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posted by martyb on Thursday January 13, @01:44AM   Printer-friendly
from the To-see-a-world-in-a-grain-of-sand-and-corn-dancing-on-a-stove dept.

Some dynamic systems can develop multi-periodicity, meaning that some parameter, such as a mechanical oscillation, can switch between different vibrational frequencies or amplitudes. For instance, a small-scale disturbance is coupled into a large-scale one.

This has been observed in muscle motion, laser stability, seismic motion, etc, and there is much to understand about these couplings in chaotic systems. Initiated by an apparent diversion from pandemic boredom, Promode Bandyopadhya noticed that when shucked cobs of corn were placed on a glasstop hotplate, the cob oscillates autonomously about three axes with varying amplitudes and frequencies that shifted randomly with time. He videoed ears of corn as well as a number of other smooth fruits on a hot surface and extracted their motion over time. His results are summarized in a tour de force of mechanical dynamics in a Nature Scientific Reports paper. He observed that corn cobs roll, pitch, and yaw, but green chilies, blueberries, tropical berries, red grapes, oblong grapes and grape tomatoes only roll and yaw.

Autonomous thrust oscillations are difficult to design in a laboratory, however we have discovered that the seven types of fruit offer a new test bench.

Details and videos of his dynamical systems kitchen laboratory observations are provided as a Google Drive Link.

Journal Reference:
Promode R. Bandyopadhyay. Multistable autonomous motion of fruit on a smooth hotplate [open], Scientific Reports (DOI: 10.1038/s41598-021-03859-8)

Original Submission

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  • (Score: 0) by Anonymous Coward on Thursday January 13, @10:56AM (4 children)

    by Anonymous Coward on Thursday January 13, @10:56AM (#1212385)

    What is the jist here?
    That objects, [fruits], have a natural periodicity which is modified accordingly when placed on a hot seat?
    Sounds like what happens when politicians and business types get hauled before congress.

    Seriously though, what are we looking at here and is there a practical application of this finding or is this just some piece of the chaos puzzle theorem?

  • (Score: 4, Interesting) by hubie on Thursday January 13, @02:06PM (3 children)

    by hubie (1068) on Thursday January 13, @02:06PM (#1212407) Journal

    I can't really answer the practical application part, but it ties directly into the dynamics of nonlinear systems research. I have to admit that the initial thing that caught my eye was the title. I like to idly peruse journal papers and a good deal, if not most of them have titles that are incomprehensible to me because they are so specialized. But sometimes you get one where you look at the title and you think "it can't really be about that, that sounds like they're grilling fruit!" and it turns out it is! Those are my favorite kinds of papers to read in a journal like this (as opposed to something like The Physics Teacher kind of journal where you wouldn't be surprised to see something like that). Then once I looked at the paper and saw that it was not only experimental, but done in his kitchen and done very thoroughly, that really appealed to me (I've done similar things myself, but I've never published them in a Nature journal!). I just loved the fact that he was bored in lockdown, noticed interesting nonlinear behavior in his kitchen, and then did the whole experiment complete with video frame analysis, plus the mathematical treatment behind it is amazing. I probably should have been more explicit in the article summary to draw more attention to those aspects of it. This harkened back to the heyday of chaos research in the late 80s where all sorts of experiments at this level were being done.

    What this experiment is specifically getting at is demonstrating a simple multi-state system where behavior switches between states and the coupling of states. So something like a turbulent flow boundary where you have one behavior in one region and another in another region, and disturbances in one regime get coupled between the two. This point of this paper was showing that you don't necessarily need complex simulations done on supercomputers or elaborate setups to observe this behavior. I have to say that the thought of walking into a lab at a prestigous institution and seeing researchers standing around staring at blueberries grilling on a hotplate was very amusing to me.

    • (Score: 0) by Anonymous Coward on Thursday January 13, @05:21PM (2 children)

      by Anonymous Coward on Thursday January 13, @05:21PM (#1212444)

      I was thinking of an experiment for a Youtube video where you make a copy of a copy of a copy of a sheet of paper. I wanted to see what happens after, say, 100 copies of copies. I tried Youtube searching it and the only thing that comes up is some song. I'm surprised I can't find something like this and I'm too lazy to do it myself.

      It would also be interesting to see what happens if you use the same copier over and over with each copy vs using different copiers at various times. I imagine if you use the same copier each time (assuming you gave it some rest time) you would need more copies before it becomes blurry (font size 12 times new roman) since you are repeating the same imperfections of the same copier over and over and not introducing new varying imperfections from different copiers.

      If you use different copiers each copier will add different imperfections and it may take fewer copies before the text becomes difficult to read. I would like to see, more specifically, how it becomes difficult to read. Does it fade? Does it become blurry? How? Also make sure you don't use one of those copiers that tries to infer and reinsert letters/characters.

      This could be interesting in an office environment where there are multiple copiers and you need several copies of something so you quickly make copies of it on the nearest copier. The next time you or someone else needs several copies of it they take one of the copies and makes copies of that on the nearest copier at the time (perhaps using a different copier). What would happen over a long period time as you keep making copies of copies on various different copiers (vs if you just used the same copier). I suppose the quality would be at least as low as the lowest quality copier you use and would probably be lower over time.

      Yes, we are so bored we are rolling and laughing out yaws and pitching new low pitched dull ideas.

      • (Score: 0) by Anonymous Coward on Thursday January 13, @05:29PM (1 child)

        by Anonymous Coward on Thursday January 13, @05:29PM (#1212446)

        (Same poster: I'm not sure what those printers are called but I guess I'm going to call it an OCR reprint printer or whatever).

        • (Score: 3, Informative) by hubie on Thursday January 13, @07:35PM

          by hubie (1068) on Thursday January 13, @07:35PM (#1212493) Journal

          If I was asked to take a stab at guessing your age, I would put you at under-40. The reason being that the experiment you've described was common standard operating procedure in the 90s and earlier (well, not quantifying it). Actually, I'll say mainly the 90s when decent and relatively affordable copier machines were available, but before PostScript and PDFs took over. Before that, copies were made using photostats and mimeograph machines []. The quality of the first copy wasn't too bad (mimeographs were worse), but when you got into making copies from copies, it could get ugly fast. Probably my favorite example of this is the original Pons and Fleishmann cold fusion experiment announcement. The "preprint" for that exploded around the world, basically via fax machine. So institutions would receive a fax, then that would get re-faxed to N other places as well as M copies of it made, so you had faxes of faxes of copies of faxes, etc. I was in graduate school at the time and even I have a copy of that preprint somewhere. I recall my copy being pretty ugly too, with skewed pages and such. I also recall how exciting the news was at the time. It is really special to be in the right environment when something like that happens. I was also lucky to be in school when room temperature superconductors were announced.