201 research outputs found

    Estimation of the adsorption capacity of oil-bearing rocks: A method and its prospects

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    The adsorption capacity of natural cores of the oil-bearing rocks has been studied by using vapor-phase gas chromatography (statistical method). The thermodynamic parameters of sorption of reservoir rocks (dried, after extraction of oil) are determined by the mineralogical composition of cement in the sandstone cores. The presence of water decreases the adsorption capacity. However, if the rock contains kaolinite, the sorption of hydrocarbons increased 10-fold in the presence of water. The adsorption capacity of the oil-bearing rock is related to the combined properties of organo-mineral complexes. © 2002 Published by Elsevier Science B.V

    Mordovo-Karmalskoye Field: The Bitumen Composition in Productive Strata after Passing of the Combustion Front in Well

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    The specific features of the composition of both natural bitumens of the Mordovo-Karmalskoye field and products of the bitumen thermal transformation in strata after passing of the combustion front in a well are studied. The composition of organic matter and its bitumen components left in reservoir after passing of the combustion front and the parameters of bitumen which underwent no artificial impact are compared. The combustion is found to cause the deep transformations in the bitumen composition and the differentiation of bitumen properties through a cross section. The rather light bitumen (density is equal to 0,94 g/cm3) is in the low concentration in the roof part of stratum. A content of paraffin-naphtene hydrocarbons, particularly nalkanes, increases in the hydrocarbon part of bitumen. Accordingly to the group and hydrocarbon compositions, the elemental composition is altered, the hydrogen content increases and the sulphur content decreases. Contrarily, the bitumen in the combustion interval is heavier (1,013 g/cm3). A quality of the bitumen is minimal there. The interlayers having an enhanced content of the insoluble organic compounds are found. The high content of asphaltenes causes the low hydrogen content and the high carbon content in the bitumen composition. All these parameters are abnormal if to compare with the ordinary, non-transformed bitumens of the Mordovo-Karmalskoye field. In the lower part of cross section underwent no combustion, the content and composition of bitumen become ordinary for the productive thickness. At the same time, the lower oil content and the higher content of asphaltenes and sulphur in bitumens are an evidence to the displacement of light to the productive wells hydrocarbons simultaneously to passing of the combustion front. That confirms the earlier observed fact that the oil is produced at the part of reservoir which underwent no in situ combustion. In addition to the alterations in the organic matter composition and content, the bitumen-bearing rocks are also transformed, particularly a ratio between iron(II), iron(III) compounds and pyrite is changed. The revealed factors which effect the quality of recovered bitumens and the alterations in the mineralogy make possible to control the temperature regime and passing of the combustion front

    AGILE detection of extreme gamma-ray activity from the blazar PKS 1510-089 during March 2009. Multifrequency analysis

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    We report on the extreme gamma-ray activity from the FSRQ PKS 1510-089 observed by AGILE in March 2009. In the same period a radio-to-optical monitoring of the source was provided by the GASP-WEBT and REM. Moreover, several Swift ToO observations were triggered, adding important information on the source behaviour from optical/UV to hard X-rays. We paid particular attention to the calibration of the Swift/UVOT data to make it suitable to the blazars spectra. Simultaneous observations from radio to gamma rays allowed us to study in detail the correlation among the emission variability at different frequencies and to investigate the mechanisms at work. In the period 9-30 March 2009, AGILE detected an average gamma-ray flux of (311+/-21)x10^-8 ph cm^-2 s^-1 for E>100 MeV, and a peak level of (702+/-131)x10^-8 ph cm^-2 s^-1 on daily integration. The gamma-ray activity occurred during a period of increasing activity from near-IR to UV, with a flaring episode detected on 26-27 March 2009, suggesting that a single mechanism is responsible for the flux enhancement observed from near-IR to UV. By contrast, Swift/XRT observations seem to show no clear correlation of the X-ray fluxes with the optical and gamma-ray ones. However, the X-ray observations show a harder photon index (1.3-1.6) with respect to most FSRQs and a hint of harder-when-brighter behaviour, indicating the possible presence of a second emission component at soft X-ray energies. Moreover, the broad band spectrum from radio-to-UV confirmed the evidence of thermal features in the optical/UV spectrum of PKS 1510-089 also during high gamma-ray state. On the other hand, during 25-26 March 2009 a flat spectrum in the optical/UV energy band was observed, suggesting an important contribution of the synchrotron emission in this part of the spectrum during the brightest gamma-ray flare, therefore a significant shift of the synchrotron peak.Comment: 13 pages, 7 figures, 3 tables. Accepted for publication in Astronomy and Astrophysic

    Electron acceleration and heating in collisionless magnetic reconnection

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    We discuss electron acceleration and heating during collisionless magnetic reconnection by using the results of implicit kinetic simulations of Harris current sheets. We consider and compare electron dynamics in plasmas with different \beta values and perform simulations up to the physical mass ratio. We analyze the typical trajectory of electrons passing through the reconnection region, we study the electron velocity, focusing on the out-of-plane velocity, and we discuss the electron heating along the in-plane and out-of-plane directions

    Accreting Millisecond X-Ray Pulsars

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    Accreting Millisecond X-Ray Pulsars (AMXPs) are astrophysical laboratories without parallel in the study of extreme physics. In this chapter we review the past fifteen years of discoveries in the field. We summarize the observations of the fifteen known AMXPs, with a particular emphasis on the multi-wavelength observations that have been carried out since the discovery of the first AMXP in 1998. We review accretion torque theory, the pulse formation process, and how AMXP observations have changed our view on the interaction of plasma and magnetic fields in strong gravity. We also explain how the AMXPs have deepened our understanding of the thermonuclear burst process, in particular the phenomenon of burst oscillations. We conclude with a discussion of the open problems that remain to be addressed in the future.Comment: Review to appear in "Timing neutron stars: pulsations, oscillations and explosions", T. Belloni, M. Mendez, C.M. Zhang Eds., ASSL, Springer; [revision with literature updated, several typos removed, 1 new AMXP added

    Складові компоненти мовної особистості в контексті міжкультурної комунікації

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    Стаття присвячена аналізу складових компонентів мовної особистості в контексті міжкультурної комунікації, їх взаємодії та функціонуванню з точки зору прагматичної спрямованості мовленнєвого впливу. Детально розглядаються три рівні структури мовної особистості (структурно-мовний, лінгвокогнітивний ті мотиваційний) із визначенням специфіки їхніх складових компонентів.Статья посвящена анализу составляющих компонентов языковой личности в контексте межкультурной коммуникаций, их взаимодействию и функционированию с точки зрения прагматической направленности речевого воздействия. Детально рассматриваются три уровня структуры языковой личности (структурно-языковой, лингвокогнитивный и мотивационный) с последующим определением специфики их составляющих компонентов.The article is dedicated to the linguistic personality constituent components' analysis in terms of cross-cultural communication, their interaction and functioning with the speech influence pragmatic orientation taken into consideration. The three levels of the linguistic personality (that is, structural linguistic, lingo cognitive and motivation ones) are under analysis with the following their constituent components specificity determinatio

    Neuropeptidomics of the Supraoptic Rat Nucleus

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    The mammalian supraoptic nucleus (SON) is a neuroendocrine center in the brain regulating a variety of physiological functions. Within the SON, peptidergic magnocellular neurons that project to the neurohypophysis (posterior pituitary) are involved in controlling osmotic balance, lactation, and parturition, partly through secretion of signaling peptides such as oxytocin and vasopressin into the blood. An improved understanding of SON activity and function requires identification and characteriza-tion of the peptides used by the SON. Here, small-volume sample preparation approaches are optimized for neuropeptidomic studies of isolated SON samples ranging from entire nuclei down to single magnocellular neurons. Unlike most previous mammalian peptidome studies, tissues are not im-mediately heated or microwaved. SON samples are obtained from ex vivo brain slice preparations via tissue punch and the samples processed through sequential steps of peptide extraction. Analyses of the samples via liquid chromatography mass spectrometry and tandem mass spectrometry result in the identification of 85 peptides, including 20 unique peptides from known prohormones. As the sample size is further reduced, the depth of peptide coverage decreases; however, even from individually isolated magnocellular neuroendocrine cells, vasopressin and several other peptides are detected

    Role of Caustic Addition in Bitumen-Clay Interactions

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    Coating of bitumen by clays, known as slime coating, is detrimental to bitumen recovery from oil sands using the warm slurry extn. process. Sodium hydroxide (caustic) is added to the extn. process to balance many competing processing challenges, which include undesirable slime coating. The current research aims at understanding the role of caustic addn. in controlling interactions of bitumen with various types of model clays. The interaction potential was studied by quartz crystal microbalance with dissipation monitoring (QCM-D). After confirming the slime coating potential of montmorillonite clays on bitumen in the presence of calcium ions, the interaction of kaolinite and illite with bitumen was studied. To represent more closely the industrial applications, tailings water from bitumen extn. tests at different caustic dosage was used. At caustic dosage up to 0.5 wt % oil sands ore, a negligible coating of kaolinite on the bitumen was detd. However, at a lower level of caustic addn., illite was shown to attach to the bitumen, with the interaction potential decreasing with increasing caustic dosage. Increasing concn. of humic acids as a result of increasing caustic dosage was identified to limit the interaction potential of illite with bitumen. This fundamental study clearly shows that the crit. role of caustics in modulating interactions of clays with bitumen depends upon the type of clays. Thus, clay type was identified as a key operational variable

    Опыт применения противовирусной терапии врожденной генерализованной цитомегаловирусной инфекции

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    The article presents the results of observation and treatment with ganciclovir and oral valganciclovir form of a premature infant with congenital generalized symptomatic cytomegalovirus infection (CMVI) involving pathology of CNS, cholangitis, spontaneous pathologic fracture of femoral bone. When using ganciclovir and valganciclovir demonstrated gradual normalization of clinical and hematological parameters. In the course of treatment with ganciclovir and valganciclovir was not revealed any adverse reactions. While maintaining the CMV DNA in the blood, the duration of specific therapy, according to international recommendations, should be not less than 6 months. The decision to use a specific therapy should be made on the basis of the medical consultation, the conclusions of the medical commission and informed consent of the parents.В статье представлены результаты наблюдения и лечения ганцикловиром и пероральной формой валганцикловира недоношенного ребенка с врожденной манифестной генерализованной цитомегаловирусной инфекцией (ВЦМВИ), протекающей с поражением ЦНС, холангитом, спонтанным патологическим переломом бедренной кости. При использовании ганцикловира и валганцикловира продемонстрирована постепенная нормализация клинических и гематологических показателей. В процессе лечения ганцикловиром и валганцикловиром не было выявлено каких-либо побочных реакций. Основным методом мониторинга специфического лечения должно быть определение вирусной нагрузки (количество ДНК ЦМВ в лейкоцитах крови). При сохранении ДНК ЦМВ в крови, длительность специфической терапии, согласно международным рекомендациям, должна быть не меньше 6 месяцев. Решение об использовании специфической терапии должно приниматься на основании врачебного консилиума, заключения медицинской комиссии и получения информированного согласия родителей
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