Newsgroup sci.engr.mech 27845

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rwwaitt@aol.com (RWWaitt) wrote:
>As an engineer who has spent most of the past 22 years designing overhead
>transmission lines, some of which have included some sort of marking, I
>have read the recent string of posts with interest. A few notes:
Great post.  As a pilot I have seen these everywhere and find them
useful.  Chopper jockeys are especially grateful for them.
>5 - Lifetime
>
>Unless they are damaged by some external action (the line falling down,
>trees falling across the wire, or gunshot damage), fiberglass balls are
>permanent. Some of ours have been in service for 25 years or longer.
>
>One exception to this is an occasional, unpredictable experience of
>spontaneous burning of fiberglass balls which have been attached directly
>to the line conductors. The fiberglass itself burns and falls to the
>ground, and all that remains on the wire is some soot and the metal
>attachment hardware. (I would be very interested in discussing this with
>anyone who has had a similar experience.)
I KNOW the answer.  Martian snackfood.  

Yes. You touch on the important distinction between academic 
qualification (degrees) and vocational qualification (registration).
The mission of the academics is to advance and disseminate knowledge
of the art, the mission of the registrants is to practise the art in
a sound and beneficial manner.    Perhaps I should have written 
"the mission IMHO should be..." instead of "the mission is...".
You can do research and teaching and obtain degrees without being
registered. And, in California at least, you can become registered
without a degree (17 years documented on the job experience working
for an Engineer will do in lieu of an Engineering degree). It will
surprise no-one that most undegreed registered Engineers are elderly!
Its a case of horses for courses, but I do think the Universities
would serve society better if they were to do more to encourage
Engineering students and faculty to prepare for and seek registration.
California used to offer an E-I-T waiver for Engineering faculty,
however this complicated comity negotiations.
Henry Black P.E. (Calif.)
Bill Sprague (bsprague@redrose.net) wrote:
: >snip..snip<
: I think the reason for the lack of emphasis on the EIT is that most University 
: professors of engineering are PHD's not PE's.  If they were practicing 
: engineers they'd know to encourage their students to take the EIT in their 
: senior year.  I'm a PE and PLS with a masters in CE but I cannot qualify to 
: teach engineering anywhere.  Conversely, a BCSE can in four years qualify to 
: perform the structural engineering necessary to keep the roof from falling in 
: on the university's engineering building.  Did you ever ask if universities 
: design their own building?  They don't....thay want experience and 
: the responsibility ( read - liability) of a PE not a PHD.

:
:Mark's Standard Handbook for ME's, 8th ed., states that the coefficient
:of friction will get larger as the temperature falls and cites data from
:Bowden for brass on ice which shows that as temperature falls from 0 deg
:C to -60 deg C, friction coeff. goes from 0.025 to 0.14.  This would
:explain the reason why it is easier to drive on ice when it's really
:cold.
I have to cringe at the use of "coefficient of friction" applied
to ice..  You'd get very different numbers if you
looked at an ice skate, vs looking at a plate with a large
area.  Actually, I expect the numbers should be vastly different
near 0C and converge as you lower the temp..
-- 
george 	
george@mech.seas.upenn.edu

etk12573@rpool14.rus.uni-stuttgart.de (Frank Wuest) wrote:
>The German equivalent for tension as synonym for pressure when
>referring to hydraulics ? I never heard it used this way.
>
>It is quite clear to me that both tension AND voltage are 
>translated as "Spannung" (I AM German), which seems to be similar in
>French where these words are translated as "tension".
>
>What might bug you in German is the word "Starkstrom"
>Translated literally, it would mean 'strong current', but it
>is actually used to refer to installations or cables of high
>power handling capacities...
>
I stand corrected.
What I said was however based on the previous post (Gerhild
Kirchweger) presumably German, and the fact that the drawings and
documentation for a second hand German built machine we are currently
installing, persistantly refers to the hydraulic pressure as 'Tension
Hydraulik.'
Rgds
Ian Fitter
Warrington, Cheshire                                    (UK)
------------------------------------------------------------
ianf@icf.u-net.com              idfitter@cix.compulink.co.uk
IDFitter@iee.org                   http://www.u-net.com/~icf

Have you thought of using high pressure water cutting.  I removed a vessel 
that had a 1/2" thick steel plate, 1/4" rubber lining, 8" thick brick lining 
and hard calcium deposits.  The water jet also include some granite for better 
cutting.  It worked really well, but it was sometimes a slow process.
Steve Sternberg
J. R. Simplot Co.

WHAT!!?? I can't call myself a mining engineer????
I'm a mining engineer, accredited university, no EIT, no PE.  Course
work related to underground coal mining.   No surface mining, no
environmental classes, minimal geology.  Been working in surface mining
for 20 years and never have done any of the stuff that's on the mining
PE test. So gee, if I was registered, I couldn't in good conscience sign
for anything anyway!!!! 
What do I do?  I'm a Mining Engineer specializing in blasting at surface
mines.  What does this entail?  Civil engineering, seismology and
structural engineering.  The civil engineers won't have me because I
don't have civil BS (oops I mean a BSCE).  The geologists won't have me
because I don't have a BS in geology.  
Its bunk that I can't call my self an ENGINEER!!
PS.  My office mate is a geologist with no computer training.  Does that
mean he shouldn't be our UNIX system administrator?

 The miller cycle is currently applied in the Mazda Millennia engine.
Jeff Schmidt

Hi... I'm an EIT with a question that is probably pretty simple, but I 
can't find any standards to refer to:
I have a pressure vessel (an air receiver) that is currently sitting 
horizontally on its supports (four "legs").  I have been asked if we can 
move this receiver such that it is "hung" on the wall by its legs (ie. it 
will be supported vertically).  In my limited experience, I've never seen 
one hung from a wall, and nor have others that I've spoken with at work.
Are there any regulations stating the support configuration for pressure 
vessels?  My main concern is the shear in the thin walls (4.6 mm / 0.181 
in) during the worst case scenerio that it is full of water.
Please copy your response to my e-mail address.
Thanks...
--
.............................................
Julie M. Thomson -- jthomson@ciao.trail.bc.ca

>>         I am wondering if anyone has any information on implementing a
>> truss analysis program on a PC. I am a final year mechanical engineering
 >
 >There are a number of files, both shareware and demonstration
 >versions, for programs of this nature in the MechEng Archive.
 >These can be found by any of the following URLs or other means:
 >
 >   ftp://ftp.mecheng.asme.org/pub             (root directory)
 >   ftp://ftp.mecheng.asme.org/pub/readme.1st  (general intro text)
 >   http://www.mecheng.asme.org                (web page)
I see a couple of files in the ASME archive with "truss" in the title, but
they are getting a little long in the tooth (5 years or so). Are there any
other, newer, graphical-oriented options out there...free, share or
commercial-ware? Thank you.
-- 
Miles Abernathy, miles@mail.utexas.edu, http://klingon.util.utexas.edu/

rklakakp@cc.curtin.edu.au wrote:
: Hello Engineering Bretheren,
:    The topic of gas powered refigerators has come
: up at work recentely. I'm refering to the old type
: of refigerators which _burned_ (yes that's right) gas
: (methane or whatever, I think some may have also worked
: on electrical resistance heating) to heat the working
: fluid which somehow cooled the inside of the refigerator.
:    Does anyone know how this cycle works? It has several
: of us stumped at the moment.
It's called absorption cooling and works on an endothermic reaction 
between two chemicals, in most cases, ammonia and water. The water and 
ammonia combine in the cooling coil where heat is absorbed -> ie 
absorption -> endothermic . The mixture then flows into a chamber where 
heat is supplied and drives the ammonia out of the water. The ammonia passes 
through a condensor where it returns to liquid and the two separated fluids 
can then combine again in the cooling coil.
Many commercial chillers are in service where heat energy is available 
throughout the year.
Try a search on absorption cooling for all the details.
GB

try NASA

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In article <326CC2A8.41C2@ornl.gov>, c4p@ornl.gov says...
>
>John S. Novak, III wrote:
>> 
>> I take a very dim view of standardized tests.
>
> John, if you have legitimate recommendations on how to make the P.E. exam
> fairer, please send them to the NCEES in Clemson, SC.  I'm sure they would 
> gladly listen to your concerns.
Maybe you're sure, but I think there's a significant group here that isn't so 
sure we all have the same objectives.
> Until then, let's hold off on the animal-like sounds.  The 
> nationally-standardized P.E. exam we have now - that all states will be
> administering in a few days - 
A hallowed event...
> is certainly better than no test at all.
>
> Perhaps one reason the P.E. exam doesn't seem fair to some people is that 
> they have become too specialized and have lost touch with what they learned 
> in college (or should have learned since).  Professional Engineers should 
> have and demonstrate a broad spectrum of engineering knowledge, and perhaps 
> that's what distinguishes them from the rest of the crowd.  JMHO.
Humility doesn't become one so distinguished from the crowd.
Are you saying that
     1) any engineer that couldn't sit down and dash off the PE exam is too 
specialized?  Gee, that's interesting:  I wonder how many of the PE's that took 
the exam, say, 15 years ago, would be able to do that today.  After all, since 
they're such well-rounded engineers, they should be up to speed on all aspects 
of common engineering practice.  If you have to study for the exam, then you 
don't know the subject.
or, 
     2) that, by demonstrating this breadth of capability once, a PE has so 
demonstrated for a lifetime?  Gee, maybe it's safer to hire _young_ PE's.
I don't see a logical alternative interpretation of what you wrote.
You seem not to understand that market forces drive engineers (and people in 
essentially every other human endeavor) to some level of specialization, and 
that this isn't a bad thing.  After all, when you want to develop a new gas 
turbine engine, you don't go to the yellow pages and look up PE's (and it's a 
good thing:  most G-T engineers are not PE's).
BTW, 14 years out of grad school, I suspect I would fare pretty well on the 
test today, yet I still don't believe in the process of using a standardized 
test as a ticket to calling onesself an engineer (restrictions from calling 
onesself a Licensed Professional Engineer would be fine).  The process is 
burdensome and, in the end, only "qualifies" one as basically competent.  Boy, 
I'd really like to hang that on my wall!
-Wayne
-- 
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 Dr. Wayne S. Hill                                    wshill@world.std.com
 Foster-Miller, Inc.           ***Disclaimed***           617-684-4228
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

M.E. Moore wrote:
> 
> AJ wrote:
> >
> > when you turn on the hot tap the water comes out at a high rate.
> >
> > after about 10sec it becomes a trickle.
> >
> > WHY?
> >
> 
> Good question.  It drives us crazy at home.
> 
> M.E. Moore
> Los Alamos, NM
In software termonology, "It's not a bug, it's a feature"
You know the shower is ready for you when you hear the water slow down.

In article , jthomson@ciao.trail.bc.ca (Paul
Chernikhowsky) wrote:
>I have been asked if we can 
>move this receiver such that it is "hung" on the wall by its legs 
It won't make any difference if it's supported as firmly to as stiff a
foundation as on the ground. I'd bet that it won't be, if for no other
reason than it'll be hung by the bolts which probably weren't designed for
it. The connections between the vessel and the legs will also be subject
to tension which may prove to be a fatigue problem. I think you'll also
have the tank drain opening no longer at the vessel low point, which makes
draining something of a chore. But you'll need to drain it anyway.
Oh yeah. Your main concern should be local bending in the wall of the
vessel at the legs. Shells don't respond well to that sort of thing. The
Welding Research Council has a couple of bulletins on how to figure
stresses due to local loading which should be checked. The ASME Code
doesn't deal with vessel supports explicitly because it's a difficult
problem.
Christopher Wright P.E.    |"They couldn't hit an elephant from
chrisw@skypoint.com        | this distance"   (last words of Gen.
___________________________| John Sedgwick, Spotsylvania 1864)
http://www.skypoint.com/subscribers/chrisw

In article <54n0k7$890@alpha8.curtin.edu.au>, rklakakp@cc.curtin.edu.au wrote:
> Hello Engineering Bretheren,
Works on the Ammonia absorbtion cycle.  Look up some refrigeration books
on this topic.  I always thought that this style of system would be great
for car air cond. by using a bypass arrangement on the exhaust system to
regulate the hot side.
Bill

>AJ wrote:
>> 
>> when you turn on the hot tap the water comes out at a high rate.
>> 
>> after about 10sec it becomes a trickle.
>> 
>> WHY?
The rubber washer that seals against the valve seat takes a set when the
valve is closed. When it's cracked open, it begins to relax, filling the void
left by the impression of the valve seat. This closes off the flow area 
somewhat. The same thing happens with cold water but slower, as the
relaxation happens faster at high temperatures. It's worse if you really 
crank the valve shut.
Marty Albini

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In article <326F8414.155D@eng.cam.ac.uk> Mark Thornton  writes:
>From: Mark Thornton 
>Subject: Questions about Zircalloy
>Date: Thu, 24 Oct 1996 15:58:28 +0100
>I have 2 questions:
>1) Are Zircalloy 2 and Zircalloy 4 the same as R60802 and R60804 in the
>American Unified Numbering System?
>2) Is Zircalloy a registered trademark? If so, who owns it?
>Thanks in advance for all help received,
>Mark
>-- 
>Mark Thornton                           Tel: +44 1223 332760
>Cambridge University Eng. Dept.         Fax: +44 1223 332662
>Trumpington Street                      E-mail: mht11@eng.cam.ac.uk
>CAMBRIDGE CB2 1PZ, UK                   
>http://www2.eng.cam.ac.uk/~mht11/
Mark,
No, the're not the same. Comps as follows:
                60802                     60805
Cr          0.05 - 0.10                0.07 - 0.13
Fe          0.07 - 0.20                0.18 - 0.24
Ni          0.05 - 0.08                   <0.007
Si             <0.02                         <0.012
Sn          1.2 - 1.7                    1.2 - 1.7
Fe+Cr+Ni   
              0.18 - 0.38
Fe+Cr                                        0.28 - 0.37
I don't know if Zircalloy is a trademark, but would guess probably so.
regards
tim
usual thingys 

rklakakp@cc.curtin.edu.au wrote:
> 
> Hello Engineering Bretheren,
> 
>    The topic of gas powered refigerators has come
> up at work recentely. I'm refering to the old type
> of refigerators which _burned_ (yes that's right) gas
> (methane or whatever, I think some may have also worked
> on electrical resistance heating) to heat the working
> fluid which somehow cooled the inside of the refigerator.
> 
>    Does anyone know how this cycle works? It has several
> of us stumped at the moment.
> 
It is called absorption refrigeration, invented by a 
Frenchman Ferdinand Carre round 1860.
The absorption cycle is similar in certain respects to the 
vapour-compression cycle, but instead of using a compressor 
to transform the low-pressure vapour after the evaporator, 
the absorption system first aborbs the low-pressure vapour 
in an appropriate absorbing liquid.  Since this is like 
condensation, heat must be rejected.  The next step is to 
increase the pressure with a pump or using gravity on 
domestic units and then the vapour is released from the 
absorbing liquid by adding heat (this is usually the gas 
flame).  The absorbing liquid is throttled back to 
the absorbing unit and the high-pressure vapour gas 
to the condensor like the vapour-compression cycle.  Ammonia 
and water were commonly used, but has been surpassed by 
lithium bromide and water.
Just ask if you want more detail.
Tinus Keyser

Yan Seiner, PE wrote:
> 
> Software to my knowledge has never been the direct cause of a
>fatality.
I believe that a software bug in a CAT scanner caused a number of
fatalities.  I have heard this indirectly, and haven't been able to
confirm it, so it may be an "urban myth".
But the story is that due to a software bug, if the technician entered a
specific series of commands, the x-ray beam would be turned on and 
left on.  The results to the patient were obvious, but not immediately.
I think this kind of software bug is what people are afraid of when
considering that the software for the air-traffic control system
or for Star-Wars will be so complex that one could never prove
it was accurate.
What do you do if one can prove that the software can not be insured to
be correct?

Yan Seiner, PE wrote:
> 
> Software to my knowledge has never been the direct cause of a
>fatality.
I believe that a software bug in a CAT scanner caused a number of
fatalities.  I have heard this indirectly, and haven't been able to
confirm it, so it may be an "urban myth".
But the story is that due to a software bug, if the technician entered a
specific series of commands, the x-ray beam would be turned on and 
left on.  The results to the patient were obvious, but not immediately.
I think this kind of software bug is what people are afraid of when
considering that the software for the air-traffic control system
or for Star-Wars will be so complex that one could never prove
it was accurate.
What do you do if one can prove that the software can not be insured to
be correct?

I lost track of Tim Ellis after some developer bull-dozed the apartments
where he had established his permanent HQ.  He is a tall, athletic guy who
loves to jetski.  Please give him my email address.
Danny Oakes, PE BSME UF 1980
afn50752@afn.org

In article ,
ajmosk@engin.umich.edu (Andrew Moskalik) wrote:
> In Article ,
> enrique.juaristi@crpht.lu (Enrique Juaristi) wrote:
> 
> >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.
> 
> Why, thanks for the compliment.  I've actually made two posts, so I'll
> repost both (which makes this quite long, I'm afraid).  I've added a couple
> comments at the end of this article.  Here they are again:
(snip)
> Additionally, Ken Zagzebski, in another article, commented that the
> "twisting" effect would be much less pronounced (i. e., ignorable) if you're
> talking about a sheet pile *wall* (many piles) rather than just two or three
> piles.  Again, a valid comment.
> 
> Note that I'm entering this discussion with a mechanical background, so I'm
> not really familiar with the actual construction, use, or loading of these
> sheet piles.  I'm fairly certain, though, that you can use beam theory to
> adequately evaluate these piles, as long as you correctly evaluate any
> "non-standard" effects (such as the topics discussed above).
> 
> Andrew Moskalik
I'd like to thank Mr. Moskalik for his detailed explanations. This is what
realy makes Newsgroups woth the while. 
I never got to read that post by Ken Zagzebski, and I find it really
interesting since it would allow for a great simplification of the
problem. I really would appreciate it if it was posted again and
eventually a reference given to support this point. Intuitively, I do
agree completely with him, since the disruption of symmetry due to the
alternance of the sheet pile orientation is less and less important for a
growing number of piles.
My aim in this aalysis is to calculate the global deformation of a steel
pile wall taking into account the slippage encountered in the interlocks.
I think there is a minimum number of sheet piles from which the
deformations can be evaluated, and the result is then valid for any number
of them. 
But that is like saying that the deformations of a solid wall can be
calculated from the deformations of a certain number of beams stuck
together somehow. And that does not sound true to me...what do you think?
-- 
Enrique Juaristi, mechanical engineer

There is a new homepage on the Internet about Heat Flux Sensors, from 
TNO-TPD.
The Heat Flux Sensors are often used for rapid determination of thermal 
conductivity of insulating materials,
mass flow, endothermic processes, Earth, Soil/Agriculture, Labatory, 
Food & chemical processing etc
etc.....so I thought it might be interesting for you.
http://www.tno.nl/instit/tpd/product/heatflux/index.htm

Hi,
I'm working at an electronics manufacturing firm. Because we make almost
all our products on customer specifications, we have to built a lot of
prototypes.
For the prototypes we generally need to make some aluminum cooling
materials ourselves.
In the production versions of the products the aluminum parts are
anodized or passivated, but for the prototypes this is too expensive
(small quantities) or there's no time to have it done by an external
company.
Now I'm looking for a fast & easy way to give the aluminum parts a nice
finish.
It's just to get a nice look, there are e.g. no chemical resistive
requirements.
The only condition is that the thermal dissipation has to stay about the
same, so coating or painting cannot be used.
What I have tried in the past is to hang it in water with caustic soda.
The result is quite nice, but difficult to control. Sometimes black
appear spots appear. Also there's a health problem with the gases that
are developed.
Who knows a nice method?
Greetings,
Etienne van Ballegooijen

In Article ,
enrique.juaristi@crpht.lu (Enrique Juaristi) wrote:

>I never got to read that post by Ken Zagzebski, and I find it really
>interesting since it would allow for a great simplification of the
>problem. I really would appreciate it if it was posted again and
>eventually a reference given to support this point. Intuitively, I do
>agree completely with him, since the disruption of symmetry due to the
>alternance of the sheet pile orientation is less and less important for a
>growing number of piles.
I think you'll have to settle for the intuitively obvious rather than a
reference.  As the number of piles increases, the weak axis gets closer and
closer to horizontal.  You can fairly easily do a series of calculations to
find the relative twist for 2, 4, 6, etc. piles in a row to find at what
number the "simple" answer is "close enough."
>My aim in this aalysis is to calculate the global deformation of a steel
>pile wall taking into account the slippage encountered in the interlocks.
>I think there is a minimum number of sheet piles from which the
>deformations can be evaluated, and the result is then valid for any number
>of them. 
I think the slippage might be difficult to handle analytically.  You *can*
easily look at limiting cases for:
a) no slippage.  Here the pile wall is really one big beam and possible
twisting effects come into play as discussed before.
b) no friction.  Here the individual piles act seperately and you can
calculate the individual deflection of each pile, so long as the piles are
very long compared to the cross-section and the deflection itself.
These would give you maximum and minimum values.  However, I think you imply
that in a real situation, there is some slippage, and some friction between
the piles.  So:  how much friction?  If you knew that, you could determine
the shear transferred through the joint and make a pretty good stab at the
actual deflection.  Friction, though, is a pretty slippery topic (no pun
intended) in that the friction in the pile joint probably varies widely
depending on the tightness of the joint, the presence of oxides, water, or
dirt in the joint, the length of the pile, and other things I can't think
of.  So the actual frictional value, and thus the shear transfer, might be
hard to pin down.  If you do know the friction coefficient, you can:
1) For small loads, assume no slippage and calculate accordingly.
2) Calculate the maximum shear load capable of being transferred across the
beam boundary using the coefficient of friction.
3) Calculate the applied load corresponding to that shear.
4) Larger loads cause slippage, so individual piles act seperately. 
Calculate additional deflection accordingly.
[To be honest, the above analysis seems plausible to me, but I'm not sure
that I *haven't* overlooked something.  I'd hope someone else might comment
on the above...]
>But that is like saying that the deformations of a solid wall can be
>calculated from the deformations of a certain number of beams stuck
>together somehow. And that does not sound true to me...what do you think?
Well, you *can* assume a wall is a certain number of beams stuck together
somehow, as long as you correctly account for the forces between each beam. 
For example, you know there is a friction force between each pile that acts
as an applied shear force.  (In addition, there may be some normal force due
to a difference in the deflected shape of adjacent piles; I'm assuming this
is negligible)  Even for a solid wall, you can "cut" the wall into as many
little beams as you like and calculate a "correct" deflection, so long as
you account for all the internal forces acting on your cut surfaces.
Andrew Moskalik

I need help to find a free software in internet that let me study
the heat transfer in 3d solids of various matters.
thanks.....

On Thu, 24 Oct 1996 07:32:44 -0400, Yan Seiner, PE (cardinal@hargray.com) 
said...
>
>
>Software to my knowledge has never been the direct cause of a fatality. 
>If ever there was a fatality due to software failure, it ws because
>someone did not take the time to learn about the limitations of the
>software and maybe did not perform a sanity check on the results.
>
>In other words, the person who built the system should have insured that
>the software results are correct; or in the case of a control system,
>built the system so that mechanical limitations come into play before
>anyone is injured.
>
>Courts may have found liability in the software, but there is fault in
>the engineer who used the results without fully understanding them....
Huh?  How about the Airbus crash on takeoff in which the flight control 
system was convinced the plane was trying to land?  The aircraft was 
perfectly flyable, and would have taken off safely if the pilot's commands 
were not countermanded by the software ("What?  You can't have more power!  
You won't land gracefully!").  Now, please understand that the software was 
developed by flight controls engineers who should have known exactly what 
would happen in that flight scenario.
Software is now so integrated into many modern (particularly high 
performance) systems that it is not possible to view it as an add-on to the 
system (without the software, there is no workable system).
-Wayne
-- 
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 Dr. Wayne S. Hill                                    wshill@world.std.com
 Foster-Miller, Inc.           ***Disclaimed***           617-684-4228
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

Bill McBride wrote:
> 
> In article <54n0k7$890@alpha8.curtin.edu.au>, rklakakp@cc.curtin.edu.au wrote:
> 
> > Hello Engineering Bretheren,
> 
> Works on the Ammonia absorbtion cycle.  Look up some refrigeration books
> on this topic.  I always thought that this style of system would be great
> for car air cond. by using a bypass arrangement on the exhaust system to
> regulate the hot side.
> 
Could this be done without a compressor, and therefore without the
significant impact on fuel economy that present air conditioners have?
The problem, I think, is that the powers-that-be probably wouldn't allow
an ammonia based system to be placed in the front of a car.
-Paul

In article <326D1C2E.6FFF@ornl.gov>, c4p@ornl.gov says...
>I appreciate Peter's comments, however allowing free and frequent use of 
the tit
>le 
>"Engineer" before the public will make the term meaningless.  It's like 
marking 
>all 
>paperwork "Urgent":  pretty soon, nothing is urgent and all is routine.  I 
know 
>you're 
>not suggesting that everyone be called some type of engineer, but it should 
mean
>something when it is used.
You missed my point.  I was stating a fact, not an opinion.  This is the way 
it is.  Remember, I said that you are fighting history.  You want to make 
the change, rmember?
>> rightly so.  From my point of view, a PE simply serves the function of
>> licensing and standarization.  If your design is faulty, we can find you.
>> What is the problem?  The problem is ego.  A PE doesn't make you a 
"better"
>> engineer.
>
>"Simply serves the function of licensing and standardization"?  Ouch!  
Don't for
>get 
>about proof of some acceptable level of qualifications (beyond squeeking 
through
>engineering school) and legal acceptance of responsibility.  I doubt few 
non-P.E
>.s, if 
>any, have taken out liability insurance.  People who have adopted the title 
"Eng
>ineer" 
>for themselves, with some preceeding descriptor, have probably done so 
because i
Yes, a licenced PE should be insured.  That we agree on!
>them and their job seem more important.  Who's ego is really at work here? 
 Kind
>a makes 
>you wonder doesn't it?  You're right:  a P.E. doesn't (in itself) make you 
a bet
>ter 
>engineer; what it does do is legally make you an Engineer.
Again, you miss the point.  I was stating a fact about the way the term 
engineer is used.  You want to change that.  I don't see the need.  And 
perhaps you are right about ego.  I like being called an engineer.  I don't 
want the rules changed in the middle of the game by those with bigger egos!
>> I'm in the HVAC field, working as a sales rep.  I have an ME degree from 
an
>> accredited university, 13 years of experience, and am a full member of
>> ASHRAE.  I work with engineers all the time, in their offices, and on the
>> phone.  They call me because they know I have detailed knowledge of what 
I
>> sell, and that I can often prevent costly mistakes.  My job title is 
"sales
>> engineer", and I will defend that title, even though some others who do
>> similar things (without the degree/experince) also call themselves that. 
 Yes, there IS confusion! 
> Just 
>how does the public know "who" they are talking to when they call or meet 
with y
>ou or 
>others???  Do we have to ask each person we meet or call what their 
qualificatio
>ns are? 
> Non-graduate?  Graduate of non-accredited college?  Graduate of accredited 
coll
>ege?  
>EIT?  or P.E.?...A person's qualifications, background, and experience make 
a 
>difference.  As a P.E., I can't just take anyone's word over the phone, or 
even 
>in 
>person, as absolute truth; I am legally responsible for what I do - not my 
compa
>ny, me. 
> When people tell the public they are an Engineer, they ought to be one, 
legally
>.  JMHO.
Get real!  Again you are missing the point.  There is tons of confusion in 
the world.  Anyone who needs the services of any professional should be 
checking for relevant credentials.  Doctors come in all different flavors, 
for instance.
Peter Carmel
Sales Engineer

george wrote:
> 
> :Jim wrote:
> :Mark's Standard Handbook for ME's, 8th ed., states that the coefficient
> :of friction will get larger as the temperature falls and cites data from
> :Bowden for brass on ice which shows that as temperature falls from 0 deg
> :C to -60 deg C, friction coeff. goes from 0.025 to 0.14.  This would
> :explain the reason why it is easier to drive on ice when it's really
> :cold.
> 
> I have to cringe at the use of "coefficient of friction" applied
> to ice..  You'd get very different numbers if you
> looked at an ice skate, vs looking at a plate with a large
> area.  Actually, I expect the numbers should be vastly different
> near 0C and converge as you lower the temp..
> 
> --
> george
> george@mech.seas.upenn.edu
The referenced data was in a section for sleds and the data cited was
for sleds with metal runners on snow and ice.  
When comparing ice skates and plate, pressure and velocity differences
most likely invalidate much of the coefficient of friction data in
Mark's handbook.  The Mark's handbook section on friction, written by
Dudley D. Fuller, cites emperical data for coeffiction of friction where
the materials are under "moderate pressure".  When this is the case, the
frictional force is proportional to the normal load on the rubbing
surfaces, it is independent of the pressure per unit area of the
surfaces and of the rubbing speed (as long as speed is slow to not
affect surface temperatures).  
I agree, when skates and sled runners are being considered vs. plate,
velocity and pressure is probably high enough to make much of the linear
coefficient of friction empirical data less valid.
--
jim baker

In article <302322240058262homer@ccinet.ab.ca>, homer@ccinet.ab.ca says...
>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. 
That's why there is the title "Professional Engineer".  It is a legal
title meaning you have met the requirements of your state.  The title
"Engineer" carries no such implications and is simply either a degree
or job title, or a description of what one does.  (Those that graduate
with their doctorate can be called 'Doctor', but it doesn't have
the legal implications of 'Medical Doctor')
For the most part I've found that in my profession, EE, being a
Professional Engineer is usually not required unless you are working
for the government.  Also in firms where an PE is needed often several
non-PEs work under or with a PE who gives final approval and signs any
legal documents that require a PE's signature and seal.  That's not
to imply that non-PEs are any less engineers.
-Tim

On Thu, 24 Oct 1996 07:32:44 -0400, Yan Seiner, PE
(cardinal@hargray.com)
 said...
 >
 >
 >In other words, the person who built the system should have insured 
>that the software results are correct; or in the case of a control  >system,
 >built the system so that mechanical limitations come into play before
 >anyone is injured.
 >
If the necessity for the 'system' to prevent all sources of injury, it
would be impossible for an 'engineer' to design an automobile.  It is
certainly not the engineers responsibility to eliminate the possibility
of injury, just to ensure that the design solution employed is
reasonable in consideration of the intended purpose and end user.
In cases where the end use has an inherent potential for injury, the
government will generally regulate the use of the product as in the case
of driver/pilot licenses or industrial health and safety standards.
IMHO....
Dave Lawson

Looking for any information regarding FEA package selection based on 3D
modal analysis.  Which package(s) can best model 3D structures for a
finite modal analysis?
Niki Singlaub
js350159@lance.colostate.edu