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Everything posted by Exploro

  1. I don't have my work in a format that I can simply drop into the post editor. However what I can say is that it was the way in which I was finding the constants of integration that seemed to have been the problem. Using the deflection equation and applying the boundary conditions at the supports, letting those be distances a and b from the origin point, is 0 m each, and switching on the appropriate singularity functions and manipulating the equation to get the sum of these functions onto the right hand side, I wind up with a system of two equations: C1(a) + C2 = Sum of Singularity Functions 1 C1(b) + C2 = Sum of Singularity Functions 2 At first, what I did was put this system into matrix form and then row reduce to obtain C1 and C2. Even though the row reduction was done properly (I'd feed Wolfram the matrix and it spit out constants identical to my hand written solution). However, something was not working as I was failing to get constants that would result in the deflection of the free ends being identical in value. Meaning the resulting deflection equation could not be trusted to compute deflection anywhere along the beam. I happened to be watching this MindYourDecisions video a couple of days ago that showed a method of solving as system equation I did not consider, solving the system by subtracting one equation by another to eliminate terms. I tried the method out, Subtracting the second equation by the first to eliminate the C2 term, then solve for C1. Once C1 was obtained, I plug that value into the first equation to get C2. It worked. For both a test case and for the project problem, I got identical values for deflection at the overhangs.
  2. My brain momentarily though the number achieved was 100 factorial. Anyway, 698
  3. In a recent project, my mechanics of materials class was given a simply supported beam with double overhanging free ends. The beam is symmetrically loaded with two identical concentrated loaded at the ends of the beam and a rectangular distributed load acting between the supports. Choosing to avoid the headache of superposition, I wrote a loading equation using singularity functions, iteratively integrating until I had the slope and deflection equations and then solved for the constants of integration. Nothing seemed to indicate anything would go wrong, and yet, when trying to show that the free ends would have the same deflection, I can't seem to get deflections that are identical. I know it is not due to the constants of integration. I repeated the calculations exhaustively, even plugging the system of equations into Wolfram Alpha's reduced echelon form calculator confirms the constants are what they should be. I'm at a loss as to what else could be wrong. Are symmetrically loaded beam with double overhangs a case where equations written with singularity functions break?
  4. Granted. Maria Sirona soon exhibits a wit from which there is no escape and many a wish becomes corrupted beyond recognition. And thus Maria Sirona forever becomes known as the destroyer of dreams. I wish for snow.
  5. Granted. You are instantly transported to the Moon and you experience lunar surface gravity. However, the problem is the wish granter neglected to provide you with an EVA suit. So you only enjoy the experience for a few seconds before succumbing to exposure to vacuum. I wish that Leitbur would make more albums.
  6. Isn't that two wishes? But no matter, Granted on both counts You get your copy of UOS and you've successfully installed it. But sometime later, thanks to Termlink, someone hacks into your system and ganks your files. As for the 50-Shades-of-Green display, you get that too, but it is a retail display stack of books penned by E.L. James with that as the title. Oh...my wish. I wish to find my missing bottle of Sriracha Sauce.
  7. Granted. But you soon find the true meaning is all the more horrifying than you realize. I wish my ginger tea actually had ginger flavor.
  8. Shpaget is correct. According to a Wonderhowto article on making home-made solid fuel, melting the sugar improves the absorption of the Potassium Nitrate into the fuel mix.
  9. In the case of the speed of light, the value is based not on arbitrary choice but rather the value arrived at by several measurement experiments conducted over the span of a century. (Textbooks generally round up to the 300,000 km/s we often cite). I imagine the same is true for the speed of sound; a value arrived to by a compendium of measurements.
  10. Granted. But the price is to surrender your physical three dimensionality...you are now as flat as a piece of copy paper. As I am not feeling particularly imaginative, my wish is for a surprise. This should be interesting.
  11. Granted. However the fish you receive is the dreaded Candiru! My wish is a dish made of fish; sushi that is so delish!
  12. I concur. A quick excel spreadsheet done up after reading your post got positive values at AR of 9.75 and greater sticking with the value of G and L/D of 20. A positive value in the radican is positively good news. This is splendid. Thank you Mikegarrison.
  13. Greetings Mike. Thank you for fielding my question. The reason for estimating the wing loading is to come up with preliminary sizing of the wings. In the edition of the book I am using, the wing's reference area is calculated with wing loading as a variable. Identifying the reference area and knowing aspect ratio will give an estimate on wing span. The value of aspect ratio I used was actually referenced from Table 4.1, where the equivalent aspect ratio for sailplanes was listed as 4.464 at best L/D. However, I defer to your feedback and will try a different aspect ratio.
  14. As a starting point for an R/C glider project, I am attempting to estimate the wing loading (W/S) using an equation given in Dan Raymer's Aircraft Design: A Conceptual Approach, where wing loading is expressed a follows: W/S = [-(-G) +/- {(-G)2 - (4 CDO / pi A e)}](1/2)*[(q pi A e)/2] (An equation generator would be a nice addition to the editor) Where G is the ratio of the vertical speed and forward speed of the glider, CDO is the zero-lift drag coefficient, q is the dynamic pressure, A is the aspect ratio, and e is the Oswald Factor. Assuming a glide ratio or 20 to 1, and an airspeed of 10 m/s, the rate of decent will be approximately 0.5 m/s, thus G will be -0.04995. CDO and e are assumed to be 0.015 and 0.8 respectively. Earlier on in the text, Raymer identifies an aspect ratio for sailplanes/ gliders to be about 4.464. And lastly, q was determined to be 60 N/m2. Now. The trouble I am having is that when evaluated, the difference within the radicand is a negative value. Meaning, one can not obtain a real solution with this equation. A complex one is obtainable, but is that appropriate? Is there a different method for estimating wing loading other than that presented by Raymer.
  15. The use of winglets has a lot to do with the reduction of induced drag caused by wing tip vortices, improving efficiency and performance overall. Dryden states winglets allow for 7% increase in mileage.
  16. Three years ago while cycling, I came across a cooler filled with Rhubarb stalks. Taped to it was a sign that read "Free!". I don't know what compelled me to partake of what was offered, but nonetheless I did. But what does one do with stalks of Rhubarb? The answer; Cobbler. However, it should be made known that I had never made a Cobbler by that point in time before. Cooking the Rhubarb; sliced into manageable chunks, was easy. The stalk chunks, sugar, and water was cooked in a sauce pan to prepare the filling. The jam-like substance left in the pan was delicious. I was expecting something tart but was delightfully surprised by the sweetness. Wish I had crackers to have spread it upon. Now the crust was perhaps the most unorthodox for anyone who has made a Cobbler. I saw a recipe online that used yellow cake mix; drenched in melted butter, as the crust. That appealed to my culinary laziness. But it worked. There was enough filling and cake-mix to make two cobblers that day. Ah...fun times. I am happy to conclude my recollection by stating my culinary experiment of three years ago was a delectable success.
  17. To an extent. A post by WolfOdrade on Stack Exchange's Science Fiction and Fantasy entitled "In the Dune series, why are they not using computers and programming related technologies?" states that in the original Dune, basic computer systems would be legal so long as they do not emulate the human mind.
  18. I was wondering if my understanding of an analog Absolute Magnetic Encoder is sound. In a project this last semester we used such a sensor for a wind vane. The signal output range was between 0 volts and 5 volts. As the encoder rotated through 360 degrees the voltage would increase to the maximum output and then reset to zero. While that was easy to understand the relationship between voltage and position, the data sheet never made clear as to how the sensor was generating the signal. But the project also had us working with Hall Effect sensors, which had me thinking. The magnitude of Hall Voltage, Vh, is directly proportional to the magnetic flux acting on the conductor of the sensor. Thus is is safe to assume that it is the magnetic flux that is changing as encoder rotates, and in turn, causes the change in the voltage signal of the encoder?
  19. I was speaking with someone who works at a company that uses Ferrofluid as the seal for vacuum chambers among other things. While my knowledge of this type of material is extremely limited, the fact it is used for applications at zero atmosphere suggests using ferrofluid could accomplish your airlock concept.
  20. Granted. However the Kerbal Space Center is set up in your hometown. Due to the Kerbal's penchant for unscheduled spacecraft disassembly and catastrophic failures, your hometown soon becomes a cratered ruin. I wish for that KSP is returned to it's computer realm so Robonoise's town will no long be destroyed.
  21. Granted. You received coins made from a 0.3 mm drill bit, but how this profits you is anyone's guess. I wish for a cure to a sore throat.
  22. Granted. You sense the speech is over. However you realize that this is only so because you've gone deaf. I've lost my hat. So I wish for a new hat.
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