Wouldn't thermoelastic waves from the small end also cause vibrations that would propagate throughout the device? The copper cone is not going to isolate the two ends. The interaction of vibrations from both ends should produce an interesting pattern.
Quote from: Notsosureofit on 11/01/2014 02:01 pmQuote from: Rodal on 11/01/2014 01:57 pmThe coupling coefficient is non-trivial. But calculating the Fourier non-dimensional time is trivial, so let's calculate the time for which the Fourier non-dimensional = 1, which is simply ((thickness)^2)/thermalDiffusivitythermalDiffusivity = 1.11*10^(-4) m/sso for thickness of copper = 1/8 in = 0.00318 mhence time = 0.0908 sso for thickness of copper = 1/16 in = 0.00159 mhence time = 0.0227 sso for thickness of copper = 0.022 in = 0.000559 mhence time = 0.0028 sSo, the initial thermal effect on the copper thickness is clearly impulsive, from the point of view of the much slower response of the inverted torsional pendulum (with period ~ 4.5 s)Great! Look at the drumhead expansion of the big end .002" copper FRP w/ resistve heating from the Cu loss!http://en.wikipedia.org/wiki/FR-4I need to know the boundary conditions for the 0.002" copper.Is the 0.002" copper a separate thin sheet of copper, or is the 0.002" copper thermally sprayed on the fiber-reinforced-polymer substrate and hence integrally bonded to it, or is the 0.002" copper adhered to the fiber-reinforced-polymer substrate ? Can the 0.002" be easily peeled apart from the polymer composite substrate?(Can one hold on to that 0.002" copper with pliers and peel it apart from the polymer composite substrate?
Quote from: Rodal on 11/01/2014 01:57 pmThe coupling coefficient is non-trivial. But calculating the Fourier non-dimensional time is trivial, so let's calculate the time for which the Fourier non-dimensional = 1, which is simply ((thickness)^2)/thermalDiffusivitythermalDiffusivity = 1.11*10^(-4) m/sso for thickness of copper = 1/8 in = 0.00318 mhence time = 0.0908 sso for thickness of copper = 1/16 in = 0.00159 mhence time = 0.0227 sso for thickness of copper = 0.022 in = 0.000559 mhence time = 0.0028 sSo, the initial thermal effect on the copper thickness is clearly impulsive, from the point of view of the much slower response of the inverted torsional pendulum (with period ~ 4.5 s)Great! Look at the drumhead expansion of the big end .002" copper FRP w/ resistve heating from the Cu loss!http://en.wikipedia.org/wiki/FR-4
The coupling coefficient is non-trivial. But calculating the Fourier non-dimensional time is trivial, so let's calculate the time for which the Fourier non-dimensional = 1, which is simply ((thickness)^2)/thermalDiffusivitythermalDiffusivity = 1.11*10^(-4) m/sso for thickness of copper = 1/8 in = 0.00318 mhence time = 0.0908 sso for thickness of copper = 1/16 in = 0.00159 mhence time = 0.0227 sso for thickness of copper = 0.022 in = 0.000559 mhence time = 0.0028 sSo, the initial thermal effect on the copper thickness is clearly impulsive, from the point of view of the much slower response of the inverted torsional pendulum (with period ~ 4.5 s)
Am I to conclude from the last few posts the thrust produced by the Eagleworks EM drive is in fact a thermoelestic artefact?
Quote from: ThinkerX on 11/02/2014 04:14 amAm I to conclude from the last few posts the thrust produced by the Eagleworks EM drive is in fact a thermoelestic artefact?We cannot say that. We can say that Rodal's hypothesis is that the Eagleworks EM drive is a thermoelectric artifact, that there is a distinct possibility that it is a thermoelectric artifact, and that Rodal in the process of demonstrating the likelihood of that cause with his analysis.
A [Date Acquired: Oct 30, 2014] paper co-authored by Dr. White presented at the Institution of Electrical and Electronic Engineers: http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20140013174.pdf where he discusses short trips to the Jovian and Saturnian moons and "uncovers an energy paradox" (see Appendix A) .Quote from: White et alIt is not the intent here to detail the theory or engineering of quantum vacuum plasma thrusters (Q-Thrusters). Rather, an overview of the foundational physics and laboratory findings are given.Q-Thrusters attempt to use the properties of the “quantum vacuum” to propel a spacecraft. Quantum Electrodynamics (QED) predicts that the quantum vacuum (the lowest state of the electromagnetic field) is not empty, but rather a sea of virtual particles and photons that pop into and out of existence stemming from the Heisenberg uncertainty principle.A number of approaches to utilize this quantum vacuum to transfer momentum from a spacecraft to the vacuum have been synopsized in [1].A Q-Thruster uses the same principles as conventional plasma thrusters, namely magnetohydrodynamics, where plasma is exposed to crossed electric and magnetic fields which induce a drift of the entire plasma in a direction orthogonal to the applied fields. The difference arises in that a Q-Thruster uses quantum vacuum fluctuations as the “propellant” source, eliminating the need for conventional on-board propellant. A discussion of spacecraft “conservation of energy” is given in Appendix A. Recent laboratory test results [2] indicate the expected thrust-to-power ratio for flight applications could be in the 0.4 – 4.0 N/kWe range, which is one to two orders of magnitude greater than current operational electric thrusters. This combination of characteristics – relatively high specific thrust combined with essentially zero on-board propellant requirement - suggest space mission performance levels significantly exceeding current capabilities.
It is not the intent here to detail the theory or engineering of quantum vacuum plasma thrusters (Q-Thrusters). Rather, an overview of the foundational physics and laboratory findings are given.Q-Thrusters attempt to use the properties of the “quantum vacuum” to propel a spacecraft. Quantum Electrodynamics (QED) predicts that the quantum vacuum (the lowest state of the electromagnetic field) is not empty, but rather a sea of virtual particles and photons that pop into and out of existence stemming from the Heisenberg uncertainty principle.A number of approaches to utilize this quantum vacuum to transfer momentum from a spacecraft to the vacuum have been synopsized in [1].A Q-Thruster uses the same principles as conventional plasma thrusters, namely magnetohydrodynamics, where plasma is exposed to crossed electric and magnetic fields which induce a drift of the entire plasma in a direction orthogonal to the applied fields. The difference arises in that a Q-Thruster uses quantum vacuum fluctuations as the “propellant” source, eliminating the need for conventional on-board propellant. A discussion of spacecraft “conservation of energy” is given in Appendix A. Recent laboratory test results [2] indicate the expected thrust-to-power ratio for flight applications could be in the 0.4 – 4.0 N/kWe range, which is one to two orders of magnitude greater than current operational electric thrusters. This combination of characteristics – relatively high specific thrust combined with essentially zero on-board propellant requirement - suggest space mission performance levels significantly exceeding current capabilities.
A [Date Acquired: Oct 30, 2014] paper co-authored by Dr. White presented at the Institution of Electrical and Electronic Engineers: http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20140013174.pdf where he discusses short trips to the Jovian and Saturnian moons and "uncovers an energy paradox" (see Appendix A) .
.../... the point of this paragraph is to identify that the paradox can be created for any spacecraft using conventional propulsion as well as advanced propulsion.
Quote from: Rodal on 11/01/2014 11:35 pmA [Date Acquired: Oct 30, 2014] paper co-authored by Dr. White presented at the Institution of Electrical and Electronic Engineers: http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20140013174.pdf where he discusses short trips to the Jovian and Saturnian moons and "uncovers an energy paradox" (see Appendix A) .Quote from: Joosten & White.../... the point of this paragraph is to identify that the paradox can be created for any spacecraft using conventional propulsion as well as advanced propulsion.That ends the appendix A that "addresses" the apparent "issue" of energy conservation. There is no issue : energy conservation is broken every time we fly a rocket. Ok. Let's proceed to more interesting stuff...Only...Propellantlessbefore O----> +energy to spendafter O----->Action/reaction rocketbefore oo----> + energy to spendafter o--> o-----> expelled So in the later case, when taking into account the mass_energy of masses, there is energy conservation overall (in any inertial frame). In the former case there is no such conservation as soon as you choose an inertial frame where speed above some threshold.Said otherwise, in any given arbitrary inertial frame, for the classical rocket to give practical power at constant rate (pushing at constant speed) you have to replenish both energy & reaction mass from the said frame, can't have more energy than you put in. For the propellantless rocket, with thrust/power better than 1/c, then you just have to replenish in energy, and energy is light enough to be communicated from a "rest frame" to the rocket at lower cost than you get back from the rocket pushing.Perpetual motion of the first kind possible in the propellantles case, not in the classical action/reaction case. Not the same thing. Period.
I'm not seeing it that way. A Hall thruster is not propellant less. He never used the word propellant less to describe the paradox. I see a false paradox, which was created by bad methodology and bad math. Advanced propulsion does not equal propellant less propulsion.
Quote from: Mulletron on 11/02/2014 10:32 amI'm not seeing it that way. A Hall thruster is not propellant less. He never used the word propellant less to describe the paradox. I see a false paradox, which was created by bad methodology and bad math. Advanced propulsion does not equal propellant less propulsion."One of the issues to consider for a constant thrust system is the matter of conservation of energy."You can't have constant thrust with action/reaction scheme, because there can be a constant expelled mass flow for only so long. So for me this is broadly "we are talking about propellantless propulsion". And indeed any such propellantless scheme has an issue of energy conservation. In the terminology of this appendix, the Hall thruster is conventional, the EMdrive (propellantless whatever) is advanced.I see another spectacularly failed attempt at addressing the intrinsic issue with energy conservation of propellantless schemes, as bad as Shawyer's. Any serious physicist/engineer reading this appendix A will immediately see the plain absurdity of the argument, one way or another. This is not serious.
Quote from: Mulletron on 11/02/2014 10:32 amI'm not seeing it that way. A Hall thruster is not propellant less. He never used the word propellant less to describe the paradox. I see a false paradox, which was created by bad methodology and bad math. Advanced propulsion does not equal propellant less propulsion."One of the issues to consider for a constant thrust system is the matter of conservation of energy."You can't have constant thrust with action/reaction scheme, because there can be a constant expelled mass flow for only so long. So for me this is broadly "we are talking about propellantless propulsion". And indeed any such propellantless scheme has an issue of energy conservation. In the terminology of this appendix, the Hall thruster is conventional, the EMdrive (propellantless whatever) is advanced.I see another spectacularly failed attempt at addressing the intrinsic issue with energy conservation of propellantless schemes, as bad as Shawyer's. Any serious physicist/engineer reading this appendix A will immediately see the plain absurdity of the argument, one way or another. This is not serious.Propellantless scheme with better than 1/c thrust/power : either the ship taps into some energy source outside of it, or it is on its own energy and it uses tachyons. http://forum.nasaspaceflight.com/index.php?topic=29276.msg1275281#msg1275281A classical action/reaction scheme needs neither energy source exterior to ship nor tachyons to be energy conservative. The expelled mass that's used to get better than 1/c thrust/mass had to be accelerated at the given speed first is another way to see it, this kinetic energy of expelled mass (at the moment it is expelled) is sacrificed as well as the energy taken to give it velocity relative to ship's frame.
Quote from: Rodal on 11/01/2014 03:08 pmQuote from: Notsosureofit on 11/01/2014 02:01 pmGreat! Look at the drumhead expansion of the big end .002" copper FRP w/ resistve heating from the Cu loss!http://en.wikipedia.org/wiki/FR-4I need to know the boundary conditions for the 0.002" copper.Is the 0.002" copper a separate thin sheet of copper, or is the 0.002" copper thermally sprayed on the fiber-reinforced-polymer substrate and hence integrally bonded to it, or is the 0.002" copper adhered to the fiber-reinforced-polymer substrate ? Can the 0.002" be easily peeled apart from the polymer composite substrate?(Can one hold on to that 0.002" copper with pliers and peel it apart from the polymer composite substrate?The single sided Copper FR4 used looks thicker than 1/16". It may be 3/32" or 1/8" but the Copper is likely not any thicker than .020". The Copper is heat bonded to the FR4 using a heat curing epoxy. I base this assumption from my attempts to remove strips of Copper from PCBs. The Copper has to heated up to about 700 F before trying to peel it off.
Quote from: Notsosureofit on 11/01/2014 02:01 pmGreat! Look at the drumhead expansion of the big end .002" copper FRP w/ resistve heating from the Cu loss!http://en.wikipedia.org/wiki/FR-4I need to know the boundary conditions for the 0.002" copper.Is the 0.002" copper a separate thin sheet of copper, or is the 0.002" copper thermally sprayed on the fiber-reinforced-polymer substrate and hence integrally bonded to it, or is the 0.002" copper adhered to the fiber-reinforced-polymer substrate ? Can the 0.002" be easily peeled apart from the polymer composite substrate?(Can one hold on to that 0.002" copper with pliers and peel it apart from the polymer composite substrate?
Great! Look at the drumhead expansion of the big end .002" copper FRP w/ resistve heating from the Cu loss!http://en.wikipedia.org/wiki/FR-4
For what it's worth, I measure the FRP board at 0.060" and the copper cladding at 0.002". (the stuff I have here anyway)
I'd just like to clear up a couple of misunderstandings. To answer your red text: the Pioneer probes lose inertia according to MiHsC since they're moving out to lower accelerations, see longer Unruh waves, so a greater proportion of those waves are disallowed by the Hubble horizon. In the emdrive the difference is that the horizon itself changes from end to end. Both predictions are consistent with MiHsC, given the assumptions made. As for photons, special relativity (and experiment) say they have inertial mass. It is their rest mass that's zero. So it is logical and consistent to try and apply MiHsC to them. Can this be done in a way that still satisfies all the experiments performed to date? I don't know, but I'm curious about it..
Quote from: MikeMcCulloch on 11/02/2014 02:45 pmI'd just like to clear up a couple of misunderstandings. To answer your red text: the Pioneer probes lose inertia according to MiHsC since they're moving out to lower accelerations, see longer Unruh waves, so a greater proportion of those waves are disallowed by the Hubble horizon. In the emdrive the difference is that the horizon itself changes from end to end. Both predictions are consistent with MiHsC, given the assumptions made. As for photons, special relativity (and experiment) say they have inertial mass. It is their rest mass that's zero. So it is logical and consistent to try and apply MiHsC to them. Can this be done in a way that still satisfies all the experiments performed to date? I don't know, but I'm curious about it..Confining myself here only to the specific discussion (and not to MiHsC) of the statement that "photons are speed invariant." This statement is incorrect in general and contrary to what I was taught at MIT. It is well known that light travels at different speed in different media: Experiments show, that single photons travel through glass at the group velocity of light, which can be quite different from the speed of light in vacuum.It is classical (Newtonian) mechanics that demands that the momentum of the photons be greater in water than in air, but measurements show that the opposite relationship holds for their velocity.The view that photons are particles whose speed is invariant in any media and under all conditions is contradicted also by these recent experiments revealing a new state made possible with photons: http://www.princeton.edu/engineering/news/archive/?id=13459https://journals.aps.org/prx/pdf/10.1103/PhysRevX.4.031043I think that there is a confusion in the statement between the constant "c" (that of course, indeed, is an invariant constant) from General Relativity and the quantum description of photons in Quantum Mechanics.General Relativity does not deal with quantum particles like photons. Particles like photons are described by Quantum Mechanics.
On a separate note, why do the Pioneer probes get to lose inertial mass as they fly away from the solar system, ...