In situ GISAXS study of the growth of Pd on MgO(001)

The morphology of growing Pd nano-particles on MgO(001) surfaces have been investigated in situ, during growth, by grazing incidence small angle x-ray scattering, for different substrate temperatures. The 2D patterns obtained are quantitatively analyzed, and the average morphological parameters (shape, size) deduced. Above 650 K, the aggregates adopt their equilibrium shape of truncated octahedron, and the interfacial energy is deduced.Comment: 10 pages, 1 Table, 2 Figure

The growth of a Super Stable Heap : an experimental and numerical study

We report experimental and numerical results on the growth of a super stable heap (SSH). Such a regime appears for flows in a thin channel and for high flow rate : the flow occurs atop a nearly static heap whose angle is stabilized by the flowing layer at its top and the side wall friction. The growth of the static heap is investigated in this paper. A theoretical analysis inspired by the BRCE formalism predicts the evolution of the growth process, which is confirmed by both experiments and numerical simulations. The model allows us to link the characteristic time of the growth to the exchange rate between the "moving" and "static" grains. We show that this rate is proportional to the height of the flowing layer even for thick flows. The study of upstream traveling waves sheds new light on the BCRE model

Multi-Objective Design Optimization of the Leg Mechanism for a Piping Inspection Robot

This paper addresses the dimensional synthesis of an adaptive mechanism of contact points ie a leg mechanism of a piping inspection robot operating in an irradiated area as a nuclear power plant. This studied mechanism is the leading part of the robot sub-system responsible of the locomotion. Firstly, three architectures are chosen from the literature and their properties are described. Then, a method using a multi-objective optimization is proposed to determine the best architecture and the optimal geometric parameters of a leg taking into account environmental and design constraints. In this context, the objective functions are the minimization of the mechanism size and the maximization of the transmission force factor. Representations of the Pareto front versus the objective functions and the design parameters are given. Finally, the CAD model of several solutions located on the Pareto front are presented and discussed.Comment: Proceedings of the ASME 2014 International Design Engineering Technical Conferences \& Computers and Information in Engineering Conference, Buffalo : United States (2014

Toward a knowledge representation model dedicated to the semantic analysis of the sentence

Ce rapport a été rédigé en octobre 2005 mais n'a été publié en tant que rapport INRIA qu'en juillet 2006Ce travail se situe dans le cadre de l'étude de la sémantique du langage naturel. Il s'agit d'une reformulation précise et automatisable du Lexique Génératif de Pustejovsky. Nous proposons un modèle lexical simultanément descriptif de la structure sémantique interne des mots et applicable de manière automatique à la suite d'une analyse syntaxique classique, par exemple celle des grammaires catégorielles. Notre formalisation des règles et nos algorithmes qui permettent de les appliquer sont illustrés par le traitement de la reconstruction métonymique et des usages ambigus de la préposition “avec”. (Ce rapport a été rédigé en octobre 2005 mais n'a été publié qu'en juillet 2006.

Simulation of morphological plasticity of Acacia tortilis in response to herbivore attacks

International audienceUnderstanding tree architectural plasticity is a major challenge. Functional-structural models can be of great interest to quantify the allocation patterns and their changes according to environment. In this paper, we focus on Acacia tortilis trees in savanna to understand their responses to herbivore attacks both in terms of architecture and allocation pattern. Measurements were carried out in Hwange National Park (Zimbabwe) in 2008. Architectural and biomass data were analysed to quantify the effects of herbivore attacks on plant morphogenesis, and trees were gathered in two groups depending on the intensity of herbivore attacks they suffered. Based on these results, a simple model of herbivore attacks has been implemented and parameters have been estimated in the framework of the GreenLab model and we simulate different realistic behaviours according to the intensity of herbivore attacks

Toward a knowledge representation model dedicated to the semantic analysis of the sentence

Ce rapport a été rédigé en octobre 2005 mais n'a été publié en tant que rapport INRIA qu'en juillet 2006Ce travail se situe dans le cadre de l'étude de la sémantique du langage naturel. Il s'agit d'une reformulation précise et automatisable du Lexique Génératif de Pustejovsky. Nous proposons un modèle lexical simultanément descriptif de la structure sémantique interne des mots et applicable de manière automatique à la suite d'une analyse syntaxique classique, par exemple celle des grammaires catégorielles. Notre formalisation des règles et nos algorithmes qui permettent de les appliquer sont illustrés par le traitement de la reconstruction métonymique et des usages ambigus de la préposition “avec”. (Ce rapport a été rédigé en octobre 2005 mais n'a été publié qu'en juillet 2006.

Substrate arrays of iridium oxide microelectrodes for in vitro neuronal interfacing

The design of novel bidirectional interfaces for in vivo and in vitro nervous systems is an important step towards future functional neuroprosthetics. Small electrodes, structures and devices are necessary to achieve high-resolution and target-selectivity during stimulation and recording of neuronal networks, while significant charge transfer and large signal-to-noise ratio are required for accurate time resolution. In addition, the physical properties of the interface should remain stable across time, especially when chronic in vivo applications or in vitro long-term studies are considered, unless a procedure to actively compensate for degradation is provided. In this short report, we describe the use and fabrication of arrays of 120 planar microelectrodes (MEAs) of sputtered Iridium Oxide (IrOx). The effective surface area of individual microelectrodes is significantly increased using electrochemical activation, a procedure that may also be employed to restore the properties of the electrodes as required. The electrode activation results in a very low interface impedance, especially in the lower frequency domain, which was characterized by impedance spectroscopy. The increase in the roughness of the microelectrodes surface was imaged using digital holographic microscopy and electron microscopy. Aging of the activated electrodes was also investigated, comparing storage in saline with storage in air. Demonstration of concept was achieved by recording multiple single-unit spike activity in acute brain slice preparations of rat neocortex. Data suggests that extracellular recording of action potentials can be achieved with planar IrOx MEAs with good signal-to-noise ratios. © 2009 Gawad, Giugliano, Heuschkel, Wessling, Markram, Schnakenberg, Renaud and Morgan