Large Hardon Collider

[Woozie]

Oh yeah, I forgot to add the footnote I was going to put (which is why I have an asterisk after the sentence saying that normal matter are fermions). Technically, normal matter can be fermions or bosons. The constituent particles are all fermions, but if you put two fermions together, their spins will add to an integer (for example, an electron has a spin of plus or minus 1/2. If you have two of them together, their spins add up to 1, 0, or -1. Another example is the nucleus of the Helium 4 atom, which has two protons and two neutrons and is thus a boson). When normal matter is paired in such a way as to form bosons, you can get some weird effects such as superconductivity (which is a result of electrons forming pairs) or superfluids.

[Kaylia]

Holy crap, a physics news that doesnt involve water on Mars, the discovery of another not so Earth-like planet, or the possibility of an imminent discovery of the Higg Bosons. I can't even nitpick the details of the articles (they mentioned they still need to repeat the experiment, and gave the margin of error).

CERN says a neutrino beam fired from a particle accelerator near Geneva to a lab 454 miles (730 kilometers) away in Italy traveled 60 nanoseconds faster than the speed of light. Scientists calculated the margin of error at just 10 nanoseconds, making the difference statistically significant.

While we should wait for the experiment to be repeated, these numbers, if true, are very scary and interesting.

[Not Kuno]

I was wondering why there was no new thread. You're all having the party in here. This is fucking cool.

[Siralin]

I've got a question for the mechanically inclined of the thread (this seems to be the best place to ask it on bg) Would magnets on gear "teeth" work to eliminate friction? Or is this just a stupid idea and I can't see why it wouldn't work? I've been looking into building a clock from scratch for my intro to egr project and that idea popped up. In the few hours that I've put into researching clocks, I haven't been able to find anything on magnets used on the gears themselves. I've seen a few clocks with magnetic escapements, but nothing quite like what I have in mind. Honestly, I'm not even sure if the introduction of magnets would increase or decrease the amount of force necessary to turn the gears. I know there are other ways to make something spin, but I really like the idea of gears. Any ideas?

Edit: Upon further thought...I guess that could help, assuming it actually works, but the main place where friction would matter is at the axis of the gear, correct? Which is why they use jewels I believe...

[Kaylia]

I'm too tired to think straight, but at first glance, I don't think it would work for two reasons

1) Removing the friction on the gear wouldn't change anything since there is no friction in the first place. It's just one thing pushing another

2) If both gears repulse each other, they will be attracting each other the next instance, making the whole thing pointless

The concept however is very similar to alternator where the magnetic field constantly change and acccelerate the rotating object, but with magnet alone, it wouldnt work.


[edit]
The axis need friction as well since its what make the gears rotate. If you mean the friction with a support, then I agree. That's generally where magnet levitation come handy.

[chikalin]

Magnetic levitation was what I was planning on using to get around the axis friction. The way I had planed the gears was to have one magnet on each side of the tooth so that the always repelled each other. I believe there is a slight amount of force lost due to friction in gears, but I cold be wrong. The generally polish the teeth, so I figured if they do that, there must be a reason. Having no contact, but still relaying the movement would also be good because there would be less chance of jams and they wouldn't require any lubrication. I'm just not sure if the added weight of the magnets on the gears will require more force to actually turn it. It seems possible to do it, and I think it will certainly be fun to do, but I doubt it has any practical use or does anything better than other clock. Biggest problem at this point is designing a contact-less escapement.

Fuck, forgot it was on my gf's laptop. sorry mods

[Kaylia]

Like I said last night, having magnets on the teeth wouldn't work. If they alternated between N and S, the force would end up canceling each other and nothing would move. Just draw a picture of the resulting forces, and you will easily see that there is as many going up than down.

Another way to look at it is that you're basically describing a perpetual motion machine. If the magnet you placed repulsed each other constantly, it's would accelerate nonstop without any outside force. Something like this can't exist, and the reason here is that for every possible "boost" you get, you will get another phase where they slow each other down.


What make it worse is that both wheel would also end up repulsing/attracting each other, increasing the overall stress on the system.

I believe there is a slight amount of force lost due to friction in gears, but I cold be wrong.

Again, the energy is wasted where the wheel touch the structure, not where the gears touch each other. If you have WD-40 on you, you're not going to spray it on the teeth, you're going to use on fixed piece that isn't moving and slow down the rotation



And one last thing, in the case of gears, the force is generally perpendicular, and the friction is non existent.

[Siralin]

I'm not expecting perpetual motion or any gain, just contact-less transmission of power. On whether or not gear tooth surfaces require lubrication:

Proper lubrication is important to prevent premature wear of gear tooth surfaces.

Tooth contact is primarily rolling, with sliding occurring during engagement and disengagement.

http://www.cedengineering.com/upload...20Bearings.pdf

Friction between sliding surfaces at the gear tooth contact is usually the major source of power loss in gear transmissions.

http://gltrs.grc.nasa.gov/reports/1996/TM-107279.pdf

I realize the main point at which lubrication is generally required is at the structure, but if there is sliding occurring at engagement and disengagement that must mean that there is friction.

Just to confirm we're on the same page with the gear layout (I don't think we are) here'e an overly simplified, not to scale etc etc diagram.:

Spoiler: show

http://img855.imageshack.us/img855/3448/maggear.png

Also, I know contact-less transmission is possible with permanent magnets. Magnomatics' transmission is much better and much more complicated, but it is possible with permanent magnets. I just don't have the means (or, tbh, the knowledge) to create something like that. Nor would I waste time putting it in a clock...so I have to try and use a more simplified version.

I hope I'm not coming across as dense for arguing this. I promise I'm not arguing it simply because I want my idea to "work". I'm really just not seeing why it wouldn't and I would really like to understand why, if in fact, it doesn't.

[Restrat]

in that picture, the top gear rotates counter clockwise. but at one point, the set of magnets on the left are just as close at the magnets on the right, so the force is pushing it to rotate clockwise. Overall the two would cancel each other out

[Siralin]

in that picture, the top gear rotates counter clockwise. but at one point, the set of magnets on the left are just as close at the magnets on the right, so the force is pushing it to rotate clockwise. Overall the two would cancel each other out

They will be equal distances from each other at one point, but the bottom gear cannot rotate the other way due to the weight driving the bottom gear. (Think weight tied to a string wrapped around the axle) As long as the weight provides enough power to turn the wheel past the point at which they're equally opposing each other, it should work. I had thought about eliminating the magnet on the backside of the tooth, but that would make it possible for the teeth to come in contact when the front sides repel each other.

[Kaylia]

I was under the impression from your post that you wanted to increase the gears efficiency at transferring energy rather than eliminate the wear completely since you were talking about jam and lubrication. If what you want is eliminating wears alone, then yes, it could works, but there is many thing you have to keep in mind.

The wear is generally an extremely long process, and the energy loss due to it is minimal when compared to the total energy you put it in the system. It's still important to consider if you plan to run your machine long enough to see an physical effect on the material, but other that that, the friction between the teeth can be assumed to be zero (unless your material/angle of contact are terrible)


In this case, your system would prevent the wear at the level of the teeth if the magnet are powerful enough to prevent any contact (how powerful they need to be depend of the speed and force involved). However, the idea also come with its flaw like I said before.

What come to mind is the irregular force transfer (sometime require more energy, other time less). In your picture, the magnet would actually push the gear counterclockwise rather than clockwise, so if you wanted to make it spin, you would have to push even harder, and right after, it would be the opposite (magnet would push clockwise) accelerating the whole thing.

This kind of irregularity is often worse for the system as a whole, because it induce vibration and cause more stress in multiple places (including the power supply). It also means you will waste a lot more energy in the end.

Secondly, finding a proper set of magnet isn't going to be easy either. It would not be possible for every size and force, because two magnets can still touch each other.


[edit]
One question that you should ask yourself is for this kind of system, is gear wear a limiting factor? Eliminating wear is pointless if it's something else that break first, especially when doing this will cost you more energy and probably weaken your system as a whole.

[Pirian]

Disappointed that this thread doesn't get the love it use to

[Eliseos]

I think everyone just got really busy Miz is busy with work, Woozie and Kaylia have been/are probably busy with school, and I've graduated and am also super busy at work.

[Woozie]

I'm not a physics major anymore I'm only applying to math PhD programs


.....applied math

People always say "do what you love", but you have to be realistic. If someone loved basketball or music, you wouldn't encourage them to set their goals to be a pro athlete or a rock star. You'd tell them to find a more realistic goal and do basketball on the side in his/her free time. My first internship taught me that I shouldn't have "professor" as my only goal and my second one taught me that I'd be much happier if I didn't get into any experimental science. However, if I want to do physics and not be a professor, I have to do experimental physics iand get a job by joining the dark side (i.e. engineering-related job) instead of computational or applied, and if I want to do math and not be a professor, I have to join the slightly less dark side and do applied math. Professor is my dream job, but since I know better than to have that as my only option, I decided applied math is my best route since experiments are boring (and any decently trained circus monkey can do those jobs as well as a human with a physics PhD can).

I figured applied math can still let me do science as a career since science since that's one of the major things applied mathematicians do. So I can still have a math and science job if I go this route even though it's not ideal, and I guess I can do physics in my free time.

It still makes me sad though. I'd REALLY like to get my PhD in physics. It's been my dream since I was 16 and my life was saved by a physics book (true story. I don't know if I ever told anyone [I probably told Miz] but that's how I originally got into physics. I was hanging out with gangsters and thugs and getting into lots of trouble with the law as a teenager. I eventually attempted suicide and found a physics book in the hospital, which - long story short - eventually led me to stop hanging out with gangsters and getting in trouble, which changed my entire life. It's so depressing now to not go into physics as a career).

By the way, Miz, UNC is now my top school of choice. If I get accepted I'll definitely be living in NC starting August 2012. How far are you from Chapel Hill?

[Woozie]

Also, it's pretty surprising that this thread didn't get more posts around the time the neutrino thing happened. It's probably because we're all skeptical, but let's face it, we're all hoping and wishing deep down inside that it's true.

[Pirian]

The neutrino thing got it's own thread, and that's probably why.

If Miz is still in Charlotte then Chapel Hill is roughly 2 and a half hours away, but isn't he in Texas?

Also, no need to talk to me about going to the dark side. I went from a physics major when this thread started to economics with emphasis in business now lol. A lot for the same reasons as you - not very exciting job prospects. Your education never has to end, though! Especially if you have a well paying job I wouldn't think it would be that tough to transition to being a professor during the course of getting your PhD. I know that my school requires its masters/PhD students to teach X amount of hours as part of their curriculum (go go cheap labor!).

[Eliseos]

I know that my school requires its masters/PhD students to teach X amount of hours as part of their curriculum (go go cheap labor!).

My school was like that too, and the classes that I had to take that had a grad student as my professor pissed me off. Most of the time they were terrible teachers (even though they were brilliant), or incredibly easy so you didn't learn anything. The only department I thought got it right were the EE's. The grad students would teach the labs, and actual professors would teach the class. That way the grad students got experience grading or whatever they need before they teach without really getting in the students' way.

[Woozie]

Hmm, his facebook says he lives in Columbia, NC.

[Kaylia]

I'm still around. Been checking every day for a new posts, but it was quiet lately. We should unban Max to make thing more lively again.

[Cyn]

Chapel Hill is awesome. I think I go out more there than here in Raleigh. Lots of really cute girls too.