Airflow method comparison

Cathode Recycle. Air from the cathode exhaust is recycled to the cathode inlet and increases the air temperature from the compressor by mixing. As with the previous case, this method requires certain compressor airflow to achieve the required A T across the fuel cell. Two methods for achieving cathode recycle are commonly considered. A high temperature blower powered by an electric motor can be used to recycle the flow. Also, an ejector uses the compressor as the primary flow to recycle the cathode air. These comparisons will assume a blower is used. 

The method described in this ehapter represents a first attempt to qnantitatively relate the skin disposition of volatile ehemieals to their physieal properties and to envi-romnental eonditions, inelnding variable temperature and airflow over the skin smface. The relationships were developed for fragrance ingredients however, it is likely they can be extended to inelnde other important classes of componnds sneh as noncorrosive industrial solvents, pestieides, herbicides, and (noncorrosive) ehem-ical warfare agents. Drawing the comparison to steady-state skin permeability models in which much more is known, it is evident that considerable experience must be gained with the use of such models before widespread acceptance may be expected. Areas for further attention are outlined next. 

The first methods of evaporation rate classification were based on a certain standardisation of the conditions under which the evaporation takes place and on comparison of the results with that of a reference solvent. An example is the evaporation of a small quantity of solvent from filter paper and comparing the drying time of the solvent under consideration to that of diethyl ether. The test procedure is given in the German DIN Method 53170 in more detail. It prescribes the use of equal volumes of solvent on a specified filter paper at 20 C, 65% relative humidity and no airflow. The relative evaporation time, RET equals the ratio of the evaporation times of test solvent and diethyl ether ... 

---