The shape of impacting drops onto a solid surface is investigated by probing the local flow velocity and the local thickness profile of the spreading lamella during the drop impact. First, as a model ...situation of no viscous coupling between the liquid and the substrate, the impact of a drop onto hot plates, above the Leidenfrost temperature, is considered. In this case, we demonstrate that the velocity and thickness profiles are in good agreement with inviscid convective flow theory. This local description allows us to revisit the modelling of well-studied global behaviour such as drop spreading. Building from this idealized situation, viscous boundary-layer effects emerging from frictional coupling on a cold surface are then captured.
In this article, we describe some aspects of the diffuse interface modelling of incompressible flows, composed of three immiscible components, without phase change. In the diffuse interface methods, ...system evolution is driven by the minimisation of a free energy. The originality of our approach, derived from the Cahn–Hilliard model, comes from the particular form of energy we proposed in Boyer and Lapuerta (M2AN Math Model Numer Anal, 40:653–987,2006), which, among other interesting properties, ensures consistency with the two-phase model. The modelling of three-phase flows is further completed by coupling the Cahn–Hilliard system and the Navier–Stokes equations where surface tensions are taken into account through volume capillary forces. These equations are discretized in time and space paying attention to the fact that most of the main properties of the original model (volume conservation and energy estimate) have to be maintained at the discrete level. An adaptive refinement method is finally used to obtain an accurate resolution of very thin moving internal layers, while limiting the total number of cells in the grids all along the simulation. Different numerical results are given, from the validation case of the lens spreading between two phases (contact angles and pressure jumps), to the study of mass transfer through a liquid/liquid interface crossed by a single rising gas bubble. The numerical applications are performed with large ratio between densities and viscosities and three different surface tensions.
This paper presents the dynamic modeling of a continuous three-dimensional swimming eel-like robot. The modeling approach is based on the "geometrically exact beam theory" and on that of ...Newton-Euler, as it is well known within the robotics community. The proposed algorithm allows us to compute the robot's Galilean movement and the control torques as a function of the expected internal deformation of the eel's body
Habitat changes induced by restoration can favour invasive species, thereby thwarting the main biological objectives of restoration and possibly limiting a project’s success. Here, we focus on a ...study site located along the Old Rhine River that was being restored in 2013 by controlled bank erosion and implementation of artificial transverse groynes. In the Upper Rhine (Franco-German border), the first reports of the bighead goby (
Ponticola kessleri
, Günther 1861) and round goby (
Neogobius melanostomus
, Pallas 1814) were 2010 and 2011, respectively. As the round goby largely dominates the overall goby assemblage, we asked about the consequences of its presence on the restored site. Electrofishing was carried out from 2013 to 2021 in parallel to a benthic macroinvertebrate monitoring conducted from 2014 to 2019. In 2015/2016, we looked at goby’s predation by studying their stomach contents through macroscopic visualisation and eDNA metabarcoding analysis. For results, gobies were found in large densities dominated by
N. melanostomus
, increasing over time to the detriment of local fish species. No predation was observed on native fish species but
N. melanostomus
cannibalism reached 9%. Round goby’s predation was opportunistic, based on the most abundant benthic macroinvertebrates: (i) low trophic level taxa, and (ii) invasive amphipod crustaceans. If round gobies fed on some insects, they did not prevent the colonization of new taxa on the habitats that appeared after restoration. We stress that the high abundance of
N. melanostomus
has led to profound changes in the food web structure and species interactions in the Old Rhine River, but it is unlikely that it masked the restoration consequences on macroinvertebrates 6 years after the restoration. These results support (i) the importance in carrying out long-term monitoring to confirm that a stronger trophic impact is not ultimately delayed, and (ii) the diversification of habitats as an option for limiting the invasion by gobies.
In this paper, we present a unified dynamic modeling approach of (elongated body) continuum robots. The robot is modeled as a geometrically exact beam continuously actuated through an active strain ...law. Once included in the geometric mechanics of locomotion, the approach applies to any hyperredundant or continuous robot that is devoted to manipulation and/or locomotion. Furthermore, by the exploitation of the nature of the resulting model of being a continuous version of the Newton-Euler model of discrete robots, an algorithm is proposed that is capable of computing the internal control torques (and/or forces), as well as the rigid net motions of the robot. In general, this algorithm requires a model of the external forces (responsible for the self-propulsion), but we will see how such a model can be replaced by a kinematic model of a combination of contacts that are related to terrestrial locomotion. Finally, in this case, which we name "kinematic locomotion," the algorithm is illustrated through many examples directly related to elongated body animals, such as snakes, worms, or caterpillars, and their associated biomimetic artifacts.
Cephalopods (i.e., octopuses and squids) are being looked upon as a source of inspiration for the development of unmanned underwater vehicles. One kind of cephalopod-inspired soft-bodied vehicle ...developed by the authors entails a hollow, elastic shell capable of performing a routine of recursive ingestion and expulsion of discrete slugs of fluids which enable the vehicle to propel itself in water. The vehicle performances were found to depend largely on the elastic response of the shell to the actuation cycle, thus motivating the development of a coupled propulsion-elastodynamics model of such vehicles. The model is developed and validated against a set of experimental results performed with the existing cephalopod-inspired prototypes. A metric of the efficiency of the propulsion routine which accounts for the elastic energy contribution during the ingestion/expulsion phases of the actuation is formulated. Demonstration on the use of this model to estimate the efficiency of the propulsion routine for various pulsation frequencies and for different morphologies of the vehicles are provided. This metric of efficiency, employed in association with the present elastodynamics model, provides a useful tool for performing a priori energetic analysis which encompass both the design specifications and the actuation pattern of this new kind of underwater vehicle.
•Whole body cryotherapy can improve health-reported quality of life in fibromyalgia patients.•This study offers a perspective on the impact of Cryotherapy on health.•Patients in the WBC group ...reported significantly improved for health-reported quality of life.
Although fibromyalgia syndrome (SFM) affects 2–4 percent of adults, research has not identified a preferred therapeutic option for patients worldwide yet. Based on recent findings, it can be expected that whole body cryotherapy can improve health-reported quality of life by alleviating the symptoms of musculoskeletal pain and fatigue.
Our aim was to determine whether whole body cryotherapy only can result in improved perceived health and quality of life in fibromyalgia patients.
24 patients with fibromyalgia diagnosis were randomized into 2 groups (n=11 in the whole body cryotherapy group, n=13 in the control group). In the whole body cryotherapy group, 10 sessions of whole body cryotherapy were performed (in addition to usual care) in a standard cryotherapy room over a duration of 8days. Subjects in the control group did not change anything in their everyday activities. Quality of life was assessed just before and one month after treatment.
Compared with the control group, patients in the whole body cryotherapy group reported significantly improved for health-reported quality of life. These effects lasted for at least one month following intervention.
Based on these findings, whole body cryotherapy can be recommended as an effective clinically adjuvant approach in the improvement of health-related quality of life in fibromyalgia patients.
Titanium-based contacts are envisioned for the integration of III-V device contacts on a 300-mm platform, such as photodetectors, semiconductor optical amplifiers (SOAs), and III-V silicon hybrid ...lasers. For the first time, the impact of the thermal budgets of process integration, back-end of line (BEOL), and long-term thermal stress on the electrical characteristics of the Ti/p-In 0.53 Ga 0.47 As and Ti/n-InP contacts has been investigated. Additional physical characterizations have been used to supplement the electrical properties on both systems. Results have indicated that, given a thermal budget between 350 °C and 450 °C during 60 s right after metal deposition, 1) Ti as a contact metal has led to contact resistivity in low <inline-formula> <tex-math notation="LaTeX">10^{-{5}}\,\,\Omega \cdot \text {cm}^{{2}} </tex-math></inline-formula> for p-contacts and in mid <inline-formula> <tex-math notation="LaTeX">10^{-{5}}\,\,\Omega \cdot \text {cm}^{{2}} </tex-math></inline-formula> for n-contacts, which is in accordance with the device requirements; and 2) process integration, BEOL, and long-term thermal stress will not induce any change of the electrical properties. In the scope of III-V silicon hybrid laser contact integration, Ti has hence been evidenced as a suitable candidate for both p- and n-contacts.
This paper reports the first results from a program of work aimed at developing a swimming robot equipped with electric sense. After having presented the principles of a bioinspired electric sensor ...that is now working, we will build the models for electrolocation of objects that are suited to this kind of sensor. The produced models are in a compact analytical form in order to be tractable on the onboard computers of the future robot. These models are tested by comparing them with numerical simulations based on the boundary elements method. The results demonstrate the feasibility of the approach and its compatibility with online objects electrolocation, i.e., another parallel program of ours.
Plant stem cell niches (SCNs) can be maintained in time through asymmetric cell divisions (ACDs) that allow the production of new cell types while constantly renewing the pools of stem cells (SCs). ...ACDs in plants require the asymmetric distribution of molecular components inside the cells as well as external asymmetric positional information. These two types of asymmetric information are controlled by inter- and intracellular signalling events. Phosphorylation of proteins is a major intermediate step in these signalling events, serving either as an activator or repressor of signalling, via fast auto- and trans-phosphorylation mechanisms. Whereas protein kinases, which phosphorylate proteins on serine, threonine or tyrosine residues, have been thoroughly studied, less attention has been given to protein phosphatases, which de-phosphorylate their protein targets on these same residues. Phosphatases modulate the activity of signalling pathways by balancing the action of kinases, and are therefore critical in the regulation of ACDs in plants. In this review, we first present the different types of ACDs that operate during Arabidopsis embryonic and post-embryonic development and participate in the construction and maintenance of its root and shoot SCNs; we then give a brief description of the main protein phosphatases so far described in the Arabidopsis genome; and finally discuss their functions toward the regulation of the ACDs introduced in the first part of the paper.
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