Search results for "scale [mass]"
showing 10 items of 997 documents
Squeezing of Quantum Noise of Motion in a Micromechanical Resonator
2015
A pair of conjugate observables, such as the quadrature amplitudes of harmonic motion, have fundamental fluctuations which are bound by the Heisenberg uncertainty relation. However, in a squeezed quantum state, fluctuations of a quantity can be reduced below the standard quantum limit, at the cost of increased fluctuations of the conjugate variable. Here we prepare a nearly macroscopic moving body, realized as a micromechanical resonator, in a squeezed quantum state. We obtain squeezing of one quadrature amplitude $1.1 \pm 0.4$ dB below the standard quantum limit, thus achieving a long-standing goal of obtaining motional squeezing in a macroscopic object.
Enhancing Optomechanical Coupling via the Josephson Effect
2013
Cavity optomechanics is showing promise for studying quantum mechanics in large systems. However, smallness of the radiation-pressure coupling is a serious hindrance. Here we show how the charge tuning of the Josephson inductance in a single-Cooper-pair transistor (SCPT) can be exploited to arrange a strong radiation pressure -type coupling $g_0$ between mechanical and microwave resonators. In a certain limit of parameters, such a coupling can also be seen as a qubit-mediated coupling of two resonators. We show that this scheme allows reaching extremely high $g_0$. Contrary to the recent proposals for exploiting the non-linearity of a large radiation pressure coupling, the main non-linearit…
Effetti distorsivi dei Trattati Euromediterranei di associazione e mancanza di clausole antiabuso: il caso algerino.
2014
La mancanza di clausole antiabuso specifiche nel Trattato di associazione euromediterraneo stipulato tra UE ed Algeria consente un uso indebito dello stesso al fine di erodere la base imponibile ai fini delle imposte dirette nell'ambito di una pianificazione fiscale aggressiva
Comparison of the accumulation of fibre breaks occurring in a unidirectional carbon/epoxy composite identified in a multi-scale micro-mechanical mode…
2010
National audience; A model to predict fibre break accumulation that takes into account all physical phenomena at the origin of the fibre break (i.e. the random nature, stress transfer due to breaks, fibre debonding and viscosity of the matrix) shows clearly that the failure of a unidirectional composite structure results in the formation of random fibre breaks which at higher loads coalesce into clusters of broken fibres. The object of the study is to experimentally confirm this scenario. Many techniques exist to detect the failure of carbon fibre composites, however none of them offer a resolution that allows this goal to be achieved in a non-destructive manner and in three dimensions. Hig…
Effect of the Time Dependent Loading of Type IV Cylinders using a Multiscale Model
2019
International audience; The current requirements for composite cylinders are still based on an arbitrary approach derived from the behaviour of metal structures, that the designed burst pressure should be at least 2.5 times the maximum in-service pressure [1]. This could lead to an over-designed composite cylinder for which the weight saving would be less than optimum. Moreover, predicting the lifetime of composite cylinders is a challenging task due to their anisotropic characteristics. A federal research institute in Germany (BAM) has proposed a minimum load-cycle requirement that mitigates this issue by using a Monte-Carlo analysis of the burst test results [2-3]. To enrich this study, m…
Analyse multiéchelle d'un composite textile = Multiscale analysis of a textile composite
2009
National audience; On propose dans cette étude de comprendre le comportement mécanique d'un composite textile. Pour ce faire, l'étude se scinde en deux parties distinctes. Dans cet article, nous présentons la modélisation multiéchelle qui fait suite à une étude expérimentale. Son objectif est double : comprendre la nature du comportement macroscopique observé et expliquer l'origine des endommagements susceptibles d'apparaître. L'étude expérimentale du matériau fait l'objet d'un premier article.
Non-thermal pressure support in X-COP galaxy clusters
2018
Galaxy clusters are the endpoints of structure formation and are continuously growing through the merging and accretion of smaller structures. Numerical simulations predict that a fraction of their energy content is not yet thermalized, mainly in the form of kinetic motions (turbulence, bulk motions). Measuring the level of non-thermal pressure support is necessary to understand the processes leading to the virialization of the gas within the potential well of the main halo and to calibrate the biases in hydrostatic mass estimates. We present high-quality measurements of hydrostatic masses and intracluster gas fraction out to the virial radius for a sample of 12 nearby clusters with availab…
Mesoscale eddies, surface circulation and the scale of habitat selection by immature loggerhead sea turtles
2007
17 pages, 8 figures, 6 tables
An Improved Hierarchical ACA Technique for Sound Absorbent Materials
2011
This paper presents an improved adaptive cross approximation (ACA) approach developed in conjunction with the Hierarchical format matrix and the GMRES solver. A novel scheme to generate the cluster tree (based upon preliminary considerations of the prescribed boundary conditions) and an improved ACA algorithm (approximating the system matrix for mixed Robin conditions) are described. The asymptotic smoothness property of a kernel generated by a linear combination of two asymptotic smooth kernels is demonstrated. Numerical results show the new approach to be up to 50% faster than the conventional ACA approach.
A hierarchical-ACA technique for large-scale acoustic simulations: complex geometries with sound adsorbent materials
2012
In this paper a boundary element approach for acoustic simulations based on the hierarchical-matrix format coupled with the adaptive cross approximation (ACA) algorithm and a hierarchical GMRES solver is presented. The cluster tree is generated using preliminary considerations of the prescribed boundary conditions. An improved ACA algorithm, applied, separately, to Neumann, Dirichlet and mixed Robin conditions, is described. Numerical results are presented to show the new approach to be up to 50% faster than conventional ACA approach.