Технология проведения капитального ремонта резервной нитки подводного перехода магистрального газопровода в условиях Западной Сибири

Объектом иccледования являетcя резервная нитка через р. Обь на учаcтке газопровода. Цель работы – изучить и провеcти анализ технологий капитального ремонта резервной нитки подводного перехода в уcловиях Западной Cибири, а также выбор наиболее актуального технологичеcкого решения в cлучаях возникновения аварийных cитуаций. В процеccе иccледования проводилиcь раcчеты по определению толщины cтенки трубопровода, баллаcтировке трубопровода, проверка прочноcти и уcтойчивоcти, проверка на недопуcтимые плаcтичеcкие деформации.The object of the study is the reserve thread across the p. Ob at the site of the gas pipeline. The purpose of the work is to study and analyze the technologies of overhaul of the reserve thread of the underwater passage in Western Siberia, as well as the selection of the most relevant technological solution in the event of emergency situations. In the course of the study, calculations were carried out to determine the thickness of the wall of the pipeline, to balance the pipeline, to check the strength and stability, and to check for unacceptable plastic deformations

Detection of magnetic fields in the circumgalactic medium of nearby galaxies using Faraday rotation

Context. The existence of magnetic fields in the circumgalactic medium (CGM) is largely unconstrained. Their detection is important as magnetic fields can have a significant impact on the evolution of the CGM and, in turn, the fields can serve as tracers for dynamical processes in the CGM. Aims. With Faraday rotation of polarised background sources, we aim to detect a possible excess of the rotation measure in the surrounding area of nearby galaxies. Methods. We use 2,461 residual rotation measures (RRMs) observed with the LOw Frequency ARray (LOFAR), where the foreground contribution from the Milky Way is subtracted. The RRMs are then studied around a subset of 183 nearby galaxies that was selected by apparent $B$-band magnitude. Results. We find that, in general, the RRMs show no significant excess for small impact parameters (i.e. the perpendicular distance to the line of sight). However, if we only consider galaxies at higher inclination angles and sight lines that pass close to the minor axis of the galaxies, we find significant excess at impact parameters of less than 100 kpc. The excess in |RRM| is 3.7 $\rm rad\,m^{-2}$ with an uncertainty between $\pm 0.9~\rm rad\,m^{-2}$ and $\pm 1.3~\rm rad\,m^{-2}$ depending on the statistical properties of the background (2.8$\sigma$-4.1$\sigma$). With electron densities of ~$10^{-4}~\rm cm^{-3}$ this suggests magnetic field strengths of a few tenths of a micro Gauss. Conclusions. Our results suggest a slow decrease of the magnetic field strength with distance from the galactic disc such as expected if the CGM is magnetised by galactic winds and outflows.Comment: 5 pages, 4 figures, accepted as Letter to Astronomy and Astrophysic

Synthetic observations of spiral arm tracers of a simulated Milky Way analog

Context. The Faraday rotation measure (RM) is often used to study the magnetic field strength and orientation within the ionized medium of the Milky Way. Recent observations indicate an RM magnitude in the spiral arms that exceeds the commonly assumed range. This raises the question of how and under what conditions spiral arms create such strong Faraday rotation. Aims. We investigate the effect of spiral arms on Galactic Faraday rotation through shock compression of the interstellar medium. It has recently been suggested that the Sagittarius spiral arm creates a strong peak in Faraday rotation where the line of sight is tangent to the arm, and that enhanced Faraday rotation follows along side lines which intersect the arm. Here our aim is to understand the physical conditions that may give rise to this effect and the role of viewing geometry. Methods. We apply a magnetohydrodynamic simulation of the multi-phase interstellar medium in a Milky Way-type spiral galaxy disk in combination with radiative transfer in order to evaluate different tracers of spiral arm structures. For observers embedded in the disk, dust intensity, synchrotron emission, and the kinematics of molecular gas observations are derived to identify which spiral arm tangents are observable. Faraday rotation measures are calculated through the disk and evaluated in the context of different observer positions. The observer’s perspectives are related to the parameters of the local bubbles surrounding the observer and their contribution to the total Faraday rotation measure along the line of sight. Results. We reproduce a scattering of tangent points for the different tracers of about 6◦ per spiral arm similar to the Milky Way. For the RM, the model shows that compression of the interstellar medium and associated amplification of the magnetic field in spiral arms enhances Faraday rotation by a few hundred rad m−2 in addition to the mean contribution of the disk. The arm–interarm contrast in Faraday rotation per unit distance along the line of sight is approximately ∼ 10 in the inner Galaxy, fading to ∼ 2 in the outer Galaxy in tandem with the waning contrast of other tracers of spiral arms. We identify a shark fin pattern in the RM Milky Way observations and in the synthetic data that is characteristic for a galaxy with spiral arms