A rectangular beam has a width of 300 mm and an effective depth
of 510 mm. It carries Vu = 200 KN and Mu = 55 KN-m and is
reinforced with 2650 mm2. Use f’c = 21 MPa and fy = 345
MPa. Normal concrete. Express your answer in two decimal
places.
a. Compute the shear strength in KN provided by concrete using
the less conservative formula as shown. Express your answer in two
decimal places.
b. Calculate the required...
Air flows through a short duct with a smooth inside surface and
gradually changing flow area. The measured flow rate is equal to
288 lbm/min. At the duct inlet, the temperature is equal to 82 deg
F, and the pressure is equal to 15 psia. The inlet velocity is
equal to 924 ft/s. At the duct exit, the pressure is equal to 21.7
psia. (I.) Calculate the cross-sectional flow area of the duct
inlet. (II.) Estimate the temperature and velocity...
A prestressed concrete beam with a rectangular sectin 120 mm
wide by 300 mm deep supports a a live load of 3 kN/m. The spanning
over 6 m is prestressed by a straight cable carrying an effective
prestressing force of 200000 N located at an eccentricity of 55 mm,
the density of concrete 24 kN/m3. Find : (1)- The resultant stress
distribution for the centre of span cross section of the beam (2)-
the presressing force which can balance the...
Arrive at the size of the rectangular RCC footing for a
column of size 300 mm × 450 mm supporting an axial service load of
1200 kN. The SBC of soil is 200 kN/m2. Take M30 grade
concrete, Fe415 steel, the angle of internal friction of soil is
300 and unit weight of soil is 19
kN/m3.
Air is cooled from 300 K to 273 K as it flows steadily through a
duct. Frictional dissipation may be neglected. Cooling is achieved
by removing heat via a heat pump. The work requirement is 1.15
times that of a reversible heat pump operating between 263 and 310
K. For each mole of air flowing through the duct, calculate: Air
can be assumed an ideal gas with a constant heat capacity cP of
3.50R. The temperature of the surroundings is...
Air flows through a 0.25-m-diameter duct. At the inlet the
velocity is 300 m/s, and the stagnation temperature is 90°C. If the
Mach number at the exit is 0.3, determine the direction and the
rate of heat transfer. For the same conditions at the inlet,
determine the amount of heat that must be transferred to the system
if the flow is to be sonic at the exit of the duct.
Air (280 K and atmospheric pressure) enters a 3-m-long
rectangular duct (0.15 m by 0.075 m) whose surface temperature is
at 400 K. Air mass flow rate is 0.10 kg/s. Find the heat transfer
and the outlet temperature. Use the Sieder-Tate equation to solve
for the heat transfer coefficient.
Hot air flows with a mass flow rate of 0.05 kg/s through an
insulated square duct with side of 0.15m, the hot air enters at 103
oC and after a distance of 5m, cools to 85
oC. The heat transfer coefficient between the duct outer
surface and the ambient air (Tair = 0 oC) is
6 W/m2 K.
Calculate the heat transfer coefficient between hot air and duct
inner wall.
Air Cp = 1.011 KJ/kg K; air k = 0.0306...
1. What is the osmotic concentration of a solution containing
300 mM NaCl and 100 mM glucose? Is it iso-, hypo-, or hyper-
osmolar?
A.
700 mOsm/L, hyper-osmolar
B.
600 Osm/L, iso-osmolar
C.
200 Osm/L, hypo-osmolar
D.
400 mOsm/L, hyper-osmolar
2. Ocean water has a high salt concentration compared to body
fluids. If you were adrift at sea drinking seawater will not help
you, and may make you even more dehydrated! What explains this?
A.
Water diffuses from body tissues...
Air at 60oC and 1 atm enters a smooth tube having a diameter of
2 cm and length of 10 cm. The air velocity is 40 m/s: 1- What
constant heat flux must be applied at the tube surface to result in
an air temperature rise of 5oC? 2- What average wall temperature
would be necessary for this case?
Answer: (1) qs = 11841W/m2 (2) Tw = 97oC