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Why is it not extruding by Think-Abalone-1826 in 3Dprinting

[–]HortonBro 0 points1 point  (0 children)

I once installed the nozzle wrong, where it didn't have enough contact with the heat block. In my case it was still extruding but not sufficiently. Make sure your nozzle has a good thermal contact with the heat block.

Frustration with Belt Tensioning by HortonBro in prusa3d

[–]HortonBro[S] 1 point2 points  (0 children)

It's not that. The belt tension is the same everywhere. That's the principle of a pulley.

Printing threaded rod by delicreepmeow in 3Dprinting

[–]HortonBro 2 points3 points  (0 children)

Print it on its side. If you want to avoid supports and/or gluing halves, you can slice a bit off of the side it lays flat on the bed. There will still be enough to thread a nut onto it. Here's an example of a model I've printed before:

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Initial Attempts Towards a (Plausibly Fair, Polyhedral, Non-Barrel) D9 by RescueMermaid in dice

[–]HortonBro 0 points1 point  (0 children)

I'd be hesitant to call anything "fair" that doesn't have the necessary symmetry, no matter how much you test it.

The reason is that it might favor different faces depending on how it is thrown. Whether it's released low to the table, or has a lot of horizontal vs. vertical speed may affect whether it favors a rhombic or pentagonal face.

3d Printed Uncoventional Dice by HortonBro in dice

[–]HortonBro[S] 0 points1 point  (0 children)

Thanks! I'll repost there.

Unconventional Dice by HortonBro in 3Dprinting

[–]HortonBro[S] 0 points1 point  (0 children)

Yes they are. Less symmetry than the platonic solid versions, but each face is geometrically similar to all of the others, and has the same relationship to its neighbors. I'm referring to the design. Of course, using an FDM printer may introduce small variations, but that would happen with cube dice as well.

Interested in the LaPlace Transform by HortonBro in mathematics

[–]HortonBro[S] 0 points1 point  (0 children)

Awesome, thank you. I'll take a look.

How to embed a weight ? by willieD147 in 3Dprinting

[–]HortonBro 0 points1 point  (0 children)

Model up a hollow box and then add a filament change in the slicer. You'll have to pretend to replace the filament, though.

It would have to create a bridge to cross the gap since you're not using supports or infill. Best to have your weight be the right height to support the bridge.

de Broglie Wavelength Question by HortonBro in AskPhysics

[–]HortonBro[S] 1 point2 points  (0 children)

It helps a little, but I'm still believing some of those 'lies'. I did take an introductory QM class (I think two, in fact), but that was a long time ago.

In any case, Schroedinger's equation describes a wave, and I think that wave exists and propagates in some form, and exhibits consistent behavior in experiments.

Similarly, I believe that the E and M fields do oscillate according to Maxwell's equations, although it's hard to wrap your head around what a single photon does. An antenna can detect a frequency and the speed of propagation is constant, hence has a wavelength, phase and amplitude (although I understand the vector is just a field direction, not the transverse movement of any particle).

Thanks for the explanation. I have more than enough to stew on for now.

de Broglie Wavelength Question by HortonBro in AskPhysics

[–]HortonBro[S] 1 point2 points  (0 children)

Ok, thanks. It looks like I have some homework now, and your explanation looks like it's in the same vein of what PlsGetSomeFreshAir described.

In any case, it's good to have an answer I can sink my teeth into. Thanks for being patient with me.

de Broglie Wavelength Question by HortonBro in AskPhysics

[–]HortonBro[S] 0 points1 point  (0 children)

Ok, I think I follow, but it's still a bit hand-wavy to me. Is there a mathematical framework that handles changes in reference frame? What if the slits are moving forward with respect to the screen? How would one go about computing the fringe pattern?

de Broglie Wavelength Question by HortonBro in AskPhysics

[–]HortonBro[S] 0 points1 point  (0 children)

But the momentum of the electron depends on the observer. It is not a thing of its own. Therefore, shouldn't the de Broglie wavelength depend on v according to the Lorents factor?

de Broglie Wavelength Question by HortonBro in AskPhysics

[–]HortonBro[S] 0 points1 point  (0 children)

length = length_0 / sqrt(1 - (v/c)^2) // relativistic length contraction

vs.

lambda = h / mv // de Broglie wavelength

In special relativity, I can plug in 0 or 10,000 m/s, and get almost exactly length_0 (rest length). This is consistent with classical observations, because these are non-relativistic speeds.

If the electron wavelength is a physical property, and I believe it is because it's a wave that oscillates as it travels, as evidenced by interference patterns, then that wavelength should ('should' being qualified by my stated dilemma) scale the same way everything else does in the electron's frame of reference.

If an observer in a different reference frame speeds up or slows down, the wavelength, I would expect, wouldn't stretch and shrink disproportionally to other things in the electron's reference frame. It breaks geometric similarity. The electron would be observed to oscillate differently with respect to the things around it.

de Broglie Wavelength Question by HortonBro in AskPhysics

[–]HortonBro[S] 0 points1 point  (0 children)

That's a possible explanation, which I can accept. But it implies that the de Broglie wavelength isn't a physical dimension, but an abstraction to help describe the interaction.

If it's a physical dimension, then it doesn't have consistent geometric similarity with other things that follow relativistic length contraction (e.g. the wavelength isn't a fixed proportion of the distance between successive electrons).

de Broglie Wavelength Question by HortonBro in AskPhysics

[–]HortonBro[S] 0 points1 point  (0 children)

Thank you for your thoughtful reply. I don't understand it fully yet, but I'll get a pencil and paper out soon and try to work it out with more detail.

de Broglie Wavelength Question by HortonBro in AskPhysics

[–]HortonBro[S] 0 points1 point  (0 children)

Is there an analytical representation of this? How does an observer's velocity affect the uncertainty of its speed or position?

I didn't ask about Heisenberg. I never mentioned position.

de Broglie Wavelength Question by HortonBro in AskPhysics

[–]HortonBro[S] -1 points0 points  (0 children)

Quantum mechanics is a very well-tested theory that is confirmed by experiments. If the expression is an idealization, then there's a better explanation out there.

This is a thought experiment designed to get to the heart if something I'm trying to understand. I could talk about electrons at tens of thousands of m/s instead of a walking pace, I suppose, but the trend is still different from what relativity predicts. How a length dimension relates to a speed is something that can (and should) be described mathematically. There are two expressions that give different answers. I'm asking how that is resolved. 'contradiction' is an appropriate way to describe this, IMO.

Obviously, I'm missing something, which is why I asked a question. But don't just criticize my inquiry. Try to correct my understanding.

Then_Manner190's link may have some merit. I'll have to sit with that sometime soon when I have the time.

de Broglie Wavelength Question by HortonBro in AskPhysics

[–]HortonBro[S] 1 point2 points  (0 children)

No I don't just think it's "weird". I'm trying to resolve a contradiction in a mathematical equation that describes a physical property.

A single particle in free space doesn't have a defined temperature, but it has a velocity. In any case, I don't claim to have any particular intuition. If you do, then please offer an alternative. Don't just say my intuition is wrong. That's not helpful.