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71.
72.
Felix Jaegle Olivier Cabrit Simon Mendez Thierry Poinsot 《Flow, Turbulence and Combustion》2010,85(2):245-272
Two different implementation techniques of wall functions for cell-vertex based numerical methods are described and evaluated.
The underlying wall model is based on the classical theory of the turbulent boundary layer. The present work focuses on the
integration of this wall-model in a cell-vertex solver for large eddy simulations and its implications when applied to complex
geometries, in particular domains with sudden expansions (more generally in presence of sharp edges). At corner nodes, the
conjugation of law of the wall models using slip velocities on walls and of the cell-vertex approach leads to difficulties.
Therefore, an alternative implementation of wall functions is introduced, which uses a no-slip condition at the wall. Both
implementation methods are compared in a turbulent periodic channel flow, representing a typical validation case. The case
of an injector for aero-engines is presented as an example for an industrial-scale application with a complex geometry. 相似文献
73.
Ecklund KM Love W Savinov V Lopez A Mendez H Ramirez J Ge JY Miller DH Shipsey IP Xin B Adams GS Anderson M Cummings JP Danko I Hu D Moziak B Napolitano J He Q Insler J Muramatsu H Park CS Thorndike EH Yang F Artuso M Blusk S Khalil S Li J Mountain R Nisar S Randrianarivony K Sultana N Skwarnicki T Stone S Wang JC Zhang LM Bonvicini G Cinabro D Dubrovin M Lincoln A Rademacker J Asner DM Edwards KW Naik P Reed J Briere RA Ferguson T Tatishvili G Vogel H Watkins ME Rosner JL Alexander JP 《Physical review letters》2008,100(16):161801
Using a sample of tagged D(s)(+) decays collected near the D(s)(*+/-)D(s)(-/+) peak production energy in e(+)e(-) collisions with the CLEO-c detector, we study the leptonic decay D(s)(+)-->tau(+)nu(tau) via the decay channel tau(+)-->e(+)nu(e)nu(tau). We measure B(D(s)(+)-->tau(+)nu(tau))=(6.17+/-0.71+/-0.34)%, where the first error is statistical and the second systematic. Combining this result with our measurements of D(s)(+)-->mu(+)nu(mu) and D(s)(+)-->tau(+)nu(tau) (via tau(+)-->pi(+)nu(tau)), we determine f(D(s))=(274+/-10+/-5) MeV. 相似文献
74.
J.L. Perez Pavon B. Moreno Cordero E. Rodriguez Garcia Hernandez Mendez 《Analytica chimica acta》1990
The determination of uranium by a flow system with reagent injection is based on the reaction of U(IV) with Arsenazo III in 3.6 M HCl; U(IV) is generated by reduction of uranyl ion in a lead reductor minicolumn installed in the sample channel of the manifold. The interference effect caused by several ions is studied. The calibration graph is linear up to 1.0 × 10?5 M (2.4 mg l?1) and the detection limit is 2.8 × 10?8 M (6.6 μg l?1). The modification of the manifold by including a second valve to by-pass the reducing column allows the measurement of the difference in peak heights, which makes the method specific for uranium. 相似文献
75.
A study has been made of the polarographic (DC and DPP) behaviour of the food dyes Sunset Yellow and Tartrazine in acid and alkaline media and in the absence and presence of polyvinylpyrrolidone. Methods are proposed for the determination of both dyes by DPP over a concentration range of 0.1-10 ppm. The methods have been applied to their determination in soft drinks. 相似文献
76.
The effects of different concentrations of several volatile organic compounds (VOC) such as ethanol, acetate, propionate,
and butyrate ranging from 0 to 2000 mg/L as well as a mixture of volatile fatty acids (MVFA) at a 4:1:1 (acetate:propionate:butyrate)
ratio on the nitrification rate in batch cultures were studied. The results showed that ethanol and acetate were consumed
in a mixotrophic way by the nitrifying sludge. At a concentration of 500 mg/L, the nitrification rate of inhibition was different
for each compound in which propionate and butyrate were the most inhibitory. At 2000 mg/L the inhibition was 80% with ethanol
and 100% with acetate, propionate, and butyrate. With similar concentrations of MVFA, the inhibition was also similar to that
in acetate. The effect of the addition of pulses of MVFA at a ratio of 4:1:1 during 14 h on the performance of the continuous
nitrifying process with a hydraulic retention time of 3 d was also studied. No inhibition of the nitrification process was
observed with pulses of 750–3000 mg of MVFA/L in the input of the reactor. The results in batch cultures suggest that the
different degrees of inhibition of the nitrification process were related to the type of organic matter added. The noninhibitory
effect of the organic matter in the continuous cultures on the nitrification efficiency of the nitrifying sludge might be
related to the feeding pattern. 相似文献
77.
Analytical chemistry of unusual oxidation states: the polarography of vanadium(IV) in cyanide medium
The polarographic reduction wave for vanadium(IV) in cyanide medium has been studied and the effect of cyanide concentration on the diffusion current and half-wave potential has been interpreted, using the theory of irreversible but diffusion-controlled reduction. Coulometric experiments suggest a two-electron transfer, and the shift of half-wave potential corresponds to the addition of one cyanide ion during the reduction step. The proportionality of wave-height to vanadium concentration in the used alkaline cyanide medium indicates a possible analytical unity. The half-wave potential is about -1.1 V. 相似文献
78.
A. Sanchez Perez M. Delgado Zamarreño J. Hernandez Mendez R.M. Sanchez Rodriguez 《Analytica chimica acta》1989
A simple, rapid and sensitive flow-injection method with amperometric detection for the determination of vitamin D3 and 25-hydroxy-vitamin D3 (25-OH-D3) in pharmaceutical preparation is described. The method is based on the anodic electrochemical behaviour of these substances in methanol-water using a glassy carbon electrode. The optimum working potential was + 1.050 V (vs. Ag/AgCl). The influence of flow-rate, coil length and injection volume on sensitivity was established. Calibration graphs for both vitamin D3 and 25-OH-D3 show good linearity in the range 1.8×10?7?1.0×10?5 M. Detection limits of 7 ng (vitamin D3) and 11 ng (25-OH-D3) and relative standard deviations of 1.5% were obtained. 相似文献
79.
Differentiation of Human Mesenchymal Stem Cells Toward Quality Cartilage Using Fibrinogen‐Based Nanofibers 下载免费PDF全文
80.
Dobbs S Metreveli Z Seth KK Tomaradze A Zweber P Ernst J Mahmood AH Severini H Asner DM Dytman SA Love W Mehrabyan S Mueller JA Savinov V Li Z Lopez A Mendez H Ramirez J Huang GS Miller DH Pavlunin V Sanghi B Shibata EI Shipsey IP Adams GS Chasse M Cravey M Cummings JP Danko I Napolitano J Cronin-Hennessy D Park CS Park W Thayer JB Thorndike EH Coan TE Gao YS Liu F Artuso M Boulahouache C Blusk S Butt J Dambasuren E Dorjkhaidav O Menaa N Mountain R Muramatsu H Nandakumar R Redjimi R Sia R 《Physical review letters》2005,94(3):032004
We report on a search for the recently reported X(3872) state using 15.1 fb(-1) of e(+)e(-) data taken in the sqrt[s] = 9.46-11.30 GeV region. Separate searches for the production of the X(3872) in untagged gammagamma fusion and e(+)e(-) annihilation following initial state radiation are made by taking advantage of the unique angular correlation between the leptons from the decay J/psi --> l(+)l(-) in X(3872) decay to pi(+)pi(-)J/psi. No signals are observed in either case, and 90% confidence upper limits are established as (2J+1)Gamma(gammagamma)(X(3872))B(X --> pi(+)pi(-)J/psi) < 12.9 eV and Gamma(ee)(X(3872))B(X- -> pi(+)pi(-)J/psi) < 8.3 eV. 相似文献