The non dissipative damping of the Rabi oscillations as a "which-path" information

Rabi oscillations may be viewed as an interference phenomenon due to a coherent superposition of different quantum paths, like in the Young's two-slit experiment. The inclusion of the atomic external variables causes a non dissipative damping of the Rabi oscillations. More generally, the atomic translational dynamics induces damping in the correlation functions which describe non classical behaviors of the field and internal atomic variables, leading to the separability of these two subsystems. We discuss on the possibility of interpreting this intrinsic decoherence as a "which-way" information effect and we apply to this case a quantitative analysis of the complementarity relation as introduced by Englert [Phys. Rev. Lett. \textbf{77}, 2154 (1996)].Comment: 5 pages, 2 figure

Passive flow control study in a convoluted intake using Stereo Particle Image Velocimetry

The ability of vortex generators (VG) to reduce the unsteady distortion at the exit plane of an S-duct (AIP) is investigated. The 3 components of the velocity at the AIP were measured using a Stereo Particle Velocimetry system with high spatial resolution. This enabled an assessment of the synchronous swirl distortion at the duct exit. A total of nine VG cases have been investigated with a systematic variation of key design variables. Overall the VGs change the duct secondary flows and separation and are able to substantially restructure the flow field at the AIP. The pressure distortion could be reduced up to 50% and a reduction in pressure loss of 30% was achieved for the mean flow field. The VGs have a substantial influence on the unsteadiness of the flow field with a reduction in peak swirl unsteadiness of 61% and an overall reduction of unsteady swirl distortion of 67%. They also suppress the primary unsteady flow switching mechanism of the datum configuration which is associated with the oscillation of bulk and twin swirl regimes. Consequently, extreme events which leads to high swirl intensity are suppressed which lower by 45% the maximum swirl intensity for the VG cases

Controllability indices for structured systems

AbstractA new methodology is proposed for the characterization of the controllability indices of linear multivariable systems. Related to the state space representation, a new symbolism dealing only with numbers associated with the position of nonnull terms of matrices is proposed. This symbolism, associated with the graphical digraph representation model, allows one to highlight, from a structural point of view, a list of dimensions of controllable subspaces corresponding one to one with the list of controllability indices

Dynamic flow distortion investigation in an S-duct using DDES and SPIV data

The dynamic flow distortion generated within convoluted aero-engine intakes can affect the performance and operability of the engine. There is a need for a better understanding of the main flow mechanisms which promote flow distortion at the exit of S-shaped intakes. This paper presents a detailed analysis of the main coherent structures in an S-duct flow field based on a Delayed Detached Eddy Simulation (DDES). The DDES capability to capture the characteristics of the highly unsteady flow field is demonstrated against high resolution, synchronous Stereoscopic Particle Image Velocimetry (SPIV) measurements at the Aerodynamic Interface Plane (AIP). The flow field mechanisms responsible for the main AIP perturbations are identified. Clockwise and counter-clockwise stream-wise vortices are alternately generated around the separation region at a frequency of St=0.53, which promotes the swirl switching at the AIP. Spanwise vortices are also shed from the separation region at a frequency of St=1.06, and convect downstream along the separated centreline shear layer. This results in a vertical modulation of the main loss region and a fluctuation of the velocity gradient between the high and low velocity flow at the AIP

Pre-equilibrium dileptons look thermal

The dilepton mass distribution from pre-equilibrium matter in ultrarelativistic nuclear collisions is indistinguishable from a thermally produced distribution.Comment: CERN-TH.6813/93, 3 pages (latex) plus 1 figure (uuencoded postscript file

Storage Device Sizing for a Hybrid Railway Traction System by Means of Bicausal Bond Graphs

In this paper, the application of bicausal bond graphs for system design in electrical engineering is emphasized. In particular, it is shown how this approach is very useful for model inversion and parameter dimensioning. To illustrate these issues, a hybrid railway traction device is considered as a case study. The synthesis of a storage device (a supercapacitor) included in this system is then discussed

Bone Quality Changes In 3 Cases Of Hypophosphatasia: A Ftiri Study

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Unified constitutive equations to describe elastoplastic and damage behavior of an X100 linepipe steel

International audienceThe deformation and fracture of the high strength steel which is used to fabricate grade X100 steel pipe were investigated at room temperature, on plate and pipe. Anisotropic behaviour was characterized by using tensile tests conducted along different directions. The fracture toughness of plate and pipe materials are compared using compact tension (CT) and Charpy V-notched tests. In both cases, these materials give rise to good fracture properties. The aim of the present study is to establish unified constitutive equations able to describe the elastoplastic and damage behavior of one X100 linepipe steel. The model is then used to simulate three point bending and compact tension tests