Your company has been contracted to purify a new peptide mixture which has been produced by Pharmepere. Your research department has optimized the separation on two existing columns and the production department needs to know which column can operate at the highest volumetric flowrate. Since the stationary phase chemistries are slightly different, each column is operated at a different mobile phase mixture so you will need to take this into consideration for your calculations.

Column 1 Column 2
Mobile Phasae 50/50 Mobile Phasae 70/30
MeOH water by weight MeOH water by weight
dcol= 0.5cm dcol=1.0cm
Lcol= 25cm Lcol= 50cm
εc= 0.4888 εc=0.5330
dp= 10μm dp= 5μm

Due to pumping constraints, the maximum pressure for each system is 150 bar. Please determine which system can operate at the highest volumetric flowrate in mL/min. (Express your answer to 2 significant digits.) Note: εc= Interstitial Porosity

A3-mm-thick panel of aluminum alloy (k 177 w/m-k, c 875 j/kg-k and ? = 2770 kg/m) is finished on both sides with an epoxy coating that must be cured at or above t,-150°c for at least 5 min. the production line for the curing operation involves two steps: (1) heating in a large oven with air at ts,0-175°c and a convection coefficient of h, 40 w/m2. k, and (2) cooling in a large chamber with air at 25°c and a con- vection coefficient of he 10 w/m2.k. the heating portion of the process is conducted over a time interval te which exceeds the ime required to reach 150°c by 5 min (h = r + 300 s). the coating has an emissivity of ? = 0.8, and the temperatures of the oven and chamber walls are 175 and 25°c, respectively. if the panel is placed in the oven at an initial temperature of 25°c and removed from the chamber at a safe-to-touch tempera ture of 37°c, what is the total elapsed time for the two-step curing operation?