Coupling tabulated chemistry with Large Eddy Simulation of turbulent reactive flows

A new modeling strategy is developed to introduce tabulated chemistry methods in the LES of turbulent premixed combustion. The objective is to recover the correct laminar flame propagation speed of the filtered flame front when the subgrid scale turbulence vanishes. The filtered flame structure is mapped by 1D filtered laminar premixed flames. Closure of the filtered progress variable and the energy balance equations are carefully addressed. The methodology is applied to 1D and 2D filtered laminar flames. These computations show the capability of the model to recover the laminar flame speed and the correct chemical structure when the flame wrinkling is completely resolved. The model is then extended to turbulent combustion regimes by introducing subgrid scale wrinkling effects on the flame front propagation. Finally, the LES of a 3D turbulent premixed flame is performed. To cite this article: R. Vicquelin et al., C. R. Mecanique 337 (2009).     

Fractal geometry and topology abstracted from hair fibers

Based on the concepts of fractal super fibers, the （3, 9＋2）-circle and （9＋2, 3）-circle binary fractal sets are abstracted form such prototypes as wool fibers and human hairs, with the （3）-circle and the （9＋2）-circle fractal sets as subsets. As far as the （9＋2） topological patterns are concerned, the following propositions are proved： The （9＋2） topological patterns accurately exist, but are not unique. Their total number is 9. Among them, only two are allotropes. In other words, among the nine topological patterns, only two are independent （or fundamental）. Besides, we demonstrate that the （3, 9＋2）-circle and （9＋2, 3）-circle fractal sets are golden ones with symmetry breaking.     

Untersuchungen zur Cyclisierung von „3-Aza-1,5-dicarbonylverbindungen”

From1b, 1c and1d no 1,4-oxazines are available under dehydrating conditions. Only reaction of1c withPPA at room temperature yields7, while1 d in dependence of the reaction time withPPA at 100°C undergoes cyclisation to the indoles3 b and3 c and the pyrroloindole4 b, resp.

Teile der DiplomarbeitHaubold G., Wien 1977. Teile der DissertationHaubold G., Wien 1980.     

3-甲基丙烯酰胺基-9-乙基咔唑/过硫酸钾体系引发丙烯酰胺聚合

合成了可聚合芳香叔胺 - 3 甲基丙烯酰胺基 9 乙基咔唑 ,并与过硫酸钾组成氧化还原引发体系引发丙烯酰胺水溶液聚合 ,测定了聚合反应动力学 ,得到了超高分子量的聚丙烯酰胺。     

Synthesis and photophysics of acridine derivatives

Highly fluorescent acridine derivatives were prepared by a multistep synthesis starting from 2-chlorobenzoic acid and the approapriate (aminophenyl)alkanoic acid by means of a modified Ullmann-Jourdan reaction followed by a cyclodehydration step, and by amination in the case of aminoacridine analogues. The obtained derivatives were subjected to photophysical studies (absorption and fluorescence). The compounds displayed interesting absorption behavior and high quantum yield of fluorescence. Acridine analogues bearing a free carboxylic group can serve as effective fluorescent probes in conformation analysis of peptides.Faculty of Chemistry, University of Gdansk, Sobieskiego 18 80-952, Gdansk, Poland; e-mail: neta@chemik.chem.univ.gda.pl Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 914–921, July, 2000.     

Hyperfine anomaly for the ground state of 9Be+

The Fermi contact parameter which represents hyperfine structure (hfs) has been accurately calculated for the ground state of the ⁹Be⁺ ion in a previous paper. In the present paper, the calculated parameter is compared with a high precision measurement to derive the hfs anomaly (the Bohr-Weisskopf effect), which is caused by nuclear magnetization distribution. The obtained hfs anomaly shows a satisfactory agreement with the result of a nuclear shell model calculation. This revised version was published online in August 2006 with corrections to the Cover Date.     

Oscillatory fracture paths in thin elastic sheets

We report a novel mode of quasi-static oscillatory crack propagation when a cutting tip of moderately large width is driven through a thin brittle polymer film. Experiments show that the amplitude and wavelength of the oscillatory crack paths scale linearly with the width of the cutting tip over a wide range of length scales but are independent of the width of the sheet and of the cutting speed. We propose a mechanism for this instability, based on the coupling between crack propagation and out-of-plane deformations of the film. To cite this article: B. Roman et al., C. R. Mecanique 331 (2003).     

Ca_3Co_4O_9热电材料前驱体制备及性能表征

分别采用固相反应法和空间俘获法制备了Ca3Co4O9前驱体,并经冷等静压后常压烧结工艺制备了块体陶瓷样品。利用TG-DSC、XRD、SEM等方法对前驱体进行了表征,同时测试了陶瓷样品的热电性能。结果表明:空间俘获法可获得纯相、晶粒较小的前驱粉体,同时降低了合成温度,而且合成样品的Seebeck系数和功率因子明显高于固相反应法。在976 K获得最大Seebeck系数和功率因子分别为179μV/K、7.5×10–7 W/(cm·K2),较固相反应优化60%、16倍;电阻率略有升高。     

Ageing characteristics of the metastable gamma phase in U–9 wt.% Mo alloy: experimental observations and thermodynamic validation

Ageing characteristics of the metastable bcc γ-phase in U–9 wt.% Mo alloy, a candidate for high uranium density nuclear fuel for research and test reactors, have been investigated in this study. Analyses of the aged microstructures, employing X-ray diffraction and various microscopy techniques, revealed the decomposition mechanism of the metastable γ-phase to the stable α-U and γ′ (U₂Mo) phases. A discontinuous precipitation reaction, leading to the generation of partially transformed cellular colonies with lamellae comprising of either the α-phase or the γ′-phase in γ-phase matrix, was found to be operative. The in situ transformation of γ interlamellar regions to the γ′-phase was noticed occasionally within the γ + α lamellar colonies. Thermodynamic analysis of the U–Mo system, using free energy–composition diagrams, could associate the observed attributes of the decomposition of γ-phase to the extent of Mo segregation and the chemical driving force required for the nucleation of α- and γ′-phases in the γ-matrix.