"Lpa","Lwa"- What is it?
ISTEP
Technical Specifications
Sound pressure level Lpa
---
(at the operator's place, according
to ISO 6081, in dBa(A)).........................97
What is this -"Lpa"?
Our dictionaries do not give answer this question (www.acronyfinder,com too).
Thanks in advance.
Igor
Fabian
"ISTEP" hu kiteb fil-aue
> In the text in English, which was writed by German firm I found out
next:
>
> Technical Specifications
>
> Sound pressure level Lpa
> ---
> (at the operator's place, according
> to ISO 6081, in dBa(A)).........................97
>
> What is this -"Lpa"?
> Our dictionaries do not give answer this question
It is obviously an abbreviation. It looks like it is a measure of sound
pressure. I have no idea what units are usually used to measure sound
pressure, but I strongly suspect that middle letter "p" stands for
"per".
--
--
Fabian
Once you get over the initial panic stage, oxygen starvation is actually
a rather pleasant sensation, almost like falling asleep.
Evan Kirshenbaum
> "ISTEP" hu kiteb fil-aue
>
> > In the text in English, which was writed by German firm I found out
> next:
> >
> > Technical Specifications
> >
> > Sound pressure level Lpa
> > ---
> > (at the operator's place, according
> > to ISO 6081, in dBa(A)).........................97
> >
> > What is this -"Lpa"?
> > Our dictionaries do not give answer this question
>
> It is obviously an abbreviation. It looks like it is a measure of sound
> pressure. I have no idea what units are usually used to measure sound
> pressure, but I strongly suspect that middle letter "p" stands for
> "per".
It appears to be "A-weighted sound pressure", whatever that means. I
presume that "L" is "loudness" and "p" is "pressure".
--
Evan Kirshenbaum +------------------------------------
HP Laboratories |If all else fails, embarrass the
1501 Page Mill Road, 1U, MS 1141 |industry into doing the right
Palo Alto, CA 94304 |thing.
| Dean Thompson
kirsh...@hpl.hp.com
(650)857-7572
Lars Eighner
<AD2Oq...@velissa.kiev.ua>,
the lovely and talented ISTEP
broadcast on alt.usage.english:
> In the text in English, which was writed by German firm I found out next:
> Technical Specifications
> Sound pressure level Lpa
> ---
> (at the operator's place, according
> to ISO 6081, in dBa(A)).........................97
> What is this -"Lpa"?
LpA is the A-weighted sound pressure level and LwA is the
A-weighted sound power level.
Lp is the sound pressure level.
Like pH, these symbols are virtually irreducible.
You should consider them as a single symbol. LpA is usually
expressed in decibels and LwA is usually expressed in watts.
However they are used to measure sound levels near jet
engines and within sealed hard disc drives and many sound
levels in between so you may find them expressed in more
convenient units.
They certainly do not stand for L x p x A or L/A or anything
like that.
As for how they are measured and calculated, I'm afraid you
will have to find an acoustical engineer to tell you.
Essentially A-weighting is a mathematical method of equating
a varying sound level with a steady sound level. I gather
this is a bit more complicated than the root-mean-square
method.
> Our dictionaries do not give answer this question
> (www.acronyfinder,com too). Thanks in advance. Igor
--
Lars Eighner -finger for geek code- eig...@io.com http://www.io.com/~eighner/
We all agree on the necessity of compromise. We just can't agree on
when it's necessary to compromise. --Larry Wall
KT
negative logarithm to base 10 of the concentration of hydrogen ions
(protons) in a solution.
--
KT
"Lars Eighner" <eig...@io.com> wrote in message
news:slrnb37a50....@dumpster.io.com...
Lars Eighner
<3e33eb2e$1...@news.starhub.net.sg>,
the lovely and talented KT
broadcast on alt.usage.english:
> I always thought that pH stands for potential hydrogen, which is the
> negative logarithm to base 10 of the concentration of hydrogen ions
> (protons) in a solution.
The point being, it is not p x H or something *per* H nor
anything even remotely intuitive.
--
Lars Eighner -finger for geek code- eig...@io.com http://www.io.com/~eighner/
All lies and jest; still, a man hears what he wants to hear and
disregards the rest. --Paul Simon
Martin Ambuhl
> In the text in English, which was writed by German firm I found out next:
>
> Technical Specifications
>
> Sound pressure level Lpa
> ---
> What is this -"Lpa"?
I would expect that DIN or VDI could answer your question. I would guess
that it is based on "Laut" (sound), "Prüfverfahren" (testing method), and
"a-weighted." But that's just a guess.
Evan Kirshenbaum
> I always thought that pH stands for potential hydrogen, which is the
> negative logarithm to base 10 of the concentration of hydrogen ions
> (protons) in a solution.
Both MW and the OED derive the "p" from German "Potenz" (power). The
OED notes that it was first used by Sörensen in 1909 in
_Biochem. Zeitschr._, and the "H" was a subscript.
I tend to mentally expand it as "proportion" or, more often "percent",
even though I know the latter to be incorrect.
--
Evan Kirshenbaum +------------------------------------
HP Laboratories |Oh, forget it: I can't write about
1501 Page Mill Road, 1U, MS 1141 |this anymore until I find a much
Palo Alto, CA 94304 |more sarcastic typeface.
| Bill Bickel
kirsh...@hpl.hp.com
(650)857-7572
Earle Jones
Evan Kirshenbaum <kirsh...@hpl.hp.com> wrote:
> "KT" <kwun...@msn.com> writes:
>
> > I always thought that pH stands for potential hydrogen, which is the
> > negative logarithm to base 10 of the concentration of hydrogen ions
> > (protons) in a solution.
>
> Both MW and the OED derive the "p" from German "Potenz" (power). The
> OED notes that it was first used by Sörensen in 1909 in
> _Biochem. Zeitschr._, and the "H" was a subscript.
>
> I tend to mentally expand it as "proportion" or, more often "percent",
> even though I know the latter to be incorrect.
*
See:
http://mathforum.org/library/drmath/view/56363.html
"Jens Norby (2000) has recently clarified the origin and meaning
of the little 'p' in pH. The H, of course, refers to H+, the
hydrogen ion, whose concentration contributes to acid strength.
Hence, many have supposed that the 'p' refers to power (or the
French puissance or German Potenz). Some have taken this to mean
the power of 10, referring to the logarithmic calculation of pH.
Similarly, others construe the 'p' as denoting the potential, or
intensity, of hydrogen (or in Latin, potentia).
But Norby traces the 'p' to a simple mathematical convention of
naming variables. Danish chemist Soren Peter Lauritz Sorensen
proposed the pH scale in 1909. But he did not give an explicit
reason for choosing 'p' in his original two papers. Sorensen was
primarily concerned with determining the H+ concentration
electrometrically. His central equation involved values for
measurements at two electrodes, which he arbitrarily designated
p and q. To develop a standard, he set the non-hydrogen
component, Cq, at 1.0 and solved for the hydrogen ion
concentration, Cp, or 10-p. The number p he suggested calling p+H.
Sorensen ultimately defined pH as the negative logarithm of a
factor for hydrogen concentration relative to a normality of 1.0,
not (as many texts today do) as the negative logarithm of the
hydrogen ion concentration. (As Norby notes, one cannot take a
logarithm of a measurement with units.) "
earle
*