Flow divider and/or combiner valves are hydraulic components which are used to divide and/or combine flow in a predetermined ratio independent of loading conditions. Over the past years the authors have successfully designed valves which can divide and/or combine flow with an error of less than 3 percent for all loading conditions. More recently, a valve which can be used to divide and combine flow for a wide range of flow requirements and still maintain an error of less than 3 percent has been developed and has been labeled an “auto-regulated high precision flow divider/combiner valve”. The heart of the auto-regulated valve is the autoregulator itself. In this paper, the operation of the regulator is discussed and design criterion for acceptable performance presented. A linearized model is developed from which a number of valve parameters are established. A more complex model using the Power Bond Graph technique is presented, and transient responses to different flow inputs are compared to experimental data. The model and experimental responses were in good agreement; hence, it was concluded that the model could be used with confidence in future stability studies.

Normal rabbits were exposed to single, subanesthetitizing doses of chloroform vapors and a regular decrease in their total serum cholesterol was found. In rabbits with abnormally high serum cholesterol levels, however, no consistent changes were observed. In control experiments it was found that in the normal rabbit there is a diurnal variation in serum cholesterol, with lowest values around 4 p.m. No consistent changes were found in the serum cholesterol of rabbits after being submerged for brief periods in ice water. METHODChloroform Experiment. Blood samples (4 to 8 ml.) were taken from the marginal ear vein of 13 normal rabbits. The animals were then placed 219