Delft University of Technology

About: Delft University of Technology is a education organization based out in Delft, Zuid-Holland, Netherlands. It is known for research contribution in the topics: Computer science & Catalysis. The organization has 37681 authors who have published 94404 publications receiving 2741710 citations. The organization is also known as: TU-Delft & Technische Hogeschool Delft.

PIV-based pressure measurement

Abstract: The topic of this article is a review of the approach to extract pressure fields from flow velocity field data, typically obtained with particle image velocimetry (PIV), by combining the experimental data with the governing equations. Although the basic working principles on which this procedure relies have been known for quite some time, the recent expansion of PIV capabilities has greatly increased its practical potential, up to the extent that nowadays a time-resolved volumetric pressure determination has become feasible. This has led to a novel diagnostic methodology for determining the instantaneous flow field pressure in a non-intrusive way, which is rapidly finding acceptance in an increasing variety of application areas. The current review describes the operating principles, illustrating how the flow-governing equations, in particular the equation of momentum, are employed to compute the pressure from the material acceleration of the flow. Accuracy aspects are discussed in relation to the most dominating experimental influences, notably the accuracy of the velocity source data, the temporal and spatial resolution and the method invoked to estimate the material derivative. In view of its nature of an emerging technique, recently published dedicated validation studies will be given specific attention. Different application areas are addressed, including turbulent flows, aeroacoustics, unsteady wing aerodynamics and other aeronautical applications.

An overview of constraint-based path selection algorithms for QoS routing

Abstract: Constraint-based path selection aims at identifying a path that satisfies a set of quality of service (QoS) constraints. In general, this problem is known to be NP-complete, leading to the proposal of many heuristic algorithms. We provide an overview of these algorithms, focusing on restricted shortest path and multi-constrained path algorithms.

Quantum information processing and communication: strategic report on current status, visions and goals for research in Europe

Abstract: We present an excerpt of the document "Quantum Information Processing and Communication: Strategic report on current status, visions and goals for research in Europe", which has been recently published in electronic form at the website of FET (the Future and Emerging Technologies Unit of the Directorate General Information Society of the European Commission, http://www.cordis.lu/ist/fet/qipc-sr.htm). This document has been elaborated, following a former suggestion by FET, by a committee of QIPC scientists to provide input towards the European Commission for the preparation of the Seventh Framework Program. Besides being a document addressed to policy makers and funding agencies (both at the European and national level), the document contains a detailed scientific assessment of the state-of-the-art, main research goals, challenges, strengths, weaknesses, visions and perspectives of all the most relevant QIPC sub-fields, that we report here.

Electronic structure and magnetism of Fe 3-x V x X (X=Si, Ga, and Al) alloys by the KKR-CPA method

Abstract: We present first-principles charge- and spin-self-consistent electronic structure computations on the Heusler-type disordered alloys ${\mathrm{Fe}}_{3\ensuremath{-}x}{\mathrm{V}}_{x}X$ for three different metalloids $X=(\mathrm{Si},\mathrm{Ga},$ and Al). In these calculations we use the methodology based on the Korringa-Kohn-Rostoker formalism and the coherent-potential approximation generalized to treat disorder in multicomponent complex alloys. Exchange correlation effects are incorporated within the local spin density approximation. Total energy calculations for ${\mathrm{Fe}}_{3\ensuremath{-}x}{\mathrm{V}}_{x}\mathrm{Si}$ show that V substitutes preferentially on the $\mathrm{Fe}(B)$ site, not on the $\mathrm{Fe}(A,C)$ site, in agreement with experiment. Furthermore, calculations have been carried out for ${\mathrm{Fe}}_{3\ensuremath{-}x}{\mathrm{V}}_{x}X$ alloys (with $x=0.25,$ $0.50,$ and $0.75),$ together with the end compounds ${\mathrm{Fe}}_{3}X$ and ${\mathrm{Fe}}_{2}\mathrm{V}X,$ and the limiting cases of a single V impurity in ${\mathrm{Fe}}_{3}X$ and a single $\mathrm{Fe}(B)$ impurity in ${\mathrm{Fe}}_{2}\mathrm{V}X.$ We delineate clearly how the electronic states and magnetic moments at various sites in ${\mathrm{Fe}}_{3\ensuremath{-}x}{\mathrm{V}}_{x}X$ evolve as a function of the V content and the metalloid valence. Notably, the spectrum of ${\mathrm{Fe}}_{3\ensuremath{-}x}{\mathrm{V}}_{x}X$ $(X=\mathrm{Al}$ and Ga) develops a pseudogap for the majority as well as minority spin states around the Fermi energy in the V-rich regime, which, together with local moments of $\mathrm{Fe}(B)$ impurities, may play a role in the anomalous behavior of the transport properties. The total magnetic moment in ${\mathrm{Fe}}_{3\ensuremath{-}x}{\mathrm{V}}_{x}\mathrm{Si}$ is found to decrease nonlinearly, and the $\mathrm{Fe}(B)$ moment to increase with increasing x; this is in contrast to expectations of the ``local environment'' model, which holds that the total moment should vary linearly while the $\mathrm{Fe}(B)$ moment should remain constant. The common-band model, which describes the formation of bonding and antibonding states with different weights on the different atoms, however, provides insight into the electronic structure of this class of compounds.