Collective motion of self-sustained swarming flows has recently provided examples small-scale turbulence arising where viscous effects are dominant. We report the first observation universal enstrophy cascade in concentrated sperm consistent with a body evidence built from various independent measurements. found well-defined ${k}^{\ensuremath{-}3}$ power-law decay velocity field power spectrum and relative dispersion small beads theoretical predictions 2D turbulence. Concentrated living...

The electrohydrodynamic thrust generated by wire–cylinder electrodes under high dc voltage is experimentally analyzed. Some recent experimental studies have shown that thrusters produced corona discharge and ionic wind are able to deliver thrust-to-power ratio, which reopens prospects for propulsion. From simple considerations based on ultralight aircraft mass, aerodynamics, battery densities, their potential applications showcased. Furthermore, an study performed, the observations presented...

We studied normal and tumorous three-dimensional (3D) microvascular networks in primate rat brain. Tissues were prepared following a new preparation technique intended for high-resolution synchrotron tomography of networks. The resulting 3D images with spatial resolution less than the minimum capillary diameter permit complete description entire vascular network volumes as large tens cubic millimeters. structural properties investigated by several multiscale methods such fractal...

Summary This paper presents the first application of high‐resolution X‐ray synchrotron tomography to imaging large microvascular networks in biological tissue samples. technique offers opportunity analysing full three‐dimensional vascular network from micrometre millimetre scale. specific sample preparation method and procedure. Either barium or iron was injected as contrast agent network. The impact composition concentration solution on images has been studied. Two modes, attenuation phase...

New experimental evidence of self-motion a confined active suspension is presented. Depositing fresh semen sample in an annular shaped microfluidic chip leads to spontaneous vortex state the fluid at sufficiently large sperm concentration. The rotation occurs unpredictably clockwise or counterclockwise and robust stable. Furthermore, for highly concentrated semen, richer dynamics can occur such as self-sustained damped oscillations. Experimental results obtained with systematic dilution...

White and brown adipose tissues play a major role in the regulation of metabolic functions. With explosion obesity disorders, interest adipocyte biology is growing constantly. While several studies have demonstrated functional differences between fat pads, especially their involvement diseases, there are no data available on possible heterogeneity within an depot.This study investigated three-dimensional (3-D) organization inguinal pad adult mice by combining tissue clearing autofluorescence...

We analyze the problem of geometrical aperture between two faces a crack described as self-affine surface. consider contact surfaces after relative rigid-body displacement (translation and/or rotation) one side with respect to opposite one. A number properties are obtained analytically and illustrated by numerical simulations on generated surfaces. The results concern scaling average aperture, which is shown include very slowly varying correction term (logarithmic displacement); this affects...

This paper describes the use of a new 3D high-resolution imaging technique dedicated to functional vessels for systematic quantitative study angiogenesis in primate cortex. We present method which permits, using synchrotron X-ray micro-tomography imaging, identification micro-vascular components as well their automatic numerical digitalization and extraction from very large image analysis post-treatments. is used analyze various levels organization postnatal modifications. Comparing newborn-...

We report new results on blood flow modeling over large volumes of cortical gray matter primate brain. propose a network method for computing the flow, which handles realistic boundary conditions, complex vessel shapes, and nonlinear rheology. From detailed comparison available models rheology phase separation effect, we are able to derive important impact structure pressure, hematocrit, distributions. Our findings show that geometry (vessel shapes diameters), conditions associated with...

We present a new algorithm which merges discontinuities in 3-D images of tubular structures presenting undesirable gaps. The application the proposed method is mainly associated to large microvascular networks. In order recover real network topology, we need fill gaps between closest discontinuous vessels. presented this paper aims at achieving goal. This based on skeletonization segmented followed by tensor voting method. It permits merge most common kinds found robust, easy use, and...

Particle image velocimetry of ionic wind produced by a positive dc corona in air is used to evaluate lift force, and results are consistent with general theoretical expression previously found for net momentum transfer. Momentum transfer efficiency be sensitive the electrode aerodynamic wake electric field orientation.

Numerical methods generally need analytical solutions as test cases and validations in simplified problems. This work provides Laplace-domain explicit analytic for fluid–structure interaction (FSI) water hammer waves within a pipe. Rather than applying the transfer matrix method (TMM) to FSI four equations, it is transposed equivalent two-wave propagating problem considered instead. Using classical wave diagonalization approach permits decoupling waves' propagation while at same time...

The classical positive Corona Discharge theory in a cylindrical axisymmetric configuration is revisited order to find analytically the influence of gas properties and thermodynamic conditions on corona current. matched asymptotic expansion Durbin Turyn [J. Phys. D: Appl. 20, 1490–1495 (1987)] simplified but self-consistent problem performed explicit analytical solutions are derived. mathematical derivation enables us express new DC current-voltage characteristic, choosing either...

Abstract Adipose tissue, as the main energy storage organ and through its endocrine activity, is interconnected with all physiological functions. It plays a fundamental role in homeostasis development of metabolic disorders. Up to now, this tissue has been analysed pool different cell types very little attention paid organization putative partitioning cells. Considering absence complete picture intimate architecture large soft we developed method that combines clearing, acquisition...

Transport of deformable particles in a honeycomb network is studied numerically. It shown that the particle deformability has strong impact on their distribution network. For sufficiently soft particles, we observe short memory behavior from one bifurcation to next, and overall consists random partition exhibiting diffusionlike transport. On contrary, stiff enough undergo biased whereby they follow deterministic at bifurcations, due long memory. This leads lateral ballistic drift small...

A linear stability analysis is presented for the Kelvin–Helmholtz instability in a Hele-Shaw cell, an based on Navier–Stokes equation to improve previous Euler–Darcy study that Gondret and Rabaud [Phys. Fluids 9, 3267 (1997)] made of their own experiments.

The effects of lubricant film flow, pressurized and sheared between two parallel sinusoidal wavy surfaces in sliding motion is studied analytically. Results are presented using a flow factor model which provides an average description the roughness impact. Two distinct cases order to compare stationary or time dependent local aperture configurations. Flow factors computed respectively for each case through spatial spatio-temporal average, revealing striking differences. results shed light on...