2. the concentration of ubod in a river entering the first of two lakes that are connected in series is equal to 20 mg/l. if the first-order bod reaction rate constant (k) equal to 0.35/d and complete mixing in each lake, what is the concentration of ubod at the outlet of each lake? the flow in the river is equal to 4000 m3/d and the volume of the first and second lake is 20,000 and 12,000 m3, respectively. assume steady-state conditions.

Adouble-strand no. 60 roller chain is used to transmit power between a 13-tooth driving sprocket rotating at 300 rev/min and a 52-tooth driven sprocket. a) what is the allowable horsepower of this drive? b) estimate the center-to-center distance if the chain length is 82 pitches. c) estimate the torque and bending force on the driving shaft by the chain if the actual horsepower transmitted is 30 percent less than the corrected (allowable) power.

The drive force for diffusion is 7 fick's first law can be used to solve the non-steady state diffusion. a)-true b)-false

At 12 noon, the count in a bacteria culture was 400; at 4: 00 pm the count was 1200 let p(t) denote the bacteria cou population growth law. find: (a) an expression for the bacteria count at any time t (b) the bacteria count at 10 am. (c) the time required for the bacteria count to reach 1800.