[USMA:24695] Re: suggestion and inquiry: SI and ICAS

[kilopascal]

Title: suggestion and inquiry: SI and ICAS

2003-01-30   I don't understand the need to create new time units to parallel the second, when we have the second, an SI unit.  The problem with all of these ticks and tocks is they are based on the variable earth day.   Yes, it is possible, as you have shown below to give the ticks and the tocks the same definition as the SI second.  One can even define the foot and inch by the same definition as the meter.    The second and the SI prefixes are perfectly suitable for all measurements of time.  We don't need more complicated time units to deal with.  Let's all agree to scrap the whole idea.   John           ----- Original Message ----- From: AAT at www.aatideas.org To: U.S. Metric Association Cc: [EMAIL PROTECTED] Sent: Wednesday, 2003-01-29 12:49 Subject: [USMA:24678] suggestion and inquiry: SI and ICAS Madan, Thank you for the suggestion about notation of years. The AAT is considering ICAS revisions in light of comments and suggestions, and hopes to be able to address these metrication concerns in future programming. At the same time, other areas of development are also on the board. One is to specify an IDC fixed unit that is fixed or derived from the SI second: A method for defining a fixed tik unit based on the SI second is under consideration. A tik may be designated as fixed from second (ffs) by the following formula: By custom there are 86,400 seconds in a day, and there are 100,000 tiks in a chron. A tik fixed from second (ffs) is thus 0.864 seconds, and may be expressed as tt010 ffs. A chron that is fixed from second may be likewise designated as t 1 ffs (equal to 86,400 seconds). "The second is the duration of 9 192 631 770 periods of the radiation corresponding to the transition between the two hyperfine levels of the ground state of the caesium 133 atom." (SI 2.1.1.3) From this a tik fixed from the second would is derived from [9,192,631,770 x 0.864 = 7,942,433,849.3] 7,942,433,849.3 periods of the radiation corresponding to the transition between the two hyperfine levels of the ground state of the caesium 133 atom per SI 2.1.1.3 (however calculation or application of measure is not validated). Alternately one tok (tt100) ffs (8.64 s) would be 79,424,338,493 periods per SI 2.1.1.3 (however calculation or application of measure is not validated).   However at this time the AAT ICAS department must inquire into the validity of these derivations. Sincerely, -- Ron Stone, programs manager Alliance for the Advancement of Technology (AAT) [EMAIL PROTECTED] http://www.aatideas.org AAT at www.aatideas.org PO Box 141155 Mpls., MN 55414-1155 USA