Direct single cell tests

The single fuel cell test is one of the most direct and effective methods for the evaluation of catalyst layers and MEAs. Even if the results obtained by a half-cell test are very promising, the single-cell test is still a necessary step for performance validation of the developed catalyst layer and MEA. 

Future Uses. The most recent uses for methanol can be found in the agricultural sector. Test studies are being carried out where methanol is sprayed directly onto crops to improve plant growth. Methanol can be used as a carbon source for the production of single-cell protein (SCP) for use as an animal feed supplement. The process has been commercially demonstrated by ICl at their BiUingham, U.K., faciUty. However, the production of SCP is not commercially practical at this time, in comparison to more conventional protein sources. 

In order to sustain life, a bioartificial liver device should contain at least 10-30% of the normal liver mass (i.e., 150-450 g of cells in the case of an adult). In a bioartificial liver device, the animal or human liver cells can conceivably be cultured and used in several forms, including (i) independent single-cell suspensions (ii) spheroid (i.e., globular) aggregates of cells of 100-150 pm diameter (iii) cylindroid, rod-like aggregates of cells of 100-150 pm diameter (iv) encapsulated cells and (v) cells attached to solid surfaces, such as microcarriers, flat surfaces, and the inside or outside of hollow fibers. In order to facilitate mass transfer, a direct contact between the cells and the blood seems preferable. Among the various types of bioartificial liver device tested to date, four distinct groups can be identified [19] ... 

Heteropolyacid-modified polymer silica membranes for Direct Methanol Fuel Cells have been prepared and tested under high temperature operation conditions (145°C) in single cell configuration. A maximum power density of 0.4 W/cm in oxygen with 2 M methanol has been obtained with air at the cathode, this value decreased to 0.25 W/cm. The higher performance of the heteropolyacid-Nafion-silica membrane, with respect to Nafion-silica, is attributed to its better ion transport properties, since the measured cell resistance value is similar for both membranes. 

While clever experimental design may make it possible to test predictions of single-cell models without recourse to measurements of f, direct experimental access to the frequency function is often desirable and sometimes necessary in order to evaluate single-cell control and kinetic properties using the strategy just outlined. 

The cationic character of the imidazole group has been exploited by aUcali-doping of PBI polymers with the stmcture shown in Fig. 6.10. Hou et al. [222-224] have prepared AEM by doping of PBI with KOH and tested the membranes in a direct methanol single cell, while the permeabihty of ethanol through PBI has been studied [225], as well as the performance of DEFC using PBI [226, 227]. 

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