Search results for " MODELLI"
showing 10 items of 1472 documents
Study of the material of the ATLAS inner detector for Run 2 of the LHC
2017
The ATLAS inner detector comprises three different sub-detectors: the pixel detector, the silicon strip tracker, and the transition-radiation drift-tube tracker. The Insertable B-Layer, a new innermost pixel layer, was installed during the shutdown period in 2014, together with modifications to the layout of the cables and support structures of the existing pixel detector. The material in the inner detector is studied with several methods, using a low-luminosity root s = 13 TeV pp collision sample corresponding to around 2.0 nb(-1) collected in 2015 with the ATLAS experiment at the LHC. In this paper, the material within the innermost barrel region is studied using reconstructed hadronic in…
From local measures to regional impacts: Modelling changes in nutrient loads to the Baltic Sea
2021
Study Region: Our study region is the Baltic Sea Drainage Basin (BSDB), which covers an area of 1.8 Mio km2 distributed over 14 countries in northern Europe. Study Focus: We use a large-scale hydrological and nutrient transport model (E-HYPE) to model basin-wide impacts of measure scenarios on the Baltic Sea, where eutrophication is a critical issue for the marine ecosystem. We constructed measure scenarios based on stakeholder acceptance, established in workshops in different regions around the Baltic. These measures include local stream reach to catchment scale measures aiming to reduce nutrient transport into the stream network (buffer strips, stormwater ponds) and measures aiming to red…
Stochastic seismic analysis of hydrodynamic pressure in dam reservoir systems
2002
Hydrodynamic seismic-induced pressure requires careful consideration in the aseismic design of dams. Effects induced by earthquake excitation may cause many-fold increments of hydrostatic pressure. In this study earthquake excitation has been modelled by means of random process theory obtaining the response statistics of a dam-reservoir dynamical system. The analysis has been conducted assuming a rigid retaining wall of the reservoir and dissipative fluid. Copyright © 2002 John Wiley & Sons, Ltd.
A layer correlation technique for pion energy calibration at the 2004 ATLAS Combined Beam Test
2010
A new method for calibrating the hadron response of a segmented calorimeter is developed and successfully applied to beam test data. It is based on a principal component analysis of energy deposits in the calorimeter layers, exploiting longitudinal shower development information to improve the measured energy resolution. Corrections for invisible hadronic energy and energy lost in dead material in front of and between the calorimeters of the ATLAS experiment were calculated with simulated Geant4 Monte Carlo events and used to reconstruct the energy of pions impinging on the calorimeters during the 2004 Barrel Combined Beam Test at the CERN H8 area. For pion beams with energies between 20GeV…
There's more to volatility than volume
2006
It is widely believed that fluctuations in transaction volume, as reflected in the number of transactions and to a lesser extent their size, are the main cause of clustered volatility. Under this view bursts of rapid or slow price diffusion reflect bursts of frequent or less frequent trading, which cause both clustered volatility and heavy tails in price returns. We investigate this hypothesis using tick by tick data from the New York and London Stock Exchanges and show that only a small fraction of volatility fluctuations are explained in this manner. Clustered volatility is still very strong even if price changes are recorded on intervals in which the total transaction volume or number of…
Harmonic generation from nanorings driven by a two-color laser field
2014
We study the high harmonic generation and the polarization of the harmonics emitted by a nanoring driven by two laser fields of angular frequency ?1 and ?2, with ?2?=?2?1, and ?1 resonant between the ground and the first excited state. We show that by varying parameters, such as laser intensity, photon energy and the delay between the two laser pulses, we can control the number of harmonics and the polarization of the radiation. In particular we show that with this choice of two-laser photon frequency rate we obtain more harmonics with respect to other configurations. We also calculated the average absorbed energy and the average angular momentum acquired by the electron as a function of th…
An optimized Bell test in a dynamical system
2010
The best realization of a Bell test depends on parameters linked to experimental settings. We report, for a class of two-qubit states, some optimized parameters that are useful to perform an optimized Bell test in a dynamical context. The time evolution of these optimized parameters, that present finite jumps, is investigated for two qubits in separated cavities.
Optimal persistent currents for interacting bosons on a ring with a gauge field
2013
We study persistent currents for interacting one-dimensional bosons on a tight ring trap, subjected to a rotating barrier potential, which induces an artificial U(1) gauge field. We show that, at intermediate interactions, the persistent current response is maximal, due to a subtle interplay of effects due to the barrier, the interaction and quantum fluctuations. These results are relevant for ongoing experiments with ultracold atomic gases on mesoscopic rings.
Stochastic Models of Higher Order Dielectric Responses
2018
The nonlinear response for systems exhibiting Markovian stochastic dynamics is calculated using time-dependent perturbation theory for the Green’s function, the conditional probability to find the system in a given configuration at a certain time given it was in another configuration at an earlier time. In general, the Green’s function obeys a so-called master-equation for the balance of the gain and loss of probability in the various configurations of the system. Using various models for the reorientational motion of molecules it is found that the scaled modulus of the third-order response, \(X_3\), shows a hump-like behavior for random rotational motion in some cases and it exhibits “triv…
The A + B → 0 reaction on a disordered lattice
1996
Abstract In this paper a stochastic model for the A + B → 0 reaction with creation of particles on a disordered surface is studied for d = 2 and d = 3 spatial dimensions. Densities and correlations of the particles are examined in detail. We find that the stationary state which exists for d = 3 in case of an ordered lattice vanishes in the case of a disordered lattice. A stationary state for d = 2 never exists.