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#700
by
dustinthewind
on 03 Aug, 2017 07:01
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Rodal, since I'm talking about the production of gravitational radiation, I'm referring to distributions of mass/energy in 3d.
The terminology is the same in General Relativity. It has to do with the intersection of rays emanating from the inside into a ball's spherical surface producing "poles" on the spherical surface. It is the same terminology used by Thibault Damour, one of the main people in GR (responsible for the 3PN, and 4PN, for gravitational waves from compact binary systems, and with Alessandra Buonanno, he invented the "effective one-body" approach to solving the orbital trajectories of binary black holes.) who attributes the terminology to Maxwell, originally for electromagnetic waves.
Same terminology for quadrupoles used by Kip Thorne and everybody in General Relativity
Here is a drawing of a quadrupole gravitational wave:
By the way, according to Einstein's General Relativity the minimum number of poles for a gravitational wave is 4 (quadrupole).
However, scalar tensor theories may allow for monopole gravitational waves (which are heretofore undetected).
Here they show the radiation pattern of the quadrupole as being two bowls together instead of being four lobes which I thought was interesting. Also they mention the similarity of magnetic dipole radiation to that of electric quadrupole radiation.
This result is similar to Eq. 9.48, indicating that electric quadrupole and magnetic dipole radiation have the same basic strength.
Similar to this image here:
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#701
by
Mulletron
on 03 Aug, 2017 13:09
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Rodal et al, what I'm trying to communicate to you is that the entire frustum (not the electric multipoles of any single mode being excited), and the shaped contents (because it's cone, not a symmetric cylinder) therein, amounts to one big time varying octupole (when viewed longitudinally), which according to what I've studied is fully capable of emitting gravitational radiation. Going back to the gravitational induction equation, the gravitational EMF produced would be dependent on the rate of change of flux in time, and the disturbance in spacetime would propagate as a disturbance of spacetime itself, as a wave. From what I've read, a gravitational wave rocket would do no better than a photon rocket, but an EmDrive is reported to outperform a photon rocket; my intuition tells me that the "fast switching" (talking about the gravitational equivalent of db/dt) within the cavity could be responsible for the anomalous performance.
Interesting discussion of this in an astrophysical setting on page 14 here:
http://www.drrobertbaker.com/docs/War%20on%20Terror%20Applications.pdfhttp://slideplayer.com/slide/5158008/While there's been plenty of attention to astrophysical sources of gravitational radiation, I see no reason to write off the production of such radiation in a lab setting. We're producing (very weak) gravitational waves all the time, and this is echoed here.
http://backreaction.blogspot.com/2016/02/everything-you-need-to-know-about.html
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#702
by
Monomorphic
on 03 Aug, 2017 14:23
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Dynamite. I'm planning on attending the NIAC Symposium. I hope to see you and others there.
I was able to talk my better half into making a long weekend trip out of it, so I plan on attending. It will be good to see you again Bob and to meet the gang!
Dr. Rodal, I didn't see a schedule. Do you know what day and time your group will be presenting? Please let me know.
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#703
by
Monomorphic
on 03 Aug, 2017 14:37
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I finished the 3D parts for printing the side walls. The cone angle is well within what the printer can print without needing supports. As with the end-plates, I split the side walls into four identical top and bottom quarters. I've also included images of what the completed frustum looks like including a cutaway.
All the parts are now complete and I've double checked that TE013 is at ~2.405GHz using the same mesh exported to FEKO. If there is interest, I can collect all the STL files and gcode for the parts and put them on Thingiverse.
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#704
by
Rodal
on 03 Aug, 2017 17:06
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Dynamite. I'm planning on attending the NIAC Symposium. I hope to see you and others there.
I was able to talk my better half into making a long weekend trip out of it, so I plan on attending. It will be good to see you again Bob and to meet the gang!
Dr. Rodal, I didn't see a schedule. Do you know what day and time your group will be presenting? Please let me know.
The schedule has not been disclosed yet. Judging from last year, the time allowed for each presentation is short: ~15 minutes, and there will be some time for questions and answers. Heidi will be making the presentation. Here is video for the last couple of years so that you can have a better idea of what to expect:
2016 Raleigh NC
https://livestream.com/viewnow/NIAC20162015 Seattle, WA
https://livestream.com/viewnow/NIAC2015It will be live broadcasted through livestream.com
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#705
by
Bob012345
on 03 Aug, 2017 18:00
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I finished the 3D parts for printing the side walls. The cone angle is well within what the printer can print without needing supports. As with the end-plates, I split the side walls into four identical top and bottom quarters. I've also included images of what the completed frustum looks like including a cutaway.
All the parts are now complete and I've double checked that TE013 is at ~2.405GHz using the same mesh exported to FEKO. If there is interest, I can collect all the STL files and gcode for the parts and put them on Thingiverse.
Great work! Do you think you will someday build a Cannae type device also? Anyone else here working on Cannae devices?
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#706
by
Monomorphic
on 03 Aug, 2017 21:13
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Do you think you will someday build a Cannae type device also? Anyone else here working on Cannae devices?
I don't have any plans to work on a Cannae drive at this time. I'm not aware of anyone working on duplicating Cannae's work either.
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#707
by
jpo234
on 03 Aug, 2017 22:08
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#708
by
SteveD
on 04 Aug, 2017 04:51
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All the parts are now complete and I've double checked that TE013 is at ~2.405GHz using the same mesh exported to FEKO. If there is interest, I can collect all the STL files and gcode for the parts and put them on Thingiverse.
Please do. The Fall semester is about to start. Replications by advanced undergrad or grad students is likely to be helpful in building support for EMDrive research. Making files available would help speed this process. Though I am worried about earlier reports that indicated rf should not be injected from the small base.
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#709
by
RotoSequence
on 04 Aug, 2017 05:07
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#710
by
tchernik
on 04 Aug, 2017 05:18
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I'm seeing "Overview of Electric Propulsion Developments at TU Dresden for Micro and Small-Satellites"
Did the title change?
It seems there are two papers being presented by Dr. Tajmar on this year's IAC, one with the intriguing title referring to The SpaceDrive project and the other much more conventional with the title you refer.
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#711
by
Mulletron
on 04 Aug, 2017 13:53
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Interesting lead here. I remember bringing up the notion of "jerk" before.
https://www.google.com/patents/US6417597
d2ω/dt2=second time derivative of the spindle's angular velocity, ω, or third time derivative of it's angle, termed, a “jerk”. In fact, as noted by M. S. Turner and R. V. Wagoner “Gravitational Radiation from Slowly Rotating ‘Supernova’ Preliminary Results,” in Sources of Gravitational Radiation, Edited by L. L. Smarr, Cambridge University Press , 1979, p. 383 that “If the angular velocity ω . . . is non-uniform, octupole (post-Newtonian) radiation is generated (in addition to the quadrupole (Newtonian) radiation . . . ” (emphasis added) and on p. 385 they state “This radiation is generated not by non-spherical distribution of matter . . . , but by internal motions.”So for instance, imagine you're in a race car, traveling around a track that is a perfect circle. You would feel a constant acceleration, but no jerk. Now imagine you're traveling around an egg shaped track, you would feel non-uniform acceleration as you make the turns.
http://dynref.engr.illinois.edu/avt.htmlEdit:
added:
Looks pretty "jerky".
https://forum.nasaspaceflight.com/index.php?topic=41732.msg1627599#msg1627599
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#712
by
Bob Woods
on 04 Aug, 2017 14:33
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#713
by
Eusa
on 05 Aug, 2017 09:16
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I noticed common principles between McCulloch's quantized inertia and my hypothesis concerning to the equivalency between space as massless radiation and matter as massive fields:
Σp(st_r) = nh/Σλ(st_r) = Σm(st_m)*c | in energetic closed spacetime section consisting st_r (radiation) and st_m (matter).
Σm(st_m)*c is intristic inner mass momentum of the matter in respect of free fall inertial frame and Σλ(st_r) is the sum of all massless quanta wavelengths, n is the amount of quanta.
Of course, all partial energetic closed spacetime sections are spatially "hairy" or intristic highly curved - the equation applies best for the whole universe.
The conclusion of that hypothesis is: massive matter gravitates, massless radiation not. Photons at emissions and at absorptions are part of massive matter structure.
Then, if you produced big amount of quanta massless radiation you could produce little extra space. If this process was asymmetric maybe you could produce little thrust too...
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#714
by
Monomorphic
on 05 Aug, 2017 13:09
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32 hours and 20 minutes of printing for one-quarter set of sidewalls.
A pretty intense thunderstorm rolled through during the last 5% of printing that made me very nervous. The power went out a couple of times, but the uninterruptible power supply did its job. I should be able to print for up to an hour before the battery is exhausted. And 99% of the time, power is restored almost immediately, so this should work out just fine.
I think I can adjust the settings of the printer to get each set finished in 19 hours with only a little loss in print resolution, but I really like the quality of the current settings a lot. Current settings are 0.15mm layers. I want to see if 0.2mm is noticeably different. 0.35mm layers is possible. The end-plates were printed using 0.05mm layers, the finest quality setting available.
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#715
by
WarpTech
on 05 Aug, 2017 16:03
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32 hours and 20 minutes of printing for one-quarter set of sidewalls. A pretty intense thunderstorm rolled through during the last 5% of printing that made me very nervous. The power went out a couple of times, but the uninterruptible power supply did its job. I should be able to print for up to an hour before the battery is exhausted. And 99% of the time, power is restored almost immediately, so this should work out just fine.
I think I can adjust the settings of the printer to get each set finished in 19 hours with only a little loss in print resolution, but I really like the quality of the current settings a lot. Current settings are 0.15mm layers. I want to see if 0.2mm is noticeably different. 0.35mm layers is possible. The end-plates were printed using 0.05mm layers, the finest quality setting available.
Very cool!
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#716
by
glennfish
on 06 Aug, 2017 23:37
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32 hours and 20 minutes of printing for one-quarter set of sidewalls. A pretty intense thunderstorm rolled through during the last 5% of printing that made me very nervous. The power went out a couple of times, but the uninterruptible power supply did its job. I should be able to print for up to an hour before the battery is exhausted. And 99% of the time, power is restored almost immediately, so this should work out just fine.
I think I can adjust the settings of the printer to get each set finished in 19 hours with only a little loss in print resolution, but I really like the quality of the current settings a lot. Current settings are 0.15mm layers. I want to see if 0.2mm is noticeably different. 0.35mm layers is possible. The end-plates were printed using 0.05mm layers, the finest quality setting available.
Questions?
What is the specific material being used?
How do you plan to coat it, and with what? In my mind's eye, I'd pop this into a vacuum chamber after fabrication and do a sliver coat through sublimation, followed by an aluminum coat through sputtering. Aluminum only to prevent oxidation. Not sure about copper.... you could do a copper plate chemically.
Is there any modeling available that indicates that 0.05mm is comparable to a copper plate which would have a smoothness off the rolling press of typically 100 microns?
Just curious. Answers not required.
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#717
by
spupeng7
on 07 Aug, 2017 01:44
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(...) Do you think you will someday build a Cannae type device also? Anyone else here working on Cannae devices?
Great question Bob012345,
if Guido Fetta's results are em thrust then there must be longitudonal asymetry in his lobes and it would be nice to know exactly how they are arranged.
Presuming that the design idea came from a working knowlege of linear particle accelerators, somone familiar with that technology might be able to get some good results.
My question is, can a Fetta type resonator be constructed that would resonate at 60 GHz and what would the dimensions of its lobes be?
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#718
by
Monomorphic
on 07 Aug, 2017 15:30
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What is the specific material being used?
How do you plan to coat it, and with what? In my mind's eye, I'd pop this into a vacuum chamber after fabrication and do a sliver coat through sublimation, followed by an aluminum coat through sputtering. Aluminum only to prevent oxidation. Not sure about copper.... you could do a copper plate chemically.
Is there any modeling available that indicates that 0.05mm is comparable to a copper plate which would have a smoothness off the rolling press of typically 100 microns?
Base material is PLA (Polylactic acid).
Initially, the end-plates will be covered with single pieces of copper foil. I will use an adhesive to bind the copper to the PLA. The interior surface of the side walls will be covered in overlapping 3 inch strips of EMI shielding copper adhesive foil. The conductive adhesive is pressure sensitive, so the harder the pieces are pressed together, the lower the resistivity. This is because conductivity is achieved via small flakes of metal suspended in the acrylic adhesive. When pressed together, these metal flakes make physical contact between the pieces of foil. I've used this method on the current flat end-plate frustum.
0.05mm is 50 micrometers. I am also lightly sanding the parts so they are smooth. There is a way to smooth the PLA using acetone, but I've not tried that.
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#719
by
rhubley
on 07 Aug, 2017 17:07
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Initially, the end-plates will be covered with single pieces of copper foil. I will use an adhesive to bind the copper to the PLA.
Are you not worried the heat generated by the frustum warping the PLA scaffold?
A pretty intense thunderstorm rolled through during the last 5% of printing that made me very nervous. The power went out a couple of times, but the uninterruptible power supply did its job. I should be able to print for up to an hour before the battery is exhausted. And 99% of the time, power is restored almost immediately, so this should work out just fine.