PSN-L Message - Subject: Re: diamagnetic levitation seismometer possibility

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

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

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