A commercial refrigerator with refrigerant 134a as the working fluid is used to keep the refrigerated space at TL = -35°C by rejecting waste heat to cooling water that enters the condenser at 18°C at a rate of 0.25 kg/s and leaves at 26°C. The refrigerant enters the condenser at 1.2 MPa and 50°C and leaves at the same pressure and 41.3°C. If the compressor consumes 3.3 kW of power, determine (a) the mass flow rate of the refrigerant, (b) the refrigeration load, (c) the COP, and (d) the minimum power input to the compressor for the same refrigeration load (e) find out the volume flow rate of refrigerant at the inlet of the condenser in L/min. Assume Th = 18 oC.

Al-Amin Stall is already doing their business since 2017 besides the main road to Balik Pulau, Pulau Pinang. This famous stall sells Thai fusion food or also known as “Masakan Panas” among the local people such as Nasi Goreng Kampung, Nasi Goreng Pattaya, Tomyam soup, etc. Besides that, they also served western food such as chicken grill, chicken chop, mushroom soup, lamb grill and fish and chips.

The main problem with this stall is although the stall is famous in Balik Pulau, the business is not in good condition. They always record a small amount of loss at the end of the business month for almost 1.5 years. After visiting the stall, it looks like they didn’t have any specific system to record and track raw material that comes in and out. Besides that, the employee can eat what they want when they work; and not to forget the whole family members make this stall as their second home kitchen where they go and eat anytime they want without paying to the business. They only hire two people to work with them in the kitchen to cook and prepared drinks for the customer.

Besides that, some of the customer complaint that their service too slow. They have to wait quite some time to get their order. On the other hand, their kitchen is crowded with raw material supply where only two people can work there at one time, but the kitchen size is 20 feet x 10 feet. When looking at the dining area, their chairs and table are not ergonomically sound and some of them already broken and no safety at all.

When COVID-19 hit Malaysia, Malaysian government have implemented the Movement Restriction Order (MRO); which gives a massive impact to the stall owner income. The owner thinks it is now the correct time to ask someone who has a background of industrial engineering (which is you) to help him to plan what to do to boost up its business.

Tasks:

Based on group of maximum 5 person, kindly help Al-Amin stall owner to strategized what to do in detail and explain to him why he must do that according to the knowledge you had learn in industrial engineering subject.

I need a Cover Letter for applying job in boeing ?

A flat plate’s surface temperatures are initially at 120 oC and 60 oC with one surface’s temperature being lower due to air at 20 oC flowing over it with a velocity of 2m/s having a heat transfer coefficient of 30 W/m2×K. The thermal conductivities of the sheet metal and air are 35 W/m×K and 0.0262 W/m×K, respectively

a. What are the modes of heat transfer?

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

c. Is this a 1-D, 2-D or 3-D problem? Why or why not?

d. The thermal conductivities in the sheet metal and air are significantly different. Recalling the definition

of thermal conductivity, what can you conclude about the materials’ abilities to transfer heat?

e.How would the heat transfer in the system differ if the cooling was through natural convection?

Explain your reasoning.

f. Draw a schematic of the energy flow.

g.Write down the energy balances to determine the temperature gradient at the top surface of the plate.

Do not solve.

Hydrogen enters the turbine of an Ericsson cycle at 1280 K, 15 bar with a mass flow rate of 1 kg/s. At the inlet to the compressor the condition is 300 K and 1.5 bar.


Assuming the ideal gas model and ignoring kinetic and potential energy effects, determine:

(a) the net power developed, in kW.

(b) the percent thermal efficiency.

(c) the back work ratio.

The figure below provides the T–s diagram of a Carnot heat pump cycle for which the substance is ammonia, where x₃ = 70%.

Determine the net work input required, in kJ, for 50 cycles of operation and 0.1 kg of substance.
Note that work is positive going into the heat pump.

A mass flow rate of 2 kg/s of steam is expanded in an adiabatic turbine with an isentropic efficiency of 0.92. The steam enters at 3 MPa and 400 C and leaves at 30 kPa. Determine how much power the turbine is producing. Express your result in kW.

(Sol: 1649 kW)

TAKE YZ = 34

A recent public relations fiasco has intensified demand for engine testing for a particular OEM of
agricultural machinery. Historically, these engines are estimated to have a constant failure rate of 7
failures per 10000 + YZ (ten thousand + YZ) hours.
A local TV station is testing the engines under two different trials (25 hours and 100 hours)
What is the reliability of a single engine after 25 hours AND 100 hours?

What is the probability of no failed engines, a single failed engine, and more than one failed
engine, if the engines are tested in batches of 5 engines? Use the Poisson method and fill in the table on
the next page, for both the 25 hour test and the 100 hour test. (show one sample calculation below)

0 failed 1 failed >1 failed TOTAL
100.00 % (25 hours)
100.00 % (100 hours)
Two separate third party labs are also testing the engine but using some different criteria.
Number of engines tested Number Failed
Lab 1 220+YZ 43
Lab 2 127 25
Formulate the hypothesis comparing the two labs, using the Z test for binomial trials (difference in
proportions). What significance did you find?

The fit Φ 50M7/n6 is

Given your registration ID as: 0 - AB - XYZV ( 0 -17-7625) If the position of a particle moving in a straight line is given as function of time by: s ( t ) = ( t − x ) ( t − y ) ( t − z )

1- Plot the s - t curve, v - t curve and a - t curve

2- Find the average velocity and average speed through a time interval t =max(X,Y,Z ) .

3- Plot the path of the particle.

4- Find the max instantaneous velocity.

5- The speed of the particle at the beginning of motion

A 1-cm diameter UO2 fuel rod with zirconium clad of thickness 0.025 cm develops 16.4 kW/m. The coolant heat transfer coefficient is 7000 W/m2 oC, and the fluid saturation temperature is 280 oC. Assume any missing data, and write all assumptions

Questions

1) Write the 1D steady state conduction equation of the fuel rod and the clad,

2) Find the thermal conductivity of the fuel and the clad,

3) Specify the boundary conditions,

4) Write the solution of the equation for the fuel and the clad,

5) Compute the heat flux at the surface of the fuel,

6) What is the temperature at the center of the fuel rod?

7) What is the temperature at the surface of the fuel rod?

8) What is the temperature at the surface of the clad?

9) How much the maximum and minimum temperatures and where is each?

10) What is the total rate of heat (Watts) at the fuel-clad interface and coolant-clad interface?

Air enters the compressor of a regenerative air-standard Brayton cycle with a volumetric flow rate of 20 m³/s at 0.8 bar, 280 K. The compressor pressure ratio is 20, and the maximum cycle temperature is 1950 K. For the compressor, the isentropic efficiency is 92% and for the turbine the isentropic efficiency is 95%.


For a regenerator effectiveness of 86%, determine:

(a) the net power developed, in MW.

(b) the rate of heat addition in the combustor, in MW.

(c) the percent thermal efficiency of the cycle.

1) A gas turbine operates on an ideal Joule cycle using air (γ = 1.4; R = 0.287 kJ/kg K) as working fluid. Air enters the compressor at temperature of 27◦C and pressure of 1.25 bar and is compressed to 7.6 bar. When the maximum cycle temperature is limited to 800 oC, calculate,

(i) the thermal efficiency and work ratio of the cycle

(ii) the temperature of air exiting the turbine and the change in specific entropy of turbine process if the isentropic efficiency of the turbine is 85%.

2) For an ideal Joule cycle, discuss the effects of pressure ratio on the thermal efficiency using T-s diagram.