590 research outputs found
Efficient table-top dual-wavelength beamline for ultrafast transient absorption spectroscopy in the soft X-ray region.
We present a table-top beamline providing a soft X-ray supercontinuum extending up to 370 eV from high-order harmonic generation with sub-13 fs 1300 nm driving pulses and simultaneous production of sub-5 fs pulses centered at 800 nm. Optimization of high harmonic generation in a long and dense gas medium yields a photon flux of ~ 1.4 × 106 photons/s/1% bandwidth at 300 eV. The temporal resolution of X-ray transient absorption experiments with this beamline is measured to be 11 fs for 800 nm excitation. This dual-wavelength approach, combined with high flux and high spectral and temporal resolution soft X-ray absorption spectroscopy, is a new route to the study of ultrafast electronic dynamics in carbon-containing molecules and materials at the carbon K-edge
Evaluating the predicted reliability of mechatronic systems: state of the art
Reliability analysis of mechatronic systems is a recent field and a dynamic
branch of research. It is addressed whenever there is a need for reliable,
available, and safe systems. The studies of reliability must be conducted
earlier during the design phase, in order to reduce costs and the number of
prototypes required in the validation of the system. The process of reliability
is then deployed throughout the full cycle of development. This process is
broken down into three major phases: the predictive reliability, the
experimental reliability and operational reliability. The main objective of
this article is a kind of portrayal of the various studies enabling a
noteworthy mastery of the predictive reliability. The weak points are
highlighted. Presenting an overview of all the quantitative and qualitative
approaches concerned with modelling and evaluating the prediction of
reliability is so important for future reliability studies and for academic
research to come up with new methods and tools. The mechatronic system is a
hybrid system, it is dynamic, reconfigurable, and interactive. The modeling
carried out of reliability prediction must take into account these criteria.
Several methodologies have been developed in this track of research. In this
regard, the aforementioned methodologies will be analytically sketched in this
paper.Comment: 13 page, Mechanical Engineering: An International Journal (MEIJ),
Vol. 3, No. 2, May 201
Prise en compte des interactions multi-domaines lors de l’évaluation de la fiabilité prévisionnelle des systèmes mécatroniques
The mechatronic systems are hybrid, dynamic, interactive and reconfigurable. Therefore their dysfunctional modeling is very difficult. Multi-physical interactions between components have impacts on the degradation or on system failures, leading thus to more uncertainty in reliability evaluation.
The work presented in this paper aims to improve the integration of multi-domain interactions in the reliability assessment of mechatronic systems.
After a presentation of the state of the art of mechatronic systems reliability estimation methods, we propose to represent multi domain interactions by influential factors in the dysfunctional model. We generally use proportional hazard models; in the case of an interaction represented by a temperature stress, Arrhenius model is used
Evidential Networks for Evaluating Predictive Reliability of Mechatronics Systems under Epistemic Uncertainties
In reliability predicting field, the probabilistic approaches are based on data relating to the components which can be precisely known and validated by the return of experience REX, but in the case of complex systems with high-reliability precision such as mechatronic systems, uncertainties are inevitable and must be considered in order to predict with a degree of confidence the evaluated reliability. In this paper, firstly we present a brief review of the non-probabilistic approaches. Thereafter we present our methodology for assessing the reliability of the mechatronic system by taking into account the epistemic uncertainties (uncertainties in the reliability model and uncertainties in the reliability parameters) considered as a dynamic hybrid system and characterized by the existence of multi-domain interaction between its failed components. The key point in this study is to use an Evidential Network “EN” based on belief functions and the dynamic Bayesian network. Finally, an application is developed to illustrate the interest of the proposed methodology
Composition-Dependent Passivation Efficiency at the CdS/CuIn1-xGaxSe2 Interface
International audienc
Dynamic Bayesian Network for Reliability of Mechatronic System with Taking Account the Multi-Domain Interaction
This article presents a methodology for reliability prediction during the design phase of mechatronic system considered as an interactive dynamic system. The difficulty in modeling reliability of a mechatronic system is mainly due to failures related to the interaction between the different domains called Multi-domain interaction. Therefore in this paper, after a presentation of the state of the art of mechatronic systems reliability estimation methods, we propose a original approach by representing multi domain interactions by influential factors in the dysfunctional modeled by Dynamic Bayesian Networks. A case study demonstrates the interest of the proposed approach
Evaluation of the mechatronic systems reliability under parametric uncertainties
The main research intent of this paper is to evaluate the predicted reliability of mechatronic system, with take into account the epistemic uncertainties, The work reported here presents a new methodology based on integrating the petri network with the belief functions, in order to create a belief network, and to show how to propagate the parametric uncertainties in reliability models, Some notions of uncertainty related to the reliability systems are presented, subsequently a brief definition of the belief function and its application in reliability studies are detailed and how we integrate it in petri network. To take into account the interactive aspect of mechatronic systems, we introduce the uncertainties associated to this interaction, by implementing the new method proposed by using belief network. Secondly, we study the propagation of these interaction uncertainties in system reliability. Finally, in regard to applicate the methodology, an industrial example "intelligent actuator" is developed
Inelastic nucleon contributions in nuclear response functions
We estimate the contribution of inelastic nucleon excitations to the
inclusive cross section in the CEBAF kinematic range.
Calculations are based upon parameterizations of the nucleon structure
functions measured at SLAC. Nuclear binding effects are included in a
vector-scalar field theory, and are assumed have a minimal effect on the
nucleon excitation spectrum. We find that for q\lsim 1 GeV the elastic and
inelastic nucleon contributions to the nuclear response functions are
comparable, and can be separated, but with roughly a factor of two uncertainty
in the latter from the extrapolation from data. In contrast, for q\rsim 2 GeV
this uncertainty is greatly reduced but the elastic nucleon contribution is
heavily dominated by the inelastic nucleon background.Comment: 20 pages, 7 figures available from the authors at Department of
Physics and Astronomy, University of Rochester, Rochester NY 1462
Superscaling in inclusive electron-nucleus scattering
We investigate the degree to which the scaling functions derived
from cross sections for inclusive electron-nucleus quasi-elastic scattering
define the same function for different nuclei. In the region where the scaling
variable , we find that this superscaling is experimentally realized
to a high degree.Comment: Corrected previously mislabeled figures and cross references; 9
pages, 4 color figures, using BoxedEPS and REVTeX; email correspondence to
[email protected]
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