Effect of long-range Coulomb interaction on shot-noise suppression in ballistic transport

We present a microscopic analysis of shot-noise suppression due to long-range Coulomb interaction in semiconductor devices under ballistic transport conditions. An ensemble Monte Carlo simulator self-consistently coupled with a Poisson solver is used for the calculations. A wide range of injection-rate densities leading to different degrees of suppression is investigated. A sharp tendency of noise suppression at increasing injection densities is found to scale with a dimensionless Debye length related to the importance of space-charge effects in the structure.

An octree isosurface codification based on discrete planes

Describes a method to code a decimated model of an isosurface on an octree representation while maintaining volume data if it is needed. The proposed technique is based on grouping the marching cubes (MC) patterns into five configurations according the topology and the number of planes of the surface that are contained in a cell. Moreover, the discrete number of planes on which the surface lays is fixed. Starting from a complete volume octree, with the isosurface codified at terminal nodes according to the new configuration, a bottom-up strategy is taken for merging cells. Such a strategy allows one to implicitly represent co-planar faces in the upper octree levels without introducing any error. At the end of this merging process, when it is required, a reconstruction strategy is applied to generate the surface contained in the octree intersected leaves. Some examples with medical data demonstrate that a reduction of up to 50% in the number of polygons can be achieved

Energy intensity in road freight transport of heavy goods vehicles in Spain

This paper examines the factors that have influenced the energy intensity of the Spanish road freight transport of heavy goods vehicles over the period 1996–2012. This article aims to contribute to a better understanding of the factors behind the energy intensity change of road freight and also to inform the design of measures to improve energy efficiency in road freight transport. The paper uses both annual single-period and chained multi-period multiplicative LMDI-II decomposition analysis. The results suggest that the decrease in the energy intensity of Spanish road freight in the period is explained by the change in the real energy intensity index (lower energy consumption per tonne-kilometre transported), which is partially offset by the behaviour of the structural index (greater share in freight transport of those commodities the transportation of which is more energy intensive). The change in energy intensity is analysed in more depth by quantifying the contribution of each commodity through the attribution of changes in Divisia indices.

Càlcul estructural per a l’estabilització de la plataforma a reurbanitzar del c/ Sant Francesc d’Assís al barri de les Planes. Sant Cugat del Vallès

Estudi estructural per reurbanitzar el carrer Sant Francesc d’Assís de Les Planes, que s’assenta en una configuració de mitja vessant sobre un conjunt triple d’estrats de terreny. Al llarg dels anys s’han produït esllavissaments que han afectat l’àmbit de reblert i algun fins i tot activant els sols quaternaris. La solució proposada és basa en una pantalla curta encastada al substrat rocós, situat al voltant dels 5m. de profunditat, i superiorment lligada per una nova llosa solidària amb l’existent (fregament), però fonamentalment vinculada a un petit mort costat muntanya que, per empenta passiva del terreny, acaba conformant el suport fix de l’esquema estructural en “T”.