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FDTD, Low-Frequency, Neuron, Mode-Matching, Flow, Acoustics, etc...

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  • FDTD, Low-Frequency, Neuron, Mode-Matching, Flow, Acoustics, etc...

    11 Topics
    27 Posts
    N

    Hi! Can someone help me understand if it makes sense to calculate SAR statistics in a low frequency electrical stimulation (30 Hz)? Thanks!!

  • What is the mismatch efficiency?

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    SylvainS

    @rose your simulations are most likely done with a 1V voltage at the excitation source (that's the default setting). This is perfectly fine from a numerical point of view, but in practice (e.g., if you wanted to compare with measurements) you probably want to normalize your results. In the Far Field Sensor, for example, you can normalize to a Total Available power of 1W (say). This way, you will be comparing apples to apples.

    That will not change the value for the Gain, though (since it is a power ratio, independent of scaling). This must come from either a difference in some aspect ratio of your dipole, or simply that you did not change the dimensions in the same proportion (1/10th) as you changed the frequency.

  • This topic is deleted!

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  • Something that's bothering me

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    L

    I would double-check that the electrodes being used are added as voxels correctly if they're not then the boundary conditions do not get set up properly.
    It might be easier to help if you provide more information.

  • Can I make the animation of radio waves(EM E(x,y,z,f0))?

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    R

    @Sylvain It really helped!! I've successfully done making animation!! Thank you for helping me.

    Since you also gave me some advice about TRP problems, I would like to carry on the solutions you suggested. I really appreciate your help.

  • Why TRP exceed input power

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    A

    duplicate of (https://forum.zmt.swiss/topic/337/why-does-trp-exceed-input-power-antenna)

  • Axon getting stimulated even with atto Amps of current !!

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    S

    @habib

    Hi,

    Thank you for your reply.

    I can understand that if you enable the titration, the software keeps on scaling the field till sees a stimulation. But it also gives us a number for the scaling field. In this case, I am seeing that number to be 0.13.

    Doesn't it mean that the field has been scaled down to a factor of 0.13 to create the minimum field for stimulation - I was hoping that number to be orders of magnitude higher.

    Please correct me if I am wrong.

    Thanks for looking into this.

  • Simulating a bipolar electrode with contant power

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    SylvainS

    Hi,
    There is a tutorial called "Parallel Plates" for the LF (low-frequency) solver. I think it does exactly what you need. You can access the step-by-step instructions from Sim4Life -> Help -> HTML Tutorials -> 3.2.1. Parallel Plates
    You can also open the Sim4Life project using Sim4Life -> File -> Open Tutorial -> EM LF Tutorials -> Parallel Plates.smash

  • 2 Coils: Single or multi port?

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    S

    Hi Ari,
    It depends on your purpose.
    If you use single port simulation, then, you cannot later change the phase difference between the coils. However, if you use multiport simulation, Sim4Life runs 2 simulations for each coil and stores the results separately. This is useful if you would like to postprocess results for different source parameters. For example, you may change the current amplitudes for each coil, or add phase differences. You do not have to run the simulations again. New results will be directly calculated by using the previously stored multiport results.
    So, if you have enough memory and would like to try different settings for the sources, you had better to use multiport simulation for the above setup.
    If you want to save time and memory and fixed the source settings, then you may chose single port simulation.

    I hope this helps.
    Sayim

  • Simulating with different materials.

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    L

    The easiest way I found is to use the power (I=P/V) as it shows you the current lost in different parts of the model as well as overall. have a look at what was mentioned here https://forum.zmt.swiss/topic/24/compute-the-total-current-flowing-between-two-electrodes-in-an-electro-quasistatic-lf-simulation/3?_=1618565314728

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    D

    @lj I have followed the yoon-sun arm stimulation tutorial, but I don’t understand the meaning of the results obtained. I don’t know the relationship between these results and tactile feedback, nor can I understand how to get information about tactile sensation and nerve fiber potential. Information link.

  • who can tell me what is the wrong

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    D

    thank you bro,I have found what the wrong ,I have simulated too many times, causing the D drive to run out of space. I cleaned it up and the problem was solved.

  • How to define user defined source in Neuron solver?

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    K

    https://forum.zmt.swiss/topic/175/user-defined-waveforms

    Linked thread illustrated the exact solution for the above problem.

  • simulation failed

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    AntoninoMCA

    @daolin_qu Could you please check that you are selecting the Nerve_ventral_root_spinal_T1_Brachial_plexus_ulnar_right_6 spline entity and not the nerve itself that instead is a surface mesh entity part of the anatomical body? Thanks!

  • Yoon-sun Arm Neural Sensing case neuron does not work

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    AntoninoMCA

    @daolin_qu From the image you posted, I see that you haven't yet load the model, that's why you cannot run yet a simulation. You can do that by clicking on the 'Load Model' icon in the top panel. After that, you can assign sensors and run the simulation.
    The 'Load Model' initiates the discretization of the axon trajectory into compartments (electric circuits describing the electrophysiology of the specified axon model, i.e. SENN).

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    J

    @sayimgokyar Thank you for the clear answer. I get it now.

  • How to choose between EM LF ELECTRO and Magneto

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    S

    Scaling method ref. Furse C M and Gandhi O P1998 "Calculation of Electric Fields andCurrents Induced in a Millimeter-Resolution Human Model at 60 Hz Using the FDTD Method" Bioelectromagnetics 19:293–299 (1998)

  • Evaluating sim4life for tDCS

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    H

    what is ARMA?

    FDTD is not adequate for any simulations where the wavelength is long compared to the object being modeled

    https://speag.swiss/products/semcad/modules/what-is-fdtd/