This message has nearly 'grown without bounds', and so you may want to go s=
traight to the last three paragraphs (if you have any interest whatsoever).
Brett, I am glad to hear of how you bake the spring to hasten stability=
.. In some of my experiments performed in vacuum it was necessary to bake =
the entire chamber, as is common practice by those who do high vacuum studi=
es. Otherwise, diffusion pumping that follows mechanical pumping will neve=
r allow one to attain the pressures being sought. These real world frustr=
ations, that are well known to members of 'vacuum societies', point vividly=
to the fact that the physics is even more complicated than just defects/di=
slocations in an otherwise perfect material that we envision (erroneously) =
as existing in no other state than that which we call 'solid'. In other wo=
rds, what has been the focus of our discussion (a spring) is also influence=
d at the 'defect' level even by the gases of the atmosphere in which it ope=
rates! (And incidentally, the surface of a solid is the 'quintessential' d=
efect that cannot be avoided, since the 'perfect' solid must be of infinite=
extent.)
If one altogether doubts that gases don't probably always play som=
e role, at least at some level (perhaps insignificant, but how can such a c=
laim be made without experimental proof) consider an experiment involving a=
shape memory alloy that I performed several years ago, which produced the =
article titled "Study of friction at the mesoscale using Nitinol shape memo=
ry alloy" http://arxiv.org/html/physics/0308077
You will see from this work what is indisputable evidence that gases can si=
gnificantly influence mechanical properties in ways that are not commonly k=
nown. The quality factor differences for the oscillations that are themsel=
ves of different Q, according to whether the material is in the martensitic=
phase or the austenitic phase-are responsible for a profound 'declaration'=
about the importance of defects/dislocations to a spring type oscillator. =
And the manner in which significant phase noise was found to be present, a=
long with 'Brownian motion', means that the low-level fluctuations are exce=
edingly complicated and never completely reproducible. I have facetiously =
said to colleagues through the years: "Guess I will have to report my find=
ings in the journal of non-reproducible results". If such a journal actua=
lly exists, no bonafide scientist would go read anything published there, b=
ecause the very 'heart and soul' of science is reproducibility Consequent=
ly, most of my research publications have been 'open access'; and the Googl=
e search engine seems to have become my greatest ally. I was denied promot=
ion years ago in Texas and the dean who sealed that decision wrote in her l=
etter, "I hope Professor Peters will eventually be able to say I told you s=
o"--concerning my studies of the mesodynamics of mechanical systems. Just=
as I was retiring this past spring, one of the most significant publicatio=
ns of my career was about to be published in Physical Review E (highly este=
emed refereed journal that is the antithesis of open access publishing). L=
ess than a year before this, two distinguished French (nonlinear) math/phys=
ics experts had found one of my papers dealing with catastrophes. I had pu=
blished that article only in one place (Mercer physics personal homepage) b=
elieving (based on painful experiences with referees) that it had about a '=
snow ball's chance in hell' of ever getting published 'conventionally'. F=
ollowing the request by my later-to-be co-authors, I performed an experimen=
t that resulted in our article "Prediction of catastrophes-an experimental =
model". As it was coming together I made a claim to colleagues that proved=
to be 'right on target figuratively'-"there's not a referee in hell who wi=
ll dare reject this paper, because of the outstanding reputation of my co-a=
uthors". (You can readily read the abstract of our article by simply typin=
g 'prediction of catastrophes' into Google without the tick marks of a lite=
ral search. You should be able also to easily with Google find the complete=
preliminary article that was open source published on arxiv.) I mention t=
his to you list-serve readers for another reason-which if it should ever pr=
ove to be profound-remains yet (only after a long time, if ever) to be seen=
.. If you will look at the following paper: http://physics.mercer.edu/hpag=
e/accelerometer/accelerometer.html
You will see what is an event that preceded an earthquake. It is of the ty=
pe that I have seen (in a related context, also by Michael Phillips in Aust=
ralia; who calls one type the "Randall effect') quite frequently as tantali=
zing evidence for 'precursors' to earthquakes. At this point in time, anyb=
ody making a claim for the possibility of meaningful 'early warning predict=
ors' of an earthquake (that could save lives) is viewed as either a (i) mys=
tical quack, or an (ii) ignoramus masquerading as a scientist. The basis f=
or such a position is not without justification, since true earthquake pred=
iction is a 'holy grail' type of quest, afflicted with the greatest of sci=
entific challenges. I personally believe, however, that professional seism=
ologists have not been 'asking the right questions' relative to the matter.=
Just like Nobel Laureate Charles Townes has said the same thing about tho=
se who are life science specialists. It is easy to 'fold one's hands' and =
say "the problem will never be solved". Certainly more physics has been b=
rought meaningfully into cutting edge biology of late, and the same is sore=
ly needed in seismology. I have had little success in my efforts to relate=
meaningfully with professional seismologists, which is part of my reason f=
or coming to your amateur world several years ago. One of my 'successes' w=
ith the pro's was nevertheless realized a few years ago with my BSSA publi=
cation titled "Tutorial on gravitational pendulum theory applied to seismic=
sensing of translation and rotation". This article would never have happe=
ned had I not met the great John Lahr, who like myself had a burning passio=
n for science education. And that passion of his 'spilled naturally' into=
your world, which is the place where I first learned of John and his legac=
y. I was greatly pleased to learn how the genesis of his passion was undou=
btedly part of his earliest university degree (B.S. in Physics from Renssel=
aer in 1966).
The way my tutorial materialized is an example of how the butterfly =
effect of Ed Lorenz suggests meaningful extrapolation beyond his original s=
tatement ("Can a butterfly flap its wings in Brazil and cause a tornado in =
Texas", article presented in the early '60's at a Washington D.C. meteorolo=
gy conference-about his serendipitous discovery of the 'sensitive dependenc=
e on initial conditions that is the foundational part of chaos). In the br=
oader social sense, I see it (involving systems even more complex than atmo=
spheric convection) to describe how "little events of life can unexpectedly=
take on unforeseeable monumental proportions". Early after my use of the =
first fully differential capacitive sensors I became enamored with the pend=
ulum, one of the oldest instruments of science. Few people know the full e=
xtent to which the gravitational pendulum in its 'simplest' form has impact=
ed our world. Even the foundation theories of fluid mechanics (Navier-Stok=
es equations) derive from studies of the pendulum that were performed by th=
e legendary George Gabriel Stokes. Those in turn influenced even the world=
of meteorology where Lorenz is considered the father of chaos theory. Sto=
kes famous-to-physicists theorem, that derived from his pendulum studies, d=
escribes the manner in which only small rain droplets in clouds have a smal=
l enough Reynolds number to remain part of the cloud, while under the influ=
ence of the earth's field of gravity type (little g). In his paper generat=
ed in 1850 ("On the effect of the internal friction of fluids on the motio=
n of pendulums") Stokes rightly predicted that his conclusions would have s=
ignificant impact on the world of meteorology.
Another of my experiences involving butterfly effects of social ty=
pe (that involved the sequential outworking of more than just one) 'revolv=
ed' around the article that I wrote for the 10th edition of the McGraw Hill=
Encyclopedia of Science and Technology. My article accompanies one that w=
as written by Lorenz before his death, and another piece written by a physi=
cs theorist who was at Georgia Tech (quantum mechanics expert named Joseph =
Ford. Ford was the theorist who singularly laid the theoretical foundatio=
n for my experimental dissertation work at Oak Ridge National Laboratory in=
the 1960's. And my major professor (Mack Breazeale) who worked with Ford,=
was associated in his research with the one who became my on-site mentor =
at ORNL, named Victor Pare' (now 84 years of age). Because Dr Pare' is an=
expert in material properties, through his training for the PhD at Cornell=
University-I was circumstantially exposed to valuable concepts involving d=
efects that are not well known the way they should be. Who could imagine s=
uch a chain of butterfly effect events, occurring in two widely separated-i=
n-time parts of my life, yet having such synergetic influence on my practic=
e of physics.
By the way, when I was working with single crystalline copper, it w=
as not useable before being work hardened by fast neutrons from the 'swimmi=
ng pool' reactor at the x-10 plant, to pin dislocations. Had our crystals =
not been so expensive, we envisioned a 'party prank' in which we would give=
one of our long (right circular) cylindrically shaped specimens to a 'weak=
est' female present at our party and have her with both hands (easily) bend=
it into a horse-shoe shape. We would then ask the 'strongest' male presen=
t to come up and restore it to its original configuration. Of course there=
would have been great laughter at his futile attempt to correct what would=
have been so easy for the woman. The crystal would have been for her, not=
quite as soft as butter. But for him, though it would not have been stron=
g as steel, it would have been a heck of a lot tougher than anybody other =
than ourselves could ever have imagined. The reason is because of the enta=
nglement of dislocations that would have resulted from the woman's bending-=
dislocations that start at the end surfaces and work their way inwardly to=
interact and result in work hardening.
I say all this, without hopefully boring the majority of list-serve rea=
ders-because I would love to see more of you change your thinking about the=
abiding great value of the 'simple' pendulum. Some of the pro's have alr=
eady begun to change their thinking about the pendulum. Better part of a c=
entury ago they began to divorce themselves in their thinking from it, but =
there is a 'remnant' that is coming back. The California PhD work of Orteg=
o, under the supervision of Berger, Zumberge, and Wielandt speaks to the ma=
tter. (And Brett, I think I saw a webpage of yours that references the wor=
k??) Their state of the art instrument uses optical (interferometric) sens=
ing, but my expectation is that it could just as well have used a capacitiv=
e sensor (yielding a comparable performance level) if it had employed a ful=
ly differential form. Wielandt still refers to R. V. Jones as the 'ultimat=
e authority' when it comes to sensing of seismic inertial mass motion-wheth=
er for purpose of an error signal based on force feedback, or as is done in=
my VolksMeter which uses a 'simple' pendulum that is not influenced by an =
actuator. Just another example of the butterfly effect involves my creatio=
n of the first fully differential capacitive sensor types. My attempt to g=
et a paper published was met with incredible resistance from some ignoramus=
referees. Eventually the editor at Rev. of Sci. Instr. (Tom Braid) sent =
my paper to Jones, who gave it a positive endorsement, saying that if I wer=
e 'first', then I should be so recognized. Jones in his report stated that=
it clearly had twice the sensitivity (of conventional 'differential capaci=
tive' sensors of comparable electrode dimensions) and he 'liked the symmetr=
y', but had 'become too old' to give himself to a math analysis of my devic=
es. With his death in the late '90's the world lost one of the great pione=
ers of science. Jones was even honored in this country for his WWII work t=
hat helped to save England from destruction by the Nazi's and which also fa=
cilitated U.S. contributions to the war effort.
Should you believe that journal referees (and even editors) must be=
so wise and well trained they surely couldn't be sometimes guilty of incom=
petence (even gross form), listen now to one of the most outrageous example=
s of foolishness in the history of science, involving the laser and the wor=
k of Ted Maiman at Hughes Research Laboratories in 1960. My knowledge of=
what happened is another example of 'butterfly effects' taking place in th=
e social events of one's life. I first learned about Maiman's treatment =
'at the hands of' an editor of Physical Review Letters while I was at lunch=
with a famous physicist named Arthur Schawlow. Dr. Schawlow (deceased N=
obel Laureate, who was the brother-in-law of the better known Nobel Laureat=
e Charles Townes, with whom I have also had close fellowship-another exampl=
e of the butterfly effect) told me to 'consider it a compliment' that my ar=
ticle that had been submitted to Physical Review Letters had been rejected.=
On the 50th anniversary of the creation of the first (ruby) laser, Nature=
chose to engage in a celebration of their publications over the preceding =
century. In one of the pieces that honored Maiman, http://www.press.uchic=
ago.edu/Misc/Chicago/284158_townes.html
Townes said of Maiman's paper that was finally published in Nature: "I bel=
ieve it might be considered the most important per word of any of the wonde=
rful papers in Nature over the past century".
I just received an email from a horologist who is quite familiar =
with issues of material limitations-how their desire for a perfect clock w=
ill never be realized, any more than our desire for a perfect seismometer. =
I do believe, however, that the 'simple' pendulum could be configured to=
minimize some of the 'show-stopper' features of defects, as they have all =
too often impacted some instruments. I may be altogether wrong, but at le=
ast I've done a lot of studies that suggest, why not finally find out from =
experimentation, in just what category to place my claims; i.e., good, bad,=
or ugly. In particular, Brett, I would 'sing the hallelujah chorus' if yo=
u and Dave should choose to make the first ever 'force feedback gravitation=
al pendulum' to function as a first of its kind horizontal seismometer/tilt=
meter. Yes, you have been using something also called by many a pendulum, =
but Galileo who studied the first 'true' (gravitational, 'simple') pendulum=
would have recommended that you use a different 'descriptor'; just as I pr=
efer to label the torsion instrument that was used by Cavendish to measure =
the universal constant ('big') G due to Newton, by the word 'balance' rathe=
r than 'pendulum'. The so called torsion 'pendulum' of Cavendish works in =
a radically different way than the gravitational pendulum studied by Galile=
o and Newton. I believe that the gravitational pendulum, operating with ra=
dically different physics than what describes vertical seismometers-might a=
llow for some important developments. The key to earthquake predictability=
, should it ever be possible-I view as involving calculations of frequency =
domain type, using measurements at longer periods than are accessible by th=
e vast majority of instruments. One of the very few instruments that easil=
y operates there (at least without feedback) is the gravitational pendulum,=
as shown not only in my many experiments and a commercial product as well,=
but also in the dissertation of Ortego. His work was encouraged by Wiela=
ndt, who has said (in effect) that it was time for seismologists to stop ig=
noring some of its important capabilities. The gravitational pendulum is n=
ot prone to 'displacement to the rails' (whether mechanical or electronic),=
which was a major factor in the employment of force feedback to begin with=
, for its use in vertical instruments. Nevertheless, force balance operati=
ng with such a pendulum might open new insights, by providing a first ever =
horizontal instrument of that type.
My conclusions are influenced by the following line of thinking. As y=
ou point out, Brett, the sensor does not represent a 'piece de resistance';=
rather the culprit will always be the components that are most subject to =
the large 'load bearing forces' of most instruments. Incidentally there i=
s physics first recognized by the great Richard Feynman (in his article "th=
ere's plenty of room at the bottom" that explains why MEMS seismometers are=
likely never to perform at the level early builders thought were contempla=
ting. I could easily at this time get into a detailed discussion of Browni=
an motion (based in the equipartition theorem with which every physics grad=
student is thoroughly versed) to prove (if my claims concerning defects ha=
ve any measure of truth) that seismometer performance cannot be properly ga=
uged on the basis of the widespread (overly) simplistic calculation of thre=
shold noise determined by atmospheric molecular motion. It is another one =
of those cases like my previous "let us assume a spherical egg'. It is abs=
olutely amazing to me, the tendency (toward which we are all prone) to make=
assumptions for which the 'baby gets thrown out with the wash'.
Consider the following: can we employ an axis in which the mechanic=
al part of the force that supports our inertial mass (the bob) is made sign=
ificantly smaller than what is typical, without at the same time introducin=
g something new by our 'cure' that is worth than the 'disease' (brought on =
by defect 'antibodies'). Chris Chapman has pointed out (rightfully) that w=
e don't want to place any strong magnet anywhere on an instrument other tha=
n where it is guaranteed to be stationary. And though I have not seen here=
extensive discussions of why ferrous materials should also not be part of =
the moving members; I think it is rather obvious we should not use them und=
er most circumstances. But I think the 'Chapman constraint' (which he has=
in times past eloquently described to you folks) can be relaxed for the fo=
llowing. Consider the axis that is pictured in figure 2 of the following p=
aper, titled "Pendulum sensor using an optical mouse" http://arxiv.org/html=
/0904.3070v1
Most of the weight of the pendulum is supported by the magnetic field =
gradient of the rare earth magnet shown. Thus the force of mechanical type=
involving defects at the contact between the ball-point pen(s) and the low=
er magnet surface is small; i.e., the load bearing force is dramatically re=
duced as compared to what one finds with typical roller type bearings in a =
Lehman, or with 'knife edges' of type found in old analytic chemistry type =
balances to measure mass (they were a compound gravitational pendulum). Of=
course it has been well known for years the important requirement for 'edg=
es' --that they be of very hard material, such as agates in the old balance=
s. The experience of the old master builders of such balances should not b=
e summarily ignored as we contemplate the business of defect influence. T=
o measure a mass at a level of a microgram is no small matter. And if you =
tried to do so with a 'soft' material for the 'edges' of your very best oth=
erwise old instrument you would not be successful, because of the defect pr=
operties of those edges. Thus it is important that both parts of the axis=
are hard material-tungsten carbide of the pen point and the alloy type of =
the rare earth. I also am aware of the fact that there could be some adver=
se features of the surface coating of the rare earth magnet; how it might d=
egrade with time (both chemical and mechanical) and thus impact performance=
.. But isn't it worth some tests? Note that not every ball point pen type =
will work in this way. The part that holds the end ball must be ferrous. =
Many of the inexpensive ball point pens that the Brits like Chris call 'bir=
o' I have found to work. Simply place the writing point of the instrument =
(as purchased) up against a powerful magnet and find out if it will 'stick'=
there. I discovered this quite by accident several years ago while teachi=
ng an undergraduate physics laboratory. With a little free time away from =
the usual student assistance that was needed, I casually 'tested the streng=
th' of a small rare earth magnet by placing it on the upper frame of one of=
the steel doors to the room. Finding it quite hard to then pull away the =
frame, I wondered two things: (i) would it attract my ball point pen?, and=
(ii) if so, just how strong would the attraction be? I was astonished at =
how much weight could be supported by this means, and additionally by what =
resulted after the pen was left swinging. The Q of the free decay of that =
single-point conical pendulum was so great that it was still moving by a vi=
sually perceptible amount many minutes after I had gone back to help my stu=
dents. Some of that motion that I later saw was probably due to air curren=
t disturbances; however, subsequent study has shown that it has the very pr=
operties that I'm encouraging you to explore and hopefully exploit.
So Chris, what about your thoughts on this setup? Can it avoid a '=
show-stopper' consequence of unavoidable environmental field changes? If t=
he ferrous holder of the tungsten carbide of the pen points (required for t=
he force of attraction) were at a place of great motion, then the answer i=
s probably no. But consider its placement that yields very small oscillato=
ry motion, and the realm of our interest (low and slow, and even 'virtually=
stopped' if force feedback were employed). Might such an axis be used wi=
th a gravitational pendulum to help avoid 'latching tendencies' of the type=
maverick Peters has in times past suggested (and thus been more than once=
labeled 'crazy'-and encouraged by a select few (like outstanding Emeritus=
Professor of Physics Tom Erber at Illinois Tech) to 'keep on keeping on' a=
nd hope by the grace of God that there might eventually come a time in whic=
h to say I told you so. Incidentally, Tom told me years ago: "Randall, wh=
en your work finally becomes mainstream, watch out for the 'steam-rollers'.=
He recognized the remarkable (dog eat dog) tendency of far too many in t=
he world of science who try to claim credit for something that was the semi=
nal contribution of another and over which its creator may have labored for=
decades with nobody other than a select few ever paying attention and prov=
iding him encouragement.
If you've read everything this far, I commend you (not knowing whethe=
r I should apologize),
Randall
This message has=
nearly ‘grown without bounds’, and so you may want to go strai=
ght to the last three paragraphs (if you have any interest whatsoever).
Brett, I am glad to hear of how you bake the =
spring to hasten stability. In some of my experiments performed=
in vacuum it was necessary to bake the entire chamber, as is common practi=
ce by those who do high vacuum studies. Otherwise, diffusion pumping =
that follows mechanical pumping will never allow one to attain the pressure=
s being sought. These real world frustrations, that are well kn=
own to members of ‘vacuum societies’, point vividly to the fact=
that the physics is even more complicated than just defects/dislocations i=
n an otherwise perfect material that we envision (erroneously) as existing =
in no other state than that which we call ‘solid’. In oth=
er words, what has been the focus of our discussion (a spring) is also infl=
uenced at the ‘defect’ level even by the gases of the atmospher=
e in which it operates! (And incidentally, the surface of a solid is =
the ‘quintessential’ defect that cannot be avoided, since the &=
#8216;perfect’ solid must be of infinite extent.)
&nbs=
p;If one altogether doubts that gases don’t probably always play some=
role, at least at some level (perhaps insignificant, but how can such a cl=
aim be made without experimental proof) consider an experiment involving a =
shape memory alloy that I performed several years ago, which produced the a=
rticle titled “Study of friction at the mesoscale using Nitinol shape=
memory alloy” http=
://arxiv.org/html/physics/0308077
Yo=
u will see from this work what is indisputable evidence that gases can sign=
ificantly influence mechanical properties in ways that are not commonly kno=
wn. The quality factor differences for the oscillations that are them=
selves of different Q, according to whether the material is in the martensi=
tic phase or the austenitic phase—are responsible for a profound R=
16;declaration’ about the importance of defects/dislocations to a spr=
ing type oscillator. And the manner in which significant phase noise =
was found to be present, along with ‘Brownian motion’, means th=
at the low-level fluctuations are exceedingly complicated and never complet=
ely reproducible. I have facetiously said to colleagues through the y=
ears: “Guess I will have to report my findings in the journal o=
f non-reproducible results”. If such a journal actually e=
xists, no bonafide scientist would go read anything published there, becaus=
e the very ‘heart and soul’ of science is reproducibility =
; Consequently, most of my research publications have been ‘open=
access’; and the Google search engine seems to have become my greate=
st ally. I was denied promotion years ago in Texas and the dean who s=
ealed that decision wrote in her letter, “I hope Professor Peters wil=
l eventually be able to say I told you so”--concerning my studies of =
the mesodynamics of mechanical systems. Just as I was retiring =
this past spring, one of the most significant publications of my career was=
about to be published in Physical Review E (highly esteemed refereed journ=
al that is the antithesis of open access publishing). Less than a yea=
r before this, two distinguished French (nonlinear) math/physics experts ha=
d found one of my papers dealing with catastrophes. I had published t=
hat article only in one place (Mercer physics personal homepage) believing =
(based on painful experiences with referees) that it had about a ‘sno=
w ball’s chance in hell’ of ever getting published ‘=
;conventionally’. Following the request by my later-to-be co-au=
thors, I performed an experiment that resulted in our article “Predic=
tion of catastrophes—an experimental model”. As it was co=
ming together I made a claim to colleagues that proved to be ‘right o=
n target figuratively’—“there’s not a referee in he=
ll who will dare reject this paper, because of the outstanding reputation o=
f my co-authors”. (You can readily read the abstract of our art=
icle by simply typing ‘prediction of catastrophes’ into Google =
without the tick marks of a literal search. You should be able also to easi=
ly with Google find the complete preliminary article that was open source p=
ublished on arxiv.) I mention this to you list-serve readers for anot=
her reason—which if it should ever prove to be profound—remains=
yet (only after a long time, if ever) to be seen. If you will look a=
t the following paper: http://physics.mercer.edu/hpage/acceleromete=
r/accelerometer.html
You will see wh=
at is an event that preceded an earthquake. It is of the type that I =
have seen (in a related context, also by Michael Phillips in Australia; who=
calls one type the “Randall effect’) quite frequently as tanta=
lizing evidence for ‘precursors’ to earthquakes. At this =
point in time, anybody making a claim for the possibility of meaningful =
216;early warning predictors’ of an earthquake (that could save lives=
) is viewed as either a (i) mystical quack, or an (ii) ignoramus masqueradi=
ng as a scientist. The basis for such a position is not without justi=
fication, since true earthquake prediction is a ‘holy grailR=
17; type of quest, afflicted with the greatest of scientific challenges.&nb=
sp; I personally believe, however, that professional seismologists have not=
been ‘asking the right questions’ relative to the matter. =
; Just like Nobel Laureate Charles Townes has said the same thing about tho=
se who are life science specialists. It is easy to ‘fold one=
217;s hands’ and say “the problem will never be solved”.&=
nbsp; Certainly more physics has been brought meaningfully into cutti=
ng edge biology of late, and the same is sorely needed in seismology. =
I have had little success in my efforts to relate meaningfully with profes=
sional seismologists, which is part of my reason for coming to your amateur=
world several years ago. One of my ‘successes’ with the =
pro’s was nevertheless realized a few years ago with my BSSA pu=
blication titled “Tutorial on gravitational pendulum theory applied t=
o seismic sensing of translation and rotation”. This article wo=
uld never have happened had I not met the great John Lahr, who like myself =
had a burning passion for science education. And that passion o=
f his ‘spilled naturally’ into your world, which is the place w=
here I first learned of John and his legacy. I was greatly pleased to=
learn how the genesis of his passion was undoubtedly part of his earliest =
university degree (B.S. in Physics from Rensselaer in 1966).
The way my =
tutorial materialized is an example of how the butterfly effect of Ed=
Lorenz suggests meaningful extrapolation beyond his original statement (&#=
8220;Can a butterfly flap its wings in Brazil and cause a tornado in Texas&=
#8221;, article presented in the early ‘60’s at a Washington D.=
C. meteorology conference—about his serendipitous discovery of the &#=
8216;sensitive dependence on initial conditions that is the foundational pa=
rt of chaos). In the broader social sense, I see it (involving system=
s even more complex than atmospheric convection) to describe how “lit=
tle events of life can unexpectedly take on unforeseeable monumental propor=
tions”. Early after my use of the first fully differential capa=
citive sensors I became enamored with the pendulum, one of the oldest instr=
uments of science. Few people know the full extent to which the gravi=
tational pendulum in its ‘simplest’ form has impacted our world=
.. Even the foundation theories of fluid mechanics (Navier-Stokes equa=
tions) derive from studies of the pendulum that were performed by the legen=
dary George Gabriel Stokes. Those in turn influenced even the world o=
f meteorology where Lorenz is considered the father of chaos theory. =
Stokes famous-to-physicists theorem, that derived from his pendulum studies=
, describes the manner in which only small rain droplets in clouds have a s=
mall enough Reynolds number to remain part of the cloud, while under the in=
fluence of the earth’s field of gravity type (little g). In his=
paper generated in 1850 (“On the effect of the internal fricti=
on of fluids on the motion of pendulums”) Stokes rightly predicted th=
at his conclusions would have significant impact on the world of meteorolog=
y.
=
Another of my experiences involving butterfly effects of =
social type (that involved the sequential outworking of more than just one)=
‘revolved’ around the article that I wrote for the 10th edition of the McGraw Hill Encyclopedia of Science and Technolog=
y. My article accompanies one that was written by Lorenz before his d=
eath, and another piece written by a physics theorist who was at Georgia Te=
ch (quantum mechanics expert named Joseph Ford. Ford was the th=
eorist who singularly laid the theoretical foundation for my experimental d=
issertation work at Oak Ridge National Laboratory in the 1960’s. =
; And my major professor (Mack Breazeale) who worked with Ford, was associa=
ted in his research with the one who became my on-site mentor at ORNL=
, named Victor Pare’ (now 84 years of age). Because Dr Pa=
re’ is an expert in material properties, through his training for the=
PhD at Cornell University—I was circumstantially exposed to valuable=
concepts involving defects that are not well known the way they should be.=
Who could imagine such a chain of butterfly effect events, occurring=
in two widely separated-in-time parts of my life, yet having such synerget=
ic influence on my practice of physics.
By the way, when I w=
as working with single crystalline copper, it was not useable before being =
work hardened by fast neutrons from the ‘swimming pool’ reactor=
at the x-10 plant, to pin dislocations. Had our crystals not been so=
expensive, we envisioned a ‘party prank’ in which we would giv=
e one of our long (right circular) cylindrically shaped specimens to a R=
16;weakest’ female present at our party and have her with both hands =
(easily) bend it into a horse-shoe shape. We would then ask the ̵=
6;strongest’ male present to come up and restore it to its original c=
onfiguration. Of course there would have been great laughter at his f=
utile attempt to correct what would have been so easy for the woman. =
The crystal would have been for her, not quite as soft as butter. But=
for him, though it would not have been strong as steel, it would hav=
e been a heck of a lot tougher than anybody other than ourselves could ever=
have imagined. The reason is because of the entanglement of dislocat=
ions that would have resulted from the woman’s bending—dislocat=
ions that start at the end surfaces and work their way inwardly to in=
teract and result in work hardening.
I say all this, without hopefully boring =
the majority of list-serve readers—because I would love to see more o=
f you change your thinking about the abiding great value of the ‘simp=
le’ pendulum. Some of the pro’s have already begun =
to change their thinking about the pendulum. Better part of a century=
ago they began to divorce themselves in their thinking from it, but there =
is a ‘remnant’ that is coming back. The California PhD wo=
rk of Ortego, under the supervision of Berger, Zumberge, and Wielandt speak=
s to the matter. (And Brett, I think I saw a webpage of yours that re=
ferences the work??) Their state of the art instrument uses optical (=
interferometric) sensing, but my expectation is that it could just as well =
have used a capacitive sensor (yielding a comparable performance level) if =
it had employed a fully differential form. Wielandt still refers to R=
.. V. Jones as the ‘ultimate authority’ when it comes to sensing=
of seismic inertial mass motion—whether for purpose of an error sign=
al based on force feedback, or as is done in my VolksMeter which uses a =
216;simple’ pendulum that is not influenced by an actuator. Jus=
t another example of the butterfly effect involves my creation of the first=
fully differential capacitive sensor types. My attempt to get a pape=
r published was met with incredible resistance from some ignoramus referees=
.. Eventually the editor at Rev. of Sci. Instr. (Tom Braid) sent=
my paper to Jones, who gave it a positive endorsement, saying that if I we=
re ‘first’, then I should be so recognized. Jones in his =
report stated that it clearly had twice the sensitivity (of conventional &#=
8216;differential capacitive’ sensors of comparable electrode dimensi=
ons) and he ‘liked the symmetry’, but had ‘become too old=
’ to give himself to a math analysis of my devices. With his de=
ath in the late ‘90’s the world lost one of the great pioneers =
of science. Jones was even honored in this country for his WWII work =
that helped to save England from destruction by the Nazi’s and which =
also facilitated U.S. contributions to the war effort.
Should you =
believe that journal referees (and even editors) must be so wise and well t=
rained they surely couldn’t be sometimes guilty of incompetence (even=
gross form), listen now to one of the most outrageous examples of foolishn=
ess in the history of science, involving the laser and the work of Ted Maim=
an at Hughes Research Laboratories in 1960. My knowledge =
of what happened is another example of ‘butterfly effects’ taki=
ng place in the social events of one’s life. I firs=
t learned about Maiman’s treatment ‘at the hands of’ an e=
ditor of Physical Review Letters while I was at lunch with a famous physici=
st named Arthur Schawlow. Dr. Schawlow (deceased Nobel La=
ureate, who was the brother-in-law of the better known Nobel Laureate Charl=
es Townes, with whom I have also had close fellowship—another example=
of the butterfly effect) told me to ‘consider it a compliment’=
that my article that had been submitted to Physical Review Letters had bee=
n rejected. On the 50th anniversary of the creation of the=
first (ruby) laser, Nature chose to engage in a celebration of their publi=
cations over the preceding century. In one of the pieces that honored=
Maiman, http://www.press.uchicago.edu/Misc/Chicago/284158_townes.html=
Townes said of Maiman’s paper=
that was finally published in Nature: “I believe it might be c=
onsidered the most important per word of any of the wonderful papers in =
Nature over the past century”.
I just receiv=
ed an email from a horologist who is quite familiar with issues of material=
limitations—how their desire for a perfect clock will never be=
realized, any more than our desire for a perfect seismometer. =
I do believe, however, that the ‘simple’ pendulum could b=
e configured to minimize some of the ‘show-stopper’ features of=
defects, as they have all too often impacted some instruments. =
I may be altogether wrong, but at least I’ve done a lot of studies t=
hat suggest, why not finally find out from experimentation, in just what ca=
tegory to place my claims; i.e., good, bad, or ugly. In particular, B=
rett, I would ‘sing the hallelujah chorus’ if you and Dave shou=
ld choose to make the first ever ‘force feedback gravitational pendul=
um’ to function as a first of its kind horizontal seismometer/tiltmet=
er. Yes, you have been using something also called by many a pendulum=
, but Galileo who studied the first ‘true’ (gravitational, R=
16;simple’) pendulum would have recommended that you use a different =
‘descriptor’; just as I prefer to label the torsion instrument =
that was used by Cavendish to measure the universal constant (‘big=
217;) G due to Newton, by the word ‘balance’ rather than ‘=
;pendulum’. The so called torsion ‘pendulum’ of Cav=
endish works in a radically different way than the gravitational pendulum s=
tudied by Galileo and Newton. I believe that the gravitational pendul=
um, operating with radically different physics than what describes vertical=
seismometers—might allow for some important developments. The =
key to earthquake predictability, should it ever be possible—I view a=
s involving calculations of frequency domain type, using measurements at lo=
nger periods than are accessible by the vast majority of instruments. =
One of the very few instruments that easily operates there (at least witho=
ut feedback) is the gravitational pendulum, as shown not only in my many ex=
periments and a commercial product as well, but also in the dissertat=
ion of Ortego. His work was encouraged by Wielandt, who has said (in =
effect) that it was time for seismologists to stop ignoring some of its imp=
ortant capabilities. The gravitational pendulum is not prone to ̵=
6;displacement to the rails’ (whether mechanical or electronic), whic=
h was a major factor in the employment of force feedback to begin with, for=
its use in vertical instruments. Nevertheless, force balance operati=
ng with such a pendulum might open new insights, by providing a first ever =
horizontal instrument of that type.
My conclusions are influenced by the follo=
wing line of thinking. As you point out, Brett, the sensor does not r=
epresent a ‘piece de resistance’; rather the culprit will alway=
s be the components that are most subject to the large ‘load be=
aring forces’ of most instruments. Incidentally there is physic=
s first recognized by the great Richard Feynman (in his article “ther=
e’s plenty of room at the bottom” that explains why MEMS seismo=
meters are likely never to perform at the level early builders thought were=
contemplating. I could easily at this time get into a detailed discu=
ssion of Brownian motion (based in the equipartition theorem with which eve=
ry physics grad student is thoroughly versed) to prove (if my claims concer=
ning defects have any measure of truth) that seismometer performance cannot=
be properly gauged on the basis of the widespread (overly) simplistic calc=
ulation of threshold noise determined by atmospheric molecular motion. =
; It is another one of those cases like my previous “let us assume a =
spherical egg’. It is absolutely amazing to me, the tendency (t=
oward which we are all prone) to make assumptions for which the ̵=
6;baby gets thrown out with the wash’.
Consider =
the following: can we employ an axis in which the mechanical part of =
the force that supports our inertial mass (the bob) is made significantly s=
maller than what is typical, without at the same time introducing something=
new by our ‘cure’ that is worth than the ‘disease’=
(brought on by defect ‘antibodies’). Chris Chapman has p=
ointed out (rightfully) that we don’t want to place any strong magnet=
anywhere on an instrument other than where it is guaranteed to be stationa=
ry. And though I have not seen here extensive discussions of why ferr=
ous materials should also not be part of the moving members; I think it is =
rather obvious we should not use them under most circumstances. =
;But I think the ‘Chapman constraint’ (which he has in times pa=
st eloquently described to you folks) can be relaxed for the following.&nbs=
p; Consider the axis that is pictured in figure 2 of the following paper, t=
itled “Pendulum sensor using an optical mouse” http://arxiv.org/html/0904.3070v1
Most of the weight of =
the pendulum is supported by the magnetic field gradient of the rare earth =
magnet shown. Thus the force of mechanical type involving defects at =
the contact between the ball-point pen(s) and the lower magnet surface is s=
mall; i.e., the load bearing force is dramatically reduced as compared to w=
hat one finds with typical roller type bearings in a Lehman, or with ‘=
;knife edges’ of type found in old analytic chemistry type balances t=
o measure mass (they were a compound gravitational pendulum). Of cour=
se it has been well known for years the important requirement for ‘ed=
ges’ --that they be of very hard material, such as agates in the old =
balances. The experience of the old master builders of such balances =
should not be summarily ignored as we contemplate the business of def=
ect influence. To measure a mass at a level of a microgram is no smal=
l matter. And if you tried to do so with a ‘soft’ materia=
l for the ‘edges’ of your very best otherwise old instrument yo=
u would not be successful, because of the defect properties of those edges.=
Thus it is important that both parts of the axis are hard mate=
rial—tungsten carbide of the pen point and the alloy type of the rare=
earth. I also am aware of the fact that there could be some adverse =
features of the surface coating of the rare earth magnet; how it might degr=
ade with time (both chemical and mechanical) and thus impact performance.&n=
bsp; But isn’t it worth some tests? Note that not every ball po=
int pen type will work in this way. The part that holds the end ball =
must be ferrous. Many of the inexpensive ball point pens that the Bri=
ts like Chris call ‘biro’ I have found to work. Simply pl=
ace the writing point of the instrument (as purchased) up against a powerfu=
l magnet and find out if it will ‘stick’ there. I discove=
red this quite by accident several years ago while teaching an undergraduat=
e physics laboratory. With a little free time away from the usual stu=
dent assistance that was needed, I casually ‘tested the strength̵=
7; of a small rare earth magnet by placing it on the upper frame of one of =
the steel doors to the room. Finding it quite hard to then pull away =
the frame, I wondered two things: (i) would it attract my ball point =
pen?, and (ii) if so, just how strong would the attraction be? I was =
astonished at how much weight could be supported by this means, and additio=
nally by what resulted after the pen was left swinging. The Q of the =
free decay of that single-point conical pendulum was so great that it was s=
till moving by a visually perceptible amount many minutes after I had gone =
back to help my students. Some of that motion that I later saw was pr=
obably due to air current disturbances; however, subsequent study has shown=
that it has the very properties that I’m encouraging you to explore =
and hopefully exploit.
=
; So Chris, what about your thoughts on this setup?=
Can it avoid a ‘show-stopper’ consequence of unavoidable=
environmental field changes? If the ferrous holder of the tungsten c=
arbide of the pen points (required for the force of attraction) were at a p=
lace of great motion, then the answer is probably no. But consi=
der its placement that yields very small oscillatory motion, and the realm =
of our interest (low and slow, and even ‘virtually stopped’ if =
force feedback were employed). Might such an axis be used with =
a gravitational pendulum to help avoid ‘latching tendencies’ of=
the type maverick Peters has in times past suggested (and thus been =
more than once labeled ‘crazy’—and encouraged by a =
select few (like outstanding Emeritus Professor of Physics Tom Erber at Ill=
inois Tech) to ‘keep on keeping on’ and hope by the grace of Go=
d that there might eventually come a time in which to say I told you so.&nb=
sp; Incidentally, Tom told me years ago: “Randall, when your wo=
rk finally becomes mainstream, watch out for the ‘steam-rollers’=
;. He recognized the remarkable (dog eat dog) tendency of far too man=
y in the world of science who try to claim credit for something that =
was the seminal contribution of another and over which its creator may have=
labored for decades with nobody other than a select few ever paying attent=
ion and providing him encouragement.
If you’ve read everything thi=
s far, I commend you (not knowing whether I should apologize),
Randall
=