Abstract: The invention is directed to a process for providing a gas having a minimum pressure and a composition that includes a major component to an end application, said process comprising the following steps:a) providing a first gas having said major component in a first concentration to said end application;b) providing means for measuring the pressure of said first gas being delivered to said end application;c) providing a second gas having a second concentration of said major component of said first gas which exceeds said first concentration;d) providing a third gas having a third concentration of said major component of said first gas which is less than said first concentration;e) providing means for mixing said second and said third gases so as to produce a fourth gas at at least said minimum pressure and which has said major component in a fourth concentration; wherein,f) when said means for measuring the pressure of said first gas to be received at said end application detects a deficiency with respect to sa

Abstract: The present invention relates to an ultra-high energy impact system for reducing the particle size of materials to an average diameter as small as about 40 .mu.m. The system includes a cooling station for cooling the materials to a temperature within the range of from about -40.degree. F. to about -450.degree. F. by direct contact with refrigerant, preferably liquid refrigerant; a milling station for reducing the particle size of the cooled materials which does not require direct cooling by refrigerant and which includes a rotor or rotors each operating at a tip speed within the range of from about 500 to about 1500 feet per second; and an atmosphere modifier for reducing the pressure of the gaseous atmosphere within the milling station to less than 20 inches of mercury absolute.