04/03/2000 Design News
Letters to the Editor
Readers state their views
No more call waiting
If the device you described in Breaktime (2/20/00), which disconnects any phone call on demand, were real, I would purchase 500 of them in an instant. I would hand them out to everyone who has those bumper stickers that say "Hang Up And Drive." It would be the best invention in the world next to the automobile.
-Randy Prier
Controls Engineer
The significance of metric
Although I largely agree on the point made by Kevin Acheson (DN Letters 12/20/99) about numbers being meaningless without units, I disagree on his last remark that switching to metric will not solve stupid errors. Universally switching to SI (metric) units will eliminate the errors stated, as there is only one valid unit for a dimension. In length it is the meter. So when it is clear the dimension is length, the unit is meter. When the situation described makes a short notation possible, the user is free to use 5 km for 5000 m or 5,000,000 mm. The difference is in measurement. Whereas 5.000 km IS the same as 5000 m, 5 km can mean 4.5 & x & 5.5 km. Significant numbers are of the issue here, not the units.
-Jaap van der Heide
Design Engineer
TNO Automotive-Delft-The Netherlands
Software no substitute
In the 2/21/00 issue of Design News, the article titled, "5 FEA Packages for Less than $6,000" inadvertently illustrates an important topic. It is true that CAE software is quickly becoming both more powerful and easier to use. FEA software vendors are succeeding in expanding their market by targeting what the author calls "everyday design engineers" as new customers. This is both good and bad. The article describes the many benefits of simulating product performance early in the design process. Unfortunately, the article fails to discuss the serious hazards of engineering analysis in the hands of untrained and inexperienced FEA users. Even the simplest analysis requires the user to make numerous assumptions and approximations based on engineering judgment. A flawed analysis leads to either unnecessary design changes or a false sense of confidence, sometimes with catastrophic consequences. Just as owning a word-processor does not make one a writer, owning FEA software does not make one an engineering analyst. Software is still not smart enough to replace good old-fashioned engineering.
-Wayne P. Rogers, Ph.D., P.E.
Mechanical Process Development and Training Department
StorageTek
The WWF and violence
I read Paul Teague's "Resolutions" editorial (DN 2/21/00) today...one day after the most recent school shooting near Flint, MI, and couldn't agree more with his comments. I was somewhat curious about the pro wrestling item, though. Is Paul referring to the WWF or rather to the real kind of wrestling that takes place at high schools and college campuses? If it's the WWF variety, then I feel he has some kind of blinders on. The WWF also feeds the "culture of violence" in a big way...in my opinion. Thanks for an informative publication.
-Daniel C. Morris
Caterpillar Inc. Control System Products Division
Taking a stand
I applaud Mr. Teague for taking a stand against media violence. As Paul pointed out, common sense-a trait rarely used by our government officials-tells us that the continuous exposure to violence in the media can't help but adversely influence our impressionable children. This concept was amplified for me when I was listening to an interview with a retired army general on public radio. He outlined how our society trains our children, through violence in the media, to associate violence with pleasure. Thank you for your candor and courage in speaking out in support of the health and welfare of the future generation.
-Chris Wells
Guidant Corp.
St. Paul, MN