The outputs of registers R0, R1, R2, and R3 are connected through 4-to-1 multiplexers to the inputs of a fifth register, R4. Each register is 8 bits long. The required transfers, as dictated by four control variables, are Co = R4 ← Ro
C1= R4 ← R1
C2= R4 ← R2
C3= R4 ← R3

The control variables are mutually exclusive (i. e., only one variable can be equal to 1 at any time) while the other three are equal to 0. Also, no transfer into R4 is to occur for all control variables equal to 0.

a. Using registers and a multiplexer, draw a detailed logic diagram of the hardware that implements a single bit of these register transfers.
b. Draw a logic diagram of the simple logic that maps the control variables as inputs to three outputs: the two select variables for the multiplexer and the load signal for the register R4.

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?