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#620 by Monomorphic on 18 Jul, 2017 17:26
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First layer adhesion successful. That is usually a good sign. Now so long as the power doesn't go out I should be fine. I will pick up a beefy uninterruptible power supply (UPS) tomorrow. This printer draws 70W.
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#621 by SeeShells on 18 Jul, 2017 18:36
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First layer adhesion successful. That is usually a good sign. Now so long as the power doesn't go out I should be fine. I will pick up a beefy uninterruptible power supply (UPS) tomorrow. This printer draws 70W.
Wish I had a "love" button on here instead of a "like". Very sweet monomorphic!
Shell -
#622 by Bob012345 on 18 Jul, 2017 20:15
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2nd paper about the EmDrive and McCulloch's MiHsC just published in EPL and freely available:
• McCulloch, M. E. (July 2017). "Testing quantised inertia on emdrives with dielectrics" (PDF). EPL. 118 (3). doi:10.1209/0295-5075/118/34003.
In this second EPL paper, the speed of light does not vary anymore within the cavity. Instead, more Unruh waves fit the wide end of the cavity than its narrow end, continuously shifting the center of inertial mass of the microwaves towards the wide end: the cavity then has to move towards the small end, for momentum to be conserved. As the speed of light does not change in the latter model, there is no more relativistic violation, which was the main criticism of the 1st paper.
I read the paper a couple of weeks ago. His equations apparently conserve momentum between the frustum and the EM momentum inside, but it still remains unclear how momentum escapes from inside the cavity to propel the frustum. He relies on his theory and the assumption that the difference in the Unruh spectrum between the two ends is enough to result in thrust. IMO, the real mechanism is the power being lost "inefficiently" to heating the copper and the air, where the exchange of momentum between the photons and the random moving atoms is non-conservative.
Todd
I can't think of any situation where such interactions could be non-conservative. I believe momentum is conserved on a photon by photon basis from photon generation to photon destruction and every interaction in between. As an aside, notice that the paper suggests the average index of refraction in the cavity plays a direct role. -
#623 by WarpTech on 18 Jul, 2017 21:06
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2nd paper about the EmDrive and McCulloch's MiHsC just published in EPL and freely available:
• McCulloch, M. E. (July 2017). "Testing quantised inertia on emdrives with dielectrics" (PDF). EPL. 118 (3). doi:10.1209/0295-5075/118/34003.
In this second EPL paper, the speed of light does not vary anymore within the cavity. Instead, more Unruh waves fit the wide end of the cavity than its narrow end, continuously shifting the center of inertial mass of the microwaves towards the wide end: the cavity then has to move towards the small end, for momentum to be conserved. As the speed of light does not change in the latter model, there is no more relativistic violation, which was the main criticism of the 1st paper.
I read the paper a couple of weeks ago. His equations apparently conserve momentum between the frustum and the EM momentum inside, but it still remains unclear how momentum escapes from inside the cavity to propel the frustum. He relies on his theory and the assumption that the difference in the Unruh spectrum between the two ends is enough to result in thrust. IMO, the real mechanism is the power being lost "inefficiently" to heating the copper and the air, where the exchange of momentum between the photons and the random moving atoms is non-conservative.
Todd
I can't think of any situation where such interactions could be non-conservative. I believe momentum is conserved on a photon by photon basis from photon generation to photon destruction and every interaction in between. As an aside, notice that the paper suggests the average index of refraction in the cavity plays a direct role.
Dissipative forces like Friction, are non-conservative. The energy lost to heat is random, it cannot also be used for the kinetic energy put into thrust. As long as heat is being generated, some of the energy is not going into acceleration of the frustum. Your notion of "on a photon by photon basis" is an ideal situation, which assumes perfect conductors and no air to absorb momentum and recoils. It's not realistic.
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#624 by SteveD on 18 Jul, 2017 22:15
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Monomorphic, am I correct that the test article you are building has 3D printed endplates with sidewalls of some form of cardboard all covered with conductive tape? Seems like an affordable build, though I am reminded of some of the construction materials used for early aircraft.
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#625 by Monomorphic on 18 Jul, 2017 22:32
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Monomorphic, am I correct that the test article you are building has 3D printed endplates with sidewalls of some form of cardboard all covered with conductive tape? Seems like an affordable build, though I am reminded of some of the construction materials used for early aircraft.
The sidewalls are constructed of clear plastic sheet, not cardboard. Cardboard was too wrinkly when formed into the necessary curve. The plastic formed a nice smooth surface to adhere the EMI copper shielding adhesive foil to. I picked up the plastic sheet at the local arts and crafts store. It is used by college art students for some kind of printing process.
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#626 by Bob012345 on 19 Jul, 2017 00:26
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2nd paper about the EmDrive and McCulloch's MiHsC just published in EPL and freely available:
• McCulloch, M. E. (July 2017). "Testing quantised inertia on emdrives with dielectrics" (PDF). EPL. 118 (3). doi:10.1209/0295-5075/118/34003.
In this second EPL paper, the speed of light does not vary anymore within the cavity. Instead, more Unruh waves fit the wide end of the cavity than its narrow end, continuously shifting the center of inertial mass of the microwaves towards the wide end: the cavity then has to move towards the small end, for momentum to be conserved. As the speed of light does not change in the latter model, there is no more relativistic violation, which was the main criticism of the 1st paper.
I read the paper a couple of weeks ago. His equations apparently conserve momentum between the frustum and the EM momentum inside, but it still remains unclear how momentum escapes from inside the cavity to propel the frustum. He relies on his theory and the assumption that the difference in the Unruh spectrum between the two ends is enough to result in thrust. IMO, the real mechanism is the power being lost "inefficiently" to heating the copper and the air, where the exchange of momentum between the photons and the random moving atoms is non-conservative.
Todd
I can't think of any situation where such interactions could be non-conservative. I believe momentum is conserved on a photon by photon basis from photon generation to photon destruction and every interaction in between. As an aside, notice that the paper suggests the average index of refraction in the cavity plays a direct role.
Dissipative forces like Friction, are non-conservative. The energy lost to heat is random, it cannot also be used for the kinetic energy put into thrust. As long as heat is being generated, some of the energy is not going into acceleration of the frustum. Your notion of "on a photon by photon basis" is an ideal situation, which assumes perfect conductors and no air to absorb momentum and recoils. It's not realistic.
You brought non-conservative up in the context of generating thrust. Momentum is always conserved even with non-conservative forces. Yes, forces can be non-conservative and dissipative like, friction but that's never going to lead to a net thrust. You were talking about this dissipative forces leading to a net thrust. I don't see a thrust generating mechanism here. -
#627 by John Gallagher on 19 Jul, 2017 00:56
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New breakthrough discovery-every quantum particle travels backwards. physics.org, 7-18
What is this about?
?
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#628 by WarpTech on 19 Jul, 2017 01:48
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2nd paper about the EmDrive and McCulloch's MiHsC just published in EPL and freely available:
• McCulloch, M. E. (July 2017). "Testing quantised inertia on emdrives with dielectrics" (PDF). EPL. 118 (3). doi:10.1209/0295-5075/118/34003.
In this second EPL paper, the speed of light does not vary anymore within the cavity. Instead, more Unruh waves fit the wide end of the cavity than its narrow end, continuously shifting the center of inertial mass of the microwaves towards the wide end: the cavity then has to move towards the small end, for momentum to be conserved. As the speed of light does not change in the latter model, there is no more relativistic violation, which was the main criticism of the 1st paper.
I read the paper a couple of weeks ago. His equations apparently conserve momentum between the frustum and the EM momentum inside, but it still remains unclear how momentum escapes from inside the cavity to propel the frustum. He relies on his theory and the assumption that the difference in the Unruh spectrum between the two ends is enough to result in thrust. IMO, the real mechanism is the power being lost "inefficiently" to heating the copper and the air, where the exchange of momentum between the photons and the random moving atoms is non-conservative.
Todd
I can't think of any situation where such interactions could be non-conservative. I believe momentum is conserved on a photon by photon basis from photon generation to photon destruction and every interaction in between. As an aside, notice that the paper suggests the average index of refraction in the cavity plays a direct role.
Dissipative forces like Friction, are non-conservative. The energy lost to heat is random, it cannot also be used for the kinetic energy put into thrust. As long as heat is being generated, some of the energy is not going into acceleration of the frustum. Your notion of "on a photon by photon basis" is an ideal situation, which assumes perfect conductors and no air to absorb momentum and recoils. It's not realistic.
You brought non-conservative up in the context of generating thrust. Momentum is always conserved even with non-conservative forces. Yes, forces can be non-conservative and dissipative like, friction but that's never going to lead to a net thrust. You were talking about this dissipative forces leading to a net thrust. I don't see a thrust generating mechanism here.
The "Q" of the system depends on the power dissipation (losses). If the EmDrive works without radiating momentum, it is because the power dissipation is asymmetrical. I can't think of any other way it could work, if it works.
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#629 by mwvp on 19 Jul, 2017 02:43
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Yes, forces can be non-conservative and dissipative like, friction but that's never going to lead to a net thrust. You were talking about this dissipative forces leading to a net thrust. I don't see a thrust generating mechanism here.
If you were on a cart with a large swinging pendulum swinging forward and back in the direction of the carts travel, and you dragged your feet off the cart on the road every time the pendulum swung forward (friction), you would ratchet forward. You would be selectively dissipating momentum as heat.
You can do this trick with a dispersive laser cavity. Depending on the sideband you selectively tune, you can enhance or dampen vibrations with radiation pressure.
I assert the frustrum does just this; the frustrum is both the accelerating mass accelerated by radiation pressure and the resonant cavity.
from http://arxiv.org/abs/1303.0733 pg 20 -
#630 by LowerAtmosphere on 19 Jul, 2017 11:40
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https://www.york.ac.uk/news-and-events/news/2017/research/quantum-particle-backwards/
"However, this is no longer true on microscopic scales - quantum particles can partially go into reverse and travel in the direction opposite to their momentum. This unique property is known as ‘backflow’."
“We have shown that backflow can always occur, even if a force is acting on the quantum particle while it travels. The backflow effect is the result of wave-particle duality and the probabilistic nature of quantum mechanics, and it is already well understood in an idealised case of force-free motion.”
More news from NASA:
https://www.nextbigfuture.com/2017/07/nasa-technologist-proposes-acceleration-mechanics-for-new-propellant-less-space-drives.html
"By applying entanglement to the thin-shell mechanism, one can allow the thin-shell to be the observer between an object’s density and its surrounding environment density in order to conserve both entanglement and energy between the two densities. Whereby, changes to these densities invoke changes to the thin-shell thickness about an object, which when non-uniform across the object, accelerates the object in order to conserve energy and momentum between the thin-shell and the two densities."
Edit: Note that the chameleon theory was presented earlier. -
#631 by JohnFornaro on 19 Jul, 2017 12:28
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First layer adhesion successful. That is usually a good sign. Now so long as the power doesn't go out I should be fine. I will pick up a beefy uninterruptible power supply (UPS) tomorrow. This printer draws 70W.
Nice to see a desktop 3D printer.
Will it do steel? How much did it cost?
Maybe a website for the manufacturer?
Thanx! -
#632 by JohnFornaro on 19 Jul, 2017 12:30
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Yes, forces can be non-conservative and dissipative like, friction but that's never going to lead to a net thrust. You were talking about this dissipative forces leading to a net thrust. I don't see a thrust generating mechanism here.
If you were on a cart with a large swinging pendulum swinging forward and back in the direction of the carts travel, and you dragged your feet off the cart on the road every time the pendulum swung forward (friction), you would ratchet forward. You would be selectively dissipating momentum as heat.
I'm better at analogies than math, and see them as aids in my 'disability'.
In space, what is the "road" that you drag your feet off of with such rhythm?
Isn't that the crux of the CoM objection?
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#633 by Bob Woods on 19 Jul, 2017 15:45
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FYI: http://news.stanford.edu/2017/07/15/maryam-mirzakhani-stanford-mathematician-and-fields-medal-winner-dies/
"Mastering these approaches allowed Mirzakhani to pursue her fascination for describing the geometric and dynamic complexities of curved surfaces – spheres, doughnut shapes and even amoebas – in as great detail as possible. Her work was highly theoretical in nature, but it could have impacts concerning the theoretical physics of how the universe came to exist and, because it could inform quantum field theory, secondary applications to engineering and material science. Within mathematics, it has implications for the study of prime numbers and scamgraphy."[/size] -
#634 by Bob012345 on 19 Jul, 2017 17:30
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Yes, forces can be non-conservative and dissipative like, friction but that's never going to lead to a net thrust. You were talking about this dissipative forces leading to a net thrust. I don't see a thrust generating mechanism here.
If you were on a cart with a large swinging pendulum swinging forward and back in the direction of the carts travel, and you dragged your feet off the cart on the road every time the pendulum swung forward (friction), you would ratchet forward. You would be selectively dissipating momentum as heat.
You can do this trick with a dispersive laser cavity. Depending on the sideband you selectively tune, you can enhance or dampen vibrations with radiation pressure.
I assert the frustrum does just this; the frustrum is both the accelerating mass accelerated by radiation pressure and the resonant cavity.
from http://arxiv.org/abs/1303.0733 pg 20
I think in order for that to work one has to fundamentally change the properties of something, for example, photons in flight, without undoing the effect one is trying to accomplish, the net thrust. Prof. Woodward's Mach Effect thrusters do that by changing the mass and McCulloch's theory of the EMDrive does that with Unruh radiation and quantized inertia.
How does this idea propose to do that? -
#635 by mwvp on 19 Jul, 2017 19:15
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Yes, forces can be non-conservative and dissipative like, friction but that's never going to lead to a net thrust. You were talking about this dissipative forces leading to a net thrust. I don't see a thrust generating mechanism here.
If you were on a cart with a large swinging pendulum swinging forward and back in the direction of the carts travel, and you dragged your feet off the cart on the road every time the pendulum swung forward (friction), you would ratchet forward. You would be selectively dissipating momentum as heat.
I'm better at analogies than math, and see them as aids in my 'disability'.
In space, what is the "road" that you drag your feet off of with such rhythm?
Isn't that the crux of the CoM objection?
Excellent point; I think of it as the "boot-strap" objection - you can't pull yourself up by your boot-straps or move a car when inside pushing on the steering wheel, et.
I can't think of a non-technical metaphor for Lorentz Invariance. All I can say is study the Sagnac Effect, checkout BAE's photonic laser thruster.
Because unlike in materials in which the speed of wave propagation in materials in different inertial frames differs, in the vacuum the speed of light is an absolute and the same for all inertial frames. Special relativity isn't generally disputed.
Consequently, momentum is conserved via the Doppler Effect.
Again, Macken in his book free book "Only Spacetime" in and at the end of chapter 1 appendix explains a lot by comparing particles to energy in resonant cavities, and analyzing the dynamics. http://onlyspacetime.com/
It may help to stop seeing particles as objects in the "void" of a vacuum, and instead think of the vacuum as a solid that allows the propagation of dark soliton/oscillon-like "holes".
Energy, propagating (far-field) as photons or microwaves in a resonant cavity apply momentum and oppose change of the metallic can they propagate in. If you wave a can of light around, the light in the can will slosh around by and according to the Doppler Effect, implicit in Lorentz invariance and special relativity. You do not move the vacuum photons propagate in when you shake a can. If it were a chunk of glass with sound waves, or sound in air, then as you shake the cavity the sound is dragged along with the medium its propagating in.
In light is propagating in a refractive material, then you will drag the light around, according to the Fresnel Drag equation. The higher the permiability or permittivity, the less Sagnac effect Doppler shift. -
#636 by mwvp on 19 Jul, 2017 19:20
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Yes, forces can be non-conservative and dissipative like, friction but that's never going to lead to a net thrust. You were talking about this dissipative forces leading to a net thrust. I don't see a thrust generating mechanism here.
If you were on a cart with a large swinging pendulum swinging forward and back in the direction of the carts travel, and you dragged your feet off the cart on the road every time the pendulum swung forward (friction), you would ratchet forward. You would be selectively dissipating momentum as heat.
You can do this trick with a dispersive laser cavity. Depending on the sideband you selectively tune, you can enhance or dampen vibrations with radiation pressure.
I assert the frustrum does just this; the frustrum is both the accelerating mass accelerated by radiation pressure and the resonant cavity.
from http://arxiv.org/abs/1303.0733 pg 20
I think in order for that to work one has to fundamentally change the properties of something, for example, photons in flight, without undoing the effect one is trying to accomplish, the net thrust. Prof. Woodward's Mach Effect thrusters do that by changing the mass and McCulloch's theory of the EMDrive does that with Unruh radiation and quantized inertia.
How does this idea propose to do that?
When you accelerate the cavity, the dispersion (refractive index gradient or group-velocity gradient) Doppler shifts the photons. Either the can has less apparent inertia/mass as you accelerate base to apex, or more apparent mass if the acceleration is apex to base. Base to apex field amplitude decreases. Apex to base field amplitude increases (motor/generator).
Again, see the end of chapter 1 in Macken for the math. Or BAE's photonic thruster discussion of Doppler Shift and conservation of momentum. -
#637 by Bob012345 on 19 Jul, 2017 19:21
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The "Q" of the system depends on the power dissipation (losses). If the EmDrive works without radiating momentum, it is because the power dissipation is asymmetrical. I can't think of any other way it could work, if it works.
Since you brought up the Q factor here I want to quote a question I had almost a year ago that I never got an answer to;QuoteA question I would like some thought to. Please don't get mad if this seems stupid.
These devices seem critically dependent on high Q to enhance and multiply the force differential which is extremely difficult to achieve since destructive interference has infinite possibilities to happen. I wonder if there is fundamentally a different way to get to the same end yet without needing to sustain resonance. What I'm thinking of is an asymmetrically designed device that acts more as a waveguide to recirculate the radiation as opposed to bounce it back and forth interacting with the ends. This mode of operation would be similar to photon recycling schemes recently validated by experiment.
BTW, concerning resonance, in recent photon recycling experiments by Y. Bae, an effective resonance was set up between mirrors so stable, the author could move the mirror around with his hand and maintain the resonance. He used a so-called gain medium in the loop. Do you builders have an analogy with microwaves? Thanks.
The first part which reflects my earlier naive understanding of EmDrive forces, still I'm thinking of waveguides that allow the waves to propagate one way along the outer surface and come back in the center, along an inner surface. I was thinking that multiple looping of the waves in the waveguide and impinging on the end plates would be a poor mans substitute for cavity resonance. In the second part, which could apply to the usual cavity designs, I'm wondering if a gain medium for microwaves exists that would stabilize the resonance as it does in Bae's experiments. He can move a mirror with his hand around and maintain resonance! Or even more heretical, could there be an optical version of the EMDrive cavity that took advantage of the same principle on which the EMDrive works, if it works, but was easier and safer to operate? Such a device might be visualized as a flat plate with a multitude of LED lasers and micro cavities or perhaps still one larger device with stabilized resonance. Bae achieved around a half megawatt intracavity power in his small tabletop demo from a 500 W laser. Please be patient with this question. Thanks. -
#638 by Bob012345 on 19 Jul, 2017 19:52
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Yes, forces can be non-conservative and dissipative like, friction but that's never going to lead to a net thrust. You were talking about this dissipative forces leading to a net thrust. I don't see a thrust generating mechanism here.
If you were on a cart with a large swinging pendulum swinging forward and back in the direction of the carts travel, and you dragged your feet off the cart on the road every time the pendulum swung forward (friction), you would ratchet forward. You would be selectively dissipating momentum as heat.
You can do this trick with a dispersive laser cavity. Depending on the sideband you selectively tune, you can enhance or dampen vibrations with radiation pressure.
I assert the frustrum does just this; the frustrum is both the accelerating mass accelerated by radiation pressure and the resonant cavity.
from http://arxiv.org/abs/1303.0733 pg 20
I think in order for that to work one has to fundamentally change the properties of something, for example, photons in flight, without undoing the effect one is trying to accomplish, the net thrust. Prof. Woodward's Mach Effect thrusters do that by changing the mass and McCulloch's theory of the EMDrive does that with Unruh radiation and quantized inertia.
How does this idea propose to do that?
When you accelerate the cavity, the dispersion (refractive index gradient or group-velocity gradient) Doppler shifts the photons. Either the can has less apparent inertia/mass as you accelerate base to apex, or more apparent mass if the acceleration is apex to base. Base to apex field amplitude decreases. Apex to base field amplitude increases (motor/generator).
Again, see the end of chapter 1 in Macken for the math. Or BAE's photonic thruster discussion of Doppler Shift and conservation of momentum.
Thanks for the explanation and free book reference!
Reminds me of the Doppler shift for relativistic photon rockets. For beam powered photon rockets, the more relativistic the ship the higher percentage of beam energy gets converted to ship kinetic energy and it approaches 100% as v approaches c. I wondered if one could fool Mother Nature by coupling EM radiation in one direction to relativistic electrons in or on the cavity preferentially over the reverse direction and thus convert more energy into kinetic energy going one way. I though this might break the conversion limit. Probably not but it's fun to think about. -
#639 by JasonAW3 on 19 Jul, 2017 20:08
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This may have already been answered long ago, but; Has anyone considered that the EM drive is somehow tapping into the Earth's magnetic lines of force?
While the overall field seems quite low, the overall magnetic flow could be a factor.
Like I said, it likely was covered, but I'd like to put that out there in case it wasn't...
?