Low-molecular-weight gas

On firings the gases from the propellant accelerate the piston that compresses the light gas in front of it. At a preestablished pressure, the projectile is propelled down the launch tube accelerated by the low molecular weight gas which follows the projectile to the mouth of the tube. The target material is placed in front of the launch tube, and appropriate instmmentation used to estabUsh the characteristics of the interface reaction between projectile and target (117-120). 

Solubility of low molecular weight gas goes down with temperature, but inorganic salt solubility goes up with temperature ... 

The most cost-effective way to produce a high polytropic head is to increase the number of wheels on the rotor. But the longer the rotating assembly, the more difficult it is to properly balance the rotor. Especially for high-speed machines, rotors which become unbalanced are subject to destructive vibration. Therefore, for low-molecular-weight gas services (less than 10), it is not uncommon to use reciprocating compressors. 

A number of important sample preparation techniques rely upon gas extraction or the analysis of samples in the gas phase. These samples usually contain low concentrations of volatile analytes and higher concentrations of water vapor in a low molecular weight gas or air. Direct sample introduction by syringe or valves is only suitable for small volumes of relatively concentrated samples (section 3.4.2). More common sample introduction methods involve analyte accumulation by sorbent or cryogenic trapping followed by vaporization in the presence of a flow of gas to transport the... 

It is possible that one product may escape from the reaction medium (a low molecular weight gas, for example). 

Propellants A combination producing high reaction temperature, a large volume of low molecular weight gas, and a rapid burning rate is needed. Charcoal and organic compounds, such as polybutadiene, are often found... 

Surge This is a terrifying sound that centrifugal compressors make when they malfunction either due to low flow or excessive discharge pressure, or low molecular weight gas. 

There are only two real problems with reciprocating compressors pulsation and mechanical reliability. But these problems are so intractable that, for most industrial applications, centrifugal compressors are preferred the exception is when dealing with low molecular weight gas. A low molecular weight gas, such as hydrogen, has a low density. Let s say that a compressor must develop a large differential pressure or AP. Recall Eq. (41.1) from the previous chapter ... 

For low molecular weight gas (MW less than 10) and high head requirement, coitrifuga] compressor may not be a good candidate for the compression service, and reciprocating or notary compressor may be required. 

Low molecular weight gas is easy to slip in cylinder from discharge side to suction. This will reduce the volumetric efficiency and a larger compressor is required. 

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