Neutral Molecule Desorption from SS(304) and A1(6061) Due to Particle Bombardments
The pressure in both electron and proton storage rings is dependent on the particle wall bombardment molecular desorption rates due in one case (proton storage rings) to ~ keV ions while in the other to ~ 100 eV electrons. Also in order to minimize secondary electron amplification effects in both types of machines the secondary electron emission coefficient should be as low as possible. The above quantities have been measured on A1(6061) and SS(304) materials having had various treatments including a sputter deposition of Ti and TiN in the case of A1. The results indicate for both electron and proton storage rings that SS(304) materials properly prepared have particular advantages over A1 considering both molecular desorption yields and secondary electron emission effects.
Secondary electron amplification in high energy proton accelerators
Abstract A model is presented which may result in secondary electron growth during multiampere, bunched beam operation of proton accelerators or storage rings.
Effect of spray nozzle design on liquid-solid contact in fluidized beds
Abstract In industrial fluid cokers the feedstock, consisting of heavy bituminous hydrocarbons, is atomized with steam and injected into a hot fluidized bed of coke. Good and uniform contact of the liquid droplets with the solid particles is required to provide heat for the cracking reactions while minimizing mass transfer effects. Experiments in a pilot plant coker have suggested that the initial particle/liquid mixing, in the spray jet, is rather poor. Experiments in a X-ray scanner showed that liquid droplets and entrained particles accumulate just below the tip of the jet plume to form agglomerates. An experimental technique was used to quantitatively determine the quality of mixing with a variety of nozzle configurations including several novel designs. By improving spray stability, redistributing liquid droplets to the solids-rich region of the jet and increasing the surface area of the gas–liquid jet-fluidized bed interface, liquid/solid contact is improved.