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S. B. Dorofeev M. S. Kuznetsov V. I. Alekseev A. A. Efimenko W. Breitung 《Journal of Loss Prevention in the Process Industries》2001,14(6):583-589
Results of experiments and data analysis on turbulent flame propagation in obstructed channels are presented. The data cover a wide range of mixtures: H2/air, H2/air/steam (from lean to rich) at normal and elevated initial temperatures (from 298 to 650 K) and pressures (from 1 to 3 bar); and stoichiometric H2/O2 mixtures diluted with N2, Ar, He and CO2 at normal initial conditions. The dataset chosen also covers a wide range of scales exceeding two orders of magnitude. It is shown that basic flame parameters, such as mixture expansion ratio σ, Zeldovich number β and Lewis number Le, can be used to estimate a priori a potential for effective flame acceleration for a given mixture. Critical conditions for effective flame acceleration are suggested in the form of correlations of critical expansion ratio σ* versus dimensionless effective activation energy. On this basis, limits for effective flame acceleration for hydrogen combustibles can be estimated. Uncertainties in determination of critical σ* values are discussed. 相似文献
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Effect of soil acidification induced by a tea plantation on chemical and mineralogical properties of Alfisols in eastern China 总被引:3,自引:0,他引:3
T. Alekseeva A. Alekseev Ren-Kou Xu An-Zhen Zhao P. Kalinin 《Environmental geochemistry and health》2011,33(2):137-148
The effect of a tea plantation on soil basic properties, chemical and mineralogical compositions, and magnetic properties
of Alfisols from eastern China was studied. Under the tea plantation, acidification took place within a soil depth of 70 cm,
with the maximum difference in pH in the upper 17 cm (ΔpH = 2.80). Both the tea plantation and unused soil profiles were predominated
by free Fe and Al oxides, i.e. citrate/bicarbonate/dithionite extractable Fe (Fed) and Al (Ald). Tea plantation soil was characterized by higher Ald and Fed and lower Fe oxalate, Fe2O3 and Al2O3; CaO was depleted, whereas SiO2 accumulated. Acidification induced by the tea plantation led to destruction of vermiculite followed by dissolution of the
hydroxy-Al interlayers within its structure. The data clearly demonstrated that significant soil weathering occurred with
acidification caused by tea cultivation. This acidification also resulted in decreased content of ferrimagnetic minerals due
to the dissolution of minerals and movement of Fe in the profile. 相似文献
3.
Vyacheslav Viktorovich Alekseev 《Ecological modelling》1982,17(2):107-112
An equation is developed for the dependence of the maximum number of species in an ecosystem on temperature. A comparison with observations for marine ecosystems in different latitudes suggests an excellent agreement of theory with observations for the temperature interval 0–30°C. 相似文献
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Pascal Godefroit Lina Golovneva Sergei Shchepetov Géraldine Garcia Pavel Alekseev 《Die Naturwissenschaften》2009,96(4):495-501
A latest Cretaceous (68 to 65 million years ago) vertebrate microfossil assemblage discovered at Kakanaut in northeastern
Russia reveals that dinosaurs were still highly diversified in Arctic regions just before the Cretaceous–Tertiary mass extinction
event. Dinosaur eggshell fragments, belonging to hadrosaurids and non-avian theropods, indicate that at least several latest
Cretaceous dinosaur taxa could reproduce in polar region and were probably year-round residents of high latitudes. Palaeobotanical
data suggest that these polar dinosaurs lived in a temperate climate (mean annual temperature about 10°C), but the climate
was apparently too cold for amphibians and ectothermic reptiles. The high diversity of Late Maastrichtian dinosaurs in high
latitudes, where ectotherms are absent, strongly questions hypotheses according to which dinosaur extinction was a result
of temperature decline, caused or not by the Chicxulub impact. 相似文献
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Mymrin Vsevolod Aibuldinov Elaman K. Avanci Monica A. Alekseev Kirill Argenda Marco A. Carvalho Karina Q. Erbs Alexandre Catai Rodrigo E. 《Journal of Material Cycles and Waste Management》2021,23(2):591-603
Journal of Material Cycles and Waste Management - The article presents data from new compositions of construction materials developed from three types of Kazakhstan enterprises’ industrial... 相似文献
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The chaotic dynamics observed in a number of natural and artificial ecosystems is assumed to be caused by an intrinsic stochasticity of the modelling dynamical systems involved. The paper considers the transition to stochasticity and its peculiarities in the dynamical system simulating most typical ecological interactions. 相似文献
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Mymrin Vsevolod Alekseev Kirill Klitzke Walderson de Evaniki Daniela Pedroso Cleber L. Passig Fernando H. Carvalho Karina Q. Haminiuk Charles W. I. Catai Rodrigo E. 《Journal of Material Cycles and Waste Management》2023,25(3):1549-1559
Journal of Material Cycles and Waste Management - This paper reports the development and characterization of new ceramics from hazardous bauxite red mud (50... 相似文献
8.
V. I. Alekseev M. S. Kuznetsov Yu. G. Yankin S. B. Dorofeev 《Journal of Loss Prevention in the Process Industries》2001,14(6):12381-596
Results of experiments on critical conditions for flame acceleration and the deflagration-to-detonation transition in tubes with transverse venting are presented. Tests were made with hydrogen mixtures in two tubes (inner diameter of 46 and 92 mm) with obstacles. Ratios of vent area to total tube area were 0.2 and 0.4. Venting was shown to influence flame acceleration significantly. The greater the vent ratio, the more reactive the mixture necessary for development of fast flames. Critical conditions for flame acceleration in tubes with venting, expressed through a critical mixture expansion ratio σcr, were found to be σcr/σ01+2, where σ0 is the critical value for a closed tube. Critical conditions for detonation onset in a vented tube were found to be very close to those in a closed tube with similar configuration of obstacles. 相似文献
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