7, 1998 Design News
Letters to the Editor
Readers state their views
The measure of metric
With regard to J.C.R. Forehand's letter about the metric
system (Letters, 6/8/98), I think that the writer
is making much ado about nothing. While the complaint
that the nomenclature involved in this system is full
of "tongue twisters" is rather lame, what
amuses me is the complaint that there is a "lack
of flexibility" in the metric system!
What other system of units allows you to so easily
interchange sets of units with others, without any complicated
conversion factors (e.g. 1 Pascal = 1 Newton per meter
squared, 1 Joule = 1 Newton meter and so forth)? And
who really needs "fractional arithmetic practice"?
Perhaps the writer subscribes to the Luddite school
of thought, but the metric system has been around for
a long, long time, and it is time that U.S. and, to
an extent, U.K. engineers accepted the fact that the
rest of the world uses metric very successfully. Of
perhaps more immediate concern is the fact that students
at high schools and colleges are taught in the metric
system, and then have to deal with the archaic imperial/English
unit system in the workplace. There are many important
things to battle in this ever-changing world, but this
issue surely isn't one of them.
G. P. Hatch
Elk Grove Village, IL
Comments on supplement
I'm a mechanical engineer working in an older semiconductor
fabrication facility (of fab). I found your special
supplement on semiconductor manufacturing (Design
News, 6/8/98) very interesting.
I would like to make the following comments:
The next wafer size for the industry will be 300 mm,
with features of 0.18 microns, but not everyone is aggressively
moving in that direction. There are advantages to using
these new, and very expensive, technologies and for
some companies it makes senses to move in that direction.
But, many companies are profitable with older fabs running
5- or 6-inch wafers. These companies make products that
do not require the latest and greatest technology, and
they can't afford to build a $2 billion fab. By using
older, well-understood, and cheaper technology, these
companies can continue to grow and make a profit.
Your forecast for growth of the semiconductor and semiconductor
equipment industries is based on old data. These industries
will not grow by 20% this year. The Asian economic problem
has hit both industries very hard and they will shrink
this year. Lam Research, a semiconductor equipment company,
recently announced they were laying of 1,100 people,
or 25% of their work force. This is after laying off
700 people a few months ago. Several other semiconductor
and semiconductor equipment companies have announced
These industries will bounce back in a year or two
and be larger than ever. A few years ago they grew by
more than 30% for two years in a row. Semiconductors
are not going away anytime soon. If anything, they will
be added to more products as the cost per feature continues
Senior Equipment Engineer
Regarding the letter in your 6/22/98 issue on perpetual
motion, there are well-established criteria concerning
"perpetual motion" devices as viable technology.
Simply put, any such device must be proven not to violate
the first or second law of thermodynamics. That's it.
That's the whole list.
From what I've read, all devices purported to be "perpetual
motion" (that were not outright frauds) have been
found upon careful examination to violate one or both
of those principles. I think the U.S. Patent Office
has for quite some time refused to accept patent applications
for any such machines.
J. A. Oliver
Environmental Growth Chambers
Solar array help
Regarding Chris Hedberg's "Solar Array" question
(Letters, 5/18/98), another reader responds:
For the best information on product and component sources
and also on practical construction, try Home Power
magazine. This should be available to you at the more
complete magazine shops. It is bimonthly by subscription.
All sorts of solar and alternative energy products
are advertised, and articles give practical instruction
on installation etc. The publishers are basically old
hippies who "went techie."
The advertisers are for new equipment, but surplus
solar panels have been advertised as available recently,
as more and more government-funded solar power plants
shut down and are scrapped out. (I guess the energy
crisis is not important anymore.)
Give it a whirl.
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