. You have two thermal couples. One thermal couple is fixed in space at (Xo,Yo,Zo) and the second thermal couple is moving in space. At time to, the second thermal couple moves to location (Xo,Yo,Zo). Assuming the temperature is not uniform in space.

Are the temperatures measured from the two thermal couples the same ?

Are the rate of changes of temperature the same?

Please be clear I really want to understand the concept, Thank you for your help (:

2. If produced by Method A, a product’s initial capital cost will be $100,000, its operating cost will be $20,000 per year, and its salvage value after 3 years will be $20,000. With Method B there is a first cost of $150,000, an operating cost of $10,000 per year, and a $50,0000 salvage value after its 3-year life. Based on a present worth analysis at a 15% interest rate, which method should be used?

2. If produced by Method A, a product’s initial capital cost will be $100,000, its operating cost will be $20,000 per year, and its salvage value after 3 years will be $20,000. With Method B there is a first cost of $150,000, an operating cost of $10,000 per year, and a $50,0000 salvage value after its 3-year life. Based on a present worth analysis at a 15% interest rate, which method should be used?

Estimate the heat loss rate from a person who can be approximated as a cylinder of diameter 0.3 m and height 1.8 m. The (clothing) surface temperature is 23 °C and the cross wind flow velocity is 15 m/s. The ambient temperature is –23 °C. Neglect end effects from the cylinder. Assume steady state.

Two sections of a pressure vessel are to be held together by 5/8 in-11 UNC grade 5 bolts. You are told that the length of the bolts is 1.5 in, the length of the threaded portion of the bolts is 0.75 in, and that their elastic modulus is E=30 Mpsi. The total load on the joint is 36 kip and the stiffness of the members is given as km=8.95 Mlbf/in. What is the minimum number of bolts that should be used to guard against excess proof strength with a factor of safety of np=1.2? Be sure to make an estimate for the preload.

A deli meats factory pumps a liquefied meat mixture through round plastic pipe that is 75mm inside diameter. Assume that the liquid meat mixture has a specific gravity of 0.9, a dynamic viscosity of 0.1N∙s/m^2, and that it flows at an average speed of 0.5m/s.

a) What is the kinematic viscosity of the liquefied meat mixture in m²/s?

b) What is Reynolds number for liquefied meat mixture?

c) Is the flow laminar or turbulent?

d) What is the mass flow rate in kg/s?

You have to build a long cylinder that will be compressed at an angle slightly askew from the long axis of the cylinder. That squeezing force will cause a Z-axis pancake stack (like most of our printed cylinders are) to shear apart at printed layers.
What modifications do you suggest to the print of this cylinder that can resist this compression force?​

In 50-100 words describe how culture and training allowed the Uberlingen disaster to happen

Bananas are to be cooled from 28°C to 12°C at a rate of 1140 kg/h by a refrigerator that operates on a vapor-compression refrigeration cycle. The power input to the refrigerator is 9.8 kW. Determine (a) the rate of heat absorbed from the bananas, in kJ/h, and the COP, (b) the minimum power input to the refrigerator, and (c) the second-law efficiency and the exergy destruction for the cycle. The specific heat of bananas above freezing is 3.35 kJ/kg·°C.

Consider a large tank holding 50 gal of pure water into which a brine solution of salt begins to flow at a constant rate of 6 gal/min. the brine leaves the tank at a rate of 5 gal/min. If the concentration of salt in the brine entering the tank is 0.1 lbs per gallon, determine the function X that will determine the amount of brine in the tank at any time t.

In 50-100 words describe ADS-B. Explain how this technology will allow for reduced separation during cruise flight (from 3 miles down to as little as 1 mile).

(type if possible) As you’ve seen, static pressures increase with decreasing velocity. Qualitatively describe how this principle explains how an airplane wing generates lift. How might such an analysis be useful in designing certain types of hydraulic structures where the long-term effects of static pressure differences may cause damage and/or failure of the structure? Such problems can be minimized by proper consideration of the flow properties or by overly strengthening the structures. Which approach is most desirable from the standpoint of safety? From the standpoint of cost? From the standpoint of long-term durability and maintenance concerns? Why? 3. Given your experience with flow acceleration

A 2 in schedule 40 pipe insulated with 1 in of 85% magnesia is carrying a fluid at 800°F. The insulated pipe passes through a room at 80°F, and the outside surface of the magnesia is at 100°F. Please calculate

The total heat loss per linear foot of pipe (in Btu/h),

The temperature of the inside wall of the pipe (in *F), and

The heat transfer coefficient between the fluid inside the pipe and the inside pipe wall (in Btu/h?ft²?F°).

The outside heat transfer coefficient is 10 Btu/h?ft²?F°.

What toughening mechanisms are present in the cermets (10% Vol 316L-90%TiC & 20% Vol 316 L 80% TiC) that are not in not present in alumina? Discuss these

mechanisms and the difference in fracture toughness between the alumina and the cermet .

A micro gas turbine is designed to operate on the regenerative Brayton cycle and is sized to produce 400kW of net electric power. Air enters the compressor at

100kPa and 300K (dead state), and is compressed in a centrifugal compressor with a

polytropic efficiency of 86%. The air leaving the compressor enters a recuperator with

an 90% effectiveness and is heated before it enters the combustor after suffering a

pressure loss of 2.5% of the compressor exit pressure in the high-pressure side of the

recuperator. The combustor is designed to burn methane (CH4) with excess air beyond

the stoichiometric ratio to maintain a 1250K turbine inlet temperature, based on the release of the reference enthalpy of combustion, ?HR, LV for CH4. The pressure drop in the combustor is 1.5%. The turbine expands the combustion products with a polytropic efficiency of 87%. The gas flowing through the turbine can be treated as air, albeit with a slightly higher mass flow to account for the fuel burned in the combustor and with a temperature-dependent cp. The exhaust gas (also assumed to be air with temperature-dependent cp) passes through the hot-side (lowpressure side) of the recuperator and experiences a 3.5% pressure drop as it transfers heat to the high-pressure air exiting the compressor. The exhaust gas is then discharged into the atmosphere (100kPa), experiencing a further 2.0% pressure drop in the exhaust system. The air should be treated as a gas mixture with temperaturedependent specific heat (use “AIR_ha” in ees). The electromechanical efficiency of the turbine and its electric generator is 92%. Fuel pump power can be ignored. Use EES software to solve the problems.

a. Sketch the flow diagram of this system showing the key state points and show

these points on a T-s diagram.

b. Calculate the stoichiometric fuel/air mass ratio for methane (CH4). Include the

equation in your ees program.

c. Varying the compressor pressure ratio from 2.5 to 12.5 in small increments of

0.5, conduct a parametric study to determine the optimum compressor pressure

ratio, and plot the variation of the thermal efficiency with the compressor

pressure ratio. Use ?HR to compute the fuel/air ratio, from which you can compute the equivalence ratio, ?, relative to the stoichiometric fuel/air ratio given in the lecture slides

d. What is the pressure ratio at the peak efficiency point (within 0.5)?

e. Compute the total air flow rate (kg/s) at the peak thermal efficiency point for

400kW of net electric power.

f. What is the equivalence ratio, ?, at the peak efficiency point, and the fuel injection

rate (kg/s) required to raise the temperature from the recuperator air exit

temperature, Tr, to the turbine inlet temperature, T3 = 1250K.

g. How much CO2 does this system produce at its peak efficiency point in kg/kW

of net output.

h. Assuming that the exergy of combustion is equal to –?G of the methane reaction

with air, calculate the exergy efficiency of this system as a function of 4 pressure ratio and plot the results, assuming that the heat losses from the system boundary are negligible and that 45% of the exhaust exergy will be beneficially utilized in a waste heat recovery system and the rest is wasted. Assume a dead state temperature, To = 300K and dead state pressure, Po = 100kPa (Obtain “–?G” for CH4 )

i. What is the pressure ratio corresponding to the peak exergy efficiency (within

0.5)?

j. Note 1: The isentropic efficiencies of the compressor and the turbine can be

calculated from the corresponding polytropic efficiencies and pressure ratios

using the formulas given in the lecture with k = 1.4.

k. Note 2: The specific heat of air in all the calculations should be assumed to be

temperature-dependent. Use Air_ha in EES to compute the enthalpy

and entropy of air in EES “Thermophysical properties/Real fluids”.