LETTERS

Aesop would have been proud to claim credit for Ellen Fussell's April [Careers department] article entitled "Offshoring-New hope for U.S. or inevitable as death?" After reading the article I wondered if the author's research itself hadn't been offshored. Her two main contributors, Dennis Brandi and Bill Radine, casually characterize the exporting of good U.S. technical jobs as a "natural process." They suggest that technical workers are nothing more than blind sheep being herded to the labor market slaughterhouse with their comments of ". . . we're just going to have to get used to it" or ". . . we need to live with it." I also take personal offense at their advising technical workers to accept their dismal fate in order to "innovate and recreate our economy."

Wake up my fellow tech workers! Like the turtle that found itself stranded atop a fence post, we technical workers should realize that we didn't get to our current location without someone's help.

That someone is your elected government and organizational officials. Lately, neither has been looking out for your interest.

Take some action to get off the fence post. Write, call, and e-mail all of your congress members and organizational representatives. Action will change our stranded position. Your failure to act will prove Fussell's article to be prophetic,

Joe C. Crawford, P.E., Toccoa, Ga.

Valve character

The Tutorial/Control Fundamentals column in the February 2004 issue, titled "Final control is the valve," is likely to be misleading to anyone new to this subject, especially the discussion subtitled "Body styles the valve."

The most popular types of valves-sliding stem globe valves and rotary valves-can be purchased with different inherent flow characteristics, which are primarily determined by the design of the plug or ball. In other words, valve type or body style does not necessarily determine flow characteristic. Body styles tend to be chosen more for the type of service (nature of the fluid, flow range, temperatures and pressures, shutoff requirement, etc.) and economic reasons than for the flow characteristic.

And, any discussion of flow characteristics, especially for those learning the subject, should delineate between "inherent" and "installed" flow characteristics. The "inherent" characteristic is the valve's flow versus position response for a constant pressure drop over the entire range.

The "installed" characteristic is how it will respond when installed in the real process (usually not constant pressure drop), alluded to by the author of the column with the statement "perform a complete dynamic analysis on the piping system to obtain a definite characteristic." The experienced process control engineer will usually be able to determine from the general design of the process that is to be controlled what inherent characteristic to specify. Usually, for good closed loop control, the goal is to approximate a linear installed characteristic (unless the installed characteristic itself is being used to offset some other nonlinearity in the control loop).

Finally, the statement "Quick opening valves . . . may also be appropriate for applications requiring near linear flow" does not seem to make sense at all. The flow characteristic of quick opening valves is highly nonlinear.

The ISA Handbook of Control Valves and the ISA standard on which it is based are very good authoritative sources on this subject, to which the columnist and those learning the subject may wish to refer.

Rick Meeker, Process Control Solutions, Inc., Tallahassee, Fla.

Where's the wealth?

The ["Overseas jobs 'just the way it is'," Careers department, March 2004] article misses a crucial point. For six thousand years nations have protected their internal economy because that is what citizens exist on. Globalization is sequestering wealth into the hands of the few, and the many are left without or on a dole system, not very satisfying. Tyrants thrive on dissatisfied people. The U.S. was on the brink of civil war in 1933 when there were far fewer people than now. America is now a three-way powder keg with the fuses lit. I saw with my own eyes the dissatisfaction with the Vietnam War, and people had war in their eyes. We only had to quit that war to end the violence, but what do we do when 290 million people face an empty larder, and there is no promise for tomorrow?

I wish Americans would take a critical look at the plutocrats and the oligarchs who are running this country into bankruptcy and do the obvious!

Robert Gibson, Aurora III.

Digital Babel

The refinery explosion in Algeria can be a sign that our industries are becoming unsafe because of the chaotic state of digital-based automation. In the past, a standard signal was used worldwide to convey measurement information. Today, because of the lack of international standardization, our digital data highways "speak" eight different languages. This is because supplier groups want to create captive markets. Therefore, if a refinery installs control systems from different suppliers, the networks will not easily communicate. Well, would you want to fly with a pilot who did not understand the messages of the control tower?