Which is the earliest and most widely used shell that came with the UNIX system?

In case of a shell and tube heat exchanger, the minimum shell thickness for carbon steel (inclusive of corrosion allowance) depends on shell diameter and is in the range of __________ mm.

A

3-5

B

5-11

C

8-15

D

12-18

In a shell and tube heat exchanger, putting a longitudinal baffle across the shell, forces the shell side fluid to pass __________ through the heat exchanger.

A

Once

B

Twice

C

Thrice

D

Four times

A thin spherical shell of internal diameter d is subjected to an internal pressure p. If $${\sigma _{\text{t}}}$$ is the tensile stress for the shell material, then thickness of shell is equal to

A

$$\frac{{{\text{pd}}}}{{{\sigma _{\text{t}}}}}$$

B

$$\frac{{{\text{pd}}}}{{2{\sigma _{\text{t}}}}}$$

C

$$\frac{{{\text{pd}}}}{{3{\sigma _{\text{t}}}}}$$

D

$$\frac{{{\text{pd}}}}{{4{\sigma _{\text{t}}}}}$$

In Bourne shell, which file sets the Unix environment for the user when the logs into his HOME directory.

A

.exrc

B

.profile

C

lastlogin

D

.mbox

E

None of the above

Which of the following special shell variables is used to process number of the current shell?

A

$!

B

$$

C

$0

D

$*

E

None of the above

Baffles are provided in a shell and tube heat exchanger to increase the turbulence and velocity of the shell side fluid. Which of the following shaped baffles does not fall in the category of transverse baffle?

A

Segmental baffle

B

Flat plate extending across the wall

C

Disk type baffle

D

Helical type baffle

In case of a shell and tube heat exchanger, the minimum and maximum baffle spacing is respectively (where, D = inside diameter of the shell)

A

$$\frac{{\text{D}}}{5}$$ and D

B

$$\frac{{\text{D}}}{2}$$ and 2D

C

$$\frac{{\text{D}}}{4}$$ and 2D

D

D and 2D

In a multipass shell and tube heat exchanger, the problem of differential expansion between the shell and tube passes is taken care of by using a

A

U-bend

B

Floating head tube sheet

C

Either A or B

D

Neither A nor B

In case of a multipass shell and tube heat exchanger, providing a baffle on the shell side __________ the heat transfer rate.

A

Increases

B

Decreases

C

Does not affect

D

May increase or decrease, depends on the type of baffle

Minimum recommended baffle spacing in a shell and tube heat exchanger is about (where, D = shell diameter)

A

0.2 D

B

0.5 D

C

0.66 D

D

0.80 D

Which is the earliest and most widely used shell that came with the UNIX system?

Related Questions