Abstract The process of the Membrane Electrode Assembly in the Proton Exchange Membrane Fuel Cell and the controllable variables: the pressure, the temperature, and the time of the hot pressure in the producing period would be discussed here. The experimental result of the MEA revealed that for Nafion112 and Nafion117 membranes, the conditions under the hot pressure are the same in the temperature. However, the pressure used in Nafion112 should be lower than Nafion117. In this case, the better function of the MEA can be achieved. Because Nafion112 is thinner, its water in the process of the hot pressure would be lost with extreme ease. This has a very serious impact on the function of the MEA. Therefore, to improve the MEA¡¦s function, the MEA should be boiled by water after being fabricated. The outcome of the research showed that for the purpose of improving the function of the MEA, some humidifier structure adding to the design of STACK is necessary. In order to be familiar to the related practical skills of STACK, PEMFC is brought into use for an electric bicycle in this research. Because the maximum power of STACK is only 150W, which is almost equal to the one-third power of the electric bicycles available such as the 400W of GIANT-Lafree electric bicycle. Besides, the speed of the electric bicycle is too slow when it is operated by itself, but it will be run more smoothly by the means of the assistant power. If the PEMFC electric bicycle can make more useful STACK and be redesigned, not be composed as it used to be, the use of the PEMFC electric bicycle will be steadier, more efficient, and more beneficial to the environment.

Abstract Semiconductor and optoelectrical industries are among the major high-technological enterprises in Taiwan. Many nitrogen-containing compounds such as monoethanol amine (MEA), 1-methyl-2-pyrrolidinone (NMP), 1-amino-2-propyl alcohol (APA) and hexamethylene disilazane (HMDS) are used in both manufacturing processes. These compounds may release to environments from waste gas or water sources and become environmental pollutants if not properly treated. The main purpose of this research was to investigate the biodegradation characteristics of the four compounds. The research was performed by using a 5-L sequencing batch reactor operated at a cycling time of 24 hrs that included a filling time of 0.5 hr, an aeration and reaction time of 21 hrs, a setting time of 2 hrs, and a drawing time of 0.5 hr. The reaction conditions were as follows for the activated sludge in the reactor: MLSS (mixed liquor suspended solids) = 2000-3000 mg/L, pH = 6.8-7.2, aeration intensity = 0.46 L air/(L liquor. min), F/M (food-to-microorganism ratio) = 0.2-0.5 kg COD/(kg MLSS. Day), and C0 (initial concentration of the target compound in the mixed liquor) = 100-800 mg/L. Results demonstrate that above around 80% of all the four compounds were degraded within the aeration time of 21 hrs, and the organic nitrogen was converted to NH3-N, NO2¡Ð-N, NO3¡Ð-N, N2,and biomass-N. For MEA, above 10 % of the NH3-N hydrolyzed from the compound was nitrified for loadings of less than 0.05 kg MEA-N/m3.day, and no nitrification was observed for loadings of above 0.20 kg MEA-N/m3.day. Approximate 3% of MEA-N was converted to biomass-N and the average nitrogen content in the sludge was 4.25%. With regards to NMP, around 5, 73-83, and 14-24% of the nitrogen was converted to NH3-N+NO2¡Ð-N+NO3¡Ð-N, N2, and biomass-N, respectively, and the average nitrogen content in the sludge was 5.6%. As for the biodegradation of APA, there occurred a filamentous sludge-bulking phenomenon when C0 = 400 or 800 mg/L. With C0 increased from 200 to 800 mg/L, there was an increasing rate of ammonia formation and decreasing rate of nitrification. For the compound, around 9, 74, and 13% of the nitrogen was converted to NO2¡Ð-N, N2, and biomass-N, respectively, at a loading of 0.0358 kg APA-N/m3.day. The conversions became 12, 66, and26%, respectively, for NO2¡Ð-N, N2, and biomass-N with the loading increased to 0.0716 kg APA-N/m3.day. The average nitrogen content in the sludge was 4.9%. HMDS was biologically degraded in the emulsion state with the help of surfactants Tween 80 and Span 80. With C0 increased from 200 to 800 mg/L, there was an increasing nitrification rate and nearly constant ammonia nitrite formation rates. Above 90% of HMDS-N was converted to N2 and a few of it to biomass-N. The average nitrogen content in the sludge was around 4.5%.

Abstract The experimental tests and analysis of single fuel cell unit are performance in this research, and the electrolyte in MEA(membrane and electrode assembly) we used Nafion 112.Accroding to change several design factors and operation conditions, we can find out how important the factors affect the PEMFC power output. The experimental conditions in this study are various of type of fasten torque, flow channels, oxidizers, catalyst type and loading in cathode side, materials of electron collector, inlet gas pressure and humidification of membrane. The results can provide us references to assemble a fuel cell stack in future. PEMFC can start quickly at low temperature and achieves stable output voltage. When the 4 N-m torque is applied to fasten the reaction chamber, the contact resistance between the electrode and electron collector reaches a minimum value. The results show that when the area ratio(Af /At)is 58.41%, we can have better ratio between channel areas and contact area, and the output can be larger. We found that increasing the loading of catalyst in the cathode, the power output rises up clearly, but the loading also has a limitation. By using gold to be the electron collector, the result shows that it has better performance than using graphite, but the price is also much higher. Our experiments display that use oxygen to be oxidizer can have better performance than use air. When we heated membrane in the water at 80¢J, it can resupply the water in the membrane, remain enough humidification of membrane can be clearly helpful to the PEMFC power output, because humidification can keep the proton conductivity of the membrane in good condition. And we also found while the hot press pressure at 160atm, the performance can be better than using other pressure. Key words : PEMFC¡BMEA¡BFlow area ratio

Ziel der Arbeit war es, dichte Neuronenkulturen in kleinere Untereinheiten zu unterteilen, welche durch ihre Neuriten miteinander in Kontakt standen. Zu diesem Zweck wurden auf MEAs zellbindende Kreisareale mittels Mikrostempeltechnik auf die zellabweisende Schicht aus Polyethylenglykol übertragen. Dudurch wurde gewährleistet, dass scharf abgegrenzte Neuronenareale für mehrere Wochen auf dem MEA wuchsen und nach Ausbildung der neuritischen Verbindungen untereinander, die elektrische Aktivität zwischen den Kreiskammern gemessen werden könnte. Das sollte Auskunft über Informationsausbreitung in Neuralnetzen geben und die Theorien über Synchronität und Synfirechains prüfbar machen. / It was the aim, to prodruce dense neural cultures and subdivide them into smaller units, which could communicate with each other via their neurites. For that purpose cell-friendly circular areals (PECM) were printed onto the MEA surface covered by a thin layer of Star-PEG. That should garantee that the cells grow in sharp-lined neuronal circles, that would grow for several weeks on the chip and that after they would have spread their neurites their electrical actions between the circles could be measured. That could provide future information about the synchronized spread of neural information.

In this thesis, the treatments of MEA and the special structures within carbon fiber bunch unipolar plates on the performance of PEMFC are studied. At first, the factors affecting on the water content within MEA will be studied. A passive HFC stack usually exposes in the ambient no matter that it works or not. However, the ambient is far from saturated. The water within MEA will vaporize continuously. Especially, if the stack is shutdown for a long period, there is no water generation in the cathode and then the membrane will be short in water. If it occurs, the conductivity of H+ will decrease greatly, and the electrode of MEA is also possible to separate from its membrane. This separation will make the performance of the stack an unrecovered decay. On the other hand, in order to improve the performance of a air-breathing HFC, the inner structure within cathode carbon fiber bunch unipolar plates is modified. The structure of the unipolar plates is modified in the following three aspects: 1. Increasing soft end height of carbon fiber bunch, 2. Increasing the number of silver-coated wires in carbon fiber bunch, 3. Cutting several serrated slots on the soft end of carbon fiber bunch. In the MEA treatment, firstly, a MEA is boiled in 80oC, 0.5M H2SO4 solution and then boiled in 80oC DI water for an hour, respectively. When the single-cell HFC operates in hydrogen inlet pressure 0.1 bar, air-breathing, and room temperature, experimental results display that the power density of this HFC with the aforementioned treatments and the special structure of unipolar plates can reach a value about 185mW/cm2. This value is about 130% higher than that of the untreated MEA and about 50% higher than that of the treatment of MEA only immersed in DI water. In addition, the comparison of the performance of HFC between with carbon fiber bunch unipolar plates and with graphite unipolar plates are also studied. The experimental result displays that the performance of HFC with the carbon fiber bunch unipolar plates is superior to that with graphite unipolar plates, especially the fuel cell operating under low gas inlet pressure.

To ran a DMFC without methanol crossover is the aim of this study.It is done by supplying fuel no more than what the anode can consume. The first is to explore the factors that may affect the time constant of vapor feed DMFC. In order to reduce the time constant of current decline, first, we decrease store tank¡¦s space of methanol with different structure of unipolar plate. Second, we reduce the thickness of anode stack and the space above the air bleed valve. Using slide plate instead of air bleed valve can shorten the diffuse distance effectively and reduce the time constant of current rise curve. The second is to explore the impact of supply of methanol on steady-state current of system. Using air bleed valve, because of its high gas tightness, the utilization rate of methanol can exceed 94% without crossover. It was found that in the slide plant experiment, steady-state current value depends mainly on the pore size of slide plate, and resistance value has nothing to do. However, the resistance value is lower, the time required to reach steady-state current is shorter. The third is to explore if the performance decay after long time test of steady-state current. It was found that the performance of MEA will decay while the water content of membrane decreased.

In this thesis, a PEMFC stack, which can be self-humidification of passive portable hydrogen fuel cell, will be developed. The stack is developed for portable applications, so the structure of the stack is simplified as possible as we can. As the cathode directly exposed under the atmosphere, so in a long time, the membrane easily lead to excessive evaporation of water, so that performance degradation. The traditional humidifier is more complex applications are not suitable for portable, so this thesis stack developed by the use of cotton capillarity, the water from the tanks transferred to the membrane, and then by cotton and a good touch to the membrane humidifier effect, this structure without an increase in large equipment, in line with the principles of portability. The PEMFC stack is made with carbon fiber bunches for current collectors and two 8-cell banded-type MEAs, the stack can develop a high voltage by serially connecting outside of the reaction chamber. 16-cell in series when the current density is greater than 110mA/cm2, use humidification to avoid long time operation, due to water cause a voltage drop. Humidification is not only to help transfer of hydrogen ions, and the role of a cooling stack, the cells temperature is too high will not cause transpiration rate of speed. Current density greater than 250mA/cm2, although humidity can still be effective, but insufficient humidification single cotton, one hour after, the voltage drop of about 20% longer cell performance, such as humidity will be no more have a more significant decline phenomenon, more cotton or additional external humidification humidifier can maintain a long-time stable operation. Therefore, the performance of the cells in order to avoid a recession, should pay attention to in a long time when working conditions and operating range.

The research of a hydrogen proton exchange membrane fuel cell is performed under certain designing and operational conditions. The water management technique is incorperated into the experimental work. The cell voltage vs. the current densities are studied by changing the stack reactive temperatures, the gas inlet temperatures and pressures, and the relative humidities in hydrogen stream. Eventually, we hope that these experimental results can provide the information about the optimizing conditions of fuel cells so that they can be used to design a high power multiple-cell fuel cell stack. A membrane and electrode assembly (called MEA) which contains a proton exchange membrane Nafion 112, anode catalyst Pt 0.4 mg/cm2, and cathode catalyst Pt 1.0 mg/cm2 is used in this experiment. The gas flowing area is about 58% of the total area. A proper heating and humidification equipment is applied in this experimental system. The experimental results show that the cell voltage at low current density is slightly influenced by the hydrogen inlet temperature; however, the cell voltage at high current density is strongly influenced by the humidity ratio of hydrogen stream. Raising the hydrogen pressure and the oxygen pressure at the same time can increases the cell voltage, but it is no obvious effects on the cell voltage when the gas pressure increases to more than 2 atm. When air is used as a oxidizer, increasing the inlet air temperature always reduces the cell voltage. With the hydrogen stream at saturated temperature 80¢XC, the assembly torque of the stack at 4 N-m, and the stack temperature at 80¢XC, the single fuel cell stack can always generate the best cell voltages at most of the current densities. At this time, the cell voltage at current density 1 A/cm2 already can reach a value higher than 0.6 V.

In this experiment, we are going to discuss the possibility of zero methanol crossover to the cathode target within the capacity of DMFC electrode and with proper methanol supply. After various trials, it is found that electrospray can be used to reduce fuel demand. The methanol will be consumed immediately within the electrode capacity. The methanol solution is volatile. As a result, the actual amount of electricity generated will never accord with the input. If we supply the electrode with methanol by direct contact using infusion pump, the volatility will be reduced. The total power generated then accords with the amount of methanol input. Although only low methanol concentration is supported currently, it¡¦s hoped that the crossover problem can be solved completely. In the electrode design, we try to take away the carbon cloth from the anode and leave the catalyst layer. By this way, the methanol is in touch with the catalyst. Such change is good for this experiment. In our study, following difficulties are found: (1) Methanol input (2) The impact of volatility in electrospray (3) When supplying fuels to the surface of electrode, the reaction size is too small. More attentions should be paid in the future cell design.

Rigorous CO₂ absorption models were developed for aqueous 4.5 m K+/4.5 m PZ, monoethanolamine (7m - 9m), and piperazine (8m) in Aspen Plus® RateSepTM. The 4.5 m K+/4.5 m PZ model uses the Hilliard thermodynamic representation and kinetics based on work by Chen. The MEA (Phoenix) and PZ (5deMayo) models incorporate new data for partial pressure of CO₂ vs. loading and kinetics from wetted wall column data. They use reduced reaction sets based on the more relevant species present at the expected operating loading. Kinetics were regressed to match reported carbon dioxide flux data using a wetted wall column (WWC). Density and viscosity were satisfactorily regressed to match newly obtained experimental data. The activity coefficient of CO₂ was also regressed to include newly obtained CO₂ solvent solubility data. The models were reconciled and validated using pilot plant data obtained from five campaigns conducted at the Pickle Research Center. Performance was matched within 10% of NTU for most runs. Temperature profiles are adequately represented in all campaigns. The calculated temperature profiles showed the effect of the L/G on the location and magnitude of the temperature bulge. As the L/G is increased the temperature bulge moves from near the top of the column towards the bottom and its magnitude decreases. Performance improvement due to intercooling was validated across the campaigns that evaluated this process option. Absorber intercooling was studied using various solvent rates (Lmin, 1.1 Lmin and 1.2 Lmin). It is most effective at the critical L/G where the temperature bulge without intercooling is in the middle of the column. In this case it will allow for higher absorption by reducing the magnitude of the bulge temperature. The volume of packing to get 90% removal with L/Lmin =1.1 at the critical L/G is reduced by 30% for 8m PZ. For MEA and a solvent flow rate of 1.1 Lmin packing volume is increased with intercooling at constant L/G. This increase is compensated by higher solvent loadings that suggest lower stripping energy requirements. The critical L/G is 4.3 for 8m PZ, 6.9 for 9m MEA and 4.1 for K+/PZ. / text