Two samples of a low hardness steel were tested using a Rockwell C hardness tester and the Rockwell B scale at the same lab on the same day . The difference between the average hardness of the two samples was 0.5 Rockwell C. Do you think there is a significant difference in the hardness? Justify your answer. Hint: Use the specification!!

Below is a model response solution. Rewrite this solution in one line using a correct notation that includes Heaviside functions.

x(t) = e?2t sin(3.46t) t < 3s

x(t) = e?2t sin(3.46t) + 0.2e?2(t?3) sin(3.46(t ? 3)) 3s ? t < 5s

x(t) = e?2t sin(3.46t) + 0.2e?2(t?3) sin(3.46(t ? 3))+1 + 1 e?2(t?5)cos(3.46(t?5)?0.52) t?5s 16 13.86

An austenitized 70 mm diameter 4340 steel bar is quenched in agitated H2O. Predict what the Rockwell C hardness of the bar will be at (a) its surface, (b) 3/4-R, (c) midway between its surface and center and (d) at its center

(a) S: _53_____                      (b) 3/4R: __52_____ (c) MR: __52_____      (d)

C: __51____

Please show work

Assuming the elastic solution for the stresses near a crack tip is valid in the case of small-scale yielding, determine r_p(q) for Mode I and Mode II  in plane stress and plane strain. Plot a nondimensional r_p(q), ( r_p/ r_p(Irwin)) in the vicinity of the crack tip for several different values of Poisson's ratio.

For an ideal vapor-compression heat pump cycle, refrigerant 134a is used to provide 35 kW of heat to a building. Saturated vapor enters the compressor at 1.6 bar and saturated liquid exits the condenser which operates at 8 bar. What is (a) the mass flow rate of the refrigerant, and (b) the COP?

Thermodynamics

1. The answer is -12.31 can someone please explain how we get that.

A pump steadily delivers 9.7 kg/s of water at the conditions given below. Calculate the pump power (hp).

The rate of heat transfer from the pump to the surroundings is Q = 1.7 kW.

There are no changes in kinetic or potential energy.

Pump Inlet Temperature = 50^oC

Pump Inlet Pressure = 115 kPa

Pump Exit Temperature = 50^oC

Pump Exit Pressure = 877 kPa

2.

A pump steadily delivers 9.7 kg/s of water at the conditions given below. Calculate the pump power (hp).

The rate of heat transfer from the pump to the surroundings is Q = 1.7 kW.

There are no changes in kinetic or potential energy.

Pump Inlet Temperature = 50^oC

Pump Inlet Pressure = 115 kPa

Pump Exit Temperature = 50^oC

Pump Exit Pressure = 877 kPa

3.

can someone please explain how we get the answer -40.45

A pump steadily delivers 7.89 kg/s of water at the conditions given below. Calculate the pump power (hp).

The rate of heat transfer from the pump to the surroundings is Q = 1.42 kW.

There are no changes in kinetic or potential energy.

Pump Inlet Temperature = 50^oC

Pump Inlet Pressure = 1.05 MPa

Pump Exit Temperature = 50^oC

Pump Exit Pressure = 4.65 MPa

which type of gear material used for making a gear using in jurk?

which grade of steele example steel 304,316, 321,202, is suitable and easy drilled? PLZ give wright answer

1) A pump steadily delivers 15.9 kg/s of water at the conditions given below. Calculate the pump power (kW).

There is no heat transfer from the pump to the surroundings (i.e., adiabatic conditions).

Pump Inlet Temperature = 20^oC

Pump Inlet Pressure = 196 kPa

Pump Inlet Diameter = 10 cm

Pump Inlet Elevation = 22.7 m

Pump Exit Temperature = 20^oC

Pump Exit Pressure = 400 kPa

Pump Exit Diameter = 10 cm

Pump Exit Elevation = 45.4 m

2) A pump steadily delivers 16.3 kg/s of water at the conditions given below. Calculate the pump power (kW).

There is no heat transfer from the pump to the surroundings (i.e., adiabatic conditions).

Pump Inlet Temperature = 20^oC

Pump Inlet Pressure = 107 kPa

Pump Inlet Diameter = 11 cm

Pump Inlet Elevation = 20.1 m

Pump Exit Temperature = 20^oC

Pump Exit Pressure = 380 kPa

Pump Exit Diameter = 4.2 cm

Pump Exit Elevation = 44.9 m

It is desired to air-condition a small one-room store located on the first floor of a building several stories in height. The store is 20' wide and 40' deep, and the ceiling height is 12'.The front wall, which faces north, may be condidered as 100% glass. The partitions between this store and the stores on either side are 4" cinder tile, platered on both sides; and the rear wall, which contains 40 sq ft of glass, is of 4" brickbacked by 8" concrete blocks with furred metal lath and plaster on the inside surface. The floor construction consists of a 6" concrete slab with 1/8" asphalt tile flooring laid directly on the conconcrete. There is no ceiling in the basement. The store ceiling constructin consists of a 3" concrete slab with a suspended metal-lath and plaster ceiling below the supporting steel joist, and a double wood floor on sleepers above the slab. The store is to be kept at 80F and 50% relative humidity when the outside temperature is 95F and the relative humidity is 50%. The stores on either side are not airconditioned, nor are the offices on the floor above. The temperature in the basement may be assumed to be 7 1/2 deg warmer than the store. Assume that there will be an average of 20 persons in the store and that about 2,000 watts of fluorescent lighting will be used.

What are the coefficients of heat transmission for walls, ceiling, floor, and partitions?

Calculate the sensible heat gain of the store described . Do not include infiltration.

For the same store, find the number of pounds of fresh air needed per minute if 75% of the air is recirculated and 25% is fresh air.

Compute the number of tons of refrigeration required to air-condition the store.

Air enters a nozzle steadily at P1=650kPa and T1=125°C at a velocity of 12m/s and leaves at 150m/s with a pressure of P2=110 kPa and temperature of T2=78°C. If the inlet are of the nozzle is 85cm^2, determine (a) Mass flow rate of air in the nozzle and (b) Exit diameter of nozzle.

A 16​-lb weight stretches a spring 16 ft. The​ spring-mass system is in a medium with a damping constant of 1.5 ​lb-sec/ft, and an external force given by

f (t)= 3+e^-3t ​(in pounds) is being applied. What is the solution function describing the position of the mass at any time of the mass is released from

1ft below the equilibrium position with an initial velocity of 2 ​ft/sec downward?

3) Air flows steadily at the rate of 0.4 kg/s through an air compressor, entering at 6 m/s with a pressure of 1 bar and a specific volume of 0.85 m3/kg, and leaving at 4.5 m/s with

      a pressure of 6.9 bar and a specific volume of 0.16 m3/kg. The internal energy of air leaving is 88 kJ/kg greater than that of the air entering. Cooling water in a jacket surrounding the cylinder absorbs heat from the air at the rate of 59 kJ/s. (i) Calculate the power required to drive the compressor and (ii) the inlet and outlet pipe cross-sectional areas.

4) Steam enters a turbine at 20 m/s and specific

           enthalpy of 3000 kJ/kg and leaves the turbine at

           40 m/s and specific enthalpy of 2500 kJ/kg. Heat

           lost to the surroundings is 25 kJ/kg of steam as the

           steam passes through the turbine.

5) A turbine, operating under steady-flow conditions, receives 5000 kg of steam per hour. The steam enters the turbine at a velocity of 3000 m/min, an elevation of 5 m and a specific enthalpy of 2787 kJ/kg. It leaves the turbine at a velocity of 6000 m/min, an elevation of 1 m and a specific enthalpy of 2259 kJ/kg. Heat losses from the turbine to the surroundings amount to 16736 kJ/h. Determine the power output of the turbine.

           If the steam flow rate is 360000 kg/h, determine the

           output from the turbine in MW.

6) A refrigerator operates on reversed Carnot cycle.

    Determine the power required to drive refrigerator

    between temperatures of 42oC and 4oC if heat at the

    rate of 2 kJ/s is extracted from the low temperature

    region.

7) In a winter season when outside temperature is

     –1oC, the inside of house is to be maintained at

      25oC. Estimate the minimum power required to run

      the heat pump of maintaining the temperature.

      Assume heating load as 125 MJ/h.

8) What would be maximum efficiency of engine that

     can be had between the temperatures of 1150oC

      and 27oC ?

9)A heat engine is supplied with 278 kJ/s of heat at a constant fixed temperature of 283°C and the heat rejection takes place at 5°C. The following results were reported :

(i) 208 kJ/s are rejected, (ii) 139 kJ/s are rejected, (ii) 70 kJ/s are rejected.

    Classify which of the results report a reversible cycle or irreversible cycle or impossible results.

10) An air-standard Otto cycle has a compression ratio of 9. At the beginning of the compression process, the temperature is 20°C, and the pressure is 100 kPa. The heat added is 500 kJ/kg. Determine the cycle efficiency, work output, and the heat rejected.

11)An air-standard Otto cycle operates with a minimum temperature of 300 K and a maximum temperature of 1700 K. The compression ratio of the cycle is 7. At the beginning of the compression process, the pressure is 105 kPa. Calculate P, V, and T at each point in the cycle, the mean effective pressure, and the thermal efficiency of the cycle.

12)An air-standard Diesel cycle has a compression ratio of 22

    and a cut-off ratio of 2.2. Determine the thermal efficiency of

    the cycle.

13)An air-standard Diesel engine has 1000 kJ/kg added as heat.

    At the beginning of the compression, the temperature is

    20°C, and the pressure is 150 kPa. If the compression ratio is

    20, determine the maximum pressure and temperature in

    the cycle.

14)An ideal Stirling engine using air as the working fluid

     operates between temperature limits of 300 and 2000 K.

     Determine the thermal efficiency of the cycle.

15) Consider an ideal Ericsson cycle with air as the working

     fluid executed in a steady-flow system. Air is at 270C and

     120 kPa at the beginning of the isothermal compression

     process, during which 150 kJ/kg of heat is rejected. Heat

     transfer to air occurs at 1200 K. Determine the thermal

     efficiency of the cycle and net work output per unit mass of

     air.

An adiabatic air compressor with inlet conditions of 100 kPa, 27 C and an exit pressure of 500 kPa has an inlet volume flow rate of 5 m3/s and operates in steady flow. Calculate the minimum power required to drive the compressor.

1. Genichi Taguchi defined the taguchi loss Function: Explain what the Taguchi Loss Function means for both the consumer and Manufacturer

2. Boothroyd Dewhurst Manual Assembly: What do alpha a beta define?

3. Draw a FAST diagram for a manual toothbrush.

4. Assuming you have your favorite coffee beans ground and you have a coffee type drip coffee maker. List the steps and draw a Process Flow Diagram for brewing a pot of coffee.