Posted by Rick Denney trying again on July 23, 2001 at 13:00:16:
In Reply to: Re: Re: Re: Re: Re: Damping posted by Joe S. on July 20, 2001 at 19:15:10:
Since my other post apparently got hosed, I'll try again.
The controls of a power plant are just as much in the domain of engineers as the structure. In fact, a mechanical engineer will design the controls and a civil engineer will design the structure. And making a mistake in the controls can have disastrous consequences. For example, Three Mile Island was caused because the operators had no means of measuring the level and temperature of the cooling water except through the control system which had failed. They could have averted the disaster had a $10 toilet-bowl float (to detect low cooling water levels) alerted them to measure temperature using a simple thermocouple with external connections available from the control room. The thermocouple was there, but inaccessible except to the control system.
Aphorism #1: Good judgement comes from experience, but experience comes from poor judgement.
And those old bridges are, by today's standards, extremely heavy, narrow, and short of span. You only see the ones that didn't fall down. Modern engineers are not allowed to learn by trial and error, even if it may still be the best way to arrive at the optimal tuba (there, error is allowed especially since one man's error is another man's artistic tool).
Aphorism #2 (with apologies--Ben Franklin didn't mince words): Experience keeps a dear school, but fools will learn in no other.--Poor Richard's Almanack
Rick "not Poor Richard" Denney