Rejuvenation of the neck

Cook, William R.; Cook, Kim K.

doi:10.1201/b14324-26

Cited by 2 publications

(1 citation statement)

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“…For example, the production rate in the numerical model was constant with soil depth over a finite thickness layer, while the analytical model did not specify λ (z). The important consideration here was to satisfy the no‐flux boundary condition at the bottom of the soil layer in both models, and a depth‐independent λ fulfills this condition, while an exponentially decaying production function does not 16. Another difference between model designs was that a perfectly mixed chamber headspace CO 2 was obtained by assigning a large value to its diffusion coefficient in the numerical model, while in the analytical model the chamber was represented as a boundary condition.…”

Section: The 3d Numerical Modelmentioning

confidence: 99%

Reduction of bias in static closed chamber measurement of δ¹³C in soil CO₂ efflux

Ohlsson¹

2009

Rapid Comm Mass Spectrometry

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The (13)C/(12)C ratio of soil CO(2) efflux (delta(e)) is an important parameter in studies of ecosystem C dynamics, where the accuracy of estimated C flux rates depends on the measurement uncertainty of delta(e). The static closed chamber method is frequently used in the determination of delta(e), where the soil CO(2) efflux is accumulated in the headspace of a chamber placed on top of the soil surface. However, it has recently been shown that the estimate of delta(e) obtained by using this method could be significantly biased, which potentially diminish the usefulness of delta(e) for field applications. Here, analytical and numerical models were used to express the bias in delta(e) as mathematical functions of three system parameters: chamber height (H), chamber radius (R(c)), and soil air-filled porosity (theta). These expressions allow optimization of chamber size to yield a bias, which is at a level suitable for each particular application of the method. The numerical model was further used to quantify the effects on the delta(e) bias from (i) various designs for sealing of the chamber to ground, and (ii) inclusion of the commonly used purging step for reduction of the initial headspace CO(2) concentration. The present modeling work provided insights into the effects on the delta(e) bias from retardation and partial chamber bypass of the soil CO(2) efflux. The results presented here supported the continued use of the static closed chamber method for the determination of delta(e), with improved control of the bias component of its measurement uncertainty.

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Section: The 3d Numerical Modelmentioning

confidence: 99%

Reduction of bias in static closed chamber measurement of δ¹³C in soil CO₂ efflux

Ohlsson¹

2009

Rapid Comm Mass Spectrometry

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Liposculpture of the aging face and neck

Habbema¹

2005

J of Cosmetic Dermatology

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Rejuvenation of the neck

Cited by 2 publications

References 1 publication

Reduction of bias in static closed chamber measurement of δ¹³C in soil CO₂ efflux

Reduction of bias in static closed chamber measurement of δ¹³C in soil CO₂ efflux

Liposculpture of the aging face and neck

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Rejuvenation of the neck

Cited by 2 publications

References 1 publication

Reduction of bias in static closed chamber measurement of δ13C in soil CO2 efflux

Reduction of bias in static closed chamber measurement of δ13C in soil CO2 efflux

Liposculpture of the aging face and neck

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Product

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About

Reduction of bias in static closed chamber measurement of δ¹³C in soil CO₂ efflux

Reduction of bias in static closed chamber measurement of δ¹³C in soil CO₂ efflux