Calculate the heat flux and overall heat transfer coefficient for two-layer wall, which consists of bricks - l1=0,5 W/(m∙K), and the insulating material - l2=0,05 W/(m∙K). Layer thickness are as follows: s1=0,3, s2=0,2 m, respectively. The temperatures on the outer surface of walls are: bricks t1=10oC, insulation t2 = –5oC. Inside and outside air tempe-ratures are: tin=20oC, and tout= –10oC, respectively.

A large cylindrical vessel is used as a batch reactor and is perfectly mixed.
The liquid inside is heated to keep the reactants at an elevated temperature.
Heat is lost through the portion of the vessel walls that is in contact with the liquid
contents, corresponding to an area of 25.9 m2
. The overall heat-transfer
coefficient, U, is 200 W m-2 K-1
.
The temperature of the ambient surroundings is 15 ºC, the mass of liquid in the
tank is 12.7 x 103
 kg, and its specific heat capacity is 3000 J kg-1 K-1. There is no
flow into or out of the tank. The contribution of any chemical reactions to the heat
balance is very small, and should be neglected.
(a) Determine the rate of heating required to keep the contents of the tank at a
steady-state temperature of 100 ºC.
[2 marks]
(b) At a given moment (at t=0), it starts to rain. This causes an increase in the
rate of heat loss from the tank, manifested in a 10% increase in the overall
heat-transfer coefficient. The ambient temperature has not changed.
i. What is the steady-state gain in the temperature of the tank
contents, in response to changes in U? 

Figure Q5(a) shows a continuous reinforced concrete beam of three equal spans 8 m
each. The beam carries uniformly distributed load over its entire span which consists of
characteristic dead load (including self-weight) of 25.0 kN/m and characteristic imposed
load of 10.0 kN/m. The beam cross section with the designed reinforcement is shown in
Figure Q5(b). The construction materials used in the design are Grade C35 concrete and
Grade 500 steel reinforcement. The nominal concrete cover to links is 30 mm, while the
elastic modulus of concrete and steel are 33 kN/mm2
and 200 kN/mm2
respectively. The
estimated creep coefficient is 2.3 and the final shrinkage strain is 280 x10-6
.
Calculate the long term deflection of the beam at mid span A-B at serviceability limit
states.
 

Aluminium has a density of 2.7 g/cm³ and a specific heat of 0.9 J/g.⁰C. A 9.7 cm³ piece of Aluminium at an initial temperature of 125 ⁰C is dropped into an insulated container with 120 g water initially at 18 ⁰C. What will the final temperature of the Aluminium-water mixture? (Specific heat of water: 4.186 J/g.⁰C)