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Mechanical Engineering


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dudleybenton last won the day on February 26

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About dudleybenton

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    Knoxville, TN, USA

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  1. A utility burning landfill gas didn't realize their NOx reduction feed led to production of cyanide! Chemical reactions can be quite complex, which is why you need special software that can handle nonlinear and non-ideal problems swiftly and accurately. This figure shows the impact of air:fuel ratio on the production of cyanide, carbon monoxide, and hydrogen sulfide, three toxic gases they didn't realize they were spewing into the environment at this supposedly "green" facility. Search Amazon books for "Thermochemical Reactions" and click on "Look Inside" to read about the solution hidden for
  2. This is vague so that I'm not even sure what your question is. Are you suggesting that someone might be able to deduce the type of turbine given two temperatures? I very much doubt that. I have worked with gas turbines for years, yet your terminology is unfamiliar. I suggest you search the web for an actual turbine from one of the big manufacturers (GE, Siemens, Mitsubishi, Solar) and review the section details.
  3. Then no one should mind if you spray a little water around to keep the electronics cool. Evaporative cooling is probably the simplest, cheapest, most reliable, lightest, least complicated method to use. Compressors, refrigerants, thermo-electric, semi-conductor, and other high-tech options sound good but are usually a nightmare to implement and keep working.
  4. There are several options. What is practical depends on the application. Is this robot supposed to enter a burning building or a failed nuclear system or a wood drying kiln or what? I have had various electronic devices fail in conditions I had to put up with, like 50°C and 100% relative humidity atop a cooling tower. Have you ever been inside a coal plant or gas turbine combined cycle plant when it was running? I have been countless times. I once stepped out of a plant in Muskogee Oklahoma into 36°C bright sunlight and shivered at the temperature drop. My coworkers have had to endure 63°C amb
  5. This animated model is rendered using OpenGL. The source code is available free online along with other examples, including a T-Rex. [Google "3D Articulation"]
  6. The knight's tour is when the knight, alone on the chessboard, makes 64 moves, landing on each square once and only once. I have written millions of lines of code but have never sat through a single class on computer programming. I had to pass the course to graduate so I made a proposition. The instructor would assign me a problem. If I could solve it, I would get an A and he would never see me again. The year was 1974 and the problem was the knight's tour. Two days later I turned in the solution in FORTRAN on punch cards. I did not know he had been given the problem in graduate school but had
  7. I wrote this screen saver in 1992. It doesn't use one of the algorithms popular today. Instead, it's recursive like qsort, splitting the domain into smaller and smaller pieces. This process naturally results in triangles that are nearly equilateral. When using FEM, you want to avoid acute angles if possible.
  8. When I was in college 40+ years ago, simply running even an elaborate example using somebody else's software was not considered worthy of an advanced degree. We had to write the software ourselves. I am saddened by how many students run a model using Fluent or COMSOL or FOAM or Ansys or ABAQUS or write a bit of Python and consider the job done. You are short-changing yourself if you stop there. I can build a CFD model in 15 minutes. Don't take the easy path. The view at the end of the steep and rocky path is worth the climb.
  9. This isn't the most detailed or efficient model. It's brute force solution of the transient Navier-Stokes equation using finite differences. The nast2d source code can be found on the web.
  10. Resistance (air, road, rolling, drag, whatever) are all forces in the direction opposite of forward motion (i.e., -F). What you're integrating is Newton's 2nd Law or ΣF=d(mV)/dt where F and V are both vectors. In this case there's only one direction so the vector notation isn't necessary and dm/dt is negligible. RK4 (or Euler's method in an Excel spreadsheet) integrates A=ΣF/m=dV/dt and then V=dX/dt. The engine is providing +Power/V less the Drag so that dV/dt=P/V-D. P is a function of rpm, which is a function of V and gear ratio. D is a function of V.
  11. I suggest you get a co-op job for 3-6 months. You may soon find out what you love and hate. Give me a spot under the stairs like Harry Potter so I can work and avoid managers. You may like management. Everyone is different. We need good leaders, nerds, and hands-on workers to get the job done. In my experience, there are exceedingly few people who can actually run a company effectively. I am not one of them.
  12. I have seen this before on a variety of thread sizes, so this is not a unique problem. I run a die on the one and a tap on the other. You may need to turn the die upside down to finalize the thread, because it will be tapered on the starting side. If the two still don't fit right, it's a tolerance issue in the manufacture of the tools. The next thing to try is getting the tap and die from the same manufacturer. If it still doesn't work, you must file the threads. There are special little files in several shapes for this purpose. They're expensive, but worth the investment.
  13. see attached explanation and spreadsheet... expansion.pdf expansion.xls
  14. Isn't this exactly what a RedBox does with DVDs? Unless you want to make a lot of these dispensers and have a lot of money to spend (hopefully to recover later), you will need to find a mechanism that already exists and is already mass produced so that you can adapt it cheaply. When I needed such a thing, I went looking at what people had until I found something I could use. Vending machines would be a place to start.
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