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  1. J

    Need to chose a sensor for a presentation

    As stated I need to chose a somewhat simple sensor (needs to be fully explained in 3 slides) for a short presentation. I cannot use anything we have discussed at length (accelerometer, strain gauge, thermocouple, LVDT). Any ideas? Thanks
  2. J

    Fluid Mechanics

    http://img90.imageshack.us/img90/9176/img062iz2.jpg [Broken] I am having trouble starting excersize 3. If both jets have the same velocity,area, and the same density what would cause the cart to move? If they are mean that the cart is given an intial velocity and I need to give an expression...
  3. J

    Engineering Filter circuits

    I did a lab using an active low pass filter with an op amp and at the end we were instructed to remove the capacitor that was in parallel with the resistor. The result was an extremely high voltage compared to the voltage with the capacitor in the circuit. We are asked to explain what kind of...
  4. J

    Laplace Transform

    Homework Statement Determine L{t sinwt} with the aid of therom 1.31 (its the General Differentiation method on this page: [PLAIN]"link"[/URL] Homework Equations Shown on linked page The Attempt at a Solution I do not understand how to start this becasue I do not have a...
  5. J

    Polar Coordinates

    Homework Statement The velocity field for a line source in polar coordinates (r,theta) is given by: V=m/(2(pi)r) (in the "e" little r vector direction) convert to cartesian and calculate the strain rate tensor. Homework Equations R=Sqrt(x2+y2); Theta=ArcTan(Y/X); Cartesian...
  6. J

    Equation for measuring strain

    I have a lab where we used the following equation to theroretically measure the strain on a cantilever beam heald stationary at the left end. Measuring back from the right side its length is L2 and the length from the free (right) end to the point where the strain gagues were was L1 (fixed...
  7. J

    Solar Future?

    I am a 3rd year mechanical engineering major currently working in an internship for a power company. My company recently sold off their wind and hydro generating plants because they could not compete with the coal plants. We now have only coal and gas/oil plants. I know that I could continue...
  8. J

    Average GPA at your school

    Again. there are a number of shortcummings of a poll of this nature but just for fun, what you you estimate is the average GPA at your particular school? I think it would be interesting to compare these numbers to the other poll about personal GPA's. (i.e. school of enginering or school of...
  9. J

    Programs Whats your major GPA .Be honest

    Whats your major GPA.....Be honest!!!!!!!!!! Just to kinda get an idea how the average user is doing. I know that there are a LOT of variables like major,school,level but just for fun lets see. And please be honest, what point would there be to "inflate your grade"? No one will know what you...
  10. J

    Heat Transfer from metal wall

    A light breeze of 10mi/hr blows across a metal building. The buildings wall is 3.7m tall and 6.1m wide. A net energy flux of 347w/m^2 from the sun is absorbed by the wall and then disipated to the air through convection. Assuming the air is 27c and 1 atm and blows across the wall as a flat...
  11. J

    Heat Transfer and resistance

    A 20-20-5 cm slab of copper at a uniform temp of 200c suddenly has its surface temp lowered to 35c. Using the concepts of thermal resistance and capacitance and the lumped-capacity analysis, find the time at which the center temp becomes 90c. density =8900 kg/m^3 specific heat = .38 kJ/kg-k...
  12. J

    Heat Transfer in rod.

    My book is fairly explicit when it comes to solving problems with rods of uniform temp, and fins that have a heat source at one end but I have a couple of HW problems that deal with rods. 1) A rod connected to 1 hot wall given: Wall temp environment temp dia. and length of rod heat...
  13. J

    Multiple device problem

    A process requires a steady supply of saturated vapor steam at 200kPa and 0.5kg/s. Also required is a steady supply of compresed air at 500kPa and 0.1kg/s. Both are to be supplied to supplied by the process shown. Steam is expanded in the turbine to supply the power needed to drive the air...
  14. J

    Mass flow rate

    Steam enters a turbine at 3 mpa and 450 c, expands in a reversible adaibatic process, (KE and PE are negligible) and exhausts at 10 kpa. The power output of the turbine is 800 kW. What is the mass flow rate? I did the problem but I don't know if the anwser is correct and wanted to check...
  15. J

    Internal energy vs. Enthalpy vs. Entropy

    Ok, I must admit that I am becoming a bit confused about these concepts. I understand that enthalpy is u + Pv, and entropy has something to do with molecular randomness. I was fine until we started to solve for heat transfer when dealing with entropy and now I am confused, sometimes we use...
  16. J

    Heat transfer from inside to outside

    An insulation system is to be selected for a furnace wall at 1000 deg C using first a layer of mineral wool blocks (k=.091 W/m-c) followed by fiberglass boards (k=.0425 W/m-c). The outside of the insulation is exposed to an environment with h= 15 W/m^2-c and temp of 40 deg C. Claculate the...
  17. J

    Reversible Process?

    A cyclic machine receives 325 kJ from a 1000 K energy reservoir. It rejects 125 kJ to a 400 K energy reservoir, the cycle produces 200 kJ of work as output. Is this cycle reversible, irrerversible, or impossible? Not exactly sure what he is looking for here. But, since W=QH-QL, does that mean...
  18. J

    Heat Transfer - Conduction

    A truncated cone 30cm high is made of Aluminum. The dia at the top is 7.5cm, and 12.5cm at the bottom. The lower surface is maintained at 93 deg C, the upper surface at 540 deg C. the other surface is insulated. Assuming 1 dimentional heat flow, calculate the rate of heat transfer in watts...
  19. J

    Electric Circuits Book

    I am taking an electric circuits course using Intro to Electric Circuits 7th ed. by Dorf/Svoboda. My professor mentioned something about a manual that you can buy that has mainly just a lot of different circuits all worked out for you to study, does anyone know where I can get this because the...
  20. J

    Career Direction

    Career advice desperately needed I am a currently a junior in college working in a co-op rotation for a major power company. I work in predictive maintenance doing a lot of infrared scans, vibration testing, motor circuit tests, trend building and evaluation, fan and pump balancing, etc… I...
  21. J

    Steam Turbine generator work done

    I will start my junior year as a ME major in the fall, I currently am working for a power company on a co-op. I work with the Predictive Maintance department corporate so I am not at the plant all the time but have a question about the turbine that might be more of a generator question. If...
  22. J

    Average scores

    Just curious as to what the grading is like around the country, which best describes the average test score in your engineering classes (without a curve)?
  23. J

    Long range effect of Nuclear Power plants.

    I have recently become interested with the return of Nuclear Engineering with the recent political climate change over our dependence on foreign energy resorces. I know that there is another thread which discusses the prospects of new plants in detail, however I wanted to look at the long range...
  24. J

    Steam turbine

    A steam turbine has an inlet of 2kg/s water at 1000kPa and 350C and velocity of 15m/s. The exit is at 100kPa, 100% quality and very low velocity. Find specific work and power produced. I have done a lot of these problems but it usually says adiabatic or the inlet and exit temp is the same...
  25. J

    Specific enthalpy of air

    I'm sure this is a really dumb question, but how do you find the specific enthalopy of air at a given temp and pressure? I Have been using my thermo tables for everything but I do not have tables for air. The only tables for air that I see list the properties at .1 Mpa and I need it at 200, and...
  26. J

    Liquid water turbine

    A liquid water turbine recieves 2kg/s water at 2000kPa, 20C, and velocity of 15m/s. The exit is at 100kPa, 20C and very low velocity. Find specific work and power produced. From my tables I get hi=85.82 kJ/kg he=84.03 kJ/kg Energy equation reduces to: \begin{array}{l} h_i +...
  27. J

    Pump and nozzle

    Consider a water pump that recieves liquid water at 15C and 100kPa, and delevers it to a same diameter short pipe having a nozzle with exit diameter of .01m to the atmosphere at 100 kPa. Neglect KE in pipes and assume constant internal energy u for water. Find exit velocity and mass flow rate if...
  28. J

    Can't seen to get the right solution-A sluice gate dams water up

    Can't seen to get the right solution- A sluice gate dams water up 5m. A 1-cm dia hole inthe bottom of the gate allows liquid water at 20C to come out. Neglest any changen in internal energy. Find exit velocity and mass flow rate. governing eqn- hi=he+1/2v^2 I found...
  29. J

    Nuclear Engineering

    I am a Mechanical Engineering major and my school has recently revived its Nuclear Engineering classes. They are comming out with a 3 course sequence followed by 2 electives for a certificate of Nuclear Engineering to be added to my degree. To do this I would have to use my 3 technical electives...
  30. J

    Ballistics test

    I have been given kind of a bonus question that requires a little thinking and I wanted to ask if I am going in the right direction with my thinking as I am new to Materials Science. Given: Ballistics test in which a high velocity projectile is fired at a block of material. Isotropic. Does...
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