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#1500 by rfmwguy on 09 Jan, 2016 01:54
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The True Nature of Matter and Mass | Space Time | PBS Digital Studios
"Photon box" = frustum?
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#1501 by JonathanD on 09 Jan, 2016 02:22
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My concern of late is that, as long as there aren't more well funded, institutional, conclusive tests in a hard vacuum showing the presence of force (or its lack thereof) after rigorous attempts to expunge all sources of noise, all DIY experiments will continue to be tainted by the suspicion of systematic experimental error. Because they are made on air, and that always implies the presence of thermal-convection forces. And even more if the forces measured are comparable with those known to arise from thermal/convection phenomena on air.
Well, we have actually 2 institutional efforts for testing this on a vacuum so far. NASA EagleWorks' and Martin Tajmar's at Dresden.
NASA's one is why many of us are still excited and paying attention to the Emdrive. Dresden's are way more inconclusive, and IMO they look like a negative.
Therefore the ball still is at NASA EW, from who we are expecting for a peer-reviewed and replicated confirmation (or refutation), and maybe with Tajmar's team, in case they try to get better thrust from their Emdrive setup (or a new one).
I'm not dissing DIY efforts, though. But let's be honest: only after a lab performs a clear replication in a vacuum, this phenomenon would be taken more seriously in academia.
That or a mythical demonstration of an Emdrive moving all by itself or shooting through the roof (which I notice, TT said has plans to do. I'm really looking forward for that. The self propelled Emdrive, not the one flying through the roof).
This is a post of great sense. In my humble layman opinion I would say, given a scenario where there *might* be an environment wherein there *may* be curious results of undetermined cause (be it thermal, or other yet-to-be-known causes that could completely remain within the understood realm of physics), the most official and professional lab may benefit from the breadcrumbs left by the trial-and-error DIYs.
Put bluntly, if Eagleworks can't explain what is happening, even well-documented DIY experiments may ultimately be helpful in both eliminating some possibilities, and perhaps more importantly, serving to raise awareness of the phenomenon itself. Of course more broadly, there is no shortage of fascinating avenues of science that are still not fully explored (I think my brother-in-law did his PhD physics work in spin glasses, which I'm *still* trying to understand), in part because no one has the interest (aka funding) to pursue them. So there is something to be said for multiple efforts, especially given the internet venues available today.
I consider myself to be in the camp that I think there is a chance there is a unique situation occurring that involves conventional laws that we don't yet have the context for understanding the cause of thrust (I'd include quantum or standard model in that), or the (obviously) more predominant chance is that it's a thermal effect. I'm not big on the idea that it's new physics, quantum mechanics is strange enough. But I'm not a physicist, so wtf do I know, other than reading a lot and trying to understand this stuff just because I find it fascinating.
All of that is my attempt to explain why I think the continued disciplined efforts of the DIYers is more than worth it from a universal sense (although I am in complete awe of their personal dedication and the time and $ impacts it entails, not to mention their ability to work with microwave sources without harming themselves or others!).
I don't think I had enough parenthesis in this post (so I'll add one more set
)
Eagerly lurking, good luck everyone.
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#1502 by SeeShells on 09 Jan, 2016 02:31
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#1503 by zen-in on 09 Jan, 2016 02:36
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At Digilab, a Cambride MA FTIR spectrometer manufacturer we used DG Eclipse S/130 minis. They had a 10 Gig Winchester drive; so named because of the removeable media. When it was calculating an FFT the hard drive made a characteristic rhythmic noise that would go on for as long as an hour sometimes, since the data was cached on the disk. We also used DG Novas for testing our interface boards. They used core memory so the paper tape loader stayed intact after a power cycle. The Eclipse had boot proms, very pricey in 1978 and used solid state memory. To make a hard-copy of the spectra, we used an ink-jet printer; a rarity back then.
That was almost certainly a 10MB Winchester drive, not 10gig! The first 1GB drive I ever saw was in 1988 - about 6"x12"x24" and was $25,000 (for a VAX 8340 - quad processors @~8Mhz each!). We had 8 of these HD's - 4GB with a shadow pair. $200K in hard drives!! That would be about 3,300 TB today
Yes! I'm so used to saying Gigabyte or Terrabyte now. I'm not sure if it was10 GB!! I did it again! I mean 10 MB on each platter, just the bottom drive, or both, but the whole thing took a pallet jack to move. Some minicomputers back then could only directly address 32 kwords of memory because every memory instruction had an indirect bit, usually bit15. Before Digilab I worked for Measurex, an early silicon valley company that sold process control systems. They used HP 2100 series minis. In 1977 I assembled a personal computer with a keyboard, simple graphics display, and a hack of HP's Magnetic Tape Operating System working on cartridge tapes. I could compile programs in Algol or Fortran! -
#1504 by Bob Woods on 09 Jan, 2016 02:42
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I'm not dissing DIY efforts, though. But let's be honest: only after a lab performs a clear replication in a vacuum, this phenomenon would be taken more seriously in academia.
That or a mythical demonstration of an Emdrive moving all by itself or shooting through the roof (which I notice, TT said has plans to do. I'm really looking forward for that. The self propelled Emdrive, not the one flying through the roof).
Me? I'm looking for a video of Shell's drive blasting though a wall with a case of Red Bull being dragged behind!
THAT would make the evening news....
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#1505 by aero on 09 Jan, 2016 02:52
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I wonder if someone competent with software would like to step up to finding/installing/learning a multiphysics package. There are several free packages available but COMSOL's free package is only a free trial unless the company could be persuaded to donate as an educational public service.
I found this which describes some of the difficulties involved in creating a multiphysics package from scratch.
https://www.researchgate.net/post/Where_to_find_open-source_Multiphysics_Simulation
And I found this which describes some of the free packages available.
https://en.wikipedia.org/wiki/Multiphysics
Wikipedia also has a comparison table with many packages, but I can't find the link in the time I have availale. -
#1506 by TheTraveller on 09 Jan, 2016 02:57
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That you can't solve this set of equations in the under cut off volume doesn't mean there can't be thrust at all.I agree with 1) but what is the evidence that leads to 2)?
Why does Shawyer suggest to keep the small end above cutoff?
It is stated in Roger's thrust equation:
Thrust = (2 * Qu * Df * Power) / c
Where Df is as attached and is where the small end cutoff comes into the equation. With the small end in cutoff, there is no thrust.
Please refer to the 2nd and 3rd attachments as well
(If there was ever thrust like discussed and not other effects like Lorentz force or whatever)
As far as I know Shawyer's Df and thrust equations are not proven till now.
All discussed thrust equations for conical cavities leads to larger thrust the closer the narrow end of the cavity is in relation to it's apex (mathematically singularities at null distance).
Some threads ago we had a huge discussion especially of the effects of evanescent waves.
Question: Was this been tested by Shawyer and his company or is it his intuitive opinion that it would not work with an undersized end of the cone, just below cutoff diameter?
Roger has told me and others that the small end MUST operate above cutoff or no thrust. Would expect that was from coal face experience plus there is no Df if the small end is at or below cutoff.
So his advise matches his equation. -
#1507 by SeeShells on 09 Jan, 2016 03:07
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The True Nature of Matter and Mass | Space Time | PBS Digital Studios
Since we're doing basics, you're going to love Lorentz and many of our readers here when they hear of Lorentz causing issues in the measurements it goes much further than just that.
"Photon box" = frustum?
Shell
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#1508 by SeeShells on 09 Jan, 2016 03:09
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Be better if if was just a bull.
I'm not dissing DIY efforts, though. But let's be honest: only after a lab performs a clear replication in a vacuum, this phenomenon would be taken more seriously in academia.
That or a mythical demonstration of an Emdrive moving all by itself or shooting through the roof (which I notice, TT said has plans to do. I'm really looking forward for that. The self propelled Emdrive, not the one flying through the roof).
Me? I'm looking for a video of Shell's drive blasting though a wall with a case of Red Bull being dragged behind!
THAT would make the evening news....
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#1509 by A_M_Swallow on 09 Jan, 2016 05:38
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A question for the various DIYers out there.
I've got some CAD skills (Solidworks) and I have been thinking lately about how that might possibly aid these endeavors going on. One thing I realized is that one of my professional 3D printer sources (ShapeWays) can do metal printing of various sorts, including polishing of external surfaces. If it would be helpful for me to CAD up some frustums based on your desired dimensions, I can do various things like integrate cooling devices (fluid channels, peltier mounts, etc), and other things. Chances are decent though that unless an unpolished surface is acceptable the inside of the frustum, that the big end will need to be detachable, which I can do as well. I don't have the software with me at the moment, but to some degree I believe I have some of the modeling tools, such as thermal and whatnot available to try out on the models. I somewhat doubt I have any radio packages, though I will look at that just in case.
All that said, it seems at least ShapeWays is limited in their size to (27.918 x / 25.908 y / 27.928 z, cm), which does not seem sufficient for most of the attempts I am aware of, such as rfmwguy's. However, if someone were desiring a much smaller frustum (from what I've gathered, this seems to mean higher frequency?), this could be helpful.
Let me know what you all think about this.
-Mazon
There was somewhere in this forum, or perhaps reddit, someone who wanted to do this using a laser as I recall. That would be more a fiber optic approach, but if RF works in any frequency, shorter frequencies would work. NXP has some tech in the 77 GHz range that would be match your dimensions, but I'm unaware of a builder actively working in shorter wavelengths. The upside is the transmitters look like solid state devices which would make things easier in one sense, but lower power which would make things worse in another. Perhaps someone could source some surplus police radars in the Ka-band and try a build with your capabilities?
Most of the experiments are performed using microwaves tuned to the frequency reserved for microwave ovens. The advantages are there are no problems with interference jamming radio messages and cheap mass produced components are available. Cheap optical components are available for infra-red communications lasers. The lasers have wavelengths around 870 nm and 930–950 nm. -
#1510 by Mulletron on 09 Jan, 2016 08:10
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The True Nature of Matter and Mass | Space Time | PBS Digital Studios
"Photon box" = frustum?
I'm glad PBS put out that photon in a box video. PBS's reach is far and wide, it's bound to get a few people thinking about the EmDrive. -
#1511 by Flyby on 09 Jan, 2016 08:30
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A question for the various DIYers out there.
Keep in mind that there are many different 3Dprinting technologies, each with their own purpose and market targets. Make sure you get the right technology for the right job. Nothing is straightforward with 3dprinting.. speaking from experience here..
I've got some CAD skills (Solidworks) and I have been thinking lately about how that might possibly aid these endeavors going on. One thing I realized is that one of my professional 3D printer sources (ShapeWays) can do metal printing of various sorts, including polishing of external surfaces. If it would be helpful for me to CAD up some frustums based on your desired dimensions, I can do various things like integrate cooling devices (fluid channels, peltier mounts, etc), and other things. Chances are decent though that unless an unpolished surface is acceptable the inside of the frustum, that the big end will need to be detachable, which I can do as well. I don't have the software with me at the moment, but to some degree I believe I have some of the modeling tools, such as thermal and whatnot available to try out on the models. I somewhat doubt I have any radio packages, though I will look at that just in case.
All that said, it seems at least ShapeWays is limited in their size to (27.918 x / 25.908 y / 27.928 z, cm), which does not seem sufficient for most of the attempts I am aware of, such as rfmwguy's. However, if someone were desiring a much smaller frustum (from what I've gathered, this seems to mean higher frequency?), this could be helpful.
Let me know what you all think about this.
-Mazon
Running a 3Dshop (marketing/architecture focus) myself and knowing quite well what's on the market today, I'd suggest to verify what type metalprinting Shapeways offers. (you can find it at the bottom of their specs sheets)
http://www.shapeways.com/materials/steel
What you certainly do not want is their stainless steel, because that's a manufacturing technology that needs high temperature curing, which alters the physical dimensions of the object considerably.That's because the steelpowder is first glued together with a binder, then removed from the printer and further cured in a high temperature oven...it alters your original dimensions. For aesthetic/ornamental applications this is of little concern, but I do not think it is wise to use for engineering applications.
Most of their metal (gold, silver, bronze, brass, etc) printing is size limited because they're using a highresolution wax printer. They first make a casting mold, which means any normal metal casting shrinkage also applies to it.
Only their aluminum printing is done with a powder/laser combination but I'm sure the rough and porous surface would need some extra work for it to be used as an EM-frustum. Considering the dimensions you've put forward, I suppose this is the technology you were referring to ?
A secondary concern i have is the potential thermal warping, especially if the cone's top/bottom circle is not structurally locked in place.
It is my feeling that you should look for companies that have specialized in technical/industrial metal 3Dprinting.
Shapeways is focused on consumer products and have a very different approach then a company that's more engineering oriented. Except for their jewelry 3dwaxprinters non of their technologies have the needed engineering accuracy needed.
There are technologies on the market that can combine 3dprinting and milling to achieve superior results. Or you could try to find a welding 3Dprinter. Those are the type of printer that will give you exactly what you want... but... it wont be cheap because those type of 3Dprinters cost many hundred thousands of euro's/dollars. As end client, you'll pay for that...
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#1512 by RERT on 09 Jan, 2016 09:37
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A few things caught my eye:
1) Dr.Rodal: in post 1488 you imply that currents in the frustum are significantly lower than 10^4 A. I have to agree with your earlier remarks that we can't just assert such things, but need some calculations to provide scale. Can you outline a calculation of what you think the skin currents in the frustum actually are, say for 1000w of RF input? I've previously calculated, and I believe posted, a calculation based on the RF power being dissipated as heat by a bulk current in the copper. The number is in the range of 1000's of amps.
2) a few posts later, someone posted that the community is not 'machine heavy'. I have to disagree: we all carry an early 80's supercomputer in our pockets! The problem then becomes getting someone under 30 to join the forum, and write us an app!
3) my first job was being system manager (dogsbody) on a pair of VAX 11/750 test machines, believe it or not called "Sodom" and "Gomora" (which are or were two towns in the Middle East). Who'd a thunk it...
R. -
#1513 by frobnicat on 09 Jan, 2016 09:59
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Conservation of Energy Question:
As I understand it, the objection here is that constant thrust at the levels claimed for the EM Drive lead directly to a violation of Conservation of Energy. However, suppose the thrust is NOT constant, but instead 'crashes' before reaching that point?
I am thinking here of a 'longer cycle.' Something on the order of 30-40 seconds of high 'thrust,' followed by an unavoidable 'crash' of at least several minutes with no thrust, yet still drawing power, then another 30-40 seconds of 'thrust,' followed by another 'crash.' A 'charge / discharge' cycle. To maintain 'constant acceleration,' you'd need several (10? 20?) EM Drives working in a timed sequence, and a corresponding increase in required power.
Does this represent a valid workaround for Conservation of Energy?
No. Unless it makes average thrust per power < 3.33µN/kW (for the whole system considered).
So, say you start at .1N/kW=100000µN/kW (where EM drive would start to be competitive with ion thruster, given contemporary flight ready sources of power -i.e. not advanced fission or fusion...-) and this is only valid for 1/10th of the time and during 9/10th each thruster still has to consume same nominal power (as per your hypothesis "yet still drawing power", which is hardly motivated : why not just switch off when 'crash' occurs and let things cool down to same state as that allowing a first pulse ?) then that gets us .01N/kW=10000µN/kW overall for the whole system (and added mass to the system, but total mass of EMdriven spacecraft doesn't play any role in the CoE issue). 10000µN/kW is not really interesting compared with ion thruster (given contemporary flight ready sources of power...), and would make power generation from apparent CoE breaking (breakeven) impractical (critical velocity>100km/s) , but still possible in principle, and that's obviously a problem with known physics.
Please refer to a setting which is constant velocity constant thrust and no kinetic energy involved
https://forum.nasaspaceflight.com/index.php?topic=39004.msg1461319#msg1461319
It is not a problem of duration of "effect", but of frame invariance of the effect. 1s of thrust at .01µN/kW is already too much not to apparently break CoE if such thrust/power is possible regardless of absolute velocity (relative to what ?). Said otherwise, the apparent problem is with a "frame agnostic" EMdrive : a device that with the same given power will have the same thrust (an accelerometer will record the same acceleration for the driven craft) whether or not it has previously been subject to some arbitrary deltaV by conventional mean. If I can send a .01µN/kW for 30s (as measured in the lab) EMdrive on a conventional rocket (say, a fission fragment rocket) at 200km/s, power it for 30s and still measure .01µN/kW onboard, then I have a CoE issue. I'd have a hard time actually extracting useful energy from that, but that doesn't prevent the problem within known frameworks. Happen to be, sun is orbiting galaxy at about 200km/s. On a 12 hours span, the same experiment (depending on latitude...) would experience a differential of up to 400km/s wrt. its orientation to some galactocentric frame. So in a sense we can say that EMdrives have already (are) tested at such velocities... even while standing almost still on the bench and doing their µm displacement against balances. Can you find a natural frame with lower relative velocities that still makes sense for deep space application ?
BTW, while a "frame agnostic" EMdrive can in principle (>3.33µN/kW) and in practice (approx. >1N/kW) reach break-even and be used as a generator, the same device can be used to "erase" energy, i.e. act as a net sink of power, that apparently (in waste heat) radiates less than spent power. See how ?
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#1514 by Mulletron on 09 Jan, 2016 11:37
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Hey TheTraveller, using your goal seek, can it come up with a TE013 cavity which resonates at the hydrogen line? It doesn't have to be perfectly dead on as long as it's precisely tunable.
https://en.m.wikipedia.org/wiki/Hydrogen_line
https://en.m.wikipedia.org/wiki/Hydrogen_maser
This is down the road stuff that's interesting to think about and related to Rodal's Ammonia maser idea @24ghz. Possibly an alternative to injecting large amounts of rf into a cavity, I'd be interested in having the radiation produced within the cavity itself. Certain excited atoms can produce microwave radiation with extreme frequency stability. Besides hydrogen and ammonia already mentioned, cesium 133 is another https://en.m.wikipedia.org/wiki/Caesium_standard (I actually work on a model of these :-)
Closely related, if anyone is interested in light matter interactions within cavities, this video is kind of long but features some info related to microwaves and copper cavity experiments. It's a really great overview of cavity QED. Between minutes 12 and 19, he discusses the road towards strong coupling in cavity QED. The Q factors discussed in the video are insane compared to any known EmDrive.
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#1515 by Mulletron on 09 Jan, 2016 14:32
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In the above video, he mentions that as they were trying to improve Q, they started with copper, then went to niobium, and then went back to copper (but highly polished) and coated with a thin layer of niobium.
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#1516 by Notsosureofit on 09 Jan, 2016 14:41
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In the above video, he mentions that as they were trying to improve Q, they started with copper, then went to niobium, and then went back to copper (but highly polished) and coated with a thin layer of niobium.
A sputtered layer of niobium ! (We do sputtering) -
#1517 by birchoff on 09 Jan, 2016 16:36
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found a reference to this paper on my Facebook wall
http://arxiv.org/abs/1504.00333
Read through it briefly and it lead me to wonder something. Assuming The author of the paper is correct. We can throw very very strong magnetic fields at space/time and generate artificial gravity fields. Now the interferometer detector outlined in the paper is similar to the one Dr. White proposes in one of his warp field detection papers. With the main difference being that the paper's author uses a precise arrangement of super conducting magnets to phase shift the light, while Dr. White attempts to use a Q-Thruster/EmDrive to do the same thing. Now if I use what very little non peer reviewed information that Star-Drive posted in a previous thread of proof, that an EmDrive can generate an artificial gravity field, to support the assumption that Dr. White's proposal is also correct. The thing that strikes me as interesting about both proposed experiments is that the Paper's Author is bending Space/Time with a static electro-magnetic field. While Dr. White would seem to be doing the same thing with a dynamic electro-magnetic field. While I don't believe the EW EmDrive experiment emits EM Fields as strong as the ones that would be generated in the experiment proposed by the author's paper. I cant help but wonder if the reason the EW EmDrive may not need to generate such strong fields to create the same effect may be because the dynamic EM Field's in the EmDrive are interacting with Space/Time at its resonant frequency, thereby leading to a magnification of the effect. -
#1518 by Eric Hedman on 09 Jan, 2016 16:46
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#1519 by Rodal on 09 Jan, 2016 17:51
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In the above video, he mentions that as they were trying to improve Q, they started with copper, then went to niobium, and then went back to copper (but highly polished) and coated with a thin layer of niobium.
A sputtered layer of niobium ! (We do sputtering)
A clarification for the general audience and DIY's, concerning the sensitivity of the electrical conductivity (and hence the quality of resonance Q) to the temperature range :
QUESTION: What is the explanation for a higher quality of resonance (Q) with Niobium than with Copper ?
ANSWER: It has to do with the superconducting temperature range, but not at room temperature. At ambient conditions, copper is 9 times better than Niobium concerning electrical conductivity, and therefore concerning Quality of Resonance (Q).
The superconducting temperature of Niobium is 9.3 K (that's significantly below the boiling point at room pressure of Liquid Nitrogen: 77 K, and below the critical point of Liquid Hydrogen: 33 K)
Copper is not a superconductor. The best conductors at room temperature (gold, silver, and copper) do not become superconducting at all. They have the smallest lattice vibrations, therefore the electron phonon interaction is weak in copper, silver or gold so that Coulomb effects win and prevent superconductivity.
See the commonly quoted electrical resistivity and conductivities of these materials at ambient conditions:
________________
According to
1) https://en.wikipedia.org/wiki/Niobium
Niobium Electrical resistivity = 1.52 ×10^(−7) Ω•m ( at 0 °C)
therefore
Niobium Electrical conductivity = 6.579 *10^6 S/m
2) http://www.webelements.com/niobium/physics.html
Niobium Electrical resistivity = 1.52 ×10^(−7) Ω•m
therefore
Niobium Electrical conductivity = 6.579 *10^6 S/m
3) http://www.allmeasures.com/Formulae/static/materials/140/electrical_resistivity.htm
Niobium Electrical resistivity = 1.44 ×10^(−7) Ω•m
therefore
Niobium Electrical conductivity = 6.944 *10^6 S/m
________________
4) http://eddy-current.com/conductivity-of-metals-sorted-by-resistivity/
Pure Copper Electrical resistivity = 1.664 ×10^(−8) Ω•m
therefore
Pure Copper Electrical conductivity = 6.009 *10^7 S/m
_________________
According to the above quoted data, Pure Copper has an Electrical Conductivity that is 9 times greater than Niobium at ambient temperatures, therefore everything else being equal, pure copper should give a Q 9 times better than Niobium, at ambient conditions (for polished and non-corroded copper)
_________________
It is at superconducting temperatures that Niobium's electrical conductivity is superior to pure copper.
See:
http://arxiv.org/ftp/cond-mat/papers/0308/0308266.pdf
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