57,105 research outputs found
Dachziegelwerk und Tonwarenfabrik Hans Denol, Straubing empfiehlt als Specialität - Dachdeckungsmaterial in prima Qualitäten wie Biberschwanzplatten halbkreis- u. segmentförmig, Strangsalzziegel, Turm- u. Trausplatten, Firstziegel etc. Ferner Mauersteine Bayr. u. Reichs.- Format, Lochsteine poröse Steine, Hourdis- u. Drainageröhren usw.
No full textDACHZIEGELWERK UND TONWARENFABRIK HANS DENOL, STRAUBING EMPFIEHLT ALS SPECIALITÄT - DACHDECKUNGSMATERIAL IN PRIMA QUALITÄTEN WIE BIBERSCHWANZPLATTEN HALBKREIS- U. SEGMENTFÖRMIG, STRANGSALZZIEGEL, TURM- U. TRAUSPLATTEN, FIRSTZIEGEL ETC. FERNER MAUERSTEINE BAYR. U. REICHS.- FORMAT, LOCHSTEINE PORÖSE STEINE, HOURDIS- U. DRAINAGERÖHREN USW.
Dachziegelwerk und Tonwarenfabrik Hans Denol, Straubing empfiehlt als Specialität - Dachdeckungsmaterial in prima Qualitäten wie Biberschwanzplatten halbkreis- u. segmentförmig, Strangsalzziegel, Turm- u. Trausplatten, Firstziegel etc. Ferner Mauersteine Bayr. u. Reichs.- Format, Lochsteine poröse Steine, Hourdis- u. Drainageröhren usw. ( -
Ranging with ultrawide bandwidth signals in multipath environments
No full textOver the coming decades, high-definition situationally-aware networks have the potential to create revolutionary applications in the social, scientific, commercial, and military sectors. Ultrawide bandwidth (UWB) technology is a viable candidate for enabling accurate localization capabilities through time-of-arrival (TOA)-based ranging techniques. These techniques exploit the fine delay resolution property of UWB signals by estimating the TOA of the first signal path. Exploiting the full capabilities of UWB TOA estimation can be challenging, especially when operating in harsh propagation environments, since the direct path may not exist or it may not be the strongest. In this paper, we first give an overview of ranging techniques together with the primary sources of TOA error (including propagation effects, clock drift, and interference). We then describe fundamental TOA bounds (such as the Cramer-Rao bound and the tighter Ziv-Zakai bound) in both ideal and multipath environments. These bounds serve as useful benchmarks in assessing the performance of TOA estimation techniques. We also explore practical low-complexity TOA estimation techniques and analyze their performance in the presence of multipath and interference using IEEE 802.15.4a channel models as well as experimental data measured in indoor residential environments.FP7 European Project EUWB (Grant 215669)Institute of Advanced Study Natural Science and Technology FellowshipUniversità di FerraraUnited States. Office of Naval Research (Young Investigator Award N00014-03-1-0489)National Science Foundation (U.S.) (Grant ANI-0335256)National Science Foundation (U.S.) (Grant ECS-0636519)Jet Propulsion Laborator
Francis Ferner : La prédestination. Coll. Que sais-je ?. Paris, P. U. F. 1990
No full textAndré Birmelé. Francis Ferner : La prédestination. Coll. Que sais-je ?. Paris, P. U. F. 1990. In: Revue d'histoire et de philosophie religieuses, 71e année n°4, Octobre-décembre 1991. pp. 488-489
A Dynamic Subfilter-scale Stress Model for Large Eddy Simulations Based on Physical Flow Scales
No full textWe propose a new definition of the length scale in an eddy-viscosity model for large-eddy simulations (LES). This formulation extends and generalizes a previous proposal [Piomelli, Rouhi and Geurts, Proc. ETMM10, 2014], in which the LES length scale was expressed in terms of the integral length-scale of turbulence determined by the flow characteristics and explicitly decoupled from the simulation grid; this approach was named Integral Length-Scale Approximation (ILSA). As in the original ILSA, the model coefficient was determined by the user, and required to maintain a desired contribution of the unresolved, subfilter scales (SFS) to the global transport. We propose a local formulation (local ILSA) in which the model coefficient is local in space, allowing a precise control over SFS activity as a function of location. This new formulation preserves the properties of the global model; application to channel flow and backward-facing step verifies its features and accuracy
Large-eddy simulation of a separated flow with a sub-filter scale model based on the integral length-scale
No full textA new sub-filter scale model for large-eddy simulations, which uses a length-scale proportional to the integral scale of the turbulence instead of the grid resolution to parametrize the modelled stresses, will be assessed in the prediction of the flow of a boundary-layer over a rough surface, which includes separation and reattachment
Near Wall PIV-Measurements on the Windward Slope of a Hill
No full textThe turbulent flow over periodic hills was measured near to the wall, using planar Particle-Image-Velocimetry (PIV) at high spatial resolution. Our focus is on the near wall turbulence structure on the windward slope of the hill. For large-eddy simulation (LES) we suspect that, if this was not predicted accurately, it affects the prediction of the velocity profiles over the hill crest which in turn will affect the recirculation length downstream of the hill. Regarding the time averaged velocities, we were able to resolve the linear viscous region of the boundary layer. The velocity distribution and also the Reynolds stress does not comply with the law of the wall as it is valid for a turbulent boundary layer at equilibrium
Energy dissipation and flux laws for unsteady turbulence
No full textDirect Numerical Simulations of spatially periodic unsteady turbulence show that the high Reynolds number scalings of the instantaneous energy dissipation rate and interscale energy flux at intermediate wavenumbers are qualitatively different from the well-known cornerstone scalings of equilibrium turbulence where and are time-dependent rms velocity and integral length-scales. Instead, they both scale as where and are length and velocity scales characterizing initial/overall unsteady turbulence conditions
Direct numerical simulation of turbulent Couette-Poiseuille flow with zero skin friction
No full textThe near-wall scaling of mean velocity U(y) is addressed for the case of zero skin friction on one wall of a fully turbulent channel flow. The present DNS results can be added to the evidence in support of the conjecture that U is proportional to √yw in the region just above the wall at which the mean shear dU/dy = 0
Real-space Manifestations of Bottlenecks in Turbulence Spectra
No full textAn energy-spectrum bottleneck, a bump in the turbulence spectrum between the inertial and dissipation ranges, is shown to occur in the non-turbulent, one-dimensional, hyperviscous Burgers equation and found to be the Fourier-space signature of oscillations in the real-space velocity, which are explained by boundary-layer-expansion techniques. Pseudospectral simulations are used to show that such oscillations occur in velocity correlation functions in one- and three-dimensional hyperviscous hydrodynamical equations that display genuine turbulence
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