I must admit that I have never heard of that measurement.
Between 1970 and 1972 I worked in the de Beers diamond synthesis laboratory in Johannesburg. The units used when estimating the pressure inside the synthesis cell was kilobars - diamonds were synthesized at 50 to 60 kbar. The pressure of the oil used to generate this pressure was measured in psi (typically 2000 - 3000 psi). Of course, now they should be talking about 5-6 GPa and oil pressures of 15 - 20 MPa. For the benefit of any techies, the high pressure was obtained by using a piston that had a diameter of between 500 mm and 1 m pushing against a cell that had a diameter of 25 to 35 mm (depending on the actual model). Using SI units, it is easy to calculate the efficiency of the system - using the mixture that I had in the early 1970's, it was not as easy. (South Africa adopted the metric system in the early 1970's). _____ From: [email protected] [mailto:[email protected]] On Behalf Of Bill Potts Sent: 15 July 2009 07:40 To: U.S. Metric Association Subject: [USMA:45369] Strange Unit I just came across a unit I've never seen before: ksi. It stands for kilopounds force per square inch and is used as a stress measurement (especially for metals). It turns out that 1 ksi equals about 6.9 MPa (or, more roughly, 7 MPa). Is anyone familiar with this, and in particular, how widespread its use might be? It's of interest to me, because I'm about to propose on a contract to create a Web site for a company that is very closely associated with another company that uses ksi (and only ksi) on its own site. Bill _____ Bill Potts W <http://wfpconsulting.com/> FP Consulting Roseville, CA http://metric1.org <http://metric1.org/> [SI Navigator]
