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ptc-17268891-Visitor
1-Visitor
March 4, 2010
Question

Measuring surface area of multiple cycles

  • March 4, 2010
  • 2 replies
  • 3229 views
Dear All,

We are analyzing data of gas pressure in a balloon during inflation and deflation. We measure during 20 s. We are interested in calculating the positive and negative surface area of the pressure curve. Till now we manually isolated one cycle, split it into the positive and negative part and subsequently calculate surface area. I wonder if it is possible to detect the positive and negative parts of the curve automatically so that we have a more representative situation than just relying on one manually chosen cycle.
Any help would be appreciated.

Filip

2 replies

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Fred_Kohlhepp23-Emerald I
23-Emerald I
March 4, 2010
It occurs to me that your plot must cross zero to transition between positive areas and negative areas. Solving for the roots, then (the zero crossings) would determine the limits of integration.


Fred Kohlhepp
fkohlhepp@sikorsky.com
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ptc-17268891-VisitorAuthor
1-Visitor
March 8, 2010
Thank you Fred for the hint. I can strip the upper and lower part from the curve by using an "if" function. But I would like to sort then each cycle into a vector and subsequently through a program calculate the surface area of each cycle. Unfortunately I am not an engineer nor do I have much programming experience so any help would be highly appreciated.
F
Fred_Kohlhepp23-Emerald I
23-Emerald I
March 19, 2010
please save back to version 11

Fred Kohlhepp
fkohlhepp@sikorsky.com
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ptc-17268891-VisitorAuthor
1-Visitor
March 20, 2010
Dear Fred,

I am glad the collaboratory is finally working again. I have attached the file in MC11 format you can leave it in MC11 as I have both 11 & 14.
I appreciate your help

Filip
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