Suppose that a one-celled organism can be in one of two states – either A or B. An individual in state A will change to state B at an exponential rate α; an individual in state B divides into two new individuals of type A at an exponential rate β. Define an appropriate CTMC for a population of such organisms and determine the appropriate parameters for this model.

Air is to be cooled in the evaporator section of a refrigerator by passing it over a bank of 0.8-cm-outer-diameter and 0.4-m-long tubes inside which the refrigerant is evaporating at -20°c. air approaches the tube bank in the normal direction at 0°c and 1 atm with a mean velocity of 4 m/s. the tubes are arranged in-line with longitudinal and transverse pitches of sl- st 1.5 cm. there are 30 rows in the flow direction with 15 tubes in each row. determine (a) the refrigeration capacity of this system and (b) pressure drop across the tube bank. evaluate the air properties at an assumed mean temperature of -5°c and 1 atm. is this a good assumption?

The higher the astm grain-size number, the coarser the grain is. a)-true b)-false

Hydraulic fluid with a sg. of 0.78 is flowing through a 1.5 in. i.d. pipe at 58 gal/min. the fluid has an absolute viscosity of 11.8 x 105 lbf-sec/ft2. is the flow laminar, turbulent or within the critical range? give both a numerical reynolds number and a term answer.