Influence of the interfaces on the anisotropic magnetoresistance of Ni/Co multilayers

3 pages, 5 figures.-- PACS: 75.70.Cn; 73.61.At; 73.50.JtAnisotropic magnetoresistance in Ni is found to increase abruptly when Co impurity layers are inserted. Some experiments carried out in different Ni/Co multilayers indicate that interfaces are responsible for the magnetoresistance enhancement.Peer reviewe

Measurement of the cosmic ray spectrum above 4×10184{\times}10^{18} eV using inclined events detected with the Pierre Auger Observatory

A measurement of the cosmic-ray spectrum for energies exceeding $4{\times}10^{18}$ eV is presented, which is based on the analysis of showers with zenith angles greater than $60^{\circ}$ detected with the Pierre Auger Observatory between 1 January 2004 and 31 December 2013. The measured spectrum confirms a flux suppression at the highest energies. Above $5.3{\times}10^{18}$ eV, the "ankle", the flux can be described by a power law $E^{-\gamma}$ with index $\gamma=2.70 \pm 0.02 \,\text{(stat)} \pm 0.1\,\text{(sys)}$ followed by a smooth suppression region. For the energy ($E_\text{s}$) at which the spectral flux has fallen to one-half of its extrapolated value in the absence of suppression, we find $E_\text{s}=(5.12\pm0.25\,\text{(stat)}^{+1.0}_{-1.2}\,\text{(sys)}){\times}10^{19}$ eV.Comment: Replaced with published version. Added journal reference and DO

Energy Estimation of Cosmic Rays with the Engineering Radio Array of the Pierre Auger Observatory

The Auger Engineering Radio Array (AERA) is part of the Pierre Auger Observatory and is used to detect the radio emission of cosmic-ray air showers. These observations are compared to the data of the surface detector stations of the Observatory, which provide well-calibrated information on the cosmic-ray energies and arrival directions. The response of the radio stations in the 30 to 80 MHz regime has been thoroughly calibrated to enable the reconstruction of the incoming electric field. For the latter, the energy deposit per area is determined from the radio pulses at each observer position and is interpolated using a two-dimensional function that takes into account signal asymmetries due to interference between the geomagnetic and charge-excess emission components. The spatial integral over the signal distribution gives a direct measurement of the energy transferred from the primary cosmic ray into radio emission in the AERA frequency range. We measure 15.8 MeV of radiation energy for a 1 EeV air shower arriving perpendicularly to the geomagnetic field. This radiation energy -- corrected for geometrical effects -- is used as a cosmic-ray energy estimator. Performing an absolute energy calibration against the surface-detector information, we observe that this radio-energy estimator scales quadratically with the cosmic-ray energy as expected for coherent emission. We find an energy resolution of the radio reconstruction of 22% for the data set and 17% for a high-quality subset containing only events with at least five radio stations with signal.Comment: Replaced with published version. Added journal reference and DO

Measurement of the Radiation Energy in the Radio Signal of Extensive Air Showers as a Universal Estimator of Cosmic-Ray Energy

We measure the energy emitted by extensive air showers in the form of radio emission in the frequency range from 30 to 80 MHz. Exploiting the accurate energy scale of the Pierre Auger Observatory, we obtain a radiation energy of 15.8 \pm 0.7 (stat) \pm 6.7 (sys) MeV for cosmic rays with an energy of 1 EeV arriving perpendicularly to a geomagnetic field of 0.24 G, scaling quadratically with the cosmic-ray energy. A comparison with predictions from state-of-the-art first-principle calculations shows agreement with our measurement. The radiation energy provides direct access to the calorimetric energy in the electromagnetic cascade of extensive air showers. Comparison with our result thus allows the direct calibration of any cosmic-ray radio detector against the well-established energy scale of the Pierre Auger Observatory.Comment: Replaced with published version. Added journal reference and DOI. Supplemental material in the ancillary file

The silicon photomultiplier telescope FAMOUS for the detection of fluorescence light

The faint fluorescence light of extensive air showers produced by cosmic rays is traditionally detected by means of optical telescopes equipped with photomultiplier tubes. Since these devices are fragile, the prototype telescope FAMOUS has been built to investigate the versatility of silicon photomultipliers whose photon detection efficiency surpasses the quantum efficiency of photomultiplier tubes. In this thesis, the 61 pixel telescope FAMOUS has been successfully commissioned and quantitative measurements of star trails have been performed. Furthermore, detailed simulations, especially for the silicon photomultipliers, have been developed and validated against measurements conducted in the laboratory

A Probabilistic MajorClust Variant for the Clustering of Near-Homogeneous Graphs

Clustering remains a major topic in machine learning; it is used e.g. for document categorization, for data mining, and for image analysis. In all these application areas, clustering algorithms try to identify groups of related data in large data sets. In this paper, the established clustering algorithm MajorClust ([12]) is improved; making it applicable to data sets with few structure on the local scale—so called near-homogeneous graphs. This new algorithm MCProb is verified empirically using the problem of image clustering. Furthermore, MCProb is analyzed theoretically. For the applications examined so-far, MCProb outperforms other established clustering techniques

Auswirkungen von Assistenzsystemen auf die Arbeit in der manuellen Montage

Sich verkürzende Innovations- und Produktlebenszyklen sowie eine zunehmende Variantenvielfalt verbunden mit kleineren Losgrößen bis hin zur kundenindividuellen Produktkonfiguration führen zu veränderten Anforderungen an die Gestaltung von Montagesystemen. Gleichzeitig bieten technologische Entwicklungen auf dem Gebiet der Assistenzsysteme neue Gestaltungsmöglichkeiten, Beschäftigte bei der Ausführung ihrer Arbeitsprozesse zu unterstützten. Der vorliegende Beitrag zeigt anhand eines Fallbeispiels, eines Montagearbeitsplatzes aus der SmartFactoryOWL in Lemgo, wie ein Montagearbeitsplatz über Assistenzfunktionen weiter entwickelt wurde und welche Auswirkungen diese Entwicklungen auf die Arbeit haben. Der Arbeitsplatz wurde im Rahmen eines Kooperationsprojektes des Labors für Industrial Engineering der Hochschule Ostwestfalen-Lippe und der Unternehmen Turck und Brandt Kantentechnik in der SmartFactory-OWL realisiert. Er verfügt über ein Assistenzsystem, welches dem Monteur auftrags- und arbeitsschrittbezogene Informationen bereitstellt. Das System besteht maßgeblich aus einem Pick-to-light System verbunden mit einem Touchscreen zur Visualisierung der Informationen. Der Montageauftrag wird über eine RFID-Applikation angemeldet. Damit lassen sich neue Produktvarianten flexibel hinzufügen und bestehende ändern. Zudem können die über Sensoren erfassten Daten zu Kennzahlen aggregiert und entsprechend der Anforderungen der Nutzer visualisiert werden. Im Rahmen des Beitrages werden die Auswirkungen dieser technologischen Weiterentwicklungen auf die Arbeit erörtert