arXiv subjects

Yann Bouret

Publications and source records attributed to Yann Bouret.

3 recordsLinked to original sources

arXiv2024

Receding contact line dynamics on superhydrophobic surfaces

We have explored receding contact line dynamics on superhydrophobic surfaces, composed of micropillars arrays. We present here dynamic receding contact angle measurements of water on such surfaces, covering contact line speeds spanning over five decades. We have studied the effect of pillars fraction on dynamical receding contact angles. We compared these measurements to those on smooth surfaces with the same chemical nature and also with similar systems reported in the literature. We show that superhydrophobic surfaces exhibit a significantly lower dependence of contact angle on contact line speed compared to smooth surfaces. Additionally, we observed that a higher surface fraction of pillars leads to a greater dependence of the contact angle on contact line speed, approaching the dependence of the angle on smooth surface. Interestingly, we show that the exact texuration of the surface does not play a fundamental role in the angle-velocity relationships as long as microtextures present the same type of periodic pattern (pillar arrays or microgrid). These results are interpreted in terms of viscous friction reduction on superhydrophobic surfaces, shedding light on the underlying mechanisms governing their unique dynamic behavior. In addition we show that contact angles follow same laws for two different geometries (milimetric sessile drop and a centimetric capillary bridge).

cond-mat.soft↗

arXiv2015

Bootstrap and permutation tests of independence for point processes

Motivated by a neuroscience question about synchrony detection in spike train analysis, we deal with the independence testing problem for point processes. We introduce non-parametric test statistics, which are rescaled general $U$-statistics, whose corresponding critical values are constructed from bootstrap and randomization/permutation approaches, making as few assumptions as possible on the underlying distribution of the point processes. We derive general consistency results for the bootstrap and for the permutation w.r.t. to Wasserstein's metric, which induce weak convergence as well as convergence of second order moments. The obtained bootstrap or permutation independence tests are thus proved to be asymptotically of the prescribed size, and to be consistent against any reasonable alternative. A simulation study is performed to illustrate the derived theoretical results, and to compare the performance of our new tests with existing ones in the neuroscientific literature.

math.ST↗

arXiv2015

A Distribution Free Unitary Events Method based on Delayed Coincidence Count

We investigate several distribution free dependence detection procedures, mainly based on bootstrap principles and their approximation properties. Thanks to this study, we introduce a new distribution free Unitary Events (UE) method, named Permutation UE, which consists in a multiple testing procedure based on permutation and delayed coincidence count. Each involved single test of this procedure achieves the prescribed level, so that the corresponding multiple testing procedure controls the False Discovery Rate (FDR), and this with as few assumptions as possible on the underneath distribution. Some simulations show that this method outperforms the trial-shuffling and the MTGAUE method in terms of single levels and FDR, for a comparable amount of false negatives. Application on real data is also provided.

stat.AP↗