Solution of an industrially relevant coupled magneto–mechanical problem set on an axisymmetric domain

Eddy currents are generated when low frequency magnetic fields interact with conducting components and this, in turn, generates Lorentz forces, which can cause these metallic components to deform and vibrate. An important application of this magneto–mechanical coupling is in coil design for magnetic resonance imaging scanners, where such vibrations can have unwanted effects such as ghosting of images, reduction of the life span of devices and discomfort for the patient. This work is aimed at developing an accurate computational tool for better understanding these deformations by considering a benchmark problem proposed by Siemens plc (Kruip, personal communication, 2013) on an idealised axisymmetric geometry. We present a new fixed point algorithm and develop new weak variational statements, which use a stress tensor approach for force calculation and permit discretisation using H1 conforming hp-version finite elements. Numerical results are included, which show the importance of high order finite elements for predicting the eddy currents and the associated coupling in the resonance region

Improved selective background Monte Carlo simulation at Belle II with graph attention networks and weighted events

When measuring rare processes at Belle II, a huge luminosity is required, which means a large number of simulations are necessary to determine signal efficiencies and background contributions. However, this process demands high computation costs while most of the simulated data, in particular in case of background, are discarded by the event selection. Thus, filters using graph neural networks are introduced at an early stage to save the resources for the detector simulation and reconstruction of events discarded at analysis level. In our work, we improved the performance of the filters using graph attention and investigated statistical methods including sampling and reweighting to deal with the biases introduced by the filtering.Comment: to be published in ACAT 2022 proceedings in the Journal Of Physics: Conference Serie

Cut-and-paste for impulsive gravitational waves with Λ\Lambda: the mathematical analysis

Impulsive gravitational waves are theoretical models of short but violent bursts of gravitational radiation. They are commonly described by two distinct spacetime metrics, one of local Lipschitz regularity and the other one even distributional. These two metrics are thought to be ‘physically equivalent’ since they can be formally related by a ‘discontinuous coordinate transformation’. In this paper we provide a mathematical analysis of this issue for the entire class of nonexpanding impulsive gravitational waves propagating in a background spacetime of constant curvature. We devise a natural geometric regularisation procedure to show that the notorious change of variables arises as the distributional limit of a family of smooth coordinate transformations. In other words, we establish that both spacetimes arise as distributional limits of a smooth sandwich wave taken in different coordinate systems which are diffeomorphically related

Product Market Competition and Firms’ Disclosure of Cross-Segment Differences in Performance

This study examines how product market competition affects firms’ disclosures of their individual segment's performance. We explicitly account for different types of product market competition by distinguishing between competitors who are already active in a particular market and potential competitors who are considering entering the market. Arguably, firms that are subject to intensive existing competition have lower incentives to conceal information because they are less likely to exhibit abnormal profitability. By contrast, a high level of potential competition constitutes a threat to profitability and hence provides incentives to conceal segment performance. In line with these proprietary cost arguments, we find that potential competition is negatively associated with the disclosure of cross-segment differences in performance, whereas existing competition is positively associated with the disclosure of cross-segment differences in performance. Our results remain robust to a number of sensitivity tests

bacterial infection disrupts the circadian fluctuation of immune cells in wrinkle-lipped bats (Chaerephon plicatus)

Background Leukocyte concentrations follow a circadian pattern in mammals, with elevated values at times of potential contact with pathogens and parasites. We hypothesized that this pattern is disturbed after an immune challenge. Methods In Thailand, we captured wrinkle-lipped bats (Chaerephon plicatus), when they returned to their colony at dawn. We challenged half of the animals (experimental group) with bacterial lipopolysaccharides and treated the others only with the carrier liquid (control group). We then compared body mass changes and differences in circulating immune cell counts at 8 h post-treatment. Results In experimental animals, we observed an increase in total leukocyte and neutrophil numbers of 17% and 95%, respectively. In control animals, concentrations of leukocytes decreased by 44% and those of neutrophils remained constant. Experimental treatment had no effect on lymphocytes, yet changes in eosinophil numbers were explained by sex. Eosinophils decreased by 66% in females and by 62% in males. Basophils and monocytes were rarest among all observed cell types and analysis was either impossible because of low numbers or yielded no significant effects, respectively. Discussion Our findings show that a simulated bacterial infection triggered a neutrophil-associated immune response in wrinkle-lipped bats, indicating a disruption of the diurnal fluctuation of immune cells. Our study suggests that bats exhibit circadian rhythms in immune cell counts. The magnitude of these fluctuations may vary across species according to specific- specific infection risks associated with colony sizes or specific roosting habits

Novel Analytical Calculation Method for the Non-Linear Ψ -i- Characteristic of Switched-Reluctance-Machines in Arbitrary Rotor Positions

Abstract The non-linear Ψ -i-characteristic is crucial for the design of switched reluctance machines. Known analytical calculations are based on complex models of the magnetic circuit or on functions needing a fitting procedure (using measured or FEM-calculated data). In this paper, a method is presented that requires only very few input data, which can be deduced easily from the geometry of the machine. Comparisons with measured data show an acceptable correlation for arbitrary rotor positions, qualifying this method to be used in the design stage of new drives

Inside the group:Investigating social structures in player groups and their influence on activity

Social features, matchmaking, and grouping functions are key elements of online multiplayer experiences. Understanding how social connections form in and around games and their relationship to in-game activity offers insights for building and maintaining player bases and for improving engagement and retention. This paper presents an analysis of the groups formed by users of the the100.io-a social matchmaking website for different commercial titles, including Destiny on which we focus in this paper. Groups formed on the100.io can be described across a range of social network related metrics. Also, the social network formed within a group is evaluated in combination with user-provided demographic and preference data. Archetypal analysis is used to classify groups into archetypes and a correlation analysis is presented covering the effect of group characteristics on in-game activity. Finally, weekly activity profiles are described. Our results indicate that group size as well as the number of moderators within a group and their connectedness to other team members influences a group's activity. We also identified four prototypical types of groups with different characteristics concerning composition, social cohesion, and activity.</p

Der Virtuelle Campus der FH JOANNEUM und die berufsbegleitende Lehre

Der Beitrag beschreibt die Entwicklung, Umsetzung und Evaluierung von eLearning an den Studiengängen der FH JOANNEUM im Rahmen des Projekts Virtueller Campus. Auf die Beschreibung der FH JOANNEUM und seiner (berufsbegleitenden) Studiengänge folgt die Darstellung des eLearning Kompetenzzentrums „ZML - Innovative Lernszenarien“ und der Entwicklung des Virtuellen Campus. Ausgehend von den Bedürfnissen der Lehrenden und Studierenden an berufsbegleitenden Studiengängen werden die Maßnahmen und Erfahrungen aus der Einführung und Unterstützung von eLearning an zwei berufsbegleitenden Studiengängen vorgestellt. Abschließend wird ein Ausblick in die Zukunft des Virtuellen Campus versucht.  06.01.2010 | Irmgard Schinnerl-Beikircher, Maria Jandl & Jutta Pauschenwein (Graz