Can self-propelled objects escape from compression stimulation?
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 38567457.
- Also identified by DOI 10.1039/d4sm00288a.
- No licence information is recorded for this record.
- Because redistribution is not established, this page shows the abstract only. Follow the links below for the full text.
Abstract
We studied circular papers impregnated with camphor (CPs) and CPs with magnets (MCPs) as self-propelled objects floating on water under the compression of the water surface as an inanimate system for evacuation in an emergency. Two water chambers-C<sub>in</sub> and C<sub>out</sub>-were connected <i>via</i> a plastic gate, and eight CPs or eight MCPs were placed on C<sub>in</sub>. We monitored the movement of the CPs or MCPs from C<sub>in</sub> to C<sub>out</sub> when the gate was opened and the area of C<sub>in</sub> (<i>A</i><sub>in</sub>) was decreased using a barrier. When <i>A</i><sub>in</sub> was large, CPs moved stochastically from C<sub>in</sub> to C<sub>out</sub> while exhibiting random motion. The escape probability from C<sub>in</sub> to C<sub>out</sub> (<i>P</i>) at time <i>t</i> = 20 s increased with a decrease in <i>A</i><sub>in</sub>, and the rate of increase in <i>P</i> increased depending on the width of the gate (<i>W</i><sub>g</sub>). By contrast, clustering was observed for MCPs. Consequently, <i>P</i> of MCPs was lower than that of CPs. The difference in the surface tension between C<sub>in</sub> and C<sub>out</sub> (Δ<i>γ</i>) increased with a decrease in <i>A</i><sub>in</sub>. <i>P</i> is discussed in relation to Δ<i>γ</i> as the driving force for emergencies and the repulsive forces between CPs or attractive forces between MCPs. These results suggest that the repulsive force enhances the self-propulsion of objects towards the gate, that is, as a result, higher values of <i>P</i> are obtained.