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#1120
by
X_RaY
on 10 Apr, 2016 21:11
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Thanks X_Ray, ---am glad it rings at some frequency... am still in a quandary about this though: I clearly recall " if you reduce the dimensions by 10 then you increase the frequency by 10" So if we scaled down frustum X by a factor of ten, then we must increase the frequency by a factor of ten. Therefore a frustum that rings best at 2.45 GHz will ring best at 24.5 GHz if the frustum scaled down by a factor of ten. IS THIS NOT COORECT? OR?
Due to the linearity of the Maxwell equations that's absolutely correct, if you scale down all dimensions of the frustum by a factor of 10 the resonant frequency for the same mode will be exact 10 times higher in frequency.
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#1121
by
Rodal
on 10 Apr, 2016 21:13
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Thanks X_Ray, ---am glad it rings at some frequency... am still in a quandary about this though: I clearly recall " if you reduce the dimensions by 10 then you increase the frequency by 10" So if we scaled down frustum X by a factor of ten, then we must increase the frequency by a factor of ten. Therefore a frustum that rings best at 2.45 GHz will ring best at 24.5 GHz if the frustum scaled down by a factor of ten. IS THIS NOT COORECT? OR?
Yes from the point of view of frequency and mode shape.
No for ringing.
You state " frustum that rings best "
rings best has to do with quality of resonance "Q", and to maximize Q, you have to have a frustum as large as possible. When you scale it down, you are lowering the quality of resonance Q,
everything else being the same.
See:
https://forum.nasaspaceflight.com/index.php?topic=39214.msg1474347#msg1474347The quality of resonance (Q) scales like the square root of any geometrical dimension, for constant resistivity and magnetic permeability of the interior wall of the cavity and for constant geometrical ratios, constant medium properties μr,εr, and for the same mode shape m,n,p.
Therefore when you scale it down it will ring with the same mode shape at a higher frequency, but it will not ring for as long a time.
When you scale it down it will not "ring best" compared to the larger size.
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#1122
by
Monomorphic
on 10 Apr, 2016 21:38
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This is pretty neat! Effects of tuning over bandwidth 2.42 Ghz - 2.48 Ghz to simulate a dirty ~2.45 Ghz magnetron with my frustum dimensions. I see I may have to tune as much as ~2+ cm to get TE311 as I intended.
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#1123
by
FattyLumpkin
on 10 Apr, 2016 22:06
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Dr. Rodal, therefore to resonate best is the operative word. Is there any method to calculate where the best frequency for resonating is in a scaled down frustum? In this instance (as is known) the frequency for the large NASA frustum is 1.8804 GHz, TE012 mode. Up scaling of the frequency by the same amount which is .2794 to achieve the bottom diameter of 10 cm to accommodate Cudesat dimensions would change the frequency to 5.2538 GHz. (I believe). Yet this my not be the "best" frequency for resonance. Correct?
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#1124
by
Rodal
on 10 Apr, 2016 22:53
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Dr. Rodal, therefore to resonate best is the operative word. Is there any method to calculate where the best frequency for resonating is in a scaled down frustum? In this instance (as is known) the frequency for the large NASA frustum is 1.8804 GHz, TE012 mode. Up scaling of the frequency by the same amount which is .2794 to achieve the bottom diameter of 10 cm to accommodate Cudesat dimensions would change the frequency to 5.2538 GHz. (I believe). Yet this my not be the "best" frequency for resonance. Correct?
It depends on what "best" means. The Q of a low TE mode is among the highest. So you are on the right track with TE012. It is the same mode shape that Shawyer claims for the Demonstrator and Yang for her experiments. Yet TheTraveller recommends TE013, which also makes sense to me because TE013 has the peak of energy density located near the small end. But, regarding "thrust" all bets are off until somebody proves without a doubt that there is thrust and proves the reason for it.
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#1125
by
SeeShells
on 10 Apr, 2016 23:09
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This is pretty neat! Effects of tuning over bandwidth 2.42 Ghz - 2.48 Ghz to simulate a dirty ~2.45 Ghz magnetron with my frustum dimensions. I see I may have to tune as much as ~2+ cm to get TE311 as I intended.
Power your Magnetron with a clean DC source and narrow the BW output.
Shell
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#1126
by
Monomorphic
on 10 Apr, 2016 23:52
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Power your Magnetron with a clean DC source and narrow the BW output.
Which one are you using? Hopefully it's not too $$$.
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#1127
by
SeeShells
on 10 Apr, 2016 23:55
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#1128
by
Monomorphic
on 11 Apr, 2016 01:28
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Nothing like a fresh paint job!
All soldering finished. Exterior painted with high temp flat black. Silicone conformal coating on the interior.
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#1129
by
FattyLumpkin
on 11 Apr, 2016 02:04
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Shell and Morphic, please don't forget if you y'all get stuck and need a $ contribution I'd be glad to help.
On another subject though I got an idea (Uh-oh!)--no, this is a good one: I looked around for what ever I could find re EWL simulations and couldn't find a sim of any of what is published in EM drive experimental results.
Therefore, X_Ray and or Monomorphic do you care to do a sim on this purported best EWL result:
NASA Brady, White, March, Lawrence, and Davies:
mode TE012, Height=0.2286m, BD=0.2794m, SD=0.15875m, GHz 1.8804, 2.6 Watts (dielectric from the top)
Of course if one has been done and someone can steer me to it, I'd be much obliged!
FL
PS: I find it entertaining to check-up on teacher's homework ..hehehe (can't find emoji will horns and fork tail)
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#1130
by
Rodal
on 11 Apr, 2016 03:20
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Shell and Morphic, please don't forget if you y'all get stuck and need a $ contribution I'd be glad to help.
On another subject though I got an idea (Uh-oh!)--no, this is a good one: I looked around for what ever I could find re EWL simulations and couldn't find a sim of any of what is published in EM drive experimental results.
Therefore, X_Ray and or Monomorphic do you care to do a sim on this purported best EWL result:
NASA Brady, White, March, Lawrence, and Davies:
mode TE012, Height=0.2286m, BD=0.2794m, SD=0.15875m, GHz 1.8804, 2.6 Watts (dielectric from the top)
Of course if one has been done and someone can steer me to it, I'd be much obliged! FL
PS: I find it entertaining to check-up on teacher's homework ..hehehe (can't find emoji will horns and fork tail)
I showed in previous threads a comparison of those images you attached (which is mode shape TM212, not TE012) with an exact solution for the problem, using Wolfram Mathematica. I posted the magnetic fields, the electric fields and the Poynting vector fields.
The exact solution matches excellently with NASA's results.
Sorry it is difficult to find the posts due to the Search function at NSF, but if all you wanted to know is whether NASA's solution for the images you attached had been independently verified, the answer is yes, it has been verified.
NASA's COMSOL FEA:
EXACT SOLUTION USING WOLFRAM MATHEMATICA:
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#1131
by
X_RaY
on 11 Apr, 2016 06:09
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Millisecond Photon Lifetime in a Slow-Light Microcavity
V. Huet, A. Rasoloniaina, P. Guillemé, P. Rochard, P. Féron, M. Mortier, A. Levenson, K. Bencheikh, A. Yacomotti, and Y. Dumeige
Phys. Rev. Lett. 116, 133902 – Published 29 March 2016
Optical microcavities with ultralong photon storage times are of central importance for integrated nanophotonics. To date, record quality (pctors up to 1011 have been measured in millimetric-size single-crystal whispering-gallery-mode (WGM) resonators, and 1010 in silica or glass microresonators. We show that, by introducing slow-light effects in an active WGM microresonator, it is possible to enhance the photon lifetime by several orders of magnitude, thus circumventing both fabrication imperfections and residual absorption. The slow-light effect is obtained from coherent population oscillations in an erbium-doped fluoride glass microsphere, producing strong dispersion of the WGM (group index ng∼106). As a result, a photon lifetime up to 2.5 ms at room temperature has been measured, corresponding to a Q factor of 3×1012 at 1530 nm. This system could yield a new type of optical memory microarray with ultralong storage times.
Interesting and surprising! One would expect that losses are a dominant effect.
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#1132
by
Eusa
on 11 Apr, 2016 08:45
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Millisecond Photon Lifetime in a Slow-Light Microcavity
V. Huet, A. Rasoloniaina, P. Guillemé, P. Rochard, P. Féron, M. Mortier, A. Levenson, K. Bencheikh, A. Yacomotti, and Y. Dumeige
Phys. Rev. Lett. 116, 133902 – Published 29 March 2016
Optical microcavities with ultralong photon storage times are of central importance for integrated nanophotonics. To date, record quality (pctors up to 1011 have been measured in millimetric-size single-crystal whispering-gallery-mode (WGM) resonators, and 1010 in silica or glass microresonators. We show that, by introducing slow-light effects in an active WGM microresonator, it is possible to enhance the photon lifetime by several orders of magnitude, thus circumventing both fabrication imperfections and residual absorption. The slow-light effect is obtained from coherent population oscillations in an erbium-doped fluoride glass microsphere, producing strong dispersion of the WGM (group index ng∼106). As a result, a photon lifetime up to 2.5 ms at room temperature has been measured, corresponding to a Q factor of 3×1012 at 1530 nm. This system could yield a new type of optical memory microarray with ultralong storage times.
Interesting and surprising! One would expect that losses are a dominant effect.
Great.
Now we need only get those optical cavities in the form of fan to guide vacuum quanta for warping spacetime and thrusting without propellant. (
)
I think a gravitational drive is worth of testing with TE modes and monochromatic but also with many kinds of radiation. If the phenomenon is due to gravitational warping, there is no need to use harmful microwaves, other than maybe the controlling accuracy for resonance...
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#1133
by
Chrochne
on 11 Apr, 2016 12:08
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Dont know what to follow more. Here EmDrive or that Nassikas Superconducting Lorentz Thruster. (
https://www.indiegogo.com/projects/superconducting-levitation-thruster#/)
In recent months there are so many new type of thrusters. Way to go
!
I checked that it got beating here on NSF by Dr. Rodal and Zen-In. Still quite interesting reading.
Star-Track and Star Wars fans you might want to chech that out!
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#1134
by
rfmwguy
on 11 Apr, 2016 14:07
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Dont know what to follow more. Here EmDrive or that Nassikas Superconducting Lorentz Thruster. (https://www.indiegogo.com/projects/superconducting-levitation-thruster#/)
In recent months there are so many new type of thrusters. Way to go !
I checked that it got beating here on NSF by Dr. Rodal and Zen-In. Still quite interesting reading.
Star-Track and Star Wars fans you might want to chech that out!
Am proud of emdrive topic posters that addressed those claims. One other nsf poster...not so much. I would have liked to have seen more direct addressing of specific questions asked of the inventors, but this is likely the first time they have had such a rigorous discussion in a public forum.
The topic might live, or it might close with questions left unanswered...either way...if it is meant to take off, it will. If not, C'est la vie.
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#1135
by
rfmwguy
on 11 Apr, 2016 14:16
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Somewhere, a few weeks ago, we missed a major milestone: 5 million views of EMDrive T1-T7
Today, we are at 5205182 views total across 7 threads.
For such an "obscure" and technical topic, I think it demonstrates the level of interest in the device; a potential revolution is deep space exploration.
Good job to all contributors for keeping it relevant and interesting.
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#1136
by
Rodal
on 11 Apr, 2016 16:34
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What is your opinion of Trunov's paper on the EM Drive, also involving general relativity ?
See attachment (I enclose the English language version. There is also an original Russian version if you find that language easier to read)
GENERAL RELATIVITY AND DYNAMICAL MODEL OF ELECTROMAGNETIC DRIVE
Трунев Александр Петровичк.ф.-м.н., Ph.D., директор
Alexander Trunev
Cand.Phys.-Math.Sci., Ph.D., C.E.O.
Научный журнал КубГАУ, №116(02), 2016 года
I have absolutely no russian language skills.
I noticed at glance that the claim is mass-reducing - my claim is space-reducing and hence the increace of apparent non-inertial mass.
Maybe this difference is due to my understanding that space fragments are streaming to masses, there are no pulling force signals from gravitating body. The gradient of space tension of vacuum quanta affect accelerations.
Another paper using gravitation relativity (this time using a scalar-tensor theory) to justify the claims of anomalous force for the EM Drive is the one by Minotti, published in the more prestigious peer-reviewed journal Grav. & Cosmol:
Scalar-tensor theories and asymmetric resonant cavitiesFernando O. Minotti
Grav. & Cosmol. 19 (2013) 201
DOI: 10.1134/S0202289313030080
http://arxiv.org/abs/1302.5690The problem with the theory is that it leads to gravitational effect due to magnetism that are dissonant with measurements around the Earth's magnetic field. Minotti proposes that a nonlinear theory may address this discrepancy. Minotti does an excellent job (compared to other authors) of discussing the exact solution for the electromagnetic fields in the truncated cone cavity.
Please let us know what you think of this paper vis-a-vis your theory.
(Minotti is an Italo-Argentinean but you don't need to know neither Italian nor Spanish to read this one, which is in English in its published form
)
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#1137
by
rfmwguy
on 11 Apr, 2016 17:21
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Casimir Effect studies by an important nuclear physics lab in Italy using Microwave cavities and parametric amplifiers.
This energy effect could possibly relate to the EMDrive. The cavity resonant frequency is 2.5 GHz. Similarity is more than interesting from my "theory-less" perspective.
The 2014 public powerpoint is attached below. It is called the Mir Experiment by Legnaro National Laboratories (LNL):
http://www.lnl.infn.it/index.php/en/A direct study of emdrive by a physics lab? No, but a deep look into the Casimir force...potentially related.
Their
Quantum Vacuum discussion page:
http://www.lnl.infn.it/index.php/en/researchbutton-3/physics-without-accelerator
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#1138
by
FattyLumpkin
on 11 Apr, 2016 19:07
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rfmwguy, any scuttle(butt) re the EWL paper now in review? Is it known if EW attempts to explain a theory, or is it a report on materials methods with the given results?
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#1139
by
rfmwguy
on 11 Apr, 2016 19:20
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rfmwguy, any scuttle(butt) re the EWL paper now in review? Is it known if EW attempts to explain a theory, or is it a report on materials methods with the given results?
No idea FL...its likely taking time for all the reviewers to reach a consensus. Any one of them could ask for more information and details either on theory or the experiment itself. They won't put their name on something unless they have 100% confidence.
All speculation, but a likely scenario. One thing for certain, it was not a quick reject... if that helps.
FL
)
!
)