I understood that.
Just.
VCU Torque test results
- Thread starter The Mad Hat Man
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Just.
GrumpyGel
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My son it tidying up his thesis for his physics Masters. He has to submit it in a few days.
I'm giving it a proof read. Its titled "Spectroscopy, crystal-field modelling, and transition intensity modelling of the trigonal oxygen site in Er3+ and Eu3+ doped CaF2".
I understand fook all, but I have found a "there" that should be "their"! I think the 2nd comma in the title is dodgy to.
GrumpyGel
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Just googled it...
The comma before “and” (or comma before “or”) at the end of a list is optional. It's referred to as an Oxford comma or serial comma. Most academic style guides recommend adding it (“salt, pepper, and paprika”). But it's also not a grammatical error to write a list without it (“salt, pepper and paprika”).
So as it's academic, it looks like it should be there. Even though its wrong - fecking academics can't even get a comma right!
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Oxford or not ?
I just googled ‘trigonal oxygen site’.
I’m now going back to try and work out this instead…
T = μ x N x [Some constant] = Weight x Lever Arm
GrumpyGel
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He's studying at 'UC' but we'll assume this is an 'Oxford' comma.
GrumpyGel
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Reading through the thesis, evidently Einstein described some of what it is studying as "spooky". So I'd recommend it would probably be more rewarding to study the interactions between hops and barley in a beerI just googled ‘trigonal oxygen site’.
I’m now going back to try and work out this instead…
T = μ x N x [Some constant] = Weight x Lever Arm
Ahh… finally something I can grasp!Reading through the thesis, evidently Einstein described some of what it is studying as "spooky". So I'd recommend it would probably be more rewarding to study the interactions between hops and barley in a beer
Bife
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You'd have to plot 1/time as that equation has N which is revs
That equation makes sense, as you increase weight &/or lever arm, the speed of rotation (N) increases and so the time to do 1/4 of a revolution decreases.
The equation also tells us that 1/time should vary linearly with length &/or weight
But the equation assumes quite a lot of things
Bife
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Not my area, but I would take the comma out as then its clearer that all three methods all apply to the trigonal oxygen site etc and not just transition intensity modelling. Whatever the **** they are
However, Oxford commas are always a bit of a moot point
If I were him I would leave it in and see what the examiner says - its an easy bait and its good to give the examiner something easy to change in your corrections
If it is spooky then this is a great book:
How to Teach Quantum Physics to Your Dog - Chad Orzel: 9781851687794 - AbeBooks
How to Teach Quantum Physics to Your Dog by Chad Orzel - ISBN 10: 1851687793 - ISBN 13: 9781851687794 - Oneworld Publications - 2010 - Softcover
www.abebooks.com
Disclaimer - I am a Fookin' Academic (but also a mechanic's son) - see my signature
I've probly got it all arse about tit, anyway
Hippo
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We're not calibrating. The One Wheel Up Test OWUT is designed as a diy comparison. Compare your test time to other's. Its a way of knowing if yer vcu needs replaced. Post 246 below.Hi!
Has anyone tried tests to see how the time varies with weight and lever arm length?
From this it seems that Revs/min is simply proportional to torque (weight x lever arm)
View attachment 320037
I know its not the same geometry, but its an 'engineering' equivalent system and everyone's VCU is the same dimensions internally (I pressume), so in the equation
View attachment 320036
our equivalents of L, D & h are constant so we end up with:
T = μ x N x [Some constant] = Weight x Lever Arm
So, if someone did the test with the same VCU then since the viscosity is always the same (assuming the rate effects on viscosity are negligible given the relatively small differences in speed due to different lever arms and weights we would be talking about) then if you plotted time verses lever arm or weight you would get straight lines
Even if the plots of diff weights & levers wasn't exactly linear you could use the plots as 'calibration plots'
Given the variability in the times I have seen between various repetition of the test that you get anyway, any errors due to the assumptions in my approach wouldn't be significant anyway
If that was the case you could convert from times with different lever arms &/or weights
I think
Of course, the best way is if everyone just uses the 'ASTM standard FL1' of 5kg and 1.5 m ' or whatever, but I am just curious
PS I cant do the test myself as my VCU takes forever as it was fried in the PT sun by mistake - DOH! - and I am still waiting for a local guy to get mine refurbished
VCU Torque test results
stolen from Aulro... Testing is accomplished by keeping the housing stationery and having the hub rotate with a constant speed of 75 rpm. Temperature is being measured by means of a thermo coupling on the outside of the housing. Torque transfer in Nm vs. temperature (C) at a speed difference...
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GrumpyGel
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Like what we know it means, which we don't
Alibro
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Last edited:
Bife
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ThanksWe're not calibrating. The One Wheel Up Test OWUT is designed as a diy comparison. Compare your test time to other's. Its a way of knowing if yer vcu needs replaced. Post 246 below.
VCU Torque test results
stolen from Aulro... Testing is accomplished by keeping the housing stationery and having the hub rotate with a constant speed of 75 rpm. Temperature is being measured by means of a thermo coupling on the outside of the housing. Torque transfer in Nm vs. temperature (C) at a speed difference...
I completely understand just using this as a comparative test - I was just curious
I did my own spreadsheet: analysis from the data from around your link
If speed was simply proportional to the torque the power of x in the below would have been -1, but its not.
Interestingly (for a geek like me anyway) Hippo's, Chris2000's and Seraphin's values all lie along the same trend line
BUT, MrBlockPaving's are much quicker
He did say he did it at 6 degrees C though
I thought, wait a minute but viscosity usually increases with lower temp so his times should be higher
Then I realised - the whole point of the VCU is that it has a special fluid in that has a viscosity that increases with temp (that's how it works)
So that makes absolute sense
What I think is interesting is that not only are times are obviously strongly linked to test temp (I would probably get long time values on a hot Portugal summer 40 C day) but also that the way the times vary with weight also change, so you cant simply assume a constant relationship between time and weight or length - this effect is confounded with temperature - the effects of two parameters interact - the strength of the effect of varying the weight depends on the temperature.
So, in a nutshell, I would do the test with a standard weight and length bar as designated by Senhor Lord Hippo (what is that by the way?) so that everyone's results are comparable
I would also make sure that the bar is the same weight in each case, or even make sure that the weight of the bar plus the hanging weight was a standard weight
I would also at least note the ambient temperature and try to ensure it was pretty close to room temperature if at all possible
Again, all the above in the spirit of my thoughts, I could well be completely wrong - but I enjoy finding things out and having theories shot down is part of that
Top line is Hippo & Chris2000 & Seraphin's data (top equation is Hippos only, Right equation is all 3 together)
Bottom line is MRBlockPavings data at 6 degrees C
R squared is just how well the line fits the data - extremely well here as its almost a perfect 1.0 (simplifying a bit)
PS Maths wont hurt you, dont be scared
Last edited:
GrumpyGel
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That's way above my pay gradeto or too?
Since we're being pedantic anyway.
Thanks
I completely understand just using this as a comparative test - I was just curious
I did my own spreadsheet: analysis from the data from around your link
If speed was simply proportional to the torque the power of x in the below would have been -1, but its not.
Interestingly (for a geek like me anyway) Hippo's, Chris2000's and Seraphin's values all lie along the same trend line
BUT, MrBlockPaving's are much quicker
He did say he did it at 6 degrees C though
I thought, wait a minute but viscosity usually increases with lower temp so his times should be higher
Then I realised - the whole point of the VCU is that it has a special fluid in that has a viscosity that increases with temp (that's how it works)
So that makes absolute sense
What I think is interesting is that not only are times are obviously strongly linked to test temp (I would probably get long time values on a hot Portugal summer 40 C day) but also that the way the times vary with weight also change, so you cant simply assume a constant relationship between time and weight or length - this effect is confounded with temperature - the effects of two parameters interact - the strength of the effect of varying the weight depends on the temperature.
So, in a nutshell, I would do the test with a standard weight and length bar as designated by Senhor Lord Hippo (what is that by the way?) so that everyone's results are comparable
I would also make sure that the bar is the same weight in each case, or even make sure that the weight of the bar plus the hanging weight was a standard weight
I would also at least note the ambient temperature and try to ensure it was pretty close to room temperature if at all possible
Again, all the above in the spirit of my thoughts, I could well be completely wrong - but I enjoy finding things out and having theories shot down is part of that
Top line is Hippo & Chris2000 & Seraphin's data (top equation is Hippos only, Right equation is all 3 together)
Bottom line is MRBlockPavings data at 6 degrees C
R squared is just how well the line fits the data - extremely well here as its almost a perfect 1.0 (simplifying a bit)
View attachment 320086
PS Maths wont hurt you, dont be scared
As an associate professor at UCL, I too read the second comma as being unnecessary
FWIW lol
Alibro
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Does that mean we have to call you Prof Rob from now on?As an associate professor at UCL, I too read the second comma as being unnecessary
FWIW lol
