Leitende Platte zwischen ausgeprägten Polen bei Wanderfelderregung

Übersicht Eine leitende Platte endlicher Permeabilität ist symmetrisch im Luftspalt zwischen zwei äquidistanten Folgen ausgeprägter Pole aus nichtleitendem, hochpermeablem Material angeordnet, deren Drehstromerregung ein magnetisches Wanderfeld hervorruft: Dieses wird zur analytischen Behandlung in zwei stationäre Wechselstromsysteme aufgespalten, für die getrennte Feldansätze formuliert werden. Durch Einführung der Matrizenschreibweise wird ein übersichtliches Verfahren zur Aufstellung der linearen Gleichungssysteme für die Feldkoeffizienten entwickelt, die numerisch ausgewertet werden. Durch Überlagerung beider Teilprobleme werden die resultierenden Feldgrößen und daraus Verluste und Anzugskräfte berechnet. Abschließend werden für den wichtigen Betriebsfall kleiner Frequenzen Näherungen angegeben, mit denen Verluste und Anzugskräfte ohne Inversion von Gleichungssystemen bestimmt werden können.

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Conducting plate between salient poles under travelling excitation

Contents A conducting permeable plate is symmetrically located with finite air-gap between two series of equidistantly placed honconducting, high-permeable salient poles, thea-c excitation of which causes a travelling magnetic field. The system is split into two stationary alternating current systems so as to investigate the given system analytically. This leads to two separate field postulates, the coefficients of which are numerically determined using a system of linear equations formulated in the matrix methods. The solutions of the splitsystems are then superimposed to give the resultant field values; using these, the losses and forces are calculated. Finally, approximations are given for the important case of small frequencies, applying which the losses and forces could be calculated without inverting the system of equations.

     

The effect of small additions of scandium on the properties of aluminium alloys

Additions of up to 1 wt% scandium have been made to Al, Al-Mg, Al-Mg-Ag and Al-Zn-Mg alloys and the effects on age-hardening and mechanical properties studied. Scandium levels up to 1% could be retained in solution at solidification rates of about 300 K s^–1. The precipitation of Al₃Sc at ageing temperatures in the range 563–593 K (290–320 °C) gave significant additional hardening. The low solubility of Sc in the solid state makes it difficult to obtain optimum hardening from Sc and other precipitating elements because of difficulties in solution treatment. The effect of deformation prior to ageing and the temperature-dependent mechanical properties are described.     

Using Knock-Out Mutants to Investigate the Adhesion of Staphylococcus aureus to Abiotic Surfaces

The adhesion of Staphylococcus aureus to abiotic surfaces is crucial for establishing device-related infections. With a high number of single-cell force spectroscopy measurements with genetically modified S. aureus cells, this study provides insights into the adhesion process of the pathogen to abiotic surfaces of different wettability. Our results show that S. aureus utilizes different cell wall molecules and interaction mechanisms when binding to hydrophobic and hydrophilic surfaces. We found that covalently bound cell wall proteins strongly interact with hydrophobic substrates, while their contribution to the overall adhesion force is smaller on hydrophilic substrates. Teichoic acids promote adhesion to hydrophobic surfaces as well as to hydrophilic surfaces. This, however, is to a lesser extent. An interplay of electrostatic effects of charges and protein composition on bacterial surfaces is predominant on hydrophilic surfaces, while it is overshadowed on hydrophobic surfaces by the influence of the high number of binding proteins. Our results can help to design new models of bacterial adhesion and may be used to interpret the adhesion of other microorganisms with similar surface properties.     

AZTEC, a Preprocessing Program for Real-Time ECG Rhythm Analysis

A preprocessing program developed for real-time monitoring of the electrocardiogram by digital computer has proved useful for rhythm analysis. The program suppresses low amplitude signals, reduces the data rate by a factor of about 10, and codes the result in a form convenient for analysis.     

Schlackenführung des SDS-Verfahrens im dolomitisch zugestellten LD-Konverter

Der Einfluß der Temperatur und der Systemkomponenten auf die Sättigungsphasen der Schlacke beim Einsatz von Dolomit wird aufgezeigt. Da eine Darstellung der SDS-Schlacke über die gesamte Blasezeit in einem System nicht möglich ist, werden die Anfangsschlacken mit Temperaturen unter 1600°C und die Endschlacken bei 1600°C getrennt beschrieben. Für beide Temperaturbereiche liegen die Schlacken in Sättigungsgebieten. Mit der Elektronenstrahlmikrosonde sind die Schlackenphasen während des Blasablaufes mineralogisch untersucht worden. Neben Merwinit und Monticellit-Kirschsteinit konnten Dicalciumferrit und Dicalciumsilikat in den Anfangs- und Magnesiowüstit, Dicalciumsilikat und Dicalciumferrit in den Endschlacken erkannt werden. Es wurde der Schlackenweg während des Blasens in den Dreistoffsystemen CaO′-SiO′₂-FeO′ und CaO′-SiO′₂-MgO′ entlang den Sättigungsflächen verschiedener Phasenräume bei der jeweiligen Temperatur dargestellt. Die Arbeitsweise mit verbleibender flüssiger Schlacke der Vorschmelze und einer veränderten Temperaturführung im ersten Drittel des Blasprozesses durch späteres Setzen von Kalk und Schrott ermöglicht die schnelle Auflösung des vor Blasbeginn zugegebenen Dolomits und damit den gleichzeitigen Bestand von MgO- und CaO-gesättigten Phasen während der ganzen Blasezeit. Der Wechsel des MgO zwischen den verschiedenen Phasen wird durch die Basizität, die Temperatur und den Eisengehalt der Schlacke bestimmt. Eine Behinderung der Kalk- und Dolomitauflösung durch Silikathüllen kann nicht beobachtet werden.     

Linkage coupler curve synthesis: A historical review — I. Developments up to 1875Synthese der Gelenk-Koppelkurve: ein historischer Überblick. Teil I—Entwicklungen bis 1975

This work has been presented in three parts. Commencing as a historical survey, the first part traces the early events relating to mechanical inventions and their applications that were instrumental in, but preceded, the eventual development of the science of linkage mechanism as originally expounded by Reuleaux. Analytical studies of the properties of coupler curves are reviewed in part two, commencing with the year 1875, when Samuel Roberts published the first account of the algebraic properties of the planar four-bar curve. This is followed, in part three, by a classification and critical examination of the techniques of coupler curve synthesis. However, techniques centered exclusively on graphical constructions have been placed outside the scope of this review, partly because of their limited usefulness in three-dimensional kinematics.     

Analyzing business process anomalies using autoencoders

Businesses are naturally interested in detecting anomalies in their internal processes, because these can be indicators for fraud and inefficiencies. Within the domain of business intelligence, classic anomaly detection is not very frequently researched. In this paper, we propose a method, using autoencoders, for detecting and analyzing anomalies occurring in the execution of a business process. Our method does not rely on any prior knowledge about the process and can be trained on a noisy dataset already containing the anomalies. We demonstrate its effectiveness by evaluating it on 700 different datasets and testing its performance against three state-of-the-art anomaly detection methods. This paper is an extension of our previous work from 2016 (Nolle et al. in Unsupervised anomaly detection in noisy business process event logs using denoising autoencoders. In: International conference on discovery science, Springer, pp 442–456, 2016). Compared to the original publication we have further refined the approach in terms of performance and conducted an elaborate evaluation on more sophisticated datasets including real-life event logs from the Business Process Intelligence Challenges of 2012 and 2017. In our experiments our approach reached an \(F_1\) score of 0.87, whereas the best unaltered state-of-the-art approach reached an \(F_1\) score of 0.72. Furthermore, our approach can be used to analyze the detected anomalies in terms of which event within one execution of the process causes the anomaly.     

Improved simulated annealing with step width adaptation for Langmuir probe tuning

In a previous investigation, a simulated annealing (SA) method was developed to optimize 14 Fourier terms in a radio-frequency waveform for active compensation of a Langmuir probe system. This approach was shown to find better solutions in less time than skilled human operators. However, variations in fitness indicated that the SA algorithm did not always find the precise global solution, although it came consistently close to it. This variability was caused by the limited number of fitness evaluations available due to time constraints. In this research, the chosen maximum step width has been shown to have a significant effect on the overall performance of the algorithm. A scaling function has been developed to adapt the maximum step width of the SA algorithm, on-line, as a function of the number of elapsed iterations. The modified algorithm has been shown to find fitter solutions with reduced variability in fitness.