Retrogradation, stages

Katayama I., Maruyama S., Parkinson C. D., Terada K., and Sano Y. (2001) Ion micro-probe U-Pb zircon geochronology of peak and retrograde stages of ultrahigh-pressure metamorphic rocks from the Kokchetav massif, northern Kazakhstan. Earth Planet. Sci. Lett. 188, 185-198. 

There are those who see the emergence of sector standards as a retrograde step, having reached the stage where we have condensed all the world s national quality system standards into one group of 20 standards. Those following the development of ISO 9000 will already be aware that the 20 standards in the ISO 9000 family are soon to be reduced to four (ISO 9000, ISO 9001, ISO 9004, and a replacement for ISO 10011). It... 

A retrograde gas is produced through a three-stage separator system. The primary separator at 625 psia and 75°F produces 8885 scf/STB of 0.676 specific gravity gas. The second separator operates at 60 psia and 75°F. Stock-tank liquid gravity is 54.8°API. Estimate the specific gravity of the gas in the reservoir,... 

Volatile oils and retrograde gases are produced routinely through at least three stages of separation. Thus, the calculation procedure requires three gas-liquid equilibria calculations. The equations for producing gasoil ratios are... 

Compare your answers with the laboratory measured specific volume of reservoir liquid at bubble point, 0.0353 cu ft/Ib. 13-18, The gas-liquid equilibrium calculations for a two-stage separation of a retrograde gas have been completed. Results are given below. 

The gas-liquid equilibrium calculations for a three-stage separation of a retrograde gas have been completed. Results are given below. 

Gold et al. developed the following equation from three-stage separation of 237 retrograde gas samples.13 The average absolute error is 5.8%. 

The feed point should give the most equal slopes on both sides of the feed stage in a key ratio plot (Fig. 2,20). Too high a feed causes excessive retrograde distillation below the feed, and too low a feed causes excessive retrograde distillation above it. In order to reach the optimum feed point, the feed stage should be moved from the sharp maximum (or minimum) toward the flat one (Fig. 2.20). 

Pyelonephritis develops as a result of bacterial infection or from retrograde infection through the ureter. In the acute stage, bacterial infection is accompanied with infiltration with inflammatory cells and the development of edema. Obstructive nephropathy develops in chronic stages of bacterial infection. 

Fig. 14.6. Application of ion implantations in advanced CMOS structure at several stages of the process, (a) Ion implants for retrograde well formation, punch-through-stop, and threshold voltage adjust (b) shallow source/drain (S/D) implant and (c) halo implant...

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