Which of the following types of mould will have the longest period of cooling time for the same castings?

Which one of the following is the correct sequence of various stages of operating cycle of a manufacturing company? 1. Raw material conversion period, work-in-progress conversion period, Finished goods conversion period, Receivables conversion period 2. Raw material conversion period, work-in-progress conversion period, Creditors payment period, Receivables conversion period 3. Creditor payment period. Raw material conversion period, Receivables conversion period, work-in- progress conversion period 4. Raw material conversion period, Finished goods conversion period, work-in- progress conversion period. Receivables conversion period

A

1

B

2

C

3

D

4

Consider the following statements for cooling towers: 1. Cooling tower is an artificial device used to cool the hot cooling water coming out of condenser more effectively. 2. The amount of water usually lost with induced draft cooling tower ranges from 5% to 6% by evaporation. 3. The amount of water usually lost with induced draft cooling tower ranges from 7% to 8% by drift losses. 4. The rate of evaporation of water and its cooling effect on the remaining water depends upon the relative humidity of air passing through the tower. Which of the above statements are correct?

A

1 and 4 only

B

1 and 3 only

C

2 and 3 only

D

1, 2, 3 and 4

At the mould exit of a continuous caster, the metal consisting of a solidified shell with a liquid metal core exits at the rate of 35 kg S^-1. Given that the latent heat of fusion is 3 × 10⁵ J kg^-1 and the total rate of heat removal by the mould is 4.2 × 10⁶ W, the mass fraction of solid at the mould exit is . . . . . . . .
Assume that both while solid and liquid remain at the melting point, they are in the mould.

A

0.1

B

0.4

C

0.8

D

1.5

Water cooling is always preferred than the air cooling for the extraction of heat from the castings through the mould.

A

True

B

False

When a pattern is to be withdrawn from the mould, it is first shaken, by striking over it from side to side, so that its surface may be free of the adjoining sand wall of the mould. That causes the size of the mould cavity increases a little and a negative allowance is to be provided in the pattern to compensate the same, is known as:

A

Draft allowance

B

Rapping allowance

C

Machining allowance

D

Shrinkage allowance

The bypass factor, in case of sensible cooling of air, is given by (where td₁ = Dry bulb temperature of air entering the cooling coil, td₂ = Dry bulb temperature of air leaving the cooling coil, and td₃ = Dry bulb temperature of the cooling coil)

A

(td₁ -td₃)/( td₂ -td₃)

B

(td₂ -td₃)/( td₁ -td₃)

C

(td₃ -td₁)/( td₂ -td₃)

D

(td₃ -td₂)/( td₁ -td₃)

The bypass factor, in case of sensible cooling of air, is given by (where td₁ = Dry bulb temperature of air entering the cooling coil, td₂ = Dry bulb temperature of air leaving the cooling coil and td₃ = Dry bulb temperature of the cooling coil)

A

$$\frac{{{\text{t}}{{\text{d}}_1} - {\text{t}}{{\text{d}}_3}}}{{{\text{t}}{{\text{d}}_2} - {\text{t}}{{\text{d}}_3}}}$$

B

$$\frac{{{\text{t}}{{\text{d}}_2} - {\text{t}}{{\text{d}}_3}}}{{{\text{t}}{{\text{d}}_1} - {\text{t}}{{\text{d}}_3}}}$$

C

$$\frac{{{\text{t}}{{\text{d}}_3} - {\text{t}}{{\text{d}}_1}}}{{{\text{t}}{{\text{d}}_2} - {\text{t}}{{\text{d}}_3}}}$$

D

$$\frac{{{\text{t}}{{\text{d}}_3} - {\text{t}}{{\text{d}}_2}}}{{{\text{t}}{{\text{d}}_1} - {\text{t}}{{\text{d}}_3}}}$$

In permanent mould casting, the mould is pre-heated to its operating temperature before the actual use of mould.

A

True

B

False

Continuous passing of Co2 through the mould can decrease the strength of mould and results in a weak mould.

A

True

B

False

Faster and uneven cooling of hot casting affects the castings badly or may cause several defects in the castings.

A

True

B

False

Which of the following types of mould will have the longest period of cooling time for the same castings?

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