5. Design a cast iron flywheel for a four stroke cycle engine to develop 110 kW at 150 r.p.m. The work
done in the power stroke is 1.3 times the average work done during the whole cycle. Take the mean
diameter of the flywheel as 3 metres. The total fluctuation of speed is limited to 5 per cent of the mean
speed. The material density is 7250 kg / m3. The permissible shear stress for the shaft material is
40 MPa and flexural stress for the arms of the flywheel is 20 MPa.

A small water droplet

A flat plates surface tempertures are initially at 120 deg C and 60 deg C with one surfaces temperature being lower due to air at 20 deg C flowing over it with a velocity of 2m/s having a heat transfer coefficient of 30 W/m ^2K. The themal conductivities of the sheet metal and air are 35 W/m K. and 0.0262 W/mK. respectively.

Without following the problem solving guide answer the following question providing detaied justifications:

A. What are the modes of heat transfer?

B. Is this a time dependent or steady state problem? Why or why not?

C. The themal conductivities in the sheet metal and air are significantly different. Recalling the definition of thermal conductivity, What can you conclude about the materials abilitys to transfer heat?

D. How would the heat transfer in the system differ if the cooling was through natural convection? Explain your reasoning.

E. Draw a schematic of the energy flow?

السؤال 27

1. The water flux of RO membranes ______ as water viscosity lowers.

   		Increases
   		Decreases
   		Alters
   		Fluctuates

السؤال 28

1. RO membranes are made of _______

   		Plastic
   		Cotton
   		Silk
   		Polymer

السؤال 29

1. A reverse osmosis membrane is a semi-permeable membrane that allows the passage of _________

   		Water
   		Dissolved salts
   		Organics
   		Bacteria

A refrigeration cycle absorbs 20,000 kJ/h of heat from a space maintained at -45^oC and rejects heat to the surrounding air at 30^oC.
i. Determine the actual power input to the refrigeration cycle if the coefficient of performance (COP) of the refrigeration cycle is 25% of that of a reversible refrigerating cycle operating between the same two temperature reservoirs (kW).
ii. Determine the minimum work input to the refrigeration cycle (kW).
iii. Will the heat rejected to the surrounding by the actual refrigeration be greater, smaller or the same as the heat rejected to the surrounding by the reversible refrigeration cycle?

Newton's second law of motion can always be used to derive the equations of motion of a vibrating system

At 180°C the heat of vaporization, AvapH of a certain liquid is 14.4 kJ mol'1 . The molar volumes of the liquid and the vapour at the boiling point are 115 cm3 mol'1 and 14.5 dm3 mol' 1 , respectively. Estimate the change in the boiling point of the liquid at 180°C per bar change in atmospheric pressure, dT/dp using the Clayperon equation. Briefly discuss the physical significance of the sign of dT/dp .

Hibbeler said in Engineering Mechanics Statics page 167 (14^th Edition):

"Notice that F_R is independent of the location of point O since it's simply a summation of the forces"

What I want to ask, It's known that a couple moment is a free vector and it can be moved arbitrary to any point on the body but how can I insist the same concept for Resultant Force, although I can't assure that point O is on the line of the action of F_R

In different words, how can I move F_R freely while not the Principle of Transmissibility nor free vector is applied to it.

A hot silver plate is having its upper surface cooled by air forced convection of 15 °C with heat transfer coefficient of 220 W/m.K. The 10-cm thick plate (mass density ρ=8530 kg/m3, Cp=380J/kg.K, k=110 W/m.K, and α=33.9×10-6 m2/s) has a uniform initial temperature of 650 °C, and the bottom surface of the plate is insulated.

(a) calculate the Bi number and determine whether the lumped capacitance method can be used. (2 points)

(b) Determine the temperature at the center plane of the plate after 3 minutes of cooling. Solve this problem using the analytical one-term approximation method. (Hint: use table 5.1 in the lecture slides) (8 points)

3. (a) Among thin-film and emerging photovoltaic technologies, explain two photovoltaic cells you understand well, in terms of working principle, structure, materials used, fabrication techniques, advantages, and disadvantages.

(b) Assume you are about to start a business in photovoltaic technologies. Based on what you have studied in this course; what type of photovoltaic cell business would you like to run? Explain the reasons.

The air, which has a temperature of 120 ° C, flows over a plate with a length of 1.2 m and a constant temperature of 30 ° C across the surface, and its speed flows at a speed of 2 m / s. According to this,
a.) Calculate the speed and temperature boundary layer thickness at the end of the plate.
b.) Find the local heat transfer coefficient and heat flux at the end of the plate.
c.) Find the average heat transfer coefficient and heat flux at the end of the plate.
(Properties of the air will be taken from the table)

all informations are given

Engineering Standards and Codes of Practice

a) With reference to the Engineers Australia Guidelines on Professional Conduct (part of their Code of Ethics), please write, in your own words, a concise summary of the requirements for competent practice

See Australia Guidelines on Professional Conduct below:

Engineers Australia

Our Code of Ethics

The Guidelines on Professional Conduct

The Guidelines on Professional Conduct provide a framework for members of Engineers Australia to use when exercising their judgment in the practice of engineering. The Guidelines are not intended to be, nor should they be interpreted as, a full or exhaustive list of the situations and circumstances which may comprise compliance and non-compliance with the Code of Ethics. If called upon to do so, members are expected to justify any departure from both the provisions and spirit of the Code. Ethical engineering practice requires judgment, interpretation and balanced decision-making in context. Engineers Australia recognises that, while our ethical values and principles are enduring, standards of acceptable conduct are not permanently fixed. Community standards and the requirements and aspirations of engineering practice will develop and change over time. Within limits, what constitutes acceptable conduct may also depend on the nature of individual circumstances. Allegations of non-compliance will be evaluated on a case-by-case basis and administered in accordance with Engineers Australia’s General Regulations 2013.

1. DEMONSTRATE INTEGRITY 1.1 Act on the basis of a well-informed conscience a) be discerning and do what you think is right b) act impartially and objectively c) act appropriately, and in a professional manner, when you perceive something to be wrong d) give due weight to all legal, contractual and employment obligations 1.2 Be honest and trustworthy a) accept, as well as give, honest and fair criticism b) be prepared to explain your work and reasoning c) give proper credit to those to whom proper credit is due d) in managing perceived conflicts of interest, ensure that those conflicts are disclosed to relevant parties e) respect confidentiality obligations, express or implied f) do not engage in fraudulent, corrupt, or criminal conduct 1.3 Respect the dignity of all persons a) treat others with courtesy and without discrimination or harassment b) apply knowledge and skills without bias in respect of race, religion, gender, age, sexual orientation, marital or family status, national origin, or mental or physical handicaps

2. PRACTISE COMPETENTLY 2.1 Maintain and develop knowledge and skills a) continue to develop relevant knowledge and expertise b) act in a careful and diligent manner c) seek peer review d) support the ongoing development of others 2.2 Represent areas of competence objectively a) practise within areas of competence b) neither falsify nor misrepresent qualifications, grades of membership, experience or prior responsibilities 2.3 Act on the basis of adequate knowledge a) practise in accordance with legal and statutory requirements, and with the commonly accepted standards of the day b) inform employers or clients if a task requires qualifications and experience outside your areas of competence

3. EXERCISE LEADERSHIP 3.1 Uphold the reputation and trustworthiness of the practice of engineering a) advocate and support the extension of ethical practice b) engage responsibly in public debate and deliberation 3.2 Support and encourage diversity a) select, and provide opportunities for, all engineering practitioners on the basis of merit b) promote diversity in engineering leadership 3.3 Communicate honestly and effectively, taking into account the reliance of others on engineering expertise a) provide clear and timely communications on issues such as engineering services, costs, outcomes and risks

4. PROMOTE SUSTAINABILITY 4.1 Engage responsibly with the community and other stakeholders a) be sensitive to public concerns b) inform employers or clients of the likely consequences of proposed activities on the community and the environment c) promote the involvement of all stakeholders and the community in decisions and processes that may impact upon them and the environment 4.2 Practise engineering to foster the health, safety and wellbeing of the community and the environment a) incorporate social, cultural, health, safety, environmental and economic considerations into the engineering task 4.3 Balance the needs of the present with the needs of future generations a) in identifying sustainable outcomes consider all options in terms of their economic, environmental and social consequences b) aim to deliver outcomes that do not compromise the ability of future life to enjoy the same or better environment, health, wellbeing and safety as currently enjoyed

Our Code of Ethics

As engineering practitioners, we use our knowledge and skills for the benefit of the community to create engineering solutions for a sustainable future. In doing so, we strive to serve the community ahead of other personal or sectional interests. Our Code of Ethics defines the values and principles that shape the decisions we make in engineering practice. The related Guidelines on Professional Conduct provide a framework for members of Engineers Australia to use when exercising their judgment in the practice of engineering. As members of Engineers Australia, we commit to practise in accordance with the Code of Ethics and accept that we will be held accountable for our conduct under Engineers Australia’s General Regulations 2013. In the course of engineering practice we will:

1. DEMONSTRATE INTEGRITY 1.1 Act on the basis of a wellinformed conscience 1.2 Be honest and trustworthy 1.3 Respect the dignity of all persons

2. PRACTISE COMPETENTLY 2.1 Maintain and develop knowledge and skills 2.2 Represent areas of competence objectively 2.3 Act on the basis of adequate knowledge

3. EXERCISE LEADERSHIP 3.1 Uphold the reputation and trustworthiness of the practice of engineering 3.2 Support and encourage diversity 3.3 Communicate honestly and effectively, taking into account the reliance of others on engineering expertise

4. PROMOTE SUSTAINABILITY 4.1 Engage responsibly with the community and other stakeholders 4.2 Practise engineering to foster the health, safety and wellbeing of the community and the environment 4.3 Balance the needs of the present with the needs of future generations

0.5 kg of air at 30 bar and 350 °C is allowed to expand reversibly in a cylinder behind a piston in such a way that the temperature remains constant to a pressure of 0.75 bar. Based on the law pv1.05= constant, the air is then compressed until the pressure is 10 bar. Assuming air to be a perfect gas, determine the:

a) net entropy change,
b) net heat flow,
c)net work energy transfer and sketch the processes on a T-s diagram, indicating the area, which represents the heat flow.