187 research outputs found
Method for Increasing the Efficiency of Automatic Fire Extinguish System at Objects Of Power
No full textOperation of energy facilities requires compliance with all safety standards, and especially fire safety. Emergency situations that arise when operated the power equipment damage not only the objects of the technosphere but also the environment. In recent years, can be noted a trend of quite intensive development of technological bases of technology water mist fire extinguishing. Using the methods of optical panoramic imaging PIV, IPI and the method of high-speed video recording were performed the experimental studies of the characteristics of evaporation of large single water droplets as they pass through the flames of oil and oil products with varying parameters of the processes (the initial size of 2–6 mm, the rate of 2–4 m/s and the temperature of water drops 290–300 K, the temperature of the combustion products 185–2073 K). Was established decisive influence droplet size, velocities at which droplets enter the gaseous medium, the initial water temperature on heating rate and evaporation of droplets in a stream of high-temperature combustion products
Substitution pattern in ruthenium octa-n-butoxyphthalocyanine complexes influence their reactivity in N-H carbene insertions
No full textInternational audienceRuthenium phthalocyanine complexes bearing n-OBu substituents in the peripheral or non-peripheral positions are efficient catalysts for the selective double or single carbene insertion to the amine N–H bonds. This complementary reactivity of two Ru complexes can be used for the synthesis of asymmetric tertiary amines and diamines bearing different substituents and has been demonstrated by two examples of readily available primary amines using different carbene precursors in successive reactions
ТЕХНОЛОГИЯ МОДЕЛИРОВАНИЯ КОММУНИКАТИВНЫХ СИТУАЦИЙ КАК СРЕДСТВО ФОРМИРОВАНИЯ ПРОФЕССИОНАЛЬНОЙ САМООРГАНИЗАЦИИ
No full textIn this paper it is determined that the main way of impro-ving the quality of professional training is the process of foreign language communication as the way of forming personal skills of professional self -organization. In general, a professional self-organization is understood appearring different levels of personal innovations in personal structures of consciousness. We prove that a technology of modeling communicative situations is flexible and adaptive model of forming professional skills of self-organization.В статье отмечается, что основным способом повышения качества профессиональной подготовки является процесс организации иноязычного общения, который способствует формированию умений профессиональной самоорганизации. В общем смысле профессиональная самоорганизация понимается как проявление различных уровней личностно - профессиональных новообразований в личностных структурах сознания. Доказывается, что технология моделирования коммуникативных ситуаций является гибкой и адаптивной моделью формирования умений профессиональной самоорганизации
Experimental Investigation of Droplet Evaporation of Suspension Based on Water with Subsurface Admixtures in a Flame Area
No full textThe influence of typical mixtures (clay, sand, soil, silt) on integral characteristics of droplet evaporation of suspension based on water in high-temperature (about 1100 K) gases was investigated experimentally by the optical methods and high-speed (to 10{5} frames per second) video recording system. The significant intensification of heat up and evaporation of suspension droplets was defined when varying the relative mass fraction of admixtures within the range γ=0−0.1 for a sand, γ=0−0.01 for clay, ground, and silt
Reactivity of Aluminum Carbenoid with Unsaturated Substrates
Get PDFReactivity patterns of the β-diketiminate aluminum(I) complex NacNacAl towards a variety of unsaturated molecules were determined. Reaction of NacNacAl with one equivalent of benzophenone affords η2(C,O) adduct III-2 that undergoes cyclization reactions with benzophenone (III-3), aldimine (III-4), quinoline (III-5), pyridine (III-6), phenyl nitrile (III-7), trimethylsilyl azide (III-8), and a saturated cyclic thiourea (III-9). The latter reacted via unusual C−N cleavage. Analogous η2-coordination products were prepared with p-tolyl benzoate (IV-6), N,N-dimethylbenzamide (IV-9) and (1‐phenylethylidene)aniline (IV-13). Addition of pyridine to such species results in [2+2] cycloaddition products analogous to III-6, except for the case of p‐tolyl benzoate when a migration of the alkoxy group from the ester moiety accompanied by hydrogen transfer from pyridine preserves the aromaticity within the latter. Chemoselective couplings between aliphatic ketones and pyridine were exemplified by reactions with non-enolizable (1R)-(‒) fenchone and enolizable yet sterically encumbered isophorone. The reaction with the CH‐acidic ketone (1R) (+) camphor afforded a hydrido alkoxide (IV-11) as the result of enolization. Whereas the reaction of NacNacAl with (1R)‐(−)‐fenchone in the absence of pyridine led to CH activation in the isopropyl group of the NacNac ligand.
NacNacAl demonstrated diverse reactivity in reactions with N‐heterocycles. 4 Dimethylaminopyridine induces rearrangement of NacNacAl by deprotonation of backbone methyl group of the ligand. C−H activation of the methyl group of 4‐picoline produced a species with a reactive terminal methylene. Reaction of NacNacAl with 3,5 lutidine led to the cleavage of the sp2 C−H bond (4‐position). Another reactivity mode was observed for quinoline, which undergoes 2,2′‐coupling. Finally, a reaction of NacNacAl with phthalazine produced a product of the N−N bond cleavage.
NacNacAl reacted with a series of polycyclic aromatic hydrocarbons via [4+1] cycloaddition. While a reaction with anthracene was irreversible, with the formation of products of activation of the lateral and central rings, reactions with phenanthrene, triphenylene, and fluoranthene were reversible. Heating reaction mixtures at 90 °C yielded dialuminum hydride VI-6. Mechanistic studies showed that the reaction proceeds via dissociation of polycycles with the release of NacNacAl that undergoes further intermolecular transformations. All novel complexes were characterized by spectroscopic methods and X-ray diffraction analysis for most of them
On the "Demon" problem of Youden
No full textWe consider the problem of finding the probability of a sample mean falling between (n - k - 1)th and (n - k)th, 0 [less-than-or-equals, slant] k [less-than-or-equals, slant] n - 1, order statistics in a random sample of size n. Explicit expressions are obtained for uniform and exponential distributions. Under mild regularity assumptions, we also establish the asymptotic normality of the sample proportion above the sample mean when suitably standardized.Order statistics Kiefer-Bahadur's representation Asymptotic normality
Ignition of the Soaring Droplet Sets of Waste-Derived Coal-Water Slurry With Petrochemicals
No full textWe have analyzed the ignition of droplet sets of waste-derived coal-water slurry with petrochemicals for the case of their soaring inside special combustion chamber. The fuel composition consists of filter cake of bituminous coal type G, waste turbine oil, water and plasticizer. Features of the ignition process were emphasized for groups of three soaring droplets in comparison with single droplet ignition. The ignition delay times were registered for particles that were deformed or segregated due to the interaction of initial fuel droplets with walls of the combustion chamber
The 'demon' problem of Youden: Exponential case
No full textWe consider the problem of finding the probability of a sample mean falling above the (n - k)th-order statistic in a random sample of size n. Explicit expressions are obtained for the exponential distribution. Some applications that pertain to testing for outliers and goodness of fit are given.
Influence of the radio signals frequency band on their spatial selection in communication channels
No full textThis article deals with the dependence of the signal-to-noise ratio (S/N) on the frequency band of a radio channel when transmitting three different radio signals over it based on a mathematical model. Signals are transmitted on a single carrier frequency, in one direction and occupy the entire channel frequency band, which varied from 0 to 30 GHz. A threeelement sparse antenna array (SAA) is used for signal transmission. Each signal is emitted by all three SAA elements with certain phase shifts. In the reception area, such a structure of the total field is formed, at which the maxima of all transmitted signals are spatially spaced. This allows each signal to be received on a separate antenna. Studies have shown that the S/N ratio for different signals depends differently on the channel bandwidth. For a signal emitted by all SAA antennas in phase, the S/N ratio is practically independent of the bandwidth and is about 70 dB. For the two remaining phased signals the S/N ratio varies equally over the entire range of the channel frequency band values and is characterized by a sharp drop from 62 to 8 dB
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