At 300ºC the diffusion coefficient and activation energy for Cu in Si are

D(300ºC) = 7.8 x 10-11 m2/s

Qd = 41.5 kJ/mol

R = 8.314 J/mol -K

What is the diffusion coefficient at 684ºC (in 10-11 m2/s )

Explain the reason for the failure of the Titanic in terms of Materials Science.

Hypothetical metals A and B form an isomorphous binary phase diagram. Assume that you need to increase the strength of an A-B alloy. Can you achieve this with the help of precipitation hardening? Explain.

1) Somewhere along the flow stream in a siphon the pressure is less than atmospheric pressure.

True

False

2)it is reasonable to expect that the top speed of the boat will approximately double if a 9 Hp boat motor is replaced with an 18 Hp boat motor, All else being equal,

True

False

3)In a steady-state flow, it is not possible for fluid parcels of fixed identity to accelerate.

True

False

1.

Given the angle of rotation is small and the materials remain linear elastic, which statement below is incorrect for the torsional behavior of a long straight circular shaft:

2.

The unit for a shaft’s polar moment of inertia J is:

3.

Provided that the bending formation of a straight member is small and within elastic range. Which of the following statements is incorrect? (select all that apply)

4.

Which of the following statements is correct for bending of a straight member?

5.

Which of the following statements is true? The flexure formula for a straight member can be applied only when: (select all that apply)

design a method for synthesis of titanium based nanoparticles from Catharanthus roseus and mention name of few techniques for its characterization and discuss in detail about the application of designed nanoparticles for controlled drug delievery?

A cylindrical pressure vessel with flat ends of length 6 ft and inner diameter of 35 in. is subjected to an internal gauge pressure of 150 psi. Neglect the end effects and the mass of ends of the pressure vessel in your design. Take the factor of safety as 1.95:

Draw diagrams showing the components of a ball mill and movement of charge inside the mill. Label the important features.

An ideal Otto cycle has a compression ratio of 8.5 At the beginning of the compression process, air is at 98 kPa and 27∘C, If the Tmax cannot exceed 2300K and 3e-5 kg of. assuming constant specific heats at ambient temperature, determine (a) the pressure and temperature at the end of each process. (b) the net work output, (c) the thermal efficiency, and (d) the mean effective pressure for the cycle.

1. If the specific weight of a liquid is 8.1 kN/m_­­­­³, what is its density?

2. If the specific volume of a gas is 0.70 m³/kg, what is its specific weight in N/m³?

3. If a certain liquid weighs 8600 N/m³, what are the values of its density, specific volume, and specific gravity relative to water at 4⁰C?

4. At a depth of 12 m of a solvent the pressure at the bottom of the covered storage tank due to the solvent was 350 kPa. Calculate density of the solvent.

5. At what depth within a salt water solution will the gauge pressure be equal to three times the atmospheric pressure?                    
   ρ salt water=1100 kg/m³                                             atmospheric pressure =101,325 Pa

6. How large must a heating duct be if air moving 3 m/s along it can replenish the air in a room of 300 m³ volume every 15 minutes? Assume the air’s density remains constant.

8. Water is flowing in a fire hose with a velocity of 1.0 m/s and a pressure of 200000 Pa. At the nozzle the pressure decreases to atmospheric pressure (101300 Pa), there is no change in height. Use the Bernoulli equation to calculate the velocity of the water exiting the nozzle.   

10. At Petrojam, fuel is flowing through a pipe at a velocity of 1 m/s and a pressure of 101300 Pa. They need the fuel to be at a pressure of 3 atm (202600 Pa) on a lower level. How far must the pipe drop in height in order to achieve this pressure if the velocity does not change? The density of the fuel is 789 kg/m3.

UNIT EIGHT - ANSWER EACH QUESTION

1.  Explain the difference between coating and cladding

2. Describe the two main methods of painting: dipping and spraying (manual, automatic or electrostatic).
a) State the characteristic of each method.
b) Identify materials suitable for each method.

3. Describe the electroplating process.
a) List typical plating materials and give reasons for their use.

4. Explain the process of anodizing and state typical applications.

5. Classify vapour deposition processes into physical vapour deposition (PVD) and chemical vapour deposition (CVD).
a) Describe the principle of each process.
b) Identify applications of each process.

6. Recognize the importance of thermal spraying.
a) Explain the principle of thermal spraying.
b) Identify typical thermal spraying processes according to the technology used to melt the coating material.:- oxyfuel flame, electric arc and plasma arc.

An engine is coupled to a rotating drum by a friction clutch which has a single plate faced on each side with a ring of friction material. The inner and outer diameters of the friction faces are 224 mm and 300 mm respectively. The coefficient of friction is 0,3. Other data available are: axial pressure on plate = 1350 N ; engine torque is constant at 40,7 N.m inertia of engine equivalent to a flywheel of mass 20,7 kg; and radius of gyration k=0.305 m. Drum mass is 54,5 kg; radius of gyration k=0,38 m; total friction torque in bearings = 6,8 N.m; and the clutch is engaged when engine speed is 500 r/min and the drum is at rest.

Assuming uniform wear conditions, find the engine speed at which the clutch ceases slipping and the total time for the drum to reach 500 r/min.

. Air enters the compressor of an ideal gas refrigeration cycle at 7oC and 40 kPa and the turbine at 37oC and 170 kPa. The mass flow rate of air through the cycle is 0.3 kg/sec. Assuming variable specific heats for air, determine (a) the rate of refrigeration, (b) the net power input, and (c) the coefficient of performance. Also, draw the T-s diagram of the gas refrigeration cycle.