Author Topic: EM Drive Developments Thread 1  (Read 1472555 times)

Offline Mulletron

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Re: EM Drive Developments
« Reply #3100 on: 11/10/2014 03:18 pm »
While in the shower, I realized that I am being drawn into a straw man argument about frequency, when my first assertions were about the measured "bounce" of the test article vs the cal system. Did I mention that we're not dealing with an already oscillating pendulum. The "noise" oscillations are clearly visible in the screenshot below, and the kinetic energy to be overcome from those oscillations is inconsequential because the table is isolated from the rest of the earth. (Gulf of Mexico, footsteps, and car crashes are isolated from measurement.) It is inconsequential because the "thrust" is clearly visible above the noise floor. No further treatment is required to suss that signal out.

Even after demonstrating one way, that is simple and elegant (the website) that a change of mass suspended from a pendulum does not affect the frequency. This was chosen to not confuse bystanders or using howlers. http://en.wikipedia.org/wiki/Mathematical_fallacy#Howlers. Such as using formulas below:
m d2x/dt2 +c dx/dt + k x = F(t)

Which should be this anyway: m (d2x/dt2)+c(dx/dt)+kx =F(t)

And introducing conditions which aren't present, such as an already oscillating pendulum.

That formula you posted above is a mass spring damper equation of an oscillator.

This isn't personal. Just practical perspective. We're not trying to pick out unclear signals from noise here, like it is SETI.
« Last Edit: 11/10/2014 03:28 pm by Mulletron »
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Offline Rodal

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Re: EM Drive Developments
« Reply #3101 on: 11/10/2014 03:28 pm »
While in the shower, I realized that I am being drawn into a straw man argument about frequency, when my first assertions were about the measured "bounce" of the test article vs the cal system. Did I mention that we're not dealing with an already oscillating pendulum. The "noise" oscillations are clearly visible in the screenshot below, and the kinetic energy to be overcome from those oscillations is inconsequential because the table is isolated from the rest of the earth. (Gulf of Mexico, footsteps, and car crashes are isolated from measurement.) It is inconsequential because the "thrust" is clearly visible above the noise floor. No further treatment is required to suss that signal out.

Even after demonstrating one way, that is simple and elegant (the website) that a change of mass suspended from a pendulum does not affect the frequency. This was chosen to not confuse bystanders or using howlers. http://en.wikipedia.org/wiki/Mathematical_fallacy#Howlers. Such as using formulas below:
m d2x/dt2 +c dx/dt + k x = F(t)

Which should be this anyway: m (d2x/dt2)+c(dx/dt)+kx =F(t)

And introducing conditions which aren't present, such as an already oscillating pendulum.

That formula you posted above is a mass spring damper equation of an oscillator.

Previously you posted that you "don't care about the pendulum frequency" in order to determine the dynamic response  :)

Now you post that "a change of mass suspended from a pendulum does not affect the frequency"  :)

And your statements about "an already oscillating pendulum"? as if the statements I posted before have anything to do with an already oscillating pendulum ?  :)

« Last Edit: 11/10/2014 03:32 pm by Rodal »

Offline Mulletron

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Re: EM Drive Developments
« Reply #3102 on: 11/10/2014 03:30 pm »
http://forum.nasaspaceflight.com/index.php?topic=29276.msg1286223#msg1286223

Nope.

You brought up frequency later and I told you I don't care about frequency.

I don't care about frequency because of the mass independence of pendulum period.
« Last Edit: 11/10/2014 03:38 pm by Mulletron »
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Offline Rodal

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Re: EM Drive Developments
« Reply #3103 on: 11/10/2014 03:34 pm »
http://forum.nasaspaceflight.com/index.php?topic=29276.msg1286223#msg1286223

Nope.

You brought up frequency and I told you I don't care about frequency.

I don't care about frequency because of the mass independence of pendulum period.

Now you are stating that the natural frequency of the NASA Eagleworks pendulum used for the "Anomalous " report does not depend on the mass?  :)   ::)
« Last Edit: 11/10/2014 03:38 pm by Rodal »

Offline Mulletron

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« Last Edit: 11/10/2014 03:48 pm by Mulletron »
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Offline Rodal

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Re: EM Drive Developments
« Reply #3105 on: 11/10/2014 03:49 pm »
http://ocw.mit.edu/high-school/physics/demonstrations-on-video/oscillations-gravitation/pendulum-periods/

46:30 in.

I'm not arguing anymore.

You have shown that you don't understand the dynamics of the NASA Eagleworks pendulum at all.

NASA Eagleworks for the "Abnormal ..." report that we are discussing on this EM Drive thread used a torsional pendulum. 

Read the title of the report we are discussing:  "Anomalous Thrust Production from an RF Test Device Measured on a Low-Thrust Torsion Pendulumhttp://www.libertariannews.org/wp-content/uploads/2014/07/AnomalousThrustProductionFromanRFTestDevice-BradyEtAl.pdf

The natural frequency of the pendulum that NASA Eagleworks used depends on the square root of the rotary moment of inertia and hence it depends on the square root of the mass.


It is not possible to understand the dynamics of the EM Drive measurement if one doesn't understand the dynamics of the torsional pendulum that the EM Drive is attached to.
« Last Edit: 11/10/2014 04:00 pm by Rodal »

Offline Ron Stahl

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Re: EM Drive Developments
« Reply #3106 on: 11/10/2014 04:04 pm »
What the author is discussing does not apply to the EM drives researched by NASA Eagleworks because the materials used are isotropic.  (Copper in all cases and in some cases Teflon or Polyethylene dielectrics -injection molded-)
IIRC, some of the cryogenically injection molded metal glass alloys are anisotropic as they align with strong fields when injection molded.  See the stuff at liquidmetal.com for this.  Additionally, there are ways to force anisotropy even on sputtered films of copper and the like.  Sputtering anisotropic films is a trade secret carefully guarded within its industry but it's something some people know how to do.  It's done with AiN on a daily basis.

Offline Ron Stahl

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Re: EM Drive Developments
« Reply #3107 on: 11/10/2014 04:10 pm »
Quote
The EM Drives tested by NASA Eagleworks do not satisfy the anisotropy  (mechanical and electromagnetic) conditions required by the author. What the author discusses is not applicable to explain the measurements at NASA Eagleworks.

@Mulletron - That does not mean necessarily that you're on the wrong track, just that our current understanding is not sufficiently complete to attribute the measured force. (I know, that sounds like gobbally-gook)  :)
There is a way to make these polymers anisotropic in bulk.  I read some years ago and just did a quick search, it concerns stretching the material.  There was some buzz years ago that the new electroactive polymers being considered for energy conversion and springwalker style powered armor benefit hugely from anisotropy.  Quick search came up with this if you have an interest I'm sure you can do a better one.

http://pubs.acs.org/doi/abs/10.1021/cm052511w
Well I accepted the challenge. It took me 30 minutes to find that both extruded PE and PTFE solidify to a semicrystalline structure. Therefore they are anisotropic. If they were amorphous, they'd be isotropic.

So I've established that the materials used in the the Brady et al test campaigns are both chiral polymers and they are both anisotropic due to their semicrystalline structure.

I'll save you the trip to the Oracle this time.
See for yourself. Just google crystallization of polymers.
Also google chiral polymer tacticity.

A neat resource I found:
https://www.nde-ed.org/EducationResources/CommunityCollege/Materials/Structure/anisotropy.htm

Also two exciting words: lamella twisting, here's helical chirality in PE
http://www.esrf.eu/UsersAndScience/Publications/Highlights/2011/scm/scm4

Chirality=proven true
mechanical anisotropy=proven true
electromagnetic or magnetic anisotropy=not proven true, this is where spontaneous pt symmetry breaking comes in. Been working on this one for a while.

Neither PTFE (Tefflon) or Polyethylene are mechanically or electromagnetically anisotropic in bulk.  I have measured their directional properties with Dielectrometry, NMR, TMA, DTMA and with MTS.  Semi crystallinity in thermoplastic polymers is not at all like well ordered crystalline metals.  The "crystalline" regions have independent domains oriented randomly throughout the polymer.  Extrusion anisotropy takes place at the exterior surface of the extruded rod in regions of very high shear near the extruder walls.  The interior of the extruded rod is isotropic.   Injection molded PTFE and PE are isotropic due to the random orientation produced during the injection molded process.

There are proprietary manufacturing methods to produce mechanically , electromagnetically and  optically anisotropic polymers, for example when making optically anisotropic polarized lenses.  One would not use extrusion to make such lenses.    It is much easier to attain preferred orientation, overall-anisotropic materials for thin polymer sheets or for very small diameter filaments.

Offline Rodal

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Re: EM Drive Developments
« Reply #3108 on: 11/10/2014 04:15 pm »
Quote
The EM Drives tested by NASA Eagleworks do not satisfy the anisotropy  (mechanical and electromagnetic) conditions required by the author. What the author discusses is not applicable to explain the measurements at NASA Eagleworks.

@Mulletron - That does not mean necessarily that you're on the wrong track, just that our current understanding is not sufficiently complete to attribute the measured force. (I know, that sounds like gobbally-gook)  :)
There is a way to make these polymers anisotropic in bulk.  I read some years ago and just did a quick search, it concerns stretching the material.  There was some buzz years ago that the new electroactive polymers being considered for energy conversion and springwalker style powered armor benefit hugely from anisotropy.  Quick search came up with this if you have an interest I'm sure you can do a better one.

http://pubs.acs.org/doi/abs/10.1021/cm052511w
Well I accepted the challenge. It took me 30 minutes to find that both extruded PE and PTFE solidify to a semicrystalline structure. Therefore they are anisotropic. If they were amorphous, they'd be isotropic.

So I've established that the materials used in the the Brady et al test campaigns are both chiral polymers and they are both anisotropic due to their semicrystalline structure.

I'll save you the trip to the Oracle this time.
See for yourself. Just google crystallization of polymers.
Also google chiral polymer tacticity.

A neat resource I found:
https://www.nde-ed.org/EducationResources/CommunityCollege/Materials/Structure/anisotropy.htm

Also two exciting words: lamella twisting, here's helical chirality in PE
http://www.esrf.eu/UsersAndScience/Publications/Highlights/2011/scm/scm4

Chirality=proven true
mechanical anisotropy=proven true
electromagnetic or magnetic anisotropy=not proven true, this is where spontaneous pt symmetry breaking comes in. Been working on this one for a while.

Neither PTFE (Tefflon) or Polyethylene are mechanically or electromagnetically anisotropic in bulk.  I have measured their directional properties with Dielectrometry, NMR, TMA, DTMA and with MTS.  Semi crystallinity in thermoplastic polymers is not at all like well ordered crystalline metals.  The "crystalline" regions have independent domains oriented randomly throughout the polymer.  Extrusion anisotropy takes place at the exterior surface of the extruded rod in regions of very high shear near the extruder walls.  The interior of the extruded rod is isotropic.   Injection molded PTFE and PE are isotropic due to the random orientation produced during the injection molded process.

There are proprietary manufacturing methods to produce mechanically , electromagnetically and  optically anisotropic polymers, for example when making optically anisotropic polarized lenses.  One would not use extrusion to make such lenses.    It is much easier to attain preferred orientation, overall-anisotropic materials for thin polymer sheets or for very small diameter filaments.

Stretching the polymer to produce semi-crystalline anisotropic polymers (something I was involved in my professional life in manufacturing, numerical analysis and R&D) works well for filaments and thin films.  Not for a thick polymer.  As an example, Kevlar is a liquid crystalline polymer.  To make strongly aligned, and fairly free of defects, one makes Kevlar fibers.  To make a thick aerospace product one may use a Kevlar-fiber reinforced composite but not a thick solid bulk Kevlar product (which doesn't exist for Kevlar because it would have undesirable poor properties for the reasons previously addressed).
« Last Edit: 11/10/2014 04:33 pm by Rodal »

Offline Ron Stahl

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Re: EM Drive Developments
« Reply #3109 on: 11/10/2014 04:17 pm »
No wait, this is reverse, we are not the paid researchers here. They should do the work of proving correctly this is not a thermal effect, then we could consider the possibility it is something less conventional. Unless they do prove this is not thermal, this is probably thermal and bogus indeed. We should not get habituated to this poor level of justifications. Because extraordinary claims...
Agreed but lets remember this is a conference paper, not a peer review paper, and they rushed to get to market with this, not even doing a statistically valid series of runs.  It is because of this though, that their funding was extended another 6 months, so not hard to understand.

It's science.  The truth will eventually win out regardless what ion drives are molested in the interim.

Offline Mulletron

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Re: EM Drive Developments
« Reply #3110 on: 11/10/2014 04:21 pm »
Even with the straw man, leading to a debate over frequency. One cannot make predictions about the dynamics of the test rig without knowing the masses of the pendulum or the test articles.
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Offline Ron Stahl

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Re: EM Drive Developments
« Reply #3111 on: 11/10/2014 04:33 pm »
Stretching the material to produce semi-crystalline anisotropic polymers (something I was involved in my professional life in manufacturing, numerical analysis and R&D) works well for filaments and thin films.  Not for a polymer several inches thick.  As an example, Kevlar is a liquid crystalline polymer.  To make strongly aligned, and fairly free of defects, one makes Kevlar fibers.  To make a thick aerospace product one may use a Kevlar-fiber reinforced composite but not a inches thick solid bulk Kevlar product (which doesn't exist because it is undesirable).
It was my understanding (and it's some years since I studied this) that these are all electrostrictors, not piezoactive; so not able to do power generation since electrostriction is not reversible.  (Also not rigid enough for VHF, UHF and microwave frequencies, so they're useless for M-E tech.)  So were you working on the polymer actuator powered personal armor from the old Springwalker/Land Warrior program?  That is such cool tech!
« Last Edit: 11/10/2014 04:47 pm by Ron Stahl »

Offline Rodal

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Re: EM Drive Developments
« Reply #3112 on: 11/10/2014 04:37 pm »
Stretching the material to produce semi-crystalline anisotropic polymers (something I was involved in my professional life in manufacturing, numerical analysis and R&D) works well for filaments and thin films.  Not for a polymer several inches thick.  As an example, Kevlar is a liquid crystalline polymer.  To make strongly aligned, and fairly free of defects, one makes Kevlar fibers.  To make a thick aerospace product one may use a Kevlar-fiber reinforced composite but not a inches thick solid bulk Kevlar product (which doesn't exist because it is undesirable).
I usually draw the distinction between thin films and bulk, but I'm sure you can draw the distinction between thick films and bulk if you like.

It was my understanding (and it's some years since I studied this) that these are all electrostrictors, not piezoactive; so not able to do power generation since electrostriction is not reversible.  (Also not rigid enough for VHF, UHF and microwave frequencies, so they're useless for M-E tech.)  So were you working on the polymer actuator powered personal armor from the old Springwalker/Land Warrior program?  That is such cool tech!

Rather than discussing our involvement in DoD projects, we better focus on the thread.  The discussion of anisotropy that you are referring to was motivated by Mulletron who has multiple posts advocating that the EM Drive measurements may be due to the Quantum Vacuum transferring momentum to the polymers used as a dielectric in the EM Drives.  (Specifically because of polymer chirality).

Is this (Quantum Vacuum transferring momentum to the polymers used as a dielectric in the EM Drives) something you agree with Ron?  Are you advocating that by stretching the dielectric polymer, this will enable the Quantum Vacuum to transfer momentum to the dielectric and serve as a means of EM Drive propulsion?
« Last Edit: 11/10/2014 04:44 pm by Rodal »

Offline Ron Stahl

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Re: EM Drive Developments
« Reply #3113 on: 11/10/2014 04:51 pm »
The discussion of anisotropy that you are referring to was motivated by Mulletron who has multiple posts advocating that the EM Drive measurements may be due to the Quantum Vacuum transferring momentum to the polymers used as a dielectric in the EM Drives.
That would be interesting if things without inertial mass could transfer momentum, but they can't; so obviously that notion is wrong.

Springwalker was not classified.  I have friends at DoD who speak about it.
« Last Edit: 11/10/2014 04:52 pm by Ron Stahl »

Offline Mulletron

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Re: EM Drive Developments
« Reply #3114 on: 11/10/2014 09:26 pm »
Decided to argue this time with the correct analogy, not neglecting we're dealing with a torsion pendulum:

Using similar methodology described starting at the 33 minute mark:


I decided to do some math problems to calculate the moment of inertia (Icm) of a rod 1 meter long with a mass of 1, 5.5, and 11 kg. (Range between 2.2 and ~24 pounds)
Moments of inertia:
1kg rod: I=.0833kg m2
5.5kg rod I=.4583kg m2
11kg rod I=.9166kg m2

From there I used those results to calculate a torsion pendulum oscillation period using the following constants: 1 meter length of suspension wire k=1Nm2
Oscillation periods:
1kg rod: 1.81 seconds
5.5kg rod: 4.25 seconds
11kg rod: 6 seconds

The point of this is to demonstrate that mass does make a dramatic difference in calculating moment of inertia and period of a torsion pendulum.



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Offline RotoSequence

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Re: EM Drive Developments
« Reply #3115 on: 11/10/2014 09:54 pm »
I think I'm with Mulletron on this one. We seem to have gotten into some sort of pissing match for no good reason, and I think a good point has been raised:
We don't actually know the test mass of the assembly, just the weight limit that the experimenters confined themselves to. As much as I can tell, with no background in the relevant fields, different weights will affect the dynamics of the assembly, and a dynamic analysis that uses 25 pounds as the mass cannot be assumed to be definitive. "Try" doesn't eliminate the possibility that the weight exceeded 25 pounds.
« Last Edit: 11/10/2014 09:58 pm by RotoSequence »

Offline Rodal

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Re: EM Drive Developments
« Reply #3116 on: 11/10/2014 10:24 pm »
I think I'm with Mulletron on this one. We seem to have gotten into some sort of pissing match for no good reason, and I think a good point has been raised:
We don't actually know the test mass of the assembly, just the weight limit that the experimenters confined themselves to. As much as I can tell, with no background in the relevant fields, different weights will affect the dynamics of the assembly, and a dynamic analysis that uses 25 pounds as the mass cannot be assumed to be definitive. "Try" doesn't eliminate the possibility that the weight exceeded 25 pounds.
1) The dynamic response of this structure (the EM Drive on the torsional pendulum) is governed by the ratio of the excitation frequency to the natural frequencies of the structure.  If one doesn't understand that the dynamic response is governed by the natural frequencies of the structure, one cannot hope to understand the dynamics of the response.

2) Mulletron stated that he didn't care about the natural frequency of the pendulum

3) Mulletron was under the completely wrong understanding that the pendulum at NASA Eagleworks was a hanging pendulum, which has a natural frequency completely independent of the suspended mass.  This is completely incorrect.  NASA Eagleworks used a torsional pendulum whose natural frequency goes like the square root of the suspended mass.

4) Once one understands 1) that the dynamic response is governed by the natural frequency and 2) that the natural frequency goes like the square root of the mass,  then it is simple to make some comparisons:

Suspended Mass         % difference of natural frequency to the one for 25 lb (absolute value)


45 lb                             34%
40 lb                             26%
35 lb                             18%
30 lb                             10%
25 lb                             0%
20lb                              11%
15 lb                             23%
10 lb                             40%
 5 lb                              55%

NOTE: what is unknown is the lumped mass (the EM Drive) at a given distance from the center of rotation.  Hence the rotational moment of inertia has to be computed with masses of different magnitude at a fixed distance from the center of rotation.  Therefore in this case (lumped mass on the torsional arm) the moment of inertia is proportional to the lumped mass.

As one can see from the above, if the mass is not 25 lb, it makes a small difference to the natural frequency, and therefore to the response, because the dynamic response goes like the square root of the mass

5) Moreover, we don't need to know the mass to compute the dynamic response at all.
 One can obtain, as we did, the natural frequency of the system by using a Fourier Transform.

So a dynamic analysis of the EM Drive is not dependent on the assumption of the mass.

We know the natural frequency of the system from:

A) Paul March
B) Fourier transform of the "Anomalous " report data (which agrees with the value given by Paul March)
C) Frobnicat readily obtained the natural frequency of the Eagleworks pendulum just by visually looking at the plots
D) @notSoSureOfIt readily realized that one could obtain both the natural frequency and the damping from the Eagleworks results.

« Last Edit: 11/10/2014 10:49 pm by Rodal »

Offline RotoSequence

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Re: EM Drive Developments
« Reply #3117 on: 11/10/2014 10:40 pm »
Looks like I stand corrected, then. Thinking back to galloping gerty, I probably should have realized, or, remembered, that vibration frequencies are largely independent of the load, until the frequency of the load matches the frequency of the structure, and then it starts amplifying itself.
« Last Edit: 11/10/2014 10:40 pm by RotoSequence »

Offline Mulletron

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Re: EM Drive Developments
« Reply #3118 on: 11/10/2014 10:45 pm »
Quote
Mulletron was under the completely wrong understanding that the pendulum at NASA Eagleworks was a hanging pendulum

I hit you back with a bad analogy the first time. I didn't misunderstand the thing was a torsion pendulum (in the title of the paper). You are acknowledging there is a huge difference over 25 pounds. So that makes the error bars like 50 percent.

Now isn't the pendulum at equilibrium before and shortly after each test pulse? Where is the frequency important? The slope of the leading and trailing edge of the test pulses are nearly exactly the same as the cal pulses. Both are well above the noise floor. The frequency is reported to be .222hz/4.5 seconds. You can see it in the noise in the graphs in the paper and after each overshoot. It doesn't sit there and vibrate at the natural frequency forever. Because it is damped.
http://personal.cityu.edu.hk/~bsapplec/natural.htm
http://en.wikipedia.org/wiki/Natural_frequency
http://www.chegg.com/homework-help/definitions/natural-frequency-5
« Last Edit: 11/11/2014 12:44 am by Mulletron »
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Offline frobnicat

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Re: EM Drive Developments
« Reply #3119 on: 11/10/2014 10:52 pm »
Yeah well, we already know the period of the harmonic oscillator better from the experimental graphs than from any calculations from parameters of the system like mass, length, stiffness (if experimenters cared to share).

My point was, I don't need to know the weight of a bell to know by hearing if it was hit by a hammer of hard material or by a hammer of soft material, especially when I have a recording of what it sounds like when hit by a hammer of steel and I know that the hammer of "mysterious material" imparts roughly the same recoil. I might not be able to tell apart tungsten from diamond, or rubber from soft wood, but I can tell apart hard from soft. Even if my audio sampling rate is in the same ballpark that the fundamental and in the same ball park as the time it takes for a rubber hammer to bounce, the ringing will make the difference (at equivalent recoil)

The thrust pulses sound rubber to me. It rings not like the hard rectangle pulse of the calibration pulse. This is a transient but this transient tells something important about the nature of the part that is not the gentle slope, this part that appears to be steep but is only so steep, that is not as steep as steel, so to speak. That part can't be "electromagnetic load time" because it is clearly above 1ms (otherwise it would appear hard) and anything electromagnetic goes the speed of light or near, so I don't see how you can discard my "20µs" three terms one liner as an all day long vacuous calculation : any effect that takes much more that 20µs, like for instance 100ms, to give full magnitude, is likely not a "real effect" (propellentless).

No hard ringing => no rise steeper than 100% full scale per 100ms
no rise steeper than 100% full scale per 100ms => no direct electromagnetic mediated force

Unless your theory would explain why the standing micro-waves fill the cavity at full magnitude in 20µs but would have to wait 100ms before reaching their plateau of momentum transfer to (or from) vacuum virtual particles. Seems very contrived to me. You can't handwave such a 100ms (or more) time constant away, like a suspect can't handwave away the fact that one of his hair was found on a crime scene as "hair splitting".

Hope this mention to prosecution will not entertain a certain level of paranoia : fact is, like for any rational investigation activity, hair splitting is also part of the job of science. And common sense is only in the eye of the beholder, but an eye is to use a microscope sometimes. I only say (with Rodal) : let's look at this difference of ringing with a microscope, let's split this hair and look if there is any thermal DNA in it. It will take some time (but not an indefinite amount of time) and we may find nothing convincing. But someone has to do it (the authors didn't, they just waved their hand in rectangle movements, that almost convinced me).

As an exit that would preserve the possibility of a real effect that has no such constraints of "non instantaneity" I propose the hypothesis that the microwave amplifier is the cause of the lack of punch of the signal, if the amplifier takes more than .1s to reach full power. That could be a natural explanation. Note I'm doing an effort here to find an hypothesis that would preserve the validity of the result in spite of the manifest difference relative to what would be expected from a clean rectangle force pulse (whatever it's source, Newtons imparted are not to remember what caused them). But, and it will be my last point, it appears there is less ringing (therefore less slope, therefore more time constant to reach plateau) at lower power levels (Brady c) than at higher power levels (Brady a and b). Granted, this is not that evident, I personally see a hint of that in the curves but would not say it is clear enough to make a definitive statement. It would be in disfavour of this "smooth power up" hypothesis as a source of the objective lack of punch of the transients.

You may disagree or find nonsense in a lot of things I just said. I find a lot of nonsense in what you said, this happens all the times in forums. Think we said what we had to say on the subject. Let us proceed. Wish you success with your personal line of research on the subject, can't help (for complete lack of knowledge in chirality and helicity and the such).

Now, will be time to scrap more data and reconstruct the signal with known procedures.
Found that thesis, a few of the introductory pages (15-17) are relevant.
Reconstructing force from harmonic motion
Equation 1.25 gives the Fourier transform of the Force signal from the inverse of the transfer function and the Fourier transform of the Displacement. Pretty simple and classic ! But later there are gory details like leakage of the discrete Fourier transform... mm, I'm afraid I get some Fourier leakage all over my shirt.

Oh, there is a nice citation in the thesis :

"An jeder Sache etwas zu sehen suchen, was noch niemand gesehen und
was noch niemand gedacht hat."

(To seek in everything something to see, which has never before been
seen nor sought.)

Georg Christoph Lichtenberg (1742-1799)
German mathematican and first professor
for experimental physics in Germany

« Last Edit: 11/10/2014 11:07 pm by frobnicat »

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