179,058 research outputs found
A two-dimensional structural-acoustic radiation benchmark
No full textA two-dimensional finite element (FE) model is presented, which can be used to validate methods and design criterions for vibroacoustics. A simple beam-like structure, providing different transmission paths for some structure-borne point excitation, is connected to a beam. The latter is acting as a radiator. The acoustic fluid is modeled by means of acoustic elements, and two different boundary conditions are implemented. This results in one model providing free-field conditions (halfspace) and one with a reverberant setting. The model, therefore, enables one to analyze a full acoustic chain of effects (transmission of vibration through the structure and radiation) in a sufficiently complex setting with moderate model size. For an application and a more detailed description of the model see:Sicklinger S. and Ullmann, R.: "Structural power as an acoustic design criterion for the early phase of product design", International Conference on Noise and Vibration Engineering, Leuven, 2018
Data for: Validation of a Uniaxial Structure-Borne Sound Benchmark With Emphasis on Power and Phase Accuracy
No full textData in order to reproduce the benchmark of the associated publication "Validation of a Uniaxial Structure-Borne Sound Benchmark with Emphasis on Power and Phase Accuracy". The dataset contains:1. Geometry data The geometry of the single parts of the benchmark structure provided as STEP-files.2. FE data ASCII FE representation for the benchmark (SIMULIA Abaqus input file syntax)3. Measurement data Data files containing the results of the measurements, which were used for generating the Figures contained in the publicatio
Oligopyrroles by the Ullmann coupling
No full textOligomers were obtained by the Ullmann coupling of N-(tert-butoxycarbonyl)-2,5-dibromopyrrole. The dimerization of 2-bromo-N-(tert-butoxycarbonyl)-5-phenylpyrrole was studied as a model reaction. [on SciFinder (R)
A 3D solid beam benchmark for parametric model order reduction
No full textA 3D solid beam benchmark is provided for benchmarking parametric model order reduction methods, for example.
The example consists of solid brick FE elements and kinematic couplings, thus industry relevant modeling.
Using sampled system matrices from Simulia ABAQUS, an affine matrix decomposition is recalculated, which preserves ten variable input parameters
Data for: Validation of a Structure-Borne Sound Benchmark With Emphasis on Power and Phase Accuracy
No full textData in order to reproduce the benchmark of the associated publication "Validation of a Structure-Borne Sound Benchmark with Emphasis on Power and Phase Accuracy". The dataset contains: 1.Geometry data The geometry of the single parts of the benchmark structure provided as STEP-files. 2.FE data ASCII FE representation for the benchmark (SIMULIA Abaqus input file syntax)3.Measurement data Data files containing the results of the measurements, which were used for generating the Figures contained in the publicatio
Sea Surges in Camargue: Trends over the 20th century.
No full textContinental Shelf Research 27 (2007) 922–934
Sea surges in Camargue: Trends over the 20th century
A. Ullmanna,b,, P.A. Pirazzolic, A. Tomasind,e
aUFR des Sciences Ge´ographiques et de l’Ame´nagement, Universite´ d’Aix-Marseille I, Aix en -Provence, France
bCEREGE—UMR 6635, Aix en Provence, France
cCNRS-Laboratoire de Ge´ogrphie Physique, 1 place Aristide Briand, 92 195-Meudon, France
dCNR-ISMAR, Venezia, Italy
eUniversita` di Venezia, Venezia, Italy
Received 8 November 2005; received in revised form 24 November 2006; accepted 4 December 2006
Available online 25 January 2007
Abstract
The vulnerability to short-term and long-term sea-level rises is particularly high in subsiding deltaic areas, especially in
microtidal seas, when surges (the differences between the observed sea heights and the simultaneous astronomical tide) are
frequent. At the Grau-de-la-Dent tide-gauge in the Camargue (Rhone delta, France), daily sea-level records are available
since 1905. Hourly tide data spanning the period 1979–1995 were obtained through the digitisation of the original paper
records: the local harmonic constants and the surges for the whole 20th century have been computed from these hourly
observations. It appears that the annual maximum observed sea-level height increases by 4 mm/yr at a rate that is two
times faster than the average observed relative sea level. The increasing trend of the annual maximum positive sea surges
(+1.9 mm/yr), which is equal to the average relative sea-level rise, is thus responsible for this difference. The most
important meteorological factor associated with local sea-surge occurrences is wind blowing from 1001 to 1201 sectors,
which tends to push the water toward the coasts. Since 1961, the frequency and the speed of wind from this sector
increased, although with some variability, thus contributing in part to the increase in the frequency and intensity of the
surges. Due to the changing hydrodynamics phenomenon in the Camargue, a positive feedback mechanism between
extreme marine events and shoreline regression is another factor to explain the sea-surge rise over the long term. The
increase in sea-surge frequency and height during the last century is especially of concern in the deltaic area if the nearfuture
global sea-level rise predicted by climate models is also taken into account.
r 2007 Elsevier Ltd. All rights reserved.
Keywords: Sea level; Surge; Tide; Wind; Flooding risk; Camargue; Rhone delta
1. Introduction
Any rise in sea level will have adverse impacts
such as coastal erosion and flooding, depending on
the time scale and the magnitude of the rise and the
human response to it (Paskoff, 1993). A rise in sea
level may be due to several factors acting on various
time scales, i.e., atmospheric storms (Bouligand and
Pirazzoli, 1999; Pirazzoli, 2000; Trigo and Davies,
2002; Pirazzoli and Tomasin, 2002), river flooding
in estuaries (Svensson and Jones, 2002), but also
land sinking or similar non climate-related changes,
linked to sediment compaction, isostasy, coastal
geomorphologic evolutions or urban development.
ARTICLE IN PRESS
www.elsevier.com/locate/csr
0278-4343/$ - see front matter r 2007 Elsevier Ltd. All rights reserved.
doi:10.1016/j.csr.2006.12.001
Corresponding author. CEREGE, Europoˆ le Me´diterrane´en
de l’Arbois, B.P 80, 13545 Aix-en-Provence, France.
E-mail address: [email protected] (A. Ullmann)
Respiratory compliance but not gas exchange correlates with changes in lung aeration after a recruitment maneuver: an experimental study in pigs with saline lavage lung injury
No full textINTRODUCTION:
Atelectasis is a common finding in acute lung injury, leading to increased shunt and hypoxemia. Current treatment strategies aim to recruit alveoli for gas exchange. Improvement in oxygenation is commonly used to detect recruitment, although the assumption that gas exchange parameters adequately represent the mechanical process of alveolar opening has not been proven so far. The aim of this study was to investigate whether commonly used measures of lung mechanics better detect lung tissue collapse and changes in lung aeration after a recruitment maneuver as compared to measures of gas exchange
METHODS:
In eight anesthetized and mechanically ventilated pigs, acute lung injury was induced by saline lavage and a recruitment maneuver was performed by inflating the lungs three times with a pressure of 45 cmH2O for 40 s with a constant positive end-expiratory pressure of 10 cmH2O. The association of gas exchange and lung mechanics parameters with the amount and the changes in aerated and nonaerated lung volumes induced by this specific recruitment maneuver was investigated by multi slice CT scan analysis of the whole lung.
RESULTS:
Nonaerated lung correlated with shunt fraction (r = 0.68) and respiratory system compliance (r = 0.59). The arterial partial oxygen pressure (PaO2) and the respiratory system compliance correlated with poorly aerated lung volume (r = 0.57 and 0.72, respectively). The recruitment maneuver caused a decrease in nonaerated lung volume, an increase in normally and poorly aerated lung, but no change in the distribution of a tidal breath to differently aerated lung volumes. The fractional changes in PaO2, arterial partial carbon dioxide pressure (PaCO2) and venous admixture after the recruitment maneuver did not correlate with the changes in lung volumes. Alveolar recruitment correlated only with changes in the plateau pressure (r = 0.89), respiratory system compliance (r = 0.82) and parameters obtained from the pressure-volume curve.
CONCLUSION:
A recruitment maneuver by repeatedly hyperinflating the lungs led to an increase of poorly aerated and a decrease of nonaerated lung mainly. Changes in aerated and nonaerated lung volumes were adequately represented by respiratory compliance but not by changes in oxygenation or shunt
A mathematical view on the decoupled sites representation
No full textThe decoupled sites representation (DSR) is a theoretical instrument which allows to regard complex pH titration curves of biomolecules with several interacting proton binding sites as composition of isolated, non-interacting sites, each with a standard Henderson-Hasselbalch titration curve. In this work, we present the mathematical framework in which the DSR is embedded and give mathematical proofs for several statements in the periphery of the DSR. These proofs also identify exceptions. To apply the DSR to any molecule, it is necessary to extend the set of binding energies from to a stripe within . An important observation in this context is that even positive interaction energies (repulsion) between the binding sites will not guarantee real binding energies in the decoupled system, at least if the molecule has more than four proton binding sites. Moreover, we show that for a given overall titration curve it is not only possible to find a corresponding system with an interaction energy of zero but with any arbitrary fix interaction energy. This result also effects practical work as it shows that for any given titration curve, there is an infinite number of corresponding hypothetical molecules. Furthermore, this implies that-using a common definition of cooperative binding on the level of interaction energies-a meaningful measure of cooperativity between the binding sites cannot be defined solely on the basis of the overall titration. Consequently, all measures of cooperativity based on the overall binding curve do not measure the type of cooperativity commonly defined on the basis of interaction energies. Understanding the DSR mathematically provides the basis of transferring the DSR to biomolecules with different types of interacting ligands, such as protons and electrons, which play an important role within electron transport chains like in photosynthesis.Deutsche Forschungsgemeinschaft [SFB 840
Optical probe study of a nonentangling macromolecule solution--bovine serum albumin: Water
No full textThe diffusion coefficient D of polystyrene latex spheres in bovine serum albumin:water was studied as a function of protein concentration c for 0 c D fails by as much as 25 to 50%, D being larger than predicted from the sphere radius R and the solution viscosity. Probe particles with R as large as 0.62 [mu]m were used. D fits well to the form D = Doexp(-[alpha]cv) for [alpha] = 0.004 to 0.008 and v = 0.96 to 0.99. Serum albumin is a globular protein, so chain entanglement cannot cause these non-Stokes--Einsteinian effects, which are presumably due to sphere:albumin interactions. Polystyrene spheres in semidilute polyethylene oxide:water (G. S. Ullmann, K. Ullmann, R. M. Lindner, and G. D. J. Phillies, J. Phys. Chem. 89, 692 (1985)) behave similarly to spheres in serum albumin:water, suggesting that chain entanglement may also not be important in probe diffusion through semidilute polymer solutions.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/25653/1/0000205.pd
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