For liquids, the viscosity decreases as the temperature increases. For gases, the viscosity increases as the temperature increases. Your objective is to provide an explanation for these trends. You may do internet research, but your response must be in your own words and references provided. Your response must be typed and grammatically correct.
In: Mechanical Engineering
If the cells operate with 18% efficiency, and there is no mismatch loss among the cells, calculate the overall module efficiency if the round cells are used. Assume a PV Module is to have dimensions of 37.5 X 63.2 in. Also assume that 8-in. round cells are available
In: Mechanical Engineering
A local firm manufactures children's toys. The project demand over the next four months for one particular model of toy robot is
| Month | Workdays | Forecasted Demand |
| July | 23 | 3825 |
| August | 16 | 7245 |
| September | 20 | 2770 |
| October | 22 | 4440 |
Assume that a normal workday is 8 hours. Hiring cost are $350 per worker and firing cost (including severance) are 850 per worker. Holding cost are $4 per aggergate unit held per month. Assume that it requires an average of 1 hour and 40 minutes for one worker to assemble one toy. Shortages are not permitted. Assime that the ending inventory for June was 600 of these toys and the mangager wishes to have at least 800 units on hand at the end of October. Assume that the current workforce level is 35 workers. Find the optimal plan by formulating as a linear program.
In: Mechanical Engineering
A stainless-steel rod (AISI 304) of length ? = 100[??] and triangular cross-section is attached between two isothermal heat sinks at ?0 = 50℃. The rod perimeter is ? = 5[??]. When an unknown fluid at ?0 = 23℃ is in cross-flow over the rod, the temperature of the rod is midway between its two ends is measured to be ???? = 25℃. Determine the value of the convection heat transfer coefficient and the rate of heat loss from the rod.
In: Mechanical Engineering
1. What problems are associated with oxygen or other gases that are dissolved in molten steel?
2. What is considered a low-carbon steel? Medium-carbon? High-carbon?
can you please type the answer. thanks
In: Mechanical Engineering
Examine the following abstract:
“In this study, we investigate the behavior of new nano ZrO2 and Al2O3-13 wt.% TiO2 thermal sprayed coatings on commercially pure (cp)-Ti (grade 4) and titanium alloy substrates. Friction and wear tests against Al2O3 balls showed that the wear resistance of Al2O3-13 wt.% TiO2 is better than that ZrO2 coating. Both plasma sprayings have similar abrasive wear behavior; however, the average friction coefficient is higher for alumina-titania coating. Electrochemical tests, open circuit potential monitoring and potentiodynamic polarization, were performed in simulated body conditions (Hank's solution, 37 degrees C). Results showed that corrosion resistance was appreciably higher for alumina-titania coating.” INTERNATIONAL JOURNAL OF REFRACTORY METALS & HARD MATERIALS 28(1):115-120 Jan 2010
a) What is the purpose (purposes) of these nano ZrO2 and Al2O3-13 wt% TiO2 coatings on CP Ti and Ti alloys?
b) If these materials were used as a femoral stem, would the results of wear tests be important? What if these were coating for the femoral head?
c) What would be the ideal, long-term outcome of this coated Ti when used as a femoral stem? Please describe the key features of the implant that are critical to its success. (Be sure your answer includes responses to the following questions: What is its physical shape, does it have porosity or roughness, how do you intend the tissue around the implant to interact with the implant?)
In: Mechanical Engineering
What caused the Open Paradigm? Give examples
In: Mechanical Engineering
just need to find out how to find the new yield point of a metal after it has been stretched ?
give the formula and explain it please
In: Mechanical Engineering
List the 6 different steps in systematic design process and explain each step.
In: Mechanical Engineering
Nitrogen can be liquefied using a Joule-Thomson expansioni process. This is done by rapidlyl and adiabatically expandign cold nitrogen gas from high pressure to a low pressure. If nitrogen at 135 K and 20 MPa undergoes a Joule-Thomson expansion to 0.4 MPa,
a. Estimate the fraction of vapor and liquid present after the expansion, and the emperature of this mixture using the pressure-enthalpy diagram for nitrogen.
b. Repeat the calculation assuming nitrogen to be an ideal gas with Cp* = 29.3 J/molK
In: Mechanical Engineering
A smooth rectangular duct 300 mm by 400 mm carries air at a rate of 1 m3/s.
Take the density of air to be 1.204 kg/m3 and the dynamic viscosity of air to be 1.825x10-5 kg/ms.
Calculate the friction factor for the duct.
In: Mechanical Engineering
Design a Matlab program for the Brayton Cycle. The program would be for a standard air cycle. The program should show specific work and thermodynamic efficiency from r=1 to 50, t=1 to 5 , where r is the pressure ratio and t is the temperature ratio,
In: Mechanical Engineering
To obtain monochromatic x-rays from copper one must avoid or eliminate the Kβ to obtain only Kα. One possible method is to use an electron energy above the Kα critical value of ~8.0 keV, but below the Kβ critical value of ~8.9 keV. Instead a potential energy of 40-50 keV is typically used, with a filter to remove the Kβ. Explain why this might be better than the first method.
In: Mechanical Engineering
Uniform internal heat generation at q˙ = 2.00 × 107 W/m3 is occurring in a cylindrical nuclear reactor fuel rod of 50-mm diameter, and under steady-state conditions the temperature distribution is of the form T(r)=a+br^2, where T is in degrees Celsius and r is in meters, while a= 800 °C and b= -4.167 × 105 °C/m2. The fuel rod properties are k= 30 W/m·K, ρ= 1100 kg/m3, and cp= 800 J/kg·K.
Please write legible.
Find the steady state temperature gradient, dT/dr, at the outer surface of the rod, in °C/m.
What is the steady state rate of heat transfer at the outer surface, in W/m?
Immediately after the sudden increase in reactor power level (at t= 0 sec), what is the temperature at the centerline?
Immediately after the sudden increase in reactor power level (at t= 0 sec), what is the time rate of temperature change, dT/dt, at the centerline, in °C/s?
In: Mechanical Engineering
Which of the following is NOT one of the four criteria by which the size of a hydraulic reservoir is determined?
It must make allowance for dirt and chips to settle and air to escape
Its inner surface must be covered with a layer of stainless still to avoid corrosion
It must maintain oil level high enough to prevent a whirlpool effect at the pump inlet
It must have a surface area large enough to dissipate heat
All of the above
Which of the following is the main advantage of the piston type accumulator over other gas type accumulators?
Its ability to handle very high or low temperature system fluids
Its small weight-to-volume ratio
A positive sealing between the gas and oil chambers
Its exclusive use of nitrogen
None of the above
In: Mechanical Engineering