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MalBru
Germany
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 Posted - 01/11/2010 : 02:55:19 AM
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Hi,
is there any way you guys could tell me the reference of one of your fitting functions? I'm looking for the origin of your LangmuirEXT1 Fitting function, I've never seen that type...
Regards,
Malte
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larry_lan
China
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Posted - 01/11/2010 : 9:09:10 PM
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Hi Malte:
We made this function from:
Equation 4.3.10
Handbook of Nonlinear Regression Models
David A. Ratkowsky
Marcel Dekker, Inc. New York and Basel
And this function is original comes from:
Sibbesen, E. (1981).
Some New Equation to Describe Phosphate Sorption by Soils,
J. Soil Sci. 32, 67-74.
Thanks
Larry
OriginLab Technical Services
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kmulroy
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Posted - 04/25/2010 : 4:44:05 PM
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I was unable to find the article referenced above. From what I know about Langmuirs equation, a is the sorption maxima. Is b the slope and c the y-intercept? What equation LangmuirEXT1 and LangmuirEXT2 is better to understand sorption on soils?
Thanks in advance. |
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larry_lan
China
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Posted - 04/25/2010 : 11:12:57 PM
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Hi:
You can find Ref 1 from Amazon, and maybe you need to pay for Ref 2. Or, you can ask some university library nearby to see if they have pay for the Wiley InterScience database.
I am not quite sure about the physical meanings of this function because I am not major in this area. However, you can see LangmuirEXT2 is just the reparametrized formula of LangmuirEXT1 by dividing numerator and denominator by abX^(1-r).
Hope this helps.
Thanks
Larry |
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Reference for fitting functions