Relative humidify

The fuel cell is positioned within the magnet. Fuel gas (hydrogen) and oxidant gas (oxygen or air) are fed to the cell. For investigation of water transport in PEMFCs by MRI, it is preferable to operate PEMFCs in elevated temperature with humidity control, because both operating temperature and relative humidify (RH) inherently affects water transport in PEMFCs. Tsushima et al.27-29... 

Figure 5 shows the MRI visualization of the transversal water content distribution in the membrane in an operational PEMFC with variation of the current density.29 The cell temperature and relative humidify were 70°C and 92%, respectively. The vertical width of the images is about 1.0 cm across the gas channels, which is in the central part of the GDL. The horizontal width of the images is 600 xm. The anode is on the left side of each figure. Figure 6 shows one-dimensional water content profiles in the membrane that were obtained from MRI visualization results at variation of the relative humidity and current density. The horizontal axis and vertical axis respectively indicate the through-plane position of the... 

Jennings (1988) reviewed the literature on viscosity with regard to compiling exact measurements for the mean free path of air molecules. He considered both dry air and moist air. At 20°C Jennings gives a value of 1.8193 x 10-4 cP for the viscosity of dry air, 1.815 x 10-4 cP for air at 50 percent relative humidity, and 1.8127 X 10-4 cP for air at 100 percent relative humidify. These figures indicate that for most aerosol work, a value for viscosity at 20°C of 1.82 x 10 4 cP is reasonably accurate regardless of the humidity. 

The effects of time, temperature, and humidity on the vapor penetration of HNl and HNS into the forearm skin of human male volunteers were reported by NDRC (1945). Results of this work showed similar effects of temperature and humidity as observed for sulfur mustard, e.g. greater absorption with increased temperature and humidity. The penetration of HN1 and HNS was found to be linear with time (5 to 20 min for HNl and SO-60 min for HNS). At 71-72°F and 50-52% relative humidity, HNl penetration rate was 2.8 pg/cm /min and for HNS was 0.18 pg/cm /min at 72-7S°F and 45-48% relative humidity. At 86-87°F and 47-49% relative humidify, HNl penetration rate increased to 5.2 pg/cm /min and HNS penetration rate increased to O.S pg/cm /min at 85°F and 47 8% relative humidity. Excretion via the urine is likely a major route of elimination, especially due to the water solubihty of the immonium ion (see seetion IV). 

When specifying relative humidify, the associated temperature should also be specified. 

Process Requirements. Typical inside dry-bulb temperatures and relative humidifies used for preparing, processing, and manufacturing various products, and for storing both raw and finished goods, are listed in Table 1. In some instances, the conditions have been compromised for the sake of worker comfort and do not represent the optimum for the product. In others, the conditions listed have no effect on the product or process other than... 

It was shown that carbon foam is beneficial to humidification systems for fuel cells. The foam has demonstrated the ability to utilize waste heat from power electronics to both heat and humidify ambient inlet air to 80°C and 80% relative humidify. 

BALB/c mice, at weight of 20 2g, were used for in vivo gel formation and degradation test. The animals were purchased from the Laboratory Animal Center of Sichuan University. The animals were housed at controlled temperature of 20-22°C, relative humidify of 50-60% and 12h light-dark cycles. Free access to food and water was allowed. All the animals would be in quarantine for a week before treatment. All animal care and experimental procedures were conducted aceording to Institutional Animal Care and Use guidelines. 

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