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Mechanical Engineering


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dudleybenton last won the day on August 9

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About dudleybenton

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    Knoxville, TN, USA

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  1. 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.
  2. Please repost with description. The pdf says "unavailable".
  3. 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
  4. 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,
  5. There are many creative designs for cooling chips, especially graphics processors, created by users with available parts. I am surprised that you have not found images of these with a Google search. Try different search patterns and don't give up.
  6. If there is any way you could co-op (work for a company who builds agricultural mechanization devices for several months each year) that would be most enlightening. I know a recent graduate of the university here who has already participated in exciting implementations and has several job offers to choose from. This is a wonderfully productive and growing profession.
  7. I recently spoke to a friend who is hiring young engineers to work at several large power plants needing modernization. He said that the new hires know how to operate battling robots using their iPhone and 3D print useless plastic objects but don't understand thermodynamics or heat transfer. Please prove him wrong by mastering the foundations of industry! This website can help make that possible.
  8. We need more details to address this question. Do you mean an air powered siphon? Do you mean air bubbles rising in a vertical pipe producing an upward movement of the surrounding water? A picture of the device would help.
  9. Two months before my third birthday I changed all the light bulbs on the Christmas tree to be red yellow green red yellow green... I dismantled the radio at age seven and the television at eight. These were the old kind with vacuum tubes and did not survive the process. I rebuilt my first engine at eleven and was working as a professional mechanic by fourteen—before I could drive a car. I have a grandson who is three and destined for the same path. My father didn't know which end of a screwdriver to hold. The engineer gene came from my maternal grandfather.
  10. Fluids above the critical temperature are called "super critical." We sometimes call a liquid above the critical pressure "super critical." For example, in most large coal-fired steam power plants, the feedwater entering the boiler is about 4400 psia (30 MPa). The critical point is where the saturated liquid and vapor are indistinguishable; that is, a distinction is physically meaningless. There are no bubbles formed when boiling a liquid above the critical pressure. This is why you must have special equipment to clean (i.e., "polish") the feedwater in a supercritical coal-fired plant, as the
  11. The seawater probably flowed on the inside of the 90/10 Cu-Ni tubes at about 7 ft/sec (2 m/s), so multiply nD²π/4 to get volumetric flow then by density to get mass flow. You get surface area the same way. The overall heat transfer coefficient, U, is probably about 5 BTU/hr/ft²/ºF (25 W/m²/ºC). The delta-T is probably about 15ºF to 25ºF (8ºC to 14ºC). The specific heat of natural gas is about 0.5 BTU/lbm/ºF (2 kJ/kg/ºC). From that you can calculate the flow rate of natural gas and estimate the heat transfer capacity.
  12. There are several excellent texts on this subject. I always recommend Lindon Thomas' Heat Transfer because he's been a friend for many years. This is a large topic. To get a meaningful answer, you must further qualify your question. What type of heat exchanger? What do you expect it to do? What fluids? What temperatures? What flow rates? Heat exchangers are used for everything from natural gas to peanut butter.
  13. You will find many projects on ResearchGate where graduate students are investigating heat transfer within enclosures with a variety of conditions and fluids. You should be able to find something informative to your particular problem there. The complexity of the solutions varies considerably, so look for something on the level you're interested in pursuing.
  14. While pressure is clearly absolute (i.e., zero has a clear definition), temperature is most often with respect to some state (e.g., minimal crystalline structure). We can readily measure conditions and calibrate pressure instruments on an absolute basis. We don't have the same flexibility with temperature and so we recognize this in our measurements, calculations, and formulations. Also, heat is defined as that form of transient energy that crosses a system boundary by virtue of a temperature *difference*, not an *absolute* temperature.
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