Search results for "Magnitude"
showing 10 items of 501 documents
Chapter 7 HITRAP: A Facility at GSI for Highly Charged Ions
2008
Abstract An overview and status report of the new trapping facility for highly charged ions at the Gesellschaft fur Schwerionenforschung is presented. The construction of this facility started in 2005 and is expected to be completed in 2008. Once operational, highly charged ions will be loaded from the experimental storage ring ESR into the HITRAP facility, where they are decelerated and cooled. The kinetic energy of the initially fast ions is reduced by more than fourteen orders of magnitude and their thermal energy is cooled to cryogenic temperatures. The cold ions are then delivered to a broad range of atomic physics experiments.
HIERARCHICAL MELTING OF ONE-DIMENSIONAL INCOMMENSURATE STRUCTURES
2016
We study the low—temperature properties of quasi one—dimensional, incommensurate structures which are described by a Frenkel—Kontorova—like model. A new type of renormalization method will be presented, which is determined by the continued fraction expansion of the incommensurability ratio ζ. (This method yields a hierarchy of renormalized Hamiltonians ϰ(n,p) describing the thermal behavior for temperatures T = O(T(n,p)), where T(n,p) follows from the continued fraction expansion of ζ. By means of this method the low—temperature specific heat c(T) and the static structure factor S(q) are calculated for fixed ζ. c(T) possesses a hierarchy of Schottky anomalies related to the rational approxi…
Effects of hydrological events on morphological evolution of a fluvial system
2018
Abstract This study quantifies morphological evolution of the Dez River, Iran, from 1955 to 2016. The approach uses a sequence of Landsat images, aerial photos, and topographic maps. In addition, the hydrological data including average daily discharge and yearly maximum discharge at the Dezful hydrological station for the period (1955–2016) were used. The study reach was divided into 48 meander loops from upstream to downstream. Active channel width (w) was determined at 10 m intervals and changes assessed along the study reach of the Dez River. Morphological indices including sinuosity index; straight meander length; centerline flow length; erosion area; erodible length channel migration; …
The relaxation dynamics of a simple glass former confined in a pore
2000
We use molecular dynamics computer simulations to investigate the relaxation dynamics of a binary Lennard-Jones liquid confined in a narrow pore. We find that the average dynamics is strongly influenced by the confinement in that time correlation functions are much more stretched than in the bulk. By investigating the dynamics of the particles as a function of their distance from the wall, we can show that this stretching is due to a strong dependence of the relaxation time on this distance, i.e. that the dynamics is spatially very heterogeneous. In particular we find that the typical relaxation time of the particles close to the wall is orders of magnitude larger than the one of particles …
Modelling sediment delivery using connectivity components at the experimental SPA2 basin, Sicily (Italy)
2018
Sediment delivery ratio can be used as a measure of sediment connectivity and it can be linked to the structural connectivity (morphological unit, slope length, slope steepness, travel time) of a basin and to the functional connectivity (rainfall-runoff processes at morphological unit scale). In this paper the sediment connectivity approach was applied at basin scale both using Sediment Delivery Distributed (SEDD) model, which takes into account the hillslope sediment transport, and sediment yield measurements carried out at SPA2 experimental basin (Sicily, Italy). The expression of the sediment delivery ratio SDRi of a morphological unit was modified for highlighting two components corresp…
Comparative study of techniques for large-scale feature selection* *This work was suported by a SERC grant GR/E 97549. The first author was also supp…
1994
The combinatorial search problem arising in feature selection in high dimensional spaces is considered. Recently developed techniques based on the classical sequential methods and the (l, r) search called Floating search algorithms are compared against the Genetic approach to feature subset search. Both approaches have been designed with the view to give a good compromise between efficiency and effectiveness for large problems. The purpose of this paper is to investigate the applicability of these techniques to high dimensional problems of feature selection. The aim is to establish whether the properties inferred for these techniques from medium scale experiments involving up to a few tens …
Microstructural modifications resulting from the dehydration of gypsum
2001
Various faces of dehydrated gypsum-cleaved blocks and single crystals have been investigated using optical microscopy, SEM, and TEM. The orientation of the cracks with respect to the initial gypsum structure and the Miller indices of all possible crack planes have been determined. These crack planes have been found to be few and to correspond to planes of high atomic density in the initial and final structures, therefore characterised by a low surface tension. These observations allow us to propose cracking criteria based on general concepts of crystal growth. The cracks' dimensions measured on different faces of the pseudomorph are distributed over several orders of magnitude and seems to …
Solid sediment transport in turbulent channel flow over irregular rough boundaries
2017
Abstract The presence of a loading of dispersed particles in a turbulent flow affects the dynamics of the carrier flow field which, in turn, drives grains movement. The focus of the paper is on the analysis of the coupling effects between near-bed turbulence structures and the dynamics of dispersed suspended solid particles in wall-bounded turbulent multiphase flows. We consider turbulent horizontal channel flows bounded by rough boundaries. The friction Reynolds number of the unladen flow is R e τ = 180 and the dispersed phase spans one order of magnitude of particle diameter. To analyze sedimentation and suspended phase transport, we adopt concepts and modeling ideas derived from the Eule…
Crustal Structure of the Seismogenic Volume of the 2010–2014 Pollino (Italy) Seismic Sequence From 3D P- and S-Wave Tomographic Images
2021
A tomographic analysis of Mt. Pollino area (Italy) has been performed using earthquakes recorded in the area during an intense seismic sequence that occurred between 2010 and 2014. 870 local earthquakes with magnitude ranging from 1.8 to 5.0 were selected considering the number of recording stations, the signal quality, and the hypocenter distribution. P- and S-wave arrival times were manually picked and used to compute 3D velocity models through tomographic seismic inversion. The resulting 3D distributions of VP and VS are characterized by high resolution in the central part of the investigated area and from surface to about 10 km below sea level. The aim of the work is to obtain high-qual…
New Results from the NUMEN Project
2018
International audience; NUMEN aims at accessing experimentally driven information on Nuclear Matrix Elements (NME) involved in the half-life of the neutrinoless double beta decay (0νββ), by high-accuracy measurements of the cross sections of Heavy Ion (HI) induced Double Charge Exchange (DCE) reactions. First evidence about the possibility to get quantitative information about NME from experiments is found for the (^18O,^18Ne) and (^20Ne,^20O) reactions. Moreover, to infer the neutrino average masses from the possible measurement of the half-life of 0νββ decay, the knowledge of the NME is a crucial aspect. The key tools for this project are the high resolution Superconducting Cyclotron beam…