPERTIES POLYANILINE/AG AND POLY(O_METYLANILINE)/AG .CV AND EIS RESULTS SHOW THAT THE PANI/AG FILM EXHIBITS CONSIDERABLY HIGHER ELECTROACTIVITY COMPARED WITH ITS DERIVATIVE. THE RESEARCH INTEREST IS TO IMPLEMENT THE CONDUCTING POLYMERS IN FUEL CELL TECHNOLOGY, AS MEMBRANE ELECTROLYTE FUEL CELL COMPONENTS OR CONDUCTING SUPPORTS FOR NOBLE METAL DEPOSITION.

POLY (ISONICOTINIC ACID) (PINA) WAS FORMED BY SUCCESSIVE CYCLIC VOLTAMMETRY IN MONOMER SOLUTION IN THE PRESENCE OF SODIUM DODECYL SULFATE (SDS) ON THE SURFACE OF CARBON PASTE ELECTRODE. NI (II) AND CO (II) IONS WERE INCORPORATED INTO THE ELECTRODE BY IMMERSION OF THE POLYMERIC MODIFIED ELECTRODES IN NI (II) AND CO (II) IONS SOLUTION WITH DIFFERENT PROPORTIONS. AFTER THE PREPARATION OF MODIFIED ELECTRODES, ELECTROCHEMICAL BEHAVIOR OF THEM WAS DISCUSSED BY CYCLIC VOLTAMMETRIC EXPERIMENTS. THEN THE ELECTROCATALYTIC OXIDATION OF METHANOL AT THE SURFACE OF MODIFIED ELECTRODES WAS STUDIED IN 1 M NAOH SOLUTION. THE RESULTS SHOW THAT THE ELECTROOXIDATION OF METHANOL WAS FOUND TO BE MORE EFFICIENT ON CPE/PINA(SDS)/NI80CO20 THAN ON CPE/PINA(SDS)/NI AND CPE/PINA(SDS)/NI50CO50.

THE FORMED OXIDE LAYER ON INTERCONNECTS IN SOLID OXIDE FUEL CELLS (SOFCS) DECREASE THE ELECTRICAL CONDUCTIVITY AND THEREFORE ENERGY LOSSES CAN BE OCCURRED. THE ELECTRICAL CONDUCTIVITY OF FERRITIC STAINLESS STEELS CAN BE IMPROVED BY COATING IT WITH A PROTECTIVE/CONDUCTIVE LAYER. IN THIS STUDY AISI 430 FERRITIC STAINLESS STEEL WAS COATED IN A COBALT-BASE PACK MIXTURE BY PACK CEMENTATION METHOD. THE EFFECT OF OXIDE SCALE THICKNESS ON THE AREA SPECIFIC RESISTANCE (ASR) WAS EVALUATED BY APPLYING ISOTHERMAL OXIDATION. THIS EFFECT WAS ALSO INVESTIGATED IN DIFFERENT TEMPERATURES (400-700OC). SPINELS FORMING (MNCO2O4, COCR2O4, COFE2O4 AND CO3O4) DURING ANNEALING AMELIORATED OXIDATION RESISTANCE AND ELECTRICAL CONDUCTIVITY. RESULTS SHOWED THAT THE INCREASE OF ISOTHERMAL OXIDATION TIME AND INCREASE OF TEMPERATURE, INCREASE THE OXIDE THICKNESS AND IT CAUSE TO THE HIGHER VALUES OF ASR.

THE ELECTROCHEMICAL TREATMENT OF CANCER (ECHT) CONSISTS IN THE PASSAGE OF A DIRECT ELECTRIC CURRENT THROUGH TWO OR MORE ELECTRODES INSERTED LOCALLY IN THE TUMOR TISSUE. THE EXTREME PH CHANGES INDUCED HAVE BEEN PROPOSED AS THE MAIN TUMOR DESTRUCTION MECHANISM. THE STUDIES PRESENTED IN THIS RESEARCH HAVE GIVEN A STRONG INDICATION OF THE DESTRUCTION MECHANISM INVOLVED IN ECHT. MATHEMATICAL MODELS, DESCRIBING THE PHYSICOCHEMICAL REACTION AND TRANSPORT PROCESSES OF SPECIES DISSOLVED IN TISSUE SURROUNDING PLATINUM ANODES AND CATHODES, DURING ECHT, ARE DEVELOPED AND VISUALIZED WITH COMSOL MULTIPHYSICS SOFTWARE IN THIS STUDY. THE CONSIDERED ELECTROCHEMICAL REACTIONS ARE OXYGEN AND CHLORINE EVOLUTION, AT THE ANODE, AND HYDROGEN EVOLUTION AT THE CATHODE. CONCENTRATION PROFILES OF SUBSTANCES DISSOLVED IN TISSUE, AND THE POTENTIAL PROFILE WITHIN THE TISSUE ITSELF, ARE SIMULATED AS FUNCTIONS OF TIME. MODELING WORK OF THE ANODE PROCESSES HAS EXPLAINED THE ROLE OF CHLORINE IN THE UNDERLYING DESTRUCTION MECHANISM BEHIND ECHT. IT IS FOUND THAT THE REACTIONS OF CHLORINE WITH TISSUE PLAY IMPORTANT ROLES AS GENERATORS OF HYDROGEN IONS. THE CONTRIBUTION OF THESE REACTIONS TO THE ACIDIFICATION OF TISSUE, SURROUNDING THE ANODE, IS STRONGLY DEPENDENT ON THE APPLIED CURRENT DENSITY AND INCREASES WITH DECREASING CURRENT DENSITY.

HYDROGEN IS AN IDEAL FUEL BECAUSE OF ITS ZERO OR LOW POLLUTANT EMISSION DURING COMBUSTION. FOR THE UTILIZATION FOR HYDROGEN, HYDROGEN STORAGE TECHNOLOGY IS NECESSARY, IN WHICH LIGHT, ENVIRONMENTALLY FRIENDLY AND CHEAP MATERIALS ARE REQUIRED TO BE USED SPECIALLY IN THE FUEL CELL VEHICLES. THERE ARE DIFFERENT TECHNIQUES TO STORE HYDROGEN. ALL THOSE TECHNIQUES HAVE TO MEET THE PROVISIONAL DEPARTMENT OF ENERGY OF THE UNITED STATES (DOE) CRITERION. THE DOE HAS ESTABLISHED DIFFERENT TARGETS FOR ON-BOARD HYDROGEN STORAGE SYSTEMS, INCLUDING THE MINIMUM “GRAVIMETRIC” AND “VOLUMETRIC” CAPACITY AND THE REVERSIBILITY OF CHARGING/DISCHARGING PROCESSES. SINCE 1997, WHEN DILLON ET AL. REPORTED THAT THE CARBON NANOTUBES (CNTS) CAN STORE HYDROGEN, NUMEROUS EXPERIMENTAL AND THEORETICAL WORKS HAVE BEEN PERFORMED IN ORDER TO INVESTIGATE HYDROGEN ADSORPTION IN CNTS AND TO IMPROVE THE STORAGE CAPACITY OF THE TUBES BY DOPING THEM. THE CARBON NANOTUBES SEEM TO BE AN ULTIMATE MATERIAL FOR HYDROGEN STORAGE, DUE TO THEIR CHEMICAL STABILITY, LARGE SURFACE AREA, HOLLOWNESS, AND LIGHT MASS. PHYSICAL ADSORPTION IS GENERALLY ACCOUNTED FOR THE WAY THAT HYDROGEN IS STORED IN CARBON MATERIALS AND MOST STUDIES CONCERNING HYDROGEN STORAGE HAVE BEEN CARRIED OUT AT HIGH PRESSURES (1-16MPA) AND LOW TEMPERATURES (80-133K) IN ORDER TO STORE MOLECULAR HYDROGEN BY PHYSISORPTION. HYDROGEN ATOMS CAN BE STORED DOMINANTLY THROUGH THE TUBE WALL BY BREAKING C-C MID BOND, WHILE PRESERVING THE WALL STABILITY OF A NANOTUBE AFTER COMPLETE HYDROGEN INSERTION, RATHER THAN BY THE CAPILLARITY EFFECT THROUGH ENDS OF NANOTUBES. IN THE HYDROGEN EXTRACTION PROCESSES, HYDROGEN MOLECULES IN THE CAPILLARY OF NANOTUBES FIRST DISSOCIATES AND ADSORBS ON TO THE INNER WALL AND IS FURTHER EXTRACTED TO THE OUTER WALL BY THE FLIP-OUT MECHANISM. HYDROGEN STORAGE CAPACITY OF CARBON NANOTUBES AND CARBON NANO FIBERS IS DETERMINED BY PHYSICAL PROPERTIES SUCH AS PORE GEOMETRY, SURFACE AREA, AND APPEARANCE OF GRAPHITE SHEETS. IN THIS PAPER WE DISCUSS ABOUT THE STRUCTURE OF CARBON NANO FIBERS AND CARBON NANOTUBES, AND WE ALSO DISCUSS ABOUT THE HYDROGEN STORAGE ON THESE CARBON NANOMATERIAL’S WHICH USED IN THE ON-BOARD STORAGE OF HYDROGEN IN THE FUEL CELL VEHICLES.

IN THIS WORK, FOR THE FIRST TIME AN AQUEOUS SOLUTION OF TRITON X-100 (TX-100) NONIONIC SURFACTANT IS USED AS AN ADDITIVE FOR ELECTROPOLYMERIZATION OF O-TOLUIDINE (OT) ONTO MULTI-WALLED CARBON NANOTUBE PASTE ELECTRODE (CNTPE), WHICH IS INVESTIGATED AS A NOVEL MATRIX FOR DISPERSION OF CATALYSTS. THE AS-PREPARED SUBSTRATE IS USED AS POROUS MATRIX FOR DISPERSION OF TRANSITION METAL IONS OF NI(II) TO POT/TX-100 FILM BY IMMERSING THE MODIFIED ELECTRODE IN A 0.1 M NICKEL SULFATE SOLUTION. THE ELECTROCHEMICAL CHARACTERIZATION OF THIS MODIFIED ELECTRODE EXHIBITS REDOX BEHAVIOR OF NI(III)/NI(II) COUPLE. IT HAS BEEN SHOWN THAT POT/TX- 100 AT THE SURFACE OF CNTPE IMPROVES CATALYTIC EFFICIENCY OF THE DISPERSED NICKEL IONS TOWARD METHANOL OXIDATION. THEN, USING A CHRONOAMPEROMETRIC METHOD, THE CATALYTIC RATE CONSTANT, K, FOR METHANOL OXIDATION IS FOUND TO BE 7.40 ×104 CM3 MOL-1 S-1. AT THE END OF THIS WORK, LONG-TERM STABILITY OF THE MODIFIED ELECTRODE HAS BEEN INVESTIGATED.

MULTI-WALLED CARBON NANOTUBE -SUPPORTED PT-DOPED CEO2 NANOPARTICLES WERE SYNTHESIZED IN AN ELECTRODEPOSITION BATH CONTAINING CONSTANT CONCENTRATIONS OF H2PTCL6 AND DIFFERENT CONCENTRATIONS OF CEO2. THE ELECTROCATALYTIC ACTIVITIES OF CATALYSTS WERE STUDIED IN 0.5 M H2SO4 FOR OXYGEN REDUCTION REACTION FOR PROTON EXCHANGE MEMBRANE FUEL CELLS (PEMFCS) BY CYCLIC VOLTAMMETRY, ROTATING DISK ELECTRODE VOLTAMMETRY, CHRONOPOTENTIOMETRY AND CHRONOAMPEROMETRY.THE CEO2 CONTAINING ELECTROCATALYSTS SHOW IMPROVED ELECTROCHEMICAL PERFORMANCES. THE OPTIMUM RESULTS ARE IN STATES THAT CEO2 CONCENTRATION IN ELECTRODEPOSITION BATH IS 10 MM. XRD ANALYZE GIVE ADDITIONAL INFORMATION ON THE MORPHOLOGICAL STRUCTURE OF ELECTROCATALYSTS.

PTSN-CEO2 NANOPARTICLES HAVE BEEN PREPARED BY A IMPREGNATION METHOD. XRD SHOWS THE FORMATION OF PTSN ALLOY WITH AVERAGE SIZES OF 4.5 NM. THE PTSN-CEO2 NANOPARTICLES SHOW ENHANCED ELECTROCATALYTIC ACTIVITY FOR THE ELECTROOXIDATION OF METHANOL COMPARED WITH THAT AT PT NANOCLUSTERS. THE ONSET POTENTIAL FOR THE OXIDATION OF METHANOL FOR PTSN-CEO2 NANPARTICLES, WHICH IS MORE NEGATIVE THAN THAT OF PT NANOCLUSTERS. PEAK CURRENT DENSITY OF PTSN-CEO2 NANOPARTICLES IS HIGHER THAN THAT OF PT NANOCLUSTERS.

PT-NI NANOPARTICLES SUPPORTED ON CARBON-CERAMIC ELECTRODE (PT-NI/CCE) ARE PREPARED BY AN ELECTRODEPOSITED PROCESS. THE CATALYSTS ARE CHARACTERIZED BY SCANNING ELECTRON MICROSCOPY, ENERGY-DISPERSIVE X-RAY SPECTROSCOPY (EDX) AND CYCLIC VOLTAMMETRY. THE RESULTS SHOW THAT THE PT-NI NANOPARTICLES DISPERSED UNIFORMLY ON CARBON-CERAMIC ELECTRODE. THE PT-NI/CCE CATALYSTS HAVE HIGHER ELECTROCATALYTIC ACTIVITY FOR FORMIC ACID OXIDATION THAN A COMPARATIVE PT/CCE AND SHOW GREAT POTENTIAL AS LESS EXPENSIVE ELECTROCATALYST. THE EFFECT OF SOME EXPERIMENTAL FACTORS WAS STUDIED AND OPTIMUM CONDITIONS WERE SUGGESTED. FINALLY, THE LONG-TERM STABILITY OF THE MODIFIED ELECTRODE HAS ALSO BEEN INVESTIGATED. THESE RESULTS INDICATE THAT THE SYSTEM STUDIED IN THE PRESENT WORK IS THE MOST PROMISING SYSTEM FOR USE IN DIRECT FORMIC ACID FUEL CELLS (DFAFCS).

IN ORDER TO INVESTIGATE THE OUTPUT CHARACTERISTIC OF A FUEL CELL BASED ON THE ELECTRICAL EMPIRICAL MODEL, A 40A/0.8KW/100V, HIGH PERFORMANCE DYNAMIC FUEL CELL LOAD SYSTEM WITH TOTAL PROTECTION CIRCUITS IS PRESENTED USING WITH PARALLEL POWER MOSFETS ,ANALOG AND DIGITAL ISOLATION TECHNIQUE. THIS EFFICIENT DYNAMIC LOAD UTILIZES CURRENT AND VOLTAGE FEEDBACK TO REALIZE PROTECTIONS. THE SAFETY IS INCREASED DUE TO EMPLOYING BOTH CONTROL COMMANDS AND FEEDBACK SIGNALS. THIS PROGRAMMABLE DYNAMIC LOAD WILL BE VERY USEFUL TO OPTIMIZE THE FUEL CELL DESIGN, IMPROVE THE OPERATION PERFORMANCE, AND DEVELOP THE REAL-TIME CONTROL SYSTEM OF FUEL CELLS. A GOOD MATCH IS FOUND BETWEEN SIMULATION RESULTS AND EXPERIMENTAL DATA. THE ELECTRONIC LOAD REMOTELY PROGRAMMED VIA AN RS-232 SERIAL PORT.

NANO-COMPOSITE POLYMER MEMBRANES BASED ON POLY(VINYL ALCOHOL)/ TITANIUM OXIDE (PVA/TIO2) WERE PREPARED BY ELECTROSPINNING TECHNIQUE. ELECTROSPINNING IS AN EFFICIENT METHOD FOR FABRICATING POLYMER MEMBRANES WHICH ARE MADE UP OF ULTRAFINE FIBERS WITH DIAMETERS IN THE RANGE OF FEW NANOMETERS TO SUB- MICROMETERS[1]. GLUTARALDEHYDE (GA) WAS USED AS A CROSS-LINKING AGENT IN ORDER TO IMPROVE CHEMICAL, THERMAL AND DIMENTIONAL STABILITIES.THE PROPERTIES OF CROSSLINKED ELECTROSPUN MEMBRANES WERE CHARACTERIZED BY SCANNING ELECTRON MICROSCOPY (SEM), CALCULATION OF WATER UPTAKE (WU) AND X-RAY DIFFRACTION (XRD). THE CHANGES OF IONIC CONDUCTIVITIES OF MEMBRANES CROSSLINKED WITH DIFFERENT AMOUNTS OF GA WERE INSPECTED BY ELECTROCHEMICAL IMPEDANCE SPECTROSCOPY (EIS) METHOD, WHEN THE MEMBRANES WERE PLACED IN VARIOUS ALKALINE SOLUTIONS FOR 24 H. ACCORDING TO OBTAINED RESULTS, THESE NANOFIBROUS MEMBRANES ARE PROMISING ANION EXCHANGE POLYMER ELECTROLYTES FOR DIRECT ETHANOL FUEL CELL (DEFC) APPLICATIONS.

THIS PAPER INVESTIGATES THE EFFECTS OF PRESSURE, FILLER CONTENTS AND TYPE OF FILLERS ON THROUGH-PLANE AND IN-PLANE ELECTRICAL CONDUCTIVITY, MECHANICAL PROPERTIES (FLEXURAL STRENGTH AND HARDNESS), DENSITY, POROSITY AND WATER ABSORPTION OF PHENOLIC RESIN/GRAPHITE COMPOSITE. THIS COMPOSITE IS A CANDIDATE FOR EMPLOYING IN BIPOLAR PLATE. THE COMPOSITE WAS MANUFACTURED BY HOT COMPACTION METHOD. IN THIS RESEARCH TWO PRESSURE 15 AND 740 BARS HAVE BEEN APPLIED IN 20, 30, 40, 50, 60, 70 AND 80 %WT GRAPHITE CONTENTS AS FILLER. THE CHARACTERIZATION WAS ALSO CONDUCTED BY AN OPTIC MICROSCOPE, A STEREOSCOPE (FOR POROSITY CHARACTERIZATION) AND SEM (FOR CHARACTERIZING FRACTURE MECHANISM). THE RESULTS SHOWED THAT THE PRESSURE CONSIDERABLY AFFECT ON ALL OF PROPERTIES AND CAN DRAMATICALLY CHANGE THE POROSITY PERCENTAGE OF COMPOSITE. THE MECHANICAL PROPERTIES WERE MAXIMIZED IN ABOUT 40%WT. IT WAS FOUND THAT THE SINGLE REINFORCING FILLER CONSTITUENT COMPOSITE PLATES DO NOT PROVIDE THE REQUISITE PROPERTIES FOR THE PURPOSE OF BEING USED AS THE BIPOLAR PLATE. HENCE THE PHENOLIC RESIN/GRAPHITE COMPOSITE PLATES WERE MODIFIED BY NANOSHEET EXPANDED GRAPHITE AND CARBON FIBER (IN ORDER TO IMPROVE ELECTRICAL CONDUCTIVITY AND MECHANICAL STRENGTH RESPECTIVELY). THESE SAMPLES WERE FABRICATED IN 5, 10 AND 20%WT OF EXPANDED GRAPHITE AND 5%WT OF CARBON FIBER. IN THE OPTIMUM COMPOSITION (P/40%G/5%EG/5%CF), THE IN-PLANE ELECTRICAL CONDUCTIVITY, THROUGH-PLANE ELECTRICAL CONDUCTIVITY AND FLEXURAL STRENGTH OF COMPOSITE BIPOLAR PLATES WERE PRODUCED WITH OF 1518 S/CM, 76 S/CM AND 84 MPA RESPECTIVELY THAT PERFORM DOE GUIDELINE. IN THIS WORK CONTACT RESISTANCE BETWEEN BIPOLAR PLATE AND GDL (GAS DIFFUSION LAYER) WAS DETERMINED BY CHANGING PRESSURE.

HYDROGEN IS CONSIDERED AS A POTENTIAL FUEL FOR THE FUTURE. HYDROGEN STORAGE IS THE KEY TECHNOLOGY TOWARDS THE HYDROGEN SOCIETY. ONBOARD STORAGE IS THE CRITICAL ISSUE WITH REGARD TO HYDROGEN’S UTILITY AS AN ENERGY CARRIER FOR ANY MODE OF TRANSPORTATION ON LAND, SEA OR AIR. NOWADAYS WE NEED FOR THE ON-BOARD FUEL SYSTEM STORAGE SINCE HYDROGEN EXHIBITS A RATHER LOW VOLUMETRIC ENERGY DENSITY (REGARDLESS WHETHER IT IS STORED AS A LIQUID AT CRYOGENIC TEMPERATURES OR AS A COMPRESSED GAS). IN MOST CONVENTIONAL ANALYSIS FOR DESIGN OF HYDROGEN STORAGE SYSTEMS THE GRAVIMETRIC AND VOLUMETRIC STORAGE DENSITIES ARE USED. THE STUDIES WERE PERFORMED ON PROCESSES AIMED AT REACHING THE VOLUMETRIC CAPACITIES AND GRAVIMETRIC STORAGE DENSITIES RECOMMENDED BY THE US DOE, I.E., 45 KG/M3 AND 6 WEIGHT PERCENT, FOR THE YEAR 2010. COMPRESSED HYDROGEN FUEL TANK OPERATES UNDER HIGH (5000-10000PSI) PRESSURE, SO THESE TANKS SHOULD HAVE SPECIAL STRUCTURE TO BE SUITABLE FOR FUEL CELL VEHICLES. THIS PAPER EXPLAINS THE CURRENT STATUS AND CHALLENGES OF CONVENTIONAL TECHNOLOGIES FOR THE HYDROGEN STORAGE BY TANKS AND ALSO DISCUSSES ABOUT THE HYDROGEN TANKS STRUCTURE.

THE ELECTRO-OXIDATION OF GLUCOSE ON NI/POLYMER NANOCOMPOSITE) POLY ORTHO AMINOPHENOL +CARBON NANOTUBE (MODIFIED GLASSY CARBON ELECTRODE IN A 1M NAOH SOLUTION AT DIFFERENT CONCENTRATION OF GLUCOSE WAS STUDIED BY THE METHOD OF ACIMPEDANCE SPECTROSCOPY .IN LOW CONCENTRATION OF GLUCOSE )<5MM (TWO SEMICIRCLES IN THE FIRST QUADRANT OF A NYQUIST DIAGRAM WERE OBSERVED CORRESPONDING TO CHARGE TRANSFER RESISTANCE AND ADSORPTION OF INTERMEDIATES .THE IMPEDANCE DATA IN HIGH CONCENTRATION OF GLUCOSE SHOW DIFFERENT BEHAVIOR AT DIFFERENT APPLIED ANODIC POTENTIAL .THE INFLUENCE OF THE ELECTRODE POTENTIAL ON IMPEDANCE PATTERN IN HIGH CONCENTRATION OF GLUCOSE IS STUDIED AND A MATHEMATICAL MODELWAS PUT FORWARD TO QUANTITATIVE ACCOUNT FOR THE IMPEDANCE BEHAVIOR OF GLUCOSE OXIDATION .AT POTENTIALS HIGHER THAN 0.545 V/AG–AGCL, A PSEUDO INDUCTIVE BEHAVIOR IS OBSERVED BUT AT HIGHER THAN 0.35 V/AG– AGCL, IMPEDANCE PATTERNS TERMINATE IN THE SECOND AND THIRD QUADRANTS .THE CONDITIONS REQUIRED FOR THIS BEHAVIOR ARE DELINEATED WITH THE USE OF THE IMPEDANCE MODEL.

MOLECULAR DYNAMICS (MD) SIMULATION TECHNIQUE WAS USED TO INVESTIGATE THE EFFECT OF DEGREE OF SULFONATION (DS) ON THE STRUCTURAL AND TRANSPORT PROPERTIES OF SULFONATED POLY (ETHER ETHER KETONE) (SPEEK) MEMBRANE AT DIFFERENT TEMPERATURES. SIMULATIONS WERE PERFORMED FOR THE CELL CONTAINING SPEEK MEMBRANE, HYDRONIUM IONS AND WATER MOLECULES. BY ANALYZING THE PAIR CORRELATION FUNCTION (PCF), IT WAS FOUND THAT WITH INCREASING THE DEGREE OF SULFONATION, THE DISTANCE BETWEEN SULFONIC ACID GROUPS AND THE DISTANCE BETWEEN SULFONIC ACID GROUPS AND HYDRONIUM IONS ARE DECREASED. FURTHERMORE, THE PCF ANALYSIS OF WATER-HYDRONIUM PAIR SHOWS THAT WATER MOLECULES AND HYDRONIUM IONS ARE LOCATED AT FAR DISTANCES FROM EACH OTHER. HOWEVER, THE DIFFUSION COEFFICIENT AND IONIC CONDUCTIVITY OF HYDRONIUM IONS INCREASE DUE TO THE GREATER NUMBER OF THE HYDRONIUM IONS AT HIGH DS CONDITIONS. SIMULATED IONIC CONDUCTIVITIES FOLLOW EXPERIMENTAL DATA QUALITATIVELY, BUT DUE TO SIMULATION CONDITIONS, SOME DIFFERENCES BETWEEN SIMULATION RESULTS AND EXPERIMENT ARE OBSERVED.

BIMETALLIC PLATINUM–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

IN THE PRESENT WORK, THE SATURATION INFLUENCE OF THE CATHODE CATALYST LAYER (CCL) OF PROTON EXCHANGE MEMBRANE FUEL CELL (PEMFC) ON CELL PERFORMANCE IS STUDIED. FOR THIS MEAN, A STEADY- STATE, MACRO-HOMOGENEOUS CATALYST LAYER (CL) MODEL IS USED TO INVESTIGATE THE EFFECT OF VARIOUS SATURATION CONDITIONS. THIS MODEL SOLVES THE GOVERNING EQUATIONS FOR THE OXYGEN DIFFUSION, THE RATE OF ELECTROCHEMICAL REACTIONS, AND TRANSPORTS OF PROTONS AND ELECTRONS THROUGH THE MEMBRANE AND SOLID PHASES, RESPECTIVELY. THE CATHODE CL CONTAINS: MEMBRANE, SOLID, CATALYST PARTICLES AND VOID SPACES. THE VOID SPACES ARE ASSUMED TO BE VARIOUS SATURATION OF LIQUID WATER (100, 70 AND 50%), THEREFORE, THE OXYGEN SPECIES MUST DIFFUSE IN LIQUID- AND VAPOR-WATER AND IONOMER PHASE TO REACH TO THE ACTIVE SITES. SIMULATION RESULTS SHOW THAT CATHODE CL SATURATION PLAYS VERY IMPORTANT ROLE ON THE PEMFC PERFORMANCE. IMPROVED PERFORMANCES ARE ACHIEVED AT SATURATION LEVELS OF CCL 50 TO 70%, AS OXYGEN DIFFUSES IN VAPOR MUCH EASIER THAN IN FULLY FLOODED CCL.

THIS PAPER DEALS A NOVEL STRATEGY DEVELOPED FOR OPTIMIZING THE POWER FLOW IN A FUEL CELL HYBRID ELECTRIC VEHICLE (FCHEV) STRUCTURE. THIS METHOD IMPLEMENTED AN ON-LINE POWER MANAGEMENT BY A FUZZY CONTROLLER BETWEEN DUAL POWER SOURCES THAT CONSIST OF A BATTERY BANK AND A FUEL CELL (FC). THIS STRUCTURE INCLUDED BATTERY AND FUEL CELL AND ITS POWER TRAIN SYSTEM INCLUDE AN ELECTRIC MOTOR (EM). THE PROPOSED METHOD INVOLVES AN ADVANCE SUPERVISORY CONTROLLER IN THE FIRST LAYER WHICH INCLUDED ALL OF POSSIBLE OPERATION MODES. WITH REGARDS THE OPERATION MODE, THE UPPER LAYER MAKE DECISION TO CHOOSE THE SWITCHING CHAIN ROLES AND RESPECT CONTROLLER IN THE SECOND LAYER. FINALLY IN THE THIRD LAYER, THERE ARE LOCAL CONTROLLER TO REGULATE THE SET POINTS OF EACH SUBSYSTEMS TO REACH THE BEST PERFORMANCE AND ACCEPTABLE OPERATION INDEXES. SIMULATION RESULTS OF A TEST SYSTEM ILLUSTRATE IMPROVEMENT IN THE OPERATION EFFICIENCY OF THE HYBRID POWER SYSTEM AND THE BATTERY STATE OF CHARGE HAS BEEN MAINTAINED AT A REASONABLE LEVEL.

IN THIS WORK, THE ELECTROCATALYTIC OXIDATION OF METHANOL IN ALKALINE MEDIUM AT NICKEL MODIFIED IONIC LIQUID/CARBON PASTE ELECTRODE (NI/IL/CPE) WAS INVESTIGATED. THE IONIC LIQUID, 1-BUTYL-3-METHYLIMIDAZOLIUM BIS (TRIFLUOROMETHYLSULFONYL)IMIDE, WAS INCORPORATED IN THE ELECTRODE AS A BINDER. NI (II) IONS WERE INCORPORATED INTO THE ELECTRODE BY IMMERSION OF THIS ELECTRODE IN 1 M NICKEL SULPHATE SOLUTION. CYCLIC VOLTAMMETRY AND CHRONOAMPEROMETRY TECHNIQUES WERE USED FOR THE ELECTROCHEMICAL STUDY OF THIS MODIFIED ELECTRODE IN THE ABSENCE AND PRESENCE OF METHANOL. RESULTS SHOW THAT THIS ELECTRODE EXHIBITS A SUPERIOR ELECTROCATALYTIC ACTIVITY TOWARDS THE OXIDATION OF METHANOL AND A HIGH DENSITY ELECTROCATALYTIC CURRENT WAS ACHIEVED. THE RATE CONSTANT FOR THE CHEMICAL REACTION BETWEEN THE METHANOL AND REDOX SITES OF ELECTRODE WAS CALCULATED. THIS NEW PROPOSED ELECTRODE IS SIMPLE AND EFFICIENT ENOUGH AND IT CAN BE WIDELY USED AS ANODE IN DIRECT METHANOL FUEL CELL.

AN ELECTROLESS TECHNIQUE WAS DEVELOPED TO COAT NICKEL ON GRAPHITE WITH HIGH NICKEL DEPOSITION RATE AND BATH STABILITY. THE GRAPHITE WERE PRE-TREATED BY PUTTING THE ELECTRODES IN COLORIDE STANNOUS AND PALLADIUM COLORIDE BATH. AS IT PUBLISHED IN LITERATURE ELECTROLESS NICKEL (EN) DEPOSITION BATH IS KNOWN TO HAVE A MAJOR PROBLEM OF SUDDEN BATH DECOMPOSITION, WHICH RESULTS IN AN INCREASE IN THE OPERATING COST AND THE GENERATION OF ENVIRONMENTALLY HAZARDOUS WASTE. BATH STABILIZERS ARE NORMALLY ADDED TO EXTEND ITS LIFE. IN THIS PAPER, THE EFFECTS OF SOME ELECTROLESS NICKEL BATH STABILIZERS, POTASSIUM SODIUM TARTARAT TETRAHYDRATE, ACETATE PLUMB AND SODIUMDODECYL SULFATE WERE INVESTIGATED. IT WAS OBSERVED THAT THE STABILIZERS HAVE A MAJOR EFFECT ON THE EN DEPOSITS. IT IS ALSO SHOWN THAT THE ADDITION OF SURFACTANT HAS AN EFFECT ON THE NANO-GRAIN SIZE OF THE EN DEPOSIT. SCANNING ELECTRON MICROSCOPY (SEM) IMAGES, XRD PATTERN OF THE COMPOSITES ALL CONFIRM THE DEPOSITION OF NICKEL.

NICKEL PHOSPHATE VSB-5 (VERSAILLES SANTA BARBARA-5) AND SPHERICAL NICKEL PHOSPHATE NANOPARTICLES WITH AVERAGE DIAMETER OF 80 NM WERE SYNTHESIZED IN THE PRESENCE OF (2-HYDROXYETHYL) TRIMETHYLAMMONIUM AND TETRAPROPYLAMMONIUM HYDROXIDE AS TEMPLATE, RESPECTIVELY. CARBON PASTE ELECTRODES WERE MODIFIED BY NICKEL PHOSPHATE MOLECULAR SIEVES AND THE ELECTROCHEMICAL BEHAVIOR OF THE MODIFIED ELECTRODE WERE STUDIED USING CYCLIC VOLTAMMETRY. THE TRANSITION METAL IONS OF NI(II) WERE INCORPORATED TO THE NICKEL PHOSPHATE MOLECULAR SIEVES BY IMMERSION OF THE MODIFIED ELECTRODE IN 0.1 M NICKEL CHLORIDE SOLUTION FOR 5.0 MIN. THE MODIFIED CARBON PASTE ELECTRODE WAS USED AS ANODE FOR THE ELECTROCATALYTIC OXIDATION OF METHANOL IN ALKALINE MEDIUM.