# baltoche

Members

24

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• Rank
Quark

## Profile Information

• Favorite Area of Science
Electrical engineering
1. ## What is this function ?

Dear All, Thank you for your respective contributions. I do appreciate ! the reason why I need this function is because I need to integrate it in function of x. Have your codes been typed on Matlab ? Do I need module "Symbolic Math Toolbox" to try your code ? Thanks again and Regards, Cédric
2. ## What is this function ?

Dear All, I'm trying to find function J(x) shown in attached file. Could somebody help me ? It seems that I don't have the right tool to solve it Thanks and Regards. Série.pdf
3. ## Electrical resistivity in finite elements

Well caught, thank you very much for your support from the beginning. I'll not be involved myself into finite elements, but an engineering student will dot it for me. I've got a licence of CST, do you know this tool ? One last question please : have you got any opinion on the resistor value of my cube edges ? Kind Regards.
4. ## Electrical resistivity in finite elements

Do you know if Comsol also deals with electrical fields ? Is it a freeware software ?
5. ## Electrical resistivity in finite elements

Oh I see, thanks ! Do you personally use these tools, and especially the circuit simulation one ?
6. ## Electrical resistivity in finite elements

I'll try this, thanks. But is Octave-Forge somehow related to Matlab or not ?

8. ## Electrical resistivity in finite elements

Dear All, Suppose I've got a medium (like a soil) of a homogeneous and constant resistivity Rho (in Ohm.km). This medium is put into a big cube of 1km side, then giving a km3 of my medium. Now suppose I want to model my cube by an electrical circuit with resistors at each side of the cube. May I state that each resistor will be Rhox4 then ? No suppose I divide my km3 into equal 8 cubes of 500m side each and suppose I still want to model this arrangement by electrical resistors. What should be the value of each resistor/side then if I need that the whole set still corresponds to a resistivity of Rho ? I propose Rhox9/2. Am I right ? For these who know Matlab, can Matlab simulate this kind of 3-D electric circuit with cubes whose sides are resistors ? Is there any special module to perform this function ? Thanks to All.
9. ## Cymegrid

Dear All, Does somewhat know this software well ? I'm trying to get potentials in the ground but below the surface of the soil, and what I only managed to get so far are potentials on the soil surface. This does not surprise me since this software is intended to calculate step and touch potential for people staying or walking ON the soil, and not for dead people buried in the ground... If Cymegrid cannot achieve this, would CDEGS do the job ? Thanks.
10. ## Electrical propagation in a non uniform soil

Hello Studiot, Please find attached a sketch, where 3 soil layers have been represented. A current is impressed in P and the goal is to determine the potential of points M1, M2 and M3 with respect to far earth. If my purposes are not clear, please get back to me. Kind Regards. 3 layers.pdf
11. ## Integral

Hello Studiot, Thanks for your kind contribution. Ideally, I'm after a function of A in order to plot it, knowing that I know between what values (O and Pi) I need to integrate this function. Actually, I asked for the primitive in order to calculate the integral, which is also a function of A, and this is the one I'd like to plot. For your information, this primitive/integral is needed too solve Bessel's equation and function. I'm sorry for the poor quality of my English. Kind Regards.
12. ## Integral

I know the values between whom I need to integrate this function, but it does not solve my issue... Regarding numerical methods (calculating a rough surface for instance), I cannot do it since my final integral will be a function of A. If the answer is not an elementary function, is there a way to approach it ? Thanks in advance.
13. ## Electrical propagation in a non uniform soil

Good evening, To Studiot : As fas as electrodes are concerned, my current is impressed by several voltage sources located at different places on a conductor that is laid down the soil. Currents leak from this conductor. Therefore, there are several electrodes. I'll put a sketch later on. To RiceAway : thanks for your contribution. My purpose is not to measure the soil resistivity, but to assume several layers (with their respective resistivity's and thicknesses) of soil and from this assumption, calculate the potential of a point P in the soil depending on its relative location with respect to the injection, and of course depending on the characteristics of the soil layers that are mentioned above. With border conditions, I've come to Bessel equation and functions, but I'm not sure it is the best way to proceed... Regards.
14. ## Integral

Dear All, I'm trying to find a primitive of f(x)=cos(-Asin(x)) where A is a constant number. I've tried Wolfram but unsuccessfully. An approximate function of this primitive would also be welcome. Thanks for your help ! Kind Regards.
15. ## Electrical propagation in a non uniform soil

Dear All, I would enjoy your help on electrical geophysics . Suppose a soil divided into 3 layers, each of them having a different electrical resistivity (Rho1, Rho2 and Rho3, starting from the top to the bottom) Now suppose a dc current injection from a point M located at the top surface of the soil. This injection is vertical, going from the top (surface of the soil) to the bottom. My purpose is to assess the electrical potential (with respect to far earth) of a point P (coordinates : x, y and z with respect to point M) depending on the injected dc current, the coordinates of P, and the 3 soil resistivities. I've come to Bessel equations and functions, but there may be a more simple way to proceed. Any light on my concern please ? Thanks and Regards.