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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. The soap bubble isn't exact, but it is approximately the optimal shape plus it's easy to visualize and it also works for shapes that aren't round. Ideally, the surface energy is minimized, which is proportional to the area and also the stresses. Consider this… >---< [abrupt necking at both ends with very narrow tube in between] would have less surface area than )===( [slight neck down on both ends with a tube in the middle having a minimum diameter close to that of the smaller end]. While the first example would have less surface area than the second, the stresses would be much larger be
  2. I won't solve your structural problem for you, but I will share a story. The hyperbolic shape of natural draft cooling towers is entirely structural. The shape is not to induce or optimize the flow of air through the tower. The shape is to achieve the least materials and expense. The thickness of the concrete in the shell is the minimum required to cover and protect the rebar. This is not true at the bottom or veil where the shell sits on columns, which is much thicker. The shape is obtained by stretching a soap bubble between two circles of wire. The soap bubble naturally achieves the surface
  3. DrD posted 1 hour ago! Are you still there? I've been so worried that COVID got you. TMR has disappeared and your phone at the rectory has been disconnected.
  4. I am an engineer and applied mathematician who just happens to write software. I've written a lot of it since 1974—about three million lines of assembler, FORTRAN, and C. I have always written software to get some particular job done. If the subject matter didn't fall into one of my areas of expertise, I worked with someone who knew the important details. Examples of this cooperation include: geohydrologists, meteorologists, and biologists. I can't imagine writing software with no particular foundation. I have never sat through a single class in computer programming. Instead, I made a wager: I
  5. Sorry to have taken so long to respond… The main difference between spark-ignition (gasoline engine) and compression-ignition (diesel engine) operation is constant volume vs. constant pressure combustion. In a gasoline engine, combustion occurs so rapidly (the fuel and air are already in the combustion chamber with the plug fires) and near the top of the stroke so that the crank has little time to rotate and the piston moves only slightly with little change in volume. In a diesel engine, the fuel is sprayed into the cylinder as the piston is falling so that combustion occurs over a longer inte
  6. Sorry to rant, but… Just to give you a little appreciation for size… It takes the total output of Norris Dam just to run the fans on the cooling towers at Browns Ferry Nuclear Plant. Think fan on the radiator of your car compared to the engine. I have published multiple papers on BFNP and the cooling towers. Chuck Bowman designed those too (steam system thermal and cooling towers) plus Cumberland Steam Plant, Paradise Steam Plant Unit 3, Watts Bar Nuclear, Sequoyah Nuclear, Bellefonte Nuclear, Phipps Bend Nuclear, Hartsville Nuclear, and Yellow Creek Nuclear. CRC Press just released Thermal En
  7. Sorry for the long reply but the question is important and also complicated. Wind power is like a sneeze compared to a hurricane (supply to consumption). So is tidal power. I've been inside the power station at the Bay of Fundy, which has the largest tidal fluctuation in the world. Besides the fact that changing the resonance of the harbor (like stuffing a guitar with cotton) would diminish the tides, the thing is like a little lego toy compared to a real dam. I've crawled inside the turbines and generators of *real* dams, including: Norris, Fontana, and Chickamauga. The coal plant a mile from
  8. Did you measure the discharge pressure and/or head and how did you accomplish this? The discharge pressure (and head) will depend on several things, including where the fluid is coming from and going to.
  9. I can probably help you with data but I need more information about what you hope to accomplish. What type of reactor?
  10. Adjectives "high" and "low" are always relative terms. High or low may be compared to atmospheric on Earth or the critical pressure of the fluid in question. These terms might even be related to the capability of commonly available pumps. In this current discussion both water and CO2 have been mentioned, so "high" pressure would be in relation to the critical pressure of H2O (22 MPa) and that of CO2 (7 MPa).
  11. Recent power outages in California before the current fires reveal the weakness of "green" power solutions. While these sound good, in practice they are not resilient and have little reserve, thus falter when stretched. This trend will only worsen. Managing diverse power resources is a rapidly growing field creating jobs. You might want to explore this topic.
  12. Please repost with description. The pdf says "unavailable".
  13. I have seen this same thing many times. The overall surfaces are experiencing typical corrosion, which can be surprisingly difficult to prevent. The more extreme spots (especially the ones circled) were initiated by handling (bumped, scraped, dinged). The less extreme spots arise from debris that is no longer present, but facilitated and concentrated the chemical attach at those locations. These surfaces are not in the least unusual. Preventing this from happening requires considerable diligence and at least one of several available coatings. Note that if you coat a surface and it has any flaw
  14. If you're going to eventually make a living, ditch the Mac and get a Windows laptop. I am no fan of Bill Gates or Windows, but I accept the facts of life as they are. Unless you're going to work for the government or stay in academia, LINUX is also out. The vast majority of engineering software runs on Windows and most businesses circulate documents and spreadsheets created with MSO. There is no need to buy a new machine. Good reconditioned laptops are readily available on the Web for $200. After decades of industrial use, I can also say that Dell laptops significantly outlast all others. [No,
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