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Evaluation and application of the Baldwin-Lomax turbulence model in two-dimensional, unsteady, compressible boundary layers with and without separation in engine inlets

There is a practical need to model high speed flows that exist in jet engine inlets. The boundary layers that form in these inlets may be turbulent or laminar and either separated or attached. Also, unsteady supersonic inlets may be subject to frequent changes in operating conditions. Some changes in the operating conditions of the inlets may include varying the inlet geometry, bleeds and bypasses, and rotating or translating the centerbody. In addition, the inlet may be either started or unstarted. Therefore, a CFD code, used to model these inlets, may have to run for several different cases. Also, since the flow conditions through an unsteady inlet may be continually fluctuating, the CFD code which models these flows may have to be run over many time steps. Therefore, it would be beneficial that the code run quickly. Many turbulence models, however, are cumbersome to implement and require a lot of computer time to run, since they add to the number of differential equations to be solved to model a flow. The Baldwin-Lomax turbulence model is a popular model. It is an algebraic, eddy viscosity model. The Baldwin-Lomax model is used in many CFD codes because it is quick and easy to implement. In this paper, we will discuss implementing the Baldwin-Lomax turbulence model for both steady and unsteady compressible flows. In addition, these flows may be either separated or attached. In order to apply this turbulence model to flows which may be subjected to these conditions, certain modifications should be made to the original Baldwin-Lomax model. We will discuss these modifications and determine whether the Baldwin-Lomax model is a viable turbulence model that produces reasonably accurate results for high speed flows that can be found in engine inlets

Second Symposium on Chemical Evolution and the Origin of Life

Recent findings by NASA Exobiology investigators are reported. Scientific papers are presented in the following areas: cosmic evolution of biogenic compounds, prebiotic evolution (planetary and molecular), early evolution of life (biological and geochemical), evolution of advanced life, solar system exploration, and the Search for Extraterrestrial Intelligence (SETI)

Finite temperature effects on the antikaon optical potential

By solving the Bethe-Goldstone equation, we have obtained the $\bar{K}$ optical potential from the $\bar{K}N$ effective interaction in nuclear matter at T=0. We have extended the model by incorporating finite temperature effects in order to adapt our calculations to the experimental conditions in heavy-ion collisions. In the rank of densities ($0-2\rho_0$), the finite temperature $\bar{K}$ optical potential shows a smooth behaviour if we compare it to the T=0 outcome. Our model has also been applied to the study of the ratio between $K^+$ and $K^-$ produced at GSI with $T$ around 70 MeV. Our results point at the necessity of introducing an attractive $\bar{K}$ optical potential.Comment: 7 pages, 4 figures. Contribution to the proceedings of Mesons & Light Nuclei '01 (2-6th July, Prague

Using New Camera-Based Technologies for Gait Analysis in Older Adults in Comparison to the Established GAITRite System

Various gait parameters can be used to assess the risk of falling in older adults. However, the state-of-the-art systems used to quantify gait parameters often come with high costs as well as training and space requirements. Gait analysis systems, which use mobile and commercially available cameras, can be an easily available, marker-free alternative. In a study with 44 participants (age ≥ 65 years), gait patterns were analyzed with three different systems: a pressure sensitive walkway system (GAITRite-System, GS) as gold standard, Motognosis Labs Software using a Microsoft Kinect Sensor (MKS), and a smartphone camera-based application (SCA). Intertrial repeatability showed moderate to excellent results for MKS (ICC(1,1) 0.574 to 0.962) for almost all measured gait parameters and moderate reliability in SCA measures for gait speed (ICC(1,1) 0.526 to 0.535). All gait parameters of MKS showed a high level of agreement with GS (ICC(2,k) 0.811 to 0.981). Gait parameters extracted with SCA showed poor reliability. The tested gait analysis systems based on different camera systems are currently only partially able to capture valid gait parameters. If the underlying algorithms are adapted and camera technology is advancing, it is conceivable that these comparatively simple methods could be used for gait analysis

BOSQUE, Ignacio, ed. (2006): Diccionario combinatorio práctico del español contemporáneo [Reseña]

[Resumen] Reseña de Bosque, Ignacio, ed. (2006): Diccionario combinatorio práctico del español contemporáneo, Madrid, SM

IVOA Recommendation: Data Model for Astronomical DataSet Characterisation

This document defines the high level metadata necessary to describe the physical parameter space of observed or simulated astronomical data sets, such as 2D-images, data cubes, X-ray event lists, IFU data, etc.. The Characterisation data model is an abstraction which can be used to derive a structured description of any relevant data and thus to facilitate its discovery and scientific interpretation. The model aims at facilitating the manipulation of heterogeneous data in any VO framework or portal. A VO Characterisation instance can include descriptions of the data axes, the range of coordinates covered by the data, and details of the data sampling and resolution on each axis. These descriptions should be in terms of physical variables, independent of instrumental signatures as far as possible. Implementations of this model has been described in the IVOA Note available at: http://www.ivoa.net/Documents/latest/ImplementationCharacterisation.html Utypes derived from this version of the UML model are listed and commented in the following IVOA Note: http://www.ivoa.net/Documents/latest/UtypeListCharacterisationDM.html An XML schema has been build up from the UML model and is available at: http://www.ivoa.net/xml/Characterisation/Characterisation-v1.11.xsdComment: http://www.ivoa.ne

Ackerbausysteme im ökologischen Landbau: Untersuchungen zur Nmin-, N2O-N- und NH2-N-Dynamik sowie Rückschlüsse zur Anbau-Optimierung

Die Entwicklung der Landwirtschaft war in den letzten Jahrzehnten gekennzeichnet durch einen beispiellosen Anstieg des Dünge- und Pflanzenschutzmitteleinsatzes sowie durch entsprechend starke Ertragssteigerungen. Die damit verbundenen nachteiligen Umweltwirkungen auf Wasser, Boden und Atmosphäre führten einerseits zur Suche nach Optimierungsstrategien und andererseits zu erhöhten Anstrengungen bei der Prüfung alternativer Bewirtschaftungsformen. Zur Prüfung von Ackerbausystemen des ökologischen Landbaus wurden ab dem Jahr 1992 komplexe Dauerversuche angelegt. Es wurden Verfahren von viehlosen sowie von viehhaltenden Betrieben simuliert. In den Versuchen wurden außerdem eine stark unterschiedliche Düngungshöhe mit verschiedenen organischen Düngemitteln sowie differenzierte anbautechnische und vegetationsbegleitende Maßnahmen berücksichtigt. Die Anbauverfahren wurden sowohl in ihren kurzzeitigen Auswirkungen auf Nährstoffdynamik, Ertrag und Produktqualität der Kulturarten als auch in ihren langfristigen Auswirkungen auf die Nährstoffbilanzen der Fruchtfolgen sowie auf die Bodenfruchtbarkeit geprüft. Diese Veröffentlichung dokumentiert die komplexen Dauerversuche, mit deren Hilfe es möglich ist, pflanzenbauliche Optimalvarianten zu ermitteln, die eine dauerhafte Anwendung ermöglichen

Use of W-Boson Longitudinal-Transverse Interference in Top Quark Spin-Correlation Functions: II

This continuation of the derivation of general beam-referenced stage-two spin-correlation functions is for the analysis of top-antitop pair-production at the Tevatron and at the Large Hadron Collider. Both the gluon-production and the quark-production contributions are included for the charged-lepton-plus-jets reaction p p or p bar{p} --> t bar{t} --> (W^+ b)(W^- bar{b}) --> (l^{+} nu b)(W^- bar{b}). There is a simple 4-angle beam-referenced spin-correlation function for determination of the relative sign of, or for measurement of a possible non-trivial phase between the two dominant helicity amplitudes for t --> W^{+} b decay. There is an analogous function and tests for bar{t} --> W^{-} bar{b} decay. This signature requires use of the (t bar{t}) c.m.-energy of the hadronically decaying W-boson, or the kinematically equivalent cosine of the polar-angle of W-boson emission in the anti-top (top) decay frame. Spinors and their outer-products are constructed so that the helicity-amplitude phase convention of Jacob & Wick can be used throughout for the fixing of the signs associated with this large W-boson longitudinal-transverse interference effect.Comment: Continuation of hep-ph/0506240 to include gluon-production contribution; 3 "postscript" figures. Equation numbers as in published-on-line EPJ