Structured outflow from a dynamo active accretion disc

We present an axisymmetric numerical model of a dynamo active accretion disc. If the dynamo-generated magnetic field in the disc is sufficiently strong (close to equipartition with thermal energy), a fast magneto-centrifugally driven outflow develops within a conical shell near the rotation axis, together with a slower pressure driven outflow from the outer parts of the disc as well as around the axis. Our results show that a dynamo active accretion disc can contribute to driving an outflow even without any external magnetic field. The fast outflow in the conical shell is confined by the azimuthal field which is produced by the dynamo in the disc and advected to the disc corona. This part of the outflow has high angular momentum and is cooler and less dense than its surroundings. The conical shell's half-opening angle is typically about 30 degrees near the disc and decreases slightly with height. The slow outflow is hotter and denser.Comment: 20 pages, 25 figures, accepted for publication in A&

Is nonhelical hydromagnetic turbulence peaked at small scales?

Nonhelical hydromagnetic turbulence without an imposed magnetic field is considered in the case where the magnetic Prandtl number is unity. The magnetic field is entirely due to dynamo action. The magnetic energy spectrum peaks at a wavenumber of about 5 times the minimum wavenumber in the domain, and not at the resistive scale, as has previously been argued. Throughout the inertial range the spectral magnetic energy exceeds the kinetic energy by a factor of about 2.5, and both spectra are approximately parallel. At first glance, the total energy spectrum seems to be close to k^{-3/2}, but there is a strong bottleneck effect and it is suggested that the asymptotic spectrum is k^{-5/3}. This is supported by the value of the second order structure function exponent that is found to be \zeta_2=0.70, suggesting a k^{-1.70} spectrum.Comment: 6 pages, 6 figure

Outflows from dynamo-active protostellar accretion discs

An axisymmetric model of a cool, dynamo-active accretion disc is applied to protostellar discs. Thermally and magnetically driven outflows develop that are not collimated within 0.1 AU. In the presence of a central magnetic field from the protostar, accretion onto the protostar is highly episodic, which is in agreement with earlier work.Comment: 8 pages, 9 figures, to be published in: Magnetic fields and star formation: theory versus observations, eds: A. I. Gomez de Castro et al., Kluwer Acad. Publ., Dordrec

Анализ неоднородности почвенного покрова санитарно-защитной зоны воздушной линии электропередачи сверхвысокого напряжения

Объектом исследования являются земли санитарно-защитной зоны «ЛЭП ВЛ-500 кВ ПС "Итатская"-ПС "Ново-Анжерская" № 524» (кадастровый номер 42.00.2.41). Цель работы: оценка неоднородности земель санитарно-защитной зоны воздушной линии электропередач сверхвысокого напряжения по степени нарушенности почвенного покрова южной тайги Западной Сибири. В работе использованы натурные полевые обследования почвенного покрова санитарно-защитной зоны воздушной линии электропередачи сверхвысокого напряжения. В результате работы составлена карта антропогенных механических нарушений почвенного покрова санитарно-защитной зоны воздушной линии электропередачи сверхвысокого напряжения. Проанализированы почвенные нарушения по характеру распространения, форме и степени нарушенности.The object of the study are soil sanitary protection zone «Power transmission lines of 500 kV Substation «Itatsky» -PC «New-Anzherka» № 524" (cadastral number42.00.2.41). Objective: To assess heterogeneity of land sanitary protection zone of overhead power lines EHV according to the degree of soil disturbance of the southern taiga of Western Siberia. In the work used field survey of the soil cover of the sanitary protection zone of overhead power lines EHV. As a result of work compiled a map anthropogenic mechanical soil disturbance sanitary protection zone of overhead power lines EHV. Analyzed soil disturbances on the character of propagation, form and extent of the breach

Magnetic field generation in fully convective rotating spheres

Magnetohydrodynamic simulations of fully convective, rotating spheres with volume heating near the center and cooling at the surface are presented. The dynamo-generated magnetic field saturates at equipartition field strength near the surface. In the interior, the field is dominated by small-scale structures, but outside the sphere by the global scale. Azimuthal averages of the field reveal a large-scale field of smaller amplitude also inside the star. The internal angular velocity shows some tendency to be constant along cylinders and is ``anti-solar'' (fastest at the poles and slowest at the equator).Comment: 12 pages, 11 figures, 2 tables, to appear in the 10 Feb issue of Ap

Digital media in intergenerational communication: Status quo and future scenarios for the grandparent-grandchild relationship

Communication technologies play an important role in maintaining the grandparent-grandchild (GP-GC) relationship. Based on Media Richness Theory, this study investigates the frequency of use (RQ1) and perceived quality (RQ2) of established media as well as the potential use of selected innovative media (RQ3) in GP-GC relationships with a particular focus on digital media. A cross-sectional online survey and vignette experiment were conducted in February 2021 among N = 286 university students in Germany (mean age 23 years, 57% female) who reported on the direct and mediated communication with their grandparents. In addition to face-to-face interactions, non-digital and digital established media (such as telephone, texting, video conferencing) and innovative digital media, namely augmented reality (AR)-based and social robot-based communication technologies, were covered. Face-to-face and phone communication occurred most frequently in GP-GC relationships: 85% of participants reported them taking place at least a few times per year (RQ1). Non-digital established media were associated with higher perceived communication quality than digital established media (RQ2). Innovative digital media received less favorable quality evaluations than established media. Participants expressed doubts regarding the technology competence of their grandparents, but still met innovative media with high expectations regarding improved communication quality (RQ3). Richer media, such as video conferencing or AR, do not automatically lead to better perceived communication quality, while leaner media, such as letters or text messages, can provide rich communication experiences. More research is needed to fully understand and systematically improve the utility, usability, and joy of use of different digital communication technologies employed in GP-GC relationships

Can communication technologies reduce loneliness and social isolation in older people?: a scoping review of reviews

Background: Loneliness and social isolation in older age are considered major public health concerns and research on technology-based solutions is growing rapidly. This scoping review of reviews aims to summarize the communication technologies (CTs) (review question RQ1), theoretical frameworks (RQ2), study designs (RQ3), and positive effects of technology use (RQ4) present in the research field. Methods: A comprehensive multi-disciplinary, multi-database literature search was conducted. Identified reviews were analyzed according to the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) framework. A total of N = 28 research reviews that cover 248 primary studies spanning 50 years were included. Results: The majority of the included reviews addressed general internet and computer use (82% each) (RQ1). Of the 28 reviews, only one (4%) worked with a theoretical framework (RQ2) and 26 (93%) covered primary studies with quantitative-experimental designs (RQ3). The positive effects of technology use were shown in 55% of the outcome measures for loneliness and 44% of the outcome measures for social isolation (RQ4). Conclusion: While research reviews show that CTs can reduce loneliness and social isolation in older people, causal evidence is limited and insights on innovative technologies such as augmented reality systems are scarce

Bottleneck effect in three-dimensional turbulence simulations

At numerical resolutions around $512^3$ and above, three-dimensional energy spectra from turbulence simulations begin to show noticeably shallower spectra than $k^{-5/3}$ near the dissipation wavenumber (`bottleneck effect'). This effect is shown to be significantly weaker in one-dimensional spectra such as those obtained in wind tunnel turbulence. The difference can be understood in terms of the transformation between one-dimensional and three-dimensional energy spectra under the assumption that the turbulent velocity field is isotropic. Transversal and longitudinal energy spectra are similar and can both accurately be computed from the full three-dimensional spectra. Second-order structure functions are less susceptible to the bottleneck effect and may be better suited for inferring the scaling exponent from numerical simulation data.Comment: 8 pages, 6 figure

Jahrbuch des Archivs der deutschen Jugendbewegung. Vierter Band 1972

Entwicklungen des Laienspiels; Die Farben des Wandervogel; Aspekte des Wandels der Sozialstrukutr bündischer Gruppen vor und nach dem 2. Weltkriege; Bündische Gruppen in Österreich; Bund der Köngener, Bund Deutscher Jugendvereine; Nachruf