Awardees

• Supervised by Carine GUIVIER-CURIEN (IRPHE), Cécile BARON (IRPHE), Philippe LASAYGUES (LMA)

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. (...)

• Topic supervised by Martin BRANDENBOURGER (IRPHE) & Joel MARTHELOT (IUSTI)

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 adaptive 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.

• Topic supervised by Bruno LOMBARD (LMA)

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.(...)

• Supervised by Olivier BOIRON (IRPHE) & Audrey SORIC (M2P2)

The Research topic concerns the study of biofilm development dynamics in micro/milli fluidic labyrinth systems. In a context of increasing water stress and competition for water resources in agriculture, microirrigation systems have been recommended for several years. These systems enable greater efficiency of water supply at plot level, but this efficiency can be compromised quite drastically by the presence of nutrients and ions in irrigation water, particularly in the case of reuse of treated wastewater, which increases the possibility of biofilm development in drippers (...)

• Topic supervised by Antonin COUTANT (LMA) & Cédric BELLIS (LMA)

Metamaterials is now a rich and mature field of research, with a wide range of potential applications for mechanical waves. One can think of the possibilities in waveguiding, for instance to redirect seismic energy to a target location, or in isolation for soundproofing. These artificial materials usually rely on a given periodic structure, which gives the waves exotic propagation properties. A key question in this context is whether these properties are maintained in the presence of irregularities or defects. In the last decade, the field of topological wave insulators has emerged from analogies with electrons in metals, to realize wave guiding with strong robustness against defects1. Within this class of structures, a very peculiar one has been predicted called the Topological Anderson Insulator (TAI). In this type of structure, the waveguiding properties arise because of disorder, making it inherently robust to fabrication defects and imperfections (...)

The aim of this work is to carry out a global study from the rheological properties of microalgae suspensions to a microfiltration membrane process. The aim is to determine under which operating conditions the microalgae could break. The integrity of these microalgae suspensions is evaluated as a function of the operating conditions using X ray tomography, TEM and MEB. The complementary aspect of these techniques should allow the determination of average but also individualized information about microalgae.

The project is part of a collaboration between the laboratories, LMA, IRPHE, LAMPEA (Aix-en-Provence), CEPAM (Nice, Sofia Antipolis) and the LC2R (Draguignan). It concerns the characterization of human and animal bones for applications in archeo-anthropology (study of ancient and paleolithic funerary rites) and zoo-archaeology (study of conservation in taphonomy, and paleolithic strategies of subsistence by bone fracturing). There is a large literature on the identification of the physico-mechanical properties of different elements and portions of human or animal bones with a recent or short postmortem interval, but very few studies, other than densitometry, on prehistoric human or animal bones. It is a challenge for the acoustic engineering and paleo-archaeology communities to study these bones.

During the cold spray process, micron-sized particles are accelerated by a supersonic nozzle and projected onto a substrate for coating purposes. Due to their relatively large size in a high-speed turbulent flow, particle inertia plays a fundamental role in the process. A detailed knowledge of the gas/particle velocity fields is hence essential for the prediction of the particle deposition rate. This project aims to provide, for the first time in this flow, coupled gas/particle measurements by the use of twocolor particle image velocimetry.

This project aims to study the unsteadiness of Shock wave boundary layer interactions when the boundary layer does not reattach downstream. Based on an original experimental setup in supersonic flow, previous studies have shown that the separation shock unsteadiness does not exhibit low frequency unlike classical interactions but seems to behave like a low-pass filter and amplifier of the perturbations generated in the subsonic external flow. By means of acoustic control of the subsonic region, the response of the interaction to harmonic disturbances will be explored.

Proteus, one of the oldest cave-dwelling species, exhibits remarkable adaptations on several levels. The objective of this project is to highlight its auditory faculties by carrying out several measurement campaigns at the Theory and Experimental Ecology Station (SETE). Acoustic and vibration measurements will then be carried out on the site. At the same time, simulations will be developed from 3D images taken with a micro-tomograph in order to have a prediction tool.