Dispersed methane flux to the water column from natural gas bubble streams at the Black Sea shelf

Gas bubble streams are detected in the water column by the presence of strong, flare shaped backscatter signals recorded during hydroacoustic single beam echosounder surveys (flares). Some of these flares even reach the sea surface. In motion bubbles get into an evolutionary process caused by a variety of effects, including gaseous exchange with surrounding water. Simplistically, kinetics of such a gas exchange can be described by the Fick’s law; the direction of the transfer of any given gas through the bubble depends on partial pressure of respective the gas in bubble, Henry’s law constants and the concentration of dissolved gas in the water. In general, methane gradually dissolves during the lifetime of a bubble, while other gases enter the bubble. Consequently, bubbles cause a vertical transfer of methane from the sea bottom to upper water layers and can be considered as sources of dispersed methane flux to the water column. In present work an attempt is made to trace the methane gas phase exhaustion in flares trough the water column at the Black Sea shelf.Our approach is based upon acoustic observations and measurements carried out in 2003 and 2004 with the scientific echosounder EK-500 onboard RV Vodianitskiy as part of the EU funded project CRIMEA. For the estimation of bubble size distributions our data from direct measurements of acoustic cross-section of single bubbles were used. Data for the relation between rising speed and shrinking rate vs. bubble size were obtained by tracking of single bubbles. Modelling was used to evaluate features of the gas transfer process induced by rising bubbles. Having initial bubble size, gas composition and water depth as starting conditions the model produces series of time based values of bubble size, gas composition, rising depth and rising speed. Acoustic observations were utilized to verify the chosen model parameters.For seeps detected at 90 - 95 m water depth hydroacoustically measured bubble sizes ranged from 1.3 to 11.3 mm in diameter. This bubble size range was confirmed by visual observations during video and submersible inspections.We assumed a gas content of 99% methane and small amounts of nitrogen and oxygen as initial gas composition according to geochemical analyses of gas bubbles sampled by submersible just above the sea floor. To determine the entire free methane flux from the sea floor into the water column and maybe into the atmosphere we run our model for several bubble sizes classes. Then simulation data were summed up with weighting coefficients according to the respective amount of bubbles per class. As a result, vertical profiles of molar content (mkmol) and methane flux (mkmol/s m) per average statistic bubble vs. depth were obtained. To get methane flux from the whole seepage simple multiplication is required by average statistic initial number of bubbles above the bottom per unit height. Depending on the spatial extension of the seep area, point or volume backscattering methods were used to quantify the bubble amount. Of great importance for both methods is the averaging of a high amount of data in space and time. We detected an average of 400 bubbles at high intensity seep sites within a water volume of 1m thickness above the bottom. The hydroacoustically determined amount of bubbles is again in very good agreement with direct visual observations. With an average initial rising speed of 0.25 m/s, 400 bubbles escaping from the sea floor cause a methane flux of 3.45 mmol/s using average bubble methane content of 34.5 mkmol (400 x 0.25 x 34.5 = 3.45 mmol/s). As final methane content of average bubble at the sea surface is 6.5 mkmol, only 6.5/34.5*100 = 18.8 % of methane can reach the atmosphere due to the methane flux into the water column on the way up to the sea surface

Microbial carbonate build-ups at methane seeps near the upper boundary of the gas-hydrate stability zone in the Black Sea: results of EU project CRIMEA

Extensive dredging carried out in May-June 2004 in the deeper parts of the Dnepr paleo-delta area (NW Black Sea) yielded for the first time chimney-shaped carbonate microbial build-ups, which occur at methane seeps close to upper boundary of the gas-hydrate stability zone (~ 700 m). Carbonate samples taken with a benthic trawl represent fragments of the uppermost, middle and lowest parts of the build-up, which are similar to those found previously at the shallower and deeper methane seeps in the Black Sea. At the same time, the holed, plate-like carbonates in the lowest parts of the build-up provide first indications that gas channels are formed during the earliest growth phase of these microbial structures. Stable carbon isotope analyses of the carbonates from the uppermost fragments gave the d13C values ranging from -33.7 to -36.6 pro mil, while the d13C values of the lowermost fragments are significantly lighter, varying between -42.0 and -44.6 pro mil. Both these types of carbonates indicate that a major portion of the carbonate carbon originates from bacterial oxidation of the seeping methane. Oxygen isotopic values also show differences between the more irregular and porous samples from the uppermost part of the build-up, which are composed of a mixture of aragonite and Mg-calcite (d18O = 0.7 to 0.94 pro mil, and the only Mg-calcite cemented thin slabs of lowermost carbonates (d18O = 1.35 to 1.57 pro mil. The difference in d13C/d18O ratio found in the upper and lower parts of the build-up may reflect the changing of the water temperature and salinity during the chimney growth

Seismic and hydro-acoustic evidence for subsurface controls of methane seepage in the Dnepr paleo-delta, Black Sea

The Dnepr paleo-delta in the NW Black Sea is characterized by an abundant presence of methane gas seeps. The presence of these seeps was first registered by Polikarpov et al. in 1989. During the CRIMEA 2003 expedition 1062 new plumes were detected using a SIMRAD EK 500 echosounder. All newly found plumes are located on the transition zone of the continental shelf and continental slope in water depths between 70 and 725 meters. A further exploration of the area included the collection of hydro-acoustic and geophysical datasets. For this presentation we have used these new data to get a better insight in the relation between the presence of gas seeps, seafloor morphology and subsurface structures.From the integration of the new datasets (multibeam bathymetric map, side-scan sonar mosaic, seep locations and several sparker, GI-gun and sub-bottom profiles) we could make some interesting observations:seeps are often located at crests of sediment ridges and at edges of canyons;seeps are located in areas characterised by high sea-floor backscatter values;the depth limit for the presence of seeps (725 m) almost coincides with the stability boundary of pure methane hydrate;there is a clear correlation between the depth of gas fronts within the sediments and the presence of seeps at the seafloor.These observations and the apparent absence of major faults on our seismic data suggest that the subsurface controls on methane seepage in our study area are mainly stratigraphic/sedimentary in nature.Whether the presence of seeps at the crest lines of the sediment ridges is due to the presence of more resistant coarse sediments (i.e. location of seeps is controlled by morphology) or whether these crest lines stand out due to enhanced methane-derived carbonate cementation (i.e. the morphology is controlled by the location of the seeps) is still unclear. The exact cause of the high backscatter values in the seep areas (i.e. higher degree of cementation, presence of free-gas bubbles, slightly coarser sediment due to blow-out of the finer fraction by the gas escape) is at present still unclear and awaits further ground-truthing

Трансформация правового регулирования налоговых отношений в условиях цифровой экономики

The subject. The modern world is constantly changing, which makes it necessary to update the means and methods of legal regulation of public relations. Moreover, these relations themselves are changing, new areas of public relations are emerging, for which it is necessary to create a legal framework. The sphere of financial and legal regulation is no exception. The most important issue, which has been on the agenda of the international community for several years, is the development of the digital economy. The legal realities of digitalization largely determine what place the Russian economy will occupy in the emerging global digital market. It is necessary to develop a comprehensive legal concept that allows ensuring compliance with the fiscal interests of the state in the context of digital transformation. In this regard, the transformation of tax relations and their legal regulation is particularly important.Purpose of the study. The article is devoted to the transformation of the legal regulation of tax relations in the digital economy. In order for Russian financial and legal regulation to contribute to an effective response to the challenges posed by digitalization, it is necessary to develop a comprehensive legal concept that allows ensuring compliance with the fiscal interests of the state in the context of digital transformation. In this regard, the transformation of tax relations and their legal regulation is of particular importance.Methodology. The research was carried out with the application of the formally legal interpretation of legal acts as well as the comparative analysis of Russian and European legal literature. Structural and systemic methods are also the basis of the research. The main results. The necessity to develop legal solutions in the field of taxation of the digital economy is determined by the focus on legal support for the stability of financial and legal regulation and the principle of certainty of taxation. In these circumstances, it is important to implement the control function of financial law. The need to ensure compliance with the fiscal interests of the state, both at present and in the long term, requires the transformation of essential approaches to the legal regulation of the system of taxes and fees, the principles and elements of taxation, tax administration and tax control. In this regard, it is proposed to provide for special rules for calculating and paying income tax on foreign digital companies and, in parallel, to expand tax incentives for Russian companies.Сonclusions. The authors come to the conclusion that the actual scientific task is to develop a methodological position on the directions of reforming the national tax legislation and the international tax doctrine of the Russian Federation in the context of the digital transformation of public relations. According to the results of the study, it is concluded that it is necessary to ensure compliance with the fiscal interests of the state. This requires the transformation of essential approaches to the legal regulation of tax relations, both in the context of determining the appropriate legal forms for regulating the tax base levied in Russia in the context of the emerging digital economy, and for influencing international tax policy in order to use all the advantages provided by international tax cooperation and neutralize the threats caused by international tax competition.Рассматривается трансформация правового регулирования налоговых отношений в условиях цифровой экономики. Актуальной научной задачей объявляется выработка методологической позиции относительно направлений реформирования национального налогового законодательства и международной налоговой доктрины Российской Федерации в условиях цифровой трансформации общественных отношений. По итогам исследования делается вывод о необходимости обеспечения соблюдения фискальных интересов государства, что требует трансформации сущностных подходов к правовому регулированию налоговых отношений как в контексте определения надлежащих правовых форм для регламентации налоговой базы, облагаемой в России, в условиях формирующегося цифрового уклада экономики, так и для воздействия на международную налоговую политику с целью использования всех преимуществ, предоставляемых международной налоговой кооперацией, и нейтрализации угроз, вызываемых международной налоговой конкуренцией. В этой связи предлагается предусмотреть специальные правила исчисления и уплаты налога на прибыль иностранных цифровых компаний и параллельно расширять меры налогового стимулирования российских компаний

Aluminum “Core-shell” microparticles with an oxide shell - fillers of spatially strengthened composites, facilitating material digitization

The transformation of aluminum “Core-shell” microparticles formed by low-temperature oxidation with water during their heating in a controlled atmosphere has been studied. Spherical particles with an oxide shell, convenient for mathematical modeling of the structure and properties of the developed composites, are planned to be used as fillers for metal and polymer oxide composites, as well as for 3D printing

Мультипараметрическая магнитно-резонансная томография в диагностике энцефалита, вызванного герпесвирусами, у детей

Introduction. This study is determined with the high prevalence of encephalitis in children, as well as the severe course and the possible disability. Herpes encephalitis occurs in almost half of cases of viral encephalitis in children. It is known that changes on the brain magnetic resonance imaging (MRI) in the acute stage of the disease are detected more often than on brain computed tomography (CT), but the clarification of this brain MRI changes is needed.Objectives of the study. To assess the features of brain multiparametric MRI changes in herpes encephalitis in children.Materials and methods. Two groups of children were examined, the first group included 25 children aged 6,0±4,8 years with laboratory-confirmed acute EH, the second group (control) — 23 children without signs of central nervous system damage at the comparable gender and age. Structural changes were assessed using MRI of the brain in T1-WI, T2-WI, Flair, T1-WI modes post contrast, DWI, DTI and MR spectroscopy.Results. In 40% of cases revealed panencephalitis, 36% — leukoencephalitis, 24% — polioencephalitis. Most often, the process involved the cerebral hemispheres — 72%, the brain stem — 44%, the thalamus — 40% and basal nuclei — 36%. In 52% of cases changes in DWI were found, in 20% of cases the lesions accumulated contrast agent. There was a statistically significant decrease of FA both in the focus and in the intact area in children with EH compared with the control group.Conclusion. The application of multiparametric MRI using DWI, DTI, and MR spectroscopy methods are statistically significant for the detection and assessment of focal brain lesions in children with herpes encephalitis.Введение. Относительно высокая распространенность энцефалитов в детской популяции, а также тяжелое течение и вероятность инвалидизации обусловливают актуальность изучения данной темы. До половины случаев вирусных энцефалитов у детей составляют энцефалиты герпесвирусной этиологии. Известно, что в раннем периоде заболевания изменения на магнитно-резонансной томографии (МРТ) головного мозга регистрируются чаще, чем на компьютерной томографии (КТ) головного мозга, однако значимость выявляемых в остром периоде герпетического энцефалита МРТ изменений требует уточнения.Цели и задачи. Оценить особенности изменений мультипараметрической МРТ головного мозга при герпетических энцефалитах (ГЭ) у детей.Материалы и методы. Обследовано две группы детей, первая группа включала 25 детей в возрасте 6,0±4,8 года с лабораторно подтвержденным острым ГЭ, контрольная группа, сопоставимая по полу и возрасту,— 23 ребенка без признаков поражения центральной нервной системы. Оценка структурных изменений проводилась с помощью мультипараметрической МРТ головного мозга в режимах Т1-ВИ, Т2-ВИ, Flair, Т1-ВИ с контрастированием, а также с DWI, DTI и МРС.Результаты. В  40% случаев выявлен панэнцефалит, в  36% случаев  — лейкоэнцефалит, в  24%  — полиоэнцефалит. Наиболее часто в процесс были вовлечены большие полушария — 72% случаев, ствол головного мозга — 44%, таламус — 40% и базальные ядра — 36%. В 52% случаев были обнаружены изменения на DWI, в 20% случаев очаги накапливали контрастное вещество. Выявлено достоверное снижение фракционной анизотропии (FA) при DTI как в очаге, так и в интактной области у детей с ГЭ в сравнении с контрольной группой.Заключение. Применение мультипараметрической МРТ с использованием режимов DWI, DTI и МРС является важным диагностическим этапом для выявления и оценки очагового поражения головного мозга у детей с герпетическим энцефалитом.

EFFECT OF THE GAS MEDIA AND TEMPERATURE REGIMES OF ANNEALING ON THE PHASE COMPOSITION OF IRON BORATE FeBO3

Iron borate FeBO3 crystals are annealed in neutral, oxidizing, and reducing gas media on a specially designed setup. The effect of the chemical medium and annealing modes on the surface morphology and phase composition of the samples is established.Исследования выполнены при финансовой поддержке РФФИ, проект № 19-29-12016-мк, в части разработки экспериментальной установки и получения кристаллических образцов. Рентгеновские и электронно-микроскопические измерения проведены при под-держке Министерства науки и высшего образования РФ в рамках выполнения работ по Государственному заданию ФНИЦ «Кристаллография и фотоника» с использованием оборудования ЦКП (проект RFMEFI62119X0035)