An insulated rigid tank having a 0.2 m3 volume initially contains air at 400 kPa and 313 K. The amount of paddle-wheel work done on the system is 200 kJ. Calculate the nearest value of entropy change

a. 0.66 kJ/K

b. 0.88 kJ/K

c. None

d. 0.44 kJ/K

e. 0.33 kJ/K

A refrigerator removes heat from a refrigerated space at -6°C and rejects it to an environment at 30°C. If the temperature in the cooled area is reduced to - 18°C, determine the minimum percentage increase in the work required for the same amount of energy from which the Carnot refrigerator is removed.

a. 53

b. 33

c. 93

d. 13

e. 73

A single stage double acting air compressor having a clearance of 4% takes in air at 14.2 Psia and 60 and compresses it to 200 Psia. If the weight of the air compressed per minute is 50 lbs. and n = 1.35, compute: a) The work required to compress the air per minute b) The piston displacement if the compressor operates at 100 RPM c) The volume of free air measured at 14.7 Psia atmospheric pressure.

Complete the following statements about the crystallinity in polymers by choosing the right answers in the [box].

Most thermoset polymers are [amorphous/crystalline] .

Some thermoplastic polymers are semi-crystalline, meaning they have both higher density  [amorphous/crystalline] regions and lower density  [amorphous/crystalline] regions.

In many semi-crystalline polymers, the polymer chains fold into [lamellae/spherulite] structures which can be part of a larger  [lamellae/spherulite] structure which is formed around a nucleation site.

In semi-crystalline polymers, the glass transition temperature is where there is an increase in the ability of the polymer chains to move in the  [amorphous/crystalline] regions. The melting point is where the  [amorphous/crystalline] regions turn into a liquid.

Explain in general in which area you would apply similarity concept along your career as
a mechanical engineer. How will it benefit you and your organisation.

A three-dimentional flow velocity can be measured by using various method. Please name
two devices that use a probe and two sophisticated devices without a probe usage for the
three-dimentional flow velocity measurement.

The terrace roof of a building at sea level is planned to have a rectangular floor area with dimensions of 10 m and 20 m. The prevailing wind speed in winter is u∞=25 km/h, and air temperature is assumed to be T∞=0°C. Considering that the outer surface temperature of the building is To=10°C, how should the building be positioned with respect to the prevailing wind direction to minimize the heat loss from the roof?

Stances that include stable or unstable equilibrium.Describe five stances used in sports and the reason for using those particular stances

A heat engine operates between a source and a sink. The source temperatures vary from 300 to 1000°C. Heat is supplied to the heat engine at a steady rate of 1200 kJ/min. Using Matlab or Excel (or other) software, study the effects of the temperatures of the heat source and the heat sink on the maximum power produced and the cycle thermal efficiency. Plot the power produced and the cycle efficiency against the source temperature for sink temperatures of 0°C, 25°C, and 50°C, and discuss the results.

Define the following questions

1. Carburisation is a heat treatment used for case hardening steels. Carbon is trapped on steel surface by:

2. Concentration gradient refers to

3. Interstitial diffusion is generally faster than diffusion by vacancy mode. This is because:

4 .Diffusion is the result of:

5 .As the temperature rises, the rate diffusion:

thank you

what is the main different between synchronous machines and asynchronous.Explain it

Explain the different regions of heat affected zone obtained in welding of Martensitic stainless steel (not mild steel)

Note: Kindly give the answer in details for Higher education assignment purpose.

A catrifugal pump is operating at the rotation rate of 750 rpm. Pump is working at the design condition. Water leaves the blade at 40^o from the radial direction. Water enters to blade at 80^o from tangential direction( offdesign condition). The inner and outher radius of the impeller is 12 cm and 18 cm respectivelly. The width of the impeller is 14 cm. Flow rate of the pump is 0.60 m³/s.

1. Draw the velocity triangles at inlet and outlet of the blade.

Determine;

     b) the blade angles, b₁ and b₂.

    c)Net head and power of the pump,

    d) Specific speed of the pump

Do not solve the problem without drawing the velocity triangles at inlet and outlet.

There is a heat pump that operates with R 134ª refrigerant, whose compressor has a power of 5 kW. The heat pump condenser is used to heat oil from a temperature of 0 degrees Celsius, up to a temperature of 20 ° C, so the condenser operates with a condensation temperature of 40 ° C. Furthermore, the evaporator operating with an evaporation temperature of 5 ° C, it is desired to use to air conditioning from a temperature of 35 ° C and a relative humidity of 50% to a final temperature of 20 ° C and a relative humidity of 60%
DECIDE.
1.1.-COP as a heat pump
1.2.-COP as refrigeration equipment.
1.3.-Electric power of heaters to achieve the required humidity, kW
1.4.-Oil flow, l / min, that can be heated.
1.5.-Air flow, m3 / h that can be cooled.
1.6.-Diagrams p-h,Psychometric and T-s of the process in the equipment.
1.7.-Diagram of how you would do the oil heating and air conditioning system.Psychometric diagram

¿What else do you need to solve the problem?, if something is missing just take a random value.

please explain methods that can be used for varying the speed of induction machine (min 4 method)