Newsgroup sci.engr.mech 27641

Directory

>I am an electrical engineer (degrees, employment record, and
>professional society membership to prove it) but the old man knows
>more about electrical machinery than I do (among other things of a
>more mechanical engineering bent), and probably knew more twenty
>years ago than I will _ever_ know.
Hmmmm.. an honest admission from a grad student....
>
>Now, granted, my view on this particular case in point is a bit
>jaundiced.  
Yes we are in agreement here....
>He _is_ my old man, of course.  But I can't for a moment
>believe he is unique, nor would I hesitate to extend the same respect
>to a coworker who didn't have a degree but had 40 years of practical,
>either.
Hmmmm.. an honest admission from a grad student.... this is good....
>
>I'd like to hear ideas on how to protect the title of the engineer,
>without resrting to silly tests or excluding simple practical
>knowledge.
Try this.  Tell your professor's you don't believe in silly exams.  You deserve the 
grad degree anway.
You seem to be a very bored grad student with a lot of free time to blow out 
hot air about subjects you appear to know little about.
>
>--
>John S. Novak, III           jsn@cris.com
>http://cegt201.bradley.edu/~jsn/index.html 
>The Humblest Man on the Net

> Emotionally, I agree with you. 
In Australia there is a move for us with a degree and association (pass an
entrance test/criteria) to the Institute of Engineers Australia to be
called Professional Engineers.  Those with other qualifications such as a
diploma, tech level or industry experience are not entitled to the use of
Professional just Enginner.  I agree that there are two many 'Engineers'
out there.  Ever been asked what sort of train you drive!!!!!  Or, can you
have a look at my car for me!
Bill

Mu Metal is a roughly 76% Nickel, 20% Iron, 4% Molybdenum alloy.
US manufacturers include Spang, CarTech, and Inco.  It is generally
available only in foil and sheet, and is used primarily for magnetic
shielding applications.  If you contact any of the manufacturers,
they'll be glad to tell you (and sell you) what you need.  CarTech has a
web page at , but I haven't looked for Spang or
Inco. 
Lee Gearhart   Metallurgical Engineer  lgearhart.inc@moog.com

homer@ccinet.ab.ca wrote:
> 
> I disagree with Greg Jackson. The public should be protected thru
> legislation from people who have not qualified as a Professional
> Engineer by the way of provincial (Canada) laws. People with a Phd and
> umpteen years experience can still make mistakes. The legislation also
> provides a uniform method of evaluating the experience. That evaluation,
> along with the educational and character reference will determine if
> that person should be licensed to use the title Professional Engineer
> and practice engineering.
> 
> Lets face it. Engineers build things that can threaten the lives of
> people (cars, bridges, space shuttles etc). That work must be regulated.
> Reducing the threat to peoples lives is the everyday work of an engineer
> in his practice. This is much the same as the end result of the work of
> a medical doctor. I do believe that the medical profession and the MD
> designation are regulated.
> 
> BoydI wasn't aware the the bestowing of a PE made you omnipotent!  People 
with PEs make mistakes also.  They are then bigger targets for the legal 
profession as well.  Uust as MDs who make mistakes are.

First, some background. I got a degree in Applied Mechanics from the
University of California at San Diego in 1983. That school lost its 
accreditation a year after I enrolled.
Since then I have somehow managed to accumulate 13 years of design
experience, with the words "Development Engineer" on the business 
cards my first corporate employer printed up for me, and the title 
"Mechanical Engineer" at my two subsequent places of employment.
I have never killed anybody, even when my designs had the chance.
The state of Montana (where I live and work) sent me the regulations
pertaining to PE registration, and I don't qualify. I need to have worked
under the direct supervision of a PE for some-odd years with steadily 
increasing engineering responsibility. The latter of these two 
qualifications is no problem--I've been the only ME at my last two 
places of employment, but I've never worked under a PE.
I don't even *know* a PE.
No big deal, I still have a job and the industrial exemption lets me call
myself an engineer, at least during the day, but I'd like to be able to 
call the design moonlighting I do "engineering" without threat of huge
civil penalties. 
Should the people who design bridges and skyscrapers be licensed?
It surely gives the public (at least in the abstract) some comfort to know
that those who plan the work that could kill them were qualified. That
doesn't mean that the qualification should be a restraint of trade, 
guaranteeing a monopoly to those who have jumped through all the right
hoops.
I suppose I could go beg for a job from a PE and sharpen pencils for a
few years waiting for my chance to join the big leagues, but I think I've
proven myself quite nicely, thank you. And there are no PEs in my area
who do the kind of work I do (machine design and analysis) (yes, I have
checked). The PEs in my area mostly lay out septic lines and so forth.
Some have pointed out that we'd be alarmed to find out that the guy with
the rubber gloves we call "Doctor" wasn't a doctor. But what makes him 
one? His training and experience or the stamp of approval of the state?
The Wright brothers were the first Aeronautical Engineers, but no state
agency told them they could do that, and most would have told them that
the very persuit they were engaged in proved they were incompetent.
I'm not afraid of a test. I'm not legally allowed to take the EIT, let alone 
the PE exam in Montana.
Yes, PE registration would be nice, were it possible. I would be the same
engineer I am now, but at least a customer I had never worked with would
have some confidence that I won't get him buried in lawsuits or body parts.
My only complaint is that the registration process has too many barriers
that have nothing to do with the quality of my work, and everything to do 
with who I might compete with.
Marty Albini

John S. Novak, III (Jsn@cris.com) wrote:

: > The legislation also 
: >provides a uniform method of evaluating the experience. 
: I generally snort at the idea of uniform methods of evaluating
: engineering experience, knowledge, or ability.
Why?
--
*******************************************************************************
*                                                                             *
* Bernhard Michael Jatzeck         email:  jatzeck@fn1.freenet.edmonton.ab.ca *
*                                                                             *
*******************************************************************************

carl@voicenet.com (Carl Kirchner) wrote:
>Patrick Campbell  wrote:
>>Does anyone know about temperatue control of injection molding machines?
>>I need to know how accurate the temperature needs to be. +/- X deg C.
>It depends on what temperature you are talking about.  Do you mean
>the mold temp, melt temp, barrel temp, hydraulic oil etc?
Hello,
Good point.
For mold temp, if using a water or oil circulator that unit should be
no worse than +/- 2 deg F.
Barrel temp should be +/- 2 deg, with the exception of the feed zone,
that may run a little wider range.
I haven't done enough measurement to give a good estimate for melt
temp, plus you must have the proper setup to do it correctly.  
Hydraulic oil should be +/- 5 Deg F.  It does make a difference in how
your machine performs, with cold oil your machine operation will be
sluggish.
Hot runner temps should be +/- 1 deg or better.
This is tyipical of what a good molding machine can provide.  This
information is taken from the machine controls, without an independant
monitoring program, which may indicate the machine was not performing
quite this well.  
All temps that affect the plastic will be based on the plastic
processed.
Regards,
Sam
**************************************************************
Sam Underwood                         ** Professional Internet
619-945-9310                          ** Marketing and 
   ** Development for 
e-mail samu@internet-business.com     ** your Business
**************************************************************

Bob Falkiner  wrote:
>Under different provisions of state and federal law, engineers have
>various duties and obligations to the general public, the same as
>doctors, dentists, lawyers and other professions that are bound to
>uphold the public trust.  The requirements that you refer to are sound
>and justified. You would be some pissed off to find out that your doctor
>really wasn't one!
Yes, but at least in my state, a person who spent his internship and
his whole professional career as an ob/gyn can suddenly realize that
neurologists make more money and start to advertise and practice as a
neurologist. That's according to an ob/gyn I'm acquainted with. I
haven't researched the state law sufficiently to verify it. On the
other hand, state engineering law specifies that, by signing a design
as a P.E., I self-certify that I have the relevant experience and
knowledge to make the judgments necessary to approve that design. As
so many others have said in so many ways, that depends heavily on my
won honesty and realistic evaluation of my own competencies.
To address another issue, I DO make mistakes, even with that P.E.
after my name. However, knowing that I myself, not my employer or
anyone else, am personally liable for my mistakes whenever I use the
P.E. after my name strongly encourages me to be more careful and, yes,
more conservative, when I do. I think that is the intent of
registration, although in some places it may have degraded into a way
to charge fees to keep another bureaucracy alive.
=============================
Steven Estergreen, MSME, PE
Mulino, OR
slester@molalla.net
PP,ASEL,Instrument,Tailwheel,Complex
My employers don't pay for my Internet account 
and I don't care WHAT they think of the opinions 
I express here!

Give the silicones (RTV and 2-parts) a try -- there are many of these that
are better adhesives than the hardware store variety of "bathroom
caulk".  Often the silicones work well where there are big differences
in thermal expansion characteristics.
- Doug Milliken
On 17 Oct 1996, Peter C Brust wrote:
> I'm looking for suggestions on how best to join a Neodymium-Iron-Boron
> magnet to a HDPE plastic part.  The magnet is nickel plated, approximately

friction was and still is an area of science where there are very fine
lines between exact and approximate definitions....u (mu) the coefficient
of friction, is kinda a combination of factors all bunched together into
one variable...namely u (mu)....it combines material type, surface type,
contact and the like...that is why in calculating the u (mu) physical
experimental results have to be carried out, it is more of an empirical
science, we can only have an approx. estimates of it...furthermore people
may argue that friction is dependent on temperature, and some argue it's
not....that debate is ongoing....
dan
TriMech  wrote in article
<54bsm1$pv0@newsbf02.news.aol.com>...
> 
> One that's always puzzled me.
> 
> In school they taught us that frictional forces are governed by F=uN. 
> Now, u as I was also told in school is a property of the materials
> involved in the sliding.  Now what's thrown me is that there is no
mention
> anywhere of surface area, yet intuitively, a sled is going to slide
easier
> than a flat sheet of steel.  
> 
> Are my intuitions wrong or was I misinformed in school?
> 
> By the way, REAL bicycle spokes aren't tangential to the hubs anymore!
> 
> Paul Gimbel
> Mechie (and amateur triathlete)
> Tri-Mech Solutions, Inc.
> 

Hi there all. This is Australia here.  Does anyone know where I can get a 
comprehensive list that compares different sandwich composites?  We're 
building a vertical axis wind turbine and want to compare what's available, 
especially the prices. Any leads would be much appreciated.   

I remember a manwho thought he was an engineer. Had no patience with design
or maintenance engineering. He decided he could make a barge unloading rig
from two similar looking ones. He didn't know about calculating
counterbalancing properly. One man was crushed to death. (Company and date
by Email for the sceptical.)
I worked my way through engineering school by diving. My final career
decision had to be made at the time the North Sea opened up. It was an
interesting time - wide scale saturation diving, tons of new technology,
and high rates of pay. There were no porfessional qualifications for divers
and tenders (means life support technicians). Casualties were quite high
and included some of my friends. Most of them were preventable, if
reasonable decisions had been made.  (I stayed with DuPont at ordinary
pay.)
There are thousands of examples - remember why Challenger went down? - some
twit thought that Oring sealing could be determined administratively, made
an engineering decision on a "political" basis.
Where professional qualifications have been appropriate (doctor, engineer
etc.) and have not been in place we have paid with blood, ecological
disaster or ruined lives.
OTOH porfessional societies have tried to limit access to the professions,
bar the door to competent outsiders and keep the price up. This needs to be
controlled but not at the expense of public safety.

--
Peter Skelton
Skelton & Associates
613/634-0230
pgs@adan.kingston.net

homer@ccinet.ab.ca wrote...
>I disagree with Greg Jackson. The public should be protected thru 
>legislation from people who have not qualified as a Professional 
>Engineer by the way of provincial (Canada) laws. People with a Phd and 
>umpteen years experience can still make mistakes. 
I agree, because I fall into all three of those categories.  :-)
So.  How would having a PE change me?  Somebody wave a magic
wand when I finish the test and tell me I won't make any more mistakes?
Or will they just tell me I can now be sued when I make them?
>The legislation also provides a uniform method of evaluating the 
>experience. 
To whom?  Employers are not paying attention, or there wouldn't
be a perceived need for an industrial exemption.  Who else matters?
>That evaluation, along with the educational and character reference 
>will determine if that person should be licensed to use the title 
>Professional Engineer and practice engineering. 
To this statement I say, the evaluation is based on a test, though
rigorous, may not actually reflect what the engineer *will do in the
field*.  The educational and character references, especially the
latter, are so subjective as to be little better than random selection,
no matter how glowing the reports.
>Lets face it. Engineers build things that can threaten the lives of 
>people (cars, bridges, space shuttles etc). That work must be regulated.
How would you propose the building of space shuttles be regulated
over and above the systems currently in place?  *That* would be 
interesting.
Dr. Ron Graham
Project Engineer for Robotics, GreyPilgrim LLC, Washington DC
founder of sci.engr, editor of FAQ on Licensing and the EIT Exam
EMMA Robotic Manipulator now online - http://www.greypilgrim.com/

Need ENGLISH to SPANISH Technical Translators
One of our largest clients, BECHTEL, is sending over 1,000 pages in start-up
procedures for their South American electric power plant to our offices for
translation.   
Although we have a strong Spanish-English department, we are
in serious need of experienced and reliable English-Spanish Technical
Translators to cover this job and others.   The volume is huge, and we are a
fair and honest company.  We have had outstanding success finding
professional, qualified translators via internet.  Some have made $10,000 
per year with us.   
If you are a professional technical translator, native Spanish speaker,
properly qualified and experienced, we would like to offer you a substantial
amount of work.  
Our clients include:  GTE, CNN, Rolls Royce, Mitsubishi, Bechtel, Southern 
Company, Lockwood Greene Engineering, and many more.     
Thank you very much for your interest.  
	S.E. Reager
	President 
	International Services.  
Respond by internet to:
	SEReager@aol.com 
or fax resume to:  
	(770) 414-6555. 
-- 
Chris J. Scholz			School of Electrical and Computer Engineering
Georgia Institute of Technology
Atlanta, GA 30332		gt6900a@cad.gatech.edu

Can someone post the original question about tire noise? It seems to have
disappeared from my server...
Thanks.
Diana
-- 
Diana J. Hellman		 
hellmand@spot.colorado.edu	 Don't forget to stop and eat the roses.
(h) 303-444-2353
(w) 303-492-2523

Faleel N Mohideen wrote:
> 
> Hi,
> 
> I am posting an article that my friend has emailed me
> for possible answers. He does not have access to the
> Newsgroups. Will appreciate it if you could address your
> answers to his email address   MMM@rect.ernet.in
> Thanks
> 
> -Faleel
> 
> -------------------------------------------------------------
> Problem:
> 
> It is a balance holding equal weights on its two panes.
> This position is stable because either sides the moments are
> equal.
> 
>        _________________________
>         |         /\         |
>         |                    |
>         |                    |
>         |                    |
>      W  |                  W |
>       ~~~~~~              ~~~~~~~
>         <--- L --->|<--- L -->
> 
>
Stable is not equilibrium!
It means that when you disturb a system in equilibrium by a small
amount,
the system will restore to its original position.
Your second drawing is such an (exaggerated) disturbation.
Will the system restore to its original state? Depends on the exact 
location of the bearing (friction?) in the horizontal beam.
-- 
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
+ Gerald Wisse                                                    +
+ TUD, WbMT, Technische Mechanica    ++ 31 (0)15 2782702  Phone   +
+ Mekelweg 2                         ++ 31 (0)15 2782150  Fax     +
+ 2628 CD Delft                  G.Wisse@wbmt.tudelft.nl  e-mail  +
+ The Netherlands  http://www-tm.wbmt.tudelft.nl/~wbtmwis/  WWW   +
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
-- 
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
+ Gerald Wisse                                                    +
+ TUD, WbMT, Technische Mechanica    ++ 31 (0)15 2782702  Phone   +
+ Mekelweg 2                         ++ 31 (0)15 2782150  Fax     +
+ 2628 CD Delft                  G.Wisse@wbmt.tudelft.nl  e-mail  +
+ The Netherlands  http://www-tm.wbmt.tudelft.nl/~wbtmwis/  WWW   +
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++

Troy Savoie wrote:
> 
> I am looking for information on control strategies for a coupled
> engine/generator subsystem (on a DC bus - trying to control the DC current
> output of the subsystem).  If anyone has any information on this subject or
> could point me in the direction of good references (texts, journal articles,
> etc), it would be greatly appreciated.
> 
> Thanks in advance,
> Troy Savoie
You may find someone at Lockheed Martin Control Systems, 600 Main St.,
Johnson City, NY 13790-1888, phone 607-770-3574.  They have a web site
at http://www.lmco.com/controlsystems/index.html
The contact given on the web site is Dan Hogan, Mgr. Marketing
Communications, e-mail dan.hogan@den.mmc.com
Good luck,
Jim Baker

pavan1@student.monash.edu.au (Paul van den Bergen) wrote:
>I feel it is my duty to warn everyone that there is an
>international consortium of powerful people who get   
>together and facilitate the distribution of conspiracy
>theories in order to keep the minds of the masses off 
>the real issues that are affecting the world (whatever
>they may be...)
Ah,  words to live by!!!
I once pilotted a train...
Does that make me less of an engineer than you P.E.'s?
Dennis M. Barton, Jr.
Machinist by vocation...
Designer/inventor at heart!!
By the way,  I've never met an engineer who couldn't screw-up the
simplest design!!!!!

pgs@adan.kingston.net (Peter Skelton) wrote...
>There are thousands of examples - remember why Challenger went 
>down? - some twit thought that Oring sealing could be determined 
>administratively, made an engineering decision on a "political" basis.
Sigh.  No, Peter, this statement is incorrect.  I recommend you go back
and review the Rogers Commission report on the Challenger failure, and
to take a look at Vaughan, _The Challenger Launch Decision_, and 
have this mythology corrected.
>Where professional qualifications have been appropriate (doctor, 
>engineer etc.) and have not been in place we have paid with blood, 
>ecological disaster or ruined lives.
Many of the great failures of history fall on the shoulders of unexplored
new knowledge -- having PEs in place at the time (if it even were 
possible) would be unlikely to have changed that.
Dr. Ron Graham
Project Engineer for Robotics, GreyPilgrim LLC, Washington DC
founder of sci.engr, editor of the sci.engr.* FAQ on Failures
EMMA Robotic Manipulator now online - http://www.greypilgrim.com/

In article <5475g6$ifb@james.freenet.hamilton.on.ca>,
ad026@james.freenet.hamilton.on.ca (Paul Ransom) wrote:
> > Back to the original question:  of course, if you assume that the two
> > sections are *not* tied together solidly, and slippage occurs at the section
> > joint, then the two piles bend *indepentantly*, and thus act precisely like
> > they did before joining.
> 
> Not quite. If the two pile are similarly oriented, then they will
> generally act as you describe since they will both deflect similarly and
> there will be no longitudinal shear across the joint.
> 
> However, if the piles are alternately reversed;
> 1) each one independently may have different bending characteristics in
> positive and negative flexure and,
> 2) they will definitely not share a similar neutral axis with adjacent
> piles.
----------------------------------------------------------------------------
Paul:
I agree totally with what you stated above. My problem now is knowing
whether a sheet pile behaves differently in positive and negative flexure.
If the classic beam theory is applied, thus assimilating the sheet pile to
a beam, then their behaviour should be exactly the same (I'm thinking in
terms of small deformations). I think in standard practice this hypothesis
is made. 
About the neutral axis, I agree as well, but what would the consequences
of that be?
There was an excellent response to this posting by Mr. Andrew Moskalik
which has mysteriously disappeared. I think it might add some good ideas
to this discussion if it was put up again.
Thanks,
-- 
Enrique Juaristi, mechanical engineer

Dick Brewster wrote:
> 
> John P. Becker wrote:
> >
> > If you are a real engineer, you are a Professional Engineer.
> >
> > John Becker, P.E.
> 
> A P.E is just another indication that a person has met certain
> standards. It is not; however, a very good indication of a perons
> ability to engineer.  Any twit who has graduated from an acredited
> engineering school should have no trouble getting his/her P.E. ticket
> punched if they go to a little effort.
> 
> Dick Brewster, P.E
Well, Dick, I've known many a twit that met the minimum requirements for
sitting for the exam that failed.  Some as many as three to five times,
before passing.  These people put in some substantial effort.
Twittage aside, I've also known some nondegreed people that didn't come
close to fulfilling the requirements to even sit for the exam that were
better engineers than others that passed the same. I've known others
with degrees that didn't meet some of the requirements that were also
excellent engineers and much better than some that were "PEdigreed." 
I've known one engineer in that last group to challenge the licensing
board and forced them to allow him to sit for the exam and he passed.
You're right that a PE license only shows a minimum level of competence,
but that's the point.  Licensing is intended to protect the public from
the unscrupulous and unqualified, but has also become something of an
elitist club.  I've read arguments that stated that professionals of any
kind shouldn't require licensing at all and that market forces should
drive professionals to licensing, not legislation.  Except that it cuts
into my livelihood and that there are many unscrupulous persons in the
world, they could be right.
It's also right that gaining a PE license places engineers in a somewhat
elite group, simply because there are many twits in the field that can't
cut it.  But, licensing hasn't kept the unscrupulous or incompetent from
practicing in the engineering disciplines.  The report the State of
California's licensing board puts out annually mentions several
engineers that do unethical things incompetent acts, and details their
acts and "punishment" for them.  There are certainly more that aren't
caught or pursued.
The name of the game is money and who's going to pocket it.  I prefer my
pockets.
Peter L. Tarver, P.E.

try:  sci.engr.metallurgy or alt.recreational.mining or sci.engr.mining
for  more repsonse.
In article <54800h$85d@purple.iap.net.au>, pd05831@gold.iap.net.au 
says...
>
>        
>Are there any Knelson  C.D. Concentrator users  around ?????
>
>Have you any bitches, queries, questions and all that, please contact
>me and i will try to satisfy your problems.
>
>If I can't help you please send me your query and I will throw it
>around our group to discuss.....
>
>Regards
>Steve HULL
>Kalgoorlie
>Western Australia.
>

On Wed, 16 Oct 1996, B.F. Lundy wrote:
 	I am working on a zero-g flow boiling experiment involving a 
  counterflow vertical annulus comprising a test fluid in the central 
  annulus with a heating fluid in the outer annulus. The test fluid is 
  undergoing a phase change, and I need an accurate way to predict the 
  minimum tube diameter needed to avoid cappillary bubble flow.  My current 
  method involves a force balance on a hemispherical meniscus in the tube.  
  I'm sure there are better ways of predicting this phenomena.  I have 
  several different fluids under consideration, each with vastly different 
  surface tensions.
  Thank you,
  B.F. Lundy
  Texas A&M; University

This licensing garbage is just another money-making scheme for
the Government and academia.
Let my degree and my abilities speak for themselves.
trl2371@aol.com

Hi All,
I am working with disabled population and was looking 
at using an "air-bearing" to gather some data.  I have 
seen air-bearings used on shop floors, aircraft industries etc
to move heavy loads on the principle of hydroplaning (this
is my understanding).  
I understand that you create enough air pressure so that
the load is supported.  
Now to my question:
1. Are there any manufacturers that make these for really
small loads like 5lbs.  ( I guess it sounds like why would
one need an air bearing for this small load - I gathered
for some of the people I called).
2. Any pointers to the theory behind these so that I may
be able to make my own for this specific experiment.
Thanks for any pointers, help and comments and thanks
for your time.
rungun
-- 
====================================================================
           \__   ____      \__  |Name   : Ranganathan Ramanathan
 /__  /  / /  \ /___/ /  / /  \ |S-Mail : ASEL, AI DuPont Institute
/    /__/ /   / ___/ /__/ /   / |         PO Box 269, Wilmington
ramanath@asel.udel.edu          |         DE 19899
sg92di9e@dunx1.ocs.drexel.edu   |Phone  : 1-302-651-6869;1-215-895-2376
WWW Home Page : http://www.asel.udel.edu/~ramanath/index.html
====================================================================

Position announcement:
Our client is in need of a Manufacturing Engineer with experience i basic 
Mechanical engineering; machining (cutting process, CNC machine tools, 
cutting tools, jigs and fixtures, CNC/PLC programming, and quality 
control.
the candidate must have 3-5 years experience in CNC machining as an 
engineer.
Call Leo Oberto
     Capitol Search Group
     757-471-9439
     leoo@pop.erols.com

Mr. Barton, Jr. wrote:
>By the way,  I've never met an engineer who couldn't screw-up the
>simplest design!!!!!
Amen, to that one !!!!!
Ken Shearron
Machinist

In article <548dbo$4ns@netnews.upenn.edu>, jeffe@blue.seas.upenn.edu (george) writes:
> :
> :The ones for fifth and sixth don't exist, that's been proven.  The ones 
> :for third and fourth are awfully complex.
> 
> third's actually not so bad.
> 
> Courtesy mathematica:
> Solve[ a x^3 + b x^2 + c x + d,x]
> 
> A=(3*a*c - b^2)
> D=4*A^3 + (-2*b^3 + 9*a*b*c - 27*a^2*d)^2
> B= (sqrt(D) -2*b^3 + 9*a*b*c - 27*a^2*d  )^(1/3)
> 
> If D>0 there is one real root:
> 
> x = -b/(3*a) - (2^(1/3)*A)/(3*a*B)  +  B/(3*2^(1/3)*a)
> 
> 
> with similar expressions for the complex roots.
> 
> for fourth order, each root takes up a good part of a page..
> 
> 
> 
> -- 
> george 	
> george@mech.seas.upenn.edu
> 
Determinate solutions to the cubic and quartic equation are given in "Handbook 
of Applied Mathematica for Engineers and Scientists", Max Kurtz, McGraw=Hill, 
1991, p. 1.31 to 1.41.  A fortan routine is even given to solve for the roots of
a cubic equation.  A quartic is resolved into the roots of 2 quadratic
equations.   All of the above assume real numbers for the coefficients in the
polynomial.
  Jerry

Sir Spamalot wrote:
> 
> >On Wed, 16 Oct 1996 13:03:52 -0700, Mike  wrote:
> 
> >> The reason to install them is the following:
> >>
> >> Mechanical vibrations, especially in helicopters, causes the pilot's
> >> eye-balls to oscillate. This makes it impossible for the pilot to see
> >> the cables between the pylons.
> >>
> >>ttp://www.alcatel.com/
> >
> >Ha! Vibrating pilot eyeballs!  Without the elephant balls, those suckers
> >are invisible at noon from a balloon.
> >
> 
> Maybe this is all true, but what the hell are the pilots doing
> flying so close to high tension wires?
> 
> And why are they called "high tension" when the wires are
> obviously under little tension??
They would be close to the wires if they could see the balls on RADAR 
etc.
I'm sure you know what high tension means but just in case (experts - 
don't jump on me for imprecision!) tension is synonymous with potential 
and voltage in this context - don't ask me why there are so many 
different terms for the same thing.
Nice to see something a little light hearted on seec for a change even if 
it strays a little beyond our normal limits :-)

I am working on a FEA of a simple rectangle modified by radii on the sides
(for ex. a .5" high by 3" long rubber with a .5" radius into each side).
Though the radii are not very deep into the material, I still get 
singularities at the very top right corner for a displacement in the x 
direction. I am using PLANE83 and when I increase the mesh (i.e. reduce 
element size) the stresses increase in this area. Is there a way to 
remove this singularity from the analysis? Someone mentioned adding a 
spring somehow but I'm not sure how/where. Any pointers? I'm using ANSYS 
by the way.
Leslie
--
_____________________________________
Leslie P. Fowler
fowler@mpd.lord.com
_____________________________________

Will's example of how it changes on the micro scale is particularly true in
the example in the original post.  The high normal force on a sled runner
usually results in a thin film of water being created underneath it,
thereby changing u from steel-on-snow to steel-on-water.
This effect does not exist when you drag a sled on asphalt for example, and
you would end up with the same frictional force as the sheet of steel.
-- 
Mark Wright, PE
SCIMED Life Systems
A Division of Boston Scientific Corp.
William Gardner  wrote in article
<54ds4m$5hs@news-e2c.gnn.com>...
> 
> In article <54bsm1$pv0@newsbf02.news.aol.com> TriMech wrote:
> >One that's always puzzled me.
> >
> >In school they taught us that frictional forces are governed by F=uN. 
> >Now, u as I was also told in school is a property of the materials
> >involved in the sliding.  Now what's thrown me is that there is no
mention
> >anywhere of surface area, yet intuitively, a sled is going to slide
easier
> >than a flat sheet of steel.  
> >
> >Are my intuitions wrong or was I misinformed in school?
> 
> On the macroscopic scale, fricitional force is not dependent on surface
area. 
>  However, on the microscopic scale, as normal force is increased, the
actual 
> contacting surface area is increased approximately linearly, hence the
linear 
> F=uN relationship.  There was an excellent article in the last Scientific
> American on this exact topic.

In article <325FF3A9.4919@mt.net.au>, Stephen Walker  wrote:
> I have heard that someone in the USA is making ceramic apex seals to suit 
> mazda rotary engines. These seals have twin apex seal springs , and 
> apparently last much longer than carbon seals. Any info would be 
> appreciated . Please EMAIL me at smat@mt.net.au
> Thanks
> Stephen Walker
You might get more response if you post this in rec.autos.tech or
rec.autos.sport.tech
Rob

I digress further....
If a company hires some schmuck that faked his 'Engineer' title, they had
it
coming.  A little research could have prevented it.  The P.E. title is, in
my 
opinion, nothing more than resume fodder.
Tom Larson
Mechanical Engineer

But isn't it still possible that these wires are actually called "high
tension" because of the high tension required to string them?  The tower
structures are usually spaced quite far apart and are carrying quite a
number of large diameter copper cables.  I would think they would have to
tension the crap out of those things just to get them strung from tower to
tower.
Think about stringing a light cage TV cable all the way across your yard. 
You have to pull quite hard and still have a pretty good droop.
-- 
Mark Wright, PE
SCIMED Life Systems
A Division of Boston Scientific Corp.
gordon telling <101356.2265@compuserve.com> wrote in article 
[snip]
> > And why are they called "high tension" when the wires are
> > obviously under little tension??
[snip]
> I'm sure you know what high tension means but just in case (experts - 
> don't jump on me for imprecision!) tension is synonymous with potential 
> and voltage in this context - don't ask me why there are so many 
> different terms for the same thing.

In <54ccr9$jam@news.sas.ab.ca>, jatzeck@freenet.edmonton.ab.ca () writes:
>dano@cyberramp.net wrote:
>: This doesn't mean I'm *for* engineers without PEs lying about their abilities,
>: it means I don't see how getting a PEs makes a dishonest engineer an honest
>: one.
>
>That's one reason why, in Canada, one cannot practice professinal 
>engineering in a province without being registered with the respective 
>provincial association.  If nothing else, the discipline committees weed 
>out those who are dishonest or unqualified.
Still, I wonder why specifically the _Professional Engineer_ certification is
needed.  Why not give every engineering graduate an "I graduated with an
engineering degree" certificate, which is required to legally work, and which
can be revoked if there is caught dishonesty?  I don't mind weeding out 
crooks, I just don't see why the PE is necessary.
And to deflect criticism on one point, perhaps every current engineer can
be grandfathered, and those w/o degrees but with experience need to 
'document' their work to get certified.
>* Bernhard Michael Jatzeck         email:  jatzeck@fn1.freenet.edmonton.ab.ca *
---
      program signature
      write(*,*), 'Dan Stephenson'
      write(*,*), 'dano@cyberramp.net'
      stop
      end 

                     MATHEMATICAL SCIENCES DEPARTMENT HEAD
Worcester Polytechnic Institute (WPI) is an innovative technological
university in engineering, science, management, humanities, arts and
social sciences with an enrollment of 2,500 undergraduate and 400
full-time graduate students, located in central Massachusetts. 
The WPI Mathematical Sciences Department, currently with 22 full time faculty, 
provides undergraduate and graduate education through the doctoral level.  
Active areas of faculty research include applied mathematics, optimal control, 
stochastic processes, statistics, operations research, discrete mathematics, 
scientific computation and mathematics education.  The department has an
expanding industrial partnership projects program and has been in the
national forefront in educational innovations.  Its support facilities include 
state of the art research computers and networked workstation laboratories. 
For more information see http://www.wpi.edu/Academics/Depts/Math/.
WPI seeks a dynamic individual who can promote growth in the department's 
internationally recognized research program by personal participation and by 
attracting several outstanding faculty to fill anticipated openings.  
Applicants must have a strong international research reputation.  The new
department head will be expected to take a leadership role in educational
innovation.  He/she will have the opportunity to expand and develop new
research activities, educational programs, and cooperation with industry.
The beginning date for the appointment will be July 1, 1997.
Nominations for and applications from persons holding a Ph.D. should 
be directed to the 
Mathematical Sciences Department Head Search Committee,
Dept. E , Office of Human Resources, 
Worcester Polytechnic Institute, 
100 Institute Road, Worcester, MA  01609-2280 
or
email human-resources@wpi.edu .  
To enrich education through diversity, WPI is an affirmative action, 
equal opportunity employer.

RonGraham1 wrote:
> >Lets face it. Engineers build things that can threaten the lives of
> >people (cars, bridges, space shuttles etc). That work must be regulated.
> 
> How would you propose the building of space shuttles be regulated
> over and above the systems currently in place?  *That* would be
> interesting.
> 
> Dr. Ron Graham
> Project Engineer for Robotics, GreyPilgrim LLC, Washington DC
> founder of sci.engr, editor of FAQ on Licensing and the EIT Exam
> EMMA Robotic Manipulator now online - http://www.greypilgrim.com/
I was taught that the strength of a bolt is 99% dependent (exageration
for dramatic effect) upon the high-school drop-out that tightens it. 
These are the same guys fixing/building our cars, bridges, etc.  I have
looked all around, I don't see any regulation there.
I think I have figured out why there is no certification required for
pragmatists.
Good to hear your opinion.
Dave Lawson
Mechanical Designer

What a lively discussion!  I'd like to add my own two bits.  I am an 
industrial hygienist married to an environmental engineer (EIT).  As one 
article mentioned earlier, the profession of industrial hygiene is 
undergoing a similar title protection debate, but, from what I've seen, 
either all IH's agree with title protection, or they're too busy to 
complain.  Here are three major drawbacks, as I see them:
1-Although most of you would be unaffected by this, title protection is 
*very* discriminatory against young professionals.  I suppose from your 
perspective, this is the point and even the goal of title protection.  As 
I see it, even after investing years at college and internships, I won't 
be "qualified" to run a sampling pump because I'm not a CIH; and the only 
way I'll ever be a CIH is to get 5 years of professional experience; but 
I'll have a *tough* time getting 5 years of experience because companies 
want to hire only certified industrial hygienists!!  Didn't folks in your 
generation call this a catch 22?  I won't pretend that I have the 
expertise of someone with years of experience and a CIH.  But one of the 
reasons I chose industrial hygiene over medical school was that I 
wouldn't have to wait to turn 30 before I could work professionally.  Any 
company who hires an industrial hygienist or an engineer should check 
credentials.  Buyer beware!
2-Many of these laws require liscensing in *each state*.  What will this 
do to consultants?  If a consultant wanted to think about accepting jobs 
in any given state some day, he would have to maintain that state's 
certification.  Small consulting firms that service several states would 
quickly be driven out of business because of the cost of holding down 
redundant titles in several states.  My father is a pharmacist and sees 
this as a major problem in his profession.
3-Many employers don't understand anyway.  I've seen several ads for IH's 
that state "One year of experience *and* certification required."  You 
can't get certified with only one year of experience.  I don't think this 
ignorance will change with the passage of title protection.  You can tell 
which ads are placed by companies with no idea what they really need.  
And if some idiot lies about being certified to one of these companies, 
who is going to know?  Title protection laws don't educate these 
companies on what level of expertise is necessary to perform certain 
tasks.
This is all just my opinion.  To all of you who are certified in your 
respective professions, I admire the work that went into obtaining and 
maintaining that certification.  I recognize your expertise.  But I'm not 
useless just because I'm only 24.  I am responsible for the health and 
safety of around 2500 people and I'm smart enough to ask for help from 
more experienced people when I need it.  Weren't you able to get a 
professional position out of college?  Why change the rules now?
--Kris  (the opinions expressed here are strictly my own and do not 
necessarily reflect my company's position)

PANI CHAKRAPANI wrote:
> 
> We are looking for software to do Rainflow fatigue analysis from strain
> gauge input to HP-Vee data aquistion.
> 
> Does anybody have a suggestion?
> We don't have a Fortran compiler.
> 
> Thanks in advance,
> 
> Ron Lansing
> 
> MEI-Charlton, Inc.
See the following article:
Downing, S. A., and D. F. Socie, "Simplified Rainflow Counting Algorithms," 
International Journal of Fatigue, 4:1, 31-40, 1982. 
Downing and Socie also sell fatigue analysis software (including rainflow counting) 
through their company Somat, as well as hardware and interfaces.  I couldn't find 
a website for Somat, but Socie's U. of Illinois page is 
http://www.mie.uiuc.edu/personnel/faculty/socie/socie.html.  His e-mail address 
is d-socie@uiuc.edu.
-- 
Robert W. Warke
Sr. Research Engineer
Edison Welding Institute
bob_warke@ewi.org

Felice Luftschein & Nicholas Carter wrote:
> 
> The jewelry made for body piercing (eek!) is constructed out of
> 316L stainless, not 316, as the consensus is that 316L is more corrosion
> resistant. My materials book says that L series are for welding, so is this
> true, or is the corrosion resistance of the two (316 and 316L) the same?
> 
> Also, does anyone know of a good source for 316L wire in 00 to 18 gauge?
> (I'm going to cash in on the most stupid trend of the 90's!)
The 316L is a low carbon variation of 316.  Carbon precipitation at
welds causes
316 to become MUCH less corrosion resistant.  If you are going to weld
your 316 
you should definately use 316L.  
I think you should have someone who knows their stuff help you with
this.  Body
piercing is not as trivial as it may seem to be.