ZMT zurich med tech

@ofli Can the conductivity map after head segmentation be exported?

I want to see the impact of different grid sizes on the simulation, so I cloned a pair of simulations and modified the maximum step size of the grid. However, I found that if I create a new pair of simulations using the same settings, the grid sizes, simulation durations, and results of the new simulations and the cloned simulations are all different. Why does this happen?

Assuming a linear relation between voltage and pressure amplitude, you should be able to map the input voltage to the input pressure (I think its 1 MPa by default), and then use this as a scaling factor, but it's unclear to me what you mean with voltage at the focused area. What exactly do you mean by transducer sensitivity? You could run additional simulations where you shift the transducer or slightly change some parameters to get a sense of the sensitivity.

Great! Goit it, thank you so much. One last question regarding where the simulation outputs are located and saved. The coordinates of the voxelized entities where can be found? Thank you so much for your time :)

@bryn Thanks, I found it!

Hi @tayjiekai sim4life.lite is the student version of our online simulation platform sim4life.science and comes with certain limitations. As indicated by the error message, it does not support a number of neurons exceeding 10. If the limitations of sim4life.lite are too restrictive for your work, I suggest transitioning to the full Sim4Life web version at sim4life.science.

Hi, you can get additional information by enabling the "Far Field" sensor and then choosing the "Radiation Report" evaluator (see for example the Phased Array Patch Antenna tutorial). It will not solve your problem, but might help you get a clearer picture. From what you describe, it's possible you have a very low mismatch efficiency (most of the energy is reflected). This could be addressed by improving the way you are modeling your source, or by just ignoring it if it is not important (i.e. if you are not actually simulating the real feed and are only interested in the antenna itself). You would do that by considering the Radiation Efficiency (ratio of Radiated Power to Accepted Power) instead.

Hello! Thank you for your quick answer :) I'll do that in the meantime

Joule heating sources from various processes (e.g., EM energy deposition by ohmic losses) can be considered as inhomogeneous heat sources in thermal simulations. To create heat sources Simulation Link: Sensor settings of an EM FDTD simulation in the same project can then be dragged and dropped into Source Settings folder. Modulated Analysis/Cache: Data Origin Type can be defined as: (a) Cache File: select the path of a thermal source previously exported into a .cache file. (b) Analysis Output: select the energy density of interest directly from the Analysis. You can look into the heated brain tutorial for a simplified example.

found my own answer: [image: 1730811141668-a0bbc3ce-5488-4bea-8af6-95ae9439824b-image.png]

Hi, There is most likely an error due to a sanity check, since you appear to have lossy tissues in your simulation and the Magneto Static Vector Potential solver does not account for those losses. Having a ferrous core, however, you do need to use that solver. The trick is to chain 2 simulations: one that solves the magnetic vector potential (A), and one that uses this A as a source term to determine the induced electric field (this time accounting for losses). The key is to remove the lossy tissues from the first simulation (only metallic or ferrous materials play a role anyhow). I would recommend you have a look at the LF tutorial called "Wireless Power Transfer: Exposure Assessment", since it uses the same technique. In addition, it seems that "The solver may have run out of RAM"... I would therefore check the RAM usage to make sure it's not going beyond your resources. Note that using the technique above allows you to have two different resolutions: one optimized to properly resolve the coil, the other to resolve the tissues (as long as the domain sizes of the first simulation is large enough to include that of the second). This usually leads to smaller grid sizes, thereby reducing the RAM usage...

Hi, Please allow me to share here the response we sent you via the Sim4Life support email so that other users can benefit from your questions. The default machine provides 500GB of storage, and you are running out of space for this project. If your results require more than 500GB, consider upgrading to a higher-tier machine with greater storage capacity. Alternatively, you could reduce the size of your simulation project by splitting it into multiple smaller simulations. This would allow you to continue using the default tier. Additionally, you might optimize your sensor settings, such as by creating smaller sensors and recording data for specific volumes of interest, rather than using an Overall Field sensor.

@Sylvain Yes thanks finally I succeed!

Hi Andrei, I replied on the other thread: https://forum.zmt.swiss/post/1941