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#2840 by dustinthewind on 29 May, 2016 02:03
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Since there seems to be a mood toward theoretical speculations and musings lately, and before likely a flurry of experiments results, I'd like to share two links :
There have been discussion about "Feigel effect" (and sorry dr Rodal I can't tell how Feigel ideas relates to Bart van Tiggelen papers on similar topics). One of my favorite IMO no-nonsense top physicist blogger Lubos Motl has an interesting post about that (second post in the link, this is a short 2 posts thread) :
http://physics.stackexchange.com/questions/3186/poynting-vectors-and-feigel-effects
Of particular saliency what I put in bold in those excerpts "The controversies about the stress-energy tensor were inevitable. Only the total energy and momentum are conserved as a consequence of Noether's theorem, and how they're distributed in space may often be a matter of conventions." and "None of these things changes that the total energy and the total momentum are exactly conserved, because of the symmetries. Whether the momentum is being extracted from the vacuum is a matter of interpretation. You may also say that it is extracted from a low-frequency electromagnetic wave that was emitted by another object."
I'm too illiterate in QM and QFT to exploit this view of the difficulties in terms of dual interpretations, wonder if this is related to the point that looks not settled yet between interpreting Casimir effect as "vacuum fluctuations wavelength exclusion" or rather some kind of "relativistic retarded van der Waals force" ? The former is always put forward when presenting the effect but the second explains (experimentally proven ?) repulsive Casimir forces when other geometries are used (spheres...). So the former should be abandoned as false, but this is apparently not the case... could it be a matter of interpretation (with equivalent consequences) ?
Second link, other subject entirely, and probably more related to "Woodward's effect" thread (Machian physics...) but I'm sure people here (at least Notsosureofit) will find it intriguing if not aware of it yet :
http://www.epj.org/images/stories/news/2016/10.1140--epjp--i2016-16091-9.pdfQuote from: An interesting consequence of the general principle of relativity,
Øyvind Grøna and Torkild Jemterud, Eur. Phys. J. Plus (2016) 131: 91Abstract. We show that Einstein’s general theory of relativity, together with the assumption that the principle
of relativity encompasses rotational motion, predicts that in a flat Friedmann-Lemaitre-RobertsonWalker
(FLRW) universe model with dust and Lorentz Invariant Vacuum Energy (LIVE), the density
parameter of vacuum energy must have the value ΩΛ0 = 0.737. The physical mechanism connecting the
relativity of rotational motion with the energy density of dark energy is the inertial dragging effect. The
predicted value is necessary in order to have perfect inertial dragging, which is required for rotational
motion to be relative. If one accepts that due to the impossibility of defining motion for a single particle
in an otherwise empty universe, the universe must be constructed so that all types of motion are relative,
then this solves the so-called cosmological constant problem.
Mmm, I don't see how this explains away determination of an absolute 0 rotational frame by centrifugal forces in a Universe devoid of dark energy and such referential frame dragging... I need a no-nonsense physicist to tell me if it's as interesting as it sounds or just numerology.
I am pretty sure that rotation can be relative but relative to space time itself. If a black hole is rotating it drags space around with it. In order to not experience force from rotating one would have to rotate with the space. This should be like what Gravity probe B measured around the earth. That is if space time can drag on matter then rotating matter I think can some how drag on space time. I am just not sure what exactly that space time is or how the friction happens between them and if its connected with gravity itself.
On the other hand rotation with respect to a current loop is not relative. Either charge is rotating or it is not and the magnetic field depends on that.click this link to read why I suggest the magnetic field can't rotate if interested.
On the other hand I highly suspect that a magnetic field inside rotating space would rotate because space time it self is rotating. How that would play with magnetic fields on a cosmic scale I would be interested to learn about. -
#2841 by Monomorphic on 29 May, 2016 02:19
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Wow. After spectrum analysis, my magnetron is higher in frequency than rfmwguy's. I'm going to have to physically tune to 2.459Ghz, instead of 2.448Ghz
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#2842 by Eusa on 29 May, 2016 04:39
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In my humble understanding the quantum vacuum is mutable. There is the balance between the time development of the mass energy and of the vacuum quanta flow.
Maybe the neutrino radiation has something to do with that, I guess. Instead, the power of the vacuum energy transition must be immutable in respect of the mass, the constant flow for every elementary mass particle, just as in the Higgs mechanism. I see there is a direct connection between Higgs and the quantum vacuum. -
#2843 by FattyLumpkin on 29 May, 2016 04:41
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Monomorphic, do you not have a DC source for your Maggie? I know all the toys ($$$$) add up in the end but.....with such exacting (beautiful) sims! Let me know if I can pitch in some $ so's you can purchase some clean power. , Kevin PS: I do understand you can't tune with the DC source but, (attached) : ) , K
Eusa, (BTW), thanks for the input. I posted above before I saw your message. I'm going to relegate my time/energies to the many variables in frustum building and the test results, all the time while keeping theories in mind for the time being. FL aka Kevin
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#2844 by Gilbertdrive on 29 May, 2016 09:43
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I think Shawyer should be far, far more forthcoming because I believe he's keeping trade secrets.
There are alternatives between Shawyer's present flawed theory and the need for non-standard physics, as I've presented over the months I've striven here, though not often to you personally Gilbertdrive.
Theoretical strawmen can be setup, hacked and burned. Pinatas of Shawyer can be bashed. Emulation is said to be the sincerest form of flattery. Trees are known by their fruit, and wisdom of her children.
Shawyer can still keep trade secrets recognizing that he discovered a non standard physics phenomenum.
Since the fields in interplanetary space do not involve big power density, IMHO, the arguments about conservation of Energy And Momentum that were given earlier by Dr Rodal and Pr Frobnicat in these threads means that there is no possibility that the Emdrive gives much more thrust that a perfectly collimated photon rocket (excluding artifacts) with GR. But yes I was not involved at all in thread 1
Anyway, I think that we shall at least agree on the fact that it does not means that the measurements made by Shawyer are false. It does not means that the effect is not real.
After all, When there was the Galileo case, Galileo was almost as bad as Shawyer.
His notion of "turning aroung" was as ill defined as the Kinetic Energy of Shawyer, since the gravity was not discovered. In fact, his notion of turning around was an intuitive idea that if the equations are simpler in a referential, it is the right referential. Also, he wanted the trajectories to be circles around the sun, totally ignoring the ellipses that Kepler had demonstated, his calculus was giving less accurate results that old epicycles calculus (it was still usefull, because asking far less calculus than epicycles, at a time there were no computers)
He also made a modelisation of tides that involved the fact that there was only one tide a day. He became a laughingstock for that, since everybody in Venice could verify that there were 2 tides a day.
Despite all that, what he has discovered in his telescope was real. New stars, and Jupiter Satellites. Also his intuition of heliocentrism became an evidence when gravity was discovered.
I am personnaly open to Shawyer results. Even if I regret the fact that no reported test were run under vacuum, and battery powered, there are several arguments that are in his favour.Quote from: Star-Drive on 04/05/2015 05:34 AMQuoNext, using this new Q-V plasma simulation tool that utilizes the instantaneous E&M fields from COMSOL for one complete RF cycle in 5 degree increments as its input file, we are now seeing why we need the PTFE or HDPE dielectrics in the frustum while using near pure sine wave power levels below ~100W in the ~2.0 GHz frequency range to generate detectable thrust, and why Shawyer and the Chinese didn't while pumping 80W to 2,500W using magnetron RF sources. We think the reasons are two fold.
The first is that Shawyer and the Chinese both used magnetron RF sources for their experiments. An RF source that generates large AM, FM and PM modulation of the carrier wave with typical FM modulation bandwidth on the order of at least +/-20 MHz. (These time rate to change of energy modulations increase the Q-V density in our model.)
The second reason we found running these 3D Q-V plasma simulations for the EMPTY copper frustum, was that increasing the input power tends to focus the Q-V plasma flow from near omnidirectional from the frustum at low powers, to a much more jet like beam at higher powers measured in kW to tens of kW-rf. In fact the simulation for the 100W run predicted only ~50uN for our pure RF system with dielectric, while the 10kW run predicted a thrust level of ~6.0 Newton without a dielectric in the cavity. And at 100kW-rf it was now up to ~1300 Newton, but the input power to thrust production nonlinearity was starting to taper off around 50kW. Of course these Q-V plasma thrust predictions are based on the Q-V not being immutable and non-degradable, a feature we admit is not widely accepted by the mainstream physics community, at least at the moment.
It means that, unlike Shawyer inconsistent explanation, Shawyer results, by themselves, are consistent. They can be explained by new physics in a consistent way.
It is just sad that Shawyer gaves us these bad explanations. If he just has given his results as experimental results, without making false demonstration that it works with standard physics, it would have been better for everyone
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#2845 by SeeShells on 29 May, 2016 12:54
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Monomorphic, do you not have a DC source for your Maggie? I know all the toys ($$$$) add up in the end but.....with such exacting (beautiful) sims! Let me know if I can pitch in some $ so's you can purchase some clean power. , Kevin PS: I do understand you can't tune with the DC source but, (attached) : ) , K
Kevin,
Eusa, (BTW), thanks for the input. I posted above before I saw your message. I'm going to relegate my time/energies to the many variables in frustum building and the test results, all the time while keeping theories in mind for the time being. FL aka Kevin
He has a couple options to clean up the splatter spanning 20MHz.
He is running a standard Villard pulsed voltage doubler that outputs a 50% duty pulse and modify it with a fully rectifying voltage doubler circuit that outputs solid DC ~4KV.
https://en.wikipedia.org/wiki/Voltage_doubler
This would mean adding 2 HV rated Diodes and a couple of bleeder resistors and a couple HV caps to the power supply he is running. If he has another magnetron power supply he can rob it for the components he needs.
The thing he would need to do as well, is to not run the magnetron for extended times because he will go from a 50% pulsed duty cycle to a 100% and that will increase the heat in the magnetron.
To get around that duty cycle and to run for a longer time he could add a rheostat to control Vin.
Shell -
#2846 by Monomorphic on 29 May, 2016 14:23
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Keeping with my pledge to have an open emdrive project, attached is my first dataset from the live stream yesterday. I have someone doing analysis but you are welcome to make a chart or do one yourself. This is frustum pointed down on a torsion pendulum meaning not a thrust test but looking for artifacts such as lorentz or thermal forces when mag power turned on. Column are labeled. Mag power on is anything over 0 VDC. Temp was 82F.
Dave, I was watching live for a time until I had to go eat dinner - so I missed the last 10 minutes. It looked to me like you weren't seeing any lorentz or wire heating reaction. Why then did Yang report such high results from heating of the wire, but we are seeing nothing here? Maybe she ran the RF continuously rather than in steps.
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#2847 by Rodal on 29 May, 2016 15:10
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Keeping with my pledge to have an open emdrive project, attached is my first dataset from the live stream yesterday. I have someone doing analysis but you are welcome to make a chart or do one yourself. This is frustum pointed down on a torsion pendulum meaning not a thrust test but looking for artifacts such as lorentz or thermal forces when mag power turned on. Column are labeled. Mag power on is anything over 0 VDC. Temp was 82F.
Dave, I was watching live for a time until I had to go eat dinner - so I missed the last 10 minutes. It looked to me like you weren't seeing any lorentz or wire heating reaction. Why then did Yang report such high results from heating of the wire, but we are seeing nothing here? Maybe she ran the RF continuously rather than in steps.
Perhaps (?) because she felt she needed to provide a justification (for publication purposes) as to why the power cable made a difference, and running with batteries invalidated her previous thrust claims, and those are the reasons she could think about: Lorentz forces and thermal expansion due to heating of the cable. As usual with these discussions about Lorentz forces and thermal expansion I do not recall Yang providing a mathematical model with measurements supporting such an explanation. Rather, it looks like: hey the power cord made a difference (compared to using batteries) and these are the reasons I can think about why it would make a difference (not taking into account other reasons why the power cable makes a difference as the electromagnetic momentum and force carried by the cable, because that requires a more sophisticated analysis).
One should take into account that prior to Yang's latest measurements with batteries she had calculated a thrust force using a Finite Element Analysis based solely on Maxwell's equations, her calculations can be shown to be incorrect as she calculated the force solely from the stress tensor (*) and did not take into account the force due to the time derivative of the electromagnetic momentum in her calculations.
________________
(*) It can be shown that using any program based on Maxwell's equations (Meep, etc.) if one computes the force only from the stress tensor and ignores the contribution of the derivative of the electromagnetic momentum one is also going to obtain a spurious, nonsensical "thrust" proportional to the input power, which is purely due to not properly taking into account all terms in the equations of motion. -
#2848 by FattyLumpkin on 29 May, 2016 17:46
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Eusa, have you been in touch with Zellerium? His frustum is of concave-convex design and he has a science related degree (can't remember what in), but I'd think you might be able to discuss your theory(s) with him at length (time permitting). He is quite busy, but I think he still has the Emdrive bug for which I've oft chided him. LOL , Kevin
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#2849 by Monomorphic on 29 May, 2016 20:12
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Build Update: First video walk-around. Let me know what you think.
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#2850 by Rodal on 29 May, 2016 20:40
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Since there seems to be a mood toward theoretical speculations and musings lately, and before likely a flurry of experiments results, I'd like to share two links :
Lubos wrote that (http://physics.stackexchange.com/questions/3186/poynting-vectors-and-feigel-effects) in Jan 2011, four years before Croze's paper that Feigel's effect breaks the law of conservation of energy: http://arxiv.org/pdf/1304.3338v2.pdf
There have been discussion about "Feigel effect" (and sorry dr Rodal I can't tell how Feigel ideas relates to Bart van Tiggelen papers on similar topics). One of my favorite IMO no-nonsense top physicist blogger Lubos Motl has an interesting post about that (second post in the link, this is a short 2 posts thread) :
http://physics.stackexchange.com/questions/3186/poynting-vectors-and-feigel-effects
Of particular saliency what I put in bold in those excerpts "The controversies about the stress-energy tensor were inevitable. Only the total energy and momentum are conserved as a consequence of Noether's theorem, and how they're distributed in space may often be a matter of conventions." and "None of these things changes that the total energy and the total momentum are exactly conserved, because of the symmetries. Whether the momentum is being extracted from the vacuum is a matter of interpretation. You may also say that it is extracted from a low-frequency electromagnetic wave that was emitted by another object." ...
Do you know whether Lubos is aware of Croze's paper on the Feigel effect and whether Lubos has written anything further on this (in Lubos blog or elsewhere) during the last 5 years since he wrote that answer ?
Have other physicists seen a problem with Croze's paper ? (the supposed violation of conservation of energy predicated on a particular assumed definition for momentum, and on a particular definition of the stress-energy tensor, etc.).
Thanks (I ask because I do not follow Lubos's blog, but perhaps you do ?) -
#2851 by SeeShells on 29 May, 2016 20:44
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Build Update: First video walk-around. Let me know what you think.
Very clean setup! Nice work Monomorfic.
Shell -
#2852 by zellerium on 29 May, 2016 21:05
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Build Update: First video walk-around. Let me know what you think.
Wow that looks awesome!
Others have suggested that there will be lorentz forces if the leads are not twisted together.
Are you worried about thermal expansion of the magnetron leads?
Do you plan to run your tests long enough to reach thermal equilibirum?
If you're going with the latter, are you worried about heat detuning the cavity?
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#2853 by SeeShells on 29 May, 2016 21:57
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Took me a bit to dig this gem up even though I had it in my notes. I need to insert it because it is of vital importance...
elizabethgreene was a very sharp DYIer but became quiet for some reason. When we were talking about modifying the power supply in the microwaves she had a few great adds to the conversation.
I will add BE SAFE as Microwaves can and will do damage and the voltages can kill, if you don't know what you're doing ... don't.
http://forum.nasaspaceflight.com/index.php?topic=38203.msg1426364#msg1426364
« on: 09/15/2015 08:12 AM »
(snip)
What I learned this week:
Most replacement magnetrons have an advertised frequency center at 2460, not 2450.
A standard non-inverter microwave on 60hz power produces 4250v pulses at twice the line frequency, on for 8.3 ms, off for 8.3 ms.
With 2 caps and another diode you can replace the https://en.wikipedia.org/wiki/Voltage_doubler#Villard_circuit output stage with a https://en.wikipedia.org/wiki/Voltage_doubler#Greinacher_circuit . This provides continuous power output instead of pulsed.
You MUST cut the leads to the heater and supply power to them separately before running the magnetron grid on DC. The heater uses an RF choke to pull the HV down to 3-4 volts DC in a stock mangetron. Running 4.3kv through it will kill it and possibly you.
You can use oven diodes for this, but the oven caps aren't rated for the voltage. I found 10kv film capacitors on ebay for <$25. For safety add bleeder resistors to these caps.
Now I have a new question: How can I further change the output voltage and/or current limit this? That's this week's project.
Thanks in advance for the advice. -
#2854 by Monomorphic on 29 May, 2016 21:58
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Build Update: First video walk-around. Let me know what you think.
Wow that looks awesome!
Others have suggested that there will be lorentz forces if the leads are not twisted together.
Are you worried about thermal expansion of the magnetron leads?
Do you plan to run your tests long enough to reach thermal equilibirum?
If you're going with the latter, are you worried about heat detuning the cavity?
I am going to braid the leads (plus ground) together tomorrow. I have been meaning to do that.
I'm not so worried about thermal expansion in the leads. I'm more worried about melting the nylon connectors holding the HDPE insert in place! I will have IR videos as well to help characterize thermals.
I plan to run many tests. I'm not sure how long it would take to reach thermal equilibrium though. -
#2855 by zellerium on 29 May, 2016 22:24
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Build Update: First video walk-around. Let me know what you think.
Wow that looks awesome!
Others have suggested that there will be lorentz forces if the leads are not twisted together.
Are you worried about thermal expansion of the magnetron leads?
Do you plan to run your tests long enough to reach thermal equilibirum?
If you're going with the latter, are you worried about heat detuning the cavity?
I am going to braid the leads (plus ground) together tomorrow. I have been meaning to do that.
I'm not so worried about thermal expansion in the leads. I'm more worried about melting the nylon connectors holding the HDPE insert in place! I will have IR videos as well to help characterize thermals.
I plan to run many tests. I'm not sure how long it would take to reach thermal equilibrium though.
You have Nylon inside the frustum? That will probably turn out looking like our Nylon screws did within ~10 seconds:
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#2856 by Monomorphic on 29 May, 2016 22:39
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You have Nylon inside the frustum? That will probably turn out looking like our Nylon screws did within ~10 seconds:
Exactly. What material would be a good replacement? I'm opening up the emdrive tomorrow, so I can replace the nylon then. -
#2857 by zellerium on 29 May, 2016 22:55
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The planar amide (-CO-NH-) groups in Nylon are very polar, which I think means they oscillate similarly to water when subjected to microwaves.You have Nylon inside the frustum? That will probably turn out looking like our Nylon screws did within ~10 seconds:
Exactly. What material would be a good replacement? I'm opening up the emdrive tomorrow, so I can replace the nylon then.
We got around it by machining our tuning plate and HDPE with a slight taper so that it could be press fit.
We considered machining screws out of HDPE or Delrin because we had some, but decided the press fit would be the simplest method.
If you can't do that, maybe you could try adhesive or tape of some sort, but I don't know if either would hold up against the heat.
Maybe you could drill some interference holes on the back side of the HDPE use some metal screws from the backside?
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#2858 by ThinkerX on 29 May, 2016 23:00
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Took me a bit to dig this gem up even though I had it in my notes. I need to insert it because it is of vital importance...
elizabethgreene was a very sharp DYIer but became quiet for some reason. When we were talking about modifying the power supply in the microwaves she had a few great adds to the conversation.
I will add BE SAFE as Microwaves can and will do damage and the voltages can kill, if you don't know what you're doing ... don't.
Did Shell blow another magnetron?
http://forum.nasaspaceflight.com/index.php?topic=38203.msg1426364#msg1426364
« on: 09/15/2015 08:12 AM »
(snip)
What I learned this week:
Most replacement magnetrons have an advertised frequency center at 2460, not 2450.
A standard non-inverter microwave on 60hz power produces 4250v pulses at twice the line frequency, on for 8.3 ms, off for 8.3 ms.
With 2 caps and another diode you can replace the https://en.wikipedia.org/wiki/Voltage_doubler#Villard_circuit output stage with a https://en.wikipedia.org/wiki/Voltage_doubler#Greinacher_circuit . This provides continuous power output instead of pulsed.
You MUST cut the leads to the heater and supply power to them separately before running the magnetron grid on DC. The heater uses an RF choke to pull the HV down to 3-4 volts DC in a stock mangetron. Running 4.3kv through it will kill it and possibly you.
You can use oven diodes for this, but the oven caps aren't rated for the voltage. I found 10kv film capacitors on ebay for <$25. For safety add bleeder resistors to these caps.
Now I have a new question: How can I further change the output voltage and/or current limit this? That's this week's project.
Thanks in advance for the advice. -
#2859 by SeeShells on 30 May, 2016 00:25
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Took me a bit to dig this gem up even though I had it in my notes. I need to insert it because it is of vital importance...
elizabethgreene was a very sharp DYIer but became quiet for some reason. When we were talking about modifying the power supply in the microwaves she had a few great adds to the conversation.
I will add BE SAFE as Microwaves can and will do damage and the voltages can kill, if you don't know what you're doing ... don't.
Did Shell blow another magnetron?
http://forum.nasaspaceflight.com/index.php?topic=38203.msg1426364#msg1426364
« on: 09/15/2015 08:12 AM »
(snip)
What I learned this week:
Most replacement magnetrons have an advertised frequency center at 2460, not 2450.
A standard non-inverter microwave on 60hz power produces 4250v pulses at twice the line frequency, on for 8.3 ms, off for 8.3 ms.
With 2 caps and another diode you can replace the https://en.wikipedia.org/wiki/Voltage_doubler#Villard_circuit output stage with a https://en.wikipedia.org/wiki/Voltage_doubler#Greinacher_circuit . This provides continuous power output instead of pulsed.
You MUST cut the leads to the heater and supply power to them separately before running the magnetron grid on DC. The heater uses an RF choke to pull the HV down to 3-4 volts DC in a stock mangetron. Running 4.3kv through it will kill it and possibly you.
You can use oven diodes for this, but the oven caps aren't rated for the voltage. I found 10kv film capacitors on ebay for <$25. For safety add bleeder resistors to these caps.
Now I have a new question: How can I further change the output voltage and/or current limit this? That's this week's project.
Thanks in advance for the advice.
No I didn't blow another magnetron
and the reason it blew a couple months ago was a failure of the antenna probe in the frustum. The energy cascaded back down the coax in an increased VSWR which took out the magnetron.
Also, I was using a Panasonic inverter power supply. I was not using the type rfmwguy or Monomorphic are currently using. I was trying to provide info to either of them in case they were interested in modifying the power output to help clean it up the magnetron output. To rid it of the 20MHz mishmash of spectral splattering.
The frustum will resonate in a very narrow bandwidth of set frequencies and if the incoming frequencies are not within that band they will be reflected back in an increased VWSR and turned into heat.
and the reason it blew a couple months ago was a failure of the antenna probe in the frustum. The energy cascaded back down the coax in an increased VSWR which took out the magnetron.