Call for post-doctoral fellows at the Aix-Marseille Université IMI Institute

The institute finances up to three post-doctoral fellows for a maximum duration of 24 months (12 months + possible renewal of 12 months) starting in October 2023.

Acoustofluidics in the micro-environment of bone cells : assessment of mechanical stimuli 

Bone is a mechanosensitive living tissue subjected to constant remodeling in response to mechanical constraints. Bone remodeling is a skillful balance between the action of bone-forming cells (osteoblasts), and bone-resorbing cells (osteoclasts) orchestrated by bone-mechanosensing cells (osteocytes). However, this natural process is insufficient to address numerous bone disorders such as complex bone fracture or bone cancer, in which bone reconstruction must be assisted. As mechanical waves, ultrasound can provide additional local mechanical stimulation and potentially restore the balance of bone remodeling. (…)

Development of a Lattice Boltzmann Method (LBM)-based wildland fire simulator

Global warming was found to enhance the frequency and severity of favourable weather conditions for widland fires in southern Europe, contributing to a lengthening of the fire
weather season as well as an increased frequency of days with elevated fire danger. In addition, although the term “mega fires” is not well defined and seems to be more appropriate to refer to extreme fires occurring in the US or in Australia, gobal warming effects have modified the wildland fire behaviour in Mediterranean regions, leading to fires of higher intensity, higher spread rate and more difficult to handle, especially at the Wildland Urban Interface (WUI) [1]. WUI defines areas where wildland vegetation intermingles with human settlements. In the current context of climate change, there is an increasing attention on the WUI since these areas are often considered as one of the main drivers of fire risk, as witnessed in the recent tragic fire events (115 deaths in Portugal, 2017 and 102 deaths in Greece, 2018). During these events, most deaths have resulted from suffocation at home or on the road due to the conjugated effects of an exposition to a large amount of smoke particles, extreme thermal radiation emitted by the fire and convection due to hot gases (…)

Hydrodynamics and transport of a solute in the presence of semi-permeable walls in a Taylor-Couette cell.

Membrane separation techniques, used to separate the constituents of a mixture by driving it through a semi-permeable membrane, are ubiquitous in industry (wastewater treatment), medical sciences (dialysis) or environmental  issues (desalination). They suffer from the accumulation of the retained materials near or inside the membrane, which deteriorates their performances, due to various mechanisms such as adsorption, scaling, osmotic pressure or the build up of a gel layer. These mechanisms remain poorly understood, as they are numerically difficult to model and occur near opaque membranes hindering optical measurement techniques. These mechanisms also impact the hydrodynamics at stake in the separation devices. Reciprocally, these mechanisms can also be used to act upon and abate accumulation, by promoting hydrodynamic instabilities for instance.
This Post-Doc position endeavors to address these phenomena in a Taylor-Couette cell, where brine is driven in the gap between a semi-permeable rotating inner cylinder and a clear impermeable fixed outer cylinder (…)

Interaction between a vortex and a fluid interface

Fluid vortices in environmental and engineering flows exist over a large range of scales, from huge tornadoes, through tip vortices in the wake of turbines, to the smallest eddies in turbulent regions at dissipation scale. Many situations involve vortical flows in which several immiscible fluids are present. They include floating bodies or bodies immersed at small depth which shed vortices under the water surface, or propellers and foils in the wake of which tip vortices may cavitate or simply trap atmospheric air into their core. In these instances, the presence of a liquid/gas interface located either in the vicinity of the vortex or within its core, significantly modifies its dynamics. Fundamental studies on the interplay between vorticity and interfaces are rare. The work proposed will investigate the interaction of a single fluid vortex and a liquid/gas interface in various configurations through theoretical/numerical modelling and stability analyses (…)

Mechanisms of plasma enhancement of molecular adhesion

This project proposes to improve the adhesion technique to improve the adhesion of optical quality silica assemblies. This requires an understanding of the impact of substrate preparation, polishing technique, as well as surface preparation by plasma which can improve the adhesion procedure and then the adhesion, microelectronics techniques, in order to increase the mechanical strength of hybrid structures. The development of a multi-scale model (from the atom to the structure), thanks to the multidisciplinary expertise (optics, physics, mechanics, materials) of the consortium, in order to open the way to a fundamental research and a methodology applicable to current optical materials. Under certain conditions, the methodology could also be applied to metallic assemblies. (…)

Self-contracting vascular solids

Inspired by nature, pneumatic soft robots use vascular networks and external pumps to twist, deform, move and bend in ways that traditional hard robots cannot. So far, these soft robots lack autonomy compared to organisms, which control fluid transport in vascular networks in much more advanced ways. From animals to fungi, one of the most efficient fluid transport mechanism is based on vessels that can actively contract upon local sensing of stimuli. This adaptative fluid transport enables advanced functionalities in organisms such as autonomous locomotion toward objectives. The main goal of the proposed research is to design self-contracting vascular networks to study active solids that deform upon sensing.(…)

WTDI – Elastic waves in metamaterials with time-modulated interfaces

By structuring materials, it is possible to control waves and obtain surprising effects: high-resolution lenses, directional antennas, invisibility cloaks, etc. This is the paradigm of metamaterials, a field of research that has been very active since the early 2000s and which promises many technological developments, for example improving Wi-Fi coverage or insulating buildings against seismic waves. However, the properties accessible with these materials also have limits, given by the usual laws of physics. Reciprocity is one of these laws [4]. In the linear regime and without flow, a wave transmitted between two points remains the same when the source and receiver are interchanged. Breaking the reciprocity makes it possible to control the waves in a novel way by making directional band gaps possible. Applications include wave filtering, diode design and logic gates in elastodynamics.(…)