A remaining objection is the "double operator" (/ then .) with ambiguous grouping:
Is it "(30$/kA). m" or "30$/(kA . m)"? Conventional algebra is not strictly sequential as are many computer algorithms. Gene. ---- Original message ---- >Date: Wed, 8 Apr 2009 09:40:22 +1000 >From: Pat Naughtin <[email protected]> >Subject: [USMA:44467] Re: Strange SI units >To: "U.S. Metric Association" <[email protected]> > > Dear John and Ezra, > Two thoughts occur to me. > 1 How wonderful is the metric system? Here is an > obscure application — getting the electrical > energy form an off-shore wind energy source, and in > a matter of moments the engineers can derive an > appropriate unit, directly from the SI base units, > that is coherent and the best fit for this > application. > 2 Isn't it odd that the 'unit' for currency, dollar > (symbol $), was fitted to numbers at the front > rather than at the back; we write two dollars as $2 > rather than as 2 $. In the application that Ezra > found, it would make more sense, to me at least, if > it was written as 30 $/kA·m with all symbols after > the number. > Cheers, > Pat Naughtin > Geelong, Australia > On 2009/04/08, at 6:29 AM, John M. Steele wrote: > >It is a kiloampere-meter. > >It is an alternate way to express an amount of wire. To carry a given >current, a wire needs a certain cross-sectional area, but the area >depends on what the wire is made of. > >A way to equalize and express costs across wire types is to rate by >current carried, for each wire type that will require a certain area. >Multiplied by the length of the wire, that gives volume and should be >proportional to cost (at least fairly proportional). > >However, I don't think I've ever seen it before. I had to read the >conext in the article to see what it is about. It is a clever way to >relate the cost of the wire to its mission (carrying current for a >distance) rather than purely by dimensions. > >It is analogous to looking at cost of fuels per unit of heat energy >rather than by volume or weight. >--- On Tue, >4/7/09, [email protected] <[email protected]> wrote: > > From: [email protected] <[email protected]> > Subject: [USMA:44462] Strange SI units > To: "U.S. Metric Association" <[email protected]> > Date: Tuesday, April 7, 2009, 3:46 PM > > Just came across this article: > > http://ptonline.aip.org/journals/doc/PHTOAD-ft/vol_62/iss_4/25_1.shtml > > but was flummoxed by this part: > > $30/kA·m > > What the heck is kA·m and why do they use it? > > Ezra > > Pat Naughtin > PO Box 305 Belmont 3216, > Geelong, Australia > Phone: 61 3 5241 2008 > Metric system consultant, writer, and speaker, Pat > Naughtin, has helped thousands of people and > hundreds of companies upgrade to the modern metric > system smoothly, quickly, and so economically that > they now save thousands each year when buying, > processing, or selling for their businesses. Pat > provides services and resources for many different > trades, crafts, and professions for commercial, > industrial and government metrication leaders in > Asia, Europe, and in the USA. Pat's clients include > the Australian Government, Google, NASA, NIST, and > the metric associations of Canada, the UK, and the > USA. See http://www.metricationmatters.com for more > metrication information, contact Pat > at [email protected] or to get the > free 'Metrication matters' newsletter go > to: http://www.metricationmatters.com/newsletter to > subscribe.
