Search results for "Computer Science::Other"
showing 10 items of 50 documents
Lead evaporation instabilities and failure mechanisms of the micro oven at the GTS-LHC ECR ion source at CERN
2020
The GTS-LHC ECR ion source (named after the Grenoble Test Source and the Large Hadron Collider) at CERN provides heavy ion beams for the chain of accelerators from Linac3 up to the LHC for high energy collision experiments and to the Super Proton Synchrotron for fixed target experiments. During the standard operation, the oven technique is used to evaporate lead into the source plasma to produce multiple charged lead ion beams. Intensity and stability are key parameters for the beam, and the operational experience is that some of the source instabilities can be linked to the oven performance. Over long operation periods of several weeks, the evaporation is not stable which makes the tuning …
Internal model-based feedback control design for inversion-free feedforward rate-dependent hysteresis compensation of piezoelectric cantilever actuat…
2018
Abstract This study proposes a new rate-dependent feedforward compensator for compensation of hysteresis nonlinearities in smart materials-based actuators without considering the analytical inverse model. The proposed rate-dependent compensator is constructed with the inverse multiplicative structure of the rate-dependent Prandtl–Ishlinskii (RDPI) model. The study also presents an investigation for the compensation error when the proposed compensator is applied in an open-loop feedforward manner. Then, an internal model-based feedback control design is applied with the proposed feedforward compensator to a piezoelectric cantilever actuator. The experimental results illustrate that the propo…
Probing mechanical quantum coherence with an ultracold-atom meter
2011
We propose a scheme to probe quantum coherence in the state of a nano-cantilever based on its magnetic coupling (mediated by a magnetic tip) with a spinor Bose Einstein condensate (BEC). By mapping the BEC into a rotor, its coupling with the cantilever results in a gyroscopic motion whose properties depend on the state of the cantilever: the dynamics of one of the components of the rotor angular momentum turns out to be strictly related to the presence of quantum coherence in the state of the cantilever. We also suggest a detection scheme relying on Faraday rotation, which produces only a very small back-action on the BEC and it is thus suitable for a continuous detection of the cantilever'…
Toward Parametrization of Precipitating Shallow Cumulus Cloud Organization via Moisture Variance
2021
The influence of the initial vertical moisture profile on precipitating shallow cumulus cloud organization in terms of the column‐averaged moisture variance is investigated using large‐eddy simulations. Five idealized simulations based on the Rain in Cumulus over the Ocean field experiment with different initial moisture profiles are investigated. All cases simulate precipitating shallow cumulus convection in a marine sub‐tropical region under large‐scale subsidence. The results show that the moisture variance is mainly generated through the interaction of the moisture flux and the moisture gradient in the gradient production term at the top of the boundary layer. The development is charact…
Ab initio modelling of the effects of varying Zr (Ti) concentrations on the atomic and electronic properties of stoichiometric PZT solid solutions
2017
Abstract Lead zirconate titanate Pb(ZrxTi1−x)O3 solid solution is considered as one of the most advanced ferroelectric and piezoelectric materials. Consequent variation of Zr (Ti) concentrations significantly affects the atomic and electronic properties of PZT structures. To perform ab initio modelling of different morphologies for lead zirconate titanate, we are using approach of hybrid density functional B3PW as implemented in CRYSTAL14 computer code. In this study, we are performing large-scale calculations of such PZT parameters as optimized lattice constants, atomic charges and bond populations, as well as band structure (e.g., band gap) and density of states.
Monte Carlo Application in Brachytherapy Dosimetry
2009
This paper devoted to Monte-Carlo Applications in BT Dosimetry is organized in four parts: 1. Motivation of the use of Monte Carlo in brachytherapy 2. The use of Monte Carlo to obtain dose distribution around brachytherapy sources 3. Experimental dosimetry versus Monte Carlo 4. Others Monte Carlo applications in brachytherapy
Comment on ``Friedel phases and phases of transmission amplitudes in quantum scattering systems" by T. Taniguchi and M. Buettiker
1999
We take a modified boundary condition at the dead end of a stub to simulate transmission zeroes being replaced by minima and then the discontinuous phase slip (or decrease) at the transmission zeroes are replaced by a continuous but rapid phase slip. The modified boundary condition can be continuously tuned to give the results of the stub with hard wall boundary condition at the dead end of stub. Even when the phase slip is continuous one can obtain information about the density of states in the stub region from the scattering phases.
Mobility, interdiffusion, and tracer diffusion in lattice-gas models of two-component alloys
1989
The transport properties of lattice-gas models of alloys with two particle species are studied. The numbers of the particles and vacancies are conserved, and the two particle species have different exchange rates with the vacancies. The mobility and interdiffusion is described by the linear Onsager theory of transport. The Onsager coefficients are estimated from numerical simulations of the mobilities. A recently proposed relation between the Onsager coefficients of the random-alloy model is verified. The interdiffusion of the two species is directly monitored in the simulations; it is well described by the estimated Onsager coefficients. The results on interdiffusion are compared with simu…
Relation of Interdiffusion and Self-Diffusion in Polymer Mixtures
1986
From different assumptions one obtains linear relationships either between the interdiffusion coefficient and the self-diffusion coefficients or between the inverse interdiffusion coefficient and the inverse self-diffusion coefficients. The nature of these assumptions and possible experiments for discriminating between them are discussed.
General aspects regarding the kinematic and dynamic analysis of the fabric take up/cloth roller
2017
The aim of this paper is to presents different aspects regarding the kinematic and dynamic behaviour of the fabric winding at the weaving loom. In this paper shall be presented the kinematic diagram for operating the cloth roll on the weaving machine, making the study of kinematic and dynamic cloth behaviour, setting up the expression of fabric tension. Finally, where drawn the charts of the variation of the fabric load depending by kinematic and constructive parameters.