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.
http://forum.nasaspaceflight.com/index.php?topic=29276.msg1286223#msg1286223Nope.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.
http://ocw.mit.edu/high-school/physics/demonstrations-on-video/oscillations-gravitation/pendulum-periods/46:30 in.I'm not arguing anymore.
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-)
Quote from: Mulletron on 11/09/2014 07:25 amQuote from: aero on 11/08/2014 11:29 pmQuoteThe 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/cm052511wWell 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.htmAlso two exciting words: lamella twisting, here's helical chirality in PEhttp://www.esrf.eu/UsersAndScience/Publications/Highlights/2011/scm/scm4Chirality=proven truemechanical anisotropy=proven trueelectromagnetic 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.
Quote from: aero on 11/08/2014 11:29 pmQuoteThe 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/cm052511wWell 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.htmAlso two exciting words: lamella twisting, here's helical chirality in PEhttp://www.esrf.eu/UsersAndScience/Publications/Highlights/2011/scm/scm4Chirality=proven truemechanical anisotropy=proven trueelectromagnetic or magnetic anisotropy=not proven true, this is where spontaneous pt symmetry breaking comes in. Been working on this one for a while.
QuoteThe 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)
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.
Quote from: Rodal on 11/09/2014 11:50 amQuote from: Mulletron on 11/09/2014 07:25 amQuote from: aero on 11/08/2014 11:29 pmQuoteThe 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/cm052511wWell 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.htmAlso two exciting words: lamella twisting, here's helical chirality in PEhttp://www.esrf.eu/UsersAndScience/Publications/Highlights/2011/scm/scm4Chirality=proven truemechanical anisotropy=proven trueelectromagnetic 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.
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...
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).
Quote from: Rodal on 11/10/2014 04:15 pmStretching 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!
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.
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.
Mulletron was under the completely wrong understanding that the pendulum at NASA Eagleworks was a hanging pendulum