Engineering Answers

A cone of base diameter 40 mm and height 50 mm is resting centrally on the top of

square frustum whose smaller base is 40 mm, larger base is 50 mm and height 60 mm. The

square base frustum is resting on its smaller base. Draw an isometric view of the solids.

The engine mechanism shown in Fig. 8.38 has crank OB = 50 mm and length of connecting rod A B = 225 mm. The centre of gravity of the rod is at G which is 75 mm from B. The engine speed is 200 r.p.m

Do some extensive research on Maxwell's equation. Write a reflection paper about your learnings. You can use illustrations, figures, etc that would explain best your learning. Answer the following questions in your reflection paper:

1. What are the importance of each equation in your chosen field of study?
2. What are the application of each equation to your chosen field of study? Explain at least 1 concrete application.
3. What are Maxwell's equations and why are they important to your field of study?
4. What are the 4 maxwell's equations? What do they mean and what are their mathematical equation equivalent?

Solve by method of circular disk

1.    The area bounded by the parabola x² – 2x + y =3, the y – axis and the line y = 4, revolves about the line y = 4. Find the volume generated.

Solve by method of cylindrical shell

2.    The area bounded by the parabola y² + x - 2y =1, the x – axis and the line x =2 revolves about the line x=2. Find the volume generated.

A CSTR is fed with a solution of reactant A of concentration 10 kmol/m3

at a flow rate of 0.02

m3

/s. The product mixture from the first CSTR is fed into a second CSTR of twice the volume

of the first CSTR. The two CSTRs in series are required to achieve an overall conversion of

80%.

The reaction A → B is first order with respect to A (-rA = kCA) with a reaction rate constant of

0.2 s-1

. Assuming constant liquid density, what is the volume of the first CSTR?

T

A second order reaction is carried out at 313 K has an activation energy of 23 000 J/mole and

a rate constant is 2.6. For this reaction, at what temperature would the rate triple? What are the

units of the rate constant?

(NB Use Arrhenius equation)

Question 3 [20 Marks]

The following liquid-phase reaction is carried out in a semi-batch reactor:

A + 2B → C

The reaction is assumed to be zero order with respect to species A and B, and the specific rate

constant is 0.2 mol/dm3

-min.

Initially, the reactor volume is 60 litres and there are 80 moles of species A in the reactor.

Thereafter, a concentration of 12 moles per litre of species B is gradually added to the reactor

at a volumetric flow rate of 2 litres per minutes. How much time does it take to reach a 50%

conversion of species A?

(NB: Start from the general mole balance)

Hydrogen-free carbon in the form of coke is burned:

(a) With complete combustion using theoretical air

(b) With complete combustion using 50% excess air

(c) Using 50% air but with 10% of the carbon burning to CO only

As part of the preliminary design stages, you are required to calculate the gas analysis that will be

found by testing the flue gases on a dry basis.

One of the products of sewage treatment is sludge. After microorganisms grow in the activated sludge

process to remove nutrients and organic material, a substantial amount of wet sludge is produced.

This sludge must be dewatered, one of the most expensive parts of most treatment plant operations.

Disposing off the dewatered sludge is a major problem. Some organizations sell dry sludge for

fertilizer, some spread the sludge on farmland and in some places, it is burned. To burn a dried sludge

fuel oil is mixed with it, and the mixture is burned in a furnace with air.

As part of the design evaluation of the furnace the following analysis for the sludge and product gases

was collected:

Sludge (%) Product gas (%)

S 32 SO2 1.52

C 40 CO2 10.14

H2 4 O2 4.65

O2 24 N2 81.67

CO 2.02

a) Determine the weight percent of carbon and fuel oil

b) Determine the ratio of pounds of dry sludge to pounds of fuel oil in the mixture fed to the

furnace. [20]