Inert gas exchange

The Role of Inert Gas Exchange and Population Statistics in Studies of Decompression Sickness... 

Mass transfer models were combined with dose-response analyses to yield more insight into the fundamental etiology of decompression sickness. Data are presented that would favor a four-tissue model of a hamster from an inert gas exchange point of view (1) lung, (2) a fast tissue with a time constant corresponding to the cardiac output per gram of tissue, and (3, 4) two slow tissues (time constant 6.3 and 25.5 min) corresponding to those tissue sites susceptible to bubble nucleation. 

Two types of studies were carried out the first, reported on a preliminary basis (8), involves the use of an endpoint—death—and is oriented towards the articulation of the receptor sites for bubble nucleation. The second study, reported here for the first time, involves a measurement of the fast inert gas exchange constants of the animal model. Both studies utilized air as a breathing mixture and were begun with the animal assumed to be in equilibrium with air at 1 atm (Pn2 = 0-79 ata). 

Ton-exchange systems in process appHcations may be batch, semicontinuous, or continuous. Batch operations are not common but, where used, involve a ketde with mechanical agitation. Injecting with air or an inert gas is an alternative. A screened siphon or drain valve is requited to prevent resin from leaving with the product stream. 

Fire or explosion hazards require special motor enclosures. Hazards include combustible gases and vapors such as gasoline dust such as coal, flour, or metals that can explode when suspended in air and fibers such as textile lint. The land of motor enclosure used depends on the type of hazard, the type and size of motor, and the probability of a hazardous condition occurring. Some available enclosures are explosionproof motors, which can withstand an internal explosion force-ventilated motors cooled with air from a safe location and totallv enclosed motors cooled bv air-to-water heat exchangers and pressurized with safe air, instrument air, or inert gas,... 

Inert gas-filled motors can also be used in refineries and chemical plants, but their applications are limited. They have tightly fitted covers and oil seals around the shaft to minimize gas leakage, are continually pressurized with an inert gas or instrument air, and are equipped with an internal air-to-water heat exchanger. Inert gas-filled motors are suitable for any hazardous location but require auxiliaries such as cooling water, gas pressurizing system, and control accessories. 

Furthermore, no significant differences are observed on the methane conversion or on the ignition temperatures of the Pd2HZSHe and the Pd2HZS02 catalysts. This result presumes that the catalyst pre-treatment with oxidant or with inert gas has the same effect on the activity of the Pd-HZSM-5 catalysts prepared by the solid-exchange method. Moreover, a noticeable methane conversion increase is observed when the NaZSM-5 support is used instead of the HZSM-5 zeolite. The ignition temperatures... 

The thermal decomposition, at least in the early stages, is reversible, as shown by the higher decomposition temperature in the presence of hydrogen than in vacuum or inert gas, and also by the existence of a rapid isotopic exchange between tetrahydroboride and deuterium at T > 625 K (Ziittel et al., 2003). 

The feed system consisted of a reservoir, a plunger-type feed pump, a twin-fluid atomising nozzle (giving a round spray of angle 13° in free air) and a mini-compressor. Inert gas for the twin-fluid nozzle was drawn between the outlet of the heat exchanger and the rotameter... 

The binuclear hydride salts are air sensitive, soluble in THF, acetone, CH3CN, MeOH, and diethyl ether, and insoluble in hydrocarbon solvents. They can be stored cold under an inert gas or in vacuo for several months. The salts tend to slowly decompose into W(CO)6 and [PPN] [FeH(CO)4], Carbon monoxide rapidly (within minutes) degrades the dimer into the same products.5 The salts react rapidly with CH3COOD or stronger deuterated acids to form the H-D exchanged products, [FeCrD(CO)9]. The hydrides also act as catalysts in olefin isomerization.10... 

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