Search results for "Simulation"
showing 10 items of 5095 documents
Wave Modulations in the Nonlinear Biinductance Transmission Line
2001
Adding dissipative elements to a discrete biinductance transmission line which admits both low frequency (LF) and high frequency (HF) modes, dynamics of a weakly nonlinear modulated wave is investi...
IMEX Finite Volume Methods for Cloud Simulation
2017
We present new implicit-explicit (IMEX) finite volume schemes for numerical simulation of cloud dynamics. We use weakly compressible equations to describe fluid dynamics and a system of advection-diffusion-reaction equations to model cloud dynamics. In order to efficiently resolve slow dynamics we split the whole nonlinear system in a stiff linear part governing the acoustic and gravitational waves as well as diffusive effects and a non-stiff nonlinear part that models nonlinear advection effects. We use a stiffly accurate second order IMEX scheme for time discretization to approximate the stiff linear operator implicitly and the non-stiff nonlinear operator explicitly. Fast microscale clou…
Commissioning the ATLAS silicon microstrip tracker
2009
Abstract The completed SemiConductor Tracker (SCT) has been installed inside ATLAS. Quick tests were performed last year to verify the connectivity of the electrical and optical services. Problems observed with the heaters for the evaporative cooling system have been resolved. This has enabled extended operation of the full detector under realistic conditions. Calibration data has been taken and analyzed to determine the noise performance of the system. In addition, extensive commissioning with cosmic ray events has started. The cosmic muon data has been used to align the detector, to check the timing of the front-end electronics as well as to measure the hit efficiency of modules. The curr…
Magnetized boxes for housing polarized spins in homogeneous fields
2010
Abstract We present novel types of permanently magnetized as well as current powered boxes built from soft-ferromagnetic materials. They provide shielded magnetic fields which are homogeneous within a large fraction of the enclosed volume, thus minimizing size, weight, and costs. For the permanently magnetized solutions, homogenization is achieved either by an optimized distribution of the permanent field sources or by jacketing the field with a soft-ferromagnetic cylindrical shell which is magnetized in parallel to the enclosed field. The latter principle may be applied up to fields of about 0.1 T. With fields of about 1 mT, such boxes are being used for shipping spin-polarized 3 He worldw…
Results of the 1999 H8 beam tests of ATLAS-SCT prototypes
2001
Abstract During the August–September 1999 test beam in H8 at CERN three half-modules, equipped with different types of fast binary Front End electronics, have been tested. The results indicate that all three SCT electronics candidates satisfy ATLAS efficiency and noise occupancy requirements. In addition, a study on the effect of detector bias voltage on efficiency (ballistic deficit) is reported.
Relative importance of second-order terms in relativistic dissipative fluid dynamics
2013
In Denicol et al., Phys. Rev. D 85, 114047 (2012), the equations of motion of relativistic dissipative fluid dynamics were derived from the relativistic Boltzmann equation. These equations contain a multitude of terms of second order in Knudsen number, in inverse Reynolds number, or their product. Terms of second order in Knudsen number give rise to non-hyperbolic (and thus acausal) behavior and must be neglected in (numerical) solutions of relativistic dissipative fluid dynamics. The coefficients of the terms which are of the order of the product of Knudsen and inverse Reynolds numbers have been explicitly computed in the above reference, in the limit of a massless Boltzmann gas. Terms of …
Glow curve analysis of TLD-100H irradiated with radiation of different LET: Comparison between two theoretical method
2006
In the present paper we show the result of study on the thermoluminescent signal of LiF:Mg,Cu,P (TLD-100H) after irradiation with beams of different LET (photons, electrons and protons). Through the analysis of the glow curve it is possible to obtain information on the LET of the radiation beam. To perform this analysis we have deconvoluted the glow curves adopting general order kinetic equation for the description of the peak shape. In addition a numerical simulation has been performed to find a connection among the physical parameters of the model (OTOR) and the parameters of the empirical expression used in the analysis of the experimental data (GOK). The methodology indicate that the ki…
Electrical analogous in viscoelasticity
2014
In this paper, electrical analogous models of fractional hereditary materials are introduced. Based on recent works by the authors, mechanical models of materials viscoelasticity behavior are firstly approached by using fractional mathematical operators. Viscoelastic models have elastic and viscous components which are obtained by combining springs and dashpots. Various arrangements of these elements can be used, and all of these viscoelastic models can be equivalently modeled as electrical circuits, where the spring and dashpot are analogous to the capacitance and resistance, respectively. The proposed models are validated by using modal analysis. Moreover, a comparison with numerical expe…
Fractional-order theory of heat transport in rigid bodies
2014
Abstract The non-local model of heat transfer, used to describe the deviations of the temperature field from the well-known prediction of Fourier/Cattaneo models experienced in complex media, is framed in the context of fractional-order calculus. It has been assumed (Borino et al., 2011 [53] , Mongiovi and Zingales, 2013 [54] ) that thermal energy transport is due to two phenomena: ( i ) A short-range heat flux ruled by a local transport equation; ( ii ) A long-range thermal energy transfer proportional to a distance-decaying function, to the relative temperature and to the product of the interacting masses. The distance-decaying function is assumed in the functional class of the power-law …
Modulational stability brought by cubic–quartic interactions of the nearest-neighbor in FK model subjected in a parametrized on-site potential
2022
Abstract This work extends to higher-order interactions the results of Ref. Nguetcho (2021), in which we discussed only on modulational instability in one-dimensional chain made of atoms, harmonically coupled to their nearest neighbors and subjected to an external on-site potential. Here we investigate the competition between cubic-quartic nonlinearities interactions of the nearest-neighbor and substrate’s deformability, and mainly discuss its impact on the modulational instability of the system. This makes it possible to adapt the theoretical model to a real physical system such as atomic chains or DNA lattices. The governing equation, derived from the modified Frenkel-Kontorova model, is …