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#2860 by Stormbringer on 30 May, 2016 01:28
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http://nextbigfuture.com/2016/05/16-predictions-of-quantized-inertia.htmlQuote
May 27, 2016
16 Predictions of quantized inertia where experiments could validate the predictions and the theory
controversial, emdrive, mathematics, physics, predictions, quantum, quantum effects, science
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Dr. Mike McCulloch, Lecturer in Geomatics, had created a model for inertia called: Modified inertia by a Hubble-scale Casimir effect (MiHsC) or quantized inertia. Nextbigfuture covered it a few months ago. Mike uses it to explain the controversial emDrive.
The idea of inertia is that in a vacuum, where there is no friction, objects move along in a straight line at constant speed until you push on them.
MiHsC predicts a lot that has been seen already. MiHsC predicts 'specific' new effects that can be looked for more effectively. Some predictions have not had calculations to predict exactly would would be seen so they are more like ideas for experiments rather than rigorous predictions.QuotePredictions of quantized inertia:
1. In MiHsC inertial mass is enhanced when the peak wavelength of the Unruh spectrum (determined by acceleration) fits exactly within the Hubble scale. So for any accelerating/spinning object: solar system or galaxy, there should be some acceleration or radii with higher inertial mass because the Unruh waves fit exactly (resonate) and some with lower. This should give rise to subtle concentric patterns in these systems. For example, for Pioneer it would lead to tiny variations in the Pioneer anomaly.
2. In MiHsC as acceleration decreases the inertial mass drops towards zero (explains galaxy rotation without dark matter) so for any system ejecting mass into deep space at some point the inertial mass should dissapear and the gravity pulling it back should dominate. These systems should then have rings around them at the radius where accelerations are ~7x10^-10 m/s^2.
3. More generally, there should not exist any mutual acceleration below about 7x10^-10 m/s^2 today, and further back in time this minimum acceleration, a_min=2c^2/(Hubble scale), was higher, since the Hubble scale was smaller, so ancient (high redshift) galaxies should have greater spin for less visible mass.
4. The opposite case, for objects coming from deep space into the Solar system, or into galaxies, their acceleration is increasing so they should gain inertial mass by MiHsC and slow down anomalously, just like an inverted Pioneer anomaly, and of the same size (it will appear as though there's unseen mass at the outer edge of the system).
5. Along a spin axis the mutual acceleration with surrounding matter is zero so inertial mass should collapse for nearby objects there and produce unusual dynamics. For Earth this predicts the flyby anomaly, but it is hugely magnified for slow spinning system, eg: galaxies, and should result in axial jets (galactic jets?).
6. If an object in deep space, far from other objects (in the low acceleration MiHsC regime) spins or moves, then objects nearby (cosmically speaking) should tend to spin or move in the same sense. This is similar to the Tajmar effect in the lab, also predicted by MiHsC.
7. GPS satellites have a different mutual acceleration with the spinning Earth at the equator and pole, so they should show an small latitudinal dynamical anomaly.
8. In MiHsC, Rindler horizons destroy information behind them, so if we take this further, then for example the Rindler horizon of a rapidly-enough accelerating object may come close enough to block the gravity from eg, the Sun in a detectable way. For a 10cm diameter disc a spin of 23,000 rpm is needed to block the Sun.
9. If you super-cool an object to damp all acceleration, and then spin it (very fast) or for example 'jerk' electrons within it (eg: flash drive or superconductor passing its transition temperature) then its inertial mass (weight) should change depending on the size of the change in acceleration. For a 10cm disc an acceleration of 500,000 m/s^2 should reduce weight by 2%.
10. MiHsC breaks equivalence in a subtle way: two objects dropped in a Fallturm (Fall tower) would still fall together (so MiHsC won't show up in torsion balance tests) but they will fall ever so slightly faster than expected (for a 110m high tower they'll deviate from the expected position at the bottom by 7.5 nm). Also, a spinning object should fall more slowly.
11. If an object is given a huge acceleration, for example in the CERN LHC, (or a fast spin) the Unruh waves it sees (normally light years long) could become short enough that our technology can get a handle on them (a few km). Either EM-radiation or metamaterials could be used to interact, damp or deflect those Unruh waves (their Em-component) and thereby control the inertial mass of the object.
12. MiHsC predicts the emdrive (if it is assumed that photons have inertial mass) by saying crudely that more Unruh waves fit into the wide end than the narrow. It follows that if the narrow end was fine-tuned to fit the individual Unruh waves better, despite being narrower, then the emdrive thrust should be reversible. MiHsC also predicts that the speed of light should change inside the emdrive.
13. Since MiHsC predicts that all waves that don't fit into the Hubble scale are disallowed, then this should be the case for waves of thermal radiation too. Hence mind-buggeringly cold objects should radiate very slightly less than expected. At 100pK the effect should be one part in 10^20.
14. MiHsC predicts a minimum acceleration in nature, 6.7x10^-10 m/s^2, the acceleration for which the Rindler horizon reaches the Hubble horizon and can't be any larger (this explains cosmic acceleration) and MiHsC also predicts a maximum acceleration of 10^52 m/s^2 when the Rindler horizon shrinks to the Planck area. Acceleration and mass should be quantised near these extremes.
15. The tiny minimum acceleration of MiHsC occurs because at very low accelerations Unruh waves are disallowed because they are bigger than the Hubble scale. If we can manufacture a small 'informationally closed area', we could boost this acceleration.
16. Collapsing sonoluminescent bubbles, atoms suddenly confined, or core-collapsing supernovae will see their Rindler horizons shrink and this will release new heat energy. Like water from a squeezed wet towel, whenever you shrink a Rindler horizon by accelerating an object, the horizon releases energy (which usually turns up as inertial mass). Manufactured 'squeezed horizons' are therefore a potential new source of energy.
SOURCE - Predictions from the Edge by Mike McColloch -
#2861 by AnalogMan on 30 May, 2016 01:54
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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.
Ceramic machine screws/bolts/nuts are available if you can afford them.
For example (not necessarily the cheapest) see:
http://www.amazon.com/Ceramic-Machine-Finish-External-Threads/dp/B00DD44VPA -
#2862 by mikegem on 30 May, 2016 02:04
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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.
Ceramic machine screws/bolts/nuts are available if you can afford them.
For example (not necessarily the cheapest) see:
http://www.amazon.com/Ceramic-Machine-Finish-External-Threads/dp/B00DD44VPA
I've used Teflon hardware in high intensity microwave fields at 2.45GHz and 915MHz. Teflon tan delta is very low and I never saw evidence of heating. I bought from McMaster-Carr, but they're available elsewhere. I've also used ceramic hardware (alumina), which works. When I was doing this work, ceramic hardware was much more expensive than Teflon. Haven't looked lately. -
#2863 by jamesds on 30 May, 2016 04:13
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Long time reader, first time poster here.
I'm not qualified to comment on any of this (software engineer with an armchair
physics fascination), but I will anyway.
So here's my hypothesis as to an explanation for Emdrive thrust.
Imagine a cavity injected with high frequency EM radiation, sitting on the
ground in Earth's gravational field.
There is an ever so slight difference in gravitational field strength between
the top and bottom of the cavity - stronger at the bottom than the top. For a
10cm high cavity in Earth's gravity at sea level the difference in field
strength is about 1 part in a million between the top wall and the bottom wall
(back of napkin calculation).
Relativity says that light is red-shifted in a stronger gravitational field.
This means that the momentum of the photons hitting the bottom of the cavity
will be less than those hitting the top. This difference in momentum produces
a force towards the top of the cavity (away from the center of the Earth). This
results in an asymmetric force between the top and bottom of the cavity and
hence thrust.
What's potentially interesting about this is that the thrust per KW will be
subject to an inverse square law of the distance from a massive body because
the delta between the gravitational field strength between the top and bottom
of the cavity will decrease and tend to zero the further the cavity is away
from a massive object.
This hints that energy may be conserved by virtue of the fact that more energy
will be required to produce a constant thrust as distance from a massive body
increases.
This also hints that momentum is conserved because the momentum the photons
lose due to red shifting is conserved by moving the cavity.
Another observation is that the efficiency of the emdrive will be greater when
the delta between gravitational field strength between the top and bottom of
the cavity is greater - this means increasing the height of the cavity should
increase performance.
Another observation is that higher Q implies higher thrust: multiple reflections
increases amount of differential red shifting.
This hypothesis also implies that perfectly horizontal thrust will not be
possible due to gravitational force being a vector. Given that concensus has
not been reached that thrust is larger than error bars, I'm not sure if this
has been ruled out.
Doing the math for this is beyond my ability. It would be great if someone
could do some modeling.
Anyway, I'm happy for this idea to be torn apart. It came to me over lunch
just now and I just had to write it down.
If you read this far: thank you for giving a layperson a chance to air his
thoughts!
Cheers,
James.
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#2864 by zen-in on 30 May, 2016 05:22
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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.
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.
The 4250 V. pulse train will have a frequency of 60 Hz, not 120 Hz. While I have been shocked countless times (once by 10 kV DC superimposed on 120 VAC, from one hand to the other!!) I have no interest in playing with magnetrons. If I was going to I would build a different kind of supply. The voltage doubler will just increase the voltage on the magnetron, leading to early failure and possibly a shift in frequency. A better method would be to use a full wave rectifier circuit. That will supply close to the same voltage and with a lot less ripple. HV capacitors can be used to filter this ripple and will not be subjected to as much dissipation losses as the doubler caps. So they will be less likely to go pop in the night. The diodes are nothing special but do have to withstand 5 kV. I have not seen the inside of a microwave PS and am assuming most are just a big 60 Hz transformer with a HV winding and a low voltage high current filament winding. If that is what you have then you can put a variac in front of it to reduce the output voltage. Reducing the AC voltage going into the PS will reduce the power dissipated a lot, since P = V2/R. That might shift the frequency of the magnetron and if it's your lucky day the shift may be down.
The filament winding would have to be disconnected from the HV - end if a full wave bridge rectifier is used. That filament lead would connect to the - side of the rectifier bridge instead. I don't know how easy it is to modify microwave oven power supplies.
Care has to be taken with wiring the HV diodes because leakage currents can result in erratic behavior. Screw down terminals are no good above a few hundred volts. The best method I have seen uses ceramic standoffs screwed to a fiberglass board. I have used 1/16" Teflon sheet with holes punched in it for similar circuits. FR4 sheet can also be used but most PCB material is not suitable. -
#2865 by SeeShells on 30 May, 2016 05:57
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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.
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.
The 4250 V. pulse train will have a frequency of 60 Hz, not 120 Hz. While I have been shocked countless times (once by 10 kV DC superimposed on 120 VAC, from one hand to the other!!) I have no interest in playing with magnetrons. If I was going to I would build a different kind of supply. The voltage doubler will just increase the voltage on the magnetron, leading to early failure and possibly a shift in frequency. A better method would be to use a full wave rectifier circuit. That will supply close to the same voltage and with a lot less ripple. HV capacitors can be used to filter this ripple and will not be subjected to as much dissipation losses as the doubler caps. So they will be less likely to go pop in the night. The diodes are nothing special but do have to withstand 5 kV. I have not seen the inside of a microwave PS and am assuming most are just a big 60 Hz transformer. If that is what you have then you can put a variac in front of it to reduce the output voltage. Reducing the AC voltage going into the PS will reduce the power dissipated a lot, since P = V2/R. That might shift the frequency of the magnetron and if it's your lucky day the shift may be down.
I was reposting what ElisabethGreen had posted and the pulse train timing is not correct but the rest is on the filament. Thanks for correcting that.
My first series was from a inverter (Panasonic) and this second series is controlled from a variable HV DC power supply. I also opted for the variac for finer control over the voltages.
http://www.robkalmeijer.nl/techniek/electronica/radiotechniek/hambladen/qst/1985/04/page32/index.html
fig 2 is close.
HV is something to respect and I've not been hit but once from a HV cap. I've worked with much higher voltages and back in the tube days the HV for plates on tubes and the old cathode ray tube TVs.
BTW you're right the power supply in some microwaves is built as cheap as they can and use the old iron xformer.
Shell
Shell
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#2866 by zen-in on 30 May, 2016 06:33
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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.
Ceramic machine screws/bolts/nuts are available if you can afford them.
For example (not necessarily the cheapest) see:
http://www.amazon.com/Ceramic-Machine-Finish-External-Threads/dp/B00DD44VPA
I've used Teflon hardware in high intensity microwave fields at 2.45GHz and 915MHz. Teflon tan delta is very low and I never saw evidence of heating. I bought from McMaster-Carr, but they're available elsewhere. I've also used ceramic hardware (alumina), which works. When I was doing this work, ceramic hardware was much more expensive than Teflon. Haven't looked lately.
I don't see why you can't use stainless screws. In air/vacuum a 2.4" long screw will act like a 1/2 wave antenna and will just be a high impedance to the 2.45 GHz RF. Since it will be in a dielectric the length will have to be recalculated. I'm sure there is some length that will be invisible to the RF. -
#2867 by dustinthewind on 30 May, 2016 08:00
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Long time reader, first time poster here.
...
There is an ever so slight difference in gravitational field strength between
the top and bottom of the cavity - stronger at the bottom than the top. For a
10cm high cavity in Earth's gravity at sea level the difference in field
strength is about 1 part in a million between the top wall and the bottom wall
(back of napkin calculation).
...Relativity says that light is red-shifted in a stronger gravitational field.
This means that the momentum of the photons hitting the bottom of the cavity
will be less than those hitting the top. This difference in momentum produces
a force towards the top of the cavity (away from the center of the Earth). ...
This hypothesis also implies that perfectly horizontal thrust will not be
possible due to gravitational force being a vector. Given that concensus has
not been reached that thrust is larger than error bars, I'm not sure if this
has been ruled out.
...
James.
Hi James, and I am sure you are welcome here. You have an interesting point about how small the change is in the gravitational field along the distance of the cavity. I would suspect that the earths gravity would have a negligible effect on the momentum of the photons if there was an effect, but depending on the hypothesis.
I had a post earlier where I assumed a K value of 4 at one side of the cavity which in my opinion is a bit extreme but on second thought the wavelength in the cavity is visibly stretched.click message link to see the older post I referenced.
I would suspect the effect I was considering would be negligible if K did vary inside the frustum (but then again, consider the stretch of the wavelength inside the frustrum). The K value was based on the polarizable vacuum concept and I just did that to give an example of how a trapped bouncing ball that has its properties changed in mid flight by the K value could possibly accelerate a cavity. That was assuming that for some reason inside the cavity the stretching of the wavelength was some how paralleled to the K value which may be quite a stretch.
What I found interesting was that the stretching of the wavelength one would assume the photons lose momentum, but by the Polarizable Vacuum concept they actually gain momentum. Their mass grows faster than the velocity slows down as light approaches a gravitational object. I think WarpTech was actually one of the first to bring up the concept if not others before, and I should probably go back and read some of his old posts on it. -
#2868 by SeeShells on 30 May, 2016 12:40
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NSF-1701A Update
Very quick data analysis.
Attached is dataset #2 for Frustum pointed down. Data collected after 10 minute warmup period. Additional channel added, Open, for noise analysis.
20 min run sample
6036 samples
caculated error bar
ave linear trend
Added: VERY NICE WORK.
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#2869 by RotoSequence on 30 May, 2016 13:25
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NSF-1701A Update
Very quick data analysis.
Attached is dataset #2 for Frustum pointed down. Data collected after 10 minute warmup period. Additional channel added, Open, for noise analysis.
20 min run sample
6036 samples
caculated error bar
ave linear trend
Added: VERY NICE WORK.
The trendline for the current data set fits wholly inside the calculated error bars? -
#2870 by Monomorphic on 30 May, 2016 13:35
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I found two things that don't seem to heat up in the microwave that can be used to fasten the HDPE insert. These small black plastic push screws and believe it or not, hot glue. I microwaved both of these separately for 30 seconds each and there was little to no heating. The ceramic plate heated up before these two.
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#2871 by SeeShells on 30 May, 2016 13:37
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NSF-1701A Update
Very quick data analysis.
Attached is dataset #2 for Frustum pointed down. Data collected after 10 minute warmup period. Additional channel added, Open, for noise analysis.
20 min run sample
6036 samples
caculated error bar
ave linear trend
Added: VERY NICE WORK.
The trendline for the current data set fits wholly inside the calculated error bars?
Yes it did. Remember his Frustum was pointed up vertically, this is just for baseline error data, not intended to measure force or acceleration.
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#2872 by Rodal on 30 May, 2016 14:31
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...
Professor Melcher at MIT (and previously Prof. Chu and others at MIT's Radiation Laboratory) was already showing decades ago in MIT classes that the Einstein-Laub formulation of electrodynamics is invalid since it yields a stress-energy-momentum tensor that is not frame invariant. (It is an interesting historical vignette that Einstein did not realize this at the time he wrote the paper with Laub)
The momentum of light in media remains one of the most controversial topics in physics [1–6]. The debate has continued for more than a century since Minkowski and Abraham formulated 4 × 4 energy-momentum tensors in the early 1900s [7–9].
https://www.researchgate.net/publication/292342272_Kinetic-energy-momentum_tensor_in_electrodynamics
They do credit Prof. Chu with the correct invariance relations. But that is one of the reasons why Prof. Chu at MIT developed his formulation.
This was known by students that listened to the lectures of Prof. Chu and Melcher at MIT
Reference: Prof. Melcher's masterpiece "Continuum Electromechanics" which he wrote in 1972-1973 while he was in sabatical at Cambridge University working with Sir Taylor and G. Batchelor
Correct, although The Einstein-Laub formulation of electrodynamics does work in a real world lab. 1973, Ashkin and Dziedzic performed a experiment in which they focused a green laser beam on the surface of water and saw what they called "the toothpaste tube effect" where a bulge appeared in the surface of the water. Using a Lorentz formula the existence of expansive and compressing forces effectively cancel out, negating a possible bump forming on the water surface. The real world lab test showed where pure theoretical extraction detailing out why there are thrusts from a asymmetrical cavity are lacking. . .
This is why lab data is king right now.
Shell
Back to work... will be on later. Have company helping me move my new frame for the lab.
Ashkin and Dziedzic used an argon-ion laser source to investigate the pressure on solid dielectric spheres immersed in liquid, and the pressure on a liquid-air interface owing to the passage of a beam of radiation.
Ashkin and Dziedzic's experiment cannot distinguish between the various stress tensors (Abraham, Minkowski, Einstein-Laub, etc.), since it gives no information about the direction of the local surface force.
Ashkin and Dziedzic observed the liquid interface to bend outwards in the liquid both when the light enters and leaves the liquid. This is contrary to the conservation law he derives from a Lagrangian formalism, and which predicts inward bending.
Loudon (see: Loudon, R., Radiation pressure and momentum in dielectrics. Fortschr. Phys., 2004. 52(11-12): p. 1134-1140) concluded that:Quote from: LoudonThe Ashkin and Dziedzic experiment observed an outward bulge on an illuminated water surface, apparently consistent with the sign of the Poynting surface force and the value of the Minkowski momentum. In agreement with Gordon, it is shown here that the effect is governed by a radial force and it provides no information on the longitudinal force associated with the linear momentum of light.
(bold added for emphasis)
One of the reasons why this Abraham Minkowski controversy persists is because of problems with the experiments:
1) Most experiments in the Abraham-Minkowski controversy (including Ashkin and Dziedzic) ignore electrostriction and magnetostriction. A term should be added for the Helmholtz electrostriction term to Abraham’s and Minkowski’s tensor whenever necessary. Both Abraham and Minkowski’s tensors do not describe electrostriction or magnetostriction. Their tensors, therefore, are unable to give a complete description of the local electromagnetic state in the medium. It is unfortunate that electrostriction and magnetostriction are ignored, as one of the things that Prof. Woodward has realized with his Woodward/Mach Effect experiments is the importance of electrostriction or magnetostriction. It can be misleading to perform an experiment and extract conclusions without assessing the significance of electrostriction or magnetostriction.
2) The problem with Abraham-Minkowski experiments performed to date (and this goes also for EM Drive experiments) is that they are usually trying to measure only one term of the equation of motion: many times the force due to change of the electromagnetic momentum with time is not considered; or are trying to measure a boundary of a fixed block of dielectric material – so it is very difficult to consider all forces at the boundary. Instead of resolving the problem, contradictory experimental results have often clouded the picture further, because of incomplete analysis of very small forces, where not all the forces are properly taken into account.
------------------------------
At MIT, Professors P. Penfield Jr., H.A.H., Electrodynamics of Moving Media. 1967, Cambridge,Mass.: MIT Press. 241-243 provided a very detailed discussion showing that the force densities each comprise about 20 terms, most of the terms correspond to very small forces.
In Abraham-Minkowsk experiments, the majority of these forces are being ignored by the authors !
Authors in China, more than 50 years after MIT's work, are re-discovering this:
http://arxiv.org/pdf/1504.06437
Analytic derivation of electrostrictive tensors and their application to optical force density calculations
Wujiong Sun1,2, S. B. Wang2, Jack Ng3, Lei Zhou1, and C. T. Chan2*
1 State Key Laboratory of Surface Physics, Key Laboratory of Micro and Nano Photonic Structures (Ministry of Education), and Collaborative Innovation Center of Advanced Microstructures, Fudan University, Shanghai 200433, China
2 Department of Physics and Institute for Advanced Study, The Hong Kong University of Science and Technology, Clear Water Bay, Hong Kong
3 Department of Physics and Institute of Computational and Theoretical Studies, Hong Kong Baptist University, Hong Kong -
#2873 by RERT on 30 May, 2016 14:40
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rfmwguy -
Looked at your first set of data. A few observations/comments:
1. I was quite surprised to see the Power signal move from a square wave to more like a sawtooth over the length of the experiment. There are also some strange (but quite isolated) anomalies in the power stream, especially in the first third of the data. Any idea what's going on?
2. As a result of the above, the mid-term average of the power is not static, but slowly rises over most of the test. See the attached excel chart showing the 125 point ma of power.
3. Interestingly, at least just by eye, the beam deflection then seems related to average power: see the above chart again.
I guess 3, if verified, might be relevant to the comparison of results where average power is not the same.
Cheers,
R.
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#2874 by zen-in on 30 May, 2016 15:52
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NSF-1701A Update
Attached is dataset #2 for Frustum pointed down. Data collected after 10 minute warmup period. Additional channel added, Open, for noise analysis.
What is the data in each column?
Relative time: Is this in Seconds? I assume it represents the time delta between each row's data.
Time Stamp: agrees with Relative time
beam: No idea what this is. Is it a force, displacement? How is it calibrated?
power: Is this RF power On/OFF? Should it be considered a digital value?
open: No idea what this is. What units would it have and how is it calibrated?
Without more information I can't make any sense of this data. Even noise has units.
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#2875 by dustinthewind on 30 May, 2016 16:27
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I found two things that don't seem to heat up in the microwave that can be used to fasten the HDPE insert. These small black plastic push screws and believe it or not, hot glue. I microwaved both of these separately for 30 seconds each and there was little to no heating. The ceramic plate heated up before these two.
Glass if you get it hot first and then stick it in the microwave it will absorb microwaves though cold it won't. So there is the possibility if they get hot enough the spectrum they absorb could shift. Just something to consider but that isn't saying they will. -
#2876 by dustinthewind on 30 May, 2016 17:49
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This is one EM drive test build I was considering. It uses a phase lock loop, eliminates noise, would hopefully be testable at low powers, and hopefully eliminate problems with buoyancy and thermal convection thrust via the back and forth movement.
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#2877 by Monomorphic on 30 May, 2016 18:25
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I had to move the monitoring station into the adjacent room, as I expected might happen. As soon as the laser would become still, and I moved forward in my chair to activate the spec analyser and open broadcaster, that was enough to cause the pendulum to start moving. I also added a mirror to the webcam view so I can still see into the room.
Simply velcroing the first surface mirror to the beam just didn't cut it. So I built an adjustable mount so it's easier to align the laser with the ruler ~30 feet away.
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#2878 by rq3 on 30 May, 2016 20:12
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I had to move the monitoring station into the adjacent room, as I expected might happen. As soon as the laser would become still, and I moved forward in my chair to activate the spec analyser and open broadcaster, that was enough to cause the pendulum to start moving. I also added a mirror to the webcam view so I can still see into the room.
Simply velcroing the first surface mirror to the beam just didn't cut it. So I built an adjustable mount so it's easier to align the laser with the ruler ~30 feet away.
Monomorphic, I love your set-up. Just a suggestion on the mirror, based on many hours optically aligning telescope mirrors and high power lasers.
The mirrors are almost always mounted on 3 screws, mounted 120 degrees apart. That's the minimum to define an adjustable plane (unless you go for one fixed pivot point and only two adjustment screws). Four screws interact in weird ways.
Adding some kind of fairly large, round, preferably knurled head to the screws makes alignment infinitely easier. And the finer the screw thread, of course the finer the adjustment. A human finger can actually resolve about 100 nanometers by touch (yes, nanometers), and a knurled knob gets the extra tool (the phillips head screw-driver) out of the "feedback loop".
See McMaster-Carr for "thumb-screws" and "knurled knobs". Or just epoxy a wood disc (sawn off dowel) to the screw heads. A couple of lubricated thin washers under each screw head will also make the adjustment much less prone to stiction. -
#2879 by Monomorphic on 30 May, 2016 21:13
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I forgot to show an image of the newly braided leads. Here you go!
I'm using 10kV stranded wire, so it's very flexible.
