PSN-L Email List Message
Subject: Re: diamagnetic levitation seismometer possibility
From: Charles R Patton charles.r.patton@........
Date: Tue, 10 Jul 2012 20:48:57 -0700
Well, one way to get around this problem would be to use an AC current
to modulate the permanent magnets by an amount bigger than the
valley/crest amplitude.
Chas.
On 7/10/2012 8:24 PM, meredith lamb wrote:
> Charles and all,
>
> PG comes in a range of impurity levels. The "worst" seems to
> range roughly up to ~ 30 parts per million. The average use PG
> seems to vary roughly around 12 to 9 parts per million; I suspect this
> is the usual material ~ we, use or commonly obtain. Lab grade
> PG may range around 6 to 8 ppm. Some "super" pure PG
> (usually used in government nuclear instrumentation), may have
> around 1 to 3 parts per million. These are my "memory"
> estimates...which could be off now....or, manufacturing process's
> could have improved since.
>
> Years back I built a levitation device that consisted of a large
> ring neodymium magnet, and ~ forced a smaller neodymium
> magnet in the center (opposing fields). This was a replica
> of one David Lamb built. With, the right size of round or
> even square PG (that levitates); one can approximate the
> locations of impurities, simply by bringing a much smaller
> magnet near the levitating PG. The PG will rotate and
> settle closest to the small hand held magnet where the
> magnetic impurity exists, and/or for various ~ spots therein.
> All this demonstrates is the existence of the Minuit impurity's and
> in itself it's preference for the PG seeking, say, the greatest
> magnetic field at those locations.
>
> In my experience, with any given horizontal (directional)
> magnet setup and using, say, a 5/8" square of PG; the
> PG will "prefer" ~ several locations along it's path. With
> a gentle slow finger push, the PG will speed up, slow down
> as it crosses these (~ broad) area magnetic peaks and valleys.
> In other words one can adjust the leveling for whatever location
> works best or is more convenient, or, stable, or smoother
> for operation. One could, ascribe such erratic movement
> to variations in the magnetic fields and/or impurities in
> the PG, or other (?) possibilities. Yes; the faster the PG
> moves, the less obvious these peaks and valleys are seen.
>
> Meredith
>
> On Tue, Jul 10, 2012 at 6:40 PM, Charles R Patton
> > wrote:
>
> On 7/10/2012 7:50 AM, Thomas Dick wrote:
>> On 7/10/2012 7:51 AM, chrisatupw@.......
>> wrote:
>>> From: Charles R Patton charles.r.patton@........
>>>
>>> Subject: Re: diamagnetic levitation seismometer possibility
>>> Interesting observations about the possibility of diamagnetic
>>> roughness. This brings up two observations:
>>> 1) By the current theories of magnetic flux lines as I
>>> understand them, there is no possibility for them to exhibit
>>> "kinks or roughness" at the scales and method of field
>>> generation we're discussing.
>>> Hi Charles,
>>> That is correct as I understand it. Flux lines in free space are
>>> often curved, but never kinky!
>>>
>>> 2) So that leaves two possibilities in my mind:
>>> a) The magnetic field is undergoing slight changes in field
>>> strength with the actual counterpressure of the carbon being
>>> levitated. Hard to imagine with the relative strengths of the
>>> permanent magnets -- but still a possibility.
>>> There is no reason to suppose that the tiny reaction is in any
>>> way 'rough' or inelastic.
>>>
>>> b) The carbon diamagnetic properties exhibit a domain
>>> phenomenon in a similar vein to the ferromagnetic properties of
>>> iron.
>>> The diamagnetic materials don't form domains. The domains in
>>> some ferrous materials are a property of the close coupled
>>> interaction in that particular crystal stucture between the iron
>>> atoms. But you DO get alloys containing a high proportion of
>>> iron which are NOT ferro-magnetic !! eg the Austenitic Stainless
>>> Steels.
>>> While the field strength at the magnet's surface is likely to
>>> vary along the length, the levitation is maybe 1/2 to 1 mm, but
>>> small quakes are measured in 10s of nano metres, maybe 1/10,000
>>> of this.
>>> In a more blue sky way of reasoning, project the following thoughts:
>>> 1) Dr. Randall Peters has brought to this list the interesting
>>> concepts of mesoscale damping. Part of what I take away from
>>> that concept is that as we burrow down in dimension, the concept
>>> of an amorphous solid with smooth mathematically described
>>> properties breaks down. Just as ferrous magnetics were thought
>>> to be smooth, the discovery of Barkhausen noise was discovered
>>> early on to be the individual magnetic domains switching.
>>> Diamagnetic properties come from electron properties of masses
>>> of atoms just as the ferrous magnetic properties do. So, atoms
>>> can move within a "solid". The most stable solids are
>>> crystalline in nature, where the atoms are locked in both space
>>> and orientation. The big question, "Would a crystalline
>>> diamagnetic solid exhibit this magnetIc "roughness", perhaps
>>> equivalent to the Barkhausen noise? The experiment to perform
>>> here is to use a Barkhausen test setup, but substitute carbon
>>> for iron.
>>>
>>> Charles R. Patton
>>>
>>> On 7/9/2012 9:34 AM, chrisatupw@.......
>>> wrote:
>>> From: Bob McClure bobmcclure90@.........
>>>
>>> Sent: Mon, 9 Jul 2012 15:02
>>> Subject: Re: diamagnetic levitation seismometer possibility
>>>> I, too, have carried out diamagnetic levitation experiments
>>>> similar to those by Meredith Lamb. Although the large amplitude
>>>> motion looks smooth and frictionless, what I concluded for very
>>>> small amplitudes, such is not the case. The supporting magnetic
>>>> field has small-scale roughness, and the levitated graphite
>>>> tends to hung up in the hills and valleys of the resulting force.
>>>>
>>>> I don't understand this. I would only expect 'field roughness'
>>>> to show up for linear motions comparable to the levitation
>>>> height, of 1/2 to 1 mm, NOT for tiny movements of ~100 nano
>>>> metres.
>>>> One problem that I had with levitating graphite was due to it's
>>>> propensity to pick up lint, hairs and dust. These can and do
>>>> effect a very light slider. Another problem is the extremely
>>>> high field gradients at the edges of the magnets picks up
>>>> magnetic and paramagnetic dust only too easily. I clean magnets
>>>> using a roll of PVC tape - you stick it onto the surface and
>>>> then peel it of with the rubbish attached.
>>>> Regards,
>>>> Chris Chapman
>>>
>>>
>> Chris & all ...
>>
>> All of you seem locked in on the material being the problem ...
>> and you may be correct. But what if, the "change" you are
>> "seeing" and blaming on the field roughness is being induced by
>> earth's magnetic field or from other radiations from space. I
>> suggest shielding could be an issue. Some of you might remember a
>> seismic unit I created years ago using a large horseshoe shaped
>> magnet dampened with oil. That setup was affected by the 200 watt
>> 10 meter amateur radio repeater I was operating at the time.
>>
> After more thought, there is a material related "roughness" that
> comes to mind. For a moment follow me with a thought experiment.
> You have a stick that smoothly alternates in diameter along it
> length and whose density is less than that of water. You push the
> stick lengthwise into the water while plotting the pressure it
> takes. This plot will show a pressure variation due to the
> diameter variation. This immersion is very similar to the carbon
> in a magnetic field. We know that the preparation method is
> important to making diamagnetic carbon, and therefore I don't
> think it's a great leap of imagination to believe that is not
> entirely diamagnetically uniform at the macroscopic level. Now
> for the leap in this analogue. Back to the stick. Instead of a
> smoothly varying profile, imagine a sawtooth, perhaps even a bit
> re-entrant. As it is pushed in the water the pressure required
> will have steps -- the "roughness" characteristic. Furthermore if
> the ridges form actual water holding ridges (like a water fountain
> made from bowls) then this will even have a hysteresis
> characteristic. I argue that inclusions of low or
> non-diamagnetic particles/portions in the carbon will lead to a
> roughness of the levitating force as the carbon moves up and down
> in the levitating field.
> Regards,
> Charles R. Patton
>
>
Well, one way to get around this
problem would be to use an AC current to modulate the permanent
magnets by an amount bigger than the valley/crest amplitude.
Chas.
On 7/10/2012 8:24 PM, meredith lamb wrote:
Charles and all,
PG comes in a range of impurity levels. The "worst" seems to
range roughly up to ~ 30 parts per million. The average use
PG
seems to vary roughly around 12 to 9 parts per million; I
suspect this
is the usual material ~ we, use or commonly obtain. Lab
grade
PG may range around 6 to 8 ppm. Some "super" pure PG
(usually used in government nuclear instrumentation), may
have
around 1 to 3 parts per million. These are my "memory"
estimates...which could be off now....or, manufacturing
process's
could have improved since.
Years back I built a levitation device that consisted of a
large
ring neodymium magnet, and ~ forced a smaller neodymium
magnet in the center (opposing fields). This was a replica
of one David Lamb built. With, the right size of round or
even square PG (that levitates); one can approximate the
locations of impurities, simply by bringing a much smaller
magnet near the levitating PG. The PG will rotate and
settle closest to the small hand held magnet where the
magnetic impurity exists, and/or for various ~ spots therein.
All this demonstrates is the existence of the
Minuit impurity's and
in itself it's preference for the PG seeking, say, the
greatest
magnetic field at those locations.
In my experience, with any given horizontal (directional)
magnet setup and using, say, a 5/8" square of PG; the
PG will "prefer" ~ several locations along it's path. With
a gentle slow finger push, the PG will speed up, slow down
as it crosses these (~ broad) area magnetic peaks and
valleys.
In other words one can adjust the leveling for whatever
location
works best or is more convenient, or, stable, or smoother
for operation. One could, ascribe such erratic movement
to variations in the magnetic fields and/or impurities in
the PG, or other (?) possibilities. Yes; the faster the PG
moves, the less obvious these peaks and valleys are seen.
Meredith
On Tue, Jul 10, 2012 at 6:40 PM,
Charles R Patton
<charles.r.patton@........>
wrote:
On 7/10/2012 7:50 AM, Thomas Dick wrote:
Interesting
observations about the
possibility of
diamagnetic roughness.
This brings up two
observations:
1) By the current
theories of magnetic
flux lines as I
understand them, there
is no possibility for
them to exhibit "kinks
or roughness" at the
scales and method of
field generation we're
discussing.
Hi
Charles,
That is correct as I
understand it. Flux
lines in free space
are often curved, but
never kinky!
2) So that leaves two
possibilities in my
mind:
a) The magnetic
field is undergoing
slight changes in field
strength with the actual
counterpressure of the
carbon being levitated.
Hard to imagine with the
relative strengths of
the permanent magnets --
but still a
possibility.
There
is no reason to
suppose that the tiny
reaction is in any way
'rough' or inelastic.
b) The carbon
diamagnetic properties
exhibit a domain
phenomenon in a similar
vein to the
ferromagnetic properties
of iron.
The
diamagnetic materials
don't form domains.
The domains in
some ferrous materials
are a property of the
close coupled
interaction in that
particular crystal
stucture between the
iron atoms. But you DO
get alloys containing
a high proportion of
iron which are NOT
ferro-magnetic !! eg
the Austenitic
Stainless Steels.
While the field
strength at the
magnet's surface is
likely to vary along
the length, the
levitation is maybe
1/2 to 1 mm, but small
quakes are measured in
10s of nano metres,
maybe 1/10,000 of
this.
In a more blue sky
way of reasoning,
project the following
thoughts:
1) Dr. Randall Peters
has brought to this list
the interesting concepts
of mesoscale damping.
Part of what I take away
from that concept is
that as we burrow down
in dimension, the
concept of an amorphous
solid with smooth
mathematically described
properties breaks down.
Just as ferrous
magnetics were thought
to be smooth, the
discovery of Barkhausen
noise was discovered
early on to be the
individual magnetic
domains switching.
Diamagnetic properties
come from electron
properties of masses of
atoms just as the
ferrous magnetic
properties do. So,
atoms can move within a
"solid". The most
stable solids are
crystalline in nature,
where the atoms are
locked in both space and
orientation. The big
question, "Would a
crystalline diamagnetic
solid exhibit this
magnetIc "roughness",
perhaps equivalent to
the Barkhausen noise?
The experiment to
perform here is to use a
Barkhausen test setup,
but substitute carbon
for iron.
Charles R. Patton
On 7/9/2012 9:34 AM,
chrisatupw@.......
wrote:
From: Bob
McClure bobmcclure90@.........
Sent: Mon, 9 Jul 2012
15:02
Subject: Re:
diamagnetic levitation
seismometer
possibility
I, too,
have carried
out
diamagnetic
levitation
experiments
similar to
those by
Meredith Lamb.
Although the
large
amplitude
motion looks
smooth and
frictionless,
what I
concluded for
very small
amplitudes,
such is not
the case. The
supporting
magnetic field
has
small-scale
roughness, and
the levitated
graphite tends
to hung up in
the hills and
valleys of the
resulting
force.
I
don't
understand
this. I would
only expect
'field
roughness' to
show up for
linear motions
comparable to
the levitation
height, of 1/2
to 1 mm, NOT
for tiny
movements of
~100 nano
metres.
One problem
that I had
with
levitating
graphite was
due to it's
propensity to
pick up lint,
hairs and
dust. These
can and do
effect a very
light
slider. Another
problem is the
extremely high
field
gradients at
the edges of
the magnets
picks up
magnetic and
paramagnetic
dust only too
easily. I
clean magnets
using a roll
of PVC tape -
you stick it
onto the
surface and
then peel it
of with the
rubbish
attached.
Regards,
Chris Chapman
Chris & all ...
All of you seem locked in on the material being the
problem ... and you may be correct. But what if,
the "change" you are "seeing" and blaming on the
field roughness is being induced by earth's
magnetic field or from other radiations from space.
I suggest shielding could be an issue. Some of you
might remember a seismic unit I created years ago
using a large horseshoe shaped magnet dampened with
oil. That setup was affected by the 200 watt 10
meter amateur radio repeater I was operating at the
time.
After more thought, there is a material related
"roughness" that comes to mind. For a moment follow me
with a thought experiment. You have a stick that smoothly
alternates in diameter along it length and whose density
is less than that of water. You push the stick lengthwise
into the water while plotting the pressure it takes.
This plot will show a pressure variation due to the
diameter variation. This immersion is very similar to the
carbon in a magnetic field. We know that the preparation
method is important to making diamagnetic carbon, and
therefore I don't think it's a great leap of imagination
to believe that is not entirely diamagnetically uniform at
the macroscopic level. Now for the leap in this
analogue. Back to the stick. Instead of a smoothly
varying profile, imagine a sawtooth, perhaps even a bit
re-entrant. As it is pushed in the water the pressure
required will have steps -- the "roughness"
characteristic. Furthermore if the ridges form actual
water holding ridges (like a water fountain made from
bowls) then this will even have a hysteresis
characteristic. I argue that inclusions of low or
non-diamagnetic particles/portions in the carbon will lead
to a roughness of the levitating force as the carbon moves
up and down in the levitating field.
Regards,
Charles R. Patton
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