[ RadSafe ] SI; Now or never?
Bernard Cohen
blc+ at pitt.edu
Mon Feb 20 09:28:05 CST 2006
It seems to me that the really big problem is with screw threads. If
we went completely metric, all screw threads in U.S. would be useless,
and that involves prectically every mechanical, electrical, electronic,
etc machine or gadget we use.
Neill Stanford wrote:
>But the size of the coke can isn't the issue in my mind. Non-SI gets
>problematic when you are scaling a quantity. Different units for different
>ranges of volume for example, with an often obscure conversion factor, makes
>scaling non-intuitive and problematic. If someone is buying Coca Cola in
>volume and wants to have enough to give 100 people the same amount as in a
>normal can, I can arrive at 35.5 liters a lot faster (and with greater
>accuracy and precision) than 9.38 US gallons, or 7.8 imperial gallons, or
>37.5 quarts, or 75 pints, or 150 cups, or 1200 oz, or 2400 tablespoons. And
>when I order it, of course I need to use the appropriate unit for that
>volume: gallons.
>As for the conversion factors, they may be simple and well defined, but it
>is this kind of arithmetic (rather than mathematics), with all of the
>opportunities for blunders, that gets us into problems.
>
>
>Neill Stanford, CHP
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>Stanford Dosimetry, LLC
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>-----Original Message-----
>From: radsafe-bounces at radlab.nl [mailto:radsafe-bounces at radlab.nl] On Behalf
>Of Jean-Francois, Stephane
>Sent: Friday, February 17, 2006 8:06 AM
>To: radsafe at radlab.nl
>Subject: RE : [ RadSafe ] SI; Now or never?
>
>This discussion comes on a yearly basis on RADSAFE. Just for your info, even
>in Canada where we are "SI", we do have "odd" sizes like my V-8 tomato juice
>of 354 ml or Coca Cola of 355 ml....So what do you think is a 355 ml can of
>Coke ??? Do you think this is real SI ? The only real conversion I see is
>for milk where we have REAL 500 ml or liters etc. and of course for
>regulatory issues like speed , radioactivity, dose rate etc.
>
>But really I don't care about SI or non-SI, for Health Physics purposes.
>Either way, there is always a factor you can use....only maths.
>
>Stéphane Jean-François, Eng., CHP
>Manager, Environmental and Health Physics services Merck Frosst Canada
>514-428-8695
>514-428-8670
>stephane_jeanfrancois at merck.com
>www.merckfrosst.com
>
>
>
>
>-----Message d'origine-----
>De : radsafe-bounces at radlab.nl [mailto:radsafe-bounces at radlab.nl] De la part
>de Dimiter Popoff Envoyé : Friday, February 17, 2006 8:46 AM À :
>radsafe at radlab.nl Objet : RE: [ RadSafe ] SI; Now or never?
>
>
>John,
>your two sets of wrenches example demonstrates that there are serious issues
>associated with the units in use. BTW, I had not thought of this problem;
>you can encounter English sized bolt heads here, but seldom enough to write
>the issue off.
> In spectrometry, not that I would be unhappy to sell two instruments
>instead of one - each per metric system - if I could, but I cannot. :-) Just
>the slightest hint of any conversion problem or whatever unit issue would
>mean a lost customer... (good we all count the time in seconds, energy in eV
>etc.... and activity, well, I keep this "user defined", no big issue inside
>a big software).
>
>Dimiter
>
>------------------------------------------------------
>Dimiter Popoff Transgalactic Instruments
>
>http://www.tgi-sci.com
>------------------------------------------------------
>
>
>
>
>> -------Original Message-------
>> From: John Jacobus <crispy_bird at yahoo.com>
>> Subject: RE: [ RadSafe ] SI; Now or never?
>> Sent: Feb 17 '06 15:08
>>
>> Consider the problem if you have two sets of wrenches for working on
>>your car, metric and English. I do.
>> How many people in European and Asian countries do?
>>
>> I am still unit (and tool) "challenged."
>>
>> --- Dimiter Popoff <didi at tgi-sci.com> wrote:
>>
>> > I suspected something like that :-).
>> > My guess is that the radiation units are those > taking about the
>>
>>
>>>least effort to switch. I doubt there are many > people who > grew
>>>
>>>
>>up in the US and think millimeters rather than > fractions > of an
>>inch, litres rather than gallons/pints > (whatever....:-), > kmph
>>rather than mph etc...
>> > The chip industry has made the move - they just > specify >
>>dimensions both in millimters and inches, and, well, > we all > use
>>Volts, Amps, Watts etc.
>> > I do wonder how it is with temperatures. Those of > the >
>>listmembers doing lab work must be used to degree > Celsius (and/or
>>
>>
>>>Kelvin), however, when it comes to weather - do they > still think
>>>Fahrenheit? My guess is they have developed a > precise >
>>>
>>>
>>calculator to do the conversion a long time ago (I > have > to
>>struggle every time I am confronted with degree > F, > although
>>evenually I manage it... :-).
>> >
>> > Dimiter
>> >
>> >
>>
>> +++++++++++++++++++
>> "It is not the job of public-affairs officers to alter, filter or
>>adjust engineering or scientific material produced by NASA's technical
>>staff."
>> MICHAEL D. GRIFFIN, NASA administrator.
>>
>> -- John
>> John Jacobus, MS
>> Certified Health Physicist
>> e-mail: crispy_bird at yahoo.com
>>
>> __________________________________________________
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>>
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