I did notice that the file type had changed from the .png (portable network graphics) I sent (I think) to a .jpg (IIRC). Could that conversion have reduced it?MSimon wrote:It probably has to do with how you saved them. You need more dots.
Usually it has to do with the format you save it in. I have never had a problem with that conversion before. It is also possible that Photobucket has installed a "new feature" which shrinks oversize files. Check the Photobucket file size vs your file size. Then check their maximum pixel count and framing.KitemanSA wrote:I did notice that the file type had changed from the .png (portable network graphics) I sent (I think) to a .jpg (IIRC). Could that conversion have reduced it?MSimon wrote:It probably has to do with how you saved them. You need more dots.
Anyway, I think I will just go ahead and get a photobucket account. Thank you for your support.
KitemanSA wrote:Please remember that Dr. B had envisioned that the final coils would be either square or pentagonal in plan-form (not cross section, plan-form)with rounded corners. I think this will tend to reduce the overall stresses in the magnet because the coil and virtual coils forces will be better balanced. With the "straight" sides of the coil actually following a "great circle" along the sphere of the well rather than the edges of the cuboctohedron, the primary forces might resolve into simple hoop stresses in most of the magnet.
Unfortunately, my sketch shows the same error asBilly Catringer wrote: Need picture! I think I understand, but I need to see a sketch or something before I can say for sure.
did here. But if you mentally grow the plan-form till it reaches the edges of the cuboctohedron while making the corners round enough to avoid each other, you almost have it. One step further. The sides of his square plan form have a kink in them. Make them curved to fit the spherical surface and voila!hanelyp wrote:An image I posted to the magrid brainstorming thread:
Same basic config as the cube polywell, but with the coils bent to be more 'spherical'. Is this something like what you're trying to get at?
I could wind either a standard strand OR quasi-bitter plate magnet in this shape... in copper, and winding with AMSC Gen2 wire would be possible, but a LOT tougher. But assuring appropriate slack or tension to pre-adjust for shrinkage would be much more difficult.Billy Catringer wrote:A structure like this could be built, but there are several problems with it.
1) How do you wind the coils? If winding coils in this shape is not possible, can a Bitter Plate type of magnet be made in this shape?
If you want them in compression (I suspect you mean you want to squeeze the wires, not push on them) then you would have to transfer the outward loads into a trough which would handle it in tension.2) Assuming one or the other such cores can be made, how do we support it against the stresses that will be applied to it. We want those brittle cores in compression, not tension, shear or torsion.
Actually this may be a good thing because it should be easier to wind with a bit of slack than wind with a controlled extra taughtness.3) The strands of the SC core contract along their lengths more than they contract in any other direction as they chill. This will put a lot of stress on the strands of the winding no matter what the shape of the core and this shape will likely cause them to develp stresses unevenly.
Simple engineering ....ha ha ha ha ha ha ha ha4) It's necessary to pump lots and lots of cooling water through two separate jackets to keep the heat from reaching the superconducting core. The more twists and turns there are in the way of the water, the more friction there is and there will be an increase in the tendency for the structural system to vibrate. Even without the kinks shown in this sketch, the flow of water will be impeded by the additional turns it will have to make. Vibration is going to be hard to avoid with the simpler toroii.
Simple engineering ....he he he he ha ha haAs far as I can tell, and someone correct me if I am wrong, the SC core will be brittle at LHe temperatures. That means that the support of the SC cores must be as firm and rigid as the foundation of a masonry building. If the structure deforms even a little, the cores will crack or spall and that would lead to a complete failure under load, or the danged things will break sometime during cool down. The entire system will shrink while the two inner coolant loops are filled with LHe and LN2.
As far as I can tell, and someone correct me if I am wrong, the SC core will be brittle at LHe temperatures.
In theory - lots of people like NaK. In practice - not so much.Personally, I kind of like the idea of using NaK for the first loop.
MSimon wrote:As far as I can tell, and someone correct me if I am wrong, the SC core will be brittle at LHe temperatures.
MgB helps. The ceramic superconductors not so much.
In any case there are companies with experience in this sort of design. We hire them or hire away one of their designers. Or put out a help wanted ad. The economy may provide some useful talent.
Your list of coolant Ts and flows show the outside coolant loop to by H2O at about 600C, no? Pressurizing that will be a bear, unless you mean steam, and it doesn't carry much heat away. The NaK will allow those temps without the Ps. Just a thouht.MSimon wrote:In theory - lots of people like NaK. In practice - not so much.Personally, I kind of like the idea of using NaK for the first loop.
At this point there is no definite temperature the first shield has to run at. It is only the delta T that is important. All higher Ts get you in an experimental reactor is a smaller radiator.
Power extraction may change that equation. However, there is no reason to make EVERYTHING hard for the experiments.
200C would work just as well for cooling. If the 100C delta T was not a problem at that temp. In fact 50C to 150C (inlet vs outlet) would be fine for a test reactor. There is nothing magic about 600C (at least in the experimental version).KitemanSA wrote:Your list of coolant Ts and flows show the outside coolant loop to by H2O at about 600C, no? Pressurizing that will be a bear, unless you mean steam, and it doesn't carry much heat away. The NaK will allow those temps without the Ps. Just a thouht.MSimon wrote:In theory - lots of people like NaK. In practice - not so much.Personally, I kind of like the idea of using NaK for the first loop.
At this point there is no definite temperature the first shield has to run at. It is only the delta T that is important. All higher Ts get you in an experimental reactor is a smaller radiator.
Power extraction may change that equation. However, there is no reason to make EVERYTHING hard for the experiments.
I said "If you want them in compression (I suspect you mean you want to squeeze the wires, not push on them) then you would have to transfer the outward loads into a trough which would handle it in tension." I presumed you would understand that the trough would be on the outward face of the great-circle parts of the loop. Indeed the main loads will be at the corners of the loops where they must connect across to the next loop (or outward to a strength frame).Billy Catringer wrote:It's hard to explain what I mean by compression without drawing you the pictures I am working on right now, but I'll try. Because the magnetic array is essentially symmetrical, and all of its elements are symmetrical, the resultants of all the forces acting on them are pushing outwards from the center of the array, acting through the magnetic centers of the the torii. So long as the magnets are powered up, these resultant forces are dominant, gravity counts for very little.
True, all true.The job of the structure is to counter those resultants while keeping an even load on the SC cores. Strangely enough, this is the easy part. The hard part is accommodating all the other stuff that happens prior to charging while dealing with cool down and then the sudden heating once fusion starts. Shear, torque and tensions stresses have to be kept off the core while all those things are ongoing. Oh, and until the magnets are charged, gravity is a problem. The cores must be trapped so that they do not impose shear stresses on themselvs while fighting gravity.
Is this in reference to the two phase coolant? Always a hassle, but excellent in concept!All of this can be done, but it is expensive. Also, you don't want to overtake the plumbing. It's too easy to plug the drain when ya do tha.
