How material properties, such as glass transition temp, conductivity, and crystallinity, change with elevating temperatures! Meanwhile, corrosion is another pressing issue in our daily life. What are the origin and underlying mechanisms? Why Metals oxidize so fast!? How do you extrude polymer into thin fibers for clothes, fences, and fibers? and how do your favorite sports connect with composite materials?

Air at 60oC and 1 atm enters a smooth tube having a diameter of 2 cm and length of 10 cm. The air velocity is 40 m/s: 1- What constant heat flux must be applied at the tube surface to result in an air temperature rise of 5oC? 2- What average wall temperature would be necessary for this case?

Answer: (1) qs = 11841W/m2    (2) Tw = 97oC

Liquid bismuth flows at a rate of 4.5 kg/s through a 5.0-cm-diameter stainless-steel tube. The bismuth enters at 415oC and is heated to 440oC as it passes through the tube. If a constant heat flux is maintained along the tube and the tube wall is at a temperature 20oC higher than the bismuth bulk temperature, calculate the length of tube required to effect the heat transfer. For liquid bismuth: ? = 1.34 ?10-3 kg/m· s Cp = 0.149 kJ/kg.oC k = 15.6 W/m. oC Pr = 0.013

Answer: L = 1.57 m

1. What are the Limits of the material being processed in the Fused Deposition Modeling (FDM), apart from using Thermoplastic only?

2. What are the Limits of the equipment being used in the Fused Deposition Modeling (FDM), apart from producing small parts only?

Explain why in welded components, residual compressive stresses are as detrimental as residual tensile stresses, but in unwelded components residual compressive stresses are beneficial.

A new type of bird capable of self-propulsion is designed in order to maximise its flying distance in the presence of aerodynamic drag. This new bird, having the initial mass of mo, generates thrust by ejecting 1% of its initial mass (0.01mo) with the velocity of 50m/s in the direction opposite to the bird’s instantaneous velocity relative to the bird every 0.1s (similar to how rockets generate thrust).

function [vx_f,vy_f,m_f] = mass_ejection(vx_i,vy_i,v_eb,m_i,m_e)

% Inputs:

% vx_i: Velocity component in x direction before ejection

% vy_i: Velocity component in y direction before ejection

% v_eb: Ejection velocity of the mass relative to the bird

% m_i : Mass of the bird before ejection

% m_e : Ejection mass

% Outputs: % vx_f: Velocity component in x direction after ejection

% vy_f: Velocity component in y direction after ejection

% m_f : Mass of the bird after ejection

(d) Using the function written incorporate the mass ejection mechanism into the existing model with drag (remember that you need to run this function every 0.1s and use the output to update the velocity and mass of the bird). Compute and plot the trajectory of the new bird and compare it with the trajectory of the original bird with the same initial conditions. On your plot, indicate with symbols where mass ejections happen. The bird is launched with the initial velocity of 10m/s at the angle of 50? from the horizontal. The initial mass of the bird, mo is 1kg. The release point of the bird is 2m directly above the base of slingshot and the base of slingshot can be considered as the origin (figure 5). The density of air is 1.2 kg/m3 and use CD = 1. The bird can be treated as a sphere with a radius of 0.15 m. on matlab

Explain the characteristics of different joints explain briefly ,with neat sketch. thanks you

1. Explain the differences between fixed and random factors in Design of Experiments (DoE).

2. Explain the three pillars of DoE.

3. What are the differences between replication and repetition?

4. In plastic injection molding, temperature, time in mold, and injection pressure each play an important role in determining the strength of the part. At MAR Inc., experimenters are studying the effects on part strength when the temperature is set at either 250o, 275o, or 300oF; the time in mold is either 5, 7, or 9 seconds; and the injection pressure is either 200, 250, or 300 psi. Create a table show the factors and their levels for this information.

5. For the information in problem 4, how many tests would be necessary to test every possible treatment (a full factorial experiment)?.

6. A team is currently working to redesign a compressor assembly cell. The team has several design changes that they want to test using design of experiments. They want to decrease the cell’s assembly and packing throughput time. Currently, it takes 45 minutes to assemble and pack a compressor. The team is considering three changes: Reduce current 36 inch conveyor width to either 18 inch or 24 inch; Install new parts presentation shelving, either flat surfaced or angled Line form: either straight or curved Implement the first four steps of the experiment design process in slide 15. Comment on how to interpret and verify the results

The particulars of a 20 TR R 22 food freezer are as follows:

Evaporator temperature – 30°C

Condenser temperature 40°C

Temperature of vapor leaving evaporator – 25°C

Subcooling of liquid with vapor in heat exchanger 5°C

Polytropic index of compressor 1.15

Superheating of suction vapor after passing through suction valve 15°C

Compressor clearance factor 0.05

Pressure drop in valves 0.2 bar suction

0.5 bar discharge

The compressor has 6 cylinders with bore equal to stroke. Its rpm is 1500, and mechanical efficiency is 0.75. Determine

(i) Mass flow rate of refrigerant.

(ii) Piston displacement of compressor.

(iii) Cylinder diameter.

(iv) Motor horse power.

(v) Cooling requirement of compressor in kW.

GD&T

Discuss following:

1) Form deviations

2) Flatness, straightness, and circularity tolerances

3) How bonus tolreances affect part processing

4) Correctly specifying form tolerances

GD&T

what is good practice when you are dimensioning drawing?

Discuss followings: write 150 words minimum

1) general symbols and abbreviations

2) geometric tolerancing symbols

3) feature control frams

4) datum identification

5) basic dimensions

6) the 14 maior gd&t symbols

Consider the following cookie making process at a bakery store. 1) Alice puts all the ingredients in a mixing bowl and mix them. 2) Bob spoons the cookie dough onto tray and puts tray into oven. 3) Cookies are baked in oven. Note: The oven is already programed to bake cookie for 20 minutes; Bob quickly pushes the Start button when after he puts tray into oven, and there is not any other oven operation needed during baking. 4) Cathy takes the cookies out of tray and pack them in to a bag. Answer question a) to f).

a) The task time of the cooking making process are as follows. Fill out the relevant resource for each task in the table.

Tasks Task Time Resource Relevant Resource

Put ingredients in bowl and mix them 5 min

Spoon dough to tray and put into oven 3 min

Bake cookies 20 min

Take cookie out of tray and pack to bag 4 min

b) Draw a process flow diagram of the cooking making process. Note: Put buffer between each two activities; the diagram should include the task description and resource.

c) Compute the capacity of each relevant resource.

d) Suppose there are infinite amount of ingredients available and there is an infinite demand of cookies during the work hours for the cookie store. Also suppose there is no ingredients waste during the process. Identify the bottleneck of the process and Calculate the capacity of the cookie making process. Hint: identify the bottleneck of the process.

e) Calculate the cycle time of the cookie making process.

f) Calculate the flow time of the cooking making process

In 1908 Jenry Ford produced the first affordable automobile using his assembly line method. At the time, the assembly line was a new and emerging technology and is now the essential element of most manufacturing processes. You probably can easily identify the benefits achieved by the assembly line. However, there were some ethical consequences to its development and implementation. Discuss what you believe to be ethical consequences of the assembly line. Do those consequences still apply in today's manufacturing environment with the use of robots? what should manufacturers do to alleviate these consequences?