240 research outputs found
Evaluation method of influence of catalyst precursors on initiation of in-situ combustion and it's dynamics
Copyright 2017, Society of Petroleum Engineers. The growing demand for energy requires alternative technologies for the development of new deposits with tar sands and heavy oil, as well as the rehabilitation of depleted, abandoned deposits. Combining all the advantages of thermal methods, the method of in-situ combustion in the presence of catalyst precursors caused interest in petroleum industry due to the possibility of upgrading or primary refining of heavy oils directly in the reservoir. This article describes an experimental method for studying the effect of catalyst precursors on initiation of in-situ combustion of heavy oils. Thermograms in air atmosphere (combustion curves) for oil-saturated sandstones from Permian deposits in the presence of different precursors were obtained. As a precursor, resinates of copper, cobalt, iron and nickel were used. The possibility of evaluation the catalyst effect on the initiation of in-situ combustion was shown
Non-perturbative vacuum-polarization effects in proton-laser collisions
In the collision of a high-energy proton beam and a strong laser field,
merging of the laser photons can occur due to the polarization of vacuum. The
probability of photon merging is calculated by accounting exactly for the laser
field and presents a highly non-perturbative dependence on the laser intensity
and frequency. It is shown that the non-perturbative vacuum-polarization
effects can be experimentally measured by combining the next-generation of
table-top petawatt lasers with presently available proton accelerators.Comment: 5 pages, 2 figure
Enthalpy of cooperative hydrogen bonding in complexes of tertiary amines with aliphatic alcohols: Calorimetric study
The work is devoted to the investigation of thermodynamics of specific interaction of the tertiary aliphatic and aromatic amines with associated solvents as which aliphatic alcohols were taken. Solution enthalpies of aliphatic alcohols in amines (tri-n-propylamine, 2-methylpyridine, 3-methylpyridine, N-methylimidazole) as well as amines in alcohols were measured at infinite dilution. The enthalpies of specific interaction (H-bonding) in systems studied were determined based on experimental data. The enthalpies of specific interaction of amines in aliphatic alcohols significantly lower than the enthalpies of hydrogen bonding in complexes amine-alcohol of 1:1 composition determined in base media due to the reorganization of aliphatic alcohols as solvents. The determination of solvent reorganization contribution makes possible to define the hydrogen bonding enthalpies of amines with clusters of alcohols. Obtained enthalpies of hydrogen bonding in multi-particle complexes are sensitive to the influence of cooperative effect. It was shown, that hydrogen bond cooperativity factors in multi-particle complexes of alcohols with amines are approximately equal for all alcohols when pyridines and N-methylimidazole as solutes are used. At the same time, H-bonding cooperativity factors in complexes of trialkylamines with associative species of alcohols decrease with increasing of alkyl radical length in alcohol and amine molecules. This work shows that the thermodynamic functions of specific interaction of solutes with associated solvents cannot be described using the H-bond parameters for the complexes of 1:1 composition. © 2011 Elsevier Ltd. All rights reserved
Laser photon merging in proton-laser collisions
The quantum electrodynamical vacuum polarization effects arising in the
collision of a high-energy proton beam and a strong, linearly polarized laser
field are investigated. The probability that laser photons merge into one
photon by interacting with the proton`s electromagnetic field is calculated
taking into account the laser field exactly. Asymptotics of the probability are
then derived according to different experimental setups suitable for detecting
perturbative and nonperturbative vacuum polarization effects. The
experimentally most feasible setup involves the use of a strong optical laser
field. It is shown that in this case measurements of the polarization of the
outgoing photon and and of its angular distribution provide promising tools to
detect these effects for the first time.Comment: 38 pages, 9 figure
Vaporization enthalpies of a series of the fluoro- and chloro-substituted methylbenzenes
Vapor pressures of fluorobenzene, chlorobenzene, 2-chloro-, 3-chloro-, and 4-chloro-methylbenzenes, 2-chloro-1,3-dimethylbenzene, 2,6-dichloro-1-methylbenzene were measured by the transpiration method. Molar standard enthalpies of vaporization at the reference temperature were calculated from temperature dependences of vapor pressures. Available literature data on halogenobenzenes were collected and evaluated by using correlation gas-chromatographic method. Simple group-additivity procedure was developed for estimation vaporization enthalpies of mono- and di-halogen-substituted benzenes. © 2014
Thermochemistry of dihalogen-substituted benzenes: Data evaluation using experimental and quantum chemical methods
© 2014 American Chemical Society. Temperature dependence of vapor pressures for 12 dihalogen-substituted benzenes (halogen = F, Cl, Br, I) was studied by the transpiration method, and molar vaporization or sublimation enthalpies were derived. These data together with results available in the literature were collected and checked for internal consistency using structure-property correlations. Gas-phase enthalpies of formation of dihalogen-substituted benzenes were calculated by using quantum-chemical methods. Evaluated vaporization enthalpies in combination with gas-phase enthalpies of formation were used for estimation liquid-phase enthalpies of formation of dihalogen-substituted benzenes. Pairwise interactions of halogens on the benzene ring were derived and used for development of simple group additivity procedures for estimation of vaporization enthalpies, gas-phase, and liquid-phase enthalpies of formation of dihalogen-substituted benzenes
Benchmark thermochemistry of methylbenzonitriles: Experimental and theoretical study
© 2015 Elsevier Ltd. All rights reserved. The gas-phase enthalpies of formation of 2-, 3-, and 4-methylbenzonitrile at T = 298.15 K were studied by combustion calorimetry, and their vaporization enthalpies were determined using the transpiration method. The composite ab initio methods W1-F12 and G4 were used to calculate the gas-phase enthalpies of formation for these three methylbenzonitriles. These theoretical values were found to be in excellent agreement with the corresponding experimental data. The analysis of these data revealed that the interaction between cyano and methyl groups is slightly stabilizing. Using the experimental data a set of group-additivity terms, which allows to estimate thermochemical properties for methyl and cyano substituted benzenes, was proposed. These terms, together with theoretical data, were subsequently used to reassess the thermochemical properties of 2,6-dimethylbenzonitrile and 2,4,6-trimethylbenzonitrile
Vaporization enthalpies of a series of the halogen-substituted fluorobenzenes
© 2014 Elsevier B.V. Vapor pressures of 2-, 3-, and 4-halogen-substituted fluorobenzenes (halogen. =. Cl, Br, and I) were measured by the transpiration method. Molar standard enthalpies of vaporization were calculated from temperature dependences of vapor pressures. New enthalpies of vaporization at 298. K and those available from literature were tested for consistency by correlation gas-chromatography and evaluated by group-additivity method. Contributions to vaporization due to mutual interactions of halogens on the benzene ring were derived and recommended for prediction vaporization enthalpies of halogen-substituted aromatics
Regulation of caspase-3 processing by cIAP2 controls the switch between pro-inflammatory activation and cell death in microglia.
Cell Death and Disease is an open-access journal published by Nature Publishing Group. This work is licensed under a Creative Commons Attribution 4.0 International Licence. The images or other third party material in this article are included in the article’s Creative Commons licence, unless indicated otherwise in the credit line; if the material is not included under the Creative Commons licence, users will need to obtain permission from the licence holder to reproduce the material.The activation of microglia, resident immune cells of the central nervous system, and inflammation-mediated neurotoxicity are typical features of neurodegenerative diseases, for example, Alzheimer's and Parkinson's diseases. An unexpected role of caspase-3, commonly known to have executioner role for apoptosis, was uncovered in the microglia activation process. A central question emerging from this finding is what prevents caspase-3 during the microglia activation from killing those cells? Caspase-3 activation occurs as a two-step process, where the zymogen is first cleaved by upstream caspases, such as caspase-8, to form intermediate, yet still active, p19/p12 complex; thereafter, autocatalytic processing generates the fully mature p17/p12 form of the enzyme. Here, we show that the induction of cellular inhibitor of apoptosis protein 2 (cIAP2) expression upon microglia activation prevents the conversion of caspase-3 p19 subunit to p17 subunit and is responsible for restraining caspase-3 in terms of activity and subcellular localization. We demonstrate that counteracting the repressive effect of cIAP2 on caspase-3 activation, using small interfering RNA targeting cIAP2 or a SMAC mimetic such as the BV6 compound, reduced the pro-inflammatory activation of microglia cells and promoted their death. We propose that the different caspase-3 functions in microglia, and potentially other cell types, reside in the active caspase-3 complexes formed. These results also could indicate cIAP2 as a possible therapeutic target to modulate microglia pro-inflammatory activation and associated neurotoxicity observed in neurodegenerative disorders
Thomson scattering diagnostics at the Globus M2 tokamak
The paper is devoted to the Thomson scattering (TS) diagnostics recently
developed for the Globus-M2 spherical tokamak and prototyping the ITER divertor
TS diagnostics. The distinctive features of the system are the use of
spectrometers, acquisition system and lasers that meet the base requirements
for ITER TS diagnostics. The paper describes the diagnostic system that allows
precise measurements of TS signals, as well as the results of the first
measurements of electron temperature and density in both central region of the
plasma column and scrape-off layer. The system provides measurements of
electron temperature in the range of 5 eV to 5 keV and density
in the range of . The use of
two ITER-grade probing lasers of different wavelengths (Nd:YAG 1064.5 nm and
Nd:YLF 1047.3 nm) allows reliable measurement of in multi-colour mode,
i.e., assuming that spectral calibration is unknown
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