List the conditions to be met for a thermodynamic process to be accurately described as a steady state, steady flow process. Write down a mathematical expression for the First Law of Thermodynamics as applied to such a process, explaining clearly the notation and sign conventions used. A pumped domestic shower unit incorporates an electrical resistance heater to increase the temperature of liquid water before it is directed towards the shower head. The heater in a specific model draws 7.2 kW of electric power and operates in a steady state with an inlet water supply temperature of 5degrees celcius during cold weather. (A) What inlet water flow rate (in litres per minute) can be sustained if the outlet water temperature is to be 50degrees celcius at the exit from the heater? (B) What exit temperature (oC) would be achieved if this water flow rate were increased by 60%?
In: Mechanical Engineering
According to metal additive manufacturing, what are the variables impact the two quality issues below, explain in details how and why pressure, force, temperature and time affect them. a. surface finish. b. dimensional accuracy.
In: Mechanical Engineering
In no more than 300 words, describe the differences between a typical elastomeric engine mount and a typical hydramount. You should use diagrams, theory and mathematical models where appropriate to highlight the key differences and positives and negatives of both.
In: Mechanical Engineering
A model of an air ship is to be studied. The prototype is envisaged to be 8 m long with a diameter of 750 mm and the model is to be 300 mm long. What should the diameter of the model be? What should the diameter velocity in a wind tunnel be to simulate actual conditions? If the drag on the full model is found to be x N, what would the drag on the prototype be?
In: Mechanical Engineering
(Using Matlab)We are given data about a charity organization in table 1 Days 10 20 30 40 50 60 70 80 90 100 Donation 23 45 60 82 111 140 167 198 200 220 Table 1: Donation collection by the charity organization Assume that x corresponds to the independent variable. Compute linear, quadratic and cubic fit for the data using regression techniques and plot them on three different graphs, all on the same figure. Use an appropriate small interval to create your plots. Mark the original data with green circles. Give appropriate titles and labels for the graph. Explain in few sentences which model best represents the data and why? Now, use the best model to find the value of the donation collection for 25th day. Print this value.
In: Mechanical Engineering
According to the metal additive manufacturing process identify and explain the reason behind the key processing limits below. a.limits of the equipment used. b.limits of the material being processed.
In: Mechanical Engineering
A vehicle which is equipped with a 6 cylinder, 2000 cc spark ignition engine is cruising at an average speed of 150 km/h from Ankara to Istanbul on the highway. The mass of the vehicle with single driver is 1200 kg and its projected frontal area is 3 m2. The coefficient of rolling resistance is 0.015 and the discharge coefficient is 0.3. The distance between Istanbul and Ankara is approximately 450 km. Assuming an average brake specific fuel consumption of 250 g/hp-h, calculate how many liters of fuel will be used during this journey ( r fuel = 0.73 g/cc and ambient air density r a=1.2 kg/m3).
In: Mechanical Engineering
A certain crude oil shows the following ultimate analysis: C=87.1% and H2=12.9%. The volumetric analysis of the dry flue gas resulting from the combustion of this oil shows CO2=12%, O2=4.6%, CO=0%, and N2=83.4%
a. Theoretical Air-Fuel Ratio
b. Actual Air Fuel Ratio
c. Excess air in Percent
In: Mechanical Engineering
In: Mechanical Engineering
1- Abrasive wear is most common in situations in which:
a. Hard particles are caught between two contact surfaces
b. the hardness of one material is much higher than the other
c. Neither A or B
d. Both A and B
2- What material property is critical to predicting wear behavior?
a. buckling resistance
b. tensile strength
c. modulus
d. hardness
3-What is the general cause of corrosion of low carbon steel?
a. Stray electric currents (very small)
b. Using two-dissimilar metals together
c. Being in the presence of moisture or water
d. All the above
In: Mechanical Engineering
Specify 6 best practices for controller loop tuning. Outline the details for each of these practices. Provide details for each.
In: Mechanical Engineering
what is the heat treatment procces for the aircraft turbine blade ?with steps
In: Mechanical Engineering
Give AT LEAST 5 METHODS of priming pumps.. Show their illustrations and describe how each methods are used in priming pumps.
In: Mechanical Engineering
Over the last 50 years, the United States labor economy has changed from a manufacturing to service and technology focus. Other than the obvious changes, such as fewer mine tragedies and more carpal tunnel syndrome, what other trends in employment safety do you predict, and what is your evidence for that prediction? How should companies respond? How would you respond? Why?
In: Mechanical Engineering
Question 1
a) A cylindrical feedstock of length = 35.4 cm and diameter = 10 cm is subjected to turning using a high speed steel tool. For this tool, n and C values in the Taylor tool life equation are 0.125 and 70 m/min, respectively. The cost for hiring an operator and using the machine tool are $82 per hour. The tooling cost per edge of cutting is $5. Loading and unloading the part on to the machine takes about 4 min, and it takes about 2.5 minutes to change the tool. At a feed rate of 0.25 cm/rev, calculate:
(i) cutting speed for maximum production rate,
(ii) tool life [minutes], and
(iii) cost per unit and total cycle time of a produced part.
b) On a rectangular stock of aluminium alloy [tensile strength = 305 N/mm² and yield strength = 215 N/mm²] with dimensions of length = 320 mm and width = 30 mm, peripheral milling is performed on the top surface. The diameter of the carbide milling tool is 60 mm, with 8 teeth. The milling tool is centred along the workpiece width. At cutting speed of 80 m/min, chip load of 0.17 mm/tooth, and a depth of cut of 5 mm, calculate the following:
(i) the time to complete one machining one pass across the surface, and
(ii) the rate of maximum material removal during this cut.
Question 2
a) List and describe the five processes that cause wear at the interface of the tool and chip and the interface of tool and work in machining. What are the two major factors which enhance tool wear mechanisms? Explain in detail.
b) List and describe the three main processes that cause grinding wheel wear. Define Grinding Ratio and explain in detail, the relationship between grinding ratio, surface finish, and wheel speed using a plot.
Question 3
a) In an Electrochemical Machining process, the feedstock is made of an aluminium alloy (Ultimate Tensile Strength=572 MPa, Tensile Yield Strength=503 MPa). The desired time to machine a hole (?=10 mm) through a 20 mm-thick part is 2.1 min at a feed rate of 0.18 mm/s. What are:
(i) the efficiency of the process in %, and
(ii) the current requirement in amps to achieve this machining time target?
b) Describe in detail the process of circular sawing with the aid of a freehand sketch. What are the two major mechanisms by which circular sawing is achieved and what materials are commonly used as circular saws of each type?
In: Mechanical Engineering