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41.
Patrick Landais Jean-Fran ois Muller Raymond Michels Jean-Louis Oudin Patrick Zaugg 《Fuel》1989,68(12):1616-1619
A series of experiments were performed in cold-seal autoclaves (confined-pyrolysis) to characterize the behaviour of individual macerais (vitrinite, inertinite, exinite) extracted from the same Lorraine Basin coal during artificial coalification. Rock-Eval pyrolysis, elemental analysis and weight loss determination provided the simple maturation indexes required. Emphasis was laid on the timing of hydrocarbon generation and on the possible similarities existing between inertinite and vitrinite of higher rank. Hydrocarbon potential and hydrocarbon yield were found to increase from inertinite to vitrinite and exinite, but similar mechanisms were involved during the thermal degradation of both inertinite and vitrinite. 相似文献
42.
Pierre Rossi Jean Philippe Charron Maléna Bastien-Masse Jean-Louis Tailhan Fabrice Le Maou Sandrine Ramanich 《Materials and Structures》2014,47(10):1773-1785
The paper presents experimental results concerning the comparison of tensile and compressive basic creep behaviours at early ages of two different concretes: a normal strength concrete (NSC) and a very high strength fibre reinforced concrete (HPFRC). This research project has been done in the context of a bilateral collaboration between Polytechnique Montreal and IFSTTAR. Observations on the HPFRC showed specific compressive creep similar to the specific tensile creep. Moreover, the specific creep curves obtained under compressive and tensile loading had always positive values, i.e. they were in same direction of the applied load on specimens. Measurements made on the NSC revealed specific compressive creep with positive values (in the loading direction). However, specific tensile creep presented negative values (opposite direction of loading) for a long period. A physical explanation based on the existence of two mechanisms with opposite effect is proposed to describe these basic creep results. The first mechanism is a coupling between the microcracking process and the water transfers that lead to additional self-drying shrinkage; the second mechanism is the self-healing of concrete induced by the microcracking. 相似文献
43.
Predicting the Thermal Conductivity of AlSi/Polyester Abradable Coatings: Effects of the Numerical Method 总被引:1,自引:0,他引:1
Rodolphe Bolot Jean-Louis Seichepine Jiang Hao Qiao Christian Coddet 《Journal of Thermal Spray Technology》2011,20(1-2):39-47
The final target of this study is to achieve a better understanding of the behavior of thermally sprayed abradable seals such as AlSi/polyester composites. These coatings are used as seals between the static and the rotating parts in aero-engines. The machinability of the composite coatings during the friction of the blades depends on their mechanical and thermal effective properties. In order to predict these properties from micrographs, numerical studies were performed with different software packages such as OOF developed by NIST and TS2C developed at the UTBM. In 2008, differences were reported concerning predictions of effective thermal conductivities obtained with the two codes. In this article, a particular attention was paid to the mathematical formulation of the problem. In particular, results obtained with a finite difference method using a cell-centered approach or a nodal formulation allow explaining the discrepancies previously noticed. A comparison of the predictions of the computed effective thermal conductivities is thus proposed. This study is part of the NEWAC project, funded by the European Commission within the 6th RTD Framework programm (FP6). 相似文献
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45.
Alain BissonierChristian Chauveau Jean-Louis DelfauChristian Vovelle Yolanda Diaz De Mera 《Combustion and Flame》2002,129(3):239-252
An experimental study of the combustion of technical 1,2,3,4-tetrachlorobenzene has been carried out in conditions closely similar to those in incinerators of industrial hazardous wastes. A non-premixed flame fed by a fuel spray was stabilized in a reactor heated electrically. Measurements of axial and radial temperatures and species concentration profiles in well-defined conditions have been systematically repeated to specify the influence exerted by key parameters on the efficiency of the thermal degradation process. The reactor’s wall temperature was varied from 1223 to 1363 K. Air injection was distributed between axial and peripheral injectors to change the swirl intensity. Two fuel injectors have been compared to assess the influence of atomization efficiency. A methane-air pilot flame helped to anchor the flame and to decrease the overall Cl/H ratio. The latter was also decreased by addition of water vapor. Results show that conditions leading to a complete consumption of the fuel can be associated with very limited carbon conversion into CO2 and chlorine conversion into HCl. 相似文献
46.
Amadou D. Diop Emil Ceanga Jean-Louis Rtiveau Jean-Franois Mthot Adrian Ilinca 《Renewable Energy》2007,32(13):2268-2290
This paper deals with the methods of three-dimensional fixed-point wind speed real-time simulation modelled in large band, in order to use them in test rigs for experimental investigation of the wind energy conversion systems. The medium- and long-term components of the non-stationary wind speed are considered as known, being issued from measured data or by adopting a generic model. The spectral characteristics of three-dimensional turbulence are described either by the Kaimal or the von Karman models. The turbulence intensity and the length scale that take part in these models are calculated by the site parameters, using current standards. The basic idea of the methods for large-band three-dimensional wind simulation is to use rational shaping filters that approximate non-integer orders shaping filters issued from the Kaimal and the von Karman models. All the synthesized rational shaping filters use one time constant, automatically adapted to the medium- and long-term components that pilot the other time constants of the shaping filters by a set of parameters practically constant. Some numerical results concerning time series that simulate the non-stationary wind speed with three-dimensional turbulence components based on Kaimal and von Karman models are presented. 相似文献
47.
Survey and laboratory evidence suggests several factors affecting sleep-wake patterns of college students. These factors include social and academic demands, diminution of parental guidance, reduction of total sleep time, delayed bedtime, and increased nap episodes. In this study, we examined the problem of falling asleep in school as a correlate of negative moods in this population (N = 294). A multivariate analysis showed significant main effects of sleepiness on mood states based on the Profile of Mood States. Students who fell asleep in school reported higher negative mood states. Significant interactions were observed among sleepiness and age, sex, race, and duration of sleep. Specifically, younger men reported higher negative moods. No interactions were noted for alcohol and marijuana consumption; however, students who fell asleep in school consumed more alcoholic beverages and smoked more than those who did not. Perhaps falling asleep in school could be used as an index that characterizes students who manifest adaptive or psychological difficulty. 相似文献
48.
A new continuous-flow recycle microwave reactor for homogeneous and heterogeneous chemical reactions
A new continuous-flow recycle microwave reactor suitable for organic synthesis has been developed to handle 0.51 quantities of reagents. The apparatus, which is designed for laboratory use, operates at atmospheric pressure in open- or closed-loop mode. It is fitted with a temperature control system. We describe this novel reactor and illustrate its efficiency with examples of organic syntheses carried out using both homogeneous and heterogeneous reactions. 相似文献
49.
A finite difference scheme for solving the problem of natural transport of heat, mass, momentum and species concentration along vertical porous plates is presented. Several drying related problems are numerically solved, by including a gas-injection boundary condition directly into the governing equations. The effect of variable physical properties is investigated by means of direct comparison against experimental data obtained through holographic interferometry. The relative importance of wall diffusive and convective fluxes is examined. Sherwood and Nusselt numbers can be accurately obtained by means of the proposed techniques. 相似文献
50.