Quote from: Mulletron on 04/04/2015 02:01 amQuote from: mlindner on 04/04/2015 01:08 amIt appears my previous post got deleted.So I'll ask again. Has this psudoscience nonsense been found to be false yet? Have any proper scientists tested this contraption so that they can show that it doesn't work?I'm sure some "proper scientists" will come round for a look eventually. In the meantime, history has a lot to teach us about these sorts of things:http://amasci.com/weird/vindac.htmlhttp://www.lifehack.org/articles/lifestyle/6-world-changing-ideas-that-were-originally-rejected.htmlhttp://www.cracked.com/article_18822_5-famous-scientists-dismissed-as-morons-in-their-time.htmlEvery previous world changing idea didn't try to violate a founding principal of all physics, namely CoE and CoM.QuoteQuote...so that they can show that it doesn't workJust curious, what makes you so certain that it doesn't work? I mean, I have no idea if it works or not. The only certain thing I know here is that I don't know for certain if it works or doesn't.There is a growing body of evidence which suggest that it does work. It hasn't been proven by anybody that it doesn't work.I'm still waiting for an actual test of the operation of this craft. There haven't been any non-faulty experiments done yet that actually show it producing any thrust. Namely it must be tested in a vacuum. I don't try to merge philosophy and science and currently this "EM Drive" is purely in the realm of philosophy with no actual data yet. Thus I dismiss it just like the people claiming they made an anti-gravity drive in their garage.It's rather insulting that this forum topic even exists here.
Quote from: mlindner on 04/04/2015 01:08 amIt appears my previous post got deleted.So I'll ask again. Has this psudoscience nonsense been found to be false yet? Have any proper scientists tested this contraption so that they can show that it doesn't work?I'm sure some "proper scientists" will come round for a look eventually. In the meantime, history has a lot to teach us about these sorts of things:http://amasci.com/weird/vindac.htmlhttp://www.lifehack.org/articles/lifestyle/6-world-changing-ideas-that-were-originally-rejected.htmlhttp://www.cracked.com/article_18822_5-famous-scientists-dismissed-as-morons-in-their-time.html
It appears my previous post got deleted.So I'll ask again. Has this psudoscience nonsense been found to be false yet? Have any proper scientists tested this contraption so that they can show that it doesn't work?
Quote...so that they can show that it doesn't workJust curious, what makes you so certain that it doesn't work? I mean, I have no idea if it works or not. The only certain thing I know here is that I don't know for certain if it works or doesn't.There is a growing body of evidence which suggest that it does work. It hasn't been proven by anybody that it doesn't work.
...so that they can show that it doesn't work
Problem is no one is going to give that kind of money unless they are proved to work at the level they are now.
You accurately and completely answered the questions I asked. Unfortunately, I didn't ask my questions very well. http://forum.nasaspaceflight.com/index.php?topic=36313.msg1354235#msg1354235A constant-amplitude standing wave does indeed result in a zero time-average Poynting vector. However, I am questioning your conclusion that a constant-amplitude standing wave accurately represents a real resonator cavity such as the as-tested EM drive frustum. Instead, I would expect a decaying amplitude standing wave to be a more accurate model/plot (as would be derived from a full solution to Maxwell's equations with proper boundary conditions such as non-zero resistance, etc).Once a time-decaying standing wave is used for computation of a time-average Poynting vector, I'm having trouble seeing how the incident and reflected energy can perfectly cancel and become zero. I'll readily admit I may be oversimplifying and/or missing a fundamental concept; it's been a long time since I actually computed time constants for resonant cavities using Maxwell's equations and non-zero resistances.Phrased a bit differently, I believe only excited modes with current/thermal losses in the base plates will significantly weight the direction of the time-average Poynting vector. Each pair of incident/reflected waves would have a larger energy loss at the base plate with the excited E field (and therefore excited currents) than the energy loss at the opposing base plate. For modes with near-zero E fields at the base plate boundaries, each incident/reflected wave pair would have a near equal energy delta regardless of which base plate they came in contact with; the resulting time-averaged direction would be random and magnitude limited by the energy lost in the very first reflection (randomly either the large or small base, with a magnitude very close to zero).I view this Poynting vector discussion to be completely independent of whether Dr. White's QV interactions, or some other classical physics can explain the EM drive anomalous thrust. Just wanted to chime in on a what appeared to be the use of a constant-amplitude standing wave to describe a real-world system. Your earlier observation of a non-zero time averaged Poynting vector seemed like a reasonable statement given that only excited modes with current/thermal losses in the base plates would quickly diverge from the simplified constant-amplitude standing wave model. Regards,James
Quote from: Mulletron on 02/15/2015 07:48 amQuote from: Star-Drive on 02/15/2015 04:17 amFolks:In the meantime, lets ask why 60 watts of relatively harmonic free sine-wave RF power at the 1,937.118 MHz AKA the TM212 resonant frequency in this copper frustum cavity, can only generate a paltry ~60uN, whereas the Chinese claimed to have produce 160,000uN using just ~150 watts of 2,450 MHz RF signals from a magnetron? The magnetron RF signal source that is anything but a pure sine-wave generator, that instead has a modulated FM bandwidth of at least +/-30 MHz that is also concurrently amplitude modulated (AM) with thermal electron noise. Taking a critical look at this question, and knowing that the spectral shape of a magnetron looks like (see below) compared to a CW spike. It seems evident that a CW spike isn't the best waveform to use if you want to maximize thrust. Dollars to donuts says the Chinese are making full use of the available bandwidth of their resonant cavity by using that noisy magnetron. Magnetrons have lots of phase noise too. You can't easily use them on phased array radars because of that for example. ...I agree with Mulletron that the answer to Paul March's question is that it is much more effective to have a distributed power spectral density than the power concentrated at a single frequency spike. When the natural frequency changes in an unpredictable manner, it is much more effective to have a distributed power spectral density of excitation (it is the power spectral density ( http://en.wikipedia.org/wiki/Spectral_density#Power_spectral_density ) over the spectrum of changing natural frequencies that matters). ...This is evident from the very low Q's reported by NASA (7K to 22K) compared with the Chinese, who report a Q=117K : Quote from: Juan Yangthe resonant frequency and quality factor of the independent microwave resonator system are 2.44895 GHz and 117495.08 respectively...NASA's reported Q for the vacuum experiment is a meager Q = 6726, which is 17 times smaller than the Chinese reported Q = 117495.
Quote from: Star-Drive on 02/15/2015 04:17 amFolks:In the meantime, lets ask why 60 watts of relatively harmonic free sine-wave RF power at the 1,937.118 MHz AKA the TM212 resonant frequency in this copper frustum cavity, can only generate a paltry ~60uN, whereas the Chinese claimed to have produce 160,000uN using just ~150 watts of 2,450 MHz RF signals from a magnetron? The magnetron RF signal source that is anything but a pure sine-wave generator, that instead has a modulated FM bandwidth of at least +/-30 MHz that is also concurrently amplitude modulated (AM) with thermal electron noise. Taking a critical look at this question, and knowing that the spectral shape of a magnetron looks like (see below) compared to a CW spike. It seems evident that a CW spike isn't the best waveform to use if you want to maximize thrust. Dollars to donuts says the Chinese are making full use of the available bandwidth of their resonant cavity by using that noisy magnetron. Magnetrons have lots of phase noise too. You can't easily use them on phased array radars because of that for example. ...
Folks:In the meantime, lets ask why 60 watts of relatively harmonic free sine-wave RF power at the 1,937.118 MHz AKA the TM212 resonant frequency in this copper frustum cavity, can only generate a paltry ~60uN, whereas the Chinese claimed to have produce 160,000uN using just ~150 watts of 2,450 MHz RF signals from a magnetron? The magnetron RF signal source that is anything but a pure sine-wave generator, that instead has a modulated FM bandwidth of at least +/-30 MHz that is also concurrently amplitude modulated (AM) with thermal electron noise.
the resonant frequency and quality factor of the independent microwave resonator system are 2.44895 GHz and 117495.08 respectively
...A long time ago an RF engineer friend explained to me that cavities, filters and LC circuits are never dissipative. The power either goes through them or is reflected. If an RF signal with 20 MHz of bandwidth at 2085 MHz is sent through a 5 pole cavity filter with 5 MHz passband a large fraction of the RF power is simply reflected back to the amplifier.
Note here that we are choosing to work with themomentum density associated with the canonical energymomentum tensor rather than the Poynting vector; thelatter is expected to integrate to zero [9]
Further,they should be arranged so that the resulting tetrahe-dron (with the four particles placed at the vertices) hasno parity symmetry so that the vacuum photons get tosee a chiral structure. If these conditions are fulfilledthen a non-zero momentum develops which scales as thefourteenth inverse power of the length scale of the tetra-hedron.
Structure of polyethylene consists of directed tetrahedral configuration of sp3 hybridized carbon bonds along repeat structure with no free valence electrons.
From the letter linked to below:QuoteNote here that we are choosing to work with themomentum density associated with the canonical energymomentum tensor rather than the Poynting vector; thelatter is expected to integrate to zero [9]QuoteFurther,they should be arranged so that the resulting tetrahe-dron (with the four particles placed at the vertices) hasno parity symmetry so that the vacuum photons get tosee a chiral structure. If these conditions are fulfilledthen a non-zero momentum develops which scales as thefourteenth inverse power of the length scale of the tetra-hedron.http://arxiv.org/pdf/1011.4376.pdfhttp://iopscience.iop.org/0295-5075/93/4/41002/fulltext/epl_93_4_41002.htmlDon't think I've linked to this one before.QuoteStructure of polyethylene consists of directed tetrahedral configuration of sp3 hybridized carbon bonds along repeat structure with no free valence electrons.http://plastics.tamu.edu/class-resources/semi-conducting_polymers
It is shown that the first non-trivial contribution of the momentum transfer to the object from the radiation field occurs at fourth order in the Born series.
One should also note that for purely dielectric scatterers, the momentum is expected to vanish as the electromagnetic momentum density coincides with the Poynting vector.
So perhaps the only experimenters that have found something along these lines is NASA Eagleworks due to Paul March trying the PTFE and HDPE dielectric polymer inserts, and without them there is really no thrust (one of the very interesting things disclosed by Paul March is that Neoprene Rubber gave negligible thrust force). This would mean that the experimental forces measured by Shawyer and Juan Yang in China for EM Drives (using much higher power input) without thermoplastic inserts maybe just thermal effect artifacts.EDIT 2: It the authors are correct and one needs to take into account nonlinearity + anisotropy to get momentum from the quantum vacuum, this is much more complicated stuff than what Dr. White or Dr. Woodward have been considering. It will be much more difficult to prove or disprove ....There are non-uniqueness issues associated with an inverse nonlinear problem, and many other complications...There is no unique canonical correction to the energy-stress tensor, there are several and it is not clear which one is right for the problem....
Lastly, like any busy lab, Eagleworks could always use extra funding to deal with its daily heart burns and required salaries to keep it going. However we are currently a NASA sponsored facility, which sadly precludes being able to accept crowd sourcing or any other outside source of funding, unless it's through a commercial NASA Space Act Agreement that has to be approved up through NASA headquarters in Washington DC.
They can't accept dollars, but can they still accept donations of equipment? What about equipment "sold" to them for $1? Could provide some RF amplifiers for example.
Carl White, asked this interesting question:QuoteThey can't accept dollars, but can they still accept donations of equipment? What about equipment "sold" to them for $1? Could provide some RF amplifiers for example.So would it be possible to give you some contribution in kind? If so, what do you need?
Quote from: flux_capacitor on 04/05/2015 11:01 amCarl White, asked this interesting question:QuoteThey can't accept dollars, but can they still accept donations of equipment? What about equipment "sold" to them for $1? Could provide some RF amplifiers for example.So would it be possible to give you some contribution in kind? If so, what do you need?In general, government regs forbidding accepting gifts include "or value" precisely to avoid that loophole.¹ So equipment, whether donated or "sold" for $1, is still a donation of value. IIRC, even volunteering your own labour is forbidden unless specifically authorised.It's the same with NASA's unused facilities. NASA can't donate time to a private company, even if the facility (or staff!) would otherwise go unused, because they are required to charge "full equivalent commercial rates" or similar wording. The only exemption is if NASA and the private user "exchange services of equivalent value" via an SAA. NASA has been interpreting "equivalent value" as the private user letting NASA researchers play with their toys, which Congress has cracked down on recently.That said, an exemption for crowd-sourced donations makes sense. Similarly, a Patreon type system where amazing people sponsor their favourite research project via a small monthly amount. It may be something worth lobbying for. Even if it is just a pro-forma authorisation for agency officials to be able to use SAA's for specific crowd-sourcing efforts. Unfortunately, SAA's have been tightened even further by Congress.¹ For example, if I pay the tuition fees for the children of a government official to go to a private-school/top-university, or give them a free car/house/cheap-loan, etc, it's still bribery even though there was no cash-in-hand.
LENR
we have to continually tell management the value proposition for why they should fund our research, [...] once we get our hands around the physics they are using.
IMHO, only a very high power experiment producing a very high thrust (above a newton and more), and if possible even lift-off, where air flow circulation around the cavity could not account for the enormous thrust measured by equipment and observed with our own eyes, will settle the case. And will open the colonization of our solar system.