\usemodule[units]

\usemodule[units]

[Willi Egger]

Hi,

I am not familiar with the ISO-norm concerning the use of upper and lower
case for units. - My question is, if there is a definition for the 'liter'.
Is the abbreviation 'l' of 'L'. Further how to write Milliliter: 'ml' or
'mL'?

Regards Willi

Re: \usemodule[units]

[Eckhart Guthöhrlein]

Willi Egger wrote:

> I am not familiar with the ISO-norm concerning the use of upper and lower
> case for units. - My question is, if there is a definition for the 'liter'.
> Is the abbreviation 'l' of 'L'. Further how to write Milliliter: 'ml' or
> 'mL'?

Both are officially correct at the moment. After an evaluation period, 
one of them will be dropped (perhaps, this evaluation period has already 
been extended...). I have the ISO standard at home, I will look up and 
mail the exact wording tomorrow.
In Europe, 'l' is common, whereas 'L' is preferred in the USA (and 
therefore in scientific literature). Pick your choice.
Apropos ISO: just think of the decimal sign. ISO says: "The decimal sign 
is a comma on the line." Now, look at numbers in English texts...

Eckhart

Re: \usemodule[units]

[Hartmut Henkel]

>From http://physics.nist.gov/cuu/Units/outside.html:

``The liter in Table 6 deserves comment. This unit and its symbol l were
adopted by the CIPM in 1879. The alternative symbol for the liter, L,
was adopted by the CGPM in 1979 in order to avoid the risk of confusion
between the letter l and the number 1. Thus, although both l and L are
internationally accepted symbols for the liter, to avoid this risk the
preferred symbol for use in the United States is L. Neither a lowercase
script letter l nor an uppercase script letter L are approved symbols
for the liter.''

Didn't know this. Sitting in Germany I thought it would be definitely
the `l'.

Greetings Hartmut

On Wed, 6 Feb 2002, Eckhart Guthöhrlein wrote:

> Willi Egger wrote:
> 
> > I am not familiar with the ISO-norm concerning the use of upper and lower
> > case for units. - My question is, if there is a definition for the 'liter'.
> > Is the abbreviation 'l' of 'L'. Further how to write Milliliter: 'ml' or
> > 'mL'?
> 
> Both are officially correct at the moment. After an evaluation period, 
> one of them will be dropped (perhaps, this evaluation period has already 
> been extended...). I have the ISO standard at home, I will look up and 
> mail the exact wording tomorrow.
> In Europe, 'l' is common, whereas 'L' is preferred in the USA (and 
> therefore in scientific literature). Pick your choice.
> Apropos ISO: just think of the decimal sign. ISO says: "The decimal sign 
> is a comma on the line." Now, look at numbers in English texts...
> 
> Eckhart

Re[2]: \usemodule[units]

[Giuseppe Bilotta]

Thursday, February 07, 2002 Hartmut Henkel wrote:

HH> Didn't know this. Sitting in Germany I thought it would be definitely
HH> the `l'.

Lowercase roman `l' is the one used in Italy as well.

--
Giuseppe "Oblomov" Bilotta

Symbol for the unit litre (was: \usemodule[units])

[Eckhart Guthöhrlein]

I think we can agree that 'l' is the common symbol in Europe, whereas 
'L' is used in the USA.
Here are some sources of further information for those interested.

ISO 31-0:1992(E)
"The two symbols for litre are on an equal footing. The CIPM will, 
however, make a survey on the development of the use of the two symbols 
in order to see if one of the two may be suppressed."

Selected parts from: Bureau Internationaldes Poids et Mesures, The 
International System of Units (SI), 7th edition, 1998 (available online 
at http://www.bipm.fr/enus/6_Publications/si/si-brochure.html)

"(c) This unit and the symbol l were adopted by CIPM in 1879 (PV, 1879,
41). The alternative symbol , L , was adopted by the 16th CGPM (1979, 
Resolution 6; CR, 101 and Metrologia, 1980, 16, 56-57) in order to avoid 
the risk of confusion between the letter l and the number 1. The present 
definition of the litre is given in Resolution 6 of the 12th CGPM (1964; 
CR, 93)." (p. 105)

"The 16th Conférence Générale des Poids et Mesures (CGPM), recognizing 
the general principles adopted for writing the unit symbols in 
Resolution 7 of the 9th CGPM (1948), considering that the symbol l for 
the unit litre was adopted by the Comité International des Poids et 
Mesures (CIPM) in 1879 and confirmed in the same Resolution of 1948,
considering also that, in order to avoid the risk of confusion between 
the letter l and the number 1, several countries have adopted the symbol 
L instead of l for the unit litre, considering that the name litre, 
although not included in the Système International d'Unités, must be 
admitted for general use with the System, decides, as an exception, to 
adopt the two symbols l and L as symbols to be used for the unit litre,
considering further that in the future only one of these two symbols 
should be retained, invites the CIPM to follow the development of the 
use of these two symbols and to give the 18th CGPM its opinion as to the 
possibility of suppressing one of them." (p. 131f)

"The CIPM, in 1990, considered that it was still too early to choose a 
single symbol for the litre." (p. 132)

So, the unit litre is in fact the only one with two officialy accepted 
symbols. So, besides any local practice, one has to consider which 
symbol - if any - is preferrable and should be supported.

Eckhart

Re: Symbol for the unit litre (was: \usemodule[units])

[Hans Hagen]

So, given the replies, i think that we should change the "L" into "l"; user 
can remap this to $el$ if needed; an alternative is to use a symbol liter, 
that then can be redefined.

ok?

Hans
-------------------------------------------------------------------------
                                   Hans Hagen | PRAGMA ADE | pragma@wxs.nl
                       Ridderstraat 27 | 8061 GH Hasselt | The Netherlands
  tel: +31 (0)38 477 53 69 | fax: +31 (0)38 477 53 74 | www.pragma-ade.com
-------------------------------------------------------------------------
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Re: Symbol for the unit litre (was: \usemodule[units])

[Eckhart Guthöhrlein]

Hans Hagen wrote:
> So, given the replies, i think that we should change the "L" into "l"; 
> user can remap this to $el$ if needed; an alternative is to use a symbol 
> liter, that then can be redefined.
> 
> ok?
> 

I can agree with 'l' being the default and 'L' being an option, but I 
think we should forget about that $\el$ (see my reply to Willi this 
morning). Either 'L' or 'l', but no script letters for units.
International standards allow both 'L' and 'l', regional usage varies. 
Maybe an option for internationalization, e.g. german -> 'l' and US 
english -> 'L'.

Eckhart

Re: Symbol for the unit litre (was: \usemodule[units])

[Willi Egger]

Hans,

It sounds as it is a question of taste. - To my taste I would be happy with
a 'l' because when you write 'mL' it is pritty strange to read. - I do hope,
that readers who encounter 'ml' are aware of the text they read. - Finally
we should not concentrate on the DAU (Der Dümmste Anzunehmende User).

Willi

----- Original Message -----
From: Hans Hagen <pragma@wxs.nl>
To: Eckhart Guthöhrlein <eckhart.guthoehrlein@uni-bielefeld.de>
Cc: ntg-context <ntg-context@ntg.nl>
Sent: Friday, February 08, 2002 10:05 AM
Subject: Re: Symbol for the unit litre (was: \usemodule[units])

> So, given the replies, i think that we should change the "L" into "l";
user
> can remap this to $el$ if needed; an alternative is to use a symbol liter,
> that then can be redefined.
>
> ok?
>
> Hans
> -------------------------------------------------------------------------
>                                    Hans Hagen | PRAGMA ADE | pragma@wxs.nl
>                        Ridderstraat 27 | 8061 GH Hasselt | The Netherlands
>   tel: +31 (0)38 477 53 69 | fax: +31 (0)38 477 53 74 | www.pragma-ade.com
> -------------------------------------------------------------------------
>                                    fall-back web server:
> www.pragma-pod.nl
> -------------------------------------------------------------------------
>
>

Re: Symbol for the unit litre (was: \usemodule[units])

[Johannes Hüsing]

On Fri, Feb 08, 2002 at 10:52:57PM +0100, Willi Egger wrote:
[...]
> that readers who encounter 'ml' are aware of the text they read. - Finally
> we should not concentrate on the DAU (Der Dümmste Anzunehmende User).
> 

you mean, citizens of the US of A? <dodge/>

-- 
Johannes Hüsing   There is something fascinating about science. One gets
hannes@ruhrau.de  such wholesale returns of conjecture from such a 
                  trifling investment of fact.                Mark Twain

Re: Symbol for the unit litre (was: \usemodule[units])

[Hans Hagen]

At 10:52 PM 2/8/2002 +0100, Willi Egger wrote:
>Hans,
>
>It sounds as it is a question of taste. - To my taste I would be happy with
>a 'l' because when you write 'mL' it is pritty strange to read. - I do hope,
>that readers who encounter 'ml' are aware of the text they read. - Finally
>we should not concentrate on the DAU (Der Dümmste Anzunehmende User).

[ah, you still can write german (or is this swiss)]

So i patched m-units:

%D After some discussion on the \CONTEXT\ mailing list in
%D february 2002 it was decided to go from L to l for liters
%D (Karel Wesselings alternative: \mathematics{\el}).

\getvalue{\v!eenheid} [Liter]  {l}             {liter}

Hans
-------------------------------------------------------------------------
                                   Hans Hagen | PRAGMA ADE | pragma@wxs.nl
                       Ridderstraat 27 | 8061 GH Hasselt | The Netherlands
  tel: +31 (0)38 477 53 69 | fax: +31 (0)38 477 53 74 | www.pragma-ade.com
-------------------------------------------------------------------------
                                   fall-back web server: 
www.pragma-pod.nl
-------------------------------------------------------------------------

Re: Symbol for the unit litre (was: \usemodule[units])

[K.H. Wesseling]

A little late, but it took some searching in old Xerox's piles. Late, 
but as far as I'm concerned a last word:

In a NASA special report:
-------------------------

E A Mechtly: The International System of Units. Physical Constants 
and Conversion Factors. (1964) NASA SP-7012. 

Under Conversion factors --- Alphabetical listing: To convert from 
liter to meter^3 multiply by 1.000028e-3.

It is in the same list as are, for example, the acre foot, bushel, 
cup, gallon, gill, hogshead, quart and tablespoon. The liter is not 
an SI unit.

In an IEEE spectrum special report:
-----------------------------------

D T Goldman (National Bureau of Standards): The metric system: its 
status and future. IEEE spectrum APRIL 1981, pp 60-63

Table VI Units in use with the International System
----------------------------------------------------
Name            Symbol   Value in SI Unit
----------------------------------------------------
minute          min      1 min = 60 s
....
liter           L*       1 L = 1 dm^3 = 10^-3 m^3
....
hectare ...
----------------------------------------------------
* An alternative symbol for liter is "l". Since "l" can be easily 
confused with the numeral "1", the symbol "L" is recommended for 
United States use.
----------------------------------------------------

The liter is not SI. Its symbol is "l" everywhere except in the USA 
where it is "L". 

History:
--------
The 1875 Convention of the Meter in Paris, convened at the initiative 
of the French government called for dissemination of international 
prototype standards of the meter and the kilogram.
....
As early as 1881, the First International Electrical Congres in Paris 
aproved the ampere as the practical unit of electrical current. 
....
This received official endorsement in 1935 from the Electrotechnical 
Commission in Scheveningen,...
....
The formal name of this system of units, Le Systeme International 
d'Unites (SI), was adopted in 1960.
....
As of 1980, the United States was the sole remaining industrial 
country that did not have as a specific goal the eventual adoption of 
the modernized metric system. 

Karel.
-------------------------------------------------------------------

On 10 Feb 2002, at 21:26, Hans Hagen wrote:

> At 10:52 PM 2/8/2002 +0100, Willi Egger wrote:
> >Hans,
> >
> >It sounds as it is a question of taste. - To my taste I would be
> >happy with a 'l' because when you write 'mL' it is pritty strange to
> >read. - I do hope, that readers who encounter 'ml' are aware of the
> >text they read. - Finally we should not concentrate on the DAU (Der
> >Dümmste Anzunehmende User).
> 
> [ah, you still can write german (or is this swiss)]
> 
> So i patched m-units:
> 
> %D After some discussion on the \CONTEXT\ mailing list in
> %D february 2002 it was decided to go from L to l for liters
> %D (Karel Wesselings alternative: \mathematics{\el}).
> 
> \getvalue{\v!eenheid} [Liter]  {l}             {liter}
> 
> Hans
> ----------------------------------------------------------------------
> ---
>                                    Hans Hagen | PRAGMA ADE |
>                                    pragma@wxs.nl
>                        Ridderstraat 27 | 8061 GH Hasselt | The
>                        Netherlands
>   tel: +31 (0)38 477 53 69 | fax: +31 (0)38 477 53 74 |
>   www.pragma-ade.com
> ----------------------------------------------------------------------
> ---
>                                    fall-back web server: 
> www.pragma-pod.nl
> ----------------------------------------------------------------------
> ---
> 
>