HDTenEightyP/NetNews huggingface dataset:
Organization: Penn State University
Date: Mon, 16 Nov 1992 04:01:11 EST
From: <NMR103@psuvm.psu.edu>
Newsgroups: sci.fractals
Subject: Re: Lorenz' Weather
 <1e7bmaINNslq@network.ucsd.edu>

Hey Mike Marcelais!! (it's nic from s&m)
if you want to know about the Lorenz equations, check out 2 sources:
1st is Lorenz's original paper, _Deterministic Non-Periodic FLow_
which can be found in Journal of the Atmospheric Sciences of some
month in 1963.
Another really great source, written by some students in my dept.
and edited by an awesome instructor here at PSU, is _Lecture Notes
in Physics_, the one on Nonlinear Hydrodynamic Modeling. The
editor is H.N. Shirer. You want to check out chapter 2.
-nic
Newsgroups: sci.fractals
From: rbw3q@rayleigh.mech.Virginia.EDU (Brad Whitehurst)
Subject: Re: Lorenz' Weather
Organization: University of Virginia
Date: Thu, 19 Nov 1992 23:38:04 GMT

In article <1e7bmaINNslq@network.ucsd.edu> mbk@lyapunov.ucsd.edu (Matt Kennel) writes:
>mroussel@alchemy.chem.utoronto.ca (Marc Roussel) writes:
>: >	dX/dt = a(Y-X)
>: >	dY/dt = bX-Y-XZ
>: >	dZ/dt = XY - cZ
>: >
>: >				where a = 10
>: >				      c = 8/3
>: >				      b = control parameter (try 28)
>: 
>:      These are indeed the Lorenz equations (as they are now known) but
>: these aren't the original weather simulation equations where Lorenz
>: noticed sensitive dependence on initial conditions.  Lorenz actually
>: started out with some specialized version of the Navier-Stokes equation
>: (a PDE) and noticed sensitive dependence in these equations under the conditions
>: of his weather simulation.  The Lorenz ODEs shown above are a truncation
>: of the Navier-Stokes equation for the special case of (I think)
>: Rayleigh-Benard convection under certain fairly restrictive conditions.
>
>There is a physical system for which the Lorenz equations are a
>"not incredibly bad" approximation (to use them for simple R-B convection is a 
>"well that's really pretty cheezy" approximation).
>
>It's called a thermosyphon, and it actually gets used for some engineering
>applications but I don't know how really.
>
>Think of a loop of pipe in an 'O' standing up vertically, like a bicycle
>wheel, with fluid in the interior.
>
>Now, keep the walls on the bottom half of the "O" hot, and the
>walls on the top half cold. Given enough of a temperature difference,
>you can start to get convective motion of the fluid as it tries to
>transport heat from hot to cold.
>
	Quite a lot of solar heating systems were/are set up that
way.  They are not as high performance as forced circulation, but
then, they don't have all the hardware, either.  The cooling systems
in some old engines were thermosyphon also.  And any process where you
are heating a vessel from the bottom could exhibit this behavior,
couldn't they?  (you'd have convection cells, rather than water
running in a pipe, though)

-- 

Brad Whitehurst    |   Aerospace Research Lab
rbw3q@Virginia.EDU |   We like it hot...and fast.
Newsgroups: sci.fractals
From: cliff@watson.ibm.com (cliff)
Subject: Offer to Colorize Data
Date: Tue, 17 Nov 1992 14:19:12 GMT
Disclaimer: This posting represents the poster's views, not necessarily those of IBM
Organization: A

Offer to Represent Data in Color                                                
                                                                                
I am testing a data-colorizer program which converts an array of numbers        
(such as in an image, microscopic or mathematical surface, etc.) to a           
colored image in visually useful ways.  If you have an array of data            
which you would like to represent in novel, colorful, and scientifically        
or artistically useful ways, I may be able to return a slide of your            
data to you after conversion by the colorizer program.  The program is          
useful for revealing patterns not easily seen with simple color maps.           
Please send a note to cliff@watson.ibm.com for more information.                
Be sure to tell me where you're from and what your're working on.
From: john.gialuco@satalink.com (John Gialuco) 
Newsgroups: sci.fractals
Subject: Saving
Date: 19 Nov 92 19:02:00 GMT
Distribution: world
Organization: Datamax/Satalink Connection * Ivyland, PA (215) 443-9434
Reply-To: john.gialuco@satalink.com (John Gialuco) 

        I have been trying to save a gif after I generate it using a
'ram video' resolution in the background of Fractint 17.2 (one of the
higher resolutions which my screen cannot show). When I try to save the
file I get an error message saying that the file cannot be saved. I
am planning to send the files off to a graphic house where the fractals
will be put into a photographic negative. I will then be photographically
enlarging the negative to a print for showing at an art gallery.
        I do have the 'Fractal Creations' book but I am still unable to
find a solution. If anyone has a solution I would appreciate it. The
fractals that I print out on a Techtronix color printer just doesn't do
the picture justice.
                                            
Newsgroups: sci.fractals
From: lmitchel@nyx.cs.du.edu (lloyd mitchell)
Subject: "Critical Points" for non-analytic functions
Summary:   Are there any?
Organization: University of Denver, Dept. of Math & Comp. Sci.
Date: Sat, 21 Nov 92 15:40:35 GMT

In sci.math, a question was asked about taking the derivative of a non-
analytic complex function.  In particular, the poster was trying to 
differentiate

	f(z) = y + ix, where z = x + iy.

My question is this:  For such functions, is there any such point that
corresponds to a critical point for analytic functions?  I'm curious
because I'd like to generate Mandelbrot-type sets for some functions of
this nature, and I wonder where one would begin iterating.  (For analytic
functions, Mandelbrot images are generated by beginning the iteration
at a critical point.)

Thanks for any info,
Kerry Mitchell
Newsgroups: sci.fractals
From: frank@cwis.unomaha.edu (Frank Hartranft)
Subject: Re: Newton's Method
Organization: University of Nebraska at Omaha
Date: Mon, 23 Nov 1992 19:29:32 GMT

Once you get used to Newton's Method to solve iterative functions,
you can make up your own.  Try one with just real roots, like
(x^2 - 4) that will give you vertical lines (no imaginary part)
Then try one with two real and one imaginary root.
(I messed with the colors in x^3-1 and got a real striking fractal
with the real root in blues, one imag root in greens, and the
other in reds...)
If you want a striking pattern, try x^4-1=0.  That gives two real and
two imaginary roots.  Apply Newton's Method, and you get one that has
you saying "Wow!"

Frank Hartranft
-- 
Frank@unomaha.edu
Newsgroups: sci.fractals
From: Gabriel Landini <g.landini@uk.ac.bham>
Subject: Re: Syntax for the L-Systems part of FractInt?
Date: Mon, 16 Nov 1992 16:35:24 GMT
Organization: The University of Birmingham, United Kingdom

>I was under the impression that L-systems were generated by IFS codes.
>Am I completely wrong in this assumption? For example, the top half of
>the Koch curve can be generated by replacing one line segment with
>four segments, each 1/3 the length of the original (kind of looks like
>this: _/\_ ) --- each of these line segments can be considered a
>transformation with a set of IFS codes attached to it. Would this
>be a correct definition of L-system?
>------------------------------------------------------------------------------

Both things are incorrect. You can draw some fractals by the 2
methods (IFS & L-systems).

While the IFS does affine transfromations of the space, with a L-sys
you re-process a string. L-sys are like the logo turtle: go north.
turn left 45, etc but with recursion on the same string. ;-)

Gabriel
Newsgroups: sci.fractals
From: gordon@tramp.Colorado.EDU (GORDON ALLEN R)
Subject: Re: Lorenz' Weather
Organization: University of Colorado, Boulder
Date: 20 Nov 92 16:43:23 GMT

rbw3q@rayleigh.mech.Virginia.EDU (Brad Whitehurst) writes:
>>
>	Quite a lot of solar heating systems were/are set up that
>way.  They are not as high performance as forced circulation, but
>then, they don't have all the hardware, either.  The cooling systems
>in some old engines were thermosyphon also.  And any process where you
>are heating a vessel from the bottom could exhibit this behavior,
>couldn't they?  (you'd have convection cells, rather than water
>running in a pipe, though)

>-- 

>Brad Whitehurst    |   Aerospace Research Lab
>rbw3q@Virginia.EDU |   We like it hot...and fast.


A couple of fairly recent applications include some very inexpensive solar
hot water systems, that circulate heated water from the collector to the 
storage tank by virtue of the convective effect.

There is a device that uses heat from a wood stove to heat water in a coil
 that rises to a special condenser above the stove.  The heated water then 
circulates around a closed heating loop and back to the coil in the stove.

Its all 'passive'.  Is not the old coffee percolator an example of this effect?

allen
-- 
Allen Gordon 		         *If the folly of but one of us was changed to*
Research Associate         	 *intelligence, and divided amongst a thousand*
gordon@tramp.colorado.edu   	 *toads, each would be more intelligent than  *
				 *Aristotle				      *
Newsgroups: sci.fractals
From: Gabriel Landini <g.landini@uk.ac.bham>
Subject: Re: Wanted information
Date: Mon, 16 Nov 1992 09:59:12 GMT
Organization: The University of Birmingham, United Kingdom

>Hi!
>I am a grad. student in mining engg. trying to do work on size and shape analys
>is of dust particles.I am new to subject of fractals, but it seems it can have
>a lot of application in my field. I will be thankful if you can provide some
>starting information ( about books, articles etc. ).
>Thanks in advance
>Praveen Sharma
>pxs121@psuvm.psu.edu
>------------------------------------------------------------------------------

Read: "A random walk through fractal dimensions" by Kaye.(book)
G.Landini@bham.ac.uk
Newsgroups: sci.fractals
From: yavuz@bnr.ca (Yavuz Onder)
Subject: Re: Postscript from FRACTINT-inverted image.
Organization: Bell-Northern Research, Ottawa, Canada
Date: Thu, 19 Nov 1992 18:24:41 GMT

I have never used this, but there is a postscript  parameter called
"translate". The doc says it will do what you want.
--
Yavuz Onder     |  Bell-Northern Research Ltd.    | My opinions aren't
(613)-763-2294  |  P.O. Box 3511 Station C        | necessarily BNR's,
yavuz@bnr.ca    |  Ottawa, Ont. CANADA  K1Y 4H7   | or vice versa.


Newsgroups: sci.fractals
From: rbw3q@rayleigh.mech.Virginia.EDU (Brad Whitehurst)
Subject: Re: Lorenz' Weather
Organization: University of Virginia
Date: Fri, 20 Nov 1992 22:42:19 GMT

In article <gordon.722277803@tramp.Colorado.EDU> gordon@tramp.Colorado.EDU (GORDON ALLEN R) writes:
>rbw3q@rayleigh.mech.Virginia.EDU (Brad Whitehurst) writes:
>>>
>>	Quite a lot of solar heating systems were/are set up that
>>way.  They are not as high performance as forced circulation, but
>>then, they don't have all the hardware, either.  The cooling systems
>>in some old engines were thermosyphon also.  And any process where you
>>are heating a vessel from the bottom could exhibit this behavior,
>>couldn't they?  (you'd have convection cells, rather than water
>>running in a pipe, though)
>
>A couple of fairly recent applications include some very inexpensive solar
>hot water systems, that circulate heated water from the collector to the 
>storage tank by virtue of the convective effect.  

	Actually, that kind of solar heater has been popular since the
late '60s for pool heating and household hot water, esp. in the solar
heyday of the oil embargo era.  (Remember those fun Whole Earth
Catalogs??)
>
>There is a device that uses heat from a wood stove to heat water in a coil
> that rises to a special condenser above the stove.  The heated water then 
>circulates around a closed heating loop and back to the coil in the stove.
>
	Also the "heatilator" fireplace inserts.  Some are fan driven,
and some are passive.

>Its all 'passive'.  Is not the old coffee percolator an example of this effect?

	Actually, a percolator cheats.  It has a check valve in the
stem of the basket.  Also, it may depend on a little local boiling to
get a 2 phase flow.
>
>allen
>-- 

Brad

-- 

Brad Whitehurst    |   Aerospace Research Lab
rbw3q@Virginia.EDU |   We like it hot...and fast.
From: gardner-justin@cs.yale.edu (justin gardner)
Newsgroups: sci.fractals
Subject: Re: Syntax for the L-Systems part of FractInt?
Date: 17 Nov 1992 23:02:36 -0500
Organization: Yale University Computer Science Dept., New Haven, CT 06520-2158
Distribution: world
NNTP-Posting-Host: lion.zoo.cs.yale.edu


L-systems (Lindenmeyer systems) start with an axiom string and use production
rules to create new strings. For example,

Axiom: aabc
Production rules: a -> ab
                  b -> c
                  c -> c

All production rules are applied in parallel, so the string might develop as
follows:

aabc
ababcc
abcabccc
abccabcccc
etc.

So, how is this string graphically interperted? An interpertation based
on LOGO called turtle interpertation is used. A turtle in LOGO, follows simple
rules to draw pictures on the screen. A turtle can be told to move forward and
turn angles. In a string:

  F - can be used to tell the turtle to move forward a set distance,
      drawing a line behind it. 
  f - can be use to tell the turtle to move forward a set distance,
      without drawing a line behind it.
  + - turn to the left a set angle.
  - - turn to the right a set angle.

Even with just these simple rules, fractal shapes can be generated.
Here is one taken from _The Algorithmic Beauty of Plants_, Prusinkiewicz
et al. pp. 9.

Axiom: F-F-F-F
Production Rules: F -> F+FF-FF-F-F+F+FF-F-F+F+FF+FF-F
	          - -> -
                  + -> +

This L-system generates a koch curve. Many further refinements of this basic
scheme have been used to model the branching and flowering patterns of trees
and plants, as well as the development of cells in simple animals. _The
Algorithmic Beauty of Plants_ is a fairly easy to read introduction to the
subject that contains many pictures (and is thus a little bit pricey).

justin
From: spedpr@thor.cf.ac.uk (Paul Richards)
Newsgroups: sci.fractals
Subject: Introductory talk
Date: 18 Nov 92 15:21:04 GMT
Organization: University of Wales College at Cardiff
X-Mailer: Cardiff Computing Maths PP Mail Open News Gateway

I have to do a seminar next week on fractals and I was looking for some
advice. I've only just started looking at fractals as part of my Phd and
I was wondering what are the key issues to bring out in such a
discussion. Are there "standard" images that everyone uses and if so
where can I get them from.

Also, I am looking at ways of using fractals with neural networks. Are
there any papers relating to this. Any combaination of the two in
whatever way would be of interest at the moment.

Please reply by mail.

Thanks.
-- 
  Paul Richards at Cardiff university, UK.

  spedpr@uk.ac.cf.thor	Internet: spedpr@thor.cf.ac.uk
  UUCP:     spedpr@cf-thor.UUCP or ...!uunet!mcsun!uknet!cf!thor!spedpr
+++
Newsgroups: sci.materials
From: weiyi@eng.auburn.edu (Wei Yi Wu)
Subject: mobility of electrons and/or ions in alumina	
Reply-To: weiyi@eng.auburn.edu
Organization: Auburn University Engineering
Date: Thu, 19 Nov 1992 04:13:39 GMT

Can anyone help me find out the mobilty of electrons/holes in alumina?
Is there any data available about the anisotropic diffusion coefficients
of Al and O ions in alpha alumina?   



Newsgroups: sci.materials
From: elepcj@nuscc.nus.sg (Helen Peng)
Subject: Selective Etchant for AlgaAs...
Organization: National University of Singapore
X-Newsreader: Tin 1.1 PL4
Date: Thu, 19 Nov 1992 05:18:01 GMT

HI,
Is there anyone who  knows the selective etchant  to remove Al.3Ga.7As
layer but not GaAs Layer?

Thanks for your attention/help.

Newsgroups: sci.materials
From: john@aquarius.unm.edu (John Prentice)
Subject: Re: Cold Fusion
Date: Fri, 20 Nov 92 18:37:44 GMT
Organization: Dept. of Physics & Astro, University of New Mexico, Albuquerque
Keywords: Cold Fusion, Hydrogen, Paladium

In article <1992Nov20.070621.26629@athena.mit.edu> dwalton@athena.mit.edu (Dave Walton) writes:
>Hi there.  I was in my quantum class today and my professor, Keith Johnson,
>started talking about Cold Fusion, or at least, what was thought to be
>cold fusion.  He said that what was actually being witnessed wasn't a nuclear
>reaction at all (big surprise) but a new type of phase transformation of
>hydrogen in the paladium.
>
>  [some stuff deleted] 
>
>I am interested in this topic and would like to hear some more detailed 
>explanations of the mechanisms going on (speculation is fine since the exact\
>mechanisms are still not completely understood) along with some response to
>why the United States thought that this was a technology unworthy of attention,
>whereas Japan realized that something was there and followed it.

I have not followed the cold fusion stuff recently, but unless something very 
recent has come out, the phenomena has been rather discredited.  In either
case, I am under the impression that there is still no consensus on whether
excess energy is being produced, chemical or otherwise.  There was a cold
fusion conference a few weeks ago, seems to me that someone or another made
yet another claim for excess heat, but at this point the world is wise to be
exceedingly cautious in accepting such claims.  I am particularly skeptical
that anyone is making industrial use of this phenomena, I rather expect this
is more rumor than fact.  I have heard that some Japanese companies have
backed some cold fusion research, but that is a bit different than saying they
are working on prototype industrial applications.  If they are, someone is
missing out on a Nobel prize by not announcing their results.  Take it all
with a megaton of salt :-) .

If you are interested in this subject of cold fusion, you might want to check
out sci.physics.fusion (I think this is the right name).  I am pretty sure
it is still active.  There is an unusually low signal to noise ratio in that
newsgroup, but it can be fun to read.


>P.S.  1) This is my first posting, so sorry if it doesn't meet some standard
>            or another.

Your disclaimer is unnecessary, this is what UseNet is all about.   As for
not meeting some standard or another, your posting was alot more interesting
than alot of them :-) .  Keep on posting!

John
-- 
Dr. John K. Prentice                      
Quetzal Computational Associates    
3200 Carlisle N.E., Albuquerque, NM   87110-1664  USA
Phone: 505-889-4543  E-mail: quetzal@pinet.aip.org -or- jkprent@cs.sandia.gov
Xref: sparky sci.materials:905 sci.engr.mech:544
From: pkbhatti@kopth004.delcoelect.com (Pardeep K. Bhatti)
Newsgroups: sci.materials,sci.engr.mech
Subject: Re: common solder materials
Keywords: mech props, solder materials
Date: 18 Nov 92 20:23:11 GMT
Organization: Delco Electronics Corp.

In article <1992Nov18.161229.11293@engr.uark.edu> bic@engr.uark.edu (CHANDRAN BIJU I) writes:
>Is anyone out there familiar with a book or an article listing the mechanical
>properties (Youngs modulus, etc.) of common solder materials.
> 

Welcome to the exotic world of solder materials!!!
It is very difficult to get good, reliable data on mechanical properties of
solder materials. Most common solder materials have highly nonlinear
constitutive stress-strain relationships, which are also very temperature
dependent. Furthermore, they exhibit creep and plasticity phenomena which
dominate their mechanical behavior in their normal operating temperature
range.

There is very limited solder property data in books, but there are a good
number of technical papers on this subject. A good starting point will be
the ASME Journal of Electronic Packaging and IEEE Transactions on Components,
Hybrids, and Manufacturing Technology (CHMT). Also check proceedings from
ASME WAM conferences from recent years. However, there is a wide variation
in the published solder property data in the literature. For example, there
is a 5 to 1 variation in the reported Young's modulus figures for the most
common solder (63/37 Sn-Pb).

Good luck with your search...
-- 
Pardeep K. Bhatti                         pkbhatti@kopth004.delcoelect.com
Delco Electronics Corporation
GM Hughes Electronics
***  The opinions expressed are mine, not necessarily of my employer.  ***
Newsgroups: sci.materials
From: john@aquarius.unm.edu (John Prentice)
Subject: Re: Cold Fusion
Date: Fri, 20 Nov 92 19:04:42 GMT
Organization: Dept. of Physics & Astro, University of New Mexico, Albuquerque
Keywords: Cold Fusion, Hydrogen, Paladium

In article <1992Nov20.070621.26629@athena.mit.edu> dwalton@athena.mit.edu (Dave Walton) writes:
>Apparantly, Toyota has cought on to this new type of energy (well, not new, 
>just mis-understood) and is currently funding Pons and Fleishman (sp?) at
>a lab in France.
> [etc...]

This may be of interest, this is from "What's New", a weekly announcement
of interesting (mostly political) physics news from the American Physical
Society:

   IS COLD FUSION PRACTICAL?  IT IS IF YOU OWNED STOCK IN NTT
   prior to the Third International Cold Fusion Conference in Nagoya
   on 21 Sept.  Two scientists from Nippon Telephone and Telegraph
   held a press conference to announce that they had detected excess
   heat and helium in a reproducible cold fusion experiment.  NTT
   stock rose 11% on the news. NTT is one of the biggest stock
   capitalization companies in the world. The paper profits after
   the cold fusion announcement were nearly $8 billion.

The phenomena might well be imaginary, but the profits evidently
aren't !

John
-- 
Dr. John K. Prentice                      
Quetzal Computational Associates    
3200 Carlisle N.E., Albuquerque, NM   87110-1664  USA
Phone: 505-889-4543  E-mail: quetzal@pinet.aip.org -or- jkprent@cs.sandia.gov
Newsgroups: sci.materials
From: cjs1722@zeus.tamu.edu (STEPANIAN, CHRISTOPHER JOHN)
Subject: Re: Meterials that hard/soften with applied voltage
News-Software: VAX/VMS VNEWS 1.41    
Organization: Texas A&M University, Academic Computing Services
Date: Sat, 21 Nov 1992 00:06:00 GMT

In article <BxxsAw.Kq7@aplcenmp.apl.jhu.edu>, doherty@aplcenmp.apl.jhu.edu (Kevin Doherty) writes...
>esm40@cd.amdahl.com (Ed McGettigan) writes:
> 
>>Does anyone know of any materials/liquids that harden when you apply
>>a voltage/current to them and revert when you turn it off?
> 
>  Think there's a whole family of such materials-called (I believe)
>electrorheologic materials.
> 
>  The ones I've heard of tend to be used in magnetic clutches and the
>like.  They consist of thick oils loaded with powdered steel-under the
>influence of a magnetic field the material 'solidifies' (the powder
>consolidates).  The stuff would likely behave the same if you ran a
>current thru it (because of the resulting magnetic field).  No problem
>that it's an insulator-one variety of this stuff uses mercury as a
>matrix.

I seem to remember seeing a paper a short while back that used this 
fluid in pads attached to the gripping surface of a robotic arm. The
hand grips the part and then volage is applied thereby securing a custom
gripper for the part. Kinda cool idea, huh!

chris
Newsgroups: sci.materials
From: kimmel@cortex.sai.vtt.fi     (Jyrki Kimmel)
Subject: Re: Jeopardy
Organization: Technical Research Centre of Finland (VTT/SAI)
Date: Thu, 19 Nov 1992 06:31:41 GMT

In article <1992Nov18.141110.26792@ncsu.edu> kester@mte.ncsu.edu (Dan Kester) writes:
> A couple of nights ago a materials scientist won in the semi-final round of
>Jeopardy! This is in their annual "Tournament of Champions".

Is this considered as a major achievement
among materials scientists?????

Jyrki

-- 
Jyrki Kimmel, VTT Medical Engineering Laboratory kimmel@cortex.sai.vtt.fi
signature in proposal in peer review phase (PPRP). Proposed motto:
"El{m{ on kivaa!" ("Life is fun!")  -Kaisa-Maria, age 3
Newsgroups: sci.materials