Gassing, direct

Corona discharge. During corona discharge pretreatment the plastic is bombarded by gasses directed toward its surface. 

The worn-out inmates were selected in the block or directly by the gate for gassing in Birkenau. A prisoner who was worn out was known as a Musselman. Musselmans were a permanent feature among the prisoners.. .. the same trucks which had taken the prisoners from the Monowitz hospital building came back immediately with the same things which the selected prisoners had worn. 

The transfer hydrogenation methods described above are sufficient to carry out laboratory-scale studies, but it is unlikely that a direct scale-up of these processes would result in identical yields and selectivities. This is because the reaction mixtures are biphasic liquid, gas. The gas which is distilled off is acetone from the IPA system, and carbon dioxide from the TEAF system. The rate of gas disengagement is related to the superficial surface area. As the process is scaled-up, or the height of the liquid increases, the ratio of surface area to volume decreases. In order to improve de-gassing, parameters such as stirring rates, reactor design and temperature are important, and these will be discussed along with other factors found important in process scale-up. 

Porter AE, Gass M, Muller K, Skepper JN, Midgley PA, Welland M (2007a). Direct imaging of single-walled carbon nanotubes in cells. Nature Nanotechnol. 2 713-717. 

Water or waste water ozonation - regardless of the scale of equipment - is mostly performed in directly gassed systems, where the ozone containing gas is produced by an electrical discharge ozone generator and is introduced into the reactor by some type of gas diffuser. Since two phases, the gas and the liquid, are required for the oxidation reaction to proceed as it does, they are also called heterogeneous systems. 

Another interesting point explored in detail by Wedler and Horn 87) is that the apparent binding constant of methionine sulfoximine for the irreversible inhibition is 100 jxM compared to 1.5 fiM for direct binding to the enzyme. This leads to speculation that perhaps methionine sulfoximine can bind to the enzyme in two conformations one for competitive binding that does not lead to irreversible inhibition, while another conformer binds in a different manner, producing the irreversible inhibition. The proposal from computer modeling studies of Gass and Meister 104) is that one conformation is responsible for both, but recent data open the door for further study and speculation. 

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