A rigid 0.1 m3 container holds 1 kg of water, initially at 25?C. Calculate the theoretical minimum work required to increase the water temperature to the point where the water exists as a single phase. The environment temperature is 25?C.
In: Mechanical Engineering
Calculate the peak cooling load from an EAST facing wall. No interior or exterior shades, no floor carpeting , medium construction
Windows: ¼ in double glass with air gap and aluminum frame
Window area = 300 ft2
Wall: 4-in Concrete + R-5 Insulation+ ½ in. gypsum wall board
Gross Wall Area = 1200 ft2
Location: Miami, Florida
Indoor Temperature = 70 oF
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4. Consider a reheat–regenerative vapor power cycle with two feedwater heaters, a closed feedwater heater and an open feedwater heater. Steam enters the first turbine at 12.0 MPa, 520C and expands to 0.6 MPa. The steam is reheated to 440C before entering the second turbine, where it expands to the condenser pressure of 0.006 MPa. Steam is extracted from the first turbine at 2 MPa and fed to the closed feedwater heater. Feedwater leaves the closed heater at 200C and 8.0 MPa, and condensate exits as saturated liquid at 2 MPa. The condensate is trapped into the open feedwater heater. Steam extracted from the second turbine at 0.4 MPa is also fed into the open feedwater heater, which operates at 0.3 MPa. The stream exiting the open feedwater heater is saturated liquid at 0.3 MPa. The net power output of the cycle is 100 MW. There is no stray heat transfer from any component to its surroundings. If the working fluid experiences no irreversibilities as it passes through the turbines, pumps, steam generator, reheater, and condenser, determine (a) the thermal efficiency, (b) the mass flow rate of the steam entering the first turbine, in kg/h. (Turbine and pump isentropic efficiencies 100% & Create a table of all values)
In: Mechanical Engineering
list electronic manufacturing processes with its applications.
In: Mechanical Engineering
A 2-in diameter jet of water having a velocity of 30 ft/s is deflected parallel to a curved vane. The jet flows freely in the atmosphere in a horizontal plane. Calculate the x and y forces exerted on the water by the vane. Defelction is 90 Degrees
In: Mechanical Engineering
A gaseous mixture of 25% CO, 25% CO2, 25% H2 and 25% H20 is brought to a temperature T and 1atm. Equilbirium composition of the gas mixture is determined by the following reaction
CO2 + H2 = CO + H20. Calulate the equilbirium composition of the gaseous phase at 700K and at 1500K. Given G at 700K is 14kJ and at 1500K is -9.6kJ
In: Mechanical Engineering
A 100-lb driver and a 2000-lb tractor lift 900 lb of gravel. Create a MATLAB program that will:
Determine the reaction at each of the two rear wheels and two front wheels.
The shift has changed and a new driver dumped some of the gravel. Ask the user the weight of the new driver and the weight of the gravel left in the tractor.
Calculate the new reaction at each of the two rear wheels and two front wheels.
Provide the user with output that describes the difference between a and c.
In: Mechanical Engineering
Consider a Carnot heat engine cycyle executed in a closed system (piston-cylinder device) using 0.01848695 kg of stem as the working fluid. It is known that the maximum absolute temperature in the cycle is three times the minimum absolute temperature, and the net-work output of the cycle is 90 KJ assuming no kinetic and potential energy changes. If the steam changes from saturated vapor (state 3=h_g) to saturated liquid(state 4=h_f) during heat rejection (process3-4) determine
a) the thermal efficiency of this Carnot Cycle
b) the head addition during the process 1-2 (isothermal expansion)
c) the heat rejection during process 3-4 (isothermal compression)
d) the temperature of the steam during the heat rejection process.
(a hint: use energy balance equation, H=U+PV, and h_g -h_f = h_fg
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Briefly describe, probably with the aid of an illustration, the injection molding process. For full credit, state what general category of polymer it is used for.
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How to calculate overall fuel economy of hydraulic hybrid vehicle? Know that fuel economy formula is litre per used over distance travelled. How to calculate the fuel used for both ICE and hydraulic system
In: Mechanical Engineering
Specify suitable machine screws to be installed in a pattern of four, equally spaced around a flange, if the clamping force between the flange and the mating structure is to be 26.7kN. Recommend a suitable tightening torque for each screw if each of them is to be stressed to 75% of its proof strength
In: Mechanical Engineering
For a base motion system described by:
mx''+ cx'+ kx = cY?b cos ?bt + kY sin ?bt
with m = 100 kg, c = 50 N/m, Y = 0.03 m, and ?b = 3 rad/s, find largest value of the
stiffness k and that makes the transmissibility ratio less than 0.75.
In: Mechanical Engineering
Naphthalene is commonly used as a repellent against
moths to protect clothing during storage. Consider a 1 cm diameter
spherical naphthalene ball hanging in a closet at 25 oC. The
density and vapour pressure of naphthalene at 25 oC are 1100 kg/m3
and 11 Pa, respectively and mass diffusivity of naphthalene in air
at 25 oC is 0.61 x 10-5 m2/s.
a. consider the variation of diameter with time,
determine how long it will take for the naphthalene to sublimate
completely.
b. If instead of being stored in a closet, the
naphthalene is exposed to dry air flowing at a velocity of 2 m/s.
Both the naphthalene and the air were kept at 25 oC. It is observed
that 12 g of naphthalene has sublimated in 15 min. Determine the
mass transfer coefficient and the flux for mass transfer from
naphthalene.
In: Mechanical Engineering
Explain with your own words, how turbulence increases heat transfer.
In: Mechanical Engineering
If a candle is lit in a spacecraft without gravity...
Question 8 options, pick one:
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a. The candle will light, but not burn very well, as no natural convection flows develop. |
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b. The candle will not light. |
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c. The candle will light and burn better than on Earth, as the natural convection flows are not held down by gravity. |
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d. The candle will light and burn just like on Earth, as natural convection flows are independent of the gravity. |
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