Cosmic-ray driven dynamo in galaxies

We present recent developments of global galactic-scale numerical models of the Cosmic Ray (CR) driven dynamo, which was originally proposed by Parker (1992). We conduct a series of direct CR+MHD numerical simulations of the dynamics of the interstellar medium (ISM), composed of gas, magnetic fields and CR components. We take into account CRs accelerated in randomly distributed supernova (SN) remnants, and assume that SNe deposit small-scale, randomly oriented, dipolar magnetic fields into the ISM. The amplification timescale of the large-scale magnetic field resulting from the CR-driven dynamo is comparable to the galactic rotation period. The process efficiently converts small-scale magnetic fields of SN-remnants into galactic-scale magnetic fields. The resulting magnetic field structure resembles the X-shaped magnetic fields observed in edge-on galaxies.Comment: 6 pages, 4 figures, to appear in Proceedings of IAU Symp. 274, Advances in Plasma Astrophysics, ed. A. Bonanno, E. de Gouveia dal Pino and A. Kosoviche

Fluctuations in methane and carbon dioxide concentrations in the nearsurface zone and their genetic characterization in abandoned and active coal mines in the SW part of the Upper Silesian Coal Basin, Poland

The objective of this paper is to determine the origin and variability of methane and carbon dioxide concentrations in the near-surface zone and of coalbed methane in the SW part of the Chwałowice Trough and adjacent areas of the Main Syncline of the Upper Silesian Coal Basin (USCB). For this purpose soil-gas samples were taken at 202 measuring points, arranged along 5 profiles located in the mining area of the abandoned 1 Maja mine and directly adjacent areas as well as in the vicinity of four abandoned and remediated mining shafts. The maximum methane and carbon dioxide concentrations in the gas samples measured exceeds 22 and 9 vol%, respectively. The carbon isotope composition of methane and carbon dioxide was determined in samples in which elevated concentrations of these gases were found. Moreover, seven coalbed gas samples and bituminous coals were collected from coal seams exclusively from virgin parts of the Anna, Marcel, Jastrzębie, and Zofiówka mines. These data were supplemented with results of archival research for genetic interpretation of coalbed gases. Research reveals that typical humic low- and medium-volatile bituminous coals occur in Mississippian and Pennsylvanian coal-bearing strata in the study area. Fluctuations in methane and carbon dioxide concentration in the near-surface zone are related to the lithostratigraphy and tectonics of the area as well as to complicated methane depth distribution. Faults may play an important role in the microseepage of gases from deep to the near-surface zone. The connection of near-surface gases with subsurface gases was confirmed by similar stable carbon isotope composition in the methane recorded in the soil-gas samples and in the gas samples from the coal seams and sandstones of the Carboniferous formations. Distribution of anomalous methane concentrations recorded in soil-gas samples taken from profiles may indicate natural gas accumulations in the top zone of the Pennsylvanian coal-bearing formations. One example of this kind of accumulation is the Marklowice natural gas field, located within the mining area of the Marcel coal mine. Relatively high methane concentrations measured in soil gas in the vicinity of shafts I and III indicate that the degassing systems of closed and remediated mining shafts are not fully effective. Increases in carbon dioxide concentrations in the surface zone and frequent associated decreases in methane concentration were most often the result of microbial methane oxidation

The effect of Fe, Co, and Ni structural promotion of cryptomelane (KMn8O16)(KMn_8O_{16}) on the catalytic activity in oxygen evolution reaction

Transition metal (Fe, Co, Ni)-doped cryptomelane materials (K-OMS-2) were synthesized and characterized with the use of XRD, Raman spectroscopy, XPS, N2-BET, H2-TPR, and SEM. The electrocatalytic reactivity in oxygen evolution was evaluated with the use of the rotating disk electrode. It was found that the electrocatalytic activity is substantially enhanced for the cobaltdoped material, while iron and nickel doping have no, or even, negative effect on K-OMS-2. The structure of the material bulk is preserved in all cases, but the formation of additional birnessite phases can be evidenced for the iron and cobalt dopants. It is discussed that the reactivity enhancement of Co/K-OMS-2 can be related not only to the formation of cobalt-doped heterophases (cobaltane, birnessite) but also to the changes of the properties of pristine cryptomelane

Simulating magnetic fields in the Antennae galaxies

We present self-consistent high-resolution simulations of NGC4038/4039 (the "Antennae galaxies") including star formation, supernova feedback and magnetic fields performed with the N-body/SPH code Gadget, in which magnetohydrodynamics are followed with the SPH method. We vary the initial magnetic field in the progenitor disks from 1 nG to 100 muG. At the time of the best match with the central region of the Antennae system the magnetic field has been amplified by compression and shear flows to an equilibrium field of approximately 10 muG, independent of the initial seed field. These simulations are a proof of the principle that galaxy mergers are efficient drivers for the cosmic evolution of magnetic fields. We present a detailed analysis of the magnetic field structure in the central overlap region. Simulated radio and polarization maps are in good morphological and quantitative agreement with the observations. In particular, the two cores with the highest synchrotron intensity and ridges of regular magnetic fields between the cores and at the root of the southern tidal arm develop naturally in our simulations. This indicates that the simulations are capable of realistically following the evolution of the magnetic fields in a highly non-linear environment. We also discuss the relevance of the amplification effect for present day magnetic fields in the context of hierarchical structure formation.Comment: 18 pages, 14 figures, accepte

Magnetic field structure due to the global velocity field in spiral galaxies

We present a set of global, self-consistent N-body/SPH simulations of the dynamic evolution of galactic discs with gas and including magnetic fields. We have implemented a description to follow the evolution of magnetic fields with the ideal induction equation in the SPH part of the Vine code. Results from a direct implementation of the field equations are compared to a representation by Euler potentials, which pose a div(B)-free description, an constraint not fulfilled for the direct implementation. All simulations are compared to an implementation of magnetic fields in the Gadget code which includes also cleaning methods for div(B). Starting with a homogeneous seed field we find that by differential rotation and spiral structure formation of the disc the field is amplified by one order of magnitude within five rotation periods of the disc. The amplification is stronger for higher numerical resolution. Moreover, we find a tight connection of the magnetic field structure to the density pattern of the galaxy in our simulations, with the magnetic field lines being aligned with the developing spiral pattern of the gas. Our simulations clearly show the importance of non-axisymmetry for the evolution of the magnetic field.Comment: 17 pages, 18 figure

Knowing your place and commanding space:de/constructions of gendered embodiment in mixed-sex karate

Feminists have long acknowledged that gendered divisions in access to spaces of leisure, and how women and men physically take up that space, reproduces gender inequality. This article will explore how karate practitioners participate in the space of mixed-sex karate practice and how such uses of space de/construct gendered embodiments and a gender hierarchy. Data presented is drawn from nine months of ethnographic emersion within three karate clubs and fifteen photo-elicitation interviews with karate participants from the three clubs. The findings of this paper suggest that whilst women often occupied spaces of expertise within the karate hall, gendered distinctions in uses of space emerged in the more subtle ways in which women and men used their voice, responded to the tacit and smelt dilemmas of sweat, and moved their bodies across physical space. This research highlights both the potential of physical leisure practice to ‘undo’ conventional gendered embodiments that particularly restrict women’s intentionality in the world (Young, 1980), and the power of spatially-attuned research to illuminate the minute ways in which unequal gender relations are naturalised, legitimised and done

Electrical Quality Assurance of the Superconducting Circuits during LHC Machine Assembly

Based on the LHC powering reference database, all-together 1750 superconducting circuits were connected in the various cryogenic transfer lines of the LHC machine. Testing the continuity, magnet polarity, and the quality of the electrical insulation were the main tasks of the Electrical Quality Assurance (ELQA) activities during the LHC machine assembly. With the assembly of the LHC now complete, the paper reviews the work flow, resources, and the qualification results including the different types of electrical non-conformities

'Working out’ identity: distance runners and the management of disrupted identity

This article contributes fresh perspectives to the empirical literature on the sociology of the body, and of leisure and identity, by analysing the impact of long-term injury on the identities of two amateur but serious middle/long-distance runners. Employing a symbolic interactionist framework,and utilising data derived from a collaborative autoethnographic project, it explores the role of ‘identity work’ in providing continuity of identity during the liminality of long-term injury and rehabilitation, which poses a fundamental challenge to athletic identity. Specifically, the analysis applies Snow and Anderson’s (1995) and Perinbanayagam’s (2000) theoretical conceptualisations in order to examine the various forms of identity work undertaken by the injured participants, along the dimensions of materialistic, associative and vocabularic identifications. Such identity work was found to be crucial in sustaining a credible sporting identity in the face of disruption to the running self, and in generating momentum towards the goal of restitution to full running fitness and reengagement with a cherished form of leisure. KEYWORDS: identity work, symbolic interactionism, distance running, disrupted identit

Precision bond lengths for Rydberg Matter clusters KN (N = 19, 37, 61 and 91) in excitation levels n = 4 - 8 from rotational radio-frequency emission spectra

Clusters of the electronically excited condensed matter Rydberg Matter (RM) are planar and six-fold symmetric with magic numbers N = 7, 19, 37, 61 and 91. The bond distances in the clusters are known with a precision of +- 5% both from theory and Coulomb explosion experiments. Long series of up to 40 consecutive lines from rotational transitions in such clusters are now observed in emission in the radio-frequency range 7-90 MHz. The clusters are produced in five different vacuum chambers equipped with RM emitters. The most prominent series with B = 0.9292 +- 0.0001 MHz agrees accurately with expectation (within 2%) for the planar six-fold symmetric cluster K19 in excitation level n = 4. Other long series agree even better with K19 at n = 5 and 6. The ratio between the interatomic distance and the theoretical electron orbit radius (the dimensional ratio) for K19 in n = 4 is found to be 2.8470 +- 0.0003. For clusters K19 (n = 6) and K37 (n = 7 and 8) the dimensional ratio 2.90 is the highest value that is found, which happens to be exactly the theoretical value. Clusters K61 and K91 in n = 5 and 6 have slightly lower dimensional ratios. This is expected since the edge effects are smaller. Intensity alternations are observed of approximately 7:3. The nuclear spins interact strongly with the magnetic field from the orbiting electrons. Spin transitions are observed with energy differences corresponding accurately (within 0.6%) to transitions with apparent total (delta)F = -3 at excitation levels n = 5 and 6. The angular momentum coupling schemes in the clusters are complex but well understood.Comment: 37 pages, 14 figure