This question is incomplete, the complete question is;
Determine the design moment strength (ϕMn) for a W21x73 steel beam with a simple span of 18 ft when lateral bracing for the compression flange is provided at the ends only (i.e., Lb = 18 ft). Report the result in kip-ft.
Use Fy=50 ksi and assume Cb=1.0 (if needed).
Answer: the design moment strength for the W21x73 steel beam is 566.25 f-ft
Explanation:
Given that;
section W 21 x 73 steel beam;
now from the steel table table for this section;
Zx = Sx = 151 in³
also given that; fy = 50 ksi and Cb = 1.0
QMn = 0.9 × Fy × Zx
so we substitute
QMn = 0.9 × 50 × 151
QMn = 6795 k-inch
we know that;
12inch equals 1 foot
so
QMn = 6795 k-inch / 12
QMn = 566.25 f-ft
Therefore the design moment strength for the W21x73 steel beam is 566.25 f-ft
Answer:
The conversion in the real reactor is = 88%
Explanation:
conversion = 98% = 0.98
process rate = 0.03 m^3/s
length of reactor = 3 m
cross sectional area of reactor = 25 dm^2
pulse tracer test results on the reactor :
mean residence time ( tm) = 10 s and variance (∝2) = 65 s^2
note: space time (t) =
t =
Vo = flow metric flow rate , L = length of reactor , A = cross sectional area of the reactor
therefore (t) =
= 25 s
since the reaction is in first order
X = 1 - 
= 1 - X
kt = In 
k = In
/ t
X = 98% = 0.98 (conversion in PFR ) insert the value into the above equation then
K = 0.156 
Calculating Da for a closed vessel
; Da = tk
= 25 * 0.156 = 3.9
calculate Peclet number Per using this equation
0.65 = 
therefore

solving the Non-linear equation above( Per = 1.5 )
Attached is the Remaining part of the solution
Answer:
The convective coefficient is 37.3 W/m²K.
Explanation:
Use Newton’s law of cooling to determine the heat transfer coefficient. Assume there is no heat transfer from the ends of electric resistor. Heat is transferred from the resistor curved surface.
Step1
Given:
Diameter of the resistor is 2 cm.
Length of the resistor is 16 cm.
Current is 5 amp.
Voltage is 6 volts.
Resistor temperature is 100°C.
Room air temperature is 20°C.
Step2
Electric power from the resistor is transferred to heat and this heat is transferred to the environment by means of convection.
Power of resistor is calculated as follows:
P=VI

P= 30 watts.
Step3
Newton’s law of cooling is expressed as follows:

Here, h is the convection heat coefficient and
is the exposed surface area of the resistor.
Substitute the values as follows:


h = 37.3 W/m²K.
Thus, the convective coefficient is 37.3 W/m²K.