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Between May 16 and July 1,1973, four definite cases and one possible case of clinical salmonellosis occurred in a 175-bed community hospital; there were no deaths. Three of the four patients with definite salmonellosis had had cholecystectomies done by the same general surgeon (A); the fourth was an intensive care unit nurse who cared for one of the ill patients during the diarrheal phase of illness before salmonellosis was diagnosed. Epidemiologic investigation implicated the plastic tubing of an intermittent-suction machine located in the recovery room as the environmental reservoir of the organism, and having a nasogastric tube in place postoperatively was the critical host factor related to illness. The salmonella organisms isolated from the suction machine tubing were identical in serologic reaction, biochemical test results, and bacteriophage susceptibility pattern to those recovered from the four patients with confirmed salmonellosis. Antimicrobial susceptibility patterns were similar but not identical.

A numerical study was conducted to evaluate the loss sensitivity of shrouded vs. unshrouded turbine rotor blades. Accuracy is demonstrated with a series of grid independence studies. Application of the methods is performed through various studies related to the effects of shrouding a High-Pressure Turbine (HPT) rotor blade for a NASA-specified N+3 timeframe single-aisle aircraft engine at takeoff conditions. Flat, Recessed, and Shrouded rotor configurations are evaluated at tip clearances from 0.25% to 4% of blade span. Mach # distributions, near-tip blade loading, and other flow characteristics are examined. Plots of stage efficiency vs. tip clearance are presented, with trends compared to available experimental data. It is shown that for the imposed boundary conditions, the addition of a shroud improves stage efficiency and significantly reduces sensitivity to tip clearance at higher clearance fractions. A casing recess is also shown to slightly increase sensitivity to tip clearance for tip clearances greater than 0.5%. Total pressure loss profiles vs. blade span are also compared, providing insight into the mechanisms behind the performance of the three configurations.